アリールホウ素置換基を有する遷移金属錯体を利用した新規人工光合成系の創製

近年来，化石燃料能源短缺和环境污染已成为世界上亟待解决的两大问题。因此，太阳能作为一种可持续的能源，其利用已成为重要的研究课题之一。利用过渡金属配合物进行人工光合作用的化学方法在过去的几十年中一直在研究。特别地，具有芳香族二亚胺配体的三羰基铼（I）配合物[Re（CO）3LX]由于独特的光谱、光物理和光氧化还原性质而受到广泛关注。设计合成了四种新型的含一个或两个芳基硼烷电荷转移单元的三羰基双（I）配合物ReBphen/ReB 2 phen或ReBbpy/ReB 2bpy，并对其光谱性质进行了研究。对ReB 2 phen的物理性质进行了详细的研究，并对ReB 2 phen进行了X射线晶体学分析。结果表明，该配合物的结构与理论预测相符，其中的N（I）中心为近八面体配位构型，羰基配体为面取向排列.所有的配合物被证明是活性催化剂的CO2光还原，虽然其效率是依赖于复杂的性质。然而，与没有芳基硼烷单元的参考复合物相比，芳基硼烷复合物显示出较低的CO2形成周转数（TON）。

Recently, energy shortage from fossil fuels and pollution of the environments have been two largest issues to be solved in the world. Therefore, solar energy has been focused as a sustainable energy source and its utilization has been one of the important research topics. Chemical approaches toward artificial photosynthesis utilizing transition metal complexes have been studied in the past decades. In particular, a tricarbonyl rhenium(I) complex having an aromatic diimine ligand, [Re(CO)3LX], has been received extensive attention due to the unique spectroscopic, photophysical, and photoredox properties.Until now, four novel tricarbonyl rhenium(I) complexes having one or two arylborane charge transfer unit(s) ReBphen/ReB2phen or ReBbpy/ ReB2bpy were　designed/synthesized and the spectroscopic/photophysical properties were studied in detail.Then, X-ray crystallographic analysis of ReB2phen was conduceted. The results agree very well with the predicted structure of it, where the rhenium(I) center adopts a nearly octahedral coordination geometry and the carbonyl ligands are arranged in a facial orientation.Furthermore, the photocatalytic activities of them towards CO2 reduction were studied by photoirradiation of the complexes in DMF/TEOA solutions under CO2 gas atmosphere. All of the complexes were shown to be the active catalysts for CO2 photoreduction, although its efficiency was dependent on the nature of the complex. However, the arylborane complexes showed lower turnover numbers (TON) for CO2 formation compared to the reference complexes without arylborane units.