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
In this paper,the electric absorption spectra of axial coordination of Zn[Val-TPP] with imidazole was inverstigated.Coordination number and equilibrium constants of axial coordination reaction were measured by visible...In this paper,the electric absorption spectra of axial coordination of Zn[Val-TPP] with imidazole was inverstigated.Coordination number and equilibrium constants of axial coordination reaction were measured by visible spectra techniques.The changes of standard molar enthapy Δ rH o m and standard molar entropy Δ rS o m of reaction were obtained from the plot of lnK vs 1/T. The experimental results showed that both Δ rH o m and Δ rS o m of coordination reaction were negative values.展开更多
The electric absorption spectra of axial coordination reactions of tailed phenylalanine tetraphenylporphyrinato cobalt(Ⅱ) Co[Phe-TPP]with imidazole(Im),2 Methyl imidazole(2 MeIm) and N Methylimidazole(N MeIm) have be...The electric absorption spectra of axial coordination reactions of tailed phenylalanine tetraphenylporphyrinato cobalt(Ⅱ) Co[Phe-TPP]with imidazole(Im),2 Methyl imidazole(2 MeIm) and N Methylimidazole(N MeIm) have been studied.The standard equilibrium constant K and stoichiometric number n of reaction were measured by visible spectroscopy.The changes of standard molar enthalpy Δ rH m and standard molar entropy Δ rS m of the reaction were obtained from the plots of lnK υs 1/T.展开更多
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.
文摘In this paper,the electric absorption spectra of axial coordination of Zn[Val-TPP] with imidazole was inverstigated.Coordination number and equilibrium constants of axial coordination reaction were measured by visible spectra techniques.The changes of standard molar enthapy Δ rH o m and standard molar entropy Δ rS o m of reaction were obtained from the plot of lnK vs 1/T. The experimental results showed that both Δ rH o m and Δ rS o m of coordination reaction were negative values.
文摘The electric absorption spectra of axial coordination reactions of tailed phenylalanine tetraphenylporphyrinato cobalt(Ⅱ) Co[Phe-TPP]with imidazole(Im),2 Methyl imidazole(2 MeIm) and N Methylimidazole(N MeIm) have been studied.The standard equilibrium constant K and stoichiometric number n of reaction were measured by visible spectroscopy.The changes of standard molar enthalpy Δ rH m and standard molar entropy Δ rS m of the reaction were obtained from the plots of lnK υs 1/T.
