New copper complexes with bipyrazolic ligands: Synthesis, characterization and evaluation of the antibacterial and catalytic properties

Coordination complexes constructed from pyrazole-acetamide and pyrazole-quinoxaline: effect of hydrogen bonding on the self-assembly process and antibacterial activity

Two mononuclear coordination complexes of N-(2-aminophenyl)-2-(5-methyl-1H-pyrazol-3-yl)acetamide (L1), namely [Cd(L1)2Cl2] (C1) and [Cu(L1)2(C2H5OH)2](NO3)2 (C2) and one mononuclear complex [Fe(L2)2(H2O)2](NO3)2·2H2O (C3), obtained after in situ oxidation of L1, have been synthesized and characterized spectroscopically. As revealed by single-crystal X-ray diffraction, each coordination sphere made of two heterocycles is completed either by two chloride anions (in C1), two ethanol molecules (in C2) or two water molecules (in C3). The crystal packing analysis of C1, C2 and C3, revealed 1D and 2D supramolecular architectures, respectively, via various hydrogen bonding interactions, which are discussed in detail. Furthermore, evaluation in vitro of the ligands and their metal complexes for their antibacterial activity against Escherichia coli (ATCC 4157), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923) and Streptococcus fasciens (ATCC 29212) strains of bacteria, revealed outstanding results compared to chloramphenicol, a well-known antibiotic, with a normalized minimum inhibitory concentration as low as 5 μg mL-1.

Preparation and Uses of Chlorinated Glycerol Derivatives

Crude glycerol (C3H8O3) is a major by-product of biodiesel production from vegetable oils and animal fats. The increased biodiesel production in the last two decades has forced glycerol production up and prices down. However, crude glycerol from biodiesel production is not of adequate purity for industrial uses, including food, cosmetics and pharmaceuticals. The purification process of crude glycerol to reach the quality standards required by industry is expensive and dificult. Novel uses for crude glycerol can reduce the price of biodiesel and make it an economical alternative to diesel. Moreover, novel uses may improve environmental impact, since crude glycerol disposal is expensive and dificult. Glycerol is a versatile molecule with many potential applications in fermentation processes and synthetic chemistry. It serves as a glucose substitute in microbial growth media and as a precursor in the synthesis of a number of commercial intermediates or fine chemicals. Chlorinated derivatives of glycerol are an important class of such chemicals. The main focus of this review is the conversion of glycerol to chlorinated derivatives, such as epichlorohydrin and chlorohydrins, and their further use in the synthesis of additional downstream products. Downstream products include non-cyclic compounds with allyl, nitrile, azide and other functional groups, as well as oxazolidinones and triazoles, which are cyclic compounds derived from ephichlorohydrin and chlorohydrins. The polymers and ionic liquids, which use glycerol as an initial building block, are highlighted, as well.

An Improved Metal-to-Ligand Charge Transfer Mechanism for Photocatalytic Hydrogen Evolution

It is of great significance to fabricate a full-spectrum-active photocatalysts for more efficient utilization of solar energy. An improved metal-to-ligand charge transfer (MLCT) mechanism is proposed for a photocatalyst based on graphitic carbon nitride (g-C₃ N₄ ). UV/Vis spectroscopy indicates that the as-prepared photocatalyst absorbs light at λ<1100 nm. The rather stable photocatalyst is found to be 26.1 times more active in photocatalytic hydrogen evolution (868.9 μmol h^-1  g^-1 ) than bulk g-C₃ N₄ (B-CN) under visible light. The material exhibits high activity under near-infrared (NIR) irradiation (49.1 μmol h^-1  g^-1 ). The mechanism of photocatalytic activity and stability are investigated by both experiment and theory. This proposed mechanism may have great potential for engineering renewable photocatalysts in the future.