Talotta Francesco, Heully Jean-Louis, Alary Fabienne, Dixon Isabelle M, González Leticia, Boggio-Pasqua Martial
Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université Toulouse 3 , 118 route de Narbonne, 31062 Toulouse, France.
Institut für Theoretische Chemie, Fakultät für Chemie, Universität Wien , Währinger Strasse 17, 1090 Vienna, Austria.
J Chem Theory Comput. 2017 Dec 12;13(12):6120-6130. doi: 10.1021/acs.jctc.7b00982. Epub 2017 Nov 28.
The N → O linkage photoisomerization mechanism in a ruthenium nitrosyl complex, [RuCl(NO)(py)], for which a quasicomplete photoconversion between the stable nitrosyl (N-bonded) and metastable isonitrosyl (O-bonded) isomers has been observed under continuous irradiation of the crystal at 473 nm ( Cormary et al. Acta Cryst. B 2009 , 65 , 612 - 623 ), is investigated using multiconfigurational second-order perturbation theory (CASPT2). The results support efficient intersystem crossing pathways from the initially excited singlet states to the lowest triplet excited state of metal-to-ligand charge transfer character (MLCT). The topology of the involved potential energy surfaces corroborates a complex sequential two-photon photoisomerization mechanism involving nonadiabatic processes in agreement with experimental observations and previous density functional theory calculations.
在一种钌亚硝酰配合物[RuCl(NO)(py)]中，N→O键光异构化机制已被研究。在473nm波长的晶体连续照射下，已观察到稳定的亚硝酰（N键合）异构体和亚稳的异亚硝酰（O键合）异构体之间几乎完全的光转化（Cormary等人，《Acta Cryst. B》2009年，65卷，612 - 623页）。使用多组态二阶微扰理论（CASPT2）对此进行了研究。结果支持了从最初激发的单重态到具有金属-配体电荷转移特性（MLCT）的最低三重激发态的有效系间窜越途径。所涉及的势能面拓扑结构证实了一种复杂的连续双光子光异构化机制，该机制涉及非绝热过程，这与实验观察结果和先前的密度泛函理论计算结果一致。
