Catalytic Photooxidation of 4-Methoxybenzyl Alcohol with a Flavin-Zinc(<scp>II</scp>)-Cyclen Complex
作者:Radek Cibulka、Rudolf Vasold、Burkhard König
DOI:10.1002/chem.200400232
日期:2004.12.17
the flavin chromophore. This intramolecular process provides a much higher photooxidation efficiency, with quantum yields 30 times those of the comparable intermolecular process with a flavin chromophore without a binding site. For the reaction in buffered aqueous solution a quantum yield of Phi = 0.4 is observed. The turnover number in acetonitrile is increased (up to 20) by high benzyl alcohol concentrations
黄素锌(II)-周期素10包含共价连接的底物结合位点(锌(II)-环素)和生色团单元(黄素)。辐照后,化合物10在水中和乙腈中均有效地将4-甲氧基苄醇(11-OCH3)氧化为相应的苯甲醛。在空气的存在下,还原的黄素10-H2被再氧化,因此催化量10足以进行醇转化。氧化的机理是基于从配位的苯甲醇到黄素发色团的光诱导电子转移。这种分子内过程提供了更高的光氧化效率,其量子产率是具有黄素发色团而没有结合位点的分子间过程的量子产率的30倍。对于在缓冲水溶液中的反应,观察到Phi = 0.4的量子产率。高苯甲醇浓度可增加(最多20个)乙腈的周转次数。结果表明,发色团和合适的结合位点的共价组合可能导致光介体比经典的敏化剂分子更有效。