Mascarenhas Eric J, Fondell Mattis, Büchner Robby, Eckert Sebastian, Vaz da Cruz Vinicius, Föhlisch Alexander
Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany.
Institute of Physics and Astronomy, Universität Potsdam, 14476 Potsdam, Germany.
J Phys Chem Lett. 2024 Jan 11;15(1):241-247. doi: 10.1021/acs.jpclett.3c02775. Epub 2024 Jan 2.
Photosolvation is a type of ligand substitution reaction started by irradiation of a solution with light, triggering the replacement of a ligand with a molecule from the solvent. The excited state is created through many possible pathways. For the class of hexacyanides of groups 8 and 9 of the periodic table, irradiation in the ligand field band is followed by intersystem crossing to the lowest excited triplet state, which we propose to mediate the photoaquation reaction in this class of complexes. In this study, we present time-resolved X-ray absorption data showing indications of the triplet intermediate state in the cobalt(III) hexacyanide complex and we discuss general aspects of the photoaquation reaction in comparison with reported data on the isoelectronic iron(II) hexacyanide. Quantum chemical calculations are analyzed and suggest that the nature of the lowest excited triplet state in each complex can explain the drastically different rate of reactions observed.
光溶剂化是一种配体取代反应，通过用光照射溶液引发，促使配体被来自溶剂的分子取代。激发态可通过多种可能的途径产生。对于周期表第8族和第9族的六氰化物类，在配体场带中进行辐照后会发生系间窜越至最低激发三重态，我们认为该三重态介导了此类配合物中的光水合反应。在本研究中，我们展示了时间分辨X射线吸收数据，这些数据表明钴(III)六氰化物配合物中存在三重态中间体状态，并且我们将光水合反应的一般方面与关于等电子体铁(II)六氰化物的报道数据进行了比较。对量子化学计算进行了分析，结果表明每个配合物中最低激发三重态的性质可以解释所观察到的截然不同的反应速率。
