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  Subjects -> CHEMISTRY (Total: 885 journals)
    - ANALYTICAL CHEMISTRY (55 journals)
    - CHEMISTRY (619 journals)
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CHEMISTRY (619 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: 27)
ACS Catalysis     Hybrid Journal   (Followers: 44)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 22)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 26)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 41)
ACS Nano     Hybrid Journal   (Followers: 295)
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: 5)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     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: 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: 6)
Advanced Functional Materials     Hybrid Journal   (Followers: 60)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 69)
Advances in Chemical Science     Open Access   (Followers: 18)
Advances in Chemistry     Open Access   (Followers: 22)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19)
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: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 26)
Advances in Nanoparticles     Open Access   (Followers: 15)
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: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 3)
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  
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: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 21)
American Journal of Chemistry     Open Access   (Followers: 31)
American Journal of Plant Physiology     Open Access   (Followers: 11)
American Mineralogist     Hybrid Journal   (Followers: 15)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 171)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 255)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 5)
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: 13)
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: 24)
Applied Surface Science     Hybrid Journal   (Followers: 32)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
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: 2)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Hybrid Journal   (Followers: 369)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 10)
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: 22)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 11)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 134)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 87)
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: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 10)
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: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 74)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 26)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 197)
Chemical Science     Open Access   (Followers: 26)
Chemical Technology     Open Access   (Followers: 28)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry & Industry     Hybrid Journal   (Followers: 7)
Chemistry - A European Journal     Hybrid Journal   (Followers: 159)
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: 44)
Chemistry of Materials     Hybrid Journal   (Followers: 266)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 20)
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: 4)
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: 24)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 6)
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: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access  
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: 12)
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: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 6)
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: 71)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 3)
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  

        1 2 3 4 | Last

Journal Cover
Canadian Journal of Chemistry
Journal Prestige (SJR): 0.29
Citation Impact (citeScore): 1
Number of Followers: 10  
  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]
  • Synthesis and characterization of novel bis(pyridine-2(1H)-thiones) and
           their bis(2-methylsulfanylpyridines) incorporating 2,6-dibromophenoxy
    • Authors: Sherif M.H. Sanad, Azza M. Abdel-Fattah, Fawzy A. Attaby, Mohamed A.A. Elneairy
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The novel 1,4-bis(2,6-dibromo-4-formylphenoxy)butane (3), prepared from 3,5-dibromobenzaldehyde (1), reacted with different hydrazines 4a–4d and active methylene containing compounds 9a–9d to give the corresponding bis(hydrazones) 5a–5d and bis(cinnamonitriles) 11a–11d, respectively. Both bis(2-cyanoacetic acid hydrazide) derivative 5d and bis(thioacrylamide) derivative 11a were taken as synthetic precursors for the synthesis of the target molecules bis(pyridine-2(1H)-thione) derivative 10 and 13a–13c and their bis(2-methylsulfanylpyridine) derivative 14 and 17a–17c. Another synthetic route was designed to prepare the target molecules 14 and 17a–17c in a better yield using pyridine-2(1H)-thione) derivative 15 and 19a–19c. Characterization of the newly prepared compounds via elemental analyses and spectral data are established.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-22T07:00:00Z
      DOI: 10.1139/cjc-2017-0721
  • Selectfluor-mediated oxidative methylenation of amide with
           N,N-dimethylpropanamide for N,N′-methylenebisamide synthesis
    • Authors: Yue Cao, Dongheng Zhou, Yongmin Ma
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A simple and efficient approach for the synthesis of N,N′-methylenebisamides through a Selectfluor-mediated oxidative reaction of aromatic amides and N,N-dimethylpropanamide (DMP) is described. Remarkable results clearly reveal that DMP plays a dual role in this reaction, as both a one-carbon source and an environment-friendly solvent. Moreover, the process provides new strategies for the synthesis of bisamides with advantages of operationally simple, insensitive to atmospheric conditions, and good to high yields.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-20T07:00:00Z
      DOI: 10.1139/cjc-2018-0181
  • Efficient reduction of formic acid to formaldehyde by zinc
    • Authors: Nicholas P. Alderman, Virginie Peneau, Camilo J. Viasus, Ilia Korobkov, Balamurugan Vidjayacoumar, Khalid Albahily, Sandro Gambarotta
      Pages: 1 - 4
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The possibility of thermally reducing formic acid to formaldehyde selectively has been probed using metallic zinc. Good selectivity (over 80%) was obtained with low concentrations of formic acid, with methanol and methyl formate as secondary products. The selectivity can be tuned by changing the carrier gas flow, temperature, and zinc amount. Zinc was oxidized to zinc oxide during this process.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-20T07:00:00Z
      DOI: 10.1139/cjc-2018-0284
  • Synthesis, characterization of active Sn(0), and its application in
           selective propargylation of aldehyde at room temperature in water
    • Authors: Paresh Nath Chatterjee, Dipankar Paul, Micky Lanster Sawkmie, Arun Kumar Sinha, Snehadrinarayan Khatua
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Active Sn(0) particles are synthesized in high yields by the chemical reduction of the blue–black stannous oxide using freshly prepared sodium stannite solution as reducing agent at 40 °C and 60 °C. The Sn(0) particles are characterized using powder XRD, SEM, and DSC. The as-synthesized Sn(0) particles are applied as reagent for the regioselective synthesis of homopropargyl alcohols from propargyl bromide and aldehydes in distilled water at room temperature (in 50%–84% yields). No assistance of heat, microwave, ultrasound, organic co-solvent, co-reagent, or inert atmosphere is required for this reaction. The propargylation reaction is highly chemoselective towards aldehyde over other less electrophilic carbonyl functional groups such as ketone, amide, and carboxylic acid. Our in-house synthesized homopropargyl alcohols can be used to synthesize conjugated 1,3-diynes.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-18T07:00:00Z
      DOI: 10.1139/cjc-2017-0745
  • Isolation of RNA from a mixture and its detection by utilizing a
           microgel-based optical device
    • Authors: Molla R. Islam, Shakiba Azimi, Faranak Teimoory, Glen Loppnow, Michael J. Serpe
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      In this investigation, we show that RNA can be separated from a solution containing DNA and RNA and the isolated RNA can be detected using poly (N-isopropylacrylamide-co-N-(3-aminopropyl) methacrylamide hydrochloride) microgel-based optical devices (etalons). The isolation of RNA was accomplished by using hairpin-functionalized magnetic beads (MMPDNA) and differential melting, based on the fact that the DNA–RNA hybrid duplex is stronger (i.e., high melting temperature) than the DNA–DNA duplex (i.e., low melting temperature). By performing concurrent etalon sensing and fluorescent studies, we found that the MMPDNA combined with differential melting was capable of selectively separating RNA from DNA. This selective separation and simple colorimetric detection of RNA from a mixture will help lead to future RNA-based disease diagnostic devices.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-12T05:55:46Z
      DOI: 10.1139/cjc-2018-0199
  • Facile direct synthesis of amides from trichloroethyl esters using
           catalytic DBU
    • Authors: Minh Thanh La, Hee-Kwon Kim
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A practical method for the direct synthesis of amide compounds is described. Using small quantities of DBU as a catalyst, the direct conversion of 2,2,2-trichloroethyl esters to their corresponding amides was readily achieved. Based on this protocol, various amide compounds were successfully synthesized in high yield, suggesting a promising approach for the practical one-pot aminolysis from 2,2,2-trichloroethyl protected esters.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-07T07:00:00Z
      DOI: 10.1139/cjc-2018-0234
  • Synthesis and vasodilator activity of 3,4-dihydropyrimidin-2(1H)-ones
           bearing urea, thiourea, and sulfonylurea moieties
    • Authors: Tahir Habila, Mebrouk Belghobsi, Mohamed-Zakaria Stiti, Eric Goffin, Pascal de Tullio, Gilles Faury, Bernard Pirotte, Smail Khelili
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A series of novel 3,4-dihydropyrimidin-2(1H)-ones bearing urea, thiourea, and sulfonylurea moieties were synthesized and pharmacologically evaluated as vasodilator agents. The most interesting vasodilators were the thiourea derivatives 6a and 6b and the urea derivatives 6f–6i and 7f–7h, although the ureas were relatively more active than thioureas. Twenty-fold more active than diazoxide, the urea 6g was the most potent vasodilator (EC50 = 0.983 ± 0.061 μmol/L) and proved to act as a voltage-gated calcium channel blocker. The lack of activity of sulfonylureas, 6k and 7j, could be attributed to their partial ionization at the physiological pH because of their acidic character. It should be interesting to investigate a larger number of compounds, including N-methylated sulfonylureas, to increase the vasodilator activity and to explore other biological models.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-09-07T07:00:00Z
      DOI: 10.1139/cjc-2018-0239
  • Hydrazinolysis of aryl cinnamates and related esters: the α-effect arises
           from stabilization of five-membered cyclic transition state
    • Authors: Ik-Hwan Um, Ae-Ri Bae, Julian M. Dust
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A kinetic study is reported for nucleophilic substitution reactions of Y-substituted-phenyl cinnamates (1a–1h) with a series of primary amines including hydrazine in H2O containing 20 mol % DMSO at 25.0 °C. The Brønsted-type plot for the reaction of 2,4-dinitrophenyl cinnamate (1a) is linear with βnuc = 0.57 except hydrazine, which exhibits positive deviation from the linear correlation (i.e., the α-effect). The Brønsted-type plots for the reactions of 1a–1h with hydrazine and glycylglycine (glygly) are also linear with βlg = –0.71 and –0.87, respectively, when 1a is excluded from the linear correlation. Thus, the reactions have been concluded to proceed through a concerted mechanism on the basis of the linear Brønsted-type plots and magnitudes of the βnuc and βlg values. The α-effect shown by hydrazine is dependent on electronic nature of the substituent Y in the leaving group, e.g., it increases as the substituent Y becomes a weaker electron-withdrawing group (or as basicity of the leaving aryloxide increases), indicating that the α-effect is not due to destabilization of the ground state but mainly due to stabilization of the transition state. A five-membered cyclic TS structure, which could increase nucleofugality of the leaving aryloxide through H-bonding interaction, has been proposed to account for the leaving-group dependent α-effect found in this study. The theories suggested previously to rationalize the α-effect found for the related systems are also discussed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-29T07:00:00Z
      DOI: 10.1139/cjc-2018-0290
  • Kinetic study on aminolysis of aryl X-substituted-cinnamates in
           acetonitrile: differential medium effect determines reactivity and
           reaction mechanism
    • Authors: Ik-Hwan Um, Ae-Ri Bae, Julian M. Dust
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A kinetic study on nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted-cinnamates (1a–1f) and Y-substituted-phenyl cinnamates (2a–2g) with a series of alicyclic secondary amines in MeCN at 25.0 ± 0.1 °C is reported. The Brønsted-type plots for the reactions of 1a–1f are linear with βnuc = 0.47∼0.50, indicating that the bond formation between the amine nucleophile and the electrophilic center is advanced slightly in the transition state. The Brønsted-type plot for the reactions of 2a–2g with piperidine is also linear with βlg = –0.66, which is a typical βlg value for reactions reported previously to proceed through a concerted mechanism. Furthermore, the Hammett plot correlated with σ– constants results in much better linearity than that correlated with σo constants, implying that expulsion of the leaving group is advanced in the rate-determining step (RDS). Thus, the reactions are concluded to proceed through a concerted mechanism. The Hammett plots for the reactions of 1a–1f consist of two intersecting straight lines, whereas the corresponding Yukawa–Tsuno plots exhibit excellent linear correlations with ρX = 0.62∼0.71 and r = 0.65∼0.68. Apparently, the nonlinear Hammett plots are not due to a change in the reaction mechanism (or the RDS) but are caused by stabilization of the substrate possessing an electron-donating group (EDG) in the cinnamoyl moiety through resonance interactions between the EDG and the C=O bond of the substrate. Medium effects on reactivity and reaction mechanism are also discussed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-29T07:00:00Z
      DOI: 10.1139/cjc-2018-0310
  • Phenanthridine-based nitrones as substrates for strain-promoted
           alkyne-nitrone cycloadditions
    • Authors: Miroslava Strmiskova, Didier A. Bilodeau, Mariya Chigrinova, John Paul Pezacki
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Over the past decade, bioorthogonal chemistry that facilitates the efficient conjugation of biomolecules has expanded from the copper-catalyzed alkyne-azide cycloadditions to a multitude of diverse reactions, varying additives and reactional partners, and most often offering better alternatives with faster rates and lower toxicity of employed reactants. Among these, the copper-free strain-promoted cycloaddition reactions have been demonstrated to be more promising, offering a reaction without toxic metal catalysts and with faster inherent kinetic rate constants. The strain-promoted alkyne-nitrone cycloadditions are easily tunable from both the (strained) alkyne and nitrone perspective, both compounds giving the opportunity to modulate the rate of reaction by substituting various positions. Previously, acyclic nitrones have been evaluated in the strain-promoted alkyne-nitrone reactions; however, they were notably prone to hydrolysis. Some five-membered ring endocyclic nitrones developed concomitantly offered the advantage of relatively fast kinetics and better resistance to degradation in aqueous conditions and have been successfully used for labelling of biomolecules in living systems. Herein, we have prepared and studied nitrones inspired by the phenanthridine scaffold that efficiently undergo strain-promoted alkyne-nitrone reactions. Phenanthridine nitrones react fast with strained cyclooctynes with large bimolecular rate constants while maintaining bioorthogonality and resistance to hydrolysis.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-29T07:00:00Z
      DOI: 10.1139/cjc-2018-0253
  • Enhanced light absorption in simulations of ultra-thin ZnO layers
           structured by a SiO2 photonic glass
    • Authors: Robert H. Coridan, Mya A. Norman, Hamed Mehrabi
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Hierarchically organized nanostructures are often employed to improve the energy conversion efficiency of photovoltaic and photoelectrochemical cells. Ultra-thin semiconductors can improve the internal carrier collection yield in materials with poor carrier lifetimes by reducing the characteristic length scales of collection. However, reducing the dimension of the light absorber requires strategies to increase absorption and the overall photogeneration when the material is to be used in broadband solar energy conversion applications. Here, we explore a strategy for improving light absorption in nanometer-scale, ultra-thin film ZnO layers by integrating them into a SiO2 colloidal crystal-based photonic glass. We use three-dimensional finite-difference electromagnetic simulations to study the local and total absorption improvements on composite films of close-packed, randomized colloidal structures coated with a thin layer of ZnO. These simulations show that the near band-gap absorption in the ZnO coating is dependent on the degree of vacancies in the colloidal crystal that templates the photonic glass. With these results, we show that disordered, defective colloidal composites can potentially be used to fabricate nanostructured photoelectrodes based on ultra-thin semiconductor layers with improved light absorption characteristics.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-27T07:00:00Z
      DOI: 10.1139/cjc-2018-0218
  • A novel rhodamine-based fluorescent probe for selective detection of
           ClO– and its application in living cell imaging
    • Authors: Changping Yang, Mingliang Zuo, Xiaoli Hu, Xuelin Chen, Duoduo Zhang, Zhenping Qi, Xiaoyan Zhao, Hua Zuo
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A novel fluorescent rhodamine-based probe L for selective responding to ClO– has been synthesized and characterized. The spectroscopy showed that probe L can detect ClO– in aqueous solution without interaction with other interfering ions, and the detection is also evident by the colour change from colourless to reddish purple under white light. The remarkable fluorescence enhancement showed the high selectivity and sensitivity of probe L for the detection of ClO–. Furthermore, probe L was applied to intracellular fluorescent imaging of HeLa cells treated with ClO– and MTT assay showed nontoxicity in living cells.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-24T07:00:00Z
      DOI: 10.1139/cjc-2018-0123
  • Synthesis, characterization, and anticancer evaluation of some new
           N1-(anthraquinon-2-yl) amidrazone derivatives
    • Authors: Kamal Sweidan, Hiba Zalloum, Dima A. Sabbah, Ghada Idris, Khadija Abudosh, Mohammad S. Mubarak
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A new series of novel N1-anthraquinon-2-yl amidrazones incorporating N-piperazines and related congeners were synthesized via reaction of the hydrazonoyl chloride derived from 2-qaminoanthraquinone with the appropriate piperazine (secondary amine). Structures of the new compounds were confirmed by a panel of spectroscopic methods including IR, NMR, and MS and by elemental analysis. The antitumor activity of the newly prepared compounds was evaluated in vitro against MCF-7 breast cancer, K562 chronic myelogenous leukemia, and dermal fibroblasts cell lines by means of a cell viability assay using the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Results revealed that compounds 13a and 13d exhibit the highest inhibitory activity against K562 and MCF-7 cell lines. These two compounds could be considered as promising as potential anticancer drugs.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-20T07:00:00Z
      DOI: 10.1139/cjc-2018-0145
  • Ruthenium-catalyzed Bis-Homo-Diels-Alder reaction: searching for
           commercially available catalysts and expanding the scope of reaction
    • Authors: Dina Petko, Matthew Stratton, William Tam
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Commercially available ruthenium catalyst, Cp*RuCl(COD), was found to be active in catalyzing Bis-Homo-Diels-Alder [2+2+2] cycloaddition reactions between 1,5-cyclooctadiene and various alkynes giving moderate to good yields (35%–92%). The presence of electron donating groups, especially hydroxyl groups, greatly enhanced the reactivity of the alkyne moiety in the cycloaddition. The reaction was also found to be successful even in the presence of bulky substituents on the alkynes.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-20T07:00:00Z
      DOI: 10.1139/cjc-2018-0117
  • Synthesis and photophysical evaluation of new fluorescent
           7-arylethynyl-7-deazaadenosine analogs
    • Authors: Augusto Matarazzo, Justin Brow, Robert H.E. Hudson
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Three new fluorescent 7-deaza-2′-deoxyadenosine analogs were synthesized via the Sonogashira cross-coupling reaction of 7-iodo-7-deaza-2′-deoxyadenosine with 1-ethynylpyrene, 2-ethynyl-6-methoxynaphthalene, and 9-ethynylphenanthrene. The spectral properties of these analogs were evaluated in dioxane, EtOH, and H2O to determine their potential for use as environmentally sensitive fluorescent probes. All three analogs displayed large solvatofluorochromicity in H2O, relative to their emission wavelengths in dioxane or EtOH. Moreover, all three analogs exhibited microenvironmental sensitivity of their fluorescence emission intensity, being moderate to high quantum yields in dioxane and EtOH and significantly lower in H2O. Various attempts to perform domino cross-coupling and annuation reactions on 7-deaza-7-alkynyladenine derivatives to form a new fused tricyclic adenine analog were unsuccessful.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-17T07:00:00Z
      DOI: 10.1139/cjc-2018-0303
  • Preparation, characterization, and application of synthesized thiourea
           formaldehyde-calcium alginate in removal of Reactive Black 5
    • Authors: A.A. El-Bindary, A.F. Shoair, H.A. Kiwaan, A.R. Hawas
      Pages: 1 - 14
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Thiourea formaldehyde calcium alginate (TFCA) composite was successfully synthesized and used for removal of Reactive Black 5 (RB5) dye. The synthesized composite was applied and characterized by Fourier transform infrared spectrometer (FTIR) spectra, scanning electron microscope (SEM)/EDS, energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD). SEM and EDX analyses confirm the homogeneity of the sorbent in term of composition. Batch adsorption experiments were performed to evaluate the adsorption conditions such as pH value, dye concentration, contact time, temperature, and sorbent dose, as well as the ionic strength effect. Experimental data have been modeled by using Langmuir, Freundlich, Dubinin Radushkevich (D–R), and Temkin isotherms. Kinetic adsorption data modeled using PFORE, PSORE, Morris Weber, and Elovich in order to determine thermodynamic parameters (ΔG, ΔH, and ΔS) for the dye adsorbent systems. These data indicated an exothermic spontaneous adsorption process that kinetically followed the pseudo second-order adsorption process and removal of RB5 dye from aqueous solution. The results showed that the maximum adsorption capacity was 0.2 mmol g−1, observed at pH 1 and temperature 25 °C. Equilibrium adsorption was achieved within 60 min.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-15T07:00:00Z
      DOI: 10.1139/cjc-2017-0767
  • Green halogenation reactions for (hetero)aromatic ring systems in alcohol,
           water, or no solvent
    • Authors: Jessie K. Kajorinne, Jennifer C.M. Steers, Marnie E. Merchant, Craig D. MacKinnon
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A new method of brominating aromatic and heteroaromatic ring systems is investigated. The combination of hydrobromic acid as the halogen source, hydrogen peroxide as the oxidant, and ethanol, water, or no solvent are evaluated as greener conditions than those that have been previously published. The new conditions give high yields and good regioselectivity for a variety of substrates when the ring is activated by electron-donating groups or heteroatoms. Phenols, anisole, thiophenes, and pyrrole give comparable or superior results when compared to a traditional bromination by N-bromosuccinimide in tetrahydrofuran. Other nitrogen-containing heterocycles do not react under the conditions because they are protonated and hence deactivated; similarly, substrates with electron-withdrawing groups are not brominated. The reaction is very tolerant of a variety of functional groups.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-15T07:00:00Z
      DOI: 10.1139/cjc-2018-0259
  • A perspective on the magnetism of alkanethiol-coated gold thin films
    • Authors: Pengcheng Dong, Simon Trudel
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Intriguing ferromagnetic behaviour has been reported in gold thin films — a diamagnetic material in the bulk — wherein large magnetic moments and uncommon anisotropy are often hallmark features. The tuning of the electronic and magnetic properties by the presence of molecular self-assembled monolayers has been proposed. In this work, we present the study of the magnetism of a wide collection of alkanethiols of differing chain lengths coated on Au. We find no or only very weak magnetism, casting doubt on the universality and reproducibility of this phenomenon.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-08-12T07:00:00Z
      DOI: 10.1139/cjc-2018-0233
  • Synthesis of novel N-functionalized
           4-aryl-tetrahydrobiquinoline-2,5-(1H,3H)-diones via one-pot
           three-component reaction: a joint experimental and computational study
    • Authors: Vahideh Zadsirjan, Sayyed Jalil Mahdizadeh, Majid M. Heravi, Masumeh Heydari
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A novel series of N-functionalized 4-aryl-tetrahydrobiquinoline-2,5-(1H,3H)-diones were synthesized in high yields by a one-pot three-component reaction involving 2-chloroquinoline-3-carbaldehydes, Meldrum’s acid, and enaminones (dimedone-based enaminones) in the presence of K2CO3 in CH3CN under reflux condition. To gain a deep insight on the mechanism of the reaction, an extensive series of quantum mechanics calculations in the framework of density functional theory (DFT) were carried out for supporting the suggested reaction pathway.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-31T07:00:00Z
      DOI: 10.1139/cjc-2017-0564
  • New bis 1,3,4-oxadiazole derivatives: syntheses, characterizations,
           computational studies, and antioxidant activities
    • Authors: Yasemin Ünver, Halil Gökce, Ersan Bektaş, Fatih Çelik, İsmail Değirmencioğlu
      Pages: 1 - 13
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      In this study, two new bis oxadiazole derivatives (2a and 2b) were synthesized. The new compounds were characterized by elemental analyses, IR, 1H NMR, 13C NMR, and mass spectral studies and were tested for their antioxidant activity. According to the results, it was observed that the synthesized compounds (2a and 2b) had a very high activity in both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing ability of plasma (FRAP) tests. The approximate geometries of the compounds 2a and 2b were prepared with GaussView5 visualization program. The optimized molecular geometric parameters, vibrational wavenumbers, UV–vis parameters, and HOMO–LUMO simulations were computed using Gaussian 09W program. The computations were performed at 6-311++G(d,p) basis set using the B3LYP functional in density functional theory (DFT) method. The harmonic vibrational wavenumbers computed in gas phase were scaled with 0.958 (1700–4000 cm−1) and 0.983 (0–1700 cm−1) for the B3LYP/6-311++G(d,p) level. To calculated the UV–vis spectroscopic parameters with TD-DFT method, the compounds 2a and 2b were optimized in DMF and DMSO solvents using the integral equation formalism polarizable continuum model (IEFPCM) method at the B3LYP/6-311++G(d,p) level. The HOMO, LUMO, and UV–vis analyses were studied to interpret intramolecular charge transfers.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-30T07:00:00Z
      DOI: 10.1139/cjc-2018-0101
  • Preliminary investigations into the synthesis and antimicrobial activities
           of boron-containing capsaicinoids
    • Authors: Sharwatie Ramsaywack, Allyson Bos, Christopher M. Vogels, Christopher A. Gray, Stephen A. Westcott
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      This preliminary study reports on the synthesis of two new boron-capsaicin derivatives containing either a short or long chain aliphatic tail group using an iridium catalyzed hydroboration reaction with pinacolborane. The boronate ester groups reside on the terminal position of the tail group and are necessary for the bioactivity of these compounds. Indeed, both compounds showed considerable activity against two Gram-positive bacteria, including Vancomycin-resistant Enterococcus. Vancomycin is considered the last resort medication for the treatment of septicemia, and new antibacterial agents that can treat sepsis are of paramount importance. The more lipophilic boron compound with the longer aliphatic chain also showed antifungal activity against Saccharomyces cerevisiae.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-30T07:00:00Z
      DOI: 10.1139/cjc-2018-0193
  • A concise asymmetric synthesis of (−)-trans-aerangis lactone
    • Authors: Rachana Pandey, Ranjana Prakash
      Pages: 1 - 3
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A concise stereoselective approach to functionalized δ-lactone skeleton from monosilylated ethylene glycol as a starting material and its application to the asymmetric total synthesis of (−)-trans-aerangis lactone have been demonstrated. The synthesis utilizes the organocatalyzed MacMillan’s cross aldol reaction as a key step.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-30T07:00:00Z
      DOI: 10.1139/cjc-2018-0203
  • Two novel colorimetric probes (5-HMBA-FH and 3-HMBA-FH) based on
           fluorescein for copper(II) ion detection
    • Authors: Guanhong Liu, Peipei Ren, Fan Yang, Xuekai Dou, Jun Wang, Youtao Song
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Two novel isomeric colorimetric probes are established for simultaneous determination of copper ions using 2-hydroxy-5-methoxybenzaldehyde fluorescein hydrazone (5-HMBA-FH) and 2-hydroxy-3-methoxybenzaldehyde fluorescein hydrazone (3-HMBA-FH). They are synthesized by reacting fluorescein hydrazide with 2-hydroxy-5-methoxybenzaldehyde and 2-hydroxy-3-methoxybenzaldehyde, respectively, and then characterized by 1H-NMR, 13C-NMR, and infrared spectrum. The addition of copper ions to the solutions of two novel colorimetric probes can generate the obviously peaks at 498 nm in UV–vis absorption spectra along with a rapid colour change from colourless to dark yellow. The detection limits of the method for Cu2+ ion were 3.442 × 10−6 mol/L and 3.682 × 10−6 mol/L separately for 5-HMBA-FH and 3-HMBA-FH, respectively. The additions of other metal ions hardly affect the determination of copper ions. The proposed method was successfully applied to the analysis of Cu2+ ions in various samples. This method possesses high sensitivity, high simplicity, and minimized interference and will provide a great advantage in detecting copper ions in the environment, food, and medical applications.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-13T07:00:00Z
      DOI: 10.1139/cjc-2018-0105
  • A novel copper selective sensor based on ion imprinted 2-vinylpyridine
    • Authors: Murat Yolcu, Nurşen Dere
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A novel potentiometric Cu2+-selective microsensor has been developed that is based upon ion imprinted 2-vinylpyridine polymer. The polymer was synthesized using Cu(II) ions, 2-vinylpyridine, methacrylic acid, and ethylene glycol dimethacrylate as a template, functional monomer, and cross-linker, respectively. The resultant polymer was used as ionophore to obtain a selective potentiometric response towards Cu(II) ions in the structure of the PVC membrane. The detection limit of the microsensor was determined to be 8.4 × 10−7 mol/L, and its response time was considerably short (less than 15 s). The prepared microsensor exhibited a near-Nernstian response for Cu(II) ions over the concentration range of 10−1 to 10−6 mol/L, with a slope of 28.5 mV per decade over 2 months, and without any considerable divergence in potentials. The microsensor was effectively performed in a pH range between 4.0 and 7.0 and used as an indicator electrode in the potentiometric titration of Cu(II) ions with EDTA. The proposed microsensor has been successfully demonstrated for the determination of copper in a number of environmental water samples. The obtained potentiometric results were in good harmony with the results obtained by the AAS method.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-11T07:00:00Z
      DOI: 10.1139/cjc-2018-0178
  • Nebivolol nanoparticles: a first catalytic use in Biginelli and
           Biginelli-like reactions
    • Authors: Anamika Khaskel, Pranjit Barman, Subir Kumar Maiti, Utpal Jana
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Herein, we report the catalytic activity of nebivolol nanoparticles a novel organocatalyst for the synthesis of DHPMs and DHPM-5-carboxamides. The nanoparticles are confirmed by DSC, TEM, AFM, and IR spectroscopy. The catalyst can be readily recovered and reused for the next four runs without any significant impact on the yields of the products. The products are fully characterized by FTIR, 1H NMR, 13C NMR, and distortionless enhanced polarization transfer (DEPT) NMR. The methodology adopted here offers several advantages such as solvent-free reaction, low loading of catalyst, short reaction times, and quantifiable yields.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-05T07:00:00Z
      DOI: 10.1139/cjc-2017-0621
  • Unexpected medium effect on the mechanism for aminolysis of aryl phenyl
           carbonates in acetonitrile and H2O: transition-state structure in the
           catalytic pathway
    • Authors: Ik-Hwan Um, Ji-Hyun Song, Ae-Ri Bae, Julian M. Dust
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Upward curvature in the kinetic plots of pseudo first-order rate constants (kobsd) vs. [amine] for the aminolysis of aryl phenyl carbonates (5a–5j) in MeCN demonstrates that these reactions proceed via a zwitterionic tetrahedral intermediate (T±) that partitions between catalyzed and uncatalyzed routes to give the products. Yukawa–Tsuno plots for the reactions of 5a–5j with piperidine result in excellent linear correlations with ρY = 4.82 and r = 0.47 for the uncatalyzed reaction versus ρY = 2.21 and r = 0.21 for the catalyzed reaction. Brønsted plots for reactions of 4-(ethoxycarbonyl)-phenyl phenyl carbonate (5f) with a series of cyclic secondary amines exhibit excellent linear correlations with βnuc = 0.87 and 0.58 for the uncatalyzed and catalyzed reactions, respectively. The ΔH‡ and ΔS‡ values are 0.92 kcal/mol and –50.1 cal/mol K, respectively, for the catalyzed reaction of 5f with piperidine. Deuterium kinetic isotope effects found for reactions of 5f with piperidine/deuterated piperidine are 0.84 (uncatalyzed) and 1.42 (catalyzed). Multi-parameter analysis supports a concerted catalytic pathway involving a six-membered cyclic transition state rather than a traditionally accepted stepwise pathway with an anionic intermediate. The current unexpected results, where T± is the essential central intermediate in this aminolysis, contrast with previous calculation studies that deemed T± unstable in gas phase or MeCN.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-07-05T07:00:00Z
      DOI: 10.1139/cjc-2018-0204
  • Synthesis and self-assembly of thiol-modified tellurophenes
    • Authors: Gabrielle C. Hoover, Jennifer Ham, Connie Tang, Elisa I. Carrera, Dwight S. Seferos
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      An asymmetric thiol-modified tellurophene was designed and synthesized, and the ability of the compound to form a monolayer on a gold electrode was confirmed. The surface-active tellurophene was synthesized using Cadiot–Chodkiewicz coupling followed by ring closing and thiol modification. The tellurophene compound forms a monolayer on gold surfaces from a concentrated solution within 24 h. The ability of the compound to conjugate to gold is confirmed by X-ray photoelectron spectroscopy (XPS). A surface blocking experiment was used to evaluate the extent of formation of a monolayer on a gold electrode.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-29T10:46:00Z
      DOI: 10.1139/cjc-2018-0077
  • Theoretical study on the acidities of pyrrole, indole, carbazole and their
           hydrocarbon analogues in DMSO
    • Authors: Berkane Ariche, Ali Rahmouni
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      SMD and IEF-PCM continuum solvation models have been used, in combination with three quantum chemistry methods (B3LYP, M062X, and CBS-QB3), to study the acidities of pyrrole, indole, and carbazole, as well as their hydrocarbon analogues in DMSO, following a direct thermodynamic method. Theoretical parameters such as aromaticity indices (HOMA and SA), molecular electrostatic potential (MEP), and atomic charges have been calculated using B3LYP/6-311++G(d,p) level of theory. Calculated pKa values indicate that there is generally good agreement with experimental data, with all deviations being less than the acceptable error for directly calculated pKa values. The M062X functional combined with the SMD solvation model provided the most accurate pKa values. The MEP surfaces clearly show the electron density change accompanying the deprotonation process and explain the relative stability of conjugate bases. The HOMA aromaticity indices seem to be directly related to acidity strength. The collected data have been used to elucidate the pKa trends for the series of molecules under consideration.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-23T07:00:00Z
      DOI: 10.1139/cjc-2018-0032
  • Density functional study of guanidine-azole salts as energetic materials
    • Authors: Si-Yu Xu, Zhou-Yu Meng, Feng-Qi Zhao, Xue-Hai Ju
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A series of guanidine cations and azole anions were designed for use as energetic salts. Their geometrical structures were optimized by the density functional theory (DFT) method. The counter ions were matched by the similar magnitude of the electron affinity (EA) of the cation and the ionization potential (IP) of the anion. The densities, heats of formation, detonation parameters, and impact sensitivity were predicted. The incorporation of guanidine cations and diazole anions are favorable to form thermal stable salts except cation A1. The diaminoguanidine cation has greater impact on the density and detonation properties of the salts than the triaminoguanidine cation. 2-Amino-3-nitroamino-4,5-nitro-dinitropyrazole is the best anion for advancing the detonation performance among all the anions. Incorporating the C=O bond into the guanidine cations enhances the density and detonation performance of the guanidine-azole salts. The salts containing III1–III4 anion have better detonation properties than HMX, indicating that these salts are potential energetic compounds. Compared with RDX or HMX, some salts with diaminoguanidine cation display lower impact sensitivity.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-14T07:00:00Z
      DOI: 10.1139/cjc-2018-0106
  • Adsorption mechanism of CO molecule on Al(111) surface: periodic DFT
    • Authors: Chenhong Xu, Suqin Zhou, Jing Chen, Yuxiang Wang, Lei He
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The adsorption mechanism of the CO molecule on Al(111) surface has been investigated systematically at the atom-molecule level by the method of periodic density functional theory. The adsorption energies, adsorption structures, charge transfer, and density of states have been calculated in a wide range of coverage. It is found that the hcp-hollow site is the energetically favorable site. A significant positive correlation has been found between the adsorption energy (Eads) and coverage. The adsorbed CO molecules are almost perpendicular on the surface with the C atom facing the surface. There is an obvious charge transfer from Al atoms to the C atom; the Al atoms that have interaction with the C atom offer the most charge. The 4σ, 1π, and 5σ molecular orbitals of CO are found to contribute to bonding with the Al. The charges filling in the 2π molecular orbital contribute to C–O bond activation. In conclusion, the passivation of aluminum surface and the activation of CO molecule occur simultaneously in the adsorption of CO on Al surface.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-14T07:00:00Z
      DOI: 10.1139/cjc-2018-0169
  • Novel N-chloramine precursors for antimicrobial application: synthesis and
           facile covalent immobilization on polyurethane surface based on
           perfluorophenyl azide (PFPA) chemistry
    • Authors: Lingdong Li, Fengxiang Zhang, Fangyuan Gai, Hao Zhou, Xiaofang Chi, Hande Wang, Zongbao Zhao (Kent)
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      To control the pathogen cross contaminations on medical material surface, there is a pressing need to develop antimicrobial materials with highly efficacious surface biocidal activity. In this work, N-chloramine precursors containing a quaternary ammonium unit and perfluorophenyl azide unit were synthesized and covalently immobilized on inert polyurethane (PU) film upon UV light irradiation. The surface modification was confirmed by contact angle, Fourier transform infrared (ATR FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) analyses. After bleaching treatment, satisfactory biocidal activity was achieved for the surface-modified PU films. It was found that the introduced surface QA center contributed an even faster surface contact killing behavior and that precursors with a longer structural linker caused higher surface chlorine content and higher antimicrobial efficacy. This approach provides a novel and facile method that enables the covalent immobilization of N-chloramine precursors on inert polymeric surface to produce durable antimicrobial materials.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-12T07:00:00Z
      DOI: 10.1139/cjc-2018-0156
  • Computational study of polarizability anisotropies
    • Authors: Delano P. Chong
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The dipole polarizabilities (α) and polarizability anisotropies (Δα) of over 20 molecules are calculated to search for negative Δα. The geometry of each molecule is first optimized at the level of CCSD(T)/cc-pVQZ. Then, the α tensors are computed both with CCSD(T)/daug-cc-pVTZ in Gaussian 09 and with the exchange-correlation potential Vxc known as SAOP in the Amsterdam density functional theory program called ADF and a large basis set called QZ3P-3DIFFUSE. In addition to the popular formula of the ΔαRaman connected with Raman spectroscopy, we also present values of an alternative definition of the polarizability anisotropy ΔαKerr connected with Kerr spectroscopy, recently proposed by Kampfrath and colleagues (2018. Chem. Phys. Lett. 692: 319). On one hand, the signs of many ΔαRaman are undetermined; on the other hand, we obtain negative ΔαKerr for more than one-half of the small molecules studied. Of the 24 molecules studied, 18 have negative ΔαKerr.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-08T07:00:00Z
      DOI: 10.1139/cjc-2018-0171
  • Systematic evaluation of inorganic salts as a heat sink for the
           magnesiothermic reduction of silica
    • Authors: Logesh Khanna, Yiqi Lai, Mita Dasog
      Pages: 1 - 4
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      In this study, the effectivity of a series of inorganic salts, sodium chloride, calcium chloride, magnesium chloride, potassium chloride, and sodium bromide as heat sinks during magnesiothermic reduction of silica to porous silicon was investigated. The salts were chosen based on cost, thermal stability, ability to remain chemically inert during the reduction process, and ease of removal after the reaction. The structural integrity of the spherical porous silicon nanoparticles was observed using scanning electron microscopy, the surface area was determined via nitrogen adsorption experiments, and the crystallite size was determined using powder X-ray diffraction analysis; together, these were used to determine the efficacy of each salt. The ability of a salt to act as an effective heat sink was found to be highly correlated and principally dependent on the heat capacity of the salt. Calcium chloride was found to be the most effective heat sink overall among the five heat sinks investigated here.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-06-08T07:00:00Z
      DOI: 10.1139/cjc-2018-0165
  • Medium effect on the α-effect for nucleophilic substitution reactions of
           p-nitrophenyl acetate with benzohydroxamates and m-chlorophenoxide in
           DMSO–H2O mixtures as contrasts with MeCN–H2O mixtures: comparing two
           very different polar aprotic solvent components
    • Authors: Ik-Hwan Um, Hyun-Jung Moon, Young-Hee Shin, Julian M. Dust
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A kinetic study is reported on nucleophilic substitution reactions of p-nitrophenyl acetate (1a) with three α-effect nucleophiles, benzohydroxamate (BHA–), p-methylbenzohydroxamate (MBHA–), and p-methyl-N-methylbenzohydroxamate (M2BHA–), and a reference nucleophile, m-chlorophenoxide (m-ClPhO–), in DMSO–H2O mixtures of varying compositions at 25.0 ± 0.1 °C. Second-order rate constants for the reactions with BHA– and MBHA– decrease upon addition of DMSO to the reaction medium up to 60 mol % DMSO and then increase thereafter only a little. In contrast, M2BHA– and m-ClPhO– become much more reactive as the DMSO content in the medium increases. Such contrasting medium effects on reactivity are consistent with the report that hydroxamic acids behave as OH acids in H2O but as NH acids in dipolar aprotic solvents (e.g., DMSO and MeCN). It has been concluded that BHA– and MBHA– form an equilibrium of a reactive form I with less reactive species II in DMSO–H2O mixtures and the position of the equilibrium is dependent on solvent compositions. BHA– and MBHA– exhibit the α-effect in H2O but not in in 90 mol % DMSO. In contrast, the α-effect yielded by M2BHA– increases steeply up to 70 mol % DMSO and then levels off thereafter.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-05-29T07:00:00Z
      DOI: 10.1139/cjc-2018-0103
  • A prelude to building mathematical models for polypeptide folding:
           analysis on the conformational potential energy hypersurface
           cross-sections of N-acetyl-glycyl-glycine-N′-methylamide
    • Authors: John Justine S. Villar, Logine Negm, Anita Rágyanszki, David H. Setiadi, Adrian Roy L. Valdez, Béla Viskolcz, Imre G. Csizmadia
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Finding a relationship on how a three-dimensional protein folds from its linear amino acid chain gets more complex with increasing chain length, so working on a smaller peptide conformational problem can provide initial ideas on what are the main molecular forces and how these influence the folding process. Following the study of conformations of amino acid units entering the proteins to understand the secondary structure of small peptides, this paper proposes mathematical models for the several two-rotor cross-sections of the five-dimensional N-acetyl-glycyl-glycine-N′-methylamide potential energy hypersurface (PEHS). These cross-sections are extracted along the first glycine subunit, with its coordinates fixed at the five energy minima of the glycine diamide. The resulting mathematical models yield an average RMSE of 1.36 kJ mol−1 and an average R2 of 0.9923 with respect to energy values obtained from DFT calculations. The minima geometries obtained from these models are also in good agreement with DFT-optimized energy minima conformers. An important aspect of this study also tackles the relationship between the PEHS of the glycyl-glycine diamide and its glycine subunits. It has been observed that there are deviations up to 28.35 kJ mol−1 and 29.52 kJ mol−1 between the PEHS cross-sections along γL and γD conformations, respectively, in the first glycine subunit. This may suggest that there are significant backbone–backbone intermolecular forces acting on the dipeptide. The abovementioned findings can help in developing more complex mathematical models for polypeptide folding from amino acid subunits.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-05-28T07:00:00Z
      DOI: 10.1139/cjc-2018-0017
  • Synthesis, reactivity, and antimicrobial properties of boron-containing
           4-ethyl-3-thiosemicarbazide derivatives
    • Authors: Ryan S. Scott, Alex J. Veinot, Darcie L. Stack, Patrick T. Gormley, B. Ninh Khuong, Christopher M. Vogels, Jason D. Masuda, Felix J. Baerlocher, Tyson J. MacCormack, Stephen A. Westcott
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The addition of 4-ethyl-3-thiosemicarbazide to benzaldehyde and boronic acid containing derivatives afforded the corresponding thiosemicarbazones (1–3) or benzodiazaborines (4–6) depending on the position of the boronic acid within the ring. All compounds have been characterized fully including an X-ray diffraction study of the methoxy-containing benzodiazaborine 6. Attempts to coordinate thiosemicarbazones 2 and 3 to palladium(II) acetate were unsuccessful; however, addition of the non-boron-containing derivative 1 to palladium afforded complex 7 whose molecular structure was determined by an X-ray diffraction study. The initial bioactivities of compounds 1–7 were examined against two fungi, Aspergillus niger and Saccharomyces cerevisiae, and two bacteria, Bacillus cereus and Pseudomonas aeruginosa.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-05-24T07:00:00Z
      DOI: 10.1139/cjc-2018-0108
  • Facile approach for synthesis of stable, efficient, and recyclable ZnO
           through pulsed sonication and its application for degradation of
           recalcitrant azo dyes in wastewater
    • Authors: G. Kumaravel Dinesh, Rameshkumar Saranya
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      In the present study, the ultrasound in pulsed mode was used as a part of an advanced oxidation method. The influence of the pulsed ultrasound mode for the preparation of the zinc oxide (ZnO) wurtzite nanoparticle was investigated. The catalysts synthesized were analysed using SEM, TEM, EDAX, BET surface area, XRD, and DRS to study their morphological and structural characterizations. The ZnO nanoparticles exhibited a highly hexagonal structure from pulsed sonication synthesis route. The efficiency of the decolourization of the reactive red 4 (RR4) dye was studied under different operation parameters such as dye concentration, initial solution pH, oxidant (e.g., H2O2) concentration, and catalyst loading. The hybrid combined process of pulsed sonolysis, pH (4.0), H2O2 (17.64 mmol), and catalyst (0.35 g/L) achieved 97% degradation and 87.5% chemical oxygen demand removal in about 20 min of reaction time. The cyclic degradation studies of RR4 removal with 0.35 g/L of ZnO showed the reusability of catalyst up to the fifth removal cycle with negligible loss in the catalytic performance. GC–MS study, used for the detection of the RR4 intermediates, revealed the oxidation–reduction reaction by the reactive radicals proceeded via the reductive cleavage of the azo bonds. The studied process, based on the pulsed ultrasound, is found to be effective for the degradation of RR4 dye.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-05-23T07:00:00Z
      DOI: 10.1139/cjc-2017-0696
  • An engineered one-site aptamer with higher sensitivity for label-free
           detection of adenosine on graphene oxide
    • Authors: Zijie Zhang, Juewen Liu
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The 27-nucleotide DNA aptamer for adenosine and ATP, originally selected by the Szostak lab in 1995, has been a very popular model system for biosensor development. This unique aptamer has two target binding sites, and we recently showed that it is possible to remove either site while the other one still retains binding. From an analytical perspective, tuning the number of binding sites has important implications in modulating sensitivity of the resulting biosensors. In this work, we report that the engineered one-site aptamer showed excellent signaling properties with a 2.6-fold stronger signal intensity and also a 4.2-fold increased detection limit compared with the wild-type two-site aptamer. The aptamer has a hairpin structure, and the length of the hairpin stem was systematically varied for the one-site aptamers. Isothermal titration calorimetry and a label-free fluorescence signaling method with graphene oxide and SYBR Green I were respectively used to evaluate binding and sensor performance. Although longer stemmed aptamers produced better adenosine binding affinity, the signaling was quite independent of the stem length as long as more than three base pairs were left. This was explained by the higher affinity of binding to GO by the longer aptamers, cancelling out the higher affinity for adenosine binding. This work further confirms the analytical applications of such one-site adenosine aptamers, which are potentially useful for improved ATP imaging and for developing new biosensors.
      Citation: Canadian Journal of Chemistry
      PubDate: 2018-02-07T08:00:00Z
      DOI: 10.1139/cjc-2017-0601
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