Institut Parisien de Chimie Moléculaire, UMR CNRS 7201, UPMC Université Paris 06, 4 place Jussieu, 75252 Paris cedex 05, France.
Inorg Chem. 2011 Aug 15;50(16):7761-8. doi: 10.1021/ic200906b. Epub 2011 Jul 20.
Keggin and Dawson-type polyoxometalates (POMs) decorated by organometallic [cyclometalated ruthenium(II) polypyridine complex] or organic (pyrene) chromophores were prepared by postfunctionalization of hybrid disilylated POM platforms. The connection is made in a very efficient and modular way via Sonogashira coupling reactions, which provide a rigid linkage between the POM and the photoactive centers. Electronic properties have been inferred from electrochemical and photophysical studies and reflect poor electronic interactions between both partners. The presence of the POM leads to luminescence quenching of the chromophores, which was attributed to an intramolecular electron transfer from the chromophore to the POM. The rate of this process is much faster in the POM-pyrene than in the POM-Ru system. It depends on the driving force dictated by the redox potentials of both partners but also in the case of the POM-Ru system on the presence of the metallacycle, which acts as a molecular insulator and delays the intramolecular electron transfer. In the POM-Ru system, a comparative study of the luminescence quenching showed that the electron transfer is still more important in the covalently bonded hybrids than in systems where the POM and the ruthenium complexes are assembled via electrostatic interactions.
通过对杂化双硅烷基化 POM 平台进行后功能化，制备了 Keggin 和 Dawson 型多金属氧酸盐（POM），其被有机金属[环金属化钌（II）多吡啶配合物]或有机（芘）发色团修饰。这种连接是通过 Sonogashira 偶联反应以非常高效和模块化的方式进行的，该反应在 POM 和光活性中心之间提供了刚性连接。通过电化学和光物理研究推断出了电子性质，这些性质反映了两者之间的电子相互作用很差。POM 的存在导致发色团的发光猝灭，这归因于从发色团到 POM 的分子内电子转移。在 POM-芘中，该过程的速率比在 POM-Ru 体系中快得多。它取决于由两个配体的氧化还原电位决定的驱动力，但在 POM-Ru 体系中也取决于金属环的存在，后者作为分子绝缘体并延迟分子内电子转移。在 POM-Ru 体系中，对发光猝灭的比较研究表明，电子转移在共价键合的杂化物中比在通过静电相互作用组装 POM 和钌配合物的体系中更为重要。
