Planar or quasi-planar octa- and ennea-coordinate aluminum and gallium in boron rings

Abstract

An ab initio theoretical investigation has been performed on planar or quasi-planar octa- and ennea-coordinate Al and Ga centered in X@B8− and X@B9 (X=Al, Ga). These high symmetry molecular wheels all turned out to be true minima of the systems and σ+π double aromatic in nature, similar to the previously characterized D8h B@B8− both electronically and geometrically. Adiabatic and vertical detachment energies of the anions and the ionization potentials of the neutrals have been calculated to aid their eventual experimental identification.