Metalloporphyrin 착물과 Nitrogenous Bases간의 화학평형반응 = Equilibrium Reaction for the Coordination Nitrogenous Bases to Metalloporphyrin(M=Zn^2+, Cu^2+, Ni^2+)

다국어 초록 (Multilingual Abstract)

The axial ligation of nitrogenous bases(pyridine, imidazole, 1-methylimidazole, 2,6-lutidine) to the four coordinated metallo-tetrakis(ortho-chlorophenyl)porphyrin and metallotetraphenylporphyrin are studied in a noncoordinating solvent, dichloromethane.
Equilibrium constants for the ligation reactions of metalloporphyrin were determined using the spectrophotometric method.
The order of the coordination capability of the ligands was given by;
1-Methylimidazole>Imidazole>Pyridine>2, 6-Lutidine
For the equilibria of reactions of ZnTPP and Zn(o-Cl)TPP with polar solvents(DMF, DMSO), the equilibrium constants(logK) were 2.74 and 1.39 for DMSO, and 1.89 and 1.22 for DMF
Nitrogenous bases (1-Melm, 1m, Py, 2,6-Lut) to the four coordinated Zn(o-Cl)TPP and ZnTPP have been investigated in various solvents, dimethylformamide, dimethylsulfoxide, dirhlorome-thane, acetone, and chloroform at several temperature(15℃, 25℃ and 35℃) The values of thermodynamic parameters, ΔH(kcal/mol) and ΔS(eu) were determined from the temperature effect on the equilibrium constants.
In addition to the temperature effect, the solvent effects on the equilibrium constant of ligation reaction were discussed.
For the case of a coordinating solvent(DMSO and DMF), the solvent effects on the equilibrium reaction between the metalloporphyrin and nitrogenous bases were able to explain in terms of a competition between the nitrogenous bases and solvent for the vacant coordination site of ZnTPP and Zn(o-Cl)TPP.