An Isolable Anionic Gallabenzene: Synthesis and Characterization

An anionic gallabenzene was isolated and structurally characterized for the first time. The structure of gallabenzene in the crystal was isostructural with that of the recently reported anionic aluminabenzene. Structural parameters of the gallabenzene ring such as planar structure and unsaturated bond character without bond alternation were consistent with the structural criteria of the aromaticity. By DFT calculations of the gallabenzene, in addition to the presence of an ambiphilic contribution similar to the aluminum analogue, the plausible difference of the electronic structures between the galla- and aluminabenzenes due to the difference of electronegativity was also suggested.