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  Subjects -> CHEMISTRY (Total: 902 journals)
    - ANALYTICAL CHEMISTRY (55 journals)
    - CHEMISTRY (636 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
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    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (636 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 14)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 29)
ACS Catalysis     Hybrid Journal   (Followers: 49)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 27)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 42)
ACS Nano     Hybrid Journal   (Followers: 321)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 25)
Acta Chemica Iasi     Open Access   (Followers: 6)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 62)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 77)
Advances in Chemical Science     Open Access   (Followers: 20)
Advances in Chemistry     Open Access   (Followers: 25)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20)
Advances in Drug Research     Full-text available via subscription   (Followers: 25)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 27)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 4)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 8)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
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: 22)
American Journal of Chemistry     Open Access   (Followers: 32)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 15)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 37)
Angewandte Chemie     Hybrid Journal   (Followers: 185)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 268)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 26)
Applied Surface Science     Hybrid Journal   (Followers: 34)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 3)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 378)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
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: 2)
Biomacromolecules     Hybrid Journal   (Followers: 24)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 138)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 92)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 19)
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: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 25)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 11)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 25)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 13)
Cellulose     Hybrid Journal   (Followers: 11)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 75)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 27)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 216)
Chemical Science     Open Access   (Followers: 28)
Chemical Technology     Open Access   (Followers: 35)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 58)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 22)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 33)
Chemistry & Industry     Hybrid Journal   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 176)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 21)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 46)
Chemistry of Materials     Hybrid Journal   (Followers: 281)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 21)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
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: 12)
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: 11)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Cogent Chemistry     Open Access   (Followers: 2)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
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: 23)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access   (Followers: 1)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
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: 13)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 4)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 7)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 8)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal   (Followers: 1)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 9)
Current Science     Open Access   (Followers: 74)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 2)
Dalton Transactions     Full-text available via subscription   (Followers: 26)
Detection     Open Access   (Followers: 4)

        1 2 3 4 | Last

Journal Cover
Canadian Journal of Chemistry
Journal Prestige (SJR): 0.29
Citation Impact (citeScore): 1
Number of Followers: 11  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0008-4042 - ISSN (Online) 1480-3291
Published by NRC Research Press Homepage  [21 journals]
  • Elucidation of the mechanism and energy barrier for anesthetic triggered
           membrane fusion in model membranes
    • Authors: Trinh T. Nguyen, David T. Cramb
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Membrane fusion is vital for cellular function and is generally mediated via fusogenic proteins and peptides. The mechanistic details and subsequently the transition state dynamics of membrane fusion will be dependent on the type of the fusogenic agent. We have previously established the potential of general anesthetics as a new class of fusion triggering agents in model membranes. We employed two-photon excitation fluorescence cross-correlation spectroscopy (TPE-FCCS) to report on vesicle association kinetics and steady-state fluorescence dequenching assays to monitor lipid mixing kinetics. Using halothane to trigger fusion in 110 nm diameter dioleoylphosphatidylcholine (DOPC) liposomes, we found that lipid rearrangement towards the formation of the fusion stalk was rate limiting. The activation barrier for halothane induced membrane fusion in 110 nm vesicles was found to be ∼40 kJ mol−1. We calculated the enthalpy and entropy of the transition state to be ∼40 kJ mol−1 and ∼180 J mol−1 K−1, respectively. We have found that the addition of halothane effectively lowers the energy barrier for membrane fusion in less curved vesicles largely due to entropic advantages.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-02-08T08:00:00Z
      DOI: 10.1139/cjc-2018-0405
       
  • Response surface methodological optimization of batch Cu(II) sorption onto
           succinic acid functionalized SiO2 nanoparticles
    • Authors: Amr A. Yakout, Medhat A. Shaker, Khalid Z. Elwakeel, Wael Alshitari
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Functionalizing nanosilica (n-SiO2) particles with suitable active organic moiety leads to the formation of surfaces with precisely controlled physical and chemical characteristics. In this work, a novel nanosorbent (31 ± 2.4 nm), namely succinic acid functionalized nanosilica (n-SiO2@SA), was synthesized via a simple protocol using microwave irradiation to remove Cu(II) ions from aqueous media. The successful functionalization of n-SiO2 was confirmed by FTIR, and the thermal stability of n-SiO2@SA was investigated by TGA study. Other techniques, including HRTEM, DLS and zeta-potential, were utilized to investigate the chemical, surface, and morphological properties of the fabricated n-SiO2@SA. The response surface methodology (RSM) combined with three-level, three-factorial Box–Behnken design (BBD) was applied to optimize the multivariable sorption system using data obtained from 17 batch runs to reach 98.9% of Cu(II) ion removal. The predicted optimal conditions were as follows: contact time = 30 min, pH = 7.1, initial Cu(II) concentration = 317.5 mg L−1, and sorbent dose = 15 mg at which the maximum sorption capacities for n-SiO2 and n-SiO2@SA were 209.3 and 386.4 mg g−1, respectively, at 25 °C, thus supporting the validity of functionalization process. Non-linear regression and linear least-squares methods confirm the suitability of Langmuir model to describe the experimental endothermic, feasible, and chemisorption data, whereas the normalized standard deviation Δq% recommends the pseudo second-order kinetic model to represent the kinetic data. Real Cu-contaminated wastewaters were used to examine n-SiO2@SA nanosorbent for removing Cu(II) ions.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-02-07T08:00:00Z
      DOI: 10.1139/cjc-2018-0086
       
  • Copper iodide and ZnO nanoparticles catalyzed multicomponent synthesis of
           1,3-cyclopentadiene: study of antioxidant activity
    • Authors: Elham Ezzatzadeh, Zinatossadat Hossaini, Ali Varasteh Moradi, Masoomeh Salimifard, Saeid Afshari-Sharif Abad
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Zinc oxide (ZnO) nanoparticles, as a simple and recyclable catalyst, were easily synthesized and used for the synthesis of 1,3-cyclopentadiene derivatives by a four-component reaction of terminal alkynes, sulfonyl azides, activated acetylenic compounds, and isocyanides in the presence of copper iodide in acetonitrile at room temperature. In these reactions, 1,3-cyclopentadiene derivatives were obtained in good yield and in a short reaction time. In this research, antioxidant activity was investigated for the some newly synthesized compounds such as 5a–5d using the DPPH radical trapping and reducing potential tests of ferric ion and comparing results with synthetic antioxidants (TBHQ and BHT). In this study, compounds 5a–5d show good DPPH radical trapping and excellent reducing power of ferric ion.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-02-06T08:00:00Z
      DOI: 10.1139/cjc-2018-0154
       
  • Two temperature regimes of triplet transfer in the dissociation of the
           correlated triplet pair after singlet fission
    • Authors: Tia S. Lee, YunHui L. Lin, Hwon Kim, Barry P. Rand, Gregory D. Scholes
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The ability to undergo spin-allowed exciton multiplication makes singlet fission materials promising for photovoltaic applications. Here, we examine the separation of correlated triplet pairs, 1(T…T), in polycrystalline pentacene films via temperature-dependent transient absorption spectroscopy. Single wavelength analysis reveals a profound delay in 1(T…T) dynamics. Moreover, the dynamics of 1(T…T) exhibit temperature dependence, whereas other features show no discernable temperature dependence. Previous literatures have suggested that correlated triplet separation is mediated by a thermally activated hopping process. Surprisingly, we found that the time constants governing triplet pair separation display two distinct temperature-dependent regimes of triplet transport. The high temperature regime follows a thermally activated hopping mechanism. The experimentally derived reorganization energy and electronic coupling is verified by density matrix renormalization group quantum chemical calculations. In addition, we evaluated the low temperature regime and show that the trend can be modelled by a Miller–Abrahams-type model that incorporates the effects of energetic disorder. We conclude that the correlated triplet pair separation is mediated by thermally activated hopping or a disorder driven Miller–Abrahams-type mechanism at high and low temperature, respectively. We observe that crossover between two regimes occurs ∼226 K. We find the time constant for triplet–triplet energy transfer to be 1.8 ps at ambient temperature and 21 ps at 77 K.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-02-01T08:00:00Z
      DOI: 10.1139/cjc-2018-0421
       
  • Assessment of boron nitride nanotube materials using X-ray photoelectron
           spectroscopy
    • Authors: Michael B. Jakubinek, Keun Su Kim, Christa Homenick, Oltion Kodra, Steven Walker, Benoit Simard
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      With increasing prevalence of boron nitride nanotubes (BNNTs), the need for routine and reliable assessment methods is becoming more critical both for research studies and for quality control in nanotube manufacturing. The assessment of BNNT materials using X-ray photoelectron spectroscopy (XPS) is described here through analysis of raw-BNNT materials and three case studies showing modification of BNNTs by purification or chemical functionalization. Metrics indicative of the BN content of the material, with the simplest being the B:N ratio, are described and tracked to show evolution of BNNT materials during processing. Along with changes in the elemental composition and the content of BN, high-resolution spectra of the B 1s region also show clear evolution as BNNT materials are modified, which can be used as a measure of boron nitride content and quality to assess BNNT production, purification, and functionalization.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-02-01T08:00:00Z
      DOI: 10.1139/cjc-2018-0430
       
  • Facile synthesis of EDTA-functionalized halloysite nanotubes for the
           removal of methylene blue from aqueous phase
    • Authors: Mengmeng Zhang, Hongchao Yu, Bibo Chen
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      EDTA-functionalized halloysite nanotubes (EDTA-HNTs) were synthesized by a two-step method. The structures of the EDTA-HNTs were analyzed by Fourier-transform infrared spectra, X-ray diffraction, thermogravimetric analysis, and transmission electron spectroscopy. Then, the EDTA-HNTs were applied as adsorbents for the removal of methylene blue from aqueous phase. Adsorption of methylene blue onto EDTA-HNTs was investigated with respect to adsorbent dose, contact time, initial methylene blue concentration, and temperature. A maximum adsorption capacity of 115.8 mg/g for methylene blue onto EDTA-HNTs at room temperature was achieved. The adsorption kinetics could be described by the pseudo-second-order model. Both the Langmuir and Freundlich models were employed to describe the adsorption isotherms, and the results presented that the equilibrium data obeyed the Langmuir model. Thermodynamic parameters of ΔG0 and ΔH0 verified the spontaneous and exothermic nature of the methylene blue adsorption onto EDTA-HNTs. Moreover, the EDTA-HNTs could be facilely regenerated and efficiently reused, exhibiting a good prospect for the treatment of dye effluents.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-28T08:00:00Z
      DOI: 10.1139/cjc-2018-0247
       
  • Microfluidic encapsulation of SN-38 in block copolymer nanoparticles:
           
    • Authors: Danica Jensen, Yimeng Cao, Changhai Lu, Jeremy E. Wulff, Matthew G. Moffitt
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A gas–liquid microfluidic reactor was used to prepare polymer nanoparticles (PNPs) containing the drug 7-ethyl-10-hydroxy camptothecin (SN-38) from a series of poly(methyl caprolactone-co-caprolactone)-b-poly(ethylene oxide) (P(MCL-co-CL)-b-PEO) amphiphilic block copolymers with variable MCL content in the hydrophobic block. All three copolymers formed spheres with ∼20 nm core diameters by TEM, although some rigid rod-like aggregates were also formed by the PMCL-50 and PMCL-75 copolymers. SN-38 encapsulation efficiencies (EE = 2.7%–3.0%) and loading levels (DL = 2.0%–2.9%) were similar for the three copolymers. In vitro release kinetics became significantly slower as the MCL content increased, with release half times increasing monotonically from 3.4 to 6.2 h as the MCL content of the hydrophobic block increased from 50% to 100%. The ability to systematically tune release half times via controlled variation in the hydrophobic block composition, while maintaining constant PNP size and loading levels, represents an intriguing chemical handle for the optimization of SN-38 nanomedicines.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-15T08:00:00Z
      DOI: 10.1139/cjc-2018-0371
       
  • Novel enantioselective synthesis of (S)-ketamine using chiral auxiliary
           and precursor Mannich base
    • Authors: Seyed Jamaladdin Gohari, Abdollah Javidan, Abolghasem Moghimi, Mohammad Javad Taghizadeh, Maryam Iman
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Ketamine has been extensively used as an anesthetic drug. Chiral auxiliaries such as tert-butanesulfinamide (TBSA) can be used for the asymmetric synthesis of (S)-ketamine. Condensation of TBSA with ketones provides tert-butanesulfinylimines in consistently high yields. The tert-butanesulfinyl group actuates the imine for nucleophilic addition, is a potent chiral directing group, and after nucleophilic addition is easily dissociated by intervention with acid solution. To prepare 2-(N-piperidinomethyl)-1-phenylcyclohexylamine (1), we started with the cyclohexanone and using Mannich reaction achieved an aminoketone. Then, we made the sulfiniylamin (2) by the condensation of TBSA with aminoketone. By using salts such as Ti(OEt)4, we obtained N-tert-butanesulfinylketimine in 85% yield. Next, we provided a new chiral center (3) using Grignard reagent as nucleophile at −78 °C (80% yield). Finally, after many steps, the (S)-ketamine synthesized under ozonolysis conditions, with good yield and enantioselectivity (75% yield and 75% ee).
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-14T08:00:00Z
      DOI: 10.1139/cjc-2017-0731
       
  • Ruthenium-catalyzed ring-opening reaction of a
           3-aza-2-oxabicyclo[2.2.1]hept-5-ene with amines — an unexpected mode of
           ring-opening
    • Authors: Katrina Tait, Samuel Koh, Nicolas Blanchard, William Tam
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The ruthenium-catalyzed ring-opening reaction of a 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with amines was investigated. In the presence of an amine and a ruthenium catalyst, the N–O bond is cleaved, forming a ring-opened allylic alcohol product. Through a possible ruthenium-catalyzed redox isomerization, the allylic alcohol is transformed into a saturated carbonyl product. This unexpected mode of ruthenium-catalyzed ring-opening reaction of a 3-aza-2-oxabicyclo[2.2.1]hept-5-ene leads to the formation of a cyclopentanone derivative in moderate yields.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-14T08:00:00Z
      DOI: 10.1139/cjc-2018-0444
       
  • Peroxidase-like activity of palladium nanoparticles on hydrogen-bond
           supramolecular structures over a broader pH range and their application in
           glucose sensing
    • Authors: Nian Zhou, Seyin Zou, Li Zou, Ruidi Shen, Yamin Zhou, Liansheng Ling
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      To circumvent the complicated natural peroxidases, palladium nanoparticles embedded in melamine cyanurate (MCA-Pd NPs) were synthesized. MCA-Pd NPs catalyzed the oxidation of ABTS2– by H2O2, and the solution turned green, which could be quantified via a typical absorption peak at 420 nm. MCA-Pd NPs had high peroxidase-like activity in a wider pH range than that of natural peroxidases. MCA-Pd NPs were used to develop a colorimetric sensor for H2O2 over the pH range of 7.0 to 11.0, which had same linear range, and their linear regression equations had similar slopes. Moreover, MCA-Pd NPs were applied to establish the biosensor for glucose by using glucose oxidase (GOx); it had a linear range of 5.0–120 μmol/L, with a linear regression equation of A = 0.04926 + 0.00536C (C: μmol/L, R = 0.9960) and a detection limit of 0.3 μmol/L (3σ/slope). When we applied it to detect glucose level in human blood, satisfactory results were obtained.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-09T08:00:00Z
      DOI: 10.1139/cjc-2018-0302
       
  • Identifying absolute configurations of PCB atropisomers by comparison of
           their experimental specific rotations with their DFT calculated values
    • Authors: Oluwadamilola Daramola, John Cullen
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Nineteen enantiomer pairs of polychlorinated biphenyls (PCBs) with three or four chloro substituents about the central carbon–carbon bond form a stable subclass of compounds whose biological effects vary with their chirality. Optical rotations for this group of PCBs were determined from density functional calculations employing extended atomic orbital gauge invariant basis sets. A comparison of these results with the experimental ones found from the literature for 10 of the pairs enabled the identification of their absolute configurations as analytes in gas chromatography studies.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-09T08:00:00Z
      DOI: 10.1139/cjc-2018-0458
       
  • The effect of phenolic compounds on salicylaldimine nickel-catalyzed
           ethylene oligomerization
    • Authors: Jun Wang, Junyi Xie, Libo Wang, Yan Jiang, Na Zhang
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A salen nickel complex has been prepared in good yield with ethylenediamine, salicylaldehyde, and NiCl2·6H2O as raw materials. The structure of the complex was characterized by FTIR, 1H NMR, UV, and ESI-MS. Upon activation with methylaluminoxane (MAO), the precatalyst showed high activity for ethylene oligomerization. To reduce the simultaneous production of insoluble polymers during the nickel-catalyzed ethylene oligomerization, a series of phenolic compounds were introduced as modifiers for the production of linear α-olefins. The researched result showed that the phenolic compounds have a significant impact on the selectivity of oligomers and the concentration of polymers. With the increase of phenolic compounds, the content of polymers decreased and the distribution of oligomers gradually shifted toward lighter olefins. The sterically hindered 4-tert-butyphenol proved to be an especially efficient polymer-retarding modifier among the studied phenolic compounds in this work. Furthermore, the retarding effect of phenolic compounds toward insoluble polymers may be mainly related to their interaction with MAO, giving rise to larger MAO aggregates.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-08T08:00:00Z
      DOI: 10.1139/cjc-2018-0292
       
  • Copper nanoparticles supported on charcoal mediated one-pot
           three-component synthesis of N-substituted-2H-indazoles via consecutive
           condensation C–N and N–N bond formation
    • Authors: Reza Khalifeh, Faranak Karimzadeh
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      An efficient and straightforward protocol for direct synthesis of 2H-indazoles is achieved from consecutive condensation of 2-halobenzaldehydes, primary amines, and sodium azide catalyzed by heterogeneous copper nanoparticles on charcoal (Cu/C) is achieved. The recoverable heterogeneous copper nanoparticles on charcoal (Cu/C) catalyst exhibited an impressive activity for the title reaction without any additives (expensive ligands, etc.). A series of structurally diverse 2H-indazoles were prepared in good to excellent yields from easily accessible starting materials by employing this protocol.
      Citation: Canadian Journal of Chemistry
      PubDate: 2019-01-08T08:00:00Z
      DOI: 10.1139/cjc-2018-0428
       
  • Novel synthesis of 1,5-disubstituted-1,2,3-triazolines catalysed by Zepto
           magnetic microspheres under the influence of a rotating magnetic field
    • Authors: Priyanka Sharma, Srinivasu V. Vallabhapurapu, Wei H. Ho, Nanjundaswamy M. Hemmaragala
      Pages: 163 - 168
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 163-168, March 2019.
      The novel reactor has been designed to perform chemical reactions under the influence of a magnetic field generated by alternating magnetic poles as a function of time. The system was successfully employed to synthesize a series of 1,5-disubstituted-1,2,3-triazolines via the regioselective [3 + 2] cycloaddition reactions between alkyl/aryl azides and nitroolefins catalysed by Zepto (para magnetic ultra-blue carboxy functionalized) microspheres (bead diameter 2.5 μm). All of the reactions went smoothly without any adverse effect on nitro, cyano, thienyl, hydroxy, halogens, and ether functions at 25 ± 2 °C and afforded 82%–99% pure products at a magnetic field of 18.99 mT and an exposure time of 180–240 min. The influence of the magnetic force exerted on the magnetic materials was found to enhance the catalytic activity of microspheres. The catalyst could easily be separated by simple centrifugation, which could be reused for at least 15 runs with no loss in activity.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-10-30T07:00:00Z
      DOI: 10.1139/cjc-2018-0349
       
  • Inside-protonated 1-azaadamantane: computational studies on the structure,
           stability, and generation
    • Authors: Cory Beshara, Gennady Shustov
      Pages: 169 - 177
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 169-177, March 2019.
      Post Hartree–Fock and density functional theory methods have been employed to study inside-protonated 1-azaadamantane 7 and its complexes with the fluoride counterion (contact ion pairs) 10 and 11. The study also involved 1-azaadamantane 4, its outside-protonated form 8, and 1-azaadamantane radical cation 17. Inside-protonated 1-azaadamantane 7 is more than 82 kcal mol−1 less stable than out-isomer 8. The repulsive interaction between the internal N+–H group and the azaadamantane cage and a substantial deformation of this cage greatly weaken the C–N and C–C bonds and, consequently, lead to a low kinetic stability of in-ion 7 in the studied unimolecular and bimolecular reactions involving the removal of the encapsulated proton from the cage. Among these reactions, a 7 → 8 rearrangement through a reversible cage opening at the C–N bond was found to be the main transformation channel ([math] < 16 kcal mol−1) for in-ion 7. This rearrangement can be catalyzed by an external base, e.g., the fluoride anion. A 1,4-hydrogen migration in 1-azaadamantane radical cation 17 as a possible pathway to the inside-protonated 1-azaadamantane 7 was explored. It was found that this process has a prohibitively high activation barrier, [math]> 104 kcal mol−1, and is not able to compete with the α-C–C cleavage of the azaadamantane cage ([math] < 26 kcal mol−1).
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-06T08:00:00Z
      DOI: 10.1139/cjc-2018-0407
       
  • Replacing sulfonate by carboxylate: application of pyridyliminocarboxylato
           copper(II) complexes in rac-lactide polymerization and Chan–Evans–Lam
           coupling
    • Authors: Valérie Hardouin Duparc, Clémentine Dimeck, Frank Schaper
      Pages: 178 - 190
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 178-190, March 2019.
      Copper(II) complexes carrying pyridylmethyleneaminobenzoate or –propanoate ligands, LCuX, were prepared in one-pot reactions from pyridinecarboxaldehyde, aminobenzoic acid or β-alanine, and CuX2 (X = Cl, NO3, OAc, or OTf). All complexes were characterized by single-crystal X-ray diffraction studies and formed either dimers, tetramers, or coordination polymers. Attempted preparation of the respective alkoxide complexes, LCu(OR), was unsuccessful, but use of LCuX/NaOMe mixtures in rac-lactide polymerization indicated under some conditions coordination–insertion polymerization via a copper alkoxide as the mechanism. The complexes performed poorly in rac-lactide polymerization, showing low activities (12 h to completion at 140 °C), low to moderate heterotacticity (Pr = 0.6–0.8), and poor polymer molecular weight control (intramolecular transesterification). They were competent catalysts for Chan–Evans–Lam couplings with phenylboronic acid, without any indication of side reactions such as deboration or aryl homocoupling. The complexes were active in undried methanol, without addition of base, ligand, or molecular sieves. Aniline, n-octylamine, and cyclohexylamine were coupled quantitatively under identical reaction conditions. There is only little influence of the anion on activities (less than a factor of 2) but a strong influence on induction periods. The complexes were not active in CEL coupling with alcohols, phenols, or alkylboronic acids.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-07T08:00:00Z
      DOI: 10.1139/cjc-2018-0402
       
  • Efficient reduction of nitroarenes in water catalyzed by reusable Pd
           nanoparticles immobilized on chitosan-functionalized graphene oxide
    • Authors: Mosayeb Sarvestani, Roya Azadi
      Pages: 191 - 196
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 191-196, March 2019.
      Graphene oxide was functionalized with chitosan for palladium immobilization (GO–Chit–Pd), which was used as an efficient catalyst for the reduction of aromatic nitro compounds using sodium borohydride in water. To achieve the best catalytic efficacy, various parameters such as temperature, solvent, mole ratio of hydrogen sources, and the amount of catalyst were optimized. The method has been applied to the reduction of a broad range of nitroarenes with different properties. The easy purification, convenient operation, environmental friendliness, and high product yields render this method viable for use. The nanocatalyst can be easily separated and efficiently recovered and reused for multiple cycles without appreciable loss in its catalytic activity.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-12-13T08:00:00Z
      DOI: 10.1139/cjc-2018-0011
       
  • Impact of method parameters on the performance of suspect screening for
           the identification of trace organic contaminants in surface waters
    • Authors: Pedro A. Segura, Mathieu Racine, Alexia Gravel, Emmanuel Eysseric, Anne-Marie Grégoire, Diane Rawach, François-Xavier Teysseire
      Pages: 197 - 211
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 197-211, March 2019.
      The performance of a suspect screening method to detect diverse small-molecule trace organic contaminants (TOCs) was systematically evaluated using a set of 39 model compounds. Experiments showed that ionization efficiency, ion transfer parameters, and chromatography could affect the detection of TOCs. As expected, compounds with low ionization yields and poorly retained compounds in chromatographic columns are more difficult to identify in the samples at environmental concentrations. Similarly, TOCs with large deviations from the average mass of the compounds screened were not transmitted efficiently in the mass spectrometer thus negatively affecting their detection. The suspect screening method was validated in terms of recovery and limits of identification of the model compounds using three different types of solid-phase extraction cartridges (reversed phase with polar groups, mixed-mode anion exchange, and mixed mode cation exchange). Experiments showed that more than two-thirds of the model compounds had recoveries>75% with each of the three cartridges, and comparison of limits of identification showed that more than one-half of the model compounds could be identified at concentrations between 6 and 100 ng L−1. However, it was observed that the amount of co-extracted compounds was higher in mixed-mode ion exchangers compared with the reversed-phase cartridge. Application of the suspect screening method using the three different cartridges to surface water samples showed that between 0 to 3% of the positive matches found by the peak identification algorithm were classified as probable structures. Solutions to improve suspect screening of TOCs are proposed and discussed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-15T08:00:00Z
      DOI: 10.1139/cjc-2018-0298
       
  • CO2 involved synthesis of quinazoline-2,4(1H,3H)-diones in water using
           melamine as a thermoregulated catalyst
    • Authors: Guo-Ying Zhao, Ling-Ling Mu, Latif Ullah, Meng Wang, Hong-Ping Li, Xin-Xin Guan
      Pages: 212 - 218
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 212-218, March 2019.
      In this study, pharmaceutically relevant quinazoline-2,4(1H,3H)-diones were synthesized eco-efficiently by cycloaddition of CO2 and 2-aminobenzonitrile in water, catalyzed by melamine as a thermoregulated catalyst. Quinazoline-2,4(1H,3H)-dione was produced selectively with 92% yield at 120 °C, 4.2 MPa, and automatically separated from the hot catalytic aqueous solution, which was reused directly for several runs until its activity decreased in an obvious manner. Then, the catalyst melamine was recrystallized from the spent aqueous solution via simple cooling and reused for another several catalytic runs. The efficient valorization of CO2 and the straightforward stepwise recovery of the products and catalyst were important to save energy and minimize process waste for the practical industrial production.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-15T08:00:00Z
      DOI: 10.1139/cjc-2017-0705
       
  • Synthesis, optical characterization, and TD-DFT studies of novel
           mero/bis-mero cyanine dyes based on N-Bridgehead heterocycles
    • Authors: Ahmed I. Koraiem, Islam M. Abdellah, Ahmed El-Shafei, Fathy F. Abdel-Latif, Reda M. Abd El-Aal
      Pages: 219 - 226
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 219-226, March 2019.
      Novel mero/bis-mero cyanine dyes based on N-Bridgehead imidazo[1,2-g]quinolino[2,1-a][2,6]naphthyridine have been synthesized and characterized to evaluate intramolecular charge transfer (ICT) effect on the energy gap (E0-0). The UV–vis and emission spectral studies revealed that dyes are absorbed in the region of λmax 485–577 nm and emitted at 567–673 nm. Their solvatochromic behavior in solvents of various polarities, CCl4, C6H6, H2O, CHCl3, acetone, and DMF, was studied to emphasize the effect of solvent polarity on the absorption maxima, molar extinction coefficients of the dyes, and excitation energy of the dyes. Their electron cloud delocalization in HOMO/LUMO levels were studied by DFT using Gaussian 09 software. Time-dependent density functional theory (TD-DFT) was applied to theoretically explore the first excitation energy (E0-0) of these dyes, which was in good agreement with experimental results.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-15T08:00:00Z
      DOI: 10.1139/cjc-2018-0325
       
  • Effect of cobalt doping on microstructures and dielectric properties of
           ZnO
    • Authors: Ye Zhao, Fan Tong, Mao Hua Wang
      Pages: 227 - 232
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 227-232, March 2019.
      Pure and cobalt-doped ZnO nanoparticles (2.5, 5, 7.5, and 10 atom % Co) are synthesized by sol–gel method. The as-synthesized nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM) analysis. The nanoparticles of 0, 2.5, and 5 atom % Co-doped ZnO exhibited hexagonal wurtzite structure and have no other phases. Moreover, the (101) diffraction peaks position of Co-doped ZnO shift toward a smaller value of diffraction angle compared with pure ZnO powders. The results confirm that Co ions were well incorporated into ZnO crystal lattice. Simultaneously, Co doping also inhibited the growth of particles, and the crystallite size decreased from 43.11 nm to 36.63 nm with the increase in doping concentration from 0 to 10 atom %. The values of the optical band gap of all Co-doped ZnO nanoparticles gradually decreased from 3.09 eV to 2.66 eV with increasing Co content. Particular, the dielectric constant of all Co-doped ZnO ceramics gradually increased from 1.62 × 103 to 20.52 × 103, and the dielectric loss decreased from 2.36 to 1.28 when Co content increased from 0 to 10 atom %.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-16T08:00:00Z
      DOI: 10.1139/cjc-2018-0195
       
  • Colorimetric detection of cysteine based on dispersion–aggregation
           mechanism of chitosan stabilized gold nanoparticles
    • Authors: Esther Jeyasekaran, Sridevi Venkatachalam
      Pages: 233 - 237
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 233-237, March 2019.
      A simple and selective colorimetric method for detection of cysteine using chitosan stabilized gold nanoparticles has been developed. L-cysteine is a sulfur containing amino acid. Cysteine binds with the gold nanoparticles through a sulfur group and induces aggregation of the nanoparticles, which leads to a visible colour change from pale red to blue. A good linearity was observed from 0.1 to 30 μmol/L (R = 0.9958) cysteine, and the limit of detection was found to be 0.1 μmol/L. The gold nanoparticles showed a high selectivity towards the detection of cysteine even in the presence of 10 000 fold higher concentration of common interferences such as glutathione, methionine, and homocysteine. A plausible mechanism for the selective detection of cysteine in presence of interferences based on a dispersion–aggregation mechanism has been proposed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-22T08:00:00Z
      DOI: 10.1139/cjc-2018-0258
       
  • Platinum(II) complexes of pyridine–amine ligands with phenol
           substituents: isotactic supramolecular polymers
    • Authors: Mahmood A. Fard, Ava Behnia, Richard J. Puddephatt
      Pages: 238 - 243
      Abstract: Canadian Journal of Chemistry, Volume 97, Issue 3, Page 238-243, March 2019.
      The platinum(II) complexes [PtCl(SMe2)(κ2-N,N′-L)]Cl and [PtMe(SMe2)(κ2-N,N′-L)]Cl, L = 2-C5H4NCH2NH-x-C6H4OH (x = 2, 3, or 4), have been prepared and structurally characterized. In all cases, the complexes form supramolecular polymers in the solid state by NH··Cl and OH··Cl hydrogen bonding to the chloride anion. The ligands are chiral at the amine nitrogen atom, and in all cases, the polymers are isotactic, formed by self-recognition or narcissistic self-assembly. The structures in the crystalline state all have the Me2S ligand trans to pyridyl, but in solution, the methylplatinum(II) complexes isomerise slowly to give an equilibrium with the isomers having the methyl group trans to the pyridyl donor.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-22T08:00:00Z
      DOI: 10.1139/cjc-2018-0435
       
  • A spectroscopic study of a cyclodextrin-based polymer and the “molecular
           accordion” effect
    • Authors: Abdalla H. Karoyo, Lee D. Wilson
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The formation of host–guest complexes was studied for two hosts: β-cyclodextrin (β-CD) and a cross-linked polymer containing an equimolar ratio of β-CD and hexamethylene diisocyanate (HDI), denoted as HDI-1. The thermodynamics of host–guest binding were studied with 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS) using steady-state fluorescence spectroscopy in aqueous solution at variable temperature and ambient pH. The association of 1,8-ANS with β-CD and HDI-1 showed a fluorescence enhancement of ∼4 and 12 units, respectively. Greater fluorescence enhancement for the polymer/dye system indicates the presence of multiple binding sites (inclusion and interstitial). By contrast, the β-CD/dye system adopts trends that indicate the formation of well-defined inclusion complexes. HDI-1 has inclusion sites (β-CD) and interstitial domains (HDI) that afford dual binding with variable binding affinity. Simplified binding models employed herein address the role of inclusion binding without an explicit account for higher order or secondary binding equilibria. The approximate 1:1 binding constant (K1:1) for CD/1,8-ANS is about two-fold greater over the HDI-1/1,8-ANS system. HDI-1 displays cooperative effects among the polymer subunits, according to changes in relative fluorescence intensity due to structural transitions and binding site loci. The relative fluorescence intensities of the HDI-1/1,8-ANS system relate to a reversible temperature-driven structural transition (globular ⇌ extended) of the polymer between 5 °C and 60 °C, in contrast to the β-CD/1,8-ANS complex. The temperature- and guest-driven structural transition, described as the “molecular accordion” effect, is supported by new insight provided by complementary fluorescence and 1H NMR spectral results in aqueous solution.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-12-18T08:00:00Z
      DOI: 10.1139/cjc-2018-0420
       
  • Strong, near-infrared absorbing porphyrins: a DFT study
    • Authors: Neha Agnihotri
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A systematic density functional theory study of electronic properties and optical spectra of four potential fused porphyrins with extended π-conjugation has been reported employing the M06 functional along with 6-31G(d)+LanL2DZ basis set. Symmetrical tetra fusion of the benzene rings at the β-meso-β position of porphyrins, resulted in four quadruply fused porphyrins. Such studies revealed the fact that the ring fusion with extended π-electrons causes remarkable red-shifts with narrowed band gaps. Thus, such systems can be used to extend the absorption deeper in to near-infrared (NIR) to even better utilize the photon rich region of solar spectrum. These fused porphyrins have emerged as promising NIR absorbing materials, having utility in molecular solar-conversion systems.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-12-17T08:00:00Z
      DOI: 10.1139/cjc-2018-0416
       
  • Theoretical study on polyglycerine polynitrates for potential high-energy
           plasticizers of propellants
    • Authors: Guixiang Wang, Yimin Xu, Wenjing Zhang, Chuang Xue, Xuedong Gong
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Polyglycerine polynitrates such as nitroglycerine can be used as energetic plasticizers of propellants. In this study, 29 derivatives of nitroglycerine are investigated at the B3LYP/6-31G* level of the density functional theory. The corrected theoretical densities ([math]) are predicted and are found to be very close to the experimental values. Detonation properties are calculated using the modified Kamlet–Jacobs equations and the specific impulse (Is) is evaluated according to the maximum exothermic principle. A new parameter K, which is the product of Is and [math], is proposed to evaluate the overall energetic characteristics of compounds. Thermal stability is discussed by calculating the bond dissociation energies or bond dissociation energy barriers. The O–NO2 bond has the smallest bond dissociation energy and is the trigger bond for each of the studied compounds. The influence of the –ONO2 and –CH2–O–CH2–CH(ONO2)– groups, which is useful for design of new high energy plasticizers, is also discussed. Comprehensively considering the energetic properties and the stability, DGPN, DGHN, TriGHeptaN, TriGON, TriGNN, TetraGNN, TetraGDeN, TetraGUN, and TetraGDoN are possibly better energetic plasticizers of solid propellants than nitroglycerine.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-12-17T08:00:00Z
      DOI: 10.1139/cjc-2018-0466
       
  • Hydrophobic polythiophene hole-transport layers to address the
           moisture-induced decomposition problem of perovskite solar cells
    • Authors: Soumya Kundu, Timothy L. Kelly
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Perovskite solar cells have emerged as one of the most promising next-generation photovoltaic technologies and have achieved a record power conversion efficiency of 22.7%. The technology meets industrial demands for cost effectiveness and scalability; however, the instability of lead halide perovskites toward moisture is a major barrier to their commercial development. Previous studies have revealed that the use of hydrophobic hole-transport layers (e.g., poly(3-hexylthiophene), P3HT) can slow the ingress of water vapor and improve the lifetime of the underlying perovskite, suggesting a route to longer lived devices. In this work, we report the synthesis of a variety of poly(3-alkoxythiophenes) with different side chains. The side chains range from hydrophilic (triethylene glycol methyl ether) to extremely hydrophobic (highly fluorinated hexyloxy). We evaluated the polymers, alongside commercially available P3HT, for their ability to stabilize methylammonium lead iodide films at high relative humidities. The fluorinated polythiophenes were able to substantially improve the perovskite lifetime, suggesting that more hydrophobic hole-transport layers may be a route to more stable perovskite solar cells.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-12-04T08:00:00Z
      DOI: 10.1139/cjc-2018-0414
       
  • Systematic exploration of the pH dependence of a peptide hydrogel
    • Authors: Natashya Falcone, Tsuimy Shao, Xiaoyi Sun, Heinz-Bernhard Kraatz
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Stimuli-responsive peptide gels are a growing class of functional biomaterials that are involved in many applications in research. Here, we present a novel di-peptide hydrogel from the compound Boc–Phe–Trp–OH in various buffer and pH conditions. We examine the effects of different stimuli, including temperature and pH, on the mechanical strength of the gels through frequency rheology studies. We found that this hydrogelator is highly pH dependent, only forming a gel in a narrow range of pH 6–7. This hydrogelator hold promise for the development of new stimuli-responsive biomaterials for specific applications that require this type of specific stimuli.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-12-04T08:00:00Z
      DOI: 10.1139/cjc-2018-0419
       
  • Fluorescence anisotropy imaging of a polydiacetylene photopolymer film
    • Authors: Hamid Soleimaninejad, Kenneth P. Ghiggino, Trevor A. Smith, Matthew F. Paige
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      UV-illumination of phase-separated surfactant films prepared from mixtures of photopolymerizable 10,12-pentacosadiynoic acid and perfluorotetradecanoic acid results in the formation of fluorescent polydiacetylene fibers and aggregates. In this work, the orientation of polymer strands that comprise the resulting photopolymer structures has been probed using fluorescence anisotropy imaging in combination with defocused single-molecule fluorescence imaging. Imaging experiments indicate the presence of significant fiber-to-fiber heterogeneity, as well as anisotropy within each fiber (or aggregate), with both of these properties changing as a function of film preparation conditions. This anisotropy can be attributed to various alignments of the constituent polymer strands that comprise the larger fibers and aggregates. Intriguingly, when using defocused imaging, fiber images consisted of a series of discrete “doughnut” fluorescence emission patterns, which exhibited intermittent on–off blinking behavior; both of these properties are characteristic of individual emission transition dipoles (single molecules). Further, all of the individual emission transition dipoles had a uniform orientation with respect to the axis of the fiber, indicating a common orientation of discrete emitters in the larger polymer fiber. The implications of these results for future studies of the electronic properties of conjugated polymers in larger macroscopic systems are noted.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-29T08:00:00Z
      DOI: 10.1139/cjc-2018-0360
       
  • A three-step synthesis of estra-4,9-diene-3,17-dione
    • Authors: Xiao-Yan Ma, Kun Zhang, Yan Liu, Jiao Xu, Ying-Ying Yang, Jie Liu, Xinjun Hu
      Pages: 1 - 3
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Estra-4,9-diene-3,17-dione, an important pharmaceutical intermediate, was synthesized by a three-step sequence from δ-lactone 1 in 23.4% overall yield. Reaction of δ-lactone 1 and Grignard reagent 2 followed by treatment with Jones reagent resulted in precursor 4. The domino cyclization reaction of 4 with piperidinium acetate gave estra-4,9-diene-3,17-dione.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-29T08:00:00Z
      DOI: 10.1139/cjc-2018-0455
       
  • ATR–IR spectroelectrochemical studies of arsenic speciation at the
           ferrihydrite–solution interface
    • Authors: Jessica A. Sigrist, Ian J. Burgess
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The adsorption of arsenic on an amorphous iron oxy(hydroxides) (ferrihydrite) under reductive conditions is reported. The fabrication of an ATR–IR spectroelectrochemical cell that allows the vibrational characterization of arsenate and arsenite adsorbed on a thin film of ferrihydrite is described. The cell is shown to allow the application of reductive conditions through the introduction of a working electrode that is positioned adjacent to the mineral phase. ATR–IR spectra reveal that increasingly negative solution potentials (Eh) leads to the loss of adsorbed arsenate prior to the reductive dissolution of Fe(III) in the ferrihydrite. Under the experimental conditions, there is no evidence of reduction of arsenate to arsenite. Through the use of a miniaturized pH probe, the desorption of arsenate through electrochemical biasing is shown to arise solely from competitive adsorption from hydroxide ions produced by electrolysis of water. The results indicate that, within the time frame accessible in these measurements, only extreme reductive conditions are detrimental to arsenic sequestration in mine tailings facilities.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-28T08:00:00Z
      DOI: 10.1139/cjc-2018-0399
       
  • Microstructure and optical properties of Na-doped ZnO system, synthesized
           by the sol–gel method
    • Authors: Fan Tong, Ye Zhao, Mao-Hua Wang
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Pure and Na-doped ZnO (2 at.%, 5 at.%, and 10 at.%) films are synthesized by sol–gel method and annealed at 500 °C for 4 h. The as-synthesized nanoparticles are characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS). The samples exhibited hexagonal ZnO lattice structure and another Na2O2 phase was detected in the 5 at.% Na-doped ZnO sample. The calculated average crystalline size increases from 42.0 nm to 43.5 nm when Na content increased from 0 to 10 at.%. FESEM and TEM analysis identifies that the average size of the Na-doped ZnO nanoparticles lies in between 50 nm and they appear in spheroid-like or rod-like shaped particles. The transmittance of the sample was above 80% and the results of photocatalytic activity show that Na-doped ZnO nanoparticles exhibit higher photodegradation activity (about 91%) than pure ZnO nanoparticles under UV irradiation.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-27T08:00:00Z
      DOI: 10.1139/cjc-2018-0270
       
  • Pressure-induced metallization of condensed-phase RDX: molecular dynamic
           simulations in conjunction with MSST method
    • Authors: Zi-Qiu Bai, Jing Chang, Guang-Fu Ji, Ni-Na Ge
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The anisotropy of impact sensitivity and microscopic electron properties of the cyclotrimethylene trinitramine (C3H6N6O6) (RDX) under shock loading are investigated in our work. The simulation is performed using molecular dynamic (MD) simulations in conjunction with multi-scale shock technique (MSST). By calculating the microscopic electronic properties and combining the thermodynamic properties, we predict that the metallization pressure of the RDX crystal is approximately 170 GPa under shock loading, which is slightly less than the metallization pressure under hydrostatic pressure. We also found that the microscopic electronic properties are related to the impact sensitivity. When the shock loading is along the z direction, the time of the transition from the insulating state to the metallization of the RDX crystal lags behind the shock loading along the x or y direction. Therefore, we predict that the RDX crystal has a lower sensitivity when the shock loading is along the z direction.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-20T08:00:00Z
      DOI: 10.1139/cjc-2018-0256
       
  • Initial excited-state structural dynamics of 2′-deoxyadenosine
    • Authors: Swaroop Sasidharanpillai, Adam A. Friedman, Glen R. Loppnow
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Purine nucleobases (adenosine and guanosine) are prone to spontaneous breaking of the nucleosidic bond to form abasic sites in both DNA and RNA. However, the purines also undergo photochemical reactions, including oxidation and cycloaddition, to form damage sites, albeit at lower photochemical quantum yields than the pyrimidines. In this study, we use ultraviolet resonance Raman spectroscopy to measure the initial excited-state structural dynamics in the nucleoside, 2′-deoxyadenosine. The resonance Raman-derived initial excited-state structural dynamics throughout the 260 nm La excited electronic state of adenine are found to be smaller in the nucleoside than in the previously reported 9-methyladenine nucleobase derivative, consistent with what is found for the pyrimidines thymine and uracil. Interestingly, resonance-enhanced vibrational modes in this electronic state also contain internal coordinates localized on the sugar, which may represent a different energy dissipation mechanism than in the pyrimidine nucleosides. The results will be discussed in terms of the initial excited-state photophysics and photochemistry of DNA and RNA.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-07T08:00:00Z
      DOI: 10.1139/cjc-2018-0409
       
  • Synthesis of amphiphilic asymmetrical dithienylethenes with aryl groups at
           the reactive carbons
    • Authors: M.S. Jemeli Sang, Jianxin Cai, Yamuna S. Kandasamy, R. Scott Murphy
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A synthetic route for the preparation of amphiphilic asymmetrical dithienylethenes that incorporate methyl groups at the 4- and 4′-positions and an aryl group at one of the reactive carbons has been developed. The presence of a bulky aryl substituent ensures a relatively large change in molecular geometry upon photoisomerization, whereas the presence of methyl groups provide enhanced photostability. Notably, a substituent effect was systematically revealed en route to the preparation of the dithienylethene precursors. In particular, this formal substitution reaction was significantly inhibited due to steric hindrance, stemming from the presence of aryl and methyl groups at the alpha positions of the preformed thienyl carbanionic carbon, and an aryl group on the monosubstituted perfluorocyclopentene derivative.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-11-01T07:00:00Z
      DOI: 10.1139/cjc-2018-0422
       
 
 
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