摘要
用光度法测定了Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)原卟啉Ⅸ二甲酯(PP)配合物与轴向配体吡啶(Py)反应的化学平衡常数及产物分子的组成比,解释了实验结果,并探讨了Py轴向配位对上述金属卟啉配合物的紫外-可见光谱的影响。
The equilibrium constants and complexing ratios of the reactions between Co (Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ) and Cd(Ⅱ) protoporphyrin Ⅸ dimethyl ester (PP) complexes and axial ligand pyridine (Py) were determined by spectrophotometric method. Ni(Ⅱ) PP formed hexacoordinate complex with Py while the other four formed pentacoordinate complexes. The equilibrium constants of Co(Ⅱ), Zn(Ⅱ) and Cd(Ⅱ) PP(Py)s are much larger than of Cu(Ⅱ) PP(Py) and Ni(Ⅱ) PP(Py)_2. All these and the wavelength shifts in their UV-VIS absorption bands after axial ligation of Py can by explained by the repulsion of the d_(z^2) orbitals of the central ion on Py, the nonbonding repulsion of Py on the nitrogen atoms on the porphyrin ring and that Py altered the degree of 'core expansion' of the porphyrin ring and affected the energy of dπ orbitals which resulted in the wavelength displacements.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
1992年第2期33-37,共5页
Spectroscopy and Spectral Analysis
基金
This work was supported by the Foundation of National Science of the Chinese Academy of Sicences.
关键词
金属
卟啉
配合物
吡啶
轴向配位
Metalloporphyrin, Ultraviolet-visible spectra, Pyridine, Axial ligation
