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  Subjects -> CHEMISTRY (Total: 849 journals)
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    - CHEMISTRY (598 journals)
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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 32)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 227)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 14)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 13)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 164)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 212)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 285)
Biochemistry Insights     Open Access   (Followers: 5)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 110)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
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: 12)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 174)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 150)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 243)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 11)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 56)
Dalton Transactions     Full-text available via subscription   (Followers: 19)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 9)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)

        1 2 3 | Last

Journal Cover Canadian Journal of Chemistry
  [SJR: 0.364]   [H-I: 57]   [10 followers]  Follow
    
   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]
  • XEOL spectroscopy of lanthanides in aqueous solution
    • Authors: Astrid Jürgensen
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      As part of an ongoing study of the electronic interactions between solute and solvent molecules, a method for X-ray excited optical luminescence (XEOL) analysis of aqueous solutions was developed at the double-crystal monochromator beamline (DCM) of the Canadian Synchrotron Radiation Facility (CSRF). It was tested using a series of solutions containing lanthanide ions. The samples were contained in a sample holder for liquids with a 3 μm Mylar window separating them from the vacuum (≤3 × 10−6 torr, 1 torr = 133.3224 Pa) in the solid state absorption chamber of the DCM beamline. Terbium, samarium, and dysprosium have 4 intense and narrow luminescence peaks between 450 and 700 nm, well separated from the luminescence peak of the Mylar window between 300 and 425 nm. The intensity of the rare earth (RE3+) luminescence peaks was lower for the solutions than for solid RECl3·6H2O. In part, this was caused by the lower RE3+ concentration in the solutions than in the solid. In addition, the solvent (water) acts as a quencher. The disorder and the molecular motion in the solution increase the availability of nonradiative de-excitation pathways. A high concentration of SO42− in the solution enhanced the luminescence intensity, probably by inhibiting some nonradiative de-excitation pathways. This study has shown that it is in principle possible to investigate the luminescence of aqueous solutions with XEOL spectroscopy. Furthermore, it is possible to use this technique as a quantitative analytical tool for concentrated luminescent solutions and to study the shielding effects of anions in the solution that increase the luminescence intensity.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-07-13T12:32:12Z
      DOI: 10.1139/cjc-2017-0038
       
  • High ozone chemisorption by using metal–cluster complexes: a DFT study
           on the nickel-decorated B12P12 nanoclusters
    • Authors: Ali Shokuhi Rad
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      In the present study, by using first-principle study within the density functional theory (DFT), we investigated the ozone (O3) chemisorption on the surface of pristine and nickel-decorated B12P12 nanoclusters. The important emphasis of this study is to follow changes in the electronic structures of the aforementioned nanoclusters upon adsorption of the O3 molecule. Although we found strong chemisorption of O3 on a pristine nanocluster (–282.7 kJ/mol), significant increases in adsorption were found by modifying the nanocluster’s surface. Firstly, we found there are three possible sites on the surface of the nanocluster for nickel (Ni) decoration. For each Ni-decorated nanocluster, we searched its potential for adsorption of O3 by using quantum chemical calculations. Depending on the location of decorated Ni, we found considerable increased values of O3 adsorption energy (–340.8, –376.8, and –382.4 kJ/mol). We carried out calculations by taking into account the values of adsorption energy, bond distance, dipole moment study, charge analysis, frontier orbital analysis, and density of states of all relaxed systems.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-07-04T07:00:00Z
      DOI: 10.1139/cjc-2017-0204
       
  • Heat-induced coacervation for purification of Lycium barbarum
           polysaccharide based on amphiphilic polymer–protein complex formation
    • Authors: Juan Han, Yun Wang, Tong Chen, Xiaowei Hu, Lei Gu, Xu Tang, Lei Wang, Liang Ni
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Heat-induced coacervation of triblock copolymer solution was described, and its application in the purification of Lycium barbarum polysaccharide (LBP) was investigated. The formation of coacervate micelles–protein complex combined with the incompatibility between coacervate micelles and polysaccharide made it an ideal system for the separation of protein and LBP. This separation process was governed by a series of parameters including polymer concentration, amount of crude LBP solution, and pH. In the primary coacervation extraction process, LBP was preferentially distributed to dilute phase with a high recovery ratio of 82%, whereas 87% of protein was partitioned to the coacervate phase. The coacervate micelles–protein interaction and the interphase potential was regulated by temperature and electrolytes, respectively, which contributed to the recovery and recycling of the polymer. After phase separation, LBP was precipitated with the addition of ethanol. The FTIR spectrum was used to identify LBP. In addition, the antioxidant activity of LBP was measured.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-06-08T07:00:00Z
      DOI: 10.1139/cjc-2017-0008
       
  • Dimension reduction in conformational analysis: a two-rotor mathematical
           model of amino acid diamide conformational potential energy surface
    • Authors: John Justine S. Villar, Adrian Roy L. Valdez, David H. Setiadi, Béla Fiser, Béla Viskolcz, Imre G. Csizmadia, Anita Rágyanszki
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The conformational potential energy surface (PES) of a molecule provides insights into the relative stability of the possible foldamers. However, the time and space complexity of electronic structure calculations, commonly used to generate PES, increases exponentially with an increasing number of atoms. The use of mathematical functions to model the topology of conformational PES is an alternative to more computer-intensive quantum chemical calculations, but the choice and complexity of functions used are crucial in achieving more accurate results. This paper presents a method to illustrate the topology of amino acid diamide PESs through a linear combination of a Fourier series and a mixture of Gaussian functions. Results yield a significantly small error, with an average RMSE of 4.9946 kJ mol−1 for all fits, which suggest that these functions may be used to represent the topology of the PESs, with around twofold order of magnitude decrease in computational time, with respect to DFT electronic structure calculations. This study ultimately aims to provide a foundation for a framework on building polypeptide PES from individual amino acid PESs.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-06-07T07:00:00Z
      DOI: 10.1139/cjc-2017-0124
       
  • Quantum chemistry calculation of reaction pathways of carboxyl groups
           during coal self-heating
    • Authors: Xuyao Qi, Haibo Xue, Haihui Xin, Ziming Bai
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      During coal self-heating, reactions of carboxyl groups feature in the evolution of the spontaneous combustion of coal. However, their elementary reaction pathways during this process still have not been revealed. This paper selected the Ar–CH2–COOH as a typical carboxyl group containing structure for the analysis of the reaction pathways and enhancement effect on the coal self-heating process by quantum chemistry calculations. The results indicate that the hydrogen atoms in carboxyl groups are the active sites, which undergo the oxidation process and self-reaction process during coal self-heating. They both have two elementary reactions, namely (i) the hydrogen abstraction of –COOH by oxygen and the decarboxylation of the –COO· free radical and (ii) the hydrogen abstraction of –COOH and its pyrolysis. The total enthalpy change and activation energy of the oxidation process are 76.93 kJ/mol and 127.85 kJ/mol, respectively, which indicate that this process is endothermic and will occur at medium temperatures. For the hydrogen abstraction of –COOH by hydrocarbon free radicals, the thermal parameters are 53.53 kJ/mol and 56.13 kJ/mol, respectively, which has the same thermodynamic properties as the oxidation process. However, for the pyrolysis, the thermal parameters are –42.53 kJ/mol and 493.68 kJ/mol, respectively, and is thus exothermic and would not occur until the coal reaches high temperatures. They affect heat accumulation greatly, generate carbon dioxide, and provide new active centers for enhancing the coal self-heating process. The results would be helpful for further understanding of the coal self-heating mechanism.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-06-02T07:00:00Z
      DOI: 10.1139/cjc-2017-0176
       
  • Naphthalene formation pathways from phenyl radical via vinyl radical
           (C2H3) and vinylacetylene (C4H4): computational studies on reaction
           mechanisms and kinetics
    • Authors: Mingrui Wei, Tingting Zhang, Shunxi Li, Guanlun Guo, Dongju Zhang
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The reaction mechanisms of PAH formation from phenyl radical (C6H5) to naphthalene via C2H3 (C2H3-Path) and C4H4 (C4H4-Path) were investigated by the G3(MP2, CC) method. The hydrogen abstraction, ring closure, cis–trans isomerization, and disproportionation reactions were considered, as well as their occurred sequence. The results showed that H-abstraction reactions occurred more easily than H-dissociation reactions. The cis–trans conversion reactions in sub-routes of C2H3-Path and C4H4-Path provided the largest barriers of 51, 53, and 36 kcal/mol along their routes, which illustrated that the cis–trans isomerization was energetically costly in the PAH formation process. The entrance barriers of C2H2-Path, C2H3-Path, and C4H4-Path are 6, 8, and 3 kcal/mol, respectively, which indicates that it is easier to add C4H4 to C6H5 compared with adding C2H2 to C2H3. C2H3 additions were highly exothermic with reaction energies greater than 110 kcal/mol, and compared with C2H2 additions, C2H3 additions were irreversible. However, C2H2-Path, C2H3-Path and C4H4-Path involved energy barriers of 20, 32, and 36 kcal/mol, respectively. Considering the high temperature in combustion and the approximate concentrations of C2H3 and C4H4, all three of these pathways could lead to naphthalene in some combustion flames.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-26T07:00:00Z
      DOI: 10.1139/cjc-2017-0090
       
  • Radiation chemistry of molecular compounds and polymers by soft X-ray
           spectroscopy and microscopy
    • Authors: Jianjun Yang, Jian Wang
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Soft X-ray-induced radiation chemistry in selected Fe molecular compounds and some aliphatic polymers was studied using soft X-ray absorption spectroscopy, and scanning transmission X-ray microscopy. X-ray absorption near-edge structure (XANES) spectroscopy was used to elucidate the radiation chemistry. The results show that damage to the Fe molecular complexes involves Fe-ligand bond breaking, ligand damage, and subsequent photoreduction of Fe(III) if it is not tightly bonded to oxygen. Upon radiation damage, polymer PAN primarily undergoes chemical structure changes without mass loss, PECA experiences chemical structure changes as well as small mass loss, while PPC and PEC suffer large mass loss with chemical structure changes. These studies are not only important to X-ray analysis of radiation sensitive materials but also are valuable to the applications of X-ray lithography and other types of nanofabrication involving photoresist.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-26T07:00:00Z
      DOI: 10.1139/cjc-2017-0140
       
  • Easy but not straightforward: base and solvent effect on the synthesis of
           luminescent europium 1,3-di(thien-2-yl)propane-1,3-dionate coordination
           complexes
    • Authors: Lidia Armelao, Alice Carlotto, Federica Mian, Jacopo Tessarolo, Gregorio Bottaro, Marzio Rancan
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Reaction between EuCl3 and the ligand 1,3-di(thien-2-yl)propane-1,3-dione (L) leads to luminescent coordination compounds [EuL3(EtOH)2] (1), [EuL2(i-PrOH)4]Cl (2) and [EuL3(i-PrOH)2] (3), isolated as single crystals in high yield (70%–95%). The Eu/β-diketonate ratio is tuned from 1:2 to 1:3 through the variation of the alcoholic solvent (ethanol and isopropanol) or the base (pyridine and NaOH). In all compounds, Eu3+ ions are eight-coordinated, and in 2, the molecules are arranged in an H-bond supported supramolecular 1D chain. These compositional and structural differences are reflected also on the absorption and emission properties.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-26T07:00:00Z
      DOI: 10.1139/cjc-2017-0200
       
  • Electrochemical determination of thrombin with molecularly imprinted
           polymers and multiwalled carbon nanotubes
    • Authors: Shaoming Yang, Lingling Li, Xiaorong Zhang, Peiling Shang, Shaoqing Ding, Wenling Zha, Wenyuan Xu
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The preparation and application of reagentless electrochemical thrombin molecularly imprinted sensors were studied using multiwalled carbon nanotubes as sensitivity-enhanced materials. The molecularly imprinted polymer film was prepared by the electropolymerization of o-phenylenediamine with thrombin as the template molecule onto the surface of multiwalled carbon nanotubes modified glassy carbon electrode. After removing thrombin, the poly-o-phenylenediamine molecularly imprinted film was obtained with specific recognition for thrombin. Using the poly-o-phenylenediamine molecularly imprinted polymers as the electron probe, the electrochemical molecularly imprinted sensor was fabricated for the detection of the protein thrombin. Under optimized experimental conditions, the sensor exhibited a good linear response from 10.0 fg/mL to 1.0 μg/mL for thrombin, with correlation coefficient 0.999 and a low detection limit of 1.7 fg/mL. The fabricated molecularly imprinted sensor can be applied to the detection of thrombin in actual sample bovine serum with satisfactory results.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-26T07:00:00Z
      DOI: 10.1139/cjc-2017-0010
       
  • High-performance reduced graphene oxide – red phosphorous composites
           anodes for lithium batteries and soft X-ray near-edge structure studies
    • Authors: Dongniu Wang, Lucia Zuin, David Muir
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A solution method was developed to synthesize reduced graphene oxide (RGO) – red phosphorous (RP) composites. The uniform distribution of RP particles into three-dimensional conductive RGO network was obtained. Due to both improved electronic structure and mechanical properties, the hybrids delivered a high lithium storage capacity with superior rate performance. For the first time, the electronic structure, as revealed by phosphorous (P) L-edge and lithium (Li) K-edge X-ray absorption near-edge structure (XANES), provides spectroscopic evidence to identify the lithiated products and solid electrolyte interphase. Charge distribution in between RP and RGO was also found by XANES, facilitating the anchoring of active RP into RGO surface.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-24T07:00:00Z
      DOI: 10.1139/cjc-2017-0121
       
  • Successive outermost-to-core shell directionality of the protonation of
           poly(propyl ether imine) dendritic gene delivery vectors
    • Authors: Abirami Lakshminarayanan, Narayanaswamy Jayaraman
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The protonation behaviour of polycationic compounds has direct relevance to their ability to condense and deliver nucleic acids. This report pertains to a study of the protonation behaviour of polycationic poly(propyl ether imine) (PETIM) dendritic gene delivery vectors that are constituted with tertiary amine core moiety and branch sites, n-propyl ether linkages, and primary amine peripheries. The ability of this series of dendrimers to condense nucleic acids and mediate endosomal escape was studied by unravelling the protonation behaviour of the dendrimers aided by pH metric titrations and 1H and 15N NMR spectroscopies. The results demonstrate protonation of the primary and tertiary amines of outermost-to-core shells occurring in a successive stepwise fashion, in contrast to other polycationic vectors. Theoretical calculations based on the Ising model rationalize further the finer details of protonation at each shell. The protonation pattern correlates with the endosomal buffering and nucleic acid condensation properties of this PETIM-based dendritic gene delivery vectors. The study establishes that the protonation behaviour is a critical and essential parameter to assess the gene condensation and delivery vector properties of a polycationic compound.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-24T07:00:00Z
      DOI: 10.1139/cjc-2017-0153
       
  • Synthesis and fluorescence studies of novel bisarylmethylidene derivatives
           of 2-methoxy-2-methyl-1,3-dioxan-5-one
    • Authors: Mohammad M. Mojtahedi, Kiana Darvishi, M. Saeed Abaee, Mohammad R. Halvagar
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The first general procedure is described for the synthesis of novel bisarylmethylidenes of 2-methoxy-2-methyl-1,3-dioxan-5-one 1. Thus, several derivatives of 3 are obtained rapidly in high yields by reacting 1 with different aldehydes in the presence of catalytic quantities of pyrrolidine in EtOH at room temperature. Upon completion of the reactions, products are obtained directly by spontaneous precipitation avoiding time consuming and expensive chromatographic separations. All products were characterized by proton and carbon NMR spectroscopy methods, and in one case, the proposed structure was elucidated by X-ray crystallography, confirming the Z stereochemistry for the olefinic C=C bonds. Due to showing different colours in solid and solution states, products were studied for their photophysical properties as well.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-24T07:00:00Z
      DOI: 10.1139/cjc-2017-0099
       
  • Investigation of amorphous to crystalline phase transition of sodium
           titanate by X-ray absorption spectroscopy and scanning transmission X-ray
           microscopy
    • Authors: Jian Liu, Biqiong Wang, Mohammad N. Banis, Zhiqiang Wang, Ruying Li, Jian Wang, Yongfeng Hu, Tsun-Kong Sham, Xueliang Sun
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Nanostructured sodium titanate has great potential for various applications such as sodium-ion batteries, photocatalysts, and waste treatment. Understanding the phase-transition mechanism in sodium titanate after annealing is fundamentally important to tune the structure, morphology, and property for targeted applications. In this work, we adopted amorphous sodium titanate grown on carbon nanotubes by an atomic layer deposition technique as a reference and used X-ray absorption spectroscopy (XAS) and scanning transmission X-ray microscopy (STXM), as well as a high-temperature in situ X-ray diffraction (XRD) technique, to elucidate the phase-transition mechanism of sodium titanate from amorphous to crystalline upon annealing from 25 °C to 900 °C. XAS and XRD analysis disclosed that anatase TiO2 first formed in the matrix of amorphous sodium titanate at 500 °C and then recrystallized into Na0.23TiO2 at 700 °C and 900 °C. XAS studies also revealed that the Ti atoms in sodium titanate were oxidized during the annealing process and reached an oxidation state about 3.8+ for Na0.23TiO2. The elevated annealing temperature increased the coordination number of Ti atoms and the crystallinity of sodium titanate. STXM chemical map provided spatial information and visualized evidence on the phase transition among amorphous sodium titanate, anatase TiO2, and Na0.23TiO2 in the samples annealed at intermediate temperatures (500 °C and 700 °C). This work provides a comprehensive understanding on the evolution of sodium titanate, in terms of crystal structure, electronic structure, chemical environment, and morphology, under different post annealing conditions.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-17T07:00:00Z
      DOI: 10.1139/cjc-2017-0132
       
  • Investigation of solvation effects on iron(II) and iron(III) salt
           solutions by X-ray absorption spectroscopy
    • Authors: Aimee Maclennan, Yongfeng Hu
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The effects of solvation on iron salts has been studied by in situ X-ray absorption spectroscopy (XAS). It was seen that the solvated iron is significantly different from the solid precursor when dissolved in a variety of common solvents. Changes in the chemical and electronic properties of the solvated species make it essential to understand what is happening in solution prior to choosing appropriate reference materials for the interpretation of X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) data. An understanding of the complexity of analyzing liquid systems by XAS is gained from this research.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-17T07:00:00Z
      DOI: 10.1139/cjc-2017-0141
       
  • Cholic acid dimers as invertible amphiphilic pockets: synthesis, molecular
           modeling, and inclusion studies
    • Authors: Meng Zhang, Nicolas Levaray, Josée R. Daniel, Karen C. Waldron, X.X. Zhu
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Two dimers of cholic acid were synthesized through simple covalent linkers. The dimers form invertible molecular pockets in media of different polarity; hydrophobic pockets are formed in water and hydrophilic pockets are formed in organic media. Fluorescence studies show that pockets formed by these dimers can serve as invertible hosts for the hydrophobic guest pyrene and the hydrophilic guest coumarin 343. The molecular pocket also enhances dissolution of the weakly soluble cresol red sodium salt in organic media. Molecular modeling was performed to better understand the host–guest complexation process of the invertible amphiphilic pockets. The calculated free energy changes indicate that the two dimers form the most stable complexes with coumarin 343 at a host to guest ratio of 2:2, whereas the host to guest ratio differs in the formation of complexes with pyrene for the two dimers. The dimer with the shorter, less flexible linker seems to form host–guest complexes that are more stable in both water and organic solvents.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-17T07:00:00Z
      DOI: 10.1139/cjc-2016-0621
       
  • A simple and effective approach for catalytic reductive dechlorination of
           aromatic compounds
    • Authors: Tamer E. Youssef, Hanan H. Mohamed
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      An efficient process for the preparation of 2(3),9(10),16(17),23(24)-octa(n-hexyl)cobalt(II)phthalocyanine, ((n-hexyl)8CoPc) (2) was described. The novel cobalt(II)phthalocyanine was characterized by spectroscopic methods. It was employed as a catalyst for the room temperature reductive dechlorination of chlorinated aromatic compounds (CACs). The results were showed that the CACs were completely dechlorinated within 110–120 min.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-16T07:00:00Z
      DOI: 10.1139/cjc-2016-0567
       
  • A simple azoquinoline based highly selective colorimetric sensor for CN−
           anion in aqueous media
    • Authors: Omer Kaan Koc, Hava Ozay
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Azoquinoline based sensor AZQ was designed and synthesized as a new molecular ion sensor containing an azo group in its structure. The structural characterization of AZQ was carried out using FTIR, NMR, mass, and elemental analysis. Then, the interaction of AZQ with anions was observed visually and UV–vis measurements were made in EtOH/H2O (1:1, v/v) solvent mixture. As a result of this investigation, it was determined that AZQ is a fast and highly selective sensor for CN− ions. The solution colour of AZQ changed from light yellow to orange only in the presence of CN− ions. The limit of detection of AZQ was calculated as 2.6 μmol/L from anion titration experiments. Also, to identify the interaction mechanism of AZQ with CN− ions, 1H NMR spectra of AZQ in the presence of CN− anions were recorded and the structure was proposed for AZQ-CN− host–guest complex.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-16T07:00:00Z
      DOI: 10.1139/cjc-2017-0163
       
  • The application of XANES for the examination of silver, gold, mercury, and
           sulfur on the daguerreotype surface
    • Authors: M.S. Kozachuk, R.R. Martin, T.K. Sham, M. Robinson, A.J. Nelson
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      X-ray absorption near edge structure (XANES) spectroscopy was used to study a freshly prepared reference daguerreotype surface as the first step in devising improved methods for the conservation of these important historic artifacts. The results are consistent with the formation of alloy image particles. Interdiffusion of gold and silver has led to the development of a silver–gold alloy; the composition varies with depth. The amount of gold appeared to be elevated in the highlighted regions of the image, whereas shadow regions have lower levels of gold on the surface. The apparent increase in gold within the highlighted region may be due to the larger surface area presented by an array of small image particles. The mercury used to develop the daguerreian image showed no evidence of oxidation while a mercury–silver alloy was detected. Sulfur-based contaminants are also detected. The implications of these findings are discussed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-15T07:00:00Z
      DOI: 10.1139/cjc-2017-0062
       
  • Large-scale hollow nanoparticle identification by X-ray absorption
           spectroscopy
    • Authors: Yuanhong Tang, Zhiqiang Wang, Dongniu Wang, Jian Wang, Tsun-Kong Sham
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Large-scale SiO2 hollow nanoparticles were synthesized by a sol-gel method. The composition, morphology, and chemical bonding information of SiO2 hollow nanoparticles were studied by X-ray absorption near edge structure (XANES) and scanning transmission X-ray microscopy (STXM). XANES at the Si L-edge and K-edge reveal the characteristics of hollow nanoparticles, which are essentially amorphous SiO2 with a slightly longer Si–O bond than SiO2 nanoparticles on average and deficiencies in oxygen. Individual SiO2 hollow spheres were also examined using STXM, which provides spectromicroscopic information, as well as the absolute thickness, of the sample.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-15T07:00:00Z
      DOI: 10.1139/cjc-2017-0104
       
  • Dendrimer and dendrimer–conjugate protein complexes and protein
           coronas
    • Authors: Junjie Chen, Mark M. Banaszak Holl
      Pages: 1 - 4
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Dendrimers and dendrimer conjugates are widely employed for biological applications such as bio-imaging and drug delivery. Understanding the interaction between dendrimers and their biological environment is key to evaluating the efficacy and safety of these materials. Proteins can form an adsorbed layer, termed a “protein corona”, on dendrimers in either a non-specific or specific fashion. A tight-binding, non-exchangeable corona is defined as a “hard” corona, whereas a loosely bound, highly exchangeable corona is called a “soft” corona. Recent research indicates that small molecules conjugated to the polymer surface can induce protein structural change, leading to tighter protein–dendrimer binding and further protein aggregation. This “triggered” corona formation on dendrimer and dendrimer conjugates is reviewed and discussed along with the existing hard or soft corona model. This review describes the triggered corona model to further the understanding of protein corona formation.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-15T07:00:00Z
      DOI: 10.1139/cjc-2017-0198
       
  • PAMAM dendrimers in drug delivery: loading efficacy and polymer morphology
    • Authors: P. Chanphai, L. Bekale, S. Sanyakamdhorn, D. Agudelo, G. Bérubé, T.J. Thomas, H.A. Tajmir-Riahi
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The binding efficacy of anticancer drugs doxorubicin and tamoxifen with polyamidoamine (PAMAM-G4) dendrimers was studied in aqueous solution at physiological pH. The results of multiple spectroscopic methods, transmission electron microscopy (TEM), and molecular modeling of conjugated drug–polymer were examined. Structural analysis showed that drug–polymer conjugation occurs mainly via H-bonding and hydrophilic and hydrophobic contacts. Doxorubicin forms a more stable conjugate with PAMAM-G4 than tamoxifen. The drug loading efficacy was 40%–50%. The TEM images showed major changes in the PAMAM morphology upon drug encapsulation. Modeling showed that drug is located in the polymer surface and in the internal cavities. PAMAM nanoparticles are capable of transporting doxorubicin and tamoxifen in vitro. This minireview presents the most recent work performed with the dendrimers demonstrating their usefulness for drug delivery in cancer therapy.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-11T07:00:00Z
      DOI: 10.1139/cjc-2017-0115
       
  • Scanning transmission X-ray microscopy studies of chromium hydroxide
           hollow spheres and nanoparticles formed by gamma radiation
    • Authors: Zhiqiang Wang, Leena Alrehaily, Jiju Joseph, Jungsook Clara Wren, Jian Wang, Tsun-Kong Sham
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Amorphous chromium-containing solid nanoparticles and hollow spheres were formed as the intermediate product during the synthesis of Cr2O3 by gamma radiolysis of dichromate solution. Scanning transmission X-ray microscopy (STXM) is applied to investigate the electronic structure and chemical composition of this intermediate product (solid nanoparticles and hollow spheres). The STXM result obtained at O K-edge and Cr L3,2-edge confirms that chromium in the sample exists as Cr3+ and that the solid nanoparticles and hollow spheres are both Cr(OH)3. Combined with other techniques, a mechanism for gamma radiation induced formation of Cr2O3 nanoparticles via Cr(OH)3 intermediates from dissolved dichromate is proposed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-11T07:00:00Z
      DOI: 10.1139/cjc-2017-0142
       
  • Dendrimers for ocular drug delivery
    • Authors: Michael G. Lancina, Hu Yang
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Existing methods of administering ocular drugs are limited in either their safety or efficiency. Nanomedicine therapies have the potential to address this deficiency by creating vehicles that can control drug biodistribution. Dendrimers are synthetic polymeric nanoparticles with a unique, highly organized branching structure. In recent years, promising results using dendrimer vehicles to deliver ocular drugs through different routes of administration have been reported. In this minireview, we briefly summarize these results with emphasis on the dendrimer modifications used to target different ocular structures.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-11T07:00:00Z
      DOI: 10.1139/cjc-2017-0193
       
  • Magnetic alginate beads with high basic dye removal potential and
           excellent regeneration ability
    • Authors: K.Z. Elwakeel, A.A. El-Bindary, A.Z. El-Sonbati, A.R. Hawas
      Pages: 1 - 9
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The adsorption of crystal violet (CV) dye onto magnetic alginate (MAlg) composite from aqueous solutions was studied. Experiments were carried out as function of contact time, dosage, temperature, pH, and CV concentration in the solutions. Optimum CV uptake was observed at equilibrium pH 7 and most of the CV was sorbed within 30 min. The equilibrium adsorption data were analyzed using two common adsorption models: Langmuir and Freundlich. The results revealed that Langmuir isotherm fit the experimental results well. The maximum adsorption capacity obtained from Langmuir isotherm equation was 0.113 mmol g−1 at 298 ± 1 K. The kinetics adsorption of CV onto MAlg composite was investigated using the pseudo first-order and pseudo second-order kinetic models. The results showed that the adsorption of CV onto MAlg composite followed pseudo second-order kinetic model. Thermodynamic data indicated that the adsorption process is an endothermic and spontaneous reaction. Due to its outstanding adsorption capacities, MAlg composite is an excellent adsorbent for the removal of CV. The composite regeneration was greater than 98.6% with 0.01 mol/L HCl, and MAlg composite could be repeatedly utilized for CV removal with negligible loss in sorption capacity.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-08T07:00:00Z
      DOI: 10.1139/cjc-2016-0641
       
  • On molecular topological properties of diamond-like networks
    • Authors: Muhammad Imran, Abdul Qudair Baig, Hafiz Muhammad Afzal Siddiqui, Rabia Sarwar
      Pages: 1 - 13
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The Randić (product) connectivity index and its derivative called the sum-connectivity index are well-known topological indices and both of these descriptors correlate well among themselves and with the π-electronic energies of benzenoid hydrocarbons. The general n connectivity of a molecular graph G is defined as [math] and the n sum connectivity of a molecular graph G is defined as [math], where the paths of length n in G are denoted by [math] and the degree of each vertex vi is denoted by di. In this paper, we discuss third connectivity and third sum-connectivity indices of diamond-like networks and compute analytical closed results of these indices for diamond-like networks.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-06T07:00:00Z
      DOI: 10.1139/cjc-2017-0206
       
  • The influences of different substituents on spectral properties of
           rhodamine B based chemosensors for mercury ion and application in EC109
           cells
    • Authors: Wenqi Du, Yu Cheng, Weixin Shu, Baoying Wu, Zhineng Kong, Zhengjian Qi
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Six rhodamine-based “turn-on” fluorescence chemosensors (L1–L6) with different substituents for mercury (Hg2+) were readily synthesized and investigated; they displayed high selectivity and chelation enhanced ratiometric fluorescence change and colorimetric change with Hg2+ among the metal ions examined. Based on UV and fluorescence spectral data, the effects of different substituents on spectral properties of the probes were presented and discussed. The detection limit of Hg2+ to probe L1 was as low as 50 nmol/L because of its electron-donating group. Theoretical calculation also supported the process of reaction. Confocal laser scanning microscopy experiments showed that probe could be used to detect Hg2+ in living cells.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-05-02T07:00:00Z
      DOI: 10.1139/cjc-2017-0017
       
  • Defect specific luminescence dead layers in CdS and CdSe
    • Authors: R.A. Rosenberg
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      CdS and CdSe are often used in optoelectronic devices whose effectiveness may be dictated by defects in the near surface region. Luminescence is one of the main tools for studying such defects. The energy dependence of the X-ray excited optical luminescence (XEOL) spectra of these materials enables the extraction of the depth dependence of the defect distribution. Normal and time-gated XEOL spectra were obtained from these materials in the energy range 600–1500 eV. We find that the results can best be understood in terms of a luminescence dead layer whose width depends on the position of the defect level in the band gap.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-28T07:00:00Z
      DOI: 10.1139/cjc-2017-0126
       
  • A dynamic look on molecular symmetry
    • Authors: Máximo Barón, Alex D. Bain, Romina S. Conde
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      J.H. van’t Hoff’s seminal paper variously titled as either: Chemistry in Space, The Placement of Atoms in Space or other with similar wording, depending on the language it was published in, suggested that the structure of a molecule would be independent of its physical state: solid, liquid, vapor, gaseous, or in solution. However, this is definitely not true so much so that during the last decades many examples have accumulated showing that the structure of a molecule in a crystalline solid can differ substantially from its structure in solution. This would have important consequences not only on how molecules are structurally described and the way they react, but also that molecular symmetry may not be a static property and has to be considered from a dynamic point of view. To add additional evidence to this conception, we took advantage of a family of trans-1,4-di- and tetra-substituted cyclohexane derivatives that appear to have a centre of symmetry but show a substantial dipole moment in solution. In the present work, we used the trans-1,4-dicarboxymethylcyclohexane and its 1,4-dibrominated derivative and were able, through dipole moment determinations IR, Raman, NMR studies, and computational calculations with the SpinWorks, MOPAC, and MOLDEN programs, to confirm our assumption that the molecular symmetry and the molecular structure are dependent on the environment.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-24T07:00:00Z
      DOI: 10.1139/cjc-2016-0657
       
  • Improved large-scale synthesis and characterization of small and medium
           generation PAMAM dendrimers
    • Authors: Mario Ficker, Valentina Paolucci, Jørn B. Christensen
      Pages: 1 - 11
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Dendrimers are promising polymers for biomedical applications; however, most dendrimer formulations have failed to move from laboratory science to upscaled products for preclinical testing or GMP production. This publications reports on an improved large-scale PAMAM dendrimer synthesis that is suitable to manufacture large amounts of highly pure and monodisperse dendrimers of generations G0–G5. Furthermore, an extended analytical guideline how to characterize PAMAM dendrimers with NMR, HPLC, SEC-MALS, ESI, MALDI, UV–vis, fluorescence, and IR spectroscopy is provided.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-24T07:00:00Z
      DOI: 10.1139/cjc-2017-0108
       
  • Synthesis of the symmetrical methylene diesters from carboxylic ionic
           liquids
    • Authors: D. Gómora-Herrera, I.V. Lijanova, O. Olivares-Xometl, A. Toscano, N.V. Likhanova
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The reaction between carboxylic ionic liquids and dichloromethane, which provokes the formation of symmetrical methylene diesters, was carried out. The synthesis of these ionic liquid compounds was carried out in a microwave reactor, and the characterization by spectroscopic techniques of methylene diesters (methylene di-2-furoate, methylene di-2-picolinate, methylene dianthranilate, and methylene dioleate) is described and the crystal structures discussed. The crystal packing of methylene dianthranilate is characterized by trimer formation due to hydrogen bonding via interactions between the hydrogen atom of the primary amine group and the oxygen of the carboxylic group.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-24T07:00:00Z
      DOI: 10.1139/cjc-2017-0042
       
  • BF2 complexes of 1,3-diketones on the surface of phosphorus dendrimers:
           synthesis and study of the photoluminescence properties
    • Authors: Cédric Rouxel, Olivier Mongin, Aurélien Hameau, Armelle Ouali, Mireille Blanchard-Desce, Jean-Pierre Majoral, Anne-Marie Caminade
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Difluoroboron complexes of monomeric and dimeric diketones and of generations 0–4 of phosphorus dendrimers ended by diketone ligands are synthesized and characterized. Their photoluminescence properties are measured. All compounds exhibit an intense absorption band in the near UV region. Both model dimers and dendrimers show a marked hypsochromic shift of this absorption band compared with the monomeric difluoroboron complex. The fluorescence of the dioxaborine complex subunit in the multichromophoric dendritic architectures is quenched compared with the emission of the isolated monomeric fluorophore, presumably due to interactions between the terminal groups of dendrimers.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-19T07:00:00Z
      DOI: 10.1139/cjc-2017-0135
       
  • From optimized monovalent ligands to size-controlled dendrimers: an
           efficient strategy towards high-activity DC-SIGN antagonists
    • Authors: Stefania Ordanini, Giulio Goti, Anna Bernardi
      Pages: 1 - 10
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      This short review describes our work on the development of dendrimeric antagonists of DC-SIGN, a dendritic cells (DCs) receptor recognizing highly mannosylated structures and primarily involved in the recognition of viruses such as HIV. The structure of pseudo-di-mannoside and pseudo-tri-mannoside compounds was first finely modified to obtain DC-SIGN ligands that were more stable and selective than mannose. Their DC-SIGN affinity differences were amplified once presented on multivalent dendrimer-like scaffolds, including poly-alkyne terminated and phenylene-ethynylene rod-like ones. Libraries of mannosylated dendrimers were synthesized, improving their stability and maximizing their monodispersity. The effect of the dendrimers valency, structure, and size on DC-SIGN affinity and antiviral potency was investigated. Both the valency and the topology of the architectures were revealed as key parameters for activity optimization, together with the intrinsic affinity of the monovalent ligand. The stability, rigidity, and length of the scaffolds were also tuned. The design of geometrically adapted scaffolds afforded one of the most potent inhibitors of DC-SIGN mediated HIV infections to date. This monodispersed, not cytotoxic, and highly active compound was also tested with DCs; its internalization into endolysosomal compartments and its ability to induce the overexpression of signaling molecules makes it a good precursor to produce pathogen-entry inhibitors with immunomodulant properties.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-19T07:00:00Z
      DOI: 10.1139/cjc-2017-0138
       
  • Theoretical study on the hydrolytic step in the biotransformation of
           β-hexachlorocyclohexane degraded by haloalkane dehalogenase LinB
    • Authors: Xiaowen Tang, Junjie Wang, Nan Zhao, Qingzhu Zhang, Wenxing Wang
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The hydrolytic process of LinB-catalyzed biotransformation of a notorious contaminant β-HCH was investigated in atomistic detail with a combined quantum mechanics/molecular mechanics approach. The Boltzmann-weighted averaging method amended by disproportionate effect analysis was showed to capture the fluctuation of a single molecule enzyme reaction. With the potential barriers of 18.7 and 2.6 kcal/mol, two elementary steps that refer to formation and decomposition of a tetrahedral intermediate are involved in the hydrolytic reaction, respectively. Polarized by Glu132, His272 serves as a proton carrier along the whole hydrolysis reaction. The electrostatic influence analysis highlighted residue Leu248 as a possible mutation target for rational design of LinB in enzyme modification. Further spatial location analysis provided explanation for the opposite effect of Asn38 toward the two elementary steps. Getting insight into the catalytic details and the structure and function of LinB can enrich the knowledge of it and promote its application in bioremediation of chlorinated hydrocarbon pollutants.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-19T07:00:00Z
      DOI: 10.1139/cjc-2016-0653
       
  • Kinetics and mechanism of phenoxide anions addition to 4-nitrobenzofurazan
           in aqueous solution
    • Authors: S. Ben Salah, T. Boubaker, R. Goumont
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Second-order rate constants (k1) for the σ-complexation of 4-nitrobenzofurazan 1 with four 4-X-substituted phenoxide anions 2a–2d (X = OCH3, CH3, H and Cl) were measured in aqueous solution at 20 °C. Using this series of phenoxide anions as a reference, the electrophilicity parameter (E) of this electrophile 1 has been evaluated according to Mayr’s approach. With the E value of –9.42, Mayr’s equation was found to correctly predict the rate constants for the reactions of 1 with hydroxide ion in H2O and a 1:1 ratio of H2O to CH3CN. However, the large βnuc value of 1.12 obtained in the present work is clearly consistent with a single electron transfer (SET) mechanism.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-11T07:00:00Z
      DOI: 10.1139/cjc-2016-0182
       
  • Effect of antifouling dendrimers and Au DENPs on the enhancement of PCR
           amplification
    • Authors: Haixia Zhang, Chen Peng, Aijun Li, Xiangyang Shi, Xueyan Cao
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The polymerase chain reaction (PCR) has been considered as one of the most fundamental techniques to amplify and analyze specific DNA fragments in the field of molecular biology and clinical medicine. Recently, a variety of nanoparticles (NPs) have been regarded as a novel method to enhance both the quality and yield of PCR technique. Herein, we report the use of generation 5 (G5) poly(amidoamine) (PAMAM) dendrimers and dendrimer-entrapped gold nanoparticles (Au DENPs) modified with polyethylene glycol (PEG) moieties and (or) acetyl groups as a novel class of enhancers to improve the PCR amplification. We set up the nonspecific PCR and two-round PCR as model systems to investigate mechanisms of enhanced PCR. Our results show that dendrimer-based derivatives seem to enhance the PCR specificity. It is worth noting that the modification of antifouling PEG significantly lowered the optimization capability of the corresponding dendrimers, although this inhibition effect can be remarkably compromised by the entrapment of Au NPs. Furthermore, we found that in the presence of Au NPs, the thermal conductivity induced by Au NPs could play the dominant role in the PCR optimization, whereas in the absence of Au NPs, the electrostatic interaction of the dendrimers with PCR components may be the major factor affecting the PCR system. Our results also showed that the optimal concentrations of the materials in the two test systems were very close, which indicates that the developed dendrimer derivatives with good thermal stability may be the efficient PCR additives for enhancing different PCR systems.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-05T07:00:00Z
      DOI: 10.1139/cjc-2017-0055
       
  • Synthesis of a poly(amidoamine) dendrimer having a
           1,10-bis(decyloxy)decane core and its use in fabrication of carbon
           nanotube/calcium carbonate hybrids through biomimetic mineralization
    • Authors: Shunichi Nishimura, Tomoyuki Tajima, Tatsuki Hasegawa, Tomoaki Tanaka, Yutaka Takaguchi, Yuya Oaki, Hiroaki Imai
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      A new dendritic dispersant of carbon nanotubes (CNTs) was synthesized and applied for the noncovalent functionalization of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The 1,10-bis(decyloxy)decane core of the poly(amidoamine) dendrimer strongly adhered to the sidewalls of CNTs to form CNT/dendrimer supramolecular nanocomposites having many carboxyl groups (–COOH) on the surface. Then, crystallization of calcium carbonate (CaCO3) by the CO2 diffusion technique in aqueous environments using the CNT/dendrimer supramolecular nanocomposites as scaffolds afforded monodisperse spherical CNT/CaCO3 nanohybrids consisting of CNTs and calcite nanocrystals. The morphologies of the SWCNT/CaCO3 hybrids and MWCNT/CaCO3 hybrids were almost the same.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-04-04T07:00:00Z
      DOI: 10.1139/cjc-2017-0022
       
  • Dye rejection membranes prepared from oxidized graphite particles
    • Authors: Anastasia Colomba, Mark C. Biesinger, Ranjith Divigalpitiya, Frank A. Brandys, Joe B. Gilroy
      Pages: 1 - 7
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      This article reports the comparison of different chemical methods to produce graphite-based particles with varying degrees of oxidation, as well as graphene oxide (GO) and pristine graphite (PG). Detailed physicochemical characterization of the resulting materials was carried out, highlighting structural differences and variable oxygen content. The particles were then used to produce supported membranes that were tested for the rejection of three different organic dyes (Rhodamine B, Methyl Blue, and Congo Red), and their performance was rationalized in terms of a combination of properties of the membranes and dyes. In particular, membranes produced using edge-oxidized graphite (EOG) showed comparable performance with those derived from GO in the removal of Congo Red, providing a promising alternative to the aforementioned membranes.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-03-27T12:56:07Z
      DOI: 10.1139/cjc-2016-0628
       
  • Strategies for penicillin V dendronization with cationic carbosilane
           dendrons and study of antibacterial properties
    • Authors: Elena Fuentes-Paniagua, José M. Hernández-Ros, Juan Soliveri, José L. Copa-Patiño, Rafael Gómez, Javier Sánchez-Nieves, F. Javier de la Mata
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Strategies to synthesize a cationic carbosilane dendron containing the antibiotic penicillin V potassium salt (PenVK) at the focal point are discussed. The preparation of such a compound requires the use of systems with no donor atoms such as N or S in their framework, because their presence favours the rupture of the penicillin β-lactam ring. The antibacterial activity of the new dendron containing ammonium groups, at the periphery, and the PenV moiety, at the focal point, against gram-positive Staphylococcus aureus strains was evaluated. These results were compared with those obtained for free PenVK, a related cationic dendron without a penicillin moiety at the focal point, and also compared with an equimolar mixture of this last dendron with free PenV. The data obtained indicate that, on one hand, the conjugation or interaction of PenV with cationic dendrons reduces its activity in comparison with free PenVK. On the other hand, the penicillin dendron is able to release the antibiotic in the presence of esterease, due to the breaking of the ester bond in this derivative.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-03-14T07:00:00Z
      DOI: 10.1139/cjc-2017-0059
       
  • Effects of polymer intercalation in calcium silicate hydrates on drug
           loading capacities and drug release kinetics: an X-ray absorption near
           edge structure study
    • Authors: Xiaoxuan Guo, Jin Wu, Yun-Mui Yiu, Yongfeng Hu, Ying-Jie Zhu, Tsun-Kong Sham
      Pages: 1 - 8
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Different calcium silicate hydrate (CSH)/polymer composites are synthesized by using a controlled precipitation reaction between calcium salt and silicate salt, followed by the addition of various polymer solutions at room temperature. X-ray absorption near edge structure (XANES) spectroscopy has been used to extensively investigate the structural changes after hybrid biomaterials formation and the drug–carrier interactions on the molecular level. We find that the polymers alter the structure of CSH to various degrees and that this behaviour further influences the drug loading capacities and drug release kinetics.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-03-08T08:00:00Z
      DOI: 10.1139/cjc-2016-0660
       
  • Impact of room temperature on pentacene thin film growth and electronic
           structure
    • Authors: Ru-Ru Ji, Qi Wang, Jia-Xin Hu, Steffen Duhm
      Pages: 1 - 5
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      The electronic structure and transport properties of organic thin films depend critically on the film structure. We have shown by means of ultraviolet photoelectron spectroscopy that the growth of vacuum-sublimed pentacene on highly oriented pyrolytic graphite substrates depends significantly on the room temperature and the substrate cleanness. At T = 291 K, all molecules adopt a flat lying orientation in the contact layer to a clean (vacuum-annealed) substrate, whereas at T = 303 K, some molecules are standing upright. On defect-rich substrates, the thin films are rather disordered for both temperatures and comprise standing and lying molecules.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-03-08T08:00:00Z
      DOI: 10.1139/cjc-2017-0021
       
  • Colloidal synthesis of Pt–In bimetallic nanoparticles for propane
           dehydrogenation
    • Authors: Xuchun Wang, Di Yang, Yong Xu, Jun Zhong, Qiao Zhang
      Pages: 1 - 6
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Recently, Pt-based bimetallic nanoparticles have drawn much attention because of their great catalytic performance and wide applications in diverse fields. In this work, we report that bimetallic Pt–In nanoparticles with uniform size distribution and controllable composition can be synthesized through a one-step, facile colloidal approach. Various characterization tools such as XRD, TEM, XPS, and synchrotron techniques have been used to characterize the as-obtained nanoparticles. It is demonstrated that the Pt and In elements are homogeneously distributed in the whole nanoparticle. The bimetallic Pt–In nanoparticles have shown great catalytic performance, including high activity, high selectivity, and high stability, for the propane dehydrogenation reaction to produce propene, one of the most important chemicals. The excellent catalytic performance makes Pt–In bimetallic nanoparticles promising catalysts in future industrial application.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-03-03T08:00:00Z
      DOI: 10.1139/cjc-2017-0033
       
  • Investigation of CeTi2O6- and CaZrTi2O7-containing glass–ceramic
           composite materials
    • Authors: Elham Paknahad, Andrew P. Grosvenor
      Pages: 1 - 12
      Abstract: Canadian Journal of Chemistry, e-First Articles.
      Glass–ceramic composite materials are being investigated for numerous applications (i.e., textile, energy storage, nuclear waste immobilization applications, etc.) due to the chemical durability and flexibility of these materials. Borosilicate and Fe–Al–borosilicate glass–ceramic composites containing brannerite (CeTi2O6) or zirconolite (CaZrTi2O7) crystallites were synthesized at different annealing temperatures. The objective of this study was to understand the interaction of brannerite or zirconolite-type crystallites within the glass matrix and to investigate how the local structure of these composite materials changed with changing synthesis conditions. Powder X-ray diffraction (XRD) and Backscattered electron (BSE) microprobe images have been used to study how the ceramic crystallites dispersed in the glass matrix. X-ray absorption near edge spectroscopy (XANES) spectra were also collected from all glass–ceramic composite materials. Examination of Ti K-, Ce L3-, Zr K-, Si L2,3-, Fe K-, and Al L2,3-edge XANES spectra from the glass–ceramic composites have shown that the annealing temperature, glass composition, and the loading of the ceramic crystallites in the glass matrix can affect the local environment of the glass–ceramic composite materials. A comparison of the glass–ceramic composites containing brannerite or zirconolite crystallites has shown that similar changes in the long range and local structure of these composite materials occur when the synthesis conditions to form these materials or the composition are changed.
      Citation: Canadian Journal of Chemistry
      PubDate: 2017-02-21T08:00:00Z
      DOI: 10.1139/cjc-2016-0633
       
 
 
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