Structures and Chemical Bonding of B5O7 +/0/- with a Hexagonal B3O3 Ring†.

This work aims to illustrate the influence of a single electron on the bonding properties and geometric structure of a benzene-like cluster, using B5O7 +/0/- as an exemplar. The inherent electron deficiency of boron dictates not only the rich structural variety of boron oxide clusters but also their unique electronic characteristics and unconventional bonding schemes. The discovery of cyclic boron oxide clusters has facilitated the study of their unique structures and bonding properties. We report a study of the bonding properties of B5O7 +/0/- clusters. The B5O7 + clusters exhibit a GM structure consisting of a boroxol core and two terminal OBO groups. The neutral B5O7 and anionic B5O7 - clusters are similar in structure, consisting of a boroxol core and three terminal ligands: a terminal boronyl group and an oxygen group and a terminal OBO group. In contrast to the B5O7 + and B5O7, a single electron completely reverses the potential energy surface of this system. All three structures have the heteroatomic ring B3O3 as their key structural. The terminal OBO ligand also has a double 3c-4e high valent π-bond.