Sato Shunsuke, Koike Kazuhide, Inoue Haruo, Ishitani Osamu
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1, E1-9, Meguro-ku, Tokyo 152-8551, Japan.
Photochem Photobiol Sci. 2007 Apr;6(4):454-61. doi: 10.1039/b613419j. Epub 2006 Nov 10.
We report the most efficient homogeneous photocatalyst yet for CO(2) reduction using a wide range of visible-light wavelength. We synthesized new Ru(II)-Re(I) binuclear complexes with 1,3-bis(4'-methyl-[2,2']bipyridinyl-4-yl)-propan-2-ol (bpyC3bpy) as a bridge ligand, specifically Ru-ReP(OEt)(3) and Ru-Repy where a P(OEt)(3) or pyridine ligand coordinates on the Re site. Their photocatalytic activities were compared with Ru-ReCl, which has a Cl(-) ligand on the Re site and has recently been reported as a much better photocatalyst (Phi = 0.12, TN(CO) = 160) than a 1:1 mixed system of the corresponding Ru(II) and Re(I) mononuclear complexes. The best photocatalyst was Ru-ReP(OEt)(3), for which Phi = 0.21 and TN(CO) = 232. A mechanistic study clearly showed that Ru-ReP(OEt)(3) is rapidly converted into the solvento complex Ru-ReSol, (Sol = DMF or TEOA) which is the actual photocatalyst. Although similar rapid ligand substitution occurs with other supramolecules, the pyridine and Cl(-) anions accelerate the decomposition of the supramolecular photocatalysts.
我们报道了迄今为止用于二氧化碳还原的最有效的均相光催化剂，它能利用广泛的可见光波长。我们合成了以1,3 - 双(4'-甲基 - [2,2']联吡啶基 - 4 - 基) - 丙 - 2 - 醇(bpyC3bpy)作为桥连配体的新型Ru(II) - Re(I)双核配合物，具体为[Ru - ReP(OEt)₃]³⁺和[Ru - Repy]³⁺，其中一个P(OEt)₃或吡啶配体在Re位点配位。将它们的光催化活性与[Ru - ReCl]²⁺进行了比较，[Ru - ReCl]²⁺在Re位点有一个Cl⁻配体，最近有报道称其作为光催化剂比相应的Ru(II)和Re(I)单核配合物的1:1混合体系要好得多(Φ = 0.12，TN(CO) = 160)。最佳光催化剂是[Ru - ReP(OEt)₃]³⁺，其Φ = 0.21，TN(CO) = 232。机理研究清楚地表明，[Ru - ReP(OEt)₃]³⁺会迅速转化为溶剂化配合物[Ru - ReSol]³⁺(Sol = DMF或TEOA)，而后者才是实际的光催化剂。尽管其他超分子也会发生类似的快速配体取代，但吡啶和Cl⁻阴离子会加速超分子光催化剂的分解。
