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合成了以三联吡啶锇Os(II)配合物为光敏剂的PS-Fe2S2型模拟铁氢化酶分子光催化剂1a及其分子间光催化模型化合物1b和2,研究了配合物1a和1b的吸收光谱,发光光谱及电化学性质.配合物1a和1b均表现出三联吡啶锇Os(II)配合物的MLCT吸收峰;与不含Fe2S2基团的配合物1b相比,在配合物1a中三联吡啶锇Os(II)配合物单元的发光被明显猝灭,猝灭程度为92%.而在同样浓度下,配合物1b与2组成的分子间体系中三联吡啶锇Os(II)配合物的发光仅被猝灭了4%.通过Rehm-Weller方程计算得出由三联吡啶锇Os(II)配合物单元到Fe2S2活性中心的光致电子转移自由能为正,表明分子内1a和分子间1b+2体系均不能发生光致电子转移,体系发光猝灭的原因是三联吡啶锇Os(II)配合物3MLCT激发态与铁氢化酶模拟活性中心Fe2S2的能量转移.
PS-Fe2S2-type mimic enzyme molecule 1a and its intermolecular photocatalytic model compounds 1b and 2 were synthesized by using osmium (Ⅲ) bipyridyl complexes as photosensitizers. The absorption spectra of complexes 1a and 1b , Luminescence spectra and electrochemical properties.The complexes 1a and 1b both show the MLCT absorption peak of the osmium bipyridyl Os (II) complex. Compared with the complex 1b without Fe2S2 group, The luminescence of osmium Os (II) complex was significantly quenched with a quenching rate of 92%, while at the same concentration, the luminescence of the osmium bipyridyl Os (II) complex in the intermolecular system of complexes 1b and 2 Only quenched by 4% .The calculated free energy of photoelectron transfer from the ternary bipyridine osmium (II) complex unit to the active center of Fe2S2 was calculated by the Rehm-Weller equation, indicating that intramolecular 1a and intermolecular 1b + 2 system can not occur photoinduced electron transfer. The reason for the luminescence quenching of the system is the energy transfer between the 3MLCT excited state of the osmium bipyridyl Os (II) complex and Fe2S2, an activity center of the iron-hydrogenase simulation.