15min:

D. E. WOON AND T. H. DUNNING JR., Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801.

A structure was recently reported by Flory et al. for methyl zinc hydride, HZnCH₃, a molecule that may be formed via the direct insertion of Zn into one of the CH bonds of methane. The experiments were not able to demonstrate the formation pathway conclusively. The structures, bond energies, and other properties of HZnCH₃, ZnH, and ZnCH₃ were determined with high level coupled-cluster theory and multireference configuration interaction calculations in order to better understand the nature of the chemistry of HZnCH₃. The Zn--H and Zn--C bonds in HZnCH₃(X¹A₁) were found to be formed through recoupling the 4s² pair of Zn(¹S) in a manner that is very similar to the bonding in HBeCH₃ and other compounds where the 2s² pair of Be is recoupled. Various formation pathways were characterized, such as the analogous family of exchange reactions H~+~CH₄ CH₄~+~H, Zn~+~CH₄ ZnCH₃~+~H, and Be~+~CH₄ BeCH₃~+~H. Direct insertion may involve an intersystem crossing from the Zn(³P)~+~CH₄ triplet surface to the singlet surface, which has been explored.