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  Subjects -> CHEMISTRY (Total: 841 journals)
    - ANALYTICAL CHEMISTRY (50 journals)
    - CHEMISTRY (593 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (25 journals)
    - INORGANIC CHEMISTRY (41 journals)
    - ORGANIC CHEMISTRY (44 journals)
    - PHYSICAL CHEMISTRY (67 journals)

CHEMISTRY (593 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
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: 34)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 233)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
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 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: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 55)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 15)
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: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
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)
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: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 14)
American Mineralogist     Hybrid Journal   (Followers: 14)
Analyst     Full-text available via subscription   (Followers: 40)
Angewandte Chemie     Hybrid Journal   (Followers: 218)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 212)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 2)
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: 8)
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: 15)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
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: 293)
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: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 119)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 96)
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: 3)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 66)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
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: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 13)
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: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 174)
Chemical Science     Open Access   (Followers: 22)
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: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 26)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 142)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
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: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 256)
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: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
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)
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: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
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: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 12)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 58)
Dalton Transactions     Full-text available via subscription   (Followers: 22)
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: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 8)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)
Environmental Science : Nano     Partially Free   (Followers: 1)
Environmental Toxicology & Chemistry     Hybrid Journal   (Followers: 17)

        1 2 3 | Last

Journal Cover Chemistry - An Asian Journal
  [SJR: 1.833]   [H-I: 75]   [15 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  [1577 journals]
  • Cobalt-catalyzed Cross-dehydrogenative C(sp2)-C(sp3) Coupling of
           Oxazole/Thiazole with Ether or Cycloalkane
    • Authors: Xiaojiao Wang; Bowen Lei, Lifang Ma, Lisi Zhu, Xinyue Zhang, Hao Zuo, Dailin Zhuang, Ziyuan Li
      Abstract: Direct C5-alkylation of oxazole/thiazole with ether or cycloalkane has been achieved through a cobalt-catalyzed cross-dehydrogenative couling (CDC) process in moderate to good yields. This transformation represents the first C(sp2)-C(sp3) cross-coupling at the C5-position of azole via double C-H bond cleavages. Various functional groups on oxazole/thiazole substrates, as well as water and air, are well-tolerated with this concise and practical protocol, constituting straightforward access to heterocycles with great medicinal significance. A preliminary mechanism involving radical process has also been proposed.
      PubDate: 2017-09-19T22:40:27.962056-05:
      DOI: 10.1002/asia.201701258
       
  • Complexation Between (O-Methyl)6-2,6-Helic[6]arene and Tertiary Ammonium
           Salts: Acid/Base- or Chloride-Ion-Responsive Host–Guest Systems and
           Synthesis of [2]Rotaxane
    • Authors: Qiang Shi; Ying Han, Chuan-Feng Chen
      Abstract: The Front Cover shows a helic[n]arene cartoon character trying to pull a protonated ammonium species toward it, while other ionic species attempt to pull it away from the helic[n]arene. In their Full Paper, Chuang-Feng Chen et al. describe an artificial molecular host (O-methyl)6-2,6-helic[6]arene, showing excellent complexing ability to the protonated tertiary ammonium salts that were rarely used as guests before in host–guest chemistry. Interestingly, the formation and deformation of this kind of complex could be controlled by acid–base and chloride ions reversibly. Meanwhile, a helicarene-based [2]rotaxane was synthesized in a moderate yield. This mechanical structure could provide more opportunities to construct molecular machines and new smart materials. More information can be found in the Full Paper by Chuang-Feng Chen et al.
      PubDate: 2017-09-19T07:20:38.480721-05:
      DOI: 10.1002/asia.201701063
       
  • Catalytic Conversion of Dinitrogen into Ammonia under Ambient Reaction
           Conditions by Using Proton Source from Water
    • Authors: Yoshiaki Tanabe; Kazuya Arashiba, Kazunari Nakajima, Yoshiaki Nishibayashi
      Abstract: The Cover Feature shows Sanshiro Pond, located in the middle of the Hongo Campus of The University of Tokyo, which is covered with algae in the summer, where nitrogen is fixed by diazotrophic cyanobacteria. In their Communication, Yoshiaki Nishibayashi et al. describe how the molybdenum-catalyzed conversion of N2 into NH3 under ambient reaction conditions is achieved by using a proton source generated in situ from the ruthenium-catalyzed oxidation of H2O in combination with visible light and a photosensitizer. More information can be found in the Communication by Yoshiaki Nishibayashi et al.
      PubDate: 2017-09-19T07:20:27.875079-05:
      DOI: 10.1002/asia.201701195
       
  • Alkali Metal Cation Affinities of Anionic Main Group-Element Hydrides
           Across the Periodic Table
    • Authors: Zakaria Boughlala; Célia Fonseca Guerra, F. Matthias Bickelhaupt
      Abstract: The Cover Feature displays possible alkali cation/anionic base pairs across the periodic table. In their Full Paper, F. Matthias Bickelhaupt et al. discuss the results of an extensive exploration and detailed analyses of alkali metal cation affinities (AMCA) of archetypal anionic bases with electrophilic centers across the periodic table. AMCAs are significantly weaker and show a number of different trends if compared to the corresponding proton affinities (PAs). Bonding analyses trace the differences to the more diffuse nature and higher energy of the alkali cation ns LUMO as compared to the proton 1s LUMO. More information can be found in the Full Paper by F. Matthias Bickelhaupt et al.
      PubDate: 2017-09-19T07:20:21.989828-05:
      DOI: 10.1002/asia.201701234
       
  • Stimulus-Induced Conformational Transformation of Cyclic Peptide for
           Selective Cell Targeting On-Off Gatekeeper of Mesoporous Nanocarrier
    • Authors: Jeonghun Lee; Eun-Taex Oh, Jaehun Song, Ha Gyeong Kim, Heon Joo Park, Chulhee Kim
      Abstract: The αvβ3 integrin is upregulated on many cancer cells. We designed a dual functional cyclic peptide gatekeeper with a capability of stimuli-responsive conformational transformation which could serve as a selective cell targeting on-off gatekeeper for mesoporous nanocarriers. The advantage of employing the motif of stimuli-induced conformational transformation of cyclic peptides is that they could be utilized not only as an on-off gatekeeper for the triggered release of cargo drugs but also as a targeting ligand of the carriers to desired cells with their respective binding receptors. The peptide gatekeepers on the surface of nanocarriers exhibited on-off gatekeeping via conformational transformation triggered by intracellular glutathione levels of the cancer cells. The cyclic RGD sequence of the peptide gatekeepers enhanced the intracellular uptake into the tumor cells (A549) and the therapeutic efficacy of the nanocarrier.
      PubDate: 2017-09-17T21:31:20.08478-05:0
      DOI: 10.1002/asia.201701050
       
  • Silver Thiolate Nano-sized Molecular Clusters and Their Supramolecular
           Covalent Frameworks: An Approach Toward Pre-templated Synthesis
    • Authors: Zi-Yi Chen; Dennis Y. S. Tam, Leon Li-Min Zhang, Thomas Chung Wai Mak
      Abstract: A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2C2 using a C22- pre-templated approach. Herein, two prototype clusters Ag14(SR)6 and CO3@Agm(SR)10 (R = isopropyl, cyclohexyl or tert-butyl; m = 18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely Ag14(S-iPr)6(CF3CO2)8·DMSO6 (two polymorphic forms 1, 2) and [Ag14(S-Cy)6(CO2CF3)8(DMSO)4] · DMSO3 (3), and a cluster-based metal-organic framework {Ag3[Ag14(S-iPr)6(CF3CO2)11(H2O)3CH3OH] · (H2O)2.5}n (4) have been isolated and structurally characterized. Furthermore, increased acidity of the reaction mixture afforded three carboxylate-templated cluster based frameworks : a chain-like compound {[HN(CH3)2CO][CO3@Ag18(S-tBu)10(NO3)7DMF4]·DMF}n (5), as well as two layer-type compounds, namely {Ag[CO3@Ag20(S-iPr)10(CO2CF3)9(CF3CO2H)(CH3OH)2]}n (6) and {Ag2[CO3@Ag20(S-Cy)10(CO2CF3)10(CF3CO2H)2(H2O)2]·(H2O)3·(CH3OH)3}n (7) exhibiting sql-net characteristics. It is demonstrated that the C≡C2- pre-template, which draws several Ag+ ions together to form the C2@Agn entity, plays an indispensable role in the syntheses of these compounds. Furthermore, covalent linkage of these nano-sized silver thiolate clusters from one- to three-dimensions revealed enormous potential for the future development of silver cluster-based frameworks.
      PubDate: 2017-09-15T04:20:23.912928-05:
      DOI: 10.1002/asia.201701150
       
  • NIR Absorbing Donor-Acceptor Based 1,1,2,2-Tetracyanobutadiene (TCBD) and
           Cyclohexa-2,5-Diene-1,4-Ylidene-Expanded TCBD Substituted
           Ferrocenyl-Phenothiazines
    • Authors: Rajneesh Misra; Madhurima Poddar
      Abstract: A series of unsymmetrical (D-A-D1, D1-π-D-A-D1 and D1-A1-D-A2-D1) and symmetrical (D1-A-D-A-D1 ) type of phenothiazines 4b, 4c and 5b-5f were designed and synthesized by [2 + 2] cycloaddition-retroelectrocyclization reaction of ferrocenyl substituted phenothiazines with tetracyanoethylene (TCNE) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). The photophysical, electrochemical and computational studies show strong charge-transfer (CT) interaction in the phenothiazine derivatives which can be tuned by the variation of number of TCNE/TCNQ acceptors. The phenothiazines 4b, 4c and 5b-5f show red shifted absorption in 400-900 nm region, resulting in lower band gap which is supported by TD-DFT calculations. The electrochemical study exhibits reduction waves at low potential due to strong 1,1,2,2-tetracyanobutadiene (TCBD) and cyclohexa-2,5-diene-1,4-ylidene-expanded TCBD acceptors. The incorporation of cyclohexa-2,5-diene-1,4-ylidene-expanded TCBD stabilizes LUMO energy level to greater extent as compared to TCBD.
      PubDate: 2017-09-13T03:27:29.299455-05:
      DOI: 10.1002/asia.201700879
       
  • Cancer-targeted Selenium Nanoparticles Sensitize Cancer Cells to
           Continuous γ Radiation to Achieve Synergetic Chemo-Radiotherapy
    • Authors: Leung Chan; Lizhen He, Binwei Zhou, Shouhai Guan, Mingjun Bo, Yahui Yang, Ying Liu, Xiao Liu, Yanyang Zhang, Qiang Xie, Tianfeng Chen
      Abstract: Cancer radiotherapy with 125I seeds demonstrates long-term higher efficacy and lower side effects than traditional X-ray radiotherapy due to its low-dose and continuous radiation but is still limited by radioresistance in clinical applications. Therefore, the design and synthesis for sensitizers that could enhance the sensitivity of cancer cells to 125I seeds is of great importance for future radiotherapy. Selenium nanoparticles (SeNPs) have been found to exhibit high potential in cancer chemotherapy and as drug carriers. In this study, we found that, based on the Auger-electron effect and Compton effect of Se atoms, cancer-targeted SeNPs in combination with 125I seeds achieve synergetic effects to inhibit cancer cell growth and colony formation through induction of cell apoptosis and cell cycle arrest. Detailed studies on the action mechanisms reveal that the combined treatments effectively activate intracellular ROS overproduction to regulate p53-mediated DNA damage apoptotic signalling pathways and MAPKs phosphorylation and to prevent the self-repair of cancer cells simultaneously. Taken together, the combination of SeNPs with 125I seeds could be further exploited as a safe and effective strategy for next-generation cancer chemo-radiotherapy in clinical applications.
      PubDate: 2017-09-11T10:41:11.165485-05:
      DOI: 10.1002/asia.201701227
       
  • Room-temperature Synthesis of Amorphous Molybdenum Oxide Nanodots with
           Tunable Localized Surface Plasmon Resonances
    • Authors: Chuanhui Zhu; Qun Xu, Liang Ji, Yumei Ren, Mingming Fang
      Abstract: Two dimensional (2D) semiconductors have recently emerged as a remarkable class of plasmonic alternative to conventional noble metals. However, tuning of their plasmonic resonances towards different wavelengths in the visible light region with physical or chemical method still remains challenging. In this work, we design a simple room-temperature chemical reaction route to synthesize the amorphous molybdenum oxide (MoO3-x) nanodots that exhibit strong localized surface plasmon resonances (LSPR) in the visible and near infrared region. Moreover, tunable plasmon resonances can be achieved in a wide range with the changing solvent surrounding, and accordingly the photoelectrocatalytic activity can be optimized with the varying LSPR peaks. So this work boosts the light matter interaction at the nanoscale and could enable photodetectors, sensors, and photovoltaic devices in the future.
      PubDate: 2017-09-08T07:41:53.735471-05:
      DOI: 10.1002/asia.201701170
       
  • Water Splitting via Decoupled Photocatalytic Water Oxidation and
           Electrochemical Proton Reduction Mediated by Electron-Coupled-Proton
           Buffer
    • Authors: Fei Li; Fengshou Yu, Jian Du, Yong Wang, Yong Zhu, Xiaona Li, Licheng Sun
      Abstract: Water splitting mediated by electron-coupled-proton buffer (ECPB) provides an efficient way to avoid gas mixing by separating oxygen evolution from hydrogen evolution in space and time. Though electrochemical and photoelectrochemcial water oxidation have been incorporated in such two-step water splitting system, alternative ways to reduce the cost and energy input for decoupling two half-reactions are desired. Herein, we show the feasibility of photocatalytic oxygen evolution in a powder system with BiVO4 as a photocatalyst and polyoxometalate H3PMo12O40 as an electron and proton acceptor. The resulting reaction mixture was allowed to be directly used for the subsequent hydrogen evolution with the reduced H3PMo12O40 as electron and proton donors. Our system exhibits excellent stability in repeated oxygen and hydrogen evolution, which brings considerable convenience to decoupled water splitting.
      PubDate: 2017-09-08T07:41:02.002743-05:
      DOI: 10.1002/asia.201701123
       
  • In Situ Fabricating Inorganic/Organic Hybrid Based on Cu/Co-ZIF and Cu2O
    • Authors: Tianlong Wang; Hong Ma, Jin Gao, Xinhong Wang, Yuxia Sun, Yang Luo, Shujing Zhang, Jie Xu
      Abstract: We successfully fabricate well-defined inorganic/organic hybrid Cu2O@Cu/Co-ZIF (ZIF = zeolitic imidazolate frameworks) by use of growth of dual-metal Cu/Co-ZIF on the performed Cu2O hollows. The key point of the strategy is coupling the in situ self-sacrifice of Cu2O and the coordination of metal ions (Cu+ and Co2+) with 2-methylimidazole. This new hybird was characterized by powder X-ray diffraction, (scanning) transmission electron microscopy, energy dispersive spectrometer mapping, in situ FT-IR spectroscopy, UV-Vis diffuse reflection spectroscopy, N2 sorption measurements, and electron spin resonance. It was evidenced that Cu/Co-ZIF nanocrystals have been assembled to contineous shells surround the Cu2O cores as well as in the voids between layers and inner pores. Cu2O@Cu/Co-ZIF exhibits visible light responsibility and potentially as narrow band gap semiconductor and visible photocatalyst.
      PubDate: 2017-09-08T01:20:32.339598-05:
      DOI: 10.1002/asia.201701189
       
  • Improved Electrochemical Cycling Durability in a Nickel Oxide double layer
           film
    • Authors: Shuai Hou; Xiang Zhang, Yanlong Tian, Jiupeng Zhao, Hongbin Geng, Huiying Qu, Hangchuan Zhang, Kun Zhang, Binsheng Wang, A. I. Gavrilyuk, Yao Li
      Abstract: For the first time, a crystalline-amorphous double-layered NiOx film has been prepared by reactive radio frequency magnetron sputtering, which has exhibited improved electrochemical cycling durability, whereas other electrochromic parameters have been maintained at the required level, i.e. the short coloration/bleaching time (0.8s/1.1s) and an enhanced transmittance modulation range (62.2%) at the wavelength of 550 nm. Besides this, the double-layered film has shown the best reversibility as compared with amorphous and crystalline single-layer films.
      PubDate: 2017-09-07T03:20:43.824102-05:
      DOI: 10.1002/asia.201700994
       
  • Current Advances in Quantum Dots-Based Photoelectrochemical Immunoassays
    • Authors: Dianping Tang; Jian Shu
      Abstract: As a newly developing technique, the PEC immunoassay has drawn a great attention in recent years because of its low cost and desirable sensitivity. Since the detecting signal originates from photoelectric conversion of photoelectric materials, the appearance and application of QDs that process unique photophysical properties and regulated optoelectronic characteristics, take the development of PEC immunoassay to a new height. This review concisely introduces the general mechanism of QDs-based photoelectric conversion for immunoassay and summarizes the current advances of QDs applications in immunoassay. Considering the signal strategies and photoactive materials are the key elements in the PEC biosensor system, we highlight the state-of-the-art signaling strategies and various applications of QDs in PEC immunoassay to comprehensive introduce the advance of QDs-based PEC immunoassay. Finally, the challenge and future developmental trend are briefly discussed.
      PubDate: 2017-09-07T02:20:25.781815-05:
      DOI: 10.1002/asia.201701229
       
  • A Pyridoindole-Based Multifunctional Bioprobe: pH-Induced Fluorescence
           Switching and Specific Targeting of Lipid Droplets
    • Authors: Bahadur Sk; Pilendra Kumar Thakre, Raghuvir Singh Tomar, Abhijit Patra
      Abstract: What a PITE! A multifunctional fluorescent bioprobe based on pyridoindole (PI) and tetraphenylethylene (TE), PITE, showing pH-responsive fluorescence switching in solution, as nanoparticles and in the solid state that can be used to sense toxic organic acid vapor is presented. Hydrophobic nanoparticles of PITE turned out to be highly specific for the imaging of lipid droplets (LDs) in diverse organisms. Selective targeting of LDs by PITE in lower eukaryotes, such as yeast, and in mammalian cells both in vivo and in vitro show the potential of PITE for real-time tracking of LDs under pathophysiological conditions. More information can be found in the Full Paper by Raghuvir Singh Tomar, Abhijit Patra et al. (
      DOI :10.1002/asia.201700898).
      PubDate: 2017-09-04T07:55:29.863625-05:
       
  • Robust Acenaphthoimidazolylidene Palladacycles: Highly Efficient Catalysts
           for the Amination of N-Heteroaryl Chlorides
    • Authors: Qinyue Deng; Yang Zhang, Haibo Zhu, Tao Tu
      Abstract: The perfect match: Challenging and selective amination of N-heteroaryl chlorides by diverse primary and secondary amines has been successfully realized by using robust and congested N-heterocyclic carbene palladacycles as catalysts. Furthermore, the coupling protocol is readily extended to synthesize rosiglitazone, a clinical drug for diabetes mellitus, highlighting its potential pharmaceutical feasibility. More information can be found in the Communication by Tao Tu et al. (
      DOI :10.1002/asia.201700877).
      PubDate: 2017-09-04T07:45:29.317626-05:
       
  • A Multiple-Stimulus Responsive Biomimetic Assembly Based on
           Polyisocyanopeptide and Conjugated Polymer
    • Authors: Fanfan Meng; Chengfen Xing, Hongbo Yuan, Yibing Fan, Ran Chai, Yong Zhan
      Abstract: An assembly has been fabricated and indicated as a multiple-stimulus responsive biomimetic hybrid polymer architecture. It was constructed by the hydrophobic interactions between the conjugated polyfluorene containing 2,1,3-benzothia-diazole units (PFBT) and the tri(ethylene glycol)-functionalized polyisocyanopeptide (3OEG-PIC). The introduction of PFBT to the polyisocyanopeptide (PIC) network allows for the incorporation of multiple-stimulus responsiveness including temperature, CO2, carbonic anhydrase and nonlinear mechanics, which mimics the natural processes and interactions. Furthermore, the light-harvesting and signal amplification characteristics of PFBT endow the supramolecular assembly with the essential function of fluorescence monitoring for the biological process.
      PubDate: 2017-09-04T05:19:01.841611-05:
      DOI: 10.1002/asia.201701280
       
  • Color Tuning in Garnet Oxides: The Role of Tetrahedral Coordination
           Geometry for 3d-Metal Ions and Ligand-Metal Charge Transfer (band gap
           manipulation)
    • Authors: Srinivasan Natarajan; Jagannatha Gopalakrishnan, Sourav Laha, Anupam Bhim
      Abstract: Abstract: We have explored garnet structured oxide materials containing 3d-transition metal ions (Co2+, Ni2+, Cu2+, Fe3+) for the development of new inorganic colored materials. For this purpose, we have synthesized new garnets, Ca3Sb2Ga2ZnO12 (I) and Ca3Sb2Fe2ZnO12 (II), that are isostructural with Ca3Te2Zn3O12. Substitution of Co2+, Ni2+, Cu2+ at the tetrahedral Zn2+ sites in (I) and (II) gives rise to brilliantly colored materials (different shades of blue, green, turquoise and red). The materials are characterized by optical absorption spectral study and CIE chromaticity diagrams. The Fe3+ containing oxides show a band gap narrowing (due to strong sp-d exchange interactions between Zn2+ and transition metal ion), which tunes the color of these materials uniquely. We have also characterized the color and optical absorption properties of Ca3Te2Zn3-xCoxO12 (0 < x ≤ 2.0) and Cd3Te2Zn3-xCoxO12 (0 < x ≤ 1.0) displaying brilliant blue and green-blue colors, respectively. The present work brings out the role of distorted tetrahedral coordination geometry of TM ions and ligand-metal charge transfer (manifesting as band gap narrowing) in producing brillianly colored garnet based materials.
      PubDate: 2017-09-04T03:26:14.910735-05:
      DOI: 10.1002/asia.201701040
       
  • Synthesis of Pinpoint-Fluorinated Polycyclic Aromatic Hydrocarbons:
           Benzene Ring Extension Cycle Involving Microwave-Assisted SNAr Reaction
    • Authors: Kohei Fuchibe; Hisanori Imaoka, Junji Ichikawa
      Abstract: Lords of the Rings: Owing to the electronic and steric impacts of fluorine substituents, pinpoint-fluorinated polycyclic aromatic hydrocarbons (PAHs) are promising organic semiconductors that might result in printable organic electronic devices. In this study, the development of an aromatic ring extension cycle that allows transformation of fluoroarenes into extended fluoroarenes by one benzene ring per cycle is reported. The synthesis of pinpoint-fluorinated picene, having five benzene rings was successfully demonstrated by performing multiple cycles starting from commercially available 1-fluoronaphthalene. More information can be found in the Communication by Kohei Fuchibe, Hisanori Imaoka, and Junji Ichikawa (
      DOI :10.1002/asia.201700870).
      PubDate: 2017-09-04T03:06:07.466039-05:
       
  • Controlled synthesis of 3D flower-like Ni2P composed by mesoporous
           nanoplates for overall water-splitting
    • Authors: Ge Wang; Haiyan Zheng, Xiubing Huang, Zhenyu Wu, Hongyi Gao, Wenjun Dong
      Abstract: Developing efficient non-noble metal and earth-abundant electrocatalysts with tunable microstructure for overall water-splitting is critical to promote the clean-energy technologies for hydrogen economy. Herein, novel three-dimensional (3D) flower-like Ni2P composed by mesoporous nanoplates with controllable morphology and high surface area was prepared by a hydrothermal method and low-temperature phosphidation as efficient electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Comparing with the scamps-like NixPy, the 3D flower-like Ni2P with a diameter of 5 μm presented efficient and stable catalytic performance in 0.5 M H2SO4, with a small Tefal slope of 79 mV dec-1 and an overpotential of ~ 240 mV at a current density of 10 mA cm-2 with a mass loading density of 0.283 mg cm-2. Besides, the catalyst also exhibited a remarkable performance for OER in 1.0 M KOH electrolyte, with the overpotential of 320 mV to reach current density of 10 mA cm-2 and a small Tafel slope of 72 mV dec-1. The excellent catalytic performance of as-prepared Ni2P may be ascribed to its novel 3D morphology with unique mesoporous structure
      PubDate: 2017-09-01T04:20:37.721382-05:
      DOI: 10.1002/asia.201701255
       
  • Recent developments in lanthanide single-molecule magnets
    • Authors: Jingjing Lu; Mei Guo, Jinkui Tang
      Abstract: Single-molecule magnets (SMMs) exhibiting slow relaxation of magnetization of purely molecular origin are highly attractive owing to their potential applications in spintronic devices, high-density information storage and quantum computing. Particularly, lanthanide SMMs have been playing a major role in the advancement of this field because of the large intrinsic magnetic anisotropy of lanthanide metal ions. In this Focus Review, some recent breakthroughs that are changing the perspective of the field will be highlighted with special emphasis on the synthetic strategies towards the design of high-performance SMMs.
      PubDate: 2017-09-01T04:20:32.506751-05:
      DOI: 10.1002/asia.201701032
       
  • Control synthesis of PbS-TiO₂ hollow hybrid structures through ion
           adsorption-heating progress and their photocatalytic activity
    • Authors: hongbo xia; Suli Wu, shufen zhang
      Abstract: Hollow hybrid nanostructure has received significant attention because of its unique structural features. This study reports a facile "ion adsorption-heating" method to fabricate PbS-TiO₂ hybrid hollow particles. In this method, the TiO₂ spheres used as substrate material to grow PbS are aggregates of many small amorphous TiO₂ particles, and each of the small particles is covered by thioglycollic acid ligands through Ti4+-carboxyl coordination. When the Pb2+ ions were added into the TiO₂ spheres colloidal solution, these ions can be adsorbed by sulfydryl (-SH) groups to form metal thiolate, and the C-S bond will be dissociated by heating to release S2-. Then, the S2- will react with Pb2+ ions to form PbS without additives as sulfur sources. Meanwhile, the amorphous TiO₂ spheres were transformed into anatase phase during the heating process. As a result, the crystallization of TiO₂ spheres along with the formation of PbS was simultaneously carried out by heating. During the heating process, owing to the Kirkendall effect of S2- diffusion and Ostwald ripening effect of the crystallization of amorphous TiO₂ spheres, PbS-TiO₂ hollow hybrid structure can be obtained. The XRD and XPS characterizations proved the formation of anatase TiO₂ and PbS. The characterization of TEM confirmed the formation of the hollow structure of PbS-TiO₂ hybrid sample. The photocatalytic activity of the PbS-TiO₂ hollow hybrid spheres have been investigated by the degradation of Cr6+ under visible light. The results show that PbS-TiO₂ hollow hybrid spheres exhibited highest photocatalytic activity, in which almost all the Cr6+ were degraded after 140 min.
      PubDate: 2017-08-31T03:21:03.793634-05:
      DOI: 10.1002/asia.201701204
       
  • Chlorination-promoted Transformation of Isolated Pentagon Rule C78 into
           Fused-pentagons- and Heptagons-containing Fullerenes
    • Authors: Victor A. Brotsman; Daria V. Ignat'eva, Sergey I. Troyanov
      Abstract: Cage transformations in fullerenes are rare phenomena which are still not fully understood. We report the first skeletal transformation of an Isolated-Pentagon-Rule (IPR) isomer of C78 fullerene upon high-temperature chlorination which proceeds by six-step Stone–Wales rearrangements affording non-IPR, non-classical (NC) C78(NC2)Cl24 with two cage heptagons, six pairs of fused pentagons, and an unprecedented loop-like chlorination pattern. The following loss of a C2 unit results in C76(NC3)Cl24 containing three cage heptagons.Nonclassical: High-temperature chlorination of Isolated Pentagon Rule C78 fullerene with SbCl5 results in the isolation of non-IPR, non-classical C2-C78Cl24 containing 2 heptagons and 14 pentagons in the lens-like carbon cage (see picture).The reconstruction of the reaction pathway revealed that the six-step cage transformation occurs circularly via Stone–Wales rearrangements. An additional step of a C2 loss leads to the formation of C76Cl24 with 3 cage heptagons.
      PubDate: 2017-08-29T11:21:28.808394-05:
      DOI: 10.1002/asia.201701011
       
  • Anilines as C-Nucleophiles in Ir-Catalyzed Intramolecular Asymmetric
           Allylic Substitution Reactions
    • Authors: Shuli You; Zheng-Le Zhao, Qing Gu, Xin-Yan Wu
      Abstract: Anilines generally act as N-nucleophiles in transition-metal catalyzed allylic substitution reactions. In this paper, a highly enantioselective intramolecular Friedel-Crafts type allylic alkylation of aniline derivatives was realized by using an iridium catalyst derived from [Ir(cod)Cl]2 and (Ra)-BHPphos. Various tetrahydroisoquinilin-5-amines were obtained in moderate to good yields, excellent enantioselectivity and regioselectivity under mild reaction conditions.
      PubDate: 2017-08-28T09:16:31.804461-05:
      DOI: 10.1002/asia.201701192
       
  • The forgotten nitro-aromatic phosphines as weakly donating P- ligands: a
           N-aryl-benzimidazolyl series in RhCl(CO) complexes
    • Authors: Chonhwei Zhu; Emmanuel Gras, Carine Duhayon, Francis Lacassin, Xiuling Cui, Remi Chauvin
      Abstract: The coordination chemistry of the a priori weakly -donating nitro-aromatic phosphines is addressed through a series of nitro-substituted (N-phenyl-benzimidazol-1-yl)diphenylphosphines in Rh(I) complexes. From a set of seven such phosphines L = Lxyz(') (x, y, z = 0 or 1 = number of NO2 substituent at the 5, 6 and N-Ph para positions, respectively), including the non-nitrated parent L000 and its dicationic N-methyl counterpart L000', three LRhCl(COD) and seven L2RhCl(CO) complexes have been obtained in 72-95 % yield. Despite of a cis orientation of the L and CO ligands, the C=O IR stretching frequency CO varies in the expected sense, from 1967 ± 1 cm-1 for Lxy0 to 1978 ± 1 cm-1 for Lxy1, and 2005 cm-1 for L000'. The 103Rh NMR chemical shift Rh varies from -288 ppm for L000 to -316 ± 1 ppm for L10z or L01z, and -436 ppm for L000'. The CO and Rh probes thus reveal moderate but systematic variations, and act as "orthogonal" spectroscopic indicators of the presence of nitro groups on the N-Ph group and the benzimidazole core, respectively. For the dicationic ligand L000', a tight electrostatic sandwiching of the Rh-Cl bond by the benzimidazole moities is evidenced by X-ray crystallography (RhCl-…CN2+ ≈ 3.01 Å). Along with the LRhCl(CO) complexes, dinuclear side-products (µ-CO)(RhClL)2 were also obtained in low spectroscopic yield: for the dinitro ligand L = L011, a unique 1:6.7 clathrate structure, with dichloromethane as solvate, is also revealed by X-ray crystallography.
      PubDate: 2017-08-28T05:26:45.692054-05:
      DOI: 10.1002/asia.201701078
       
  • Computer-assisted design of imidazolate-based ionic liquids for improving
           SO2 capture, CO2 capture, and SO2/CO2 selectivity
    • Authors: Guokai Cui; Ning Zhao, Jianji Wang, Congmin Wang
      Abstract: A new strategy using computer-assisted design of substituted imidazolate-based ionic liquids (ILs) through tuning the absorption enthalpy as well as the basicity of ILs for improving SO2 capture, CO2 capture, and SO2/CO2 selectivity was reported. The best substituted imidazolate-based ILs as absorbents for different applications were predicted at first. During the absorption, a high SO2 capacity up to 5.28 and 2.38 mole SO2 per mole IL could be achieved by ILs with CH3-imidazolate anion under 1.0 and 0.1 bar, respectively, through tuning multiple N∙∙∙S interactions between SO2 and N atoms in the imidazolate anion with different substituent. In addition, CO2 capture by imidazolate-based ILs could also be easily tuned through changing the substitute of ILs, and Br-imidazolate IL showed the high CO2 capacity but low absorption enthalpy. Furthermore, the high selectivity for SO2/CO2 could be reached by imidazolate-based ILs with CN-imidazolate anion due to their high SO2 capacity but low CO2 capacity. The results put forward in this work are in good agreement with the prediction. Quantum chemical calculations, FT-IR and NMR analysis methods were used to discuss SO2 and CO2 absorption mechanism.
      PubDate: 2017-08-24T22:35:33.336058-05:
      DOI: 10.1002/asia.201701215
       
  • Two Series of Homodinuclear Lanthanide Complexes: Greatly Enhancing the
           Energy Barriers through Tuning the Terminal Solvent Ligands in Dy2
           Single-Molecule Magnets
    • Authors: Yahong Li; Yaru Qin, haifeng Zhang, Hao Sun, Yangdan Pan, Yu Ge, Yiquan Zhang
      Abstract: The utilization of 2-ethoxy-6-(((2-hydroxy-3-methoxy benzyl)imino)methyl)phenol (H2L) as a chelating ligand, in combination with the employment of alcohols (EtOH and MeOH) as auxiliary ligands, in the 4f-metal chemistry afforded two series of dinuclear lanthanide complexes of compositions [Ln2L2(NO3)2 (EtOH)2] (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7)) and [Ln2L2(NO3)2(MeOH)2] (Ln = Sm (8), Eu (9), Gd (10), Tb (11), Dy (12), Ho (13), Er (14)). Complexes 1-7 are isomorphous. The two LnIII ions in 1-7 are doubly bridged by two deprotonated aminophenoxide oxygen atoms of two μ2: η0:η1:η2:η1:η1:η0 L2- ligands. One nitrogen atom, two oxygen atoms of NO3- anion, two methoxide oxygen atoms of two ligand sets, and one oxygen atom of the terminal-coordinated EtOH molecule complete the distorted dodecahedron geometry of each LnIII ion. Compounds 8-14 are isomophous and their structures are similar to those of 1-7. The slight difference between 1-7 and 8-14 stems from purposefully replacing the EtOH ligands in 1-7 with MeOH in 8-14. Dc magnetic susceptibility studies in the 2-300 K range reveal probably weak antiferromagnetic interactions for 3, 4, 7, 10, 11, and 14, and ferromagnetic interactions at low temperature for 5, 6, 12, and 13. Complexes 5 and 12 exhibit SMM behavior with energy barriers of 131.3 K for 5 and 198.8 K for 12, respectively. Namely, the energy barrier is significantly enhanced by dexterously regulating the terminal ligands. To rationalize the observed difference in the magnetic behavior, complete-active-space self-consistent field (CASSCF) calculations were performed on two Dy2 complexes. Subtle variation in the angle θ between the magnetic axes and the vector connecting two DyIII ions results in the weaker influence on the tunneling gap of individual DyIII ions by the dipolar field in 12. This work proposes an efficient strategy for synthesizing Dy2 SMMs with high energy barriers.
      PubDate: 2017-08-24T21:35:50.847251-05:
      DOI: 10.1002/asia.201701065
       
  • Nanocarbons for Catalytic Desulfurization
    • Authors: Qingqing Gu; Yangming Lin, Saskia Heumann, Dangsheng Su
      Abstract: Abstract: Nanocarbon catalysts are green and sustainable alternatives to the metal-based catalysts for numerous catalytic transformations. The application of nanocarbons for environmental catalysis is an emerging research discipline and has undergone rapid development in recent years. In this focus review, we provide a critical analysis on the state-of-the-art nanocarbon catalysts for three different catalytic desulfurization processes. And the focus is on the advantage and limitation as well as the reaction mechanism of the nanocarbon catalysts at molecular level.
      PubDate: 2017-08-24T12:35:21.397071-05:
      DOI: 10.1002/asia.201700995
       
  • Organozinc-Mediated Direct C-C Bond Formation via C-N Bond Cleavage of
           Ammonium Salt
    • Authors: Dong-Yu Wang; Koki Morimoto, Ze-Kun Yang, Chao Wang, Masanobu Uchiyama
      Abstract: We report a direct cross-coupling reaction between diarylzinc (Ar2Zn) and aryltrimethylammonium salts (ArNMe3+·-OTf) in the presence of LiCl, via C-N bond cleavage. The reaction takes place smoothly upon heating in THF without any external catalyst, enabling efficient and chemo/stereo-selective formation of biaryl products. Mechanistic study indicates that the reaction proceeds through a single electron transfer route.
      PubDate: 2017-08-22T08:00:36.432844-05:
      DOI: 10.1002/asia.201701132
       
  • Target-Selective Fluorescence Imaging and Photo-Cytotoxicity against
           H₂O₂ High-Expressing Cancer Cells Using a Photoactivatable Theranostic
           Agent
    • Authors: Ryoma Takagi; Ayano Takeda, Daisuke Takahashi, Kazunobu Toshima
      Abstract: A purpose-designed and synthesized H₂O₂-reactive and photoactivatable theranostic agent 1 consisting of 1) an arylboronic acid moiety, 2) pro-fluorophore moiety, and 3) photoactivatable moiety (photosensitizer), selectively and effectively reacted with H₂O₂ while simultaneously releasing resorufin for fluorescence detection under neutral aqueous conditions. In addition, 1 was cell permeable, and exhibited effective photo-cytotoxicity against fluorescently visualized cells only upon photo-irradiation. The results also showed that 1 produced a selective fluorescence response to H₂O₂, even in living cultured cells.
      PubDate: 2017-08-22T08:00:22.857313-05:
      DOI: 10.1002/asia.201701004
       
  • Steric twist effect-induced different ternary memory characteristics in
           non-conjugated copolymers with pendant naphthalene and 1,8-naphthalimide
           moieties
    • Authors: Ming Wang; Zhuang Li, Hua Li, Jinghui He, Najun Li, Qingfeng Xu, Jian-Mei Lu
      Abstract: In this paper, novel random copolymer PMNN and PMNB were designed and synthesized, and the memory devices Al/PMNN or PMNB/ITO both exhibit the ternary memory performance. The switching voltages of OFF-ON1 and ON1-ON2transitions for both memory devices are around -2.0 V and -3.5 V, respectively, and the ON1/OFF, ON2/ON1 current ratio are both up to 103. The observed tristable electrical conductivity switching could be attributed to field-induced conformational ordering of naphthalene ring in the side chain, and subsequent charge trapping of 1,8-naphthalimide moieties. More interestingly, through adjusting the connection sites of 1,8-naphthalimide moieties to tune the steric twist effect, different memory properties (PMNN with nonvolatile WORM memory behavior, while PMNB with volatile SRAM memory behavior) were achieved. This result will offer a guideline for the design of different high-performance multilevel memory devices via tuning steric effects of the chemical moieties.
      PubDate: 2017-08-22T02:00:32.60688-05:0
      DOI: 10.1002/asia.201701044
       
  • Fabrication of Mesoporous Cu Films on Cu Foils and Their Applications to
           Dopamine Sensing
    • Authors: Daisuke Baba; Cuiling Li, Victor Malgras, Bo Jiang, Hatem R. Alamri, Zeid A. Alothman, Md. Shahriar A. Hossain, Yusuke Yamauchi, Toru Asahi
      Abstract: We previously succeeded to prepare stable mesoporous Cu films on Au-coated conductive working electrodes by using polystyrene-b-poly(oxyethylene) (PS63 000-b-PEO26 000) micelles as template and sulfuric acid to increase ionic conductivity. In the present study, we report the preparation of mesoporous Cu films on Cu foil. By changing the Cu salts and electrodeposition potentials, we discuss how these parameters influence the final product. Without having to filtrate interefering species, such as uric acid, ascorbic acid and glucose, the dopamine concentration can be precisely determined by applying a suitable potential. Therefore, non-invasive electrochemical sensing based on mesoporous films will be useful for daily diagnosis of mental disorder.Dopamine sensing: The preparation of mesoporous Cu films on Cu foil is reported. By changing the Cu salts and electrodeposition potentials, we discuss how these parameters influence the final product. Without having to filtrate interfering species, such as uric acid and ascorbic acid, the dopamine concentration can be precisely determined by applying a suitable potential.
      PubDate: 2017-08-21T07:45:47.774493-05:
      DOI: 10.1002/asia.201700862
       
  • A Multiple Structure-Design Strategy towards Ultra-Thin Niobate Perovskite
           Nanosheets with Thickness-Dependent Photocatalytic Hydrogen Evolution
           Performance
    • Authors: Yannan Zhou; Ting Wen, Xiaofan Zhang, Binbin Chang, Weiqian Kong, Yanzhen Guo, Baocheng Yang, Yonggang Wang
      Abstract: Hydrogen production by catalytic water splitting using sunlight holds great promise for clean and sustainable energy source. Despite the efforts made in the past decades, challenges still exist in pursuing solid catalysts with light harvesting capacity, large surface areas and efficient utilities of the photo-generated carrier at the same time. Here, we demonstrate a multiple structure design strategy to achieve highly enhanced photocatalytic performance on hydrogen production from water splitting in Dion-Jacobson perovskites KCa2Nan-3NbnO3n+1. Specifically, chemical doping (N/Nb4+) of the parent oxides via ammoniation improved the ability of sunlight harvesting efficiently; Subsequent liquid exfoliation of the doped perovskites yielded ultra-thin [Ca2Nan-3NbnO3n+1]- nanosheets with greatly increased surface areas. Significantly, the maximum hydrogen evolution appears in the n=4 nanosheets, which suggests the most favorable thickness for charge separation in such perovskite-type catalysts. The optimized black N/Nb4+-[Ca2NaNb4O13]- nanosheets show greatly enhanced photocatalytic performance, as high as 973 μmol/h with Pt-loading, on hydrogen evolution from water splitting. As a proof-of-concept demonstration, this work highlights the feasibility of combining various chemical strategies towards better catalysts and precise thickness-control of two-dimensional materials.
      PubDate: 2017-08-21T04:00:28.704963-05:
      DOI: 10.1002/asia.201701001
       
  • A Facile Access to Ortho-Hydroxyanilnes Based on Ir(III)-Catalyzed Direct
           C−H Amidation of 2-Phenoxypyridines
    • Authors: Lianhui Wang; Zi Yang, Mengqi Yang, Miaodou Tian, Changshen Kuai, Xiuling Cui
      Abstract: A highly efficient and regioselective C−H amidation of 2-phenoxypyridines catalyzed by Ir(III) has been developed using sulfonyl azides as readily amino source. The amidated products were provided in good to excellent yields with broad functional group tolerance. Furthermore, the 2-pyridyl moiety in the amidated products can readily be removed, offering an efficient route to ortho-hydroxyanilnes, which are important building block in organic synthesis.
      PubDate: 2017-08-21T03:12:09.736683-05:
      DOI: 10.1002/asia.201701028
       
  • Impact of Linear Alkyl Length on Assembly of Twisted Perylene Bisimides:
           from Molecular Arrangement to Nanostructures
    • Authors: Zongxia Guo; Kun Wang, Ping Yu, Xiangnan Wang, Shusha Lan, Kai Sun, Yuanping Yi, Zhibo Li
      Abstract: Length effect of linear alkyl chains substituted at imine positions on the assembly of tetrachlorinated perylene bisimides (1, PBI with -C6H13; 2, PBI with -C12H25) has been investigated. Solvent-induced assembly was performed in solutions mixed by THF and methanol via varying their volume ratios. Morphological (SEM, AFM and TEM) and spectral (UV-vis, FL, FTIR and XRD) methods were used to characterize the assembled nanostructures and the molecular arrangement in the aggregates. It was found that uniform structures could be obtained for both molecules in solutions with high ratio of methanol, although 1 preferred to form rigid nanosheets while 2 assembled into more long stripes with high ratio of length to width. Combined the nanostructures with the spectral data, it was suggested that the π-π stacking predominated in assemblies for 1, and synergetic effect of Van der Waals from the long alkyl chains and π-πstacking between neighbouring building blocks facilitated the growth of long range ordered nanostructures of 2. Then via changing the linear chain length, the hierarchical assembly of PBIs modified on bay positions could be manipulated effectively.
      PubDate: 2017-08-18T07:01:25.504338-05:
      DOI: 10.1002/asia.201700984
       
  • Modulatory Functionalization of Gold Nanorods using Supramolecular
           Assemblies
    • Authors: Sundo Jeong; Hongrual Park, Dongmin Seon, Jongwan Choi, Ki Bum Hong, Jiseok Lee, Chaekyu Kim, Jung-Keun Kim, Myoung-Hwan Park
      Abstract: Supramolecular assembly-mediated functionalization of gold nanorods (GNRs) has been developed by reversible phase transfer between water and oils, which offers a facile method for fabricating stubborn GNRs with surface charge tunability. In this regard, TMA-GNRs were initially prepared from conventional CTAB-GNRs via a ligand exchange reaction in the presence of excess of TMA ligands. To further expand their functionality and potential applications, electrostatic assemblies of positively charged TMA-GNRs with negatively charged oleate ions were prepared. These assemblies (OA-GNRs) can undergo facile phase transfer from water to hexane. Interestingly, the reversible electrostatic assembly between the TMA and oleate ions fabricated onto GNRs can be easily disrupted by treatment with HCl, which removes the oleate ions from GNRs to give reTMA-GNRs that can be made soluble in aqueous media again. In addition, OA-GNRs can be further used for the synthesis of negatively charged GNRs such as MUA-GNRs which are hard to prepare directly from CTAB-GNRs. This versatile method for phase transfer and functionalization on GNRs is expected to broaden the scope of their applications in sensing, biomedical imaging, photothermal therapies, and drug delivery systems.
      PubDate: 2017-08-17T03:20:38.365365-05:
      DOI: 10.1002/asia.201700932
       
  • Catalytic Conversion of Dinitrogen into Ammonia under Ambient Reaction
           Conditions by Using Proton Source from Water
    • Authors: Yoshiaki Tanabe; Kazuya Arashiba, Kazunari Nakajima, Yoshiaki Nishibayashi
      Abstract: Molybdenum-catalyzed conversion of molecular dinitrogen into ammonia under ambient reaction conditions has been achieved by using a proton source generated in situ from the ruthenium-catalyzed oxidation of water in combination with visible light and a photosensitizer. The preset reaction system is considered as a new model for the nitrogen fixation by photosynthetic bacteria.
      PubDate: 2017-08-17T02:21:51.257018-05:
      DOI: 10.1002/asia.201701067
       
  • Tailoring Hierarchical Zeolites with Designed Cationic Surfactants and Its
           High Catalytic Performance
    • Authors: Kai Zhang; CHAO LI, Zewei Liu, Min Wang, Xin Yan, Hongxia Xi
      Abstract: Three hierarchical porous zeolites (H-*BEA, H-MTW and H-*MRE) were successfully synthesized with the assistant of designed cationic surfactants under hydrothermal synthesis conditions. The as-synthesized zeolite samples can be easily regulated by changing the number of long hydrophobic n-alkyl chains. Also, we investigated the relationship between the length of the surfactant and the formation of microporous structure of zeolite. Furthermore, alkylation of benzene with propene was performed as probe reaction to evaluate the catalytic performance of the synthesized hierarchical zeolites. The resulting materials were characterized by a complementary combination techniques of X-ray powder diffraction, N2 adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, 28Si and 27Al MAS NMR spectroscopes, thermogravimetric analysis, and computer simulation. These analyses results indicated that quaternary ammonium surfactants acted as organic structure-directing agents (OSDAs) in the formation of such hierarchical zeolite samples, whether the surfactant has long hydrophobic tail groups or not. The simulation results indicated that the organic molecules with no long hydrophobic chain can lead to the synthesis of zeolite by the charge control, and the hydrophobic molecules with long hydrophobic chains can be carried out through the orbital control. These hierarchical zeolites showed improved catalytic activities towards the industrially-relevant alkylation of benzene with propene comparing with the conventional zeolites of the same frameworks. More importantly, the success of using quaternary ammonium surfactants with no hydrophobic n-alkyl tail group to the synthesis of hierarchically structured mesoporous zeolites, provides a new pathway to the synthesis of hierarchical porous materials via soft-templating method.
      PubDate: 2017-08-17T01:20:23.688507-05:
      DOI: 10.1002/asia.201700942
       
  • Metallofullerenol inhibits cellular iron uptake by inducing transferrin
           tetramerization
    • Authors: Jinxia Li; Xueqing Xing, Baoyun Sun, Yuliang Zhao, Zhonghua Wu
      Abstract: Herein, A549 tumor cell proliferation was confirmed to be positively dependent on the concentration of Fe3+ or transferrin (Tf). Gd@C₈₂(OH)₂₂ or C₆₀(OH)₂₂ effectively inhibited the iron uptake and the subsequent proliferation of A549 cells. The conformation changes of Tf mixed with FeCl₃, GdCl₃, C₆₀(OH)₂₂ or Gd@C₈₂(OH)₂₂ were obtained by SAXS. The results demonstrate that Tf homodimers can be decomposed into monomers in the presence of FeCl₃, GdCl3 or C₆₀(OH)₂₂, but aggregated into tetramers in the presence of Gd@C₈₂(OH)₂₂. The larger change of SAXS shapes between Tf+C₆₀(OH)₂₂ and Tf+FeCl₃ implies that C₆₀(OH)₂₂ is bound to Tf, jamming the iron binding site. The larger deviation of SAXS shape from a possible crystal structure of Tf tetramer implies that Gd@C₈₂(OH)₂₂ is bound to Tf tetramer, disturbing iron transport. This study well explains the inhibition mechanism of Gd@C₈₂(OH)₂₂ and C₆₀(OH)₂₂ on iron uptake and the proliferation of A549 tumor cells and highlights the specific interactions of nanomedicine with the target biomolecules in cancer therapy.
      PubDate: 2017-08-16T23:20:41.745652-05:
      DOI: 10.1002/asia.201700910
       
  • Iron-cobalt phosphomolybdate with high electrocatalystic activity for
           oxygen evolution reaction
    • Authors: Haoying Zhai; Taotao Gao, Ting Qi, Yajie Zhang, Guangfeng Zeng, Dan Xiao
      Abstract: Iron-cobalt phosphomolybdate (FeCoPM12) nanoparticles,a high-efficient catalytic material for oxygen evolution reaction (OER), were fabricated via a coprecipitation route. Compared with iron-cobalt hydroxide and state-of-art RuO2 electrocatalysts, the as-prepared FeCoPM12 sample exhibited robust OER catalytic activity with a low overpotential of 258 mV at a current density of 10 mA cm-2 and a small Tafel slope of 33 mV dec-1. Moreover, the as-synthesized sample presented preferable stability, and after 10 h at 1.52 V, the current density merely degrades 8.3 percent. It's ascribed to the high electrochemical stability and small porous structure of FeCoPM12 material, which provide effective electron transmission and improve the catalytic performance for OER in alkaline medium.
      PubDate: 2017-08-16T13:20:24.51948-05:0
      DOI: 10.1002/asia.201700905
       
  • High order in a self-assembled Iridium (III) complex gelator towards
           nanostructured IrO2 thin films
    • Authors: Francesca Scarpelli; Andreea Ionescu, Iolinda Aiello, Massimo La Deda, Alessandra Crispini, Mauro Ghedini, Elvira Brunelli, Settimio Sesti, Nicolas Godbert
      Abstract: The preparation and characterization of a new metallogelator based on the Ir(III) discrete cyclometallated complex [(ppy)2Ir(bpy)](CH3CH2OCH2CO2) are reported, where H(ppy) is 2-phenylpiridine and bpy is 2,2'-bipyridine, used as ancillary ligand. The compound is able to self-assemble in water in a range of concentrations between 3% and 6 % w/w, creating a luminescent ordered supramolecular gel. The gel and xerogel architectures were investigated through POM, SEM and TEM microscopies coupled with Powder X-Ray Diffraction. The gel supramolecular organization is characterized by columnar tetragonal strands, already present at high dilution conditions, of cations surrounded by counteranions. These strands, in turn, are self-assembled in an oblique columnar cell upon gelification. The xerogel thin films obtained upon complete dehydration maintained the gel supramolecular order and can be used as precursor for the preparation of nanostructured IrO2 thin films.
      PubDate: 2017-08-16T08:20:40.858404-05:
      DOI: 10.1002/asia.201700930
       
  • Graphene Oxide as a Carbocatalyst for Diels-Alder Reaction in Aqueous
           Media
    • Authors: Yarabhally R Girish; Subrata Pandit, Subhendu Pandit, Mrinmoy De
      Abstract: The [4+2] Cycloaddition reaction, known as Diels-Alder reaction, has a great importance in synthetic organic chemistry and frequently used in synthesis of natural products containing six-membered ring. Herein, we have reported an efficient protocol for Diels-Alder reaction between 9-hydroxymethylanthracene and N-substituted maleimides using two dimensional graphene oxide (GO) as a heterogeneous carbocatalyst in an aqueous medium at room temperature. High yield, wide substrate scope, low temperature, exceptional functional group tolerance, atom-economical, and water as a green solvent are the noteworthy features of this protocol. The heterogeneous GO catalyst is easily recoverable and has been used for multiple times without any appreciable loss in the catalytic activity.
      PubDate: 2017-08-16T02:21:24.692904-05:
      DOI: 10.1002/asia.201701072
       
  • Live cell imaging using photoswitchable diarylethene doped fluorescent
           polymer dots
    • Authors: Yasuko Osakada; Tuyoshi Fukaminato, Yuma Ichinose, Mamoru Fujitsuka, Yoshie Harada, Tetsuro Majima
      Abstract: Fluorescence photoswitching using nanomaterials has recently emerged as a promising approach for the imaging of biological targets. However, despite intensive research efforts during the last decade, practical microscopy of biological targets using photoswitchable nanoparticles in real time remains challenging. To address this problem, we have developed live macrophage cell imaging and single particle imaging methods, using photoswitchable fluorescent diarylethene-doped polymer nanoparticles (P-dots) under Xe lamp irradiation. We established a 34-times prolonged 'off-state', using P-dots doped with a diarylethene containing methoxy substituent, upon visible light irradiation using a Xe lamp and a green fluorescent protein filter cube. To demonstrate the practicality of doped P-dots imaging, we imaged lysosome in a macrophage cell, and observed 11-times slower recovery of the fluorescence from 'off-state' to 'on-state', indicating their potential for cellular imaging.
      PubDate: 2017-08-15T21:21:08.592281-05:
      DOI: 10.1002/asia.201701038
       
  • Dynamic Self-Assembly of Gold/Polymer Nanocomposites: pH-Encoded Switching
           between 1D Nanowires and 3D Nanosponges
    • Authors: Da-Hui Qu; Qi Zhang, Tian-Yi Xu, Cai-Xin Zhao, Wei-Hang Jin, Qian Wang
      Abstract: The design of tunable dynamic self-assembly of nanoparticles with switchable assembled dimensions and morphologies is a challenging goal whose realization is vital for the evolution of smart nanomaterials. Herein we show the chitosan polymer as an effective supramolecular "glue" for aldehyde-modified Au nanoparticles to reversibly modulate the states of self-assembled nanocomposites. By simultaneous integration of dynamic covalent Schiff base interactions and noncovalent hydrogen bonds, the chitosan/Au nanocomposites could reversibly transform their assembled morphologies from one-dimensional nanowires to three-dimensional nanosponges in response to the variation of pH value. Moreover, the obtained nanosponges could be used as an efficient pH-controlled cargo release system.
      PubDate: 2017-08-15T09:15:32.175386-05:
      DOI: 10.1002/asia.201701119
       
  • β−Functionalized Push-Pull Opp-Dibenzoporphyrins as Sensitizers for
           Dye-Sensitized Solar Cells
    • Authors: hong Wang; Yi Hu, Shivaraj Yellappa, Michael B. Thomas, R. G. Waruna Jinadasa, Alex Matus, Max Shulman, Francis D'souza
      Abstract: A novel class of β-functionalized push-pull zinc opp-dibenzoporphyrins were designed, synthesized and utilized as sensitizers for dye-sensitized solar cells. Spectral, electrochemical and computational studies were systematically performed to evaluate their spectral coverage, redox behavior and electronic structures. These porphyrins displayed much broader spectral coverage and more facile oxidation upon extension of π−conjugation. Free-energy calculations and femtosecond transient absorption studies (charge injection rate in the range of 1011 s-1) suggest efficient charge injection from the excited singlet state of porphyrin to the conduction band of the TiO2. The PCE of YH3 bearing acrylic acid linkers (η = 5.9%) is close to that of the best ruthenium dye N719 (η = 7.4%) under similar conditions. The superior photovoltaic performance of YH3 is attributed to its higher light harvesting ability and its more favorable electron injection and collection as supported by electrochemical impedance spectral studies. This work demonstrates the exceptional potentials of benzoporphyrins as sensitizers for dye-sensitized solar cells.
      PubDate: 2017-08-11T08:26:46.297536-05:
      DOI: 10.1002/asia.201701117
       
  • Interface Engineered Ni(OH)2/β-like FeOOH electrocatalysts for Highly
           Efficient and Stable Oxygen Evolution Reaction
    • Authors: Kaijian Zhu; Wenjun Luo, Guoxiang Zhu, Jun Wang, Yongfa Zhu, Zhigang Zou, Wei Huang
      Abstract: Fe-based (oxy)hydroxides are especially attractive electrocatalysts for oxygen evolution reaction (OER) due to their earth-abundance, low cost and non-toxicity. However, poor OER kinetics on the surface restricts the performance of FeOOH electrocatalyst. In this work, we obtain a highly efficient and stable Ni(OH)2/β-like FeOOH electrocatalyst by facile electro-activation treatment. The activated Ni(OH)2/β-like FeOOH sample indicates an overpotential of 300 mV @ 10 mA cm-2 for OER and no obvious current decay after 50 h test, which can be comparable to the most efficient Ni-based and Co-based electrocatalysts on the planar substrates. Further studies suggest that β-like FeOOH plays a key role in the remarkably enhanced performance during electro-activation process due to its metastable tunnel structure with lower barrier for interface duiffusion of Ni2+ ions between the bilayer electrocatalyst. This study develops a new strategy to explore efficient and low-cost electrocatalysts and deepens understanding of bilayer electrocatalysts for OER.
      PubDate: 2017-08-09T22:20:32.995731-05:
      DOI: 10.1002/asia.201700964
       
  • Self-assembly of a 3-Symmetric π-Conjugated Molecules family on Surface
           Studied by STM: Two-Dimensional Multi Nanoporous Frameworks
    • Authors: Qingdao Zeng; Hongliang Dai, Shuai Wang, Ichiro Hisaki, Shoichi Nakagawa, Nobuaki Ikenaka, Ke Deng, Xunwen Xiao
      Abstract: In this contribution, we have investigated the on-surface self-assembled behaviors of four C3-symmetric π-conjugated planar molecules (Tp, T12, T18, and Ex). These molecules have been proven to be excellent building blocks for constructing non-covalent organic frameworks in bulk phase. Their hydrogen-bonded two-dimensional (2D) on-surface self-assemblies are observed under STM investigation at solid/liquid interface, which are of much difference with those in bulk crystal. Upon the combination of STM technique and density functional theory (DFT) calculation, we reveal the formation mechanism of different assemblies, especially, the critical role of the hydrogen bonding in the assemblies. This research provides us not only a deep insight into the self-assembled behaviors of these novel functional molecules, but also a convenient approach toward construction of 2D multi porous networks.
      PubDate: 2017-08-08T03:15:22.06644-05:0
      DOI: 10.1002/asia.201700749
       
  • Macrocycles All Aflutter: Substitution at an Allylic Center Reveals
           Conformational Dynamics of [13]-Macrodilactones
    • Authors: Kelli M Rutledge; Trevor Hamlin, Donna Baldisseri, Matthias Bickelhaupt, Mark Wayne Peczuh
      Abstract: The shapes adopted by large-ring, macrocyclic compounds play a role in their reactivity and their ability to be bound by biomolecules. We investigate the synthesis, conformational analysis, and properties of a specific family [13]-macrodilactones as models of natural product macrocycles. The features of our macrodilactones enable us to study the relationship between stereogenic centers and planar chirality through the modular synthesis of new members of this family of macrocycles. Here we report on insights gained from a new [13]-macrodilactone that is substituted at a position adjacent to the alkene in the molecule. Analysis of the compound, in comparison to an α-substituted regioisomer, by X-ray crystallography, NMR coupling constants, and reaction product characterization in concert with computational chemistry revealed that the alkene unit is dynamic. That is, the data support a model wherein the alkene in our [13]-macrodilactones is oscillating between two conformations. A difference in reactivity of one conformation compared to the other leads to manifestation of this dynamic behavior. The results underscore the local conformational dynamics observed in some natural product macrocycles, which could have implications for biomolecule binding.
      PubDate: 2017-08-07T13:15:42.101791-05:
      DOI: 10.1002/asia.201700997
       
  • Alkynylation of bio-based HMF to connect biomass processing with
           conjugated polymers and furanic pharmaceuticals
    • Authors: Leonid Romashov; Valentine P. Ananikov
      Abstract: Acetylene-functionalized platform chemicals were synthesized for the first time based on biomass-derived 5-hydrohymethylfurfural (HMF). Demanded mono- and bis-ethynylfurans were obtained in high yields (89-99%). Plausible application of these products in the synthesis of smart organic conjugated materials and pharmaceuticals was addressed in a series of transformations. Conjugated polyacetylenic polymers with morphology control have been prepared with the incorporation of the HMF core.
      PubDate: 2017-08-07T11:15:24.056849-05:
      DOI: 10.1002/asia.201700940
       
  • Photophysics, electrochemistry, morphology and bioimaging applications of
           new 1,8-naphthalimide derivatives containing different chromophores
    • Authors: Ankita Saini; K R Justin Thomas, Abhay Sachdev, Packrisamy Gopinath
      Abstract: A series of 1,8-naphthalimide-based fluorophores containing different chromophores with varying conjugation and electron richness at imidic nitrogen are synthesized and characterized. These amine-functionalized naphthalimides are bipolar in nature and exhibit interesting optical and morphological variations attributable to the nature of N-substituents. Despite the dyes are structurally different due to the substituent variation in the imidic nitrogen, their electronic characteristics are similar originating from the 4-aminonaphthalimide segment. Nevertheless, they exhibited variations in morphology at the microscopic domain attributable to the structural differences. Further, these fluorescent dyes display biocompatibility and demonstrated in bioimaging of cells.
      PubDate: 2017-08-07T09:15:26.926964-05:
      DOI: 10.1002/asia.201700968
       
  • Stereogenic-Only-at-Metal Asymmetric Catalysts
    • Authors: Lilu Zhang; Eric Meggers
      Abstract: Chirality is an essential feature of asymmetric catalysts. This review summarizes asymmetric catalysts that derive their chirality exclusively from stereogenic metal centers. Reported chiral-at-metal catalysts can be divided into two classes, namely, inert metal complexes, in which the metal fulfills a purely structural role, so catalysis is mediated entirely through the ligand sphere, and reactive metal complexes. The latter are particularly appealing because structural simplicity (only achiral ligands) is combined with the prospect of particularly effective asymmetric induction (direct contact of the substrate with the chiral metal center). Challenges and solutions for the design of such reactive stereogenic-only-at-metal asymmetric catalysts are discussed.Defined by the core: This review summarizes asymmetric catalysts that derive their chirality exclusively from stereogenic metal centers. The chiral-at-metal catalysts can be divided into two classes, namely, inert metal complexes, in which the metal fulfills a purely structural role, so catalysis is mediated entirely through the ligand sphere, and reactive metal complexes (see scheme).
      PubDate: 2017-08-07T06:31:42.779224-05:
      DOI: 10.1002/asia.201700739
       
  • Alkali Metal Cation Affinities of Anionic Maingroup-Element Hydrides
           Across the Periodic Table
    • Authors: Zakaria Boughlala; Celia Fonseca Guerra, F. Matthias Bickelhaupt
      Abstract: We have carried out an extensive exploration of gas-phase Alkali Metal Cation Affinities (AMCA) of archetypal anionic bases across the periodic system using relativistic density functional theory at ZORA-BP86/QZ4P//ZORA-BP86/TZ2P. AMCA values of all bases were computed for the lithium, sodium, potassium, rubidium and cesium cations and compared with the corresponding proton affinities (PA). One purpose of this work is to provide an intrinsically consistent set of values of the 298 K AMCAs of all anionic (XHn-1-) constituted by maingroup-element hydrides of groups 14-17 along the periods 2-6. In particular, we wish to establish the trend in affinity for a cation as the latter varies from proton to, and along, the alkali cations. Our main purpose is to understand these trends in terms of the underlying bonding mechanism using Kohn-Sham molecular orbital theory together with a quantitative bond energy decomposition analyses (EDA).
      PubDate: 2017-08-05T11:00:35.352517-05:
      DOI: 10.1002/asia.201700956
       
  • Intelligent, Biodegradable, and Self-Healing Hydrogels Utilizing DNA
           Quadruplexes
    • Authors: Shizuma Tanaka; Kenta Wakabayashi, Kazuki Fukushima, Shinsuke Yukami, Ryuki Maezawa, Yuhei Takeda, Kohei Tatsumi, Yuichi Ohya, Akinori Kuzuya
      Abstract: A new class of hydrogels utilizing DNA (DNA quadruplex gel) has been constructed by directly and symmetrically coupling deoxynucleotide phosphoramidite monomers to the ends of polyethylene glycols (PEGs) in liquid phase, and using the resulting DNA-PEG-DNA triblock copolymers as macromonomers. Elongation of merely four deoxyguanosine residues on PEG, which produces typically ~10 grams of desired DNA-PEG conjugates in one synthesis, realized intelligent and biodegradable hydrogels utilizing DNA quadruplex formation, responsive to various input signals such as Na+, K+, and complementary DNA strand. Gelation of DNA quadruplex gels takes place within a few seconds upon the addition of a trigger, enabling free formation just like Ca+-alginate hydrogels or possible application as an injectable polymer (IP) gel. Resulting hydrogels show quite high thermal stability and rheological properties, and even show self-healing abilities.
      PubDate: 2017-08-04T09:02:34.612698-05:
      DOI: 10.1002/asia.201701066
       
  • Precise Labelling and Tracking Lipid Droplet in Adipocytes Using a
           Luminescent ZnSalen Complex
    • Authors: Juan Tang; Yanfei Zhang, Hao-Yan Yin, Guoheng Xu, Jun-Long Zhang
      Abstract: Designing two-photon probes for precise labelling lipid droplet (LD) and monitoring LD dynamics in adipocytes is of great significance to understand LD homeostasis. We herein report that a luminescent metal complex LD-TPZn can specifically image LDs in adipose cells and tissue using one- or two-photon fluorescence microscopy. Importantly, LD-TPZn exhibited higher specificity to LD than commercial Nile Red and Bodipy 493/503, probably due to different cellular uptake pathways, clathrin-mediated endocytosis and non-selectively passive diffusion, respectively. More importantly, LD-TPZn can be applied as a two-photon LD probe to image adipose tissue, one of the most challengeable tissues for traditional one-photon fluorescence microscope imaging due to the strong light scattering. Most importantly, LD-TPZn can be used to monitor LD growth during adipogenesis of preadipocytes, which is highly desirable to unravel the relationship between LD homeostasis and metabolic diseases.
      PubDate: 2017-08-04T07:01:11.911121-05:
      DOI: 10.1002/asia.201701010
       
  • How a Transition Metal(II) Chloride Interacts with a Eutectic
           AlCl₃-based Ionic Liquid: Insights into the speciation of the
           Electrolyte and electrodeposition of Magnetic Materials
    • Authors: Giridhar Pulletikurthi; Bernd Weidenfeller, Andriy Borodin, Jan C Namyslo, Frank Endres
      Abstract: Abstract: Electrostatic interactions are characteristic for ionic liquids, they play a pivotal role in determining the formation of species when solutes are dissolved in them. The formation of new species/complexes has been investigated for certain ILs. However, such investigations have not yet been focused on eutectic liquids, which get emerging interest as a promising class of ILs. These liquids (or Liquid Coordination Complexes, LCCs) are rather new and are composed of cationic and anionic chloro complexes of metals. To date, these liquids have been employed as electrolytes to deposit metals and as solvents for catalysis. The present study deals with a liquid that is prepared by mixing 1.2:1 mol ratio of AlCl₃ and 1-butylpyrrolidine. An attempt has been done to understand the interactions of FeCl₂ with the organic molecule using spectroscopy. It was found that dissolved Fe(II) species interact mainly with the IL anion and such interactions can lead to the changes in the cation of the electrolyte. Furthermore, the viability of depositing thick magnetic films of Fe and Fe-Al has been explored.
      PubDate: 2017-08-04T07:00:35.034098-05:
      DOI: 10.1002/asia.201700520
       
  • Influence of Surface Morphology and Conductivity on Photocatalytic
           Performance of Solution-Processed Zinc Oxide Film
    • Authors: JeongSoo Hong; Nobuhiro Matsushita, Takashi Shirai, kazuya Nakata, Chiaki Terashima, Akira Fujishima, Ken-ichi Katsumata
      Abstract: In this study, we fabricated the solution-processed ZnO films having various structures, and investigated the influence of surface morphology and conductivity on photocatalytic performance including improvement of conductivity, hydrogen production, and photo-degradation of rhodamine B. Surface morphology was controlled by solution conditions, and as-fabricated films had rod, dense, and flower-like structure. We revealed the improvement of conductivity by photocatalytic activity of ZnO, influence of surface morphology on photo-degradation of rhodamine B, and relationship with conductivity and hydrogen production.
      PubDate: 2017-08-03T01:02:25.387902-05:
      DOI: 10.1002/asia.201700807
       
  • Synthesis of Pinpoint-Fluorinated Polycyclic Aromatic Hydrocarbons:
           Benzene Ring Extension Cycle Involving Microwave-Assisted SNAr Reaction
    • Authors: Kohei Fuchibe; Hisanori Imaoka, Junji Ichikawa
      Abstract: Fluoroarenes bearing no electron-withdrawing groups (non-activated fluoroarenes) readily underwent nucleophilic aromatic substitution with α-cyanocarbanions under microwave irradiation. The sequence (i) formylalkylation involving the cyanoalkylation of fluoroarenes, (ii) difluorovinylidenation, and (iii) Friedel–Crafts-type cyclization, afforded extended fluoroarenes by one benzene ring per cycle. Furthermore, the performance of multiple cycles successfully provided higher-order pinpoint-fluorinated polycyclic aromatic hydrocarbons (F-PAHs).Lords of the rings: Fluoroarenes bearing no electron-withdrawing groups (non-activated fluoroarenes) readily underwent nucleophilic aromatic substitution with α-cyanocarbanions under microwave irradiation. The sequence (i) formylalkylation involving cyanoalkylation of fluoroarenes, (ii) difluorovinylidenation, and (iii) Friedel–Crafts-type cyclization, afforded extended fluoroarenes by one benzene ring per cycle. Furthermore, the performance of multiple cycles successfully provided higher-order pinpoint-fluorinated polycyclic aromatic hydrocarbons (F-PAHs).
      PubDate: 2017-08-02T06:06:12.28865-05:0
      DOI: 10.1002/asia.201700870
       
  • Hydroarylation of 2-Aryloxybut-1-en-3-ynes via Pd/acid-catalyzed C-H bond
           activation: Concise Synthesis of 2,3-Bismethylene-2,3-dihydrobenzofurans
    • Authors: Yasunori Minami; Migumi Sakai, Takumi Sakamaki, Tamejiro Hiyama
      Abstract: We found an intramolecular exo-hydroarylation of 2-aryloxy-1,4-disilylbut-1-en-3-ynes via ortho-C-H bond activation under palladium(0) and acid catalysis to give 2,3-bis(silylmethylidene)-2,3-dihydrobenzofurans. The two silyl groups probably promote the reaction and play a key role in stabilizing the diene moiety in the product. The products are readily led to functionalized condensed cycles by the Diels-Alder reaction.
      PubDate: 2017-08-02T06:00:51.912892-05:
      DOI: 10.1002/asia.201701079
       
  • Efficient Copper-(N-Heterocyclic Carbene) Catalyzed Multicomponent
           Synthesis of Pyrroles
    • Authors: Abdul Majeed Seayad; Tuan Thanh Dang
      Abstract: Efficient Cu-NHC catalyzed syntheses of pyrroles via two and three-component coupling methods are described, for the first time. Various 1,2-, 1,2,3-, 1,2,3,5- and fully substituted pyrroles were readily accessible through suitable choice of ketone, primary amine and diol in a three-component reaction. The N-unsubstituted pyrrole formation is also feasible through a two-component reaction involving a β-amino alcohol and a ketone
      PubDate: 2017-08-01T21:00:45.067816-05:
      DOI: 10.1002/asia.201701045
       
  • In situ Assembly of Au Nanoclusters within Protein Hydrogel Networks
    • Authors: Liqiang Wang; Xingxing Jiang, Min Zhang, Minghui Yang, You-Nian Liu
      Abstract: We report a new approach of in situ assembling gold nanoclusters (AuCNs) into hydrogel networks by exploiting the triple roles of protein as a gelator, a reducing agent as well as a template. The strategy simply involves the mixing of BSA and AuCl4- under alkaline condition. The obtained AuCNs-protein nanocomposite hydrogels with injectable and moldable features can be made into semi-transparent films or N-doped C/Au composites. Our work demonstrates the feasibility of fabricating AuCNs in situ embedded hybrid hydrogels, which can work as multifunctional precursors for constructing diverse nanocomposite materials.
      PubDate: 2017-07-31T04:16:05.982994-05:
      DOI: 10.1002/asia.201700915
       
  • Nanostructured Three-Dimensional (3D) Assembly of 2D MoS2 and Graphene
           Directly Built from Acidic Graphite Oxide
    • Authors: Sunil P. Lonkar; Vishnu V. Pillai, saeed Alhassan
      Abstract: A 3D highly interconnected macroporous network of reduced GO having finely dispersed few-layered 2D MoS2 nanosheets was constructed through direct use of acidic graphite oxide (GO) for the first time. This facile and technological scalable process can afford an efficient electrocatalysts, anode materials, HDS catalysts at lower cost and can circumvent the poor thermal stability and recyclability of the material. The strategy provided here can be the basis to design and develop practical processes to address the ultimate goal of large-scale manufacturing of hybrids composed of 2D materials for various energy and catalysis applications.
      PubDate: 2017-07-30T21:20:40.481734-05:
      DOI: 10.1002/asia.201701003
       
  • Multicavity Metallosupramolecular Architectures
    • Authors: James David Crowley; Dan Preston, Roan A. S. Vasdev
      Abstract: Discrete metallosupramolecular systems are often macrocyclic or cage-like architectures with an accessible internal cavity. Guest molecules can reside within these cavities and much of the interest in these systems is derived from these fascinating host-guest interactions. A range of potential applications stem from the ability of these metallosupramolecular architectures to encapsulate guests. These applications include catalysis or acting as molecular reaction flasks, the molecular scavenging of pollutants, storage of reactive species, and drug delivery. Multicavity metallosupramolecular architectures combine the ability of large hollow assemblies to bind multiple guests concurrently with the binding specificity associated with small cages. A variety of different approaches to generating separate compartments within a single metallosupramolecular assembly have emerged. These include interpenetrated cages, cages with polytopic ligands that have a long backbone, and molecules that have two or more clefts. This review examines these approaches, and highlights key contributions to the field.
      PubDate: 2017-07-29T00:01:17.655206-05:
      DOI: 10.1002/asia.201700948
       
  • Metal-free, Initiator-free Graphene Oxide Catalyzed Trifluoromethylation
           of Arenes
    • Authors: Jingyu Zhang; Yun Yang, Jingxian Fang, Guo-Jun Deng, Hang Gong
      Abstract: The direct C-H trifluoromethylation of arenes catalyzed by graphene oxide (GO) under safe conditions is described. This strategy is metal free, initiator free, safe, and scalable. It employs a readily available CF3 source and could easily control the reaction to obtain a mono-trifluorinated product. This method opened a new field for GO-catalyzed chemistry.
      PubDate: 2017-07-26T21:26:13.068769-05:
      DOI: 10.1002/asia.201700939
       
  • Perfluoroalkylated Calix[4]pyrrole: fluoride ion extraction from aqueous
           medium
    • Authors: Sinchan Maji; Debaprasad Mandal
      Abstract: Octaalkenyl calix[4]pyrrole (CH₂=CH(CH₂)₂)₈C4P) is highly useful for post functionalization towards design of different calix[4]pyrrole with desired functionality. Functionalization with perfluoroalkyl chains [CF₃(CF₂)n; Rfn] gives perfluoroalkyl calix[4]pyrroles (Rfn(CH₂)4)₈C4P; n=6, 8), having>60% fluorine content which creates hydrophobic environment inside the calix[4]pyrrole cavity and recognizes fluoride and chloride ion from solution as well as solid. Fluoride ion is extracted efficiently from aqueous CsF and TBAF solutions by (Rf₆(CH₂)₄)₈C4P as droplets. Fluorous chain generates hydrophobic environment which destroys the hydration shell associated with anion and separates out fluoride ion as droplets from aqueous medium. Further fluoride ion competitively replaces chloride ion from (Rf₆(CH₂)₄)₈C4P cavity.
      PubDate: 2017-07-25T21:25:36.51229-05:0
      DOI: 10.1002/asia.201700897
       
  • Fluorescence and Sensing Applications of Graphene Oxide and Graphene
           Quantum Dots: A Review
    • Authors: Peng Zheng; Nianqiang Wu
      Abstract: Graphene oxide and graphene quantum dots are attractive fluorophores, which are inexpensive, non-toxic, photo-stable, water-soluble, biocompatible and environmentally friendly. They find extensive applications in fluorescent biosensors and chemi-sensors, in which they either serve as fluorophores or quenchers. As fluorophores, they display the tunable photoluminescence emission and the "Giant Red-Edge Effect". As quenchers, they exhibit a remarkable quenching efficiency via either electron transfer or Förster resonance energy transfer (FRET) process. In this review article, the origin of fluorescence and the mechanism of excitation wavelength-dependent fluorescence of graphene oxide and graphene quantum dots are discussed. The sensor design strategies based on graphene oxide and graphene quantum dots are presented. The applications of such sensors in health care, environment, agriculture and food safety are highlighted.
      PubDate: 2017-07-25T14:20:22.942597-05:
      DOI: 10.1002/asia.201700814
       
  • Precisely designed isopeptide bridge-crosslinking endows artificial
           hydrolases with predominant stability and catalytic activity under extreme
           denaturing conditions
    • Authors: Yu Bai; Chao Wang, Guodong Liang, Wenqing Lai, Huifang Xue, Yanbo Ling, Maosheng Cheng, Keliang Liu
      Abstract: Enzymes normally lose their activities under extreme conditions due to the dissociation of their active tertiary structure. If an enzyme could maintain its catalytic activity under non physiological or denaturing conditions, it might be used in more applications in the pharmaceutical and chemical industries. Recently, we reported a coiled-coil six-helical bundle (6HB) structure as a scaffold for designing artificial hydrolytic enzymes. Here, intermolecular isopeptide bonds were incorporated to enhance the stability and activity of such biomolecules under denaturing conditions. These isopeptide bridge-tethered 6HB enzymes showed exceptional stability against unfolding and retained or even had increased catalytic activity for a model hydrolysis reaction under thermal and chemical denaturing conditions. Thus, isopeptide bond-tethering represents an efficient route to construct ultrastable artificial hydrolases, with promising potential to maintain biocatalysis under extreme conditions.
      PubDate: 2017-07-25T08:25:34.126095-05:
      DOI: 10.1002/asia.201701021
       
  • Covalent functionalization of graphene by nucleophilic addition reaction:
           synthesis and optical limiting property
    • Authors: Xiujuan Xu; Peiying Li, Lei Zhang, Xuejian Liu, Hao-Li Zhang, Qingzhao Shi, Baojiang He, Wenjuan Zhang, Zhan Qu, Pu Liu
      Abstract: Covalent functionalization of reduced graphene oxide (rGO) was prepared by conjugated polymers with different monomers, using nucleophilic addition reaction between rGO and nitrogen anions. Three conjugated polymers containing tetraphenylethylene, carbazole and phenyl groups were used, due to the π-π interaction and "polymer wrapping" effect, the dispersion stability of rGO was improved. Even the reacting site in polymers were same to each other, there were great differences in the reactivity of the polymers, the dispersion stability of the resultant composites, and also the OL performances of the resultant composites. The differences maybe contributed to their π-conjugated structure and steric hindrance of the moiety in polymer skeleton, which was hardly mentioned before. Besides, the resultant materials rGO-P1 and rGO-P3 both showed excellent OL response even at 4 μJ, these behaviors enabled their potential application in photonic and optoelectronic devices to protect human eyes or optical sensors from damage by intense laser irradiation.
      PubDate: 2017-07-21T04:10:50.570738-05:
      DOI: 10.1002/asia.201700899
       
  • Synthesis, Structure and Properties of Near-Infrared
           [b]-Phenanthrene-Fused BF2 Aza-dipyrromethenes
    • Authors: Jiuen Cui; Wanle Sheng, Qinghua Wu, Changjiang Yu, Erhong Hao, Petia Bobadova-Parvanova, Marie Storer, Abdullah M. Asiri, Hadi M. Marwani, Lijuan Jiao
      Abstract: A new class of phenanthrene-fused BF2 aza-dipyrromethene (aza-BODIPY) dyes has been synthesized through tandem Suzuki reaction and oxidative ring-fusion reaction or the Palladium catalyzed intramolecular C-H activation reaction. These phenanthrene-fused aza-BODIPY dyes are highly photostable and display markedly red shifted absorption (up to 771 nm) and emission bands (around 800 nm) in the Near-Infrared (NIR) region. Density functional theory (DFT) calculation and cyclic voltammetry studies indicate that upon annulations, the more-pronounced stabilization of the LUMO is the origin of bathochromic shift of the absorption and high photostability.
      PubDate: 2017-07-20T21:16:01.013597-05:
      DOI: 10.1002/asia.201700876
       
  • Micelle Directing synthesis of the Ag-doped WO3 and MoO3 Composite for the
           Photocatalytic Water Oxidation and Organic Dyes Adsorption
    • Authors: Nasen Bate; Hongfei Shi, Li Chen, Jiabo Wang, Shasha Xu, Weilin Chen, Jianping Li, En-Bo Wang
      Abstract: In this paper, Ag-doped WO3 (MoO3) composite has been prepared by a simple micelle directed method and high temperature sintering route. The as-prepared samples were characterized by XRD, ICP, TEM, XPS, DRS, BET, PL and EIS techniques. The photocatalytic experiments reveal that their oxygen production rates are up to 95.43 μmol (75.45 μmol) for Ag-doped WO3 (MoO3), which is 9.5 (7.3) times higher than that of pure WO3: 9.012 μmol (MoO3: 9.00 μmol) under visible light illumination (λ ≥ 420 nm), respectively. The improvement of photocatalytic activities are attributed to the enhancement of their visible-light absorption and the separation efficiency of photogenerated carriers by Ag doping. Moreover, Ag-doped WO3 (MoO3) also shows excellent adsorption property for RhB and MB in aqueous solution, and the maximum Qt towards RhB and MB are 822 and 820 mg·g-1 for Ag-doped WO3, and 642 and 805 mg·g-1 for Ag-doped MoO3, respectively.
      PubDate: 2017-07-20T07:11:22.020513-05:
      DOI: 10.1002/asia.201700951
       
  • Phosphorylated Polyacrylonitrile Fiber as an Efficient and Greener
           Acetalization Catalyst
    • Authors: Gang Xu; Jian Cao, Yali Zhao, Lishuo Zheng, Minli Tao, Wenqin Zhang
      Abstract: A novel solid acid catalyst (PANEAPF) was developed by immobilization of phosphoric acid on polyacrylonitrile fiber via covalent bond. Various characterization techniques such as elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. were utilized to confirm the successful grafting and the stability of the fiber catalysts during application. The PANEAPF showed high catalytic activity in the acetalization of aldehydes due to the high utilization efficiency of its functionalized acid sites. Besides, the strong polarity micro-environment in the surface layer of the PANEAPF make it highly suitable for catalytic application no matter in water or alcohol. Furthermore, the fiber catalyst can be applied to acetalization of aldehydes in a continuous flow process at room temperature, and shows excellent reactivity and superior recyclability (over 20 times). In a word, many advantages of the PANEAPF such as simple preparation, convenient acid amount regulatability, high durability, and eco-friendly process make it very attractive for fixed-bed reactors in chemical industry.
      PubDate: 2017-07-20T04:18:03.736466-05:
      DOI: 10.1002/asia.201700846
       
  • Robust Acenaphthoimidazolylidene Palladacycles: Highly Efficient Catalysts
           for the Amination of N-heteroaryl Chlorides
    • Authors: Tao Tu; Qinyue Deng, Yang Zhang, Haibo Zhu
      Abstract: A series of robust N-heterocyclic carbene palladacycles have been successfully developed, which exhibited high catalytic activity and selectivity toward the challenging amination of N-heteroaryl chlorides. Diverse primary and secondary amines are fully compatible with our new developed catalytic system. Remarkably, no double amination products could be detected when primary amines were utilized in our catalytic transformation. Furthermore, the protocol has been successfully extended to synthesize Rosiglitazone, a clinical drug for diabetes mellitus, highlighting its potential pharmaceutical feasibility.
      PubDate: 2017-07-18T13:30:28.2589-05:00
      DOI: 10.1002/asia.201700877
       
  • Natural compounds in cancer prevention: effects of coffee extracts and
           their main polyphenolic component 5-CQA on oncogenic Ras proteins
    • Authors: Alessandro Palmioli; Carlotta Cairamelli, Renata Tisi, Michela Spinelli, Gaia De Sanctis, Elena Sacco, Cristina Airoldi
      Abstract: Recent epidemiological studies demonstrate that consumption of healthy foods, especially rich in polyphenols content, might reduce the incidence of cancer and degenerative diseases. In particular, chlorogenic acids (CGAs) occur ubiquitously in food, representing the most abundant polyphenols in the human diet. A number of CGA beneficial biological effects, including anti-inflammatory activity, anti-carcinogenic activity and protection against neurodegenerative diseases have been reported. However, the molecular mechanisms at the basis of these biological activities have not yet been investigated in depth. By combining NMR spectroscopy, molecular docking, surface plasmon resonance and ex vivo assay on Ras-dependent breast cancer MDA-MB-231 cell line, we contributed to the elucidation of the molecular bases of the activity of CGAs and natural extracts from green and roasted coffee beans as chemo-protective dietary supplements.
      PubDate: 2017-07-18T07:15:36.045804-05:
      DOI: 10.1002/asia.201700844
       
  • A pyridoindole based multifunctional bioprobe: pH-induced fluorescence
           switching and specific targeting of lipid droplets
    • Authors: Bahadur Sk; Pilendra Thakre, Raghuvir Singh Tomar, Abhijit Patra
      Abstract: A versatile fluorescent probe, PITE, based on alkyl substituted pyridoindole (PI) and tetraphenylethylene (TE) exhibiting facile pH-induced fluorescence switching in solution, nanoparticles and solid state is presented. Strong fluorescence in the solid state besides solution and aggregated state allow sensing of toxic acid vapor. Fluorescence "off-on" switching of PITE by exposing to trifluoracetic acid and triethylamine vapor is visualized through naked eyes. A unified picture of switchable fluorescence of PITE is obtained by comprehensive spectroscopic investigations coupled with quantum mechanical calculations. Strong fluorescence, large Stokes shift, high photostability and biocompatibility of PITE makes it a viable probe for sub-cellular imaging. Extensive fluorescence microscopic studies employing organisms including lower and higher eukaryotes reveal specific localization of PITE to lipid droplets (LDs). It has been known that LDs are dynamic sub-cellular organelles linked to various physiological processes and human diseases. Hence, the specific detection of LDs in diverse organisms is important to biomedical research and health care. Isolation of LDs and subsequent colocalization studies ascertain selective targeting of LDs by easily affordable, lipophilic bioprobe, PITE. Thus, PITE turns out to be a promising multifunctional probe for chemo-sensing as well as selective tracking of LDs.
      PubDate: 2017-07-18T07:15:29.678489-05:
      DOI: 10.1002/asia.201700898
       
  • PET-based halogen-free photosensitizers: covalent meso-aryl as electron
           donors to effectively induce the formation of excited triplet state and
           singlet oxygen for BODIPY compounds
    • Authors: Xian-Fu Zhang; Nan Feng
      Abstract: Pristine BODIPY compounds have negligible efficiency to generate excited triplet state and singlet oxygen. In this report we show that attaching a good electron donor to BODIPY core can lead to the singlet oxygen formation up to 58% quantum efficiency. For this purpose, BODIPYs with meso-aryl (phenyl, naphthyl, anthryl, and pyrenyl) were synthesized and characterized. The fluorescence, excited triplet state and singlet oxygen formation properties for these compounds were measured in various solvents by UV-vis absorption, steady-state and time-resolved fluorescence methods, as well as laser flash photolysis technique. In particular, the presence of anthryl and pyrenyl showed substantial enhancement on the singlet oxygen formation ability of BODIPY up to 58% and 34% quantum efficiency respectively, due to their stronger electron donating ability. Upon the increase in singlet oxygen formation, the fluorescence quantum yield and lifetime values of an aryl-BODIPY showed concomitant decrease. The increase in solvent polarity enhances singlet oxygen generation but decreases fluorescence quantum yield. The results are explained by the presence of intramolecular photoinduced electron transfer from the aryl moiety to BODIPY core. This method of promoting T1 formation is very different from the traditional heavy atom effect by I, Br or transition metal atoms. This type of novel photosensitizers may find important applications in organic oxygenation reactions and photodynamic therapy of tumors.
      PubDate: 2017-07-13T05:31:31.615953-05:
      DOI: 10.1002/asia.201700794
       
  • Complexation Between (O-methyl)6-2,6-Helic[6]arene and Tertiary Ammonium
           Salts: Acid-Base/Chloride Ion Responsive Host-Guest Systems and Synthesis
           of [2]Rotaxane
    • Authors: Chuan-Feng Chen; Qiang Shi, Ying Han
      Abstract: Complexation between (O-methyl)6-2,6-helic[6]arene and a series of tertiary ammonium salts was described. It was found that the macrocycle could form stable complexes with the tested aromatic and aliphatic tertiary ammonium salts, which were evidenced by 1H NMR spectra, ESI mass spectra and DFT calculations. Especially, the binding and release process of the guests in the complexes could be efficiently controlled by acid/base or chloride ion, which represents the first acid-base and chloride ion responsive host-guest systems based on the macrocyclic arenes and protonated tertiary ammonium salts. Moreover, the first 2,6-helic[6]arene-based [2]rotaxane was also synthesized by the condensation between the host-guest complex and isocyanate.
      PubDate: 2017-07-13T05:31:10.67366-05:0
      DOI: 10.1002/asia.201700857
       
  • Stereoselective synthesis of pillar[4]arene[1]cis-diepoxy-p-dione and its
           X-Ray crystal structure of host‒guest system
    • Authors: Chengyou Han; Dezhi Zhao, Tian Li, Daofeng Sun
      Abstract: Herein we successfully develop a novel route to give rise to polarity for the pillararenes by the introduction of oxygenated functionalities into pillar[5]arene to stereoselectively synthesize the pillar[4]arene[1]cis-diepoxy-p-dione. Its host‒guest properties with different dinitrile molecules were also investigated and characterized by NMR and X-ray crystallography.
      PubDate: 2017-07-13T03:25:20.420212-05:
      DOI: 10.1002/asia.201700791
       
  • Controllable synthesis of ultra-thin NiCo2O4 nanosheet incorporated
           composite nanotubes towards efficient oxygen reduction
    • Authors: Yunpeng Huang; Fen Cui, Yan Zhao, Jian Bao, Jiabiao Lian, Yuanguo Xu, Tianxi Liu, Hua-Ming Li
      Abstract: Exploring non-precious metal-based ORR electrocatalysts featuring high efficiency, low cost and environmental friendliness is of great importance for the broad applications of fuel cells and metal-air batteries. In this work, one-dimensional (1D) SnO2 nanotubes (SNT) deposited with ultra-thin NiCo2O4 nanosheets was successfully fabricated through a productive electrospinning technique followed by sintering and low-temperature co-precipitation strategy. This hierarchically engineered architecture has ultrathin NiCo2O4 nanosheets uniformly and fully erecting on both walls of tubular SNT, which manifests improved electrochemical activity as oxygen reduction reaction (ORR) catalyst in terms of positive onset potential and high current density, as well as superior tolerance to crossover effects and long-term durability with respect to the commercial Pt/C catalyst. The excellent performance of SNT@NiCo2O4 composites may originate from their rationally designed hierarchical tubular nanostructure with completely exposed active sites and interconnected 1D networks for efficient electron and electrolyte transfer, making this composite nanotubes promising candidate to replace Pt-based catalysts for practical fuel cell and metal-air battery applications.
      PubDate: 2017-07-12T02:40:20.546731-05:
      DOI: 10.1002/asia.201700750
       
  • Molecular design of thermally activated delayed fluorescent emitters using
           2,2'-bipyrimidine as an acceptor in donor-acceptor structure
    • Authors: Hee-Jun Park; Si Hyun Han, Jun Yeob Lee
      Abstract: D-A-D type thermally activated delayed fluorescence (TADF) emitters, 5,5'-bis(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-2,2'-bipyrimidine (Ac-bpm) and 5,5'-bis(4-(10H-phenoxazin-10-yl)phenyl)-2,2'-bipyrimidine (Px-bpm), based on 2,2'-bipyrimidine accepting unit were developed and their TADF devices were fabricated. The orthogonal geometry between the donor unit and the 2,2'-bipyrimidine accepting core facilitated a HOMO/LUMO spatial separation, thus realizing thermally activated delayed fluorescence. They exhibited electroluminescence ranging from green to yellow, depending on the donor unit, with a maximum external quantum efficiencies of up to 17.1%.
      PubDate: 2017-07-11T00:40:27.335785-05:
      DOI: 10.1002/asia.201700889
       
  • Sequential Dy(OTf)3-Catalyzed Solvent-Free Per-O-Acetylation and
           Regioselective Anomeric De-O-Acetylation of Carbohydrates
    • Authors: Yi-Ling Yan; Jiun-Rung Guo, Chien-Fu Liang
      Abstract: Dysprosium(III) trifluoromethanesulfonate-catalyzed per-O-acetylation and regioselective anomeric de-O-acetylation of carbohydrates can be tuned by adjusting the reaction medium. In this study, per-O-acetylation of unprotected sugars by using a near stoichiometric amount of acetic anhydride under solvent-free conditions resulted in the exclusive formation of acetylated saccharides as anomeric mixtures, whereas anomeric de-O-acetylation in methanol resulted in a moderate to excellent yield. Reactions with various unprotected monosaccharide or disaccharide followed by a semi-one-pot sequential conversion into the corresponding acetylated glycosyl hemiacetal also resulted in high yields. Furthermore, the obtained hemiacetals could be successfully transformed into trichloroimidates following Dy(OTf)3-catalyzed glycosylation
      PubDate: 2017-07-08T06:20:21.69586-05:0
      DOI: 10.1002/asia.201700867
       
  • Gly-Decorated Praseodymium-Stabilized Nanosized Selenotungstate Cluster:
           Synthesis, Structure, and Oxidation Catalysis
    • Authors: Jingyang Niu; Ling Yang, jipeng Guo, Li Li, Qisen Liu, Pengtao Ma, Jingping Wang
      Abstract: A flexible one-pot strategy exploiting pyramidal SeIV heteroatom is employed for the assembly of praseodymium-containing gly-decorated polyoxotungstate [{Pr3(H2O)10[Se2W22O76(gly)2]}2(Se2W7O30H2)]18- (1a), which is constructed from one {Se2W7O30H2} unit and two identical {Pr3(H2O)10[Se2W22O76(gly)2]} units. Furthermore, the catalytic performance of Cs2Na4H12[{Pr3(H2O)10[Se2W22O76(gly)2]}2 (Se2W7O30H2)]∙25H2O (1) for alkenes epoxidation with hydrogen peroxide was investigated under mild reaction conditions. and the experimental results suggest that compound 1 exhibit good catalytic performance for the epoxidation of cyclooctene.
      PubDate: 2017-07-01T00:05:57.920963-05:
      DOI: 10.1002/asia.201700801
       
  • Various Current Responses of Single Ag Nanoparticle Collisions on Au
           Ultramicroelectrode Depending on Collision Condition
    • Authors: Seon Kyu Mun; Sangmin Lee, Dong Young Kim, Seong Jung Kwon
      Abstract: Collisions of silver (Ag) nanoparticles (NPs) with a more electrocatalytic gold (Au) or platinum (Pt) ultramicroelectrode (UME) surface have been observed using an electrochemical method. Depending on the applied potential to the UME, the current response of Ag NPs collision onto the UME resulted in various shape changes. A staircase decrease, a blip decrease, and a blip increase of the hydrazine oxidation current were obtained at an applied potential of 0.33 V, 0.80 V, and 1.3 V, respectively. Different behaviors of Ag NP collision on the UME surface were suggested for each shape of current response. Ag NP attachment which hindered the diffusion flux to the UME caused a staircase decrease of electrocatalytic current. Instantaneous blocking of the hydrazine oxidation by Ag NP collision and, following recovery of the current via oxidation of Ag NP caused a blip decrease of electrocatalytic current. The formation of higher oxidation state of Ag on the Ag NP and its electrocatalytic hydrazine oxidation resulted in a blip increase of the electrocatalytic current. The analysis of the current response for the single NP collision experiment can be a useful tool to understand the various behaviors of NPs on the electrode surface.
      PubDate: 2017-06-29T12:05:34.711327-05:
      DOI: 10.1002/asia.201700770
       
  • New Promising Method for the Challenging Synthesis of
           5-Acyl-2-Amino-3-Cyanothiophenes: Chemisry and Fluorescent Properties
    • Authors: Kseniya I. Lugovik; Alexander K. Eltyshev, Enrico Benassi, Nataliya P. Belskaya
      Abstract: Independent of the substrate structure and reaction conditions, 2-cyano-3-aminothioacrilonitriles, which contains two active electrophilic centers, were shown to interact with various active halo methylene compounds under mild conditions to afford 5-acyl-2-amino-3-cyanothiophenes as the only products. A series of new polyfunctional thiophene derivatives with a rare combination of functionalities were synthesized and their photophysical properties were experimentally and computationally investigated. The calculated electronic characteristics of the ground and excited states were compared to the experimental results, which provided a good understanding of the relationship between the optoelectronic properties and the molecular structures. After absorption of light quanta, the systems populate an intramolecular charge transfer (ICT) Franck-Condon state, and emission occurs from a twisted ICT (TICT) minimum.
      PubDate: 2017-06-24T04:47:32.424396-05:
      DOI: 10.1002/asia.201700721
       
  • Catalytic oxidation of alcohol to carboxylic acid with hydrophobic cobalt
           catalyst in hydrocarbon solvent
    • Authors: Song Shi; Meng Liu, Li Zhao, Min Wang, Chen Chen, Jin Gao, Jie Xu
      Abstract: A hydrophobic cobalt catalyst was synthesized and proved to be effective in the alcohol oxidation under the assistance of hydrocarbon solvent with oxygen as the terminal oxidant. A series of catalyst with different water contact angles was applied to investigate the hydrophobic effect. Further insight in to the reaction process was researched by reaction kinetics, isotopic effect, etc. It showed that thehydrocarbon solvent participated in the alcohol oxidation, andwith the aid of the in-situ generated free radicals, the α-C-H bond was smoothly activated and the alcohol was converted to carbonyl compounds. The hydrophobic effect promoted the alcohol oxidation through affecting the solvent oxidation.
      PubDate: 2017-06-19T07:15:57.293489-05:
      DOI: 10.1002/asia.201700717
       
  • Programmed Site-selective direct Palladium Catalyzed Arylations of
           Thieno[3,2-b]thiophene
    • Authors: Tung Thanh Dang; Thi Minh Ha Vuong, Hien Nguyen, Didier Villemin, Thanh Tin Le, Hung Huy Nguyen
      Abstract: Mono-, di-, tri- and tetra-arylated thieno[3,2-b]thiophenes were synthesized by direct site-selective Pd-catalyzed C-H activation reactions with various aryl bromides in the presence of a phosphine-free Pd(OAc)2/KOAc catalyst system in DMAc. The arylation of 2-arylthieno[3,2-b]thiophen¬e took place at the C-3 position when the 2-aryl substituents bear electron-withdrawing groups, and at the C-5 position when they are bulky and possess electron-donating groups
      PubDate: 2017-06-01T04:20:26.568113-05:
      DOI: 10.1002/asia.201700562
       
 
 
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