Direct Observation of Photoinduced Bent Nitrosyl Excited-State Complexes

详细信息    查看全文

• 作者：Karma R. Sawyer ; Ryan P. Steele ; Elizabeth A. Glascoe ; James F. Cahoon ; Jacob P. Schlegel ; Martin Head-Gordon ; Charles B. Harris
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：September 18, 2008
• 年：2008
• 卷：112
• 期：37
• 页码：8505-8514
• 全文大小：440K
• 年卷期：v.112,no.37(September 18, 2008)
• ISSN：1520-5215

文摘

Ground-state structures with side-on nitrosyl (η²-NO) and isonitrosyl (ON) ligands have been observed in a variety of transition-metal complexes. In contrast, excited-state structures with bent-NO ligands have been proposed for years but never directly observed. Here, we use picosecond time-resolved infrared spectroscopy and density functional theory (DFT) modeling to study the photochemistry of Co(CO)₃(NO), a model transition-metal−NO compound. Surprisingly, we have observed no evidence for ON and η²-NO structural isomers, but we have observed two bent-NO complexes. DFT modeling of the ground- and excited-state potentials indicates that the bent-NO complexes correspond to triplet excited states. Photolysis of Co(CO)₃(NO) with a 400-nm pump pulse leads to population of a manifold of excited states which decay to form an excited-state triplet bent-NO complex within 1 ps. This structure relaxes to the ground triplet state in ca. 350 ps to form a second bent-NO structure.