Canadian Journal of Chemistry
Permanent URI for this communityhttps://hdl.handle.net/1807/67557
Published since 1929, this monthly journal reports current research findings in all branches of chemistry.
Below is a collection of manuscripts accepted for publication in CJC. These manuscripts have not undergone copy editing or page composition.
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Below is a collection of manuscripts accepted for publication in CJC. These manuscripts have not undergone copy editing or page composition.
By using TSpace for its journal article repository, CSP grants University of Toronto Libraries a universal non-exclusive license to distribute and preserve all content that CSP deposits in the repository. Copyright of all articles in CSP journals remains with the authors, or the authors' organization, unless specified otherwise, TSpace users must follow the usage rights set out on CSP's web site. Refer to CSP's License to Publish Forms for information on current licensing.
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Item Open Access 1,2-Dihydro-1,3,2-diazaborinine tautomer as an electron-pair donor in hydrogen-bonded complexes(Canadian Science Publishing, 2021-06-17) Alkorta, Ibon; Elguero, Jose; Del Bene, Janet EAb initio MP2/aug’-cc-pVTZ calculations have been carried out to investigate 1,2-dihydro-1,3,2-diazaborinine:HX complexes for HX = H+, HF, HCl, H2O, HCN, NH3, HCP, and HCCH. Most complexes are stabilized by linear, traditional hydrogen bonds except for those with H2O and NH3 which have bridging structures and nonlinear hydrogen bonds. H-atom transfer from N to B can occur in complexes with HF and HCl, with formation of a traditional F-H…N and a proton-shared Cl…H…N bond. The binding energies of the uncharged complexes range from 25 to 88 kJ.mol–1. Spin-spin coupling constants have been used to characterize these hydrogen-bonded complexes. Des calculs ab initio MP2/aug'-cc-pVTZ ont t effectus pour tudier les complexes 1,2-dihydro-1,3,2-diazaborinine:HX pour HX = H+, HF, HCl, H2O, HCN, NH3, HCP et HCCH. La plupart des complexes sont stabiliss par des liaisons hydrogne traditionnelles, linaires, l'exception de celles avec H2O et NH3 qui ont des structures pont et des liaisons hydrogne non linaires. Le transfert de l'atome d'hydrogne de N B peut se produire dans des complexes avec HF et HCl, avec formation d'une liaison F-HN traditionnelle et d'une liaison ClHN avec un proton comparti. Les nergies de liaison des complexes non chargs vont de 25 88 kJmol–1. Des constantes de couplage spin-spin ont t utilises pour caractriser ces complexes liaison l'hydrogne.Item Open Access A combined solid-state 17O NMR, crystallographic, and computational study of oxiranes(Canadian Science Publishing, 2020-04-14) Rinald, Andrew; Terskikh, Victor; Schatte, Gabriele; Wu, GangWe report the synthesis and solid-state 17O NMR characterization of three 17O-labeled oxiranes: (2S*,3S*)-2,3-bis(4-nitrophenyl)-[17O]oxirane, (2S*,3R*)-2,3-bis(4-nitrophenyl)-[17O]oxirane, and 2,2,3-triphenyl-[17O]oxirane. In addition, we have determined the crystal structure of (2S*,3R*)-2,3-bis(4-nitrophenyl)oxirane by X-ray crystallography. When the experimentally determined 17O NMR tensors for oxiranes (where the C–O–C bond angle is about 60°) are compared with those for dimethyl ether (where the C–O–C bond angle is 113°) and other R–O–R′ functional groups, we found that the highly constrained geometry of oxiranes results in distinct tensor orientations in the molecular frame of reference. The experimental results are complemented by quantum chemical computations. This study represents the first time that 17O chemical shift and quadrupole coupling tensors are simultaneously determined for oxirane compounds.Item Open Access A Comparative Analysis of Empirical Equations Describing Pressure Dependence of Equilibrium and Reaction Rate Constants(Canadian Science Publishing, 2016-09-28) Spooner, Jacob Alan; Weinberg, NohamGeneral properties of the empirical analytical functions used to describe the effect of pressure on rate and equilibrium constants in solution are reviewed and the effects of experimental errors on the accuracy of activation and reaction volumes predicted by these equations are compared. When the error levels are low (1-2%) and pressure ranges are small (0-1kbar) all functions perform well, but when fitting data with high error or extending to higher pressures special care must be taken in order to obtain reliable results. Analysis of the results from fitting the equations to simulated data as well as experimental data for Diels-Alder, Menshutkin, and methanolysis reactions allows us to propose a set of general recommendations when using these equations as a tool for obtaining accurate activation and reaction volumes.Item Open Access A Comparative Study of Boron-Containing and Boron-Omitted Capsaicinoids(Canadian Science Publishing, 2023-04-30) Ngô, Giao N.; Park, SunMin; Stack, Hailey M.; Rourke, Jillian; Melanson, Jennifer; Westcott, Stephen A.This study reports the synthesis and characterization of a limited number of novel boron-containing and boron-omitted capsaicinoids, providing 12 unique substrates. We have previously reported boron-containing capsaicinoids that showed improved bioactivity compared to capsaicin itself but have yet to test a series of analogous boron-omitted substrates as a direct comparison. The boron-containing capsaicinoids bear a pinacolboronate ester (Bpin) group, which was incorporated using an iridium catalyzed hydroboration reaction. We report that although nearly all compounds display moderate cytotoxic activity that bests that of capsaicin against human colon HCT116 cancer cells, the activity of our boron-omitted capsaicinoids surpasses that of the boron-containing analogues.Item Open Access A Computational Investigation into Nickel-Bis(Diselenolene) Complexes as Potential Catalysts for Reduction of H+ to H2(Canadian Science Publishing, 2017-10-31) Boychuk, Briana Terri Ann; Bushnell, Eric A.C.As a result of burning fossil fuels levels of greenhouse gases in our atmosphere are increasing at an alarming rate. Such an increase in greenhouse gases threatens our planet due to global climate change. To reduce the production of greenhouse gases we must switch from fossil fuels to alternative fuels for energy. The most viable alternative energy source involves the conversion of solar energy into chemical energy via the photocatalytic splitting of water to form molecular hydrogen. In the present work the Ni-bis(1,2-diamine-diselenolene) and Ni-bis(1,2-dicyano-diselenolene) complexes were studied using Density Functional Theory (DFT). From the results it was found that the 1,2-diamine-diselenolene and 1,2-dicyano-diselenolene nickel complexes catalyze the formation of H22(g) with overall reaction Gibbs energies of +8.7 kJ molItem Open Access A Computational Investigation Into The Catalytic Activity Of A Diselenolene Sulfite Oxidase Biomimetic Complex(Canadian Science Publishing, 2016-07-24) Bushnell, Eric A.C.Molybdenum is the only 4d-metal found in almost all life. One such molybdenum-containing enzyme is sulfite oxidase which also contains the dithiolene-molybdopterin ligand. Sulfite oxidase is essential in the degradation of sulfur containing compounds such as cysteine and methionine. Past work has shown parallels in the chemistry of dithiolene- and diselenolene-metal complexes. Thus, in this present work the O-atom transfer mechanism for a diselenolene sulfite oxidase biomimetic complex was investigated using computational tools. The results of which were compared to the analogous dithiolene biomimetic complex. From the results obtained the molybdenum-diselenolene sulfite oxidase biomimetic complex is able to catalyse the O-atom transfer and does so with a marginally lower value of ∆rGItem Open Access A Computational Investigation into the Electron-Transfer Kinetics and Thermodynamics of Hydrogen gas production by Ni(S2C2H2)2, Ni(Se2C2H2)2, and Ni(Te2C2H2) complexes(Canadian Science Publishing, 2024-04-30) Abidullah, Zakariya M; Patel, Heliben V; Broome, Joshua Alexander; Bushnell, Eric A.C.Fossil fuels are rapidly being depleted and releasing great amounts of greenhouse gases, causing harmful effects to the environment. Renewable energy such as solar energy is an alternative option instead of using fossil fuels. However, storing the energy harvested as H2 by the electrolysis of H2O requires an effective, cheap catalyst to be practical. Thus, Ni catalysts are a valid option to produce hydrogen gas. In this study, the thermodynamics, and kinetics of ET for the electrocatalytic production of H2 by analogous Ni-bis(dithiolene), Ni-bis(diselenolene), Ni-bis(ditellurolene) complexes were studied using DFT. Thermodynamically, it was found that all three catalysts catalyze the formation of H2 with similar energetic cost. However, for release of H2 the catalysts must be doubly protonated and triply reduced. While the first two reductions occur with low Gibbs activation energies the third reduction does not. Therefore, if a third reduction is required for electrocatalytic H2 production a large overpotential would be expected from our predictions.Item Open Access A Computational Investigation of the Thermodynamics and Kinetics of Multiple Single-Step Electron Transfers of Various Ni and Chalcogen Containing Complexes(Canadian Science Publishing, 2024-01-22) Broome, Joshua Alexander; Xiang, Lily; Murray, Tyler; Zaliskyy, Roman; Bushnell, Eric A.C.Continued increase in green house gas emissions will lead to irreversible and unpredictable damage to the environment and biosphere. CO2 alone contributes to about two-thirds of the energy imbalance causing climate change. The bulk of these CO2 emissions can be traced to fossil fuels, which presently account for 82% of this green house gas. Developing effective renewable-alternative fuel sources is crucial to mitigate the harmful effects of fossil fuels. One such alternative fuel source is molecular hydrogen, which can be produced by the photocatalytic splitting of water using metal-based catalysts. This study investigates the thermodynamics and kinetics associated with single-step protonations and reductions of Ni[(S2C2H2)(N2C2H4)], Ni[(Se2C2H2)(N2C2H4)], and Ni[(Te2C2H2)(N2C2H4)] complexes using DFT. Results found diselenolene to be the least endergonic for the formation of the triply reduced, doubly protonated species with a Gibbs protonation energy of 79.6 kJ mol-1. Ditellurolene and dithiolene were slightly more endergonic with Gibbs protonation energies of 87.7 kJ mol-1 and 91.6 kJ mol-1, respectively. The most thermodynamically favourable pathways were found to be the ECCEE pathway for dithiolene and diselenolene, whereas the CECEE mechanism was found to be most favourable for ditellurolene. Kinetically, it was found that there were two feasible pathways for all three complexes. The first was a CCEEE pathway and the second was a CECEE pathway. All complexes were found to have similar Gibbs activation energies.Item Open Access A Cyclopenta[hi]acephenanthrylene Bearing Two Benzoannelated [3.3.3]Propellane Units: Extension of Triptindane Chemistry(Canadian Science Publishing, 2016-11-15) Hackfort, Thorsten; Neumann, Beate; Stammler, Hans-Georg; Kuck, DietmarThe McMurry reaction of triptindan-9-one (2), a three-fold benzoannelated Cs-symmetrical [3.3.3]propellane ketone, gave trans-9,9’-bitriptindanylidene (5), a sterically crowded stilbene hydrocarbon bearing two E-oriented triptindane moieties, in good yield. Photoisomerization of 5 generated the corresponding cis-stilbene 8 in a photostationary E/Z-mixture (55 : 45), which adopts a similarly crowded C2-symmetrical conformation that is apparently static on the NMR timescale. Photocyclodehydrogenation of 5 via 8 in benzene solution afforded the title hydrocarbon 6, a 1,2,9,10-tetrahydrocyclopenta[hi]acephenanthrylene merged with two triptindane units, in 85% yield. X-ray structure analysis of 6 revealed an essentially planar phenanthrene unit but significant steric repulsion between the pairs of opposite methylene groups of the [3.3.3]propellane cores, giving rise to a C2-symmetrical conformation. Reaction of 2 under modified McMurry conditions (DME instead of THF as a solvent) gave the saturated dimer, 9,9’-bitriptindanyl 7, as a mixture of diastereomers. Attempts to synthesize “columnene” (4), an elusive barrelene derivative fused with two triptindane caps, by three-fold McMurry reaction of triptindane-9,10,11-trione (3) failed.Item Open Access A divergent synthesis to generate targeted libraries of inhibitors for endo-N-acetylglucosaminidases.(Canadian Science Publishing, 2017-09-13) Seo, Isaac K; Woo, Esther H; Cecioni, Samy; Vocadlo, David JCell active inhibitors of glycoside processing enzymes are valuable research tools that aid understanding the physiological roles of this diverse class of enzymes. endo-N-Acetylglucosaminidases have emerged as playing important roles in both mammals and human pathogens, however, metabolically stable cell active inhibitors of these enzymes are lacking. Here we describe a divergent synthetic strategy involving elaboration of a thiazoline core scaffold. We illustrate the potential of this approach by using the copper catalysed azide-alkyne click (CuAAC) reaction, in combination with a suitable catalyst to avoid poisoning by the thiazoline moiety, to generate a targeted panel of candidate inhibitors of endo-N-Acetylglucosaminidases and chitinases.Item Open Access A dynamic look on molecular symmetry(Canadian Science Publishing, 2017-04-10) Baron, Maximo; Bain, Alex D; Conde, Romina SoledadJ. H. vanâ t Hoffâ 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. But 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. In order 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 as well as the molecular structure are dependent on the environment.Item Open Access A Ground-State Complex Between Methyl Viologen and the Fluorescent Whitening Agent 4, 4’–bis (2-sulfostyryl)-biphenyl disodium salt: A Fluorescence Spectroscopy Study(Canadian Science Publishing, 2021-01-08) Armstrong, Emily J.; Galas, Henry; Wylie, R. Stephen; Zohrehvand, Shiva; van Stam, Jan; Evans, Christopher H.This study explores the quenching of the dianionic fluorescent whitening agent, NFW, by various substances, including methyl viologen (MV), in water and in the presence of Beta-cyclodextrin (β-CD). Results of a fluorescence spectroscopic examination of the β-CD-NFW system are presented. It was found that NFW forms a 1:1 inclusion complex with β-CD with an association constant of 2540 380 MItem Open Access A mechanistic study of anti HIV activities of antifungal peptides(Canadian Science Publishing, 2017-02-03) Omar, Ruchi; Yadav, ArpitaHIV patients are constantly at risk of developing internal fungal infection and are regularly prescribed antifungal medications. Several classes of antifungal agents have thus been developed to combat ever increasing cases of resistant strains of fungi. Azoles despite being the most popular clinical choice; are not devoid of side effects. Many antimicrobial peptides have also been tested in search of safe, non toxic antifungals but, none succeeded as commercial alternatives. Recent research attempts show continued interest in these compounds and the complexities associated. Some experimental observations indicate involvement of these antimicrobial peptides in enhancing the efficacy of anti HIV agents. We present here an inter-twined approach to deal with two fatal diseases, internal fungal infection and HIV infection. Several naturally occurring antimicrobial peptides have been studied for their possible interaction with the viral RNA primer binding site (template) through interactions other than base-pairâ base-pair type. Peptides have been prepared and docked into viral template utilizing extra precision, flexible ligand docking. Implicit solvent was added around the complex and MMGBSA interaction energies were computed. Druggability aspects were explored by calculating ADME related properties. A peptidomimetic compound has been strategically designed to introduce druggability features in the peptide maintaining its viral template inhibition capability. Designed peptidomimetic lead compound may help in obtaining non toxic anti HIV agents. This is the first study to suggest a plausible explanation for the anti HIV activity of antifungal peptides at the molecular level and corroborate experimental findings of synergistic effects of these peptides on anti HIV agents.Item Open Access A membrane-spanning macrocyclic bolaamphiphile lipid mimic of archaeal lipids(Canadian Science Publishing, 2016-07-03) Mitchell, Gavin Maxwell; Hesketh, Amelia; Lombardi, Christie; Ho, Cally; Fyles, Thomas M.The synthesis of a 72-membered macrocyclic tetraester bolaamphiphile is accomplished in six chemical steps from commercially available starting materials using copper-accelerated azide-alkyne coupling to close the macrocycle in high yield. Related diester amphiphiles and an acyclic tetraester bolaamphiphile were also prepared. The set of lipids bearing nitrophenyl phosphate head groups were incorporated into phospholipid vesicles but failed to undergo phosphate hydrolysis in basic conditions, undergoing efficient elimination in competition. The same lipid cores bearing phosphate-linked nitrobenzoxadiazole (NBD) head groups also incorporated into phospholipid vesicles and the NBD fluorescence was quenched with cobalt ions. The proportion of membrane-spanning bolaamphiphiles was determined from the ratio of cobalt quenching in the presence and in the absence of a detergent. The macrocyclic bolaamphiphile is incorporated into phospholipid vesicles such that 48 Âą 4% of the NBD head groups are in the outer leaflet, consistent with a membrane-spanning orientation. The acyclic bolaamphiphile is incorporated with 75 Âą 3% of the NBD head groups accessible to quencher in the absence of a detergent suggesting U-shaped incorporation in the outer leaflet of the bilayer membrane. In ring size and spanning ability, the macrocyclic bolaamphiphile mimics naturally occurring macrocyclic archaeal lipids.Item Open Access A new synthesis of (Z, Z)-11, 11-dimethoxy-6, 9-heneicosadiene and 2-((Z, Z)-1, 4-decadienyl)-2-ndecyl-1, 3-dioxolane, precursors of (Z, Z)-6, 9-heneicosadien-11-one, a pheromone component of the whitemarked tussock moth, Orgyia leucostigma (J.E. Smith) (Lepidoptera: Erebidae)(Canadian Science Publishing, 2022-02-12) Mayo, Peter Donald; Abeysekera, Sumudu Deepa; Silk, Peter J.; Magee, David I.The straightforward synthesis of two long-chain diene ketals, (Z, Z)-11, 11-dimethoxy-6, 9-heneicosadiene and 2-Item Open Access A New Thiophene-Functionalized Pyrene, Peropyrene, and Teropyrene via a Two- or Four-fold Alkyne Annulation and Their Photophysical Properties(Canadian Science Publishing, 2016-10-13) Yang, Wenlong; Monteiro, Jorge H.S.K.; de Bettencourt-Dias, Ana; Chalifoux, Wesley A.A thiophene-functionalized pyrene, peropyrene, and teropyrene were synthesized through a two- or four-fold alkyne annulation reaction promoted by triflic acid. All of the target compounds were fully characterized spectroscopically and the structure of the peropyrene analogue was unambiguously confirmed by X-ray crystallography. A significant red-shift in the absorption and emission properties as a function of extended conjugation was observed by UV-vis and fluorescence spectroscopy. This alkyne annulation strategy is a useful method for the conversion of smaller polycyclic aromatics to larger ones, such as nanographenes.Item Open Access A novel fluorescent sensor based on 4-(diethylamino)-2-(hydroxy)-phenyl imine functionalized naphthalimide for highly selective and sensitive detection of CN- and Fe3+(Canadian Science Publishing, 2019-01-13) Zhang, You-Ming; Han, BingBing; Mao, PengPeng; Chen, JinFa; Yao, Hong; Wei, Tai-Bao; Lin, QiIn this work, a novel sensor molecule HB1 based on 4-(diethylamino)-2-(hydroxy)-phenyl imine functionalized naphthalimide derivative was successfully designed and synthesized. Interestingly, the HB1 showed fluorescence identification ability for CN- in DMSO/H2O (8 : 2, v/v) solution. After addition of CN- into the HB1 solution, the fluorescence intensity of HB1 solution could be enhanced obviously. The anti-disturbance experiments demonstrated that other anions couldn’t interfere in the detection of CN-. On the other hand, the HB1 enable dual-channel (absorption and fluorescence) detection of Fe3+ in DMSO solution. With the addition of various metal ions into the HB1 solution, only Fe3+ induced the fluorescence emission of HB1 solution quenching and the color changing, and other metal ions couldn’t interfere in the detection of Fe3+. The LODs (limits of lowest detection) of HB1 for CN- and Fe3+ were 6.30 × 10-8 M and 3.95 × 10-8 M, respectively. Importantly, the real samples experiment was carried out by detecting CN- in bitter almonds. Meanwhile, ion test strips based on HB1 were fabricated, which could act as convenient and efficient test kits for detecting CN- and Fe3+.Item Open Access A novel fluorometric chemosensor based on imidazo[4,5-b]phenazine-2-thione for ultrasensitive detection and separation of Hg2+ in aqueous solution(Canadian Science Publishing, 2021-10-27) Huang, Qing; Li, Qiao; Zhang, Hai-Li; Zhu, Wei; Qu, Wen-Juan; Lin, Qi; Yao, Hong; Zhang, You-Ming; Wei, Tai-BaoWe synthesize and develop 1,3-dihydro-2H-imidazo[4,5-b]phenazine-2-thione as a ratiometric chemosensor for recognition of HgItem Open Access A novel hydrogen-bonded organic framework for the sensing of two representative organic arsenics(Canadian Science Publishing, 2020-01-22) Liu, Ting; Wang, Bin; He, Ru; Arman, Hadi; Schanze, Kirk S.; Xiang, Shengchang; Li, Dan; Chen, BanglinA novel fluorescent hydrogen-bonded organic framework with a double fold interpenetrated structure, HOF-22, has been successfully constructed and structurally characterized. HOF-22 is capable of sensitive detection of two representative organic arsenics from aqueous solution.Item Open Access A Novel MS3 Experiment for Quantifying Ions with a Linear Ion Trap(Canadian Science Publishing, 2018-03-31) Campbell, J. Larry; Collings, Bruce A.; Le Blanc, Yves; Hager, James W.Liquid chromatography coupled with tandem mass spectrometry has long been employed for the quantitation of molecules. With judicious selection of precursor and fragment ions, multiple-reaction monitoring assays can be developed rapidly for these experiments. However, there are cases where analyses struggle due to high background signals caused by matrix effects that interfere with the analytical signal. An alternative to MRMs involves using two stages of tandem mass spectrometry - an MS