he axial coordination reactions of tetraphenylporphinatocobalt (Ⅲ) chloride(Co TPPC1) with various imidazoles RIm ( HIm . imidazole; Melm , 2-methylimida-zole) were investigated in acetone and dichloromethand so...he axial coordination reactions of tetraphenylporphinatocobalt (Ⅲ) chloride(Co TPPC1) with various imidazoles RIm ( HIm . imidazole; Melm , 2-methylimida-zole) were investigated in acetone and dichloromethand solvents at different temper-atures. The reaction mechanisms were proposed and the differences between experi-mental results in the two solvents h ave been interpreted using the proposed mecha-nisms and rate equations for the first time , and the reaction scheme for the axial re-action of the metalloporphyrin has been developed. Hydrogen bonding plays an im-portant role in the reactions. The effects of various imidazoles for these reactionsand the solvents are reported. The comparison between iron and cobalt porphyrinsin the kinetics are discussed.展开更多
A thermodynamic study is reported for the coordination reaction of ZnT ( m-X)PP derivatives (X = NO2, Cl, OCH3, H or CH3) with various ligands L (L= imidazole (Im), 2-methylimidazole (Melm), clotrimidazole (CIM), imid...A thermodynamic study is reported for the coordination reaction of ZnT ( m-X)PP derivatives (X = NO2, Cl, OCH3, H or CH3) with various ligands L (L= imidazole (Im), 2-methylimidazole (Melm), clotrimidazole (CIM), imidazol-4-carboxaldehyde (4-CHOIm), unsymmetrical tetradentate copper Schiff base, Culm(p-C1), Ch(p-Br), and nickel Schiff base, Nilm(p-CI)), in dichloromethane solvent. Conversion of the four-coordinated ZnT( m-X)PP to the five-coordinated species is followed and isosbestic behavior is exhibited in the region among 450 and 700 nm. The reaction of a copper(II) or nickel(II) imidazolate Schiff base with ZnT( m-X)PP results in the formation of an imidazolate bridged heterobinuclear complex. The stochiometric number is unity for all axial ligands. The equilibrium constants were determined using the β band of ZnT( m-X)-PP in the 293–308 K range by the method of Rose and Drago. It increases with decrease in temperature, and ΔH0 0, Δ09 0. The stronger the nucleophilic ability of the axial ligand is, the larger the stability of the axial coordination product is. Hammet linear relationships and isoequilibrium relationships exist in the system studied.展开更多
文摘he axial coordination reactions of tetraphenylporphinatocobalt (Ⅲ) chloride(Co TPPC1) with various imidazoles RIm ( HIm . imidazole; Melm , 2-methylimida-zole) were investigated in acetone and dichloromethand solvents at different temper-atures. The reaction mechanisms were proposed and the differences between experi-mental results in the two solvents h ave been interpreted using the proposed mecha-nisms and rate equations for the first time , and the reaction scheme for the axial re-action of the metalloporphyrin has been developed. Hydrogen bonding plays an im-portant role in the reactions. The effects of various imidazoles for these reactionsand the solvents are reported. The comparison between iron and cobalt porphyrinsin the kinetics are discussed.
基金National Natural Science Foundation of China (No.29871018Tianjin Natural Science Foundation
文摘A thermodynamic study is reported for the coordination reaction of ZnT ( m-X)PP derivatives (X = NO2, Cl, OCH3, H or CH3) with various ligands L (L= imidazole (Im), 2-methylimidazole (Melm), clotrimidazole (CIM), imidazol-4-carboxaldehyde (4-CHOIm), unsymmetrical tetradentate copper Schiff base, Culm(p-C1), Ch(p-Br), and nickel Schiff base, Nilm(p-CI)), in dichloromethane solvent. Conversion of the four-coordinated ZnT( m-X)PP to the five-coordinated species is followed and isosbestic behavior is exhibited in the region among 450 and 700 nm. The reaction of a copper(II) or nickel(II) imidazolate Schiff base with ZnT( m-X)PP results in the formation of an imidazolate bridged heterobinuclear complex. The stochiometric number is unity for all axial ligands. The equilibrium constants were determined using the β band of ZnT( m-X)-PP in the 293–308 K range by the method of Rose and Drago. It increases with decrease in temperature, and ΔH0 0, Δ09 0. The stronger the nucleophilic ability of the axial ligand is, the larger the stability of the axial coordination product is. Hammet linear relationships and isoequilibrium relationships exist in the system studied.
