Canadian Journal of Chemistry
ISSN / EISSN : 0008-4042 / 1480-3291
Published by: Canadian Science Publishing (10.1139)
Total articles ≅ 25,260
Latest articles in this journal
Canadian Journal of Chemistry pp 1-11; https://doi.org/10.1139/cjc-2021-0147
Ionic liquids (ILs) have remarkable properties and applications in many areas of science. Phosphonium ILs have become important because of their unique chemical and thermal stabilities. The present work is focused on the synthesis, characterisation, physicochemical properties, and microbial toxicity assessment of phosphonium ILs bearing seven different fatty acid anions. The structures of the synthesised ILs were confirmed by 1H and 13C nuclear magnetic resonance (NMR) and FTIR spectroscopy. Physicochemical properties such as density and viscosity of pure ILs were measured at temperatures ranging from 298.15 to 313.15 K. The experimental density decreased, whereas the viscosity increased with an increasing number of carbon atoms in the anion. The derived properties were also found to be anion dependent. The thermal decomposition temperature was investigated by TGA. Subsequently, the toxicity profile of the ILs was determined for selected Gram positive and Gram negative bacteria and some species of fungi in terms of minimum inhibitory concentrations (MIC). The results show that the antimicrobial activities of the ILs are strongly related to the structures of the ILs, where an increase in toxicity was observed with increasing alkyl group chain length of the fatty acid anion.
Canadian Journal of Chemistry, Volume 99, pp 942-949; https://doi.org/10.1139/cjc-2021-0042
The intermolecular interaction between the constituent components of liquid mixtures can be revealed by ultrasonic analysis. In the present study, interaction of nitrazepam with methyl alcohol has been studied and presented using ultrasonic tools. The investigation involves calculation of ultrasonic velocity (υ), density (ρ), viscosity (η), and the associated derived parameters. The specific acoustic impedance (Z), isentropic compressibility (β), relaxation time (τ), intermolecular free length (Lf), and solvation number (Sn) are calculated to reveal the interaction information. The solvent–solvent and solute–solvent interaction between nitrazepam and alcohol molecules is considered. To see the impact of nitrazepam with alcohol in an ordinary day to day scenario, the investigation was carried out under normal temperature (303–313 K) and pressure conditions. The results indicate increased molecule association of nitrazepam in the presence of alcohol. This study suggests the presence of a synergistic depressants effect when nitrazepam is used with alcohol.
Canadian Journal of Chemistry; https://doi.org/10.1139/cjc-2021-0234
N-heterocyclic carbenes [1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene 1a (IMes) or 1,3-bis(2,6-di-iso-propylphenyl)imidazolidene 1b (SIPr)] react with the polarized alkenes 2 and 4 to form the crystalline betaines 3a, 3b and 5a. Furthermore, a one-pot reaction between an aldehyde, malonitrile, and an imidazolium salt of an N-heterocyclic carbene has been developed for the efficient preparation of betaine 5a without isolation of the free carbene. Full characterization data, including X-ray crystal structures, is reported for the three synthesized betaines. The structures of the betaines 3a, 3b and 5a shed new light on the initial products formed in the reactions between N-heterocyclic carbenes and compounds containing polarized double bonds.
Canadian Journal of Chemistry, Volume 99, pp 956-963; https://doi.org/10.1139/cjc-2021-0045
In the present study, for the first time, walnut bloom (WB) powder was used as a natural and economic sorbent for the removal of methylene blue (MB) from an aqueous solution. This new biosorbent was characterized using the following techniques: scanning electron microscopy (SEM), X-ray diffraction (XRD), COHNS, BET (Brunauer–Emmett–Teller) analysis, and Fourier transform infrared (FTIR) spectroscopy. MB removal efficiency and its adsorption onto WB powder were tested in a batch system by varying parameters such as initial dye concentration, contact time, pH, temperature, and dosage of biosorbent in which the removal percentages of ∼92% was achieved under the optimum conditions. Equilibrium data and adsorption isotherms fit well with the Langmuir model (R2 = 0.999, 0 < RL< 1) with a maximum monolayer adsorption capacity of 46 mg g−1. The chemical kinetics of MB adsorption followed the pseudo second-order model. Also, the magnitude of thermodynamic functions identified the removal of MB. ΔH° of –7.32 kJ mol−1 and ΔS° of –4.32 kJ mol−1 indicated the spontaneity, exothermicity, and favorability of the adsorption process at room temperature.
Canadian Journal of Chemistry, Volume 99, pp 983-990; https://doi.org/10.1139/cjc-2021-0030
Porphyrin-based photosensitizers are conventional photodynamic agents that are used clinically. However, their clinical applications have been overshadowed by poor water solubility. In addition, they have weak tumor selectivity, which may cause undesirable side effects. The preparation of novel porphyrin derivatives has been explored for potential applications in photodynamic therapy (PDT). To achieve this goal, lactose-conjugated porphyrin nanoparticles (Lac-Por NPs) have been synthesized and characterized. PDT with Lac-Por NPs exhibited tumor-specific cytotoxicity in lactose receptor-overexpressing HepG2 cells in vitro and in vivo. In summary, we designed and synthesized lactose conjugate porphyrins with enhanced water solubility and tumor selectivity. This work expands the application range of porphyrin-based photosensitizers for cancer treatment.
Canadian Journal of Chemistry pp 1-9; https://doi.org/10.1139/cjc-2021-0100
Crystallization of DNL-6, a silicoaluminophosphate (SAPO) based molecular sieve with the RHO topology, was investigated under both the hydrothermal synthesis (HTS) and dry-gel conversion (DGC) conditions. Crystallization of DNL-6 under the HTS conditions is rather fast. But a combination of crystallization under the DGC conditions and reducing reaction temperature slow down the reactions, allowing for intermediates to be captured. Under the DGC conditions, DNL-6 crystallizes through a semi-crystalline layered phase. The nature of this intermediate is aluminophosphate (AlPO) rather than SAPO with most P atoms having a local environment of P(–O–Al)3(OH). The surfactant (cetyltrimethylammonium chloride) used for synthesis appears to be part of the layered intermediate. Si is directly incorporated in the DNL-6 framework via SM II mechanism when the semi-crystalline AlPO phase is transforming to DNL-6 with the assistance of a very small amount of water. Both the structure directing agent and the surfactant play a role in the formation of DNL-6, as they were found within the final synthesized products. SEM data show that hydrothermal synthesis produces a much more crystalline product. The facts that the semi-crystalline layered phase was also observed in the powder X-ray diffraction patterns of the solid samples obtained under the HTS conditions and that the evolution of the local structure around P and Al in the intermediate phases are similar imply that under the reaction conditions employed in the present study, the formation pathways of DNL-6 under the HTS and DGC conditions appear to have some similarities.
Canadian Journal of Chemistry; https://doi.org/10.1139/cjc-2021-0228
Arc melted and drop tube processed Cu – 68.5 at. % Co alloy has been subjected to differential thermal analysis (DTA). The liquidus temperature determined from the DTA curves in the arc melt sample (1664 K) was found to be close to phase diagram estimate of 1662 K. In contrast as a result of liquid phase separation in the drop tube samples, the values obtained in the powders were much lower mainly because the compositions of the demixed phases vary from that of the parent melt. The liquidus temperature of the 850 + μm powders was 1632 K while that of the < 38 μm sieve size powder was 1616 K. This variance is due to the asymmetric nature of the metastable phase diagram of the system.
Canadian Journal of Chemistry pp 1-7; https://doi.org/10.1139/cjc-2021-0180
Recent recognition of the soluble form of the amyloid-beta (Aβ) peptide as a neurotoxic agent in Alzheimer’s disease (AD) has spurred the development of agents to target this species. Because Aβ is known to chelate metal ions in solution, metal-based therapeutics are uniquely suited to exploit this affinity, where coordination to Aβ has been shown to impact the neurotoxicity of the peptide. Ruthenium(II)–arene complexes are unique candidates for evaluation, as one face of the molecule is blocked by the hydrophobic arene ring, while coordination to the Aβ peptide can occur on the other side of the molecule. We have prepared and evaluated two Ru(II)–arene complexes with chelating quinoline-based ligands, Ru1 and Ru2, for their respective anti-amyloid abilities. Although both complexes decreased the aggregation of soluble Aβ, Ru1 displayed promise in disrupting formed aggregates of the peptide. These findings represent an exciting new avenue for therapeutic development in AD, where both sides of the aggregation equilibrium are affected.
Canadian Journal of Chemistry; https://doi.org/10.1139/cjc-2021-0239
4-(tert-Butyl)-2-trityl-6-(di-(2-picolyl)amine)phenol, LH, was prepared from paraformaldehyde, 4-(tert-butyl)-2-tritylphenol and di-(2-picolyl)amine. Reaction with Zn(N(SiMe3)2)2 gave LZnN(SiMe3)2. The complex was shown by X-ray diffraction study, variable temperature NMR and DFT calculations to coordinate only one pyridine ligand, which allows for fast and facile complex isomerisation. LZnN(SiMe3)2 was active in rac-lactide polymerization, but in contrast to previous complexes of this type did not show any evidence for isotactic monomer enchainment via a catalytic-site mediated chain-end control mechanism. Addition of alcohol led to increased activity, but the complex was unstable in the presence of free alcohol.
Canadian Journal of Chemistry; https://doi.org/10.1139/cjc-2021-0244
We synthesize and develop 1,3-dihydro-2H-imidazo[4,5-b]phenazine-2-thione as a ratiometric chemosensor for recognition of Hg2+ in DMSO/H2O (v/v = 9:1) binary solution. We rationally introduce the phenazine imidazole group as fluorophore and the thione moiety as recognition site to bind Hg2+. Interestingly, the chemosensor shows ultrasensitive response for Hg2+ and the lowest limit of detection is 0.167 nM. In addition, it can also separate Hg2+ from aqueous solution with excellent ingestion capacity, and the adsorption ratio is up to 96%. Furthermore, ion test strips based on the chemosensor are fabricated to conveniently and efficiently detect Hg2+.