锌卟啉配合物轴配反应的光谱及电子效应

The Visible Spectra and Electronic Effects in Axial Coordination Reaction of Zinc Porphyrin Complexes

用紫外－可见分光光度计研究了三种新型空间不对称金属席夫碱和四种取代咪唑与间位取代四苯基卟啉锌（ZnT（m－X）PP，X＝NO2，Cl，OCH3，H，CH3）在CH2Cl2中的轴向配位反应的紫外－可见吸收光谱，发现在450－700nm间存在等吸光点；采用Rose－Drago数据处理方法确定了各体系在25℃时平衡常数，发现所研究的35个配位反应体系的配位数均为1，各配体与锌卟啉配位反应的εβ／εα及平衡常数均分别与卟啉环上取代基的Hammett参数间存在线性自由能关系．

A thermodynamic study is reported for the coordination reaction of three new metalimidazolate complexes of unsymmetrical tetradentate schiff bases and four substituted imidazoleswith zinc meta-substituted tetraphenylporphyrins (ZnT(m-X)PP, X=NO2, Cl, OCH3, H, CH3) indichloromethane solvent by spectrophotometric technique. The isosbestic behavior is exhibited inthe region between 450 urn and 700 nm. The equilibrium constants K at 25 ℃ were determinedby the method of Rose-Drago. It was found that the stoichiometric number is unity for all 35.coordination reaction systems studied. A Hammett linear relationship exists between the ratioor equilibrium constant and the Hammett constant of substitutents on the phenyl ring ofporphyrin.