Hydrogenation of B 12 0/− : A Planar-to-Icosahedral Structural Transition in B12H n 0/− (n = 1–6) Boron Hydride Clusters

Abstract

A systematic density functional theory and wave function theory investigation performed in this work reveals a planar-to-icosahedral structural transition between n = 4–5 in the partially hydrogenated B12Hn0/− clusters (n = 1–6) upon hydrogenation of all-boron B120/−. Coupled cluster calculations with triple excitations (CCSD(T)) indicate that a distorted icosahedral B12H6 cluster with C2 symmetry is overwhelmingly favored (by 35 kcal/mol) over the recently proposed perfectly planar borozene (D3h B12H6) (Szwacki et al., Nanoscale Res Lett 4:1085, 2009) which proves to be a high-lying local minimum. A similar 2D–3D structural transition occurs to the corresponding boron boronyl analogues of B12(BO)n with n –BO terminals. Detailed adaptive natural density partitioning (AdNDP) analyses reveal the bonding patterns of these quasi-planar or cage-like clusters which are characterized with delocalized σ and π molecular orbitals. The electron detachment energies of the concerned anions and excitation energies of the neutrals are also predicted to facilitate their future experimental characterizations.