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  Subjects -> CHEMISTRY (Total: 858 journals)
    - ANALYTICAL CHEMISTRY (53 journals)
    - CHEMISTRY (601 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (25 journals)
    - INORGANIC CHEMISTRY (42 journals)
    - ORGANIC CHEMISTRY (48 journals)
    - PHYSICAL CHEMISTRY (68 journals)

CHEMISTRY (601 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 11)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 39)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 19)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 24)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 40)
ACS Nano     Full-text available via subscription   (Followers: 258)
ACS Photonics     Full-text available via subscription   (Followers: 12)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 24)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chimica Slovenica     Open Access  
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 8)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 51)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 58)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 15)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 23)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 23)
Advances in Nanoparticles     Open Access   (Followers: 14)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 15)
American Journal of Chemistry     Open Access   (Followers: 28)
American Journal of Plant Physiology     Open Access   (Followers: 14)
American Mineralogist     Hybrid Journal   (Followers: 15)
Analyst     Full-text available via subscription   (Followers: 39)
Angewandte Chemie     Hybrid Journal   (Followers: 168)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 237)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 16)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 22)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 338)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 121)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 85)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 68)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 8)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 16)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 71)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 25)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 22)
Chemical Reviews     Full-text available via subscription   (Followers: 186)
Chemical Science     Open Access   (Followers: 23)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 31)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 149)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 20)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 42)
Chemistry of Materials     Full-text available via subscription   (Followers: 243)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 4)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 11)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography     Open Access   (Followers: 2)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 3)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal  
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 18)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 64)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 3)
Ecotoxicology and Environmental Contamination     Open Access  

        1 2 3 4 | Last

Journal Cover Chemistry - An Asian Journal
  [SJR: 1.833]   [H-I: 75]   [16 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1861-4728 - ISSN (Online) 1861-471X
   Published by John Wiley and Sons Homepage  [1592 journals]
  • Synthesis, Self-Assembly and Photoresponsive Liquid Crystals Based on
           Azobenzene Derivatives
    • Authors: Hongyan Wang; Yi Han, Wei Yuan, Mengjiao Wu, Yulan Chen
      Abstract: A new class of rod-coil-rod molecules with an azobenzene core were synthesized. They were found to form robust organogels in several kinds of organic solvents. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), FT-IR spectroscopy, UV-vis absorption spectroscopy, 1H NMR, and X-ray diffraction (XRD) revealed that in these organogels, the molecules self-assembled into nanofiber network with an H-type aggregation mode under the joint effect of Pi-Pi stacking, intermolecular hydrogen bonding, and van der Waals forces. Interestingly, the incorporation of the azobenzene mesogene into the rigid core led to photo-isomerizable liquid crystal materials, which exhibited fast responsiveness to light and temperature, along with the trans-cis transition stimulated by UV light and heating.
      PubDate: 2018-02-17T08:40:24.391498-05:
      DOI: 10.1002/asia.201800019
       
  • Transition-Metal-Catalyzed Cyanation by Using an Electrophilic Cyanating
           Agent, N-Cyano-N-phenyl-p-toluenesulfonamide (NCTS)
    • Authors: Jie Cui; Jian Song, Qing Liu, Hui Liu, Yunhui Dong
      Abstract: The ability to introduce a nitrile group into a biologically active compound is very useful in organic synthesis, owing to the importance of nitrile groups in transformations and tuning molecular properties. To date, nucleophilic cyanation has been the most used strategy for this purpose, whilst electrophilic cyanation reactions are less developed. Recently, the electrophilic cyanation reagent N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) has received increasing attention, owing to its superior properties in terms of safety and practicality. This Focus Review summarizes recent progress in transition-metal-catalyzed cyanation reactions that use NCTS.I believe I C≡N fly: The electrophilic cyanation reagent N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) has received increasing attention in cyanation reactions because of its superior properties in terms of safety and practicality. This Focus Review summarizes recent progress in transition-metal-catalyzed cyanation reactions with NCTS.
      PubDate: 2018-02-15T05:41:40.465204-05:
      DOI: 10.1002/asia.201701611
       
  • QM/MM Studies on the Photoisomerization Dynamics of Azobenzene Chromophore
           Tethered to a DNA Duplex: Local Unpaired Nucleobase Plays a Crucial Role
    • Authors: Dan Wu; Ya-Ting Wang, Wei-Hai Fang, Ganglong Cui, Walter Thiel
      Abstract: The photoresponsive azobenzene-tethered DNAs have received growing experimental attention because of their potential applications in biotechnology and nanotechnology; however, little is known about the initial photoisomerization of azobenzene in these systems. Herein we have employed quantum mechanics/molecular mechanics (QM/MM) methods to explore the photoisomerization dynamics of an azobenzene-tethered DNA duplex. We find that in the S₁ state the trans-cis photoisomerization path is much steeper in DNA than in vacuo, which makes the photoisomerization much faster in the DNA environment. This acceleration is primarily caused by complex steric interactions between azobenzene and the nearby unpaired thymine nucleobase, which also change the photoisomerization mechanism of azobenzene in the DNA duplex.
      PubDate: 2018-02-15T01:05:29.246618-05:
      DOI: 10.1002/asia.201800006
       
  • Isomeric N-annulated Perylene Diimide Dimers for Organic Solar Cells
    • Authors: Zetong Ma; Huiting Fu, Dong Meng, Wei Jiang, Yanming Sun, Zhaohui Wang
      Abstract: Two isomeric N-annulated perylene diimide dimers, namely p-BDNP and m-BDNP were designed and synthesized via geometric tuning. Distinct molecular geometry and packing arrangements of isomers with almost identical optical and electrochemical properities rendered us an in-depth understanding of molecular structure-aggregation state-photovoltaic performance. Blended with commercially available donor PCE-10, p-BDNP and m-BDNP showed distinct differences in photovoltaic performance with power conversion efficiencies (PCEs) of 5.01% and 4.15%, respectively.
      PubDate: 2018-02-14T11:05:44.907814-05:
      DOI: 10.1002/asia.201800058
       
  • Probing the Most Aromatic and Antiaromatic Pyrrolium Rings by Maximizing
           Hyperconjugation and Push-Pull Effect
    • Authors: Tingting Sun; Qiong Xie, Liang Zhao, Jun Zhu
      Abstract: Hyperconjugation, a weak interaction in organic chemistry, can have a strong effect on aromaticity, leading to the concept of hyperconjugative aromaticity, which was first proposed by Mulliken in 1939. However, most studies are limited to the main group chemistry. Here we report the most aromatic and antiaromatic pyrrolium ring by maximizing the hyperconjugation caused by transition metal fragments and push-pull effect. Our calculations reveal that the origin of the outperformance of transition metal substituents over main group ones on hyperconjugative aromaticity could be attributed to their higher highest occupied molecular orbitals (HOMOs). Among group 11 transition metals, silver substituent has the best performance. All these findings highlight the magic of the transition metal (silver) and could be particularly helpful for the design of other aromatic and antiaromatic counterparts based on a nonaromatic parent species.
      PubDate: 2018-02-14T04:35:24.514159-05:
      DOI: 10.1002/asia.201800179
       
  • New strategies in the design of nanomedicine to oppose uptake by the
           mononuclear phagocyte system for enhancing cancer therapeutic efficacy
    • Authors: Yiming Zhou; Zhifei Dai
      Abstract: The application of nanotechnology in tumor treatment has boomed the vigorous development in cancer nanomedicine. In spite of the great success has been achieved in this field, the nanomedicine has not realized its full potential owing to a delivery barrier, the mononuclear phagocytic system (MPS), which cuts off more than 95 % of the administrated nanoparticles. This results in an extremely low drug delivery efficacy to the tumor, leading to poor therapeutic outcomes. Moreover, the excessive injection of nanoparticles also raises toxicity concern caused by the accumulation of nanomaterials in the organs like liver and spleen. Therefore, reducing the nanomedicine uptake by the MPS is vital to enhance the cancer therapeutic efficacy and decrease the side effects. In this review, we will focus on the new strategies about how to reduce the nanoparticle uptake by the macrophages based on the current knowledge about the bio-nano interaction. Further directions will also be highlighted for the development of cancer nanomedicine with lower 'off target' rate and better therapeutic outcomes.
      PubDate: 2018-02-13T23:35:22.314326-05:
      DOI: 10.1002/asia.201800149
       
  • Drug Self-delivery Systems based on Hyperbranched Polyprodrugs towards
           Tumor Therapy
    • Authors: Jie Kong; Xiao Duan, Jianxin Chen, Yanlan Wu, Si Wu, Yan Shao
      Abstract: In this contribution, we developed amphiphilic hyperbranched polyprodrugs (DOX-S-S-PEG) with drug repeat units in hydrophobic core linked by disulfide bonds as drug self-delivery systems for cancer therapy. The amphiphilic micelles from DOX-S-S-PEG can be disrupted under glutathione (1mg mL−1) circumstance. Cell viability of A549 cells and 293T cells was evaluated by CCK-8 and Muse Annexin V & Dead Cell Kit. The disrupted polyprodrugs maintained drug activity for killing tumor cells. Meanwhile, the un-disrupted polyprodrugs possessed low cytotoxicity to normal cells. The cell uptake experiments showed that the micelles of DOX-S-S-PEG were taken up by A549 cells and distributed to cell nuclei. Thus, the drug self-delivery systems with drug repeat units in hydrophobic cores linked by disulfide bonds show significant special advantages, which make them as perfect drug self-delivery systems for potential high efficient cancer therapy.
      PubDate: 2018-02-13T13:05:29.548674-05:
      DOI: 10.1002/asia.201701697
       
  • Ion-Pair SN2 Reaction of OH− and CH3Cl: Activation Strain analyses of
           Counterion and Solvent Effects
    • Authors: Jalal Z. A. Laloo; Lydia Rhyman, Olatz Larrañaga, Ponnadurai Ramasami, Matthias Bickelhaupt, Abel de Cozar Ruano
      Abstract: We have theoretically studied the non-identity SN2 reactions of MnOH(n-1) + CH3Cl (M+ = Li+, Na+, K+, and MgCl+; n = 0, 1) in the gas phase and in THF solution at OLYP/6-31++G(d,p) using PCM implicit solvation. We want to explore and understand the effect of the metal counterion M+ and solvation on the reaction profile and the stereoselectivity of these processes. To this end we have explored the potential energy surfaces of the backside (SN2-b) and frontside (SN2-f) pathways. To explain the computed trends, we have carried out analyses with an extended activation strain model (ASM) of chemical reactivity that includes the treatment of solvation effects.
      PubDate: 2018-02-13T11:05:46.342563-05:
      DOI: 10.1002/asia.201800082
       
  • Copper-Catalyzed Asymmetric Synthesis of Borylated cis-Disubstituted
           Indolines
    • Authors: Jaesook Yun; DingXi Li, Jiwon Kim, Jung Woon Yang
      Abstract: A copper-catalyzed, intramolecular borylative cyclization of vinyl arenes with imines is reported, which affords enantio-enriched indolines as a single diastereomer under mild conditions. A benzylcopper species is generated by Cu−Bpin addition to the alkene, which then acts as a nucleophile for intramolecular imine addition. The reaction is applicable to various vinyl arenes with an imine moiety at the ortho-position, including heterocycles, for formation of borylated indolines in good yields and ee up to 90%.
      PubDate: 2018-02-12T23:30:30.415462-05:
      DOI: 10.1002/asia.201800121
       
  • Recent Progress in Chemistry of Multiple Helicenes
    • Authors: Changqing Li; Yong Yang, Qian Miao
      Abstract: The recent decade has witnessed multiple helicenes arsing as an interesting class of nonplanar polycyclic aromatics of inherent multihelicity. These molecules present esthetic structures and interesting properties that are not available to helicenes of single helicity. This Focus Review aims to provide an overview of multiple helicenes in respect of structures, stereochemical dynamics, synthesis and applications. Herein we first survey recently reported multiple helicenes with emphasis on molecular structures and stereochemistry of multiple carbohelicenes. After this survey, we discuss synthesis of multiple helicenes using the Scholl reaction and summarize recent applications of multiple helicenes in organic electronics. On the basis of these discussions, we finally reach conclusions on the current status of multiple helicenes and provide an outlook for this field.
      PubDate: 2018-02-12T13:00:25.768325-05:
      DOI: 10.1002/asia.201800073
       
  • Stereodivergent Hydroboration of Allenes
    • Authors: Yoshiyuki Nagashima; Keiji Sasaki, Takahiro Suto, Takaaki Sato, Noritaka Chida
      Abstract: Full details of the stereodivergent hydroboration of allenes are reported. While hydroboration of an allene with 9-BBN provided a thermodynamically stable (E)-allylic alcohol after oxidative work-up, the reaction of an identical allene with HB(Sia)2 formed a (Z)-allylic alcohol as the kinetic product. The developed conditions allowed for the synthesis of trisubstituted olefins in a highly stereoselective fashion, which is known to be challenging. The method was also applied to the stereodivergent synthesis of structural motifs such as skipped dienes and allylbenzenes, which are often embedded in biologically active natural products.
      PubDate: 2018-02-12T09:00:34.608935-05:
      DOI: 10.1002/asia.201800134
       
  • Coupling of Bifunctional CoMn-Layered Double Hydroxide@Graphitic-C3N4
           Nanohybrids towards Efficient Photoelectrochemical Overall Water splitting
           
    • Authors: Dongpeng Yan; Muhammad Arif, Ghulam Yasin, Muhammad Shakeel, Xiaoyu Fang, Rui Gao, Shengfu Ji
      Abstract: The development of durable, low cost and efficient photo/electrolysis for oxygen/hydrogen evolution reactions (OER and HER) is important to fulfill the increasing energy requirement. In this work, high-efficiency and active photo/electrochemical catalysts, CoMn-LDH@g-C3N4 hybrids, have been synthesized successfully through a facile in situ co-precipitation method at room temperature. The CoMn-LDH@g-C3N4 composite exhibits an obvious OER electrocatalytic performance with current density of 40 mA·cm-2 at overpotential of 350 mV for water oxidation, which is 2.5 times higher than pure CoMn-LDH nanosheets. For HER, to reach a current density of 50 mA·cm2, CoMn-LDH@g-C3N4 (η50 = −448 mV) requires close potential to Pt/C (η50 = −416 mV). Furthermore, under visible light irradiation, the photocurrent density of CoMn-LDH@g-C3N4 composite is 0.227 mA·cm-2, which is 2.1 and 3.8 time higher than the pristine CoMn-LDH (0.108 mA·cm-2) and g-C3N4 (0.061 mA·cm-2), respectively. CoMn-LDH@g-C3N4 composite delivers a current density of 10 mA·cm-2 at 1.56 V and 100 mA·cm-2 at 1.82 V for overall water splitting. Therefore, this work establishes the first example of pure CoMn-LDH and CoMn-LDH@g-C3N4 hybrids as electrochemical and photoelectrochemical water splitting applications for both OER and HER, which may open a pathway to develop and explore other LDH and g-C3N4 nanosheets as efficient catalysts for renewable energy application.
      PubDate: 2018-02-12T07:00:25.279878-05:
      DOI: 10.1002/asia.201800016
       
  • Carbon and Carbon Hybrid Materials as Anodes for Sodium Ion Batteries
    • Authors: Yan Yu; Xiongwu Zhong, Ying Wu, Sifan Zen
      Abstract: Sodium ion batteries (SIBs) have attracted much attention for application in large-scale grid energy storage due to the abundance and low-cost sodium sources. However, the low energy density and poor cycling life hinder the practice application of SIBs. Recently, substantial efforts have been made to develop electrode materials to push forward large-scale practical application. Carbon materials can be directly used as anode materials, showing excellent sodium storage performance. Additionally, designing and constructing carbon hybrid materials is an effective strategy to obtain high-performance anodes for SIBs. In this review, we summarize recent research progress of carbon and carbon hybrid materials as anodes for SIBs. Nanostructural design to enhance the sodium storage performance of anode materials is discussed, and we offer some insight on the potential directions and future high-performance anode materials of SIBs.
      PubDate: 2018-02-12T03:30:22.442816-05:
      DOI: 10.1002/asia.201800132
       
  • Ferroelectric Liquid Crystals: Synthesis and Thermal Behavior of Optically
           Active, Three-Ring Schiff bases and Salicylaldimines
    • Authors: Channabasaveshwar Veerappa Yelamaggad; Bhyranalyar N Veerabhadraswamy, Doddamane S Shankar Rao
      Abstract: Herein we report the design, synthesis and thermal behavior of twenty new optically active, three-ring calamitic LCs belonging to four series. The first two series comprise five pairs of enantiomeric Schiff bases while the other two series are composed of five pairs of enantiomeric salicylaldimines. In each pair of optical isomers the configuration of a chiral centre in one stereoisomer is opposite to that of the analogous centre in the other isomer as they are derived from (3S)-3,7-dimethyloctyloxy and (3R)-3,7-dimethyloctyloxy tails. The thermal behavior of the compounds was established using a combination of optical polarizing microscopy, differential scanning calorimetry and powder X-ray diffraction. These complementary techniques evidence the existence of the expected, thermodynamically stable, chiral smectic C (SmC*) LC phases besides blue phase-I/II (BPI or BPII) and chiral nematic (N*) phases. The vast majority of the Schiff bases show an additional metastable, unfamiliar smectic (SmX) phase just below the SmC* phase. Notably, the SmC* phase persists over the temperature span of ~ 80-115 ºC. Two mesogens chosen each from Schiff bases and salicylaldimines were investigated for their electrical switching behavior. The study reveals the ferroelectric switching characteristics of the SmC* phase featuring the spontaneous polarization (PS) in the range of 69 to 96 nC/cm2. The helical twist sense of the SmC* phases as well as the N* phase formed by a pair of enantiomeric Schiff base as well as salicylaldimines has been established with the help of circular dichroism (CD) spectroscopic technique. The reversal of helical handedness from left to right and vice-versa has been evidenced during the N* to SmC* phase transition implying that the screw sense of the helical array of the N* phase and the SmC* phase of an enantiomer is opposite.
      PubDate: 2018-02-10T07:25:31.553697-05:
      DOI: 10.1002/asia.201800119
       
  • Programmable self-assembly of heterometallic palladium(II)-copper(II) 1-D
           grid-chain using dinuclear palladium(II) corners with pyrazole-carboxylic
           acid ligands
    • Authors: Wen-Qing Sun; Jin Tong, Hong-Lin Lu, Ting-Ting Ma, Shu-Yan Yu, Hong-Wei Ma
      Abstract: A novel heterometallic diPd(II)-diCu(II) grid-chain, {[(bpy)4Pd4Cu2L4](NO3)4}n (2) was synthesized through a programmable self-assembly approach from the molecular corners [(bpy)2Pd2(HL)(L)](NO3) (1) as linkers with Cu(II) nitrate, using the bifunctional ligand H2L featuring the primary (pyrazole) and secondary (benzoic acid) groups. Structural analysis revealed that the 1-D structure 2 consists of one [Cu2(O2CPh)4]n unit as bridges and two [(bpy)2Pd2L2]n corners. Additionally, the heterometallic synergy on catalytic effect in Suzuki coupling reaction using 2 was further discussed.
      PubDate: 2018-02-09T10:55:21.377333-05:
      DOI: 10.1002/asia.201701766
       
  • Efficient Aliphatic C-H Bonds Oxidation Catalyzed by Manganese Complex
           with Hydrogen Peroxide
    • Authors: Wei Sun; Wenfang Wang, Daqian Xu, Qiangsheng Sun
      Abstract: A tetradentate nitrogen ligand containing a benzimidazole ring and an electron-rich pyridine ring was developed, the resulting manganese complex exhibited good activity in C-H oxidation of simple alkanes. In particular, cyclic aliphatic alkanes were transformed into ketones in very good yields (up to 89%) using environmentally benign H2O2 as the terminal oxidant. This protocol was also applied successfully in benzylic C-H oxidation giving the corresponding ketones with very good selectivities. In addition, tertiary C-H bonds oxidation of complex molecules by the manganese complex showed potential utility of assembling alcohol with good selectivity in late-stage chemical synthesis.
      PubDate: 2018-02-09T07:56:16.484165-05:
      DOI: 10.1002/asia.201800068
       
  • Cobalt-Catalyzed C-H Nitration of Indoles Employing a Removable Directing
           Group
    • Authors: Paridhi Saxena; Manmohan Kapur
      Abstract: A mild and efficient C(sp²)-H nitration of 3-substituted indoles, using the economical and non-toxic cobalt nitrate hexahydrate [Co(NO₃)₂.6H₂O] as catalyst and tert-butyl nitrite (TBN) as the nitro source, is being reported. This approach provides a unique methodology involving a site selective C-N bond formation for preparation of C-2 substituted nitro indoles. Utilization of the tBoc as the removable directing group enhances the synthetic utility of the method.
      PubDate: 2018-02-09T06:56:59.315747-05:
      DOI: 10.1002/asia.201800036
       
  • Copper-Catalyzed Heteroarylsilylation of Unactivated Olefins through
           Distal Heteroaryl Migration
    • Authors: Hong Zhang; Xinxin Wu, Qian Zhao, Chen Zhu
      Abstract: Herein we disclose a novel copper-catalyzed protocol for heteroarylsilylation of unactivated olefins. The addition of silyl radical to alkene triggers the subsequent intramolecular heteroaryl migration. Heteroaryls such as benzothiazolyl, thiazolyl, imidazolyl, and pyridyl group showcase the migratory aptitude. A variety of heteroaryl-substituted alkyl silanes are readily generated in synthetically useful yields.
      PubDate: 2018-02-09T04:41:08.142167-05:
      DOI: 10.1002/asia.201800150
       
  • Diazadibora[1.1.1.1]m,p,m,p-cyclophanes: Ambipolar Conjugated Macrocycles
           with Different B–π–N Embedded Patterns
    • Authors: Akihiro Ito; Masashi Uebe, Ryohei Kurata, Soichiro Yano, Hiroyuki Fueno, Takashi Matsumoto
      Abstract: Are different B(boron)–π–N(nitrogen) embedded patterns to bring about significant different (opto)electronic properties for the same macrocyclic molecular backbone' A series of B–π–N-embedded alternate-meta-para-linked cyclophanes 1–3 have been prepared and characterized as a new class of ambipolar π-conjugated B–π–N macrocycles. The answer to the opening question is yes. These macrocycles revealed the intramolecular charge transfer in the oxidized states and the intriguing photophysical proprerties in accordance with the embedded patterns, suggesting the electronic structures are tunable by introducing multiple B–π–N moieties.Three isomers of two-boron-and-two-nitrogen-bridged alternate-meta-para-[14]hetera- cyclophanes show the importance of embedded patterns of B–π–N units in conjugated macrocycles: these isomers display completely different (opto)electronic properties.
      PubDate: 2018-02-09T04:05:39.977611-05:
      DOI: 10.1002/asia.201701717
       
  • Polarity-Dependent Isomerization of an Unsymmetrical Overcrowded Ethylene
           Promoted by Zwitterionic Contribution in the Twisted Isomer
    • Authors: Yasukazu Hirao; Nobuhiro Nagamachi, Katsuma Hosoi, Takashi Kubo
      Abstract: The twisted form of bianthrone is known as a metastable state provided by a photo-induced or thermal-induced isomerization of the folded form, and thus prevents the isolation and the detailed analysis of its electronic structure. In this study, an unsymmetrical bianthrone (2), consisting of the electron-withdrawing anthrone and electron-donating acridane, have been synthesized and shown to exhibit a solvent-polarity-dependent isomerization reaction between the folded and twisted isomers. With increasing the polarity of the solvent, 2 showed an isomerization reaction from the folded form to the twisted form. The stabilization of the twisted isomer in polar solvents can be interpreted as proof of its relatively large zwitterionic character. The DMF solution of 2 displayed paramagnetically-broadened NMR signals from the thermally populated triplet state resulting from rotation of the weakened ethylenic double bond of the twisted isomer.Unsymmetrical overcrowded ethylene: The introduction of asymmetry into the bianthrone structure gives rise to a solvent-polarity-dependent isomerization reaction between the folded form and the twisted form. The twisted isomer can be stabilized in polar solvents due to its relatively large zwitterionic character.
      PubDate: 2018-02-09T04:05:28.283898-05:
      DOI: 10.1002/asia.201701805
       
  • Integrative Self-Sorting: One-Pot Synthesis of a Hetero[4]rotaxane from a
           Daisy-Chain-Containing Hetero[4]pseudorotaxane
    • Authors: Da-Hui Qu; Si-Jia Rao, Qi Zhang, Xu-Hao Ye, Chuan Gao
      Abstract: The structural complexity of mechanically interlocked molecules have been greatly attractive chemist to challenging. In this article, a novel mechanically interlocked molecules daisy-chain-containing hetero[4]rotaxane was efficiently synthesized. In the meantime, a novel integrative self-sorting strategy is demonstrated involving an ABB-type (A for host, dibenzo-24-crown-8 (DB24C8), and B for guest, ammonium salt sites) monomer and the other macrocycle host, benzo-21-crown-7 (B21C7), in which the assembled species in hydrogen-bonding-supported solvent only includes a novel daisy-chain-containing hetero[4]pseudorotaxane. The found self-sorting process involves the integrative recognition between B21C7 macrocycles and carefully designed components simultaneously containing two types of secondary ammonium ions and a host molecule, DB24C8 crown ether. The self-sorting strategy is integrative to undertake self-recognition behavior to form one single species of pseudorotaxane compared with the previous report. This self-sorting system can be used for the efficient one-pot synthesis of a daisy-chain-containing hetero[4]rotaxane in a good yield. The structure of hetero[4]rotaxane was confirmed by 1H NMR spectroscopy and high-resolution electrospray ionization (HR-ESI) mass spectrometry.
      PubDate: 2018-02-09T01:55:37.207578-05:
      DOI: 10.1002/asia.201800011
       
  • Silver-Catalyzed Efficient Synthesis of Oxindoles and Pyrroloindolines via
           α-Aminoalkylation of N-Arylacrylamides with Amino Acid Derivatives
    • Authors: Kyalo Stephen Kanyiva; Sohei Makino, Takanori Shibata
      Abstract: Amino acids are readily available, stable, structurally variable, and inexpensive, making them attractive starting materials for synthesis of complex organic compounds. As shown on the cover picture, α-amino acids were used as precursors for the concise synthesis of oxindoles using silver-catalyzed decarboxylative radical addition to N-aryl acrylamides. The α-aminoalkylation tolerates a broad scope of functional groups often used in organic synthesis. Moreover, the synthesized oxindoles were readily transformed into densely functionalized pyrroloindolines by deprotection and cyclization. More information can be found in the Communication by Kyalo Stephen Kanyiva et al.
      PubDate: 2018-02-07T02:21:32.409117-05:
      DOI: 10.1002/asia.201800100
       
  • Synthesis of Functionalized (η5-Indenyl)rhodium(III) Complexes and Their
           Application to C−H Bond Functionalization
    • Authors: Jyunichi Terasawa; Yu Shibata, Yuki Kimura, Ken Tanaka
      Abstract: Reductive complexation of functionalized benzofulvenes, which are readily prepared from commercially available indenes, with RhCl3 in ethanol affords the corresponding indenyl-rhodium(III) dichlorides bearing various substituents. Thus, the new gate to functionalized indenyl-rhodium(III) complexes, as well as Cp-rhodium(III), is now opened. Furthermore, the thus obtained indenyl-rhodium(III) complexes bearing one ethoxycarbonyl group showed high catalytic activity and regioselectivity toward the oxidative [3+2] annulation of acetanilides with internal alkynes. More information can be found in the Communication by Yu Shibata, Ken Tanaka et al.
      PubDate: 2018-02-07T02:21:22.75993-05:0
      DOI: 10.1002/asia.201800122
       
  • Iron-Catalyzed Aminative Cyclization/Intermolecular Homolytic Aromatic
           Substitution Using Oxime Esters and Simple Arenes
    • Authors: Takuya Shimbayashi; Kazuhiro Okamoto, Kouichi Ohe
      Abstract: HAS type alkylation: An iron-catalyzed intramolecular homolytic aromatic substitution (HAS) reaction in tandem with an intramolecular aminative cyclization of alkene-tethered oxime esters, which is triggered by N−O bond cleavage, is described. Various arenes, including benzene, electron-rich and electron-deficient arenes, and heteroarenes can be employed in the reaction system. Mechanistic studies imply involvement of an alkyl radical intermediate that should undergo arylation by an HAS mechanism. More information can be found in the Communication by Takuya Shimbayashi, Kazuhiro Okamoto, and Kouichi Ohe.
      PubDate: 2018-02-06T07:41:19.36539-05:0
      DOI: 10.1002/asia.201800071
       
  • Synthesis and properties of a decacyclene monoimide and a naphthalimide
           derivative as a three-dimensional acceptor‒donor‒acceptor system
    • Authors: Takeshi Kawase; Yuma Yamamoto, Miu Yoshida, Takuya Morii, Jun-ichi Nishida, Chitoshi Kitamura
      Abstract: A method, which employs Diels‒Alder (DA) cycloadditions of diacenaphtheno[1,2-b;1',2'-d]thiophenes (DAT) with N-alkylacenaphthylene-5,6-dicarboximides (AI), was developed to synthesize decacyclene monoimides (DCMI). The reactions generate the corresponding 1:2 adducts (BAIAs) as major products together with 1:1 adducts (DCMIs). The molecular structure of BAIAb (N-octyl derivative) was unambiguously assigned as the bis-adduct having an endo,endo spatial disposition of the two acenaphthylene-5,6-dicarboximide moieties by using X-ray crystallographic analysis. Relative to that of decacyclene triimide (DCTIa, N-2-ethylhexyl derivative), the analogous N-2-ethylhexyl-substituted mono-adduct DCMIa exhibits a bathochromic shift in its absorption spectrum despite possessing a less delocalized π-electron system. DCMIa does not fluoresce in various organic solvents, while DCTIa emits yellow fluorescence in CH2Cl2 with a low quantum yield (SN). Moreover, DCMIa in CDCl3 displays concentration-dependent 1H-NMR behavior, suggesting that it self-aggregates with an (association constant (Ka) of 193 ± 50 M‒1 at 20 °C. Despite the presence of four bulky t-butyl groups in DCMIa, its Ka value for aggregate formation is comparable to that of DCTIa (495 ± 42 M‒1), which does not contain t-butyl substituents. Spectroscopic studies with the bis-adduct BAIAa (N-2-ethylhexyl derivative) show that it displays remarkable solvatofluorochromism corresponding to an emission maximum shift (ΔλEM) of 100 nm. The results of density functional theory (DFT) calculations on BAIAc (N-methyl derivative) demonstrate that a considerable spatial separation exists between the HOMO and LUMO coefficient distributions, indicating that the ground-to-excited state transition of the novel three-dimensional acceptor‒donor‒acceptor system BAIAa should have intramolecular charge transfer (ICT) character.
      PubDate: 2018-02-06T04:22:36.798588-05:
      DOI: 10.1002/asia.201701668
       
  • Bright photoluminescence of [(CptBu2)2Ce(µ-Cl)]2 - A valuable technique
           for the determination of the oxidation state of cerium
    • Authors: Markus Suta; Nicole Harmgarth, Marcel Kühling, Phil Liebing, Frank T. Edelmann, Claudia Wickleder
      Abstract: The synthesis and photoluminescence properties of the bright yellow organocerium complex [(CptBu2)2Ce(µ-Cl)]2 (CptBu2 = 1,3-di(tert-butyl)cyclopentadienyl) are presented in this paper. This coordination compound exhibits a very efficient photoluminescence in the yellow range with an astonishingly high internal quantum yield of (61 ± 2)% at room temperature. The huge red shift is attributed to the delocalizing ability of the aromatic ligands and the quantum yield makes this compound even competitive to Ce3+-activated LED phosphors in terms of its photoluminescence efficiency. A bridging connection of the two crystallographically independent Ce3+ ions is anticipated as the reason for the very efficient photoluminescence even up to room temperature. The emission spectra are characterized by two bands in the orange spectral range both at 10 K and room temperature that are attributed to the parity-allowed transitions 5d1(2D3/2) 4f1(2F7/2) and 5d1(2D3/2) 4f1(2F5/2) of Ce3+, respectively. The photoluminescence spectra are interpreted in relation to the structure and vibrational modes of the presented coordination compound. The spectra and optical properties indicate that trivalent cerium ions are the dominant species in the ground state, which resolves an often-encountered ambiguity in organocerium compounds. This illustrates that photoluminescence spectroscopy is a versatile tool to elucidate the oxidation state of Ce in such compounds.
      PubDate: 2018-02-06T01:45:20.361937-05:
      DOI: 10.1002/asia.201701818
       
  • Dual-Targeted Selenium Nanoparticles for Synergistic Photothermal Therapy
           and Chemotherapy of Tumor
    • Authors: Xueyang Fang; Chang'e Li, Lan Zheng, Fang Yang, Tianfeng Chen
      Abstract: A combination of chemotherapy and photothermal therapy has emerged as a promising tactic for cancer therapy. However, the intricacy of accurate delivery and the ability to initiate drug release in specific tumor sites remains a challenging puzzle. Hence, to assure the chemotherapeutic drug and photothermal agent to be synchronously delivered to a tumor area to give play to their synergistic effect, the dual-target (RC-12 and PG-6 peptides) functionalized selenium nanoparticles loaded with both doxorubicin (DOX) and indocyanine green (ICG) were designed and successfully synthesized. The as-synthesized nanoparticles exhibited good monodispersity, size stability and consistent spectral characteristics compared with ICG or DOX alone. The nanoparticles underwent self-immolated cleavage with the irradiation of NIR laser and released the loaded drug due to sufficient hyperthermia. Moreover, the internalized nanoparticles triggered intracellular reactive oxygen species (ROS) overproduction to induce cell apoptosis. Taken together, this study provides a sequentially triggered nanosystem to achieve the precise drug delivery by chemo-photothermal combination.
      PubDate: 2018-02-03T11:10:27.686761-05:
      DOI: 10.1002/asia.201800048
       
  • Multicomponent Synthesis of Isoindolinone Frameworks via Rh(III)-Catalysed
           in situ Directing Group Assisted Tandem Oxidative Olefination/Michael
           Addition
    • Authors: Liang Wang; Xi Liu, Jian-biao Liu, Jun Shen, Qun Chen, Ming-yang He
      Abstract: A Rh(III)-catalysed three-component synthesis of isoindolinone frameworks via direct assemblies of benzoyl chlorides, o-aminophenols and activated alkenes has been developed. The process involves in situ generation of o-aminophenol (OAP)-based bidentate directing group (DG), Rh(III)-catalysed tandem ortho C−H olefination and subsequent cyclization via aza-Michael addition. This protocol exhibits good chemoselectivity and functional group tolerance. Computational studies showed that the presence of hydroxyl group on the N-aryl ring could enhance the chemoselectivity of the reaction.
      PubDate: 2018-02-02T08:10:30.921303-05:
      DOI: 10.1002/asia.201800120
       
  • Which one is Bulkier: the 3,5-Dimethylphenyl or the 2,6-Dimethylphenyl
           Group' Development of Size-Complementary Molecular and Macromolecular
           [2]Rotaxanes
    • Authors: Hiroki Sato; Daisuke Aoki, Toshikazu Takata
      Abstract: We developed novel size-complementary molecular and macromolecular rotaxanes using a 2,6-dimethylphenyl terminal as the axle-end-cap group in dibenzo-24-crown-8-ether (DB24C8)-based rotaxanes, where the 2,6-dimethylphenyl group was found to be less bulky than the 3,5-dimethylphenyl group. A series of molecular and macromolecular [2]rotaxanes that bear a 2,6-dimethylphenyl group as the axle-end-cap were synthesized using unsubstituted and fluorine-substituted DB24C8. Base-induced decomposition into their constituent components confirmed the occurrence of deslipping, which supports the size-complementarity of these rotaxanes. The deslipping rate was independent of the axle length but dependent on the DB24C8 substituents. A kinetic study indicated the rate-determining step to be the step that the wheel is getting over the end-cap group, and the deslipping proceeded via a hopping-over mechanism. Finally, the present deslipping behavior was applied to a stimulus-degradable polymer as an example for the versatile utility of this concept in the context of stimulus-responsive materials.
      PubDate: 2018-02-02T03:11:30.835738-05:
      DOI: 10.1002/asia.201800170
       
  • Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16: Strong Nonlinear Optical Response
           in Quaternary Diamond-Like Selenide Networks
    • Authors: Yangwu Guo; Xiaoshuang Li, Kai Feng, Chao Li, Molin Zhou, Yicheng Wu, Jiyong Yao
      Abstract: Two new selenides with diamond-like structures, Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16, were synthesized by a conventional high-temperature solid-state reaction method. They crystallize in the space group Pna21 (No. 33) of the orthorhombic system. Their three-dimensional frameworks consist of corner sharing LiSe4, CdSe4 and MSe4 (M = Ge, Sn) tetrahedra. These two compounds exhibit strong powder second harmonic generation response about 1.2/2.5 times that of the benchmark AgGaS2 at a laser wavelength of 2.09 μm, and also demonstrate type-I phase-matchable behavior. The optical band gaps are determined to be 2.18 and 1.95 eV for Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16 respectively. Furthermore, these two materials exhibit congruent-melting behavior at rather low temperature 985 K and 1060 K respectively, which makes the bulk single crystal growth by the Bridgman-Stockbarger method possible. Our study indicates that these two materials show overall advantages over the traditional IR NLO material CdSe and are promising for practical application.
      PubDate: 2018-02-02T02:41:07.793865-05:
      DOI: 10.1002/asia.201800090
       
  • Self-Assembly of Achiral Shape Amphiphiles into Multi-Walled Nanotubes via
           Helicity-Selective Nucleation and Growth
    • Authors: Li-Jun Ren; Han Wu, Min-Biao Hu, Yu-Han Wei, Yue Lin, Wei Wang
      Abstract: Soft nanotubes are normally constructed from chiral amphiphiles through helical self-assembly. Yet, how to self-assemble achiral molecules into nanotubes is still a challenge. Here, we report the nanotube construction with achiral shape amphiphiles through helical self-assembly and also unravel the formation mechanisms. The amphiphiles have a dumbbell shape and are composed by covalently linking three achiral moieties together: two unlike clusters and an organic tether. Difference in polarity between the unlike clusters drives the amphiphiles to self-assemble into single- and multi-walled nanotubes as well as intermediates. The key intermediates unravel the self-assembly mechanism of helicity-selective nucleation and growth. Meanwhile, direct visualization of the individual clusters in the ribbons displays a two-dimensional deformed hexagonal lattice. Thus we speculate that it is the lattice deformation that creates anisotropic tension along different directions of the ribbon which further results in the formation of helical ribbons towards nanotubes by amphiphiles.
      PubDate: 2018-02-02T02:40:36.526473-05:
      DOI: 10.1002/asia.201800005
       
  • Synthesis of N-doped Mesoporous Carbon Nanorods through Nano-confined
           Reaction: High Performance Catalyst Support for Hydrogenation of Phenol
           Derivatives
    • Authors: Xueteng Liu; Fei Pang, Jianping Ge
      Abstract: Traditional hard-template method for the preparation of mesoporous carbon structures has been well developed, but it may have difficulty in complete filling of organic precursors in ordered mesochannels and exact replication of the templates. Here, mesoporous carbon nanorods (meso-CNRs) are synthesized through thermal condensation of furfuryl alcohol followed by the nano-confined decomposition of polyfurfuryl alcohol in silica nanotubes (SiO2 NTs) with porous shells. Limited and slow releasing of gaseous water through the porous shells and finite polyfurfuryl precursor inside silica nanotubes are responsible for the formation of mesoporous structures. Nitrogen can be doped to the meso-CNRs by adding guanidine hydrochloride to the precursors. The nitrogen dopant not only stabilize the ultrasmall and active Pd nanocatalyst in meso-CNRs but also increase the electron density of Pd and accelerate the dissociation of H2, both of which increase the catalytic activity of Pd catalyst in hydrogenation reactions.
      PubDate: 2018-02-02T01:05:55.745153-05:
      DOI: 10.1002/asia.201800112
       
  • Upconversion in Nanostructured Materials: From Optical Tuning to
           Biomedical Applications
    • Authors: Tianying Sun; Fujin Ai, Guangyu Zhu, Feng Wang
      Abstract: The front cover illustrates a core−shell upconversion nanoparticle travelling in the blood stream. Under excitation of near-infrared light, the nanoparticle shows tunable emissions in the visible and ultraviolet region of the spectrum, allowing for a variety of biomedical applications such as sensitive biodetection and deep-tissue imaging. The advances of upconversion research in the past few years are largely attributed to the establishment of nanostructural engineering as a general strategy for unprecedented optical tuning. Herein, recent progress in controlling upconversion in nanostructured materials and utilizing upconversion processes for emerging biomedical applications are discussed. More information can be found in the Focus Review by Guangyu Zhu, Feng Wang et al.
      PubDate: 2018-02-01T07:30:43.59877-05:0
      DOI: 10.1002/asia.201800117
       
  • A Spin-Active, Electrochromic, Solvent-Free Molecular Liquid Based on
           Double-Decker Lutetium Phthalocyanine Bearing Long Branched Alkyl Chains
    • Authors: Agnieszka Zielinska; Atsuro Takai, Hiroya Sakurai, Akinori Saeki, Marcin Leonowicz, Takashi Nakanishi
      Abstract: Synthesis and characterization of a novel, multifunctional, solvent-free room-temperature liquid based on alkylated double-decker lutetium (III) phthalocyanine (Pc₂Lu) are described. Lowering of the melting point and viscosity of intrinsically solid Pc₂Lu compounds has been achieved through the attachment of flexible, bulky, and long branched-alkyl chains, i.e. 2-octyldodecyl, to the periphery of the Pc₂Lu unit. The embedded Pc₂Lu unit maintains its inherent molecular functions, such as spin-active nature and electrochromic behavior in the liquid state. Comparison of the properties with a solid-like Pc₂Lu derivative, functionalized with shorter alkyl chains, i.e. 2-ethylhexyl, underlines the importance of the hampering effect on the π-π interactions of neighboring Pc₂Lu molecules by bulkier and longer branched-alkyl chains. This study could possibly pave the way for novel multifunctional liquids whose spin-activities are associated with their rheological or optoelectronic properties.
      PubDate: 2018-01-31T12:03:50.093331-05:
      DOI: 10.1002/asia.201800175
       
  • Tuning of thermoresponsivity of a poly(2-alkyl-2-oxazoline) block
           copolymer by interaction with surface active and chaotropic
           metallacarborane anion
    • Authors: Vladimir Ďorďovič; Bart Verbraeken, Richard Hoogenboom, Sami Kereïche, Pavel Matějíček, Mariusz Uchman
      Abstract: In this study we prepared thermoresponsive nanoparticles based on interaction of metallacarboranes, bulky chaotropic and surface active anions, and poly(2-alkyl-2-oxazoline) block copolymers. Recently, the great potential of metallacarboranes have been recognized in biomedicine and many delivery nanosystems have been proposed. However, none of them have thermoresponsive character. Therefore, we synthesized a thermoresponsive block copolymer poly(2-methyl-2-oxazoline)-block-poly(2-n-propyl-2-oxazoline), PMeOx-PPrOx, to encapsulate metallacarboranes. Light scattering, nuclear magnetic resonance spectroscopy, isothermal titration calorimetry and cryogenic transmission electron microscopy were used to characterize all the solutions of the formed nanoparticles. The cloud point temperature (TCP) of the block copolymer was observed at 30 °C and above this temperature polymeric micelles are formed. Sodium cobalt bis(dicarbollide), COSAN, was found to interact with both polymeric segments. Depending on COSAN concentration, this affinity influenced the phase transition of thermoresponsive PPrOx block. The TCP is shifted to lower values at lower COSAN content. At higher concentrations of COSAN, the hybrid nanoparticles are fragmented into relatively small pieces. This system is also thermoresponsive, whereby the temperature increase leads to higher polymer mobility and COSAN release.
      PubDate: 2018-01-31T06:05:50.432532-05:
      DOI: 10.1002/asia.201701720
       
  • Energy Transfer in Dye-coupled Lanthanide-doped Nanoparticles: from Design
           to Application
    • Authors: Juan Wang; Renren Deng
      Abstract: Surface modification with organic dye molecules have been evidenced as a useful strategy to manipulate the optical properties of lanthanide-doped nanoparticles (LnNPs). It enables energy transfer between dyes and LnNPs, which provides unprecedented possibilities to gain new optical phenomena from the dye-LnNPs composite systems. This has led to a wide range of emerging applications such as biosensing, drug delivery, gene targeting, information storage, and photon energy conversion. In this review, the mechanism of energy transfer and the structural dependent energy transfer properties in dye-coupled LnNPs are discussed. The design strategies for achieving effective dye-LnNPs functionalization are presented. The recent advances of these composite nanomaterials in biomedicine and energy conversion applications are highlighted.
      PubDate: 2018-01-30T03:32:14.803992-05:
      DOI: 10.1002/asia.201701817
       
  • Development of Pseudomonas aeruginosa Lectin LecA Inhibitors using
           Bivalent Galactosides Supported on Polyproline Peptide Scaffolds
    • Authors: Shao-Feng Huang; Cin-Hao Lin, Yu-Tsung Lai, Chia-Lung Tsai, Ting-Jen Rachel Cheng, Sheng-Kai Wang
      Abstract: LecA is a galactose-binding tetrameric lectin from Pseudomonas aeruginosa involved in infection and biofilm formation. The emergent antibiotic resistance of P. aeruginosa has made LecA a promising pharmaceutical target to treat such infections. To develop LecA inhibitors, we exploit the unique helical structure of polyproline peptides to create a scaffold that controls the galactoside positions to fit their binding sites on LecA. With a modular scaffold design, both the galactoside ligands and the inter-ligand distance can be altered conveniently. We prepared scaffolds with spacings of 9, 18, 27 and 36 Å for ligand conjugation and found that glycopeptides with galactosides ligands three helical turns (27 Å) apart best fit LecA. In addition, we tested different galactose derivatives on the selected scaffold (27 Å) to improve binding avidity to LecA. The results validate a new multivalent scaffold design and provide useful information for LecA inhibitor development.
      PubDate: 2018-01-29T23:55:55.113143-05:
      DOI: 10.1002/asia.201701724
       
  • Tandem Radical Cyclization for the Construction of Difluoro-Containing
           Oxindoles and Quinoline-2,4-diones
    • Authors: Fangwei Ding; Yuanding Fang, Yanqiu Jiang, Kaifeng Lin, Lei Shi
      Abstract: Cu catalyzed direct difluoromethylation of activated alkenes through a difluoromethyl radical addition/cyclization to afford difluorinated oxindoles and quinoline-2,4-diones has been developed. This method provides convenient access to a variety of oxindoles and quinoline-2,4-diones under mild conditions via a proposed tandem radical cyclization process, which tolerated various functional groups well. What's more, a facile method to construct diverse difluorinated quinoline-2,4-diones was presented by visible-light photoredox catalysis under mild conditions.
      PubDate: 2018-01-29T22:25:45.70599-05:0
      DOI: 10.1002/asia.201701780
       
  • Solution-Processable Balanced Ambipolar Field-Effect Transistors Based on
           Carbonyl Regulated Copolymers
    • Authors: Chengdong Yang; Renren Fang, Xiongfa Yang, Ru Chen, Jianhua Gao, Hanghong Fan, Hongxiang Li, Wenping Hu
      Abstract: It is very important to develop the ambipolar field effect transistors for constructing complementary-like circuits. In order to obtain balanced hole and electron transport properties, one of the key issues is to regulate the energy levels of the frontier orbitals of the semiconductor materials by structural tailoring thus matching well with the electrode Fermi levels. Five conjugated copolymers were synthesized and exhibited low lowest unoccupied molecular orbital (LUMO) energy levels and narrow band gaps on account of the strong electron-withdrawing effect of carbonyl group. The polymer thin films transistors were prepared by solution-method and exhibited high and balanced hole and electron mobility up to 0.46 cm2V-1s-1, which suggest that these copolymers are promising ambipolar semiconductor materials.
      PubDate: 2018-01-29T22:25:36.909523-05:
      DOI: 10.1002/asia.201701800
       
  • Defect-Free Mixed-Matrix Membranes with Hydrophilic Metal-Organic
           Polyhedra for Efficient CO2 Separation
    • Authors: Yang No Yun; Muhammad Sohail, Jong-Ho Moon, Tae Woo Kim, Kyeng Min Park, Dong Hyuk Chun, Young Cheol Park, Chul-Hee Cho, Hyunuk Kim
      Abstract: Defect-free mixed-matrix membranes (MMMs) were prepared by incorporating hydrophilic metal-organic polyhedra (MOPs) into cross-linked polyethylene oxide (XLPEO) for efficient CO₂ separation. Hydrophilic MOPs with triethylene glycol pendant groups, which were assembled by 5-tri(ethylene glycol) monomethyl ether isophthalic acid and Cu(II) ions, were uniformly dispersed in XLPEO without particle agglomeration. Comparing with conventional neat XLPEO, the homogenous dispersion of EG₃-MOPs in XLPEO enhanced CO₂ permeability of MMMs. Upon increasing the amount of EG₃-MOPs, the membrane performance such as CO₂/N₂ selectivity was steadily improved because of unsaturated Cu(II) sites at paddle-wheel units, which was confirmed by Cu K-edge XANES and TPD analysis. Therefore, such defect-free MMMs with unsaturated metal sites would contribute to enhance CO₂ separation performance.
      PubDate: 2018-01-29T08:26:24.861377-05:
      DOI: 10.1002/asia.201701647
       
  • Density Functional Theory Mechanistic Study of Boron-Catalyzed
           N-Alkylation of Amines with HCO2H: HCO2H Activation via Silylation
           Reaction
    • Authors: Pan Du; Jiyang Zhao
      Abstract: New methodology for alkylation of amines is an intriguing issue in both academia and industry. Recently, several groups reported the metal-free B(C6F5)3-catalyzed N-alkylation of amines. But the mechanistic details of these important reactions are unclear. Herein, a computational study was performed to elucidate the mechanism of the N-alkylation of amines with formic acid catalyzed by Lewis acid B(C6F5)3 in the presence of hydrosilane. We found that the reaction is started with the activation of formic acid via a novel model. Then, the high electrophilicity of the C centre of the formic acid unit and the nucleophilic character of the amine result in the C-N coupling reaction. Finally, two sequential silyl group and H- transfer steps occur to generate the final product. Based on comparing the reaction barrier and indole hydrogenation, our mechanism is more favourable than that proposed by the group of Yu and Fu.
      PubDate: 2018-01-29T05:20:37.908113-05:
      DOI: 10.1002/asia.201701607
       
  • Near Infrared BODIPY for bioimaging and photothermal therapy
    • Authors: yang liu; nan song, li chen, shi liu, zhigang xie
      Abstract: It is challenging to develop robust photothermal agents with near-infrared (NIR) imaging simultaneously. In this work, a new photothermal agent was designed and synthesized based on aza-boron-dipyrromethene (aza-BDP). The aza-BDP possesses excellent photostability and higher photothermal conversion efficiency (50%) under NIR laser irradiation. When the photothermal effects were utilized for tumor inhibition, long term stable fluorescence was observed in living animals. The photothermal treatment can efficiently suppress the tumor growth, which was evidenced by in vitro and in vivo experiments. Meanwhile, the NIR emission can be detected by imaging system and achieved therapeutic self-monitoring under the guidance of NIR imaging. This work highlights the potential of rational design of molecular structures for desired functional and applications.
      PubDate: 2018-01-28T21:55:24.040174-05:
      DOI: 10.1002/asia.201701727
       
  • Recent Advance between Supramolecular Gels and Catalysis
    • Authors: Tao Tu; Haibo Zhu
      Abstract: In the past two decades, supramolecular gels have attracted significant attentions from scientists in diverse research fields and have been fully developed. This review mainly focuses on the significant achievements between supramolecular gels and catalysis. Firstly, by incorporating kinds of catalytic sites and active organic functional groups into gelator molecules, supramolecular gels are considered as a novel matrix for catalysis. In addition, the rational-designed supramolecular gels also provide a variety of templates for accessing metal nanocomposites, which may function as catalysts and exhibit high activities in diverse catalytic transformations. Finally, as a new kind of biomaterials, supramolecular gels formed in situ via self-assembly triggered by the catalytic transformations are also covered in this review.
      PubDate: 2018-01-27T14:20:27.709235-05:
      DOI: 10.1002/asia.201800017
       
  • CF3-Inspired Synthesis of Air-Tolerant 9-Phosphaanthracenes Featuring
           Fluorescence and Crystalline Polymorphs
    • Authors: Shigekazu Ito; Kota Koshino, Koichi Mikami
      Abstract: 9-Phosphaanthracene (dibenzo[b,e]phosphorin, acridophosphine) has been of interest as one of the heavier acenes. In this paper, we demonstrate an efficient synthetic process providing air-tolerant 1,8-bis(trifluoromethyl)-9-phosphaanthracenes. The sterically encumbered and electron-withdrawing trifluoromethyl (CF3) groups were quite advantageous not only to stabilize the intrinsically unstable heavier unsaturated phosphorus atom but also to facilitate construction of the phosphinine skeleton based on the putative increase of aromaticity. The isolable 9-phosphaanthracenes were effective to characterize the fluorescence functionality and the planar heteroanthracene framework. The crystal structures of 9-phosphaanthracenes are remarkably dependent on the aryl substituents at the 10-position; The anthryl-substituted 9-phosphaanthracene showed the unique polymorphs inducing different colour of crystals.
      PubDate: 2018-01-27T02:45:24.434581-05:
      DOI: 10.1002/asia.201701669
       
  • Palladium-Catalyzed Reductive Coupling Reaction of Terminal Alkynes with
           Aryl Iodides Utilizing Hafnocene Difluoride as a Hafnium Hydride Precursor
           Leading to trans-Alkenes
    • Authors: Norio Sakai; Keita Takahashi, Yohei Ogiwara
      Abstract: Herein, we describe a reductive cross-coupling of alkynes and aryl iodides using a novel catalytic system composed of a catalytic amount of palladium dichloride and a promoter precursor, hafnocene difluoride (Cp2HfF2), in the presence of a mild reducing reagent, a hydrosilane, leading to a one-pot preparation of trans-alkenes. In this process, a series of coupling reactions efficiently proceeds via the following three steps: (i) an initial formation of hafnocene hydride from hafnocene difluoride and a hydrosilane, (ii) a subsequent hydrohafnation toward alkynes, and (iii) a final transmetalation of the alkenyl hafnium species to a palladium complex. This reductive coupling could be chemoselectively applied to the preparation of trans-alkenes with various functional groups, such as an alkyl group, a halogen, an ester, a nitro group, a heterocycle, a boronic ester, and an internal alkyne.
      PubDate: 2018-01-26T10:45:31.709615-05:
      DOI: 10.1002/asia.201701775
       
  • Motion Induced Change in Emission as an Effective Strategy for Ratiometric
           Probing of Human Serum Albumin and Trypsin in Biological Fluids
    • Authors: Nilanjan Dey; Basudeb Maji, Santanu Bhattacharya
      Abstract: We report a highly luminescent pH sensitive, thermo-reversible nanoaggregate material in pure aqueous medium via self-agglomeration of carbazole-based amphiphiles. The self-assembly process restricts the intramolecular motions of the molecules and induces a change in emission signal from blue to cyan (AIE effect). A similar kind of ratiometric response is also observed in presence of human serum albumin (HSA). However, here the molecular motion of the flexible fluorescnce probe is restricted by its embdding microenvironment, not aggregation (MICE effect). Moreover, the probe shows fairly high selectivity towards HSA over other serum albumin proteins. Our carbazole-based fluorescence probes are a unique example, where ratiometric sensing of HSA is achieved solely by involving reversible noncovalent interactions. Considering the high significance of HSA in clinical diagnosis, a wide range of biological fluids, such as human urine, saliva, and plasma have been screened for analyzing HSA contents. In addition to this, the present system is employed for detection of trypsin at sub-nanomolar concentration via digestion of HSA
      PubDate: 2018-01-24T22:08:37.064891-05:
      DOI: 10.1002/asia.201701795
       
  • Synthesis of Two-Electron Bimetallic Cu-Ag and Cu-Au Clusters by using
           [Cu13(S2CNnBu2)6(C≡CPh)4]+ as a Template
    • Authors: Rhone P. Brocha Silalahi; Kiran Kumarvarma Chakrahari, Jian-Hong Liao, Samia Kahlal, Yu-Chiao Liu, Ming-Hsi Chiang, Jean-Yves Saillard, Chen-Wei Liu
      Abstract: Atomically precise Cu-rich bimetallic clusters have been synthesized by adopting a galvanic exchange strategy. [Cu@Cu12(S2CNnBu2)6(C≡CPh)4]+ (1) was used as a template to generate compositionally uniform clusters [M@Cu12(S2CNnBu2)6 (C≡CPh)4]+, where M = Ag (2), Au (3). Structures of 1, 2 and 3 were determined by single crystal X-ray diffraction and the results were supported by ESI-mass spectrometry. The anatomies of clusters 1-3 are very similar, with a centred cuboctahedral cationic core that is surrounded by six di-butyldithiocarbamate (dtc) and four phenylacetylide ligands. The doped Ag and Au atoms were found to preferentially occupy the centre of the 13-atom cuboctahedral core. Experimental and theoretical analysis of the synthesized clusters revealed that both Ag and Au doping result in significant changes in cluster stability, optical characteristics and enhancement in luminescence properties.
      PubDate: 2018-01-24T02:20:38.367834-05:
      DOI: 10.1002/asia.201701753
       
  • Achieving remarkable performances towards ethylene glycol electrooxidation
           based on pentangle-like PtCu nanocatalysts
    • Authors: Hui Xu; Chaofan Liu, Pingping Song, Jin Wang, Fei Gao, Yangping Zhang, Yukihide Shiraishi, Junwei Di, Yukou Du
      Abstract: The research of active and stable electrocatalysts toward liquid fuel oxidation reaction is of great significance for the large-scale commercialization of fuel cells. Although explosive efforts have been devoted to pursuing high-performance nanocatalysts for fuel cells, both the high cost and sluggish reaction kinetics have been two major drawbacks limited its commercial development. In this regard, we demonstrated a facile solvothermal method for the syntheses of an advanced class of PtCu nanocatalysts with unique pentangle-like. By combining the merits of high surface active area, as well as the synergistic and electronic effects, the as-prepared pentangle-like Pt3Cu nanocatalysts showed superior electrocatalytic activity towards ethylene glycol oxidation with the mass and specific activities of 5162.6 mA mg-1 and 9.7 mA cm-2, that ∼ 5.0 and ∼ 5.1 times higher than the commercial Pt/C, respectively. More significantly, the Pt3Cu pentangle also exhibited excellent long-term stability with less activity decay and negligible change in structure after 500 cycles, showing a novel class of anode catalysts for fuel cells and beyond.
      PubDate: 2018-01-23T09:42:20.761935-05:
      DOI: 10.1002/asia.201800029
       
  • Highly sensitive bioluminescent probe for thiol detection in living cells
    • Authors: Mayu Hemmi; Yuma Ikeda, Yutaka Shindo, Takahiro Nakajima, Shigeru Nishiyama, Kotaro Oka, Moritoshi Sato, Yuki Hiruta, Daniel Citterio, Koji Suzuki
      Abstract: The sensitive detection of thiols including glutathione and cysteine is desirable due to their roles as indispensable biomolecules in maintaining intracellular biological redox homeostasis. Herein, we report the design and synthesis of SEluc-1 (Sulfinate Ester Luciferin), a chemoselective probe exhibiting ratiometric and turn-on response towards thiols selectively in fluorescence and bioluminescence, respectively. The probe, which was designed based on the "caged" luciferin strategy, displays excellent selectivity, high S/N ratio (>240 in the case of bioluminescence), and a biologically relevant limit of detection (LOD, 80 nM for cysteine), which are all desirable traits for a sensitive bioluminescent sensor. SEluc-1 was further applied to fluorescence imaging of thiol activity in living human cervical cancer HeLa cell cultures, and was successfully able to detect fluctuations in thiol concentrations induced by oxidative stress in a bioluminescent assay utilizing African green monkey fibroblast COS-7 cells and human breast adenocarcinoma MCF-7 cells.
      PubDate: 2018-01-23T02:05:36.076271-05:
      DOI: 10.1002/asia.201701774
       
  • [(18-crown-6)K][Fe(1)Cl(1)4]0.5[Fe(2)Cl(2)4]0.5: A Multifunctional
           Molecular Switch of Dielectric, Conductivity and Magnetism
    • Authors: Yuan-Bo Tong; Zheng-Fang Tian, Hai-Bao Duan, Zhong-Peng Zhu, Wei He, Tian-Yu Hong, Gui Yu, Yu-Jian He, Jing-Kui YANG
      Abstract: Multifunctional materials that exhibit different physical properties in a single phase have potential for use in multifunctional devices. Herein, we reported an organic-inorganic hybrid compound [(18-crown-6)K][Fe(1)Cl(1)4]0.5[Fe(2)Cl(2)4]0.5 (1) by incorporating KCl and FeCl3 into the 18-crown-6 molecular which acts as a host of the six O atoms affording lone-pair electrons to anchor the guest potassium cation, and [FeCl4]- as a counter ion for charge balance to construct a complex salt. This salt exhibited a one-step reversible structural transformation to give two separate high and low temperature phases at 373 K, which was confirmed by systematic characterizations including differential scanning calorimetry (DSC) measurements, variable-temperature structural analyses, and dielectric, impedance, variable-temperature magnetic susceptibility measurements. Interestingly, the structural transformation was coupled to both hysteretic dielectric phase transition, conductivity switch and magnetic phase transition at 373 K. This novel result gives an idea for designing a new type of phase-transition materials harbouring technologically important magnetic, conductivity and dielectric properties.
      PubDate: 2018-01-22T03:20:42.135515-05:
      DOI: 10.1002/asia.201701794
       
  • Amorphous Materials for Enhanced Localized Surface Plasmon Resonances
    • Authors: Chuanhui Zhu; Qun Xu
      Abstract: The discovery of localized surface plasmon resonances (LSPR) in semiconductor nanocrystals has initiated a new field in plasmonics. And plasmonic nanocrystals of crystal materials have gained rapid development in the past years with a class of materials with unique photoelectronic properties. Present now a growing number of amorphous plasmonic materials are steadily capturing scientific interest of people, though only a few are well-characterized. Here, we focus on the recent development in state-of-the art experiments, and explore the vast library of plasmonic properties in amorphous materials, including their application fields and optical spectral range. Taken together, the growing regime of amorphous material plasmonics offers enticing avenues for harnessing light-matter interactions from the visible to terahertz region, with new optical manipulation beyond what can be accomplished using traditional crystal materials.
      PubDate: 2018-01-19T03:31:01.473864-05:
      DOI: 10.1002/asia.201701722
       
  • [CH3NH3]4Ga4SbS9S0.28O0.72H: A Three-Dimensionally Open-Framework
           Heterometallic Chalcogenidoantimonate Exhibiting Ni2+ Ion-Exchange
           Property
    • Authors: Bo Zhang; Wei-An Li, Yi-Yu Liao, Chen Zhang, Mei-Ling Feng, Xiao-Ying Huang
      Abstract: An open-framework chalcogenidoantimonate, namely, [CH3NH3]4Ga4SbS9S0.28O0.72H (1), has been solvothermally synthesized and structurally characterized. Interestingly, 1 showed Ni2+ ion-exchange properties and wide pH resistance, with a maximum exchange capacity of 76.9 mg/g. To the best of our knowledge, this is the first example of amine-directed three-dimensional (3D) heterometallic chalcogenidometalates for the highly selective Ni2+ ion capture with the high distribution coefficient (Kd = 1.65 × 105 mL/g).
      PubDate: 2018-01-18T10:55:23.933194-05:
      DOI: 10.1002/asia.201701763
       
  • Ruthenium Catalyzed Aerobic Oxidation of Amines
    • Authors: Debabrata Maiti; Goutam Kumar Lahiri, Ritwika Ray, Arijit Singha Hazari
      Abstract: Amine oxidation is one of the fundamental reactions in organic synthesis since it leads to a variety of value-added products like oximes, nitriles, imines and amides among many others. These products comprise the key N-containing building blocks in modern chemical industry, and such transformations when achieved in presence of molecular oxygen without using stoichiometric oxidants, are much preferred since they circumvent the production of unwanted wastes. In parallel, versatility of ruthenium catalysts in various oxidative transformations is well-documented. Herein, the review focuses on aerobic oxidation of amines using ruthenium catalysts in specific and highlights the major achievements in this direction and challenges that still need to be addressed.
      PubDate: 2018-01-18T09:00:47.840675-05:
      DOI: 10.1002/asia.201701748
       
  • Synthesis of Histidine-Containing Oligopeptides via Histidine-Promoted
           Peptide Ligation
    • Authors: Kai-Jin Huang; Yi-Chen Huang, Yuya Angel Lin
      Abstract: Histidine-containing peptides are valuable therapeutic agents for treatment of neurodegenerative diseases. However, the synthesis of histidine-containing peptides is not trivial due to the potential of imidazole sidechain of histidine to act as a nucleophile if unprotected. A peptide ligation method utilizing the imidazole sidechain of histidine has been developed. The key imidazolate intermediate that acts as an internal acyl transfer catalyst during ligation is generated by deprotonation. Transesterification with amino acids or peptides tethered with C-terminal thioester followed by N to N acyl shifts led to the final ligated products. A range of histidine-containing dipeptides could be synthesized in moderate to good yields via this method without protecting the imidazole sidechain. The protocol was further extended to tripeptide synthesis via a long-range N to N acyl transfer, and tetrapeptide synthesis.
      PubDate: 2018-01-18T08:25:24.773899-05:
      DOI: 10.1002/asia.201701802
       
  • Welcome to the New Editorial Board Members
    • Abstract: We warmly welcome our new Editorial Board members Matthias Bickelhaupt, Sally Brooker, Xiaoming Feng, Mikiko Sodeoka, and Takafumi Ueno.
      PubDate: 2018-01-18T06:45:40.960965-05:
      DOI: 10.1002/asia.201800081
       
  • A self-growing strategy for large-scale crystal assembly tubes
    • Authors: Huizeng Li; Mingzhu Li, Qiang Yang, Xiaoli Sun, Bo Guan, Yanlin Song
      Abstract: Assembled tubular materials have attracted widespread attention due to their potential applications in catalysis, bionics, and optic-electronics. Many versatile methods, including template-assistance and self-assembly, have been developed for tubular materials fabrication. Here we demonstrate a self-growing strategy to prepare large-scale crystal assembly tubes. Addition of the template and the need for the sophisticated equipment are avoided with this method. The sidewall of the tubes composes of a layer of polyhedral crystals that are connected together through grain coalescence. We demonstrate that the assembled tubular structure is obtained by the synergetic effect of the passivation layer and the dissolution-recrystallization process. This facile one-step strategy and the formation mechanism will offer guidance for fabrication of new superstructures.
      PubDate: 2018-01-18T04:25:35.530983-05:
      DOI: 10.1002/asia.201800044
       
  • Supramolecular Gels Derived from the Salts of Variously substituted
           Phenylacetic Acid and Dicyclohexyl Amine: Design, Synthesis, Structures
           and Dye Adsorption
    • Authors: Parthasarathi Dastidar; Rajdip Roy, Tapas Kumar Adalder
      Abstract: A well-studied supramolecular synthon namely secondary ammonium monocarboxylate (SAM) was exploited to generate a new series of organic salts derived from variously substituted phenylacetic acid (PA) and dicyclohexyl amine (DCA) as potential low molecular weight gelators (LMWGs). As much as 25% of the SAM salts under study were gelators. The gels were characterized by rheology and the morphology of the gel networks was studied by high resolution electron microscopy. Single crystal and powder X-ray diffraction data were employed to study structure-property (gelation) correlation. One of the gels could adsorb a hydrophobic dye (Nile red) more efficiently than a hydrophilic dye (Calcein) from DMSO which might provide useful clue towards developing stain removing gels.
      PubDate: 2018-01-18T00:55:53.404765-05:
      DOI: 10.1002/asia.201701632
       
  • Different Atomic Terminations Associated Photocatalytic Nitrogen Fixation
           of Bismuth Oxybromide: A First Principles Study
    • Authors: Hongxian Liu; Zhenxing Fang, Yongfei Su, Yuanli Suo, Shuping Huang, Yongfan Zhang, Kaining Ding
      Abstract: We have systematically investigated the electronic structures and activation capacities of BiOBr {001} facets with different atomic terminations by means of DFT methods. Our calculations reveal that oxygen vacancies (OVs) give a significant boost in band edges of the O-terminated BiOBr {001} facets, and excess electrons induced by OVs could exceed the reduction potentials of high-energy N2 intermediates. Interestingly, the Bi-terminated BiOBr {001} facets may be good candidates for photocatalytic nitrogen fixation due to the stronger activation ability of N2 molecules comparing with O-terminated BiOBr {001} facets with OVs. Moreover, the Bi-terminated BiOBr {001} facets may tend to yield NH3 instead of N2H4.
      PubDate: 2018-01-17T13:25:22.047285-05:
      DOI: 10.1002/asia.201701670
       
  • Bifunctional fluorescent probe for sequential sensing thiols and primary
           aliphatic amines in distinct fluorescence channels
    • Authors: Lingliang Long; Meiyu Huang, Ning Wang, Xiangqi Yuan, Siyu Cao, Aihua Gong, Kun Wang
      Abstract: Thiols and primary aliphatic amines (PAA) are ubiquitous and extremely important species in biological system. They have performed significant interplaying roles in complex biological events. A single fluorescent probe differentiating both thiol and PAA can contribute to understanding the intrinsic inter-relationship of thiols and PAA in biological processes. Herein, we rationally constructed the first fluorescent probe that can respond to thiols and PAA in different fluorescence channels. The probe exhibited high selectivity and sensitivity to thiols and PAA. In addition, it displayed sequential sensing ability when the thiols and PAA were coexisted. The application experiment indicated that the probe can be used for sensing thiols and PAA in human blood serum. Moreover, the fluorescence imaging of endogenous thiols and PAA as well as antihypertensive drugs captopril and amlodipine in living cells were successfully conducted.
      PubDate: 2018-01-17T01:50:25.162552-05:
      DOI: 10.1002/asia.201701733
       
  • Integrating TEMPO or Its Analogues with Visible Light Photocatalysis
    • Authors: Xianjun Lang; Jincai Zhao
      Abstract: Visible light has risen to be a very important facilitator for selective radical reactions enabled by well-cognized photocatalysts. The renaissance of visible light photocatalysis on this matter partly relies on integrating it with other area of catalysis. In parallel, TEMPO, a quintessential persistent radical, has a wide range of uses due to its exceptional redox behavior, giving rise to its latest prominence in catalysis. Therefore, integrating the catalysis of TEMPO with photocatalysis to carry out visible light-induced selective reactions becomes very convenient marriage of merits. In this context, the integration of different types of photocatalysts including metal complexes, metal-free organic dyes and semiconductors with TEMPO for outstanding organic transformations will be summarized separately. To further expand the catalytic repertoire, the integration of TEMPOH analogues such as NHPI (N-hydroxyphthalimide) or NHS (N-hydroxysuccinimide) with photocatalysis will also be discussed in different sections. Hopefully, these advances could pave the way for more breakthroughs by integrating TEMPO and its analogues with photocatalysis, leading to a valuable blueprint for visible light-induced selective organic transformations.
      PubDate: 2018-01-16T07:55:33.80113-05:0
      DOI: 10.1002/asia.201701765
       
  • Synthesis of Functionalized (η5-Indenyl)rhodium(III) Complexes and Their
           Application to C-H Bond Functionalization
    • Authors: Jyunichi Terasawa; Yu Shibata, Yuki Kimura, Ken Tanaka
      Abstract: It has been established that reductive complexation of functionalized benzofulvenes, which are readily prepared from commercially available indene and 2-methylindene, with RhCl3 in ethanol affords the corresponding indenyl-rhodium(III) dichlorides bearing substituents at the 1- (H or CO2Et), 2- (H or Me), and 3- [CH2Ph or CH2(2-MeOC6H4)] positions. The thus obtained indenyl-rhodium(III) complexes bearing one ethoxycarbonyl group showed higher thermal stability and regioselectivity than our previously reported CpERhIII complex toward the oxidative [3+2] annulation of acetanilides with internal alkynes.
      PubDate: 2018-01-16T05:51:11.818887-05:
      DOI: 10.1002/asia.201701716
       
  • Prussian Blue Derived FeP Nanoparticles in Porous Graphene Aerogel as
           Efficient Electrocatalysts for Hydrogen Evolution Reaction
    • Authors: Narendra Kumar Alam Venugopal; Shuli Yin, Yinghao Li, Hairong Xue, You Xu, Xiaonian Li, Hongjing Wang, Liang Wang
      Abstract: Tailoring of new hydrogen evolution reaction (HER) electrocatalyst with earth abundant elements is important for large scale water splitting and hydrogen production. In this work, we present a simple synthetic method for incorporating iron phosphide (FeP) particles into three-dimensional (3D) porous graphene aerogel (GA) structure. The FeP formed in porous 3D GA (FeP/GA) is derived from electroactive Fe hexacyanoferrate (FeHCF). The advantage of incorporating FeP, in the porous 3D graphene network enables high accessibility for HER. As synthesized FeP/GA catalyst shows good electrocatalytic activity for HER in both acidic and alkaline solutions. The developed method can be useful for synthesizing metal hexacyanoferrate derived mono/bimetal phosphide catalyst in porous 3D graphene aerogels.
      PubDate: 2018-01-16T04:22:21.725789-05:
      DOI: 10.1002/asia.201701616
       
  • Pomegranate-Structured Silica/Sulfur Composite Cathodes for High
           Performance Lithium-Sulfur Batteries
    • Authors: Soojin Park; Sinho Choi, Dawei Su, Myoungsoo Shin, Guoxiu Wang
      Abstract: Porous materials have many structural advantages for energy storage and conversion devices such as rechargeable batteries, supercapacitors, and fuel cells. When applied as a host material in lithium-sulfur batteries, porous silica materials with a pomegranate-like architecture can not only act as a buffer matrix for accommodating a large volume change of sulfur, but also suppress the polysulfide shuttle effect. The porous silica/sulfur composite cathodes exhibit excellent electrochemical performances including a high specific capacity of 1450 mA h g-1, a reversible capacity of 82.9 % after 100 cycles at a rate of C/2 (1 C = 1672 mA g-1) and an extended cyclability over 300 cycles at 1 C-rate. Furthermore, the high polysulfide adsorption property of porous silica has been proven by ex-situ analyses, showing a relationship between the surface area of silica and polysulfide adsorption ability. In particular, the modified porous silica/sulfur composite cathode, which is treated by a deep-lithiation process in the first discharge step, exhibits a highly reversible capacity of 94.5 % at 1C-rate after 300 cycles owing to a formation of lithiated-silica frames and stable solid-electrolyte-interphase layers
      PubDate: 2018-01-14T21:50:59.975915-05:
      DOI: 10.1002/asia.201701759
       
  • Solvent Impedes CO2 Cycloaddition on Metal-Organic Frameworks
    • Authors: Dan Shao; Jinbiao Shi, Jianling Zhang, Xiuniang Tan, Tian Luo, Xiuyan Cheng, Bingxing Zhang, Buxing Han
      Abstract: The catalytic performance of metal-organic frameworks (MOFs) for the synthesis of cyclic carbonate from carbon dioxide and epoxides has been explored in solvent and solvent-free conditions, respectively. It was found that MOF catalysts have significantly improved catalytic activities in solvent-free CO2 cycloaddition reactions than those in solvent. The mechanism was discussed from the competition of solvent with substrate to adhere MOF catalysts during reaction process.
      PubDate: 2018-01-13T11:25:21.252143-05:
      DOI: 10.1002/asia.201701706
       
  • In Situ Growth of MnO2 Nanosheets on N-Doped Carbon Nanotubes Derived from
           Polypyrrole Tubes for Supercapacitors
    • Authors: Xu Ou; Qi Li, Dan Xu, Jiangna Guo, Feng Yan
      Abstract: Nitrogen-doped porous carbon nanotubes@MnO2 (N-CNTs@MnO2) nanocomposites are prepared through the in situ growth of MnO2 nanosheets on N-CNTs derived from polypyrrole nanotubes (PNTs). Benefiting from the synergistic effects between N-CNTs (high conductivity and N doping level) and MnO2 nanosheets (high theoretical capacity), the as-prepared N-CNTs@MnO2-800 nanocomposites show a specific capacitance of 219 F g-1 at a current density of 1.0 A g-1, which is higher than that of pure MnO2 nanosheets (128 F g-1) and PNTs (42 F g-1) in 0.5 M Na2SO4 solution. Meanwhile, the capacitance retention of 86.8 % (after 1000 cycles at 10 A g-1) indicates an excellent electrochemical performance of N-CNTs@MnO2 prepared in this work.
      PubDate: 2018-01-13T00:26:44.309569-05:
      DOI: 10.1002/asia.201701752
       
  • Syntheses and properties of meso-substituted porphyrin mesogens with
           triazole linkages and peripheral alkyl chains
    • Authors: Ruilin Zhang; Hongfei Gao, Yanming Ren, Yulong Xiao, Jinliang Hu, Xiaohong Cheng
      Abstract: Novel discotic mesogens P/n-M (n = 12, 16, 18, M = 2H, Zn and Cu) bearing a porphyrin core, triazole linkages and peripheral 3,4,5-trialkoxybenzyl units have been synthesized by "click chemistry" approach. The thermal behavior, photophysical properties and morphologies of these compounds were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), UV and PL spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These compounds can self-assemble into hexagonal columnar phases in their pure states and form organogels in 1,4-dioxane with unusually flower-like sphere morphology. The supramolecular complexes of P/18-Zn with C70 or 4,7-di-4-pydriyl-2,1,3-benzothadiazole can display hexagonal columnar phases too. Additionally, zinc porphyrin compounds P/n-Zn show binding selectivity to Cu2+ among a series of cations in THF-H2O solution.
      PubDate: 2018-01-12T10:21:28.911748-05:
      DOI: 10.1002/asia.201701666
       
  • Copper-Catalyzed Oxidative Reaction of β-Keto Sulfones with Alcohols via
           C−S Bond Cleavage: Reaction Development and Mechanism Study
    • Authors: Bingnan Du; Wenmin Wang, Yang Wang, Zheng-Hang Qi, Jiaqi Tian, Jie Zhou, Xiaochen Wang, Jianlin Han, Jing Ma, Yi Pan
      Abstract: A Cu-catalyzed cascade oxidative radical process of β-keto sulfones with alcohols has been achieved by using oxygen as an oxidant. In this reaction, β-keto sulfones were converted into sulfinate esters under the oxidative conditions via cleavage of C-S bond. Experimental and computational studies demonstrate that a new pathway is involved in this reaction, which proceeds through the formation of the key four-coordinated Cu(II) intermediate, O−O bond homolysis induced C−S bond cleavage and Cu-catalyzed esterification to form the final products. This reaction provides a new strategy to sulfonate esters and enriches the research contend of the C−S bond cleavage and transformations.
      PubDate: 2018-01-12T10:20:24.481444-05:
      DOI: 10.1002/asia.201701694
       
  • Synthesis of hollow mesoporous TiO2 microspheres with single and double Au
           nanoparticles layers for enhanced visible light photocatalysis
    • Authors: Zia Ur Rahman; Ning Wei, Yange Feng, Xiaolong Zhang, Daoai Wang
      Abstract: A facile method was used to prepare hollow mesoporous TiO2 and Au@TiO2 spheres using polystyrene (PS) templates. Au nanoparticles (NPs) were simultaneously synthesized and attached on the surface of PS spheres by reducing AuCl4- ions using sodium citrate which resulted in the uniform deposition of Au NPs. The outer coating of titania via sol-gel produced PS@Au@TiO2 core-shell spheres. Removing the templates from these core-shell spheres through calcination produced hollow mesoporous and crystalline Au@TiO2 spheres with Au NPs inside the TiO2 shell in a single step. Anatase spheres with double Au NPs layers, one inside and another outside of TiO2 shell, were also prepared. Different characterization techniques indicated the hollow mesoporous and crystalline morphology of the prepared spheres with Au NPs. Hollow anatase spheres with Au NPs indicated enhanced harvesting of visible light and therefore demonstrated efficient catalytic activity toward the degradation of organic dyes under the irradiation of visible light as compared to bare TiO2 spheres.
      PubDate: 2018-01-12T08:30:41.096913-05:
      DOI: 10.1002/asia.201701786
       
  • Aerobic photooxidative synthesis of β-alkoxy mono-hydroperoxides using an
           organo photoredox catalyst controlled by a base
    • Authors: Yuya Asano; Yoshitomo Nagasawa, Eiji Yamaguchi, Akichika Itoh
      Abstract: In the proposed study, transition-metal-free synthesis of β-alkoxy monohydroperoxides via aerobic photooxidation using an acridinium photocatalyst was developed. This method enables the synthesis of some novel hydroperoxides. The peroxide source is molecular oxygen, which is cost-effective and is atomically efficient. Magnesium oxide plays an important role as a base in the catalytic system.
      PubDate: 2018-01-12T03:50:40.659556-05:
      DOI: 10.1002/asia.201701742
       
  • Constructing ordered three-dimensional channels of TiO2 for enhanced
           visible-light photo-catalytic performance of CO2 conversion induced by Au
           nanoparticles
    • Authors: Hairong Xue; Tao Wang, Hao Gong, Hu Guo, Xiaoli Fan, Bin Gao, Yaya Feng, Xianguang Meng, Xianli Huang, Jianping He
      Abstract: As a typical photo-catalyst for CO2 reduction, the practical application of TiO2 still suffers from low photo-catalytic efficiency and limited visible light absorption. Here, a novel Au-nanoparticle (NP)-decorated ordered mesoporous TiO2 (OMT) composite (OMT-Au) was successfully fabricated, in which Au NPs uniformly disperse on the OMT. Due to the surface plasmon resonance (SPR) effect derived from the excited Au NPs, TiO2 possesses high photo-catalytic performance for CO2 reduction under visible light. The ordered mesoporous exhibits the superiority of material and structure. This ordered mesoporous structure of TiO2 with a high surface area offers more catalytic activity sites. More importantly, the three-dimensional transport channels ensures smooth flow of gas molecules, high-efficient adsorption ability of CO2, and the fast and steady transmission of hot electrons excitation on Au NPs, thus leading to further improving photo-catalytic performance. These results highlight the possibility of improving visible light photo-catalysis for CO2 reduction by constructing OMT-based Au-SPR-induced photo-catalysts.
      PubDate: 2018-01-11T09:21:11.264686-05:
      DOI: 10.1002/asia.201701807
       
  • Imine-based architectures at surfaces and interfaces: from self-assembly
           to dynamic covalent chemistry in 2D
    • Authors: Iwona Janica; Violetta Patroniak, Paolo Samorì, Artur Ciesielski
      Abstract: During the last two decades dynamic covalent chemistry (DCC) has emerged as an efficient and versatile strategy for the design and synthesis of complex molecular systems in solution. While early examples of supramolecularly assisted covalent synthesis at surfaces relied strongly on kinetically controlled reactions for post-assembly covalent modification, the DCC method takes advantage of the reversible nature of bond formation and allows the generation of the new covalently bonded structures under thermodynamic control. These structurally complex architectures obtained via DCC protocols offer a wealth of solutions and opportunities towards the generation of new complex materials holding sophisticated properties. In this Focus Review we focus on the formation of covalently bonded imine-based discrete nanostructures, as well as one-dimensional (1D) and two-dimensional (2D) covalent organic frameworks (COFs) physisorbed on solid substrates under various experimental conditions, e.g. under ultra-high vacuum (UHV) or at the solid/liquid interface. Scanning tunneling microscopy (STM) is used to gain insight, with a sub-nanometer resolution, into the structure and properties of those complex nanopatterns.
      PubDate: 2018-01-11T09:20:36.456564-05:
      DOI: 10.1002/asia.201701629
       
  • Alkylation-, Heating-, and Doping-Induced Emission Enhancement of a
           Polyaromatic Tube in the Solid State
    • Authors: Kiyonori Kuroda; Masafumi Otsuki, Kohei Yazaki, Yoshihisa Sei, Munetaka Akita, Michito Yoshizawa
      Abstract: A polyaromatic tube with a subnanometer-sized cavity was efficiently prepared on a gram-scale through the stereo-controlled cyclotrimerization of a diphenylanthracene derivative as a key step. The facile exterior alkylation of the polyaromatic framework leads to a moderately fluorescent tube (R = -OC10H21; ΦF = 20%) in the solid state. The emission intensity of the solid-state alkyl-substituted tube is remarkably enhanced upon heating (up to 1.6 times, ΦF = 31%) as well as doping with fluorescent dyes (up to 4.2 times, ΦF = 83%) through efficient energy transfer.
      PubDate: 2018-01-11T05:31:36.211324-05:
      DOI: 10.1002/asia.201800034
       
  • Cobalt-Doped Perovskite-type Oxide LaMnO3 as Bifunctional Oxygen Catalysts
           for Hybrid Lithium-Oxygen Batteries
    • Authors: Xiao Liu; Hao Gong, Tao Wang, Hu Guo, Li Song, Wei Xia, Bin Gao, Zhongyi Jiang, Linfei Feng, Jianping He
      Abstract: Perovskite-type oxides based on alkaline-earth containing lanthanum manganate are the promising catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. The perovskite-type LaMnO3 shows excellent ORR performance but poor OER activity. In order to improve OER performance of LaMnO3, the element Co is doped into the perovskite-type LaMnO3 via a sol-gel method with following calcination process. To assess electrocatalytic activities for ORR and OER, a series of prepared LaMn1-xCoxO3 (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5) perovskite oxides were synthesized. The results indicate that the amount of doped Co has a significant effect on the catalytic performance of LaMn1-xCoxO3. As researched, when x = 0.3, LaMn0.7Co0.3O3 not only shows a tolerable electrocatalytic activity for ORR, but also exhibits a great improvement (> 200 mV) on the catalytic activity for OER, indicating the doping of Co is an effective approach to improve the OER performance of LaMnO3. Furthermore, the results demonstrate that the LaMn0.7Co0.3O3 is a promising bifunctional catalyst with cost-effective, applied and high-performance for ORR and OER in the hybrid Li-O2 batteries.
      PubDate: 2018-01-10T07:56:26.102662-05:
      DOI: 10.1002/asia.201701561
       
  • Synthesis of Metallic Nanoparticles Using Closed-Shell Structures as
           Templates
    • Authors: Li Qiu; Ryan McCaffrey, Wei Zhang
      Abstract: The synthesis and study of metallic nanoparticles are of continued and significant interest, with applications in materials science, catalysis, and medicine. The properties of metallic nanoparticles depend strongly on their particle size, shape, and interparticle distances. It is therefore desirable for the synthesis of metallic nanoparticles to be controlled for specific shapes and sizes. The rapid development in this research area has attracted intense interest from researchers with diverse expertise, and numerous methods towards the synthesis of monodisperse nanoparticles have been reported. In this Focus Review, we provide an overview of recent progress in the development of the template synthesis of metallic nanoparticles using closed-shell structures, including biological molecules/assemblies and cage molecules.Shell game: The properties of metallic nanoparticles depend strongly on their particle size, shape, and interparticle distances. It is therefore desirable to be able to control the synthesis towards specific shapes and sizes of metallic nanoparticles. This Focus Review provides an overview of recent progress in the development of the template synthesis of metallic nanoparticles using closed-shell structures, including biological molecules/assemblies and cage molecules (see figure).
      PubDate: 2018-01-10T07:26:17.359449-05:
      DOI: 10.1002/asia.201701478
       
  • Highly Luminescent and Water-Soluble Two-Dimensional Supramolecular
           Organic Framework: All Organic Photosensitizer Template for Visible Light
           Driven Hydrogen Evolution from Water
    • Authors: Hyun-Jun Lee; Hyeong-Ju Kim, Eung-Chang Lee, Jaekwan Kim, Soo Young Park
      Abstract: A highly fluorescent (ΦF = 0.60) and water-soluble two-dimensional (2D) honeycomb-shaped supramolecular organic framework (SOF) was successfully synthesized in pure aqueous solution via self-assembly of novel cyanostilbene-functionalized trilateral guest molecules and cucurbit[8]uril hosts. Size of this fluorescent 2D SOF was over 500 nm in diameter, 1.7 nm in thickness, and 3.9 nm in the honeycomb pore diameter. This 2D SOF showed a promising potential as a new all-organic photosensitizer template for photocatalytic H₂ evolution from pure water.
      PubDate: 2018-01-10T02:55:39.077009-05:
      DOI: 10.1002/asia.201800020
       
  • Transformations in Chemically Responsive Copper-Calixarene Architectures
    • Authors: Edmundo Percástegui; Carlos Reyes-Mata, Marcos Flores-Alamo, Beatriz Quiroz-García, Ernesto Rivera, Ivan Castillo
      Abstract: Self-assembly of bis-picolyl-appended calix[4]arene (L) with Cu(I) or Cu(II) salts resulted in a collection of multinuclear architectures capable of expressing structural reconfigurations in response to various chemical stimuli: addition of copper salt, solvents, or oxidation. Coordination of L to CuX (X = Br, I) selectively yielded dinuclear macrocycles Cu(I)₂L₂Br₂ (1) and Cu(I)₂L₂I₂ (3) that were transformed into tetranuclear assemblies Cu(I)₄L₂Br₄ (2) and Cu(I)₄L₂I₄ (4) upon further addition of CuX. These supramolecules persist as robust and discrete entities in solution that display red emission; notably, 4 exhibits luminescence thermochromism. Assembly of L with CuCl₂ produced macrocycle Cu(II)₂L₂Cl₄ (5), which crystallised as cage [Cu(II)₂L₄(μ-Cl)]³+ (6) in the presence of MeOH. Two chemical signals -introduction of CuCl₂ and addition of CH₃CN- regenerated macrocycle 5. Coordination of L with Cu(OTf) yielded macrocycle Cu(I)₂L₂(OTf)₂ (7) that also crystallised as cage 6 upon oxidation in CHCl₃.
      PubDate: 2018-01-09T09:50:24.684208-05:
      DOI: 10.1002/asia.201701741
       
  • Formation of fluorinated amido esters through unexpected C3-C4 bond
           fission in 4-trifluoromethyl-3-oxo-β-lactams
    • Authors: Hang Dao Thi; Hannelore Goossens, Dietmar Hertsen, Valerie Otte, Tuyen Van Nguyen, Veronique Van Speybroeck, Matthias D'hooghe
      Abstract: 4-Trifluoromethyl-3-oxo-β-lactams were unexpectedly transformed into 2-[(2,2-difluorovinyl)amino]-2-oxoacetates as major products, accompanied by minor amounts of 2-oxo-2-[(2,2,2-trifluoroethyl)amino]acetates, upon treatment with alkyl halides and triethylamine in DMSO. This peculiar C3-C4 bond fission reactivity was investigated in-depth, from both an experimental and a computational point of view, in order to shed light on the underlying reaction mechanism.
      PubDate: 2018-01-09T09:20:46.551704-05:
      DOI: 10.1002/asia.201701636
       
  • In situ generated ruthenium catalytic systems bearing diverse
           N-heterocyclic carbene precursors for the atom-economic amide synthesis
           from alcohols and amines
    • Authors: Hua Cheng; Mao-Qian Xiong, Chuan-Xiang Cheng, Hua-Jing Wang, Qiang Lu, Hong-Fu Liu, Fu-Bin Yao, Francis Verpoort, Cheng Chen
      Abstract: The transition-metal-catalyzed direct amide synthesis from alcohols and amines has been demonstrated as a highly environmental-benign and atom-economic process. Among various catalytic systems, in situ generated N-heterocyclic carbene (NHC)-based ruthenium (Ru) halide catalytic systems have been testified to be active for this attractive transformation. However, these existing catalytic systems usually required an additional ligand to achieve satisfactory results. In this work, through extensive screening from a diverse variety of NHC precursors, we discovered an active in situ catalytic system for the efficient amide synthesis without any additional ligand. Notably, this catalytic system is insensitive to the electronic effects of the substrates, and various electron-deficient substrates, which were not highly reactive with our previous catalytic systems, could be employed to efficiently afford the corresponding amides. Furthermore, mechanistic investigations were performed to demonstrate the rational for the high activity of the optimized catalytic system. The NMR scale reactions indicated that the rapid formation of a Ru hydride intermediate (a peak at -7.8 ppm from 1H NMR) after the addition of the alcohol substrate should be a pivotal factor for manifesting the high catalytic activity. Besides, HR-MS analysis demonstrated the possible structures of the in situ generated catalytic system.
      PubDate: 2018-01-09T09:20:33.190107-05:
      DOI: 10.1002/asia.201701734
       
  • Carbon Dots: Bottom-Up Syntheses, Properties, and Light-Harvesting
           Applications
    • Authors: Yuri Choi; Yeongkyu Choi, Oh-Hoon Kwon, Byeong-Su Kim
      Abstract: The development of cost-effective and environmentally friendly photocatalysts and photosensitizers has received tremendous attention because of their potential utilization in solar harvesting applications. In this respect, carbon dots (CDs) prepared by bottom-up methods have been considered to be promising light-harvesting materials. Through preparation from various molecular precursors and synthetic methods, CDs exhibit excellent optical and charge transfer properties. Furthermore, their photophysical properties can be readily optimized and enhanced by doping, functionalization, and post-synthetic treatment. In this review, we summarize the recent progress regarding CDs synthesized using bottom-up approaches that exhibit strong light absorption and unique electron donor/acceptor capabilities for light-harvesting applications. We anticipate that this review will provide new insights into novel types of photosensitizers and photocatalysts for a wide range of applications.
      PubDate: 2018-01-08T01:50:35.302531-05:
      DOI: 10.1002/asia.201701736
       
  • Hydrogen-doping into MoO3 supports toward modulated metal-support
           interactions and efficient furfural hydrogenation on iridium nanocatalysts
           
    • Authors: Lifang Xie; Ting Chen, Hang Cheong Chan, Yijin Shu, Qingsheng Gao
      Abstract: As promising supports, reducible metal oxides afford strong metal-support interactions to achieve efficient catalysis, relying on their band states and surface stoichiometry. Herein, in-situ and controlled hydrogen doping (H-doping) via H2 spillover is employed to engineer the metal-support interactions in hydrogenated MoOx supported Ir (Ir/H-MoOx) catalysts, and thus promote furfural hydrogenation to furfuryl alcohol. Via facilely varying reduction temperature, the resulting H-doping in a controlled manner tailors low-valence Mo species (Mo5+ and Mo4+) on H-MoOx supports, and thus charge-redistribution on Ir and H-MoOx interfaces. This further leads to obvious difference in H2 chemisorption on Ir, showing the promise for catalytic hydrogenation. As expected, the optimal Ir/H-MoOx with controlled H-doping affords high activity (TOF: 4.62 min-1) and selectivity (> 99%) in furfural hydrogenation at a mild condition (T = 30 oC, PH2 = 2 MPa), performing among the best of current catalysts.
      PubDate: 2018-01-05T05:55:35.281174-05:
      DOI: 10.1002/asia.201701661
       
  • Large-scalable Preparation of Photochromic Composite Foils with Excellent
           Reversibility for Light Printing
    • Authors: Yijie Zhou; Aibin Huang, Shidong Ji, Huaijuan Zhou, Ping Jin, Rong Li
      Abstract: Photochromic inks for repeatable light printing media have attracted increasing attention owing to the fact that it may be widely applied to reduce the consumption of papers and plastics for environmental conservation. Therefore, it is of practical significance to develop convenient photochromic inks at a low cost in a large scale. In this study, a simple one-step hydrothermal way was employed to prepare tungsten trioxide (WO3) nanoparticles which was further used to make photochromic inks and transparent photochromic films. The obtained transparent photochromic film could rapidly respond to UV light within tens of seconds, return to its initial state corresponding to different recovering time at each temperature and meanwhile exhibit good reversible coloration-bleaching effect. A typical PET foil coated with the photochromic ink can also be repeatedly light-printed for various patterns and display fabulous rewritable performance for tens of times. To sum up, this study proposes a simple method for the widespread applications of WO3-based photochromic inks.
      PubDate: 2018-01-05T03:25:20.553292-05:
      DOI: 10.1002/asia.201701747
       
  • Hierarchical nanoboxes composed of Co9S8-MoS2 nanosheets as efficient
           electrocatalysts for hydrogen evolution reaction
    • Authors: Vinoth Ganesan; Sunghyun Lim, Jinkwon Kim
      Abstract: Development of hydrogen evolution catalysts based on non-precious metals is essential for the practical application of water-splitting devices. Here, we report the synthesis of Co9S8-MoS2 hierarchical nanoboxes (HNBs) as efficient catalysts for hydrogen evolution reaction (HER). The surface of the hollow cubic structure was organized by CoMoS4 nanosheets formed by the reaction of MoS42- and Co2+ released from the Co-zeolite imidazole framework (ZIF-67) templates under reflux condition in a water-ethanol mixed solvent. The formation process of CoMoS4 HNB structures was characterized by TEM images obtained at various reaction temperatures. The amorphous CoMoS4 hierarchical nanoboxes were converted by sequential heat treatments to CoSx-MoS2 and Co9S8-MoS2 HNBs. Owing to their unique chemical compositions and structural features, Co9S8-MoS2 HNBs have high specific surface area (124.6 m2 g-1) and superior electrocatalytic performances for HER. The Co9S8-MoS2 HNBs exhibit a low overpotential (η10) of 106 mV, a low Tafel slope of 51.8 mV dec-1 and long-time stability in an acidic medium. The electrocatalytic activity of Co9S8-MoS2 HNBs is superior to the recently reported values and proves to be a promising candidate for HER.
      PubDate: 2018-01-01T06:15:26.462354-05:
      DOI: 10.1002/asia.201701536
       
  • Recent Progress of Upconversion in Nanostructured Materials: From Optical
           Tuning to Biomedical Applications
    • Authors: Feng Wang; Tianying Sun, Fujin Ai, Guangyu Zhu
      Abstract: Photon upconversion that is characterized by high-energy photon emission followed by lower-energy excitation was conventionally studied in bulk materials for several decades. The unique nonlinear luminescence process has become a subject of great attention since 2000 when upconverted emission was demonstrated in nanostructured crystals. In comparison with their bulk counterparts, nanostructured materials provide more rooms for optical fine-tuning by allowing flexible compositional integration and structural engineering. Moreover, the high colloidal stability of nanoparticles coupled with high amenability to surface functionalization opens up a number of new applications for upconversion, especially in the fields of biology and life science. In this focus review, we discuss recent development of upconversion materials through nanostructural design and review emerging biomedical applications involving these nanostructured upconversion materials. We also attempt to highlight challenging problems of these nanomaterials that constrain further progress in utilizing upconversion processes.
      PubDate: 2017-12-29T04:25:22.115896-05:
      DOI: 10.1002/asia.201701660
       
  • Silver-Catalyzed Efficient Synthesis of Oxindoles and Pyrroloindolines
           Using α-Aminoalkylation as the Key Step
    • Authors: Kyalo Stephen Kanyiva; Sohei Makino, Takanori Shibata
      Abstract: α-Aminoalkylation of N-arylacrylamides with amino acid derivatives was achieved by silver-catalysis in moderate to high yields. The reaction provides a new and efficient strategy for the synthesis of functionalized oxindoles, and is suitable for a wide range of both N-arylacrylamides and amino acids, which are inexpensive and readily available. The obtained oxindoles were readily transformed into densely functionalized pyrroloindolines by deprotection and cyclization in one pot.
      PubDate: 2017-12-28T09:57:20.034064-05:
      DOI: 10.1002/asia.201701739
       
  • Dibenzothieno-pyrrolo[3,2-b]pyrrole - the Missing Member of Thienoacenes
           Family
    • Authors: Daniel T Gryko; Małgorzata Czichy, Mariusz Tasior, Mieczysław Łapkowski
      Abstract: Dibenzothieno-pyrrolo[3,2-b]pyrrole and the corresponding bis(S,S-dioxide) were synthesised using concise synthetic strategy. Despite the presence of six fused aromatic rings, π-expanded pyrrolo[3,2-b]pyrroles of this type absorb and emit at relatively short wavelengths, which reflects inefficient π-conjugation due to the angular arrangement of aromatic rings. They exhibit interesting and complex electrochemical behavior, highlighting their potential in organic electronics. Both heteroacenes undergo two-stage oxidation, while remaining the independence of each 1-phenyl-1H-[1]benzothieno[3,2-b]pyrrole, which was proved by in situ ESR measurements. Interestingly, electrochemically generated dicationdiradicals are not only distributed over the pyrrolo[3,2-b]pyrrole scaffold, but also over the phenyl substituents located on nitrogen atoms.
      PubDate: 2017-12-22T10:10:27.222767-05:
      DOI: 10.1002/asia.201701639
       
  • Iron-Catalyzed Aminative Cyclization/Intermolecular Homolytic Aromatic
           Substitution Using Oxime Esters and Simple Arenes
    • Authors: Takuya Shimbayashi; Kazuhiro Okamoto, Kouichi Ohe
      Abstract: Intermolecular C-H alkylation of simple arenes in the presence of an iron catalyst has been achieved in a cascade manner with an aminative cyclization triggered by N-O bond cleavage of an alkene-tethered oxime ester. Various arenes, including electron-rich and electron-poor arenes, and heteroarenes can be employed in the reaction system. Regioselectivity and radical trapping experiments support the involvement of alkyl radical species, which undergo a homolytic aromatic substitution (HAS) to afford the arylation products.
      PubDate: 2017-12-13T21:42:15.412883-05:
      DOI: 10.1002/asia.201701634
       
 
 
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