title: A theoretical investigation of photochemical reactions of an isolable silylene with benzene.
abstract: The mechanisms of photochemical insertion reactions are investigated theoretically using the model system, an isolable dialkylsilylene and benzene, using the CAS(10,10)/6-31G(d) and MP2-CAS-(10,10)/6-311++G(df,pd)//CAS(10,10)/6-31G(d) methods. The structures of the conical intersections, which play a key role in such photoinsertion reactions, are determined to provide a qualitative explanation of the reaction pathways. The model investigation demonstrates that the preferred reaction route for the isolable dialkylsilylene with benzene is as follows: reactants → Franck-Condon region → conical intersection → seven-membered-ring photoproduct. The theoretical findings suggest that the singlet excited dialkylsilylene should attack benzene in the perpendicular conformation, and that no silyl radicals should exist during these photoinsertion reactions. The results obtained allow a number of predictions to be made.
authors.affiliation: Department of Applied Chemistry, National Chiayi University, Chiayi 60004 (Taiwan); Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708 (Taiwan). midesu@mail.ncyu.edu.tw.
authors.forename: Ming-Der
authors.initials: MD
authors.lastname: Su
mesh_terms: D001554:Benzene / Q000737:chemistry*; D008962:Models, Theoretical; D008968:Molecular Conformation; D015394:Molecular Structure; D055668:Photochemical Processes; D012821:Silanes / Q000737:chemistry*
chemical_list: D012821:Silanes; D001554:Benzene
keywords: Group 14 elements; conical intersections; photochemistry; silicon; silylenes