A theoretical study of three-centre M–H–C interactions

Abstract

The results of extended-Hückel calculations on some complexes of general formula [M(cycloalkenyl)L₃]ⁿ, which are known to possess agostic M–H–C interactions, are presented. The effects of changes in M and L are investigated and compared with experimental observations. It is found that the M–H–C interaction is best considered electronically as a highly bent open system rather than as a three-membered ring. Examination of the complex [Cr(C₈H₁₁)H(PF₃)₃] shows that it possesses several features in common with the alkenyl compounds, and hence should be considered as a weakly agostic system rather than a metal hydride.