Structure and Dynamics of the Cr(CO)3 Complexes of Triquinacene and Dimethylenecyclobutene by Hartree−Fock and Density Functional Methods

Combined perturbation MO, ab initio, and experimental investigations are employed in the study of (dimethylenecyclobutene)chromium tricarbonyl and triquinacenechromium tricarbonyl. Reasonable structural trends are obtained from a variety of computational methods; however, hybrid HF/DFT methods using sufficiently large basis sets offer the most accurate results in comparison to experiment. Although substantial barriers to rotation about the metal−arene bond are predicted for both, neither barrier is high enough to restrict the dynamics to the degree where atropisomerism at the laboratory time scale would be possible.