聚合物配位体结构对钴卟啉氧结合性能的影响

Effect of structure of polymer ligands on oxygen-bindingproperties of cobaltporphyrin complexes

研究了4-乙烯基咪唑和1-甲基-4-乙烯基咪唑单体及其与甲基丙烯酸辛酯共聚物的合成与表征,以及共聚物与钴卟啉(CoP)络合物的氧结合性能.甲基丙烯酸辛酯-co-4-乙烯基咪唑共聚物(PO4I m)和甲基丙烯酸辛酯-co-1-甲基-4-乙烯基咪唑共聚物(POM4I m)的相对分子质量和乙烯基咪唑含量分别由GPC和元素分析法测定.PO4I m或POM4I m中的咪唑基与CoP配位,得到CoP络合物,其具有可逆的氧结合特性,氧结合平衡曲线服从Langmuir行为,并得到其与氧结合亲和力(p50).发现PO4I m-CoP络合物的氧结合亲和力大于POM4I m-CoP络合物,原因在于,PO4I m中4-乙烯基咪唑与甲基丙烯酸辛酯结构单元间形成了氢键.

Synthesis and characteristics of 4-vinylimdazole, 1-methyl-4-vinylimdazole, and their copolymers with octyl methacrylate, and the oxygen binding properties of cobahporphyrin （COP） complexes with vinylimdazole copolymers were studied. The molecular mass and vinylimidazole content of poly （ octyl methacrylate-co-4-vinylimidazole） （PO4Im） and poly （ octyl methacrylate-co-1-methyl-4- vinylimidazole） （POM4Im） were determined by GPC and elemental analysis, respectively. PO4Im or POM4Im and CoP in dichloromethane solution were mixed to complex the imidazolyl residue of copolymers with the fifth coordination site of CoP to get CoP complexes. CoP complex displayed a reversible change in the UV-visible absorption spectrum from the deoxy form to the oxygen-binding one with an isosbestic point, in response to the partial oxygen pressure of the atmosphere. The oxygen-binding equilibrium curves of CoP complexes obeyed Langmuir isotherm, to give the oxygen-binding affinity P50. The oxygenbinding affinity of PO4Im-CoP complex was larger than that of POM4Im-CoP complex. It was assumed that hydrogen bond formed in PO4Im improved the oxygen-binding affinity of the CoP complex. The binding and dissociation rate constants of oxygen to and from CoP complexes were large, which indicates a very rapid oxygen-binding.