Department of Chemistry , University of North Carolina at Chapel Hill , Murray Hall 2202B , Chapel Hill , North Carolina 27599-3290 , United States.
Engineering of Molecular NanoSystems, Ecole Polytechnique de Bruxelles , Université libre de Bruxelles (ULB) , Avenue F.D. Roosevelt 50, CP165/64 , B-1050 Brussels , Belgium.
J Am Chem Soc. 2018 Jun 27;140(25):7799-7802. doi: 10.1021/jacs.8b04961. Epub 2018 Jun 19.
A "ter-ionic complex" composed of a tetracationic Ru(II) complex and two iodide ions was found to yield a covalent I-I bond upon visible light excitation in acetone solution. H NMR, visible absorption and DFT studies revealed that one iodide was associated with a ligand while the other was closer to the Ru metal center. Standard Stern-Volmer quenching of the excited state by iodide revealed upward curvature with a novel saturation at high concentrations. The data were fully consistent with a mechanism in which the Ru metal center in the excited state accepts an electron from iodide to form an iodine atom and, within 70 ns, that atom reacts with the iodide associated with the ligand to yield I. This rapid formation of an I-I bond was facilitated by the supramolecular assembly of the three reactant ions necessary for this ter-ionic reaction that is relevant to solar fuel production.
在丙酮溶液中，可见光激发后发现由一个四价阳离子钌（II）配合物和两个碘离子组成的“多离子络合物”形成了共价 I-I 键。核磁共振氢谱、可见吸收和 DFT 研究表明，一个碘离子与配体结合，而另一个碘离子更接近钌金属中心。用碘化物对激发态进行标准 Stern-Volmer 猝灭时，发现其曲率向上，在高浓度下出现新的饱和。这些数据完全符合一种机制，即在激发态的 Ru 金属中心从碘化物中接受一个电子，形成一个碘原子，然后在 70 ns 内，该原子与与配体结合的碘化物反应，生成 I。这种 I-I 键的快速形成是由形成多离子反应所需的三个反应离子的超分子组装所促进的，这种多离子反应与太阳能燃料的生产有关。
