| Abstract: | The polymeric cobalt(II) porphyrin complexes were prepared from cobalt(II) protoporphyrin IX dimethyl ester(Co(II)P) and copolymers of 4-vinylpyridine and styrene(PSP), and their binding ability of molecular oxygen was studied in toluene solution. The five- and six-coordinate structure of CoP-PSP complexes were confirmed by esr spectra. The esr parameters for the CoP-PSP complexes were not affected by the molecular weight and the vinylpyridine-unit content of PSP-ligand. The 1:1 dioxygen-Co complex was reversibly formed when the solution of CoP-PSP was exposed to oxygen atmosphere at low temperature. While the visible spectra and esr parameters for the dioxygen complexes of CoP-PSP were the same as those of the CoP-pyridine complex, the equilibrium constant for the oxygen binding increased with the vinylpyridine-unit content of the PSP-ligand. The larger entropy change was observed for the oxygenation in the CoP-PSP system especially, of which the vinylpyridine-unit content was large. |
