Theoretical Studies of Inorganic and Organometallic Reaction Mechanisms. 11. Migratory Insertion of Coordinated Nitric Oxide into Cobalt−Carbon Bonds

Autor:	Shuqiang Niu, Michael B. Hall
Rok vydání:	1997
Předmět:	Reaction mechanism Migratory insertion Ab initio chemistry.chemical_element General Chemistry Photochemistry Biochemistry Endothermic process Catalysis Crystallography Colloid and Surface Chemistry Cyclopentadienyl complex chemistry Density functional theory Molecular orbital Cobalt
Zdroj:	Journal of the American Chemical Society. 119:3077-3086
ISSN:	1520-5126 0002-7863
Popis:	The migratory insertion reaction of NO into the Co−CH3 σ-bond in the cobalt cyclopentadienyl complex CpCo(NO)(CH3) (2), both with and without the assistance of an incoming ligand (PH3, 1), has been studied using ab initio molecular orbital and density functional theory (DFT) methods. The insertion without PH3 association (Mechanism I) occurs with an activation energy of 10−20 kcal/mol, and the intermediate, CpCoN(O)CH3 (3a), forms with an endothermicity of 8−17 kcal/mol at the DFT-B3LYP and coupled cluster with singles and doubles (CCSD) levels of theory. The overall reaction to the product, CpCoN(O)CH3(PH3) (5b), was exothermic by −10 to −16 kcal/mol depending on the level of theory. An alternative mechanism II which begins with PH3 association and NO bending is endothermic by 16−18 kcal/mol and is immediately followed by a NO insertion barrier of 19−34 kcal/mol for an overall barrier of 35−52 kcal/mol. Therefore, Mechanism I is the favored pathway. This result is in very good agreement with the kinetic ...
Databáze:	OpenAIRE
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