Theoretical Studies on the Stabilities of Metallabenzynes

Abstract

Theoretical calculations at the B3LYP level of density functional theory have been carried out to study the stability of osmabenzyne complexes. Isodesmic reactions have been designed to analyze the ring strain and conjugation energies of the complexes. The ring strain energy was found to be small, primarily because of the relatively small angle of bending at the carbyne carbon. The conjugation energy is comparable to those of benzene and osmabenzene. The effect of substituents at the ring carbons on the stabilities has also been examined. Through molecular orbital analyses, we found that the effect of substituents on the energies of π orbitals in the six-membered ring play important roles in determining the relative stabilities.