Key Laboratory of Photochemical Conversion and Optoelectronic Materials, CAS-HKU Joint Laboratory on New Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Peking 100190, PR China.
Dalton Trans. 2012 Jul 21;41(27):8421-9. doi: 10.1039/c2dt30415e. Epub 2012 May 29.
A series of platinum(II) complexes bearing a chromophore-acceptor dyad obtained by reacting 4-(p-bromomethylphenyl)-6-phenyl-2,2'-bipyridine or 4'-(p-bromomethylphenyl)-2,2':6',2''-terpyridine with pyridine, 4-phenylpyridine, 4,4'-bipyridine, 1-methyl-4-(pyridin-4'-yl)pyridinium hexafluorophosphate respectively, were synthesized. Their photophysical properties, emission quenching studies by Pt nanoparticles and methyl viologen, electrochemical properties and photoinduced electron-transfer reactions in a photocatalytic hydrogen-generating system containing triethanolamine and colloidal Pt without an extra electron relay, were investigated. A comparison of the rates of hydrogen production for the two photocatalytic systems, one containing a metal-organic dyad and the other comprising a 1:1 mixture of the parental platinum(II) complexes and the corresponding electron relay, showed that intramolecular electron transfer improves the photocatalytic efficiency. Compared with cyclometalated platinum(II) complexes, the related platinum(II) terpyridyl complexes exhibited poor performance for photocatalytic hydrogen evolution. An investigation into the amount of hydrogen generated by three platinum(II) complexes containing cyclometalated ligands with methyl groups located on different phenyl rings revealed that the efficiency of hydrogen evolution was affected by a subtle change of functional group on ligand, and the hydrogen-generating efficiency in the presence or absence of methyl viologen is comparable, indicating electron transfer from the excited [Pt(C^N^N)] chromophore to colloidal Pt. (1)H NMR spectroscopy of the metal-organic dyads in an aqueous solution in the presence of excess triethanolamine revealed that the dyad with a viologen unit was unstable, and a chemical reaction in the compound occurred prior to irradiation by visible light under basic conditions.
一系列含有发色团-受体偶联物的铂(II)配合物，通过将 4-(对溴甲基苯基)-6-苯基-2,2'-联吡啶或 4'-(对溴甲基苯基)-2,2':6',2''-三联吡啶与吡啶、4-苯基吡啶、4,4'-联吡啶、1-甲基-4-(吡啶-4'-基)吡啶六氟磷酸盐反应得到。研究了它们的光物理性质、铂纳米粒子和甲基紫精的荧光猝灭研究、电化学性质以及在含有三乙醇胺和胶体铂的光催化产氢系统中的光诱导电子转移反应，无需额外的电子中继。比较了含有金属-有机偶联物和含有母体铂(II)配合物和相应电子中继物 1:1 混合物的两个光催化系统的产氢速率，表明分子内电子转移提高了光催化效率。与环金属化铂(II)配合物相比，相关的铂(II)三联吡啶配合物在光催化析氢方面表现不佳。对三种含有环金属化配体的铂(II)配合物的产氢量进行研究，这些配体的甲基位于不同的苯基环上，结果表明配体上官能团的细微变化会影响氢的生成效率，并且在存在或不存在甲基紫精的情况下产氢效率相当，表明电子从激发态[Pt(C^N^N)]发色团转移到胶体铂。在过量三乙醇胺存在下，金属有机偶联物在水溶液中的 1H NMR 光谱表明，带有紫精单元的偶联物不稳定，并且在碱性条件下可见光照射前，化合物中发生了化学反应。
