Computational Studies of the Energetics and Reaction Pathways of Molecular Transformations of Benzoheterocycles on Triosmium Clusters

Abstract

Density functional theory (DFT) calculations have been performed on the series of complexes Os3(CO)10-n(μm-η2-(L-H))(μ-H) (L = benzoxazole (1), benzothiazole (2), quinoline (3), indoline (4), 1,2,3,4-tetrahydroquinoline (5); for 1−5, n = 0; m = 2; for 1‘−3‘, n = 1, m = 3) and on the precursors to these complexes, Os3(CO)10(CH3CN)2 and Os3(CO)12. The optimized geometry of the coordinately unsaturated 44e system Os3(CO)10 is used as a reference point for evaluating the relative binding energies of the heterocycles and the acetonitrile and carbonyl ligands. A discussion of how the intramolecular trans/cis isomerization of Os3(CO)10(CH3CN)2 relates to the reactivity of this complex with the heterocyclic ligand is presented. The relative binding energies of the benzoheterocycles provide insight into the relative stability of the intermediates involved in the subsequent formation of the μ3-nonacarbonyl derivatives Os3(CO)9(μ3-η2-(L-2H))(μ-H)2 (L = indoline (4‘), 1,2,3,4-tetrahydroquinoline (5‘)) from their μ-de...