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.