New global minima of 6-vertex dicarboranes: classical but unexpected

Abstract

Dicarboranes generally adopt global minimum predicted by the well-known Wade–Mingos rules, although one classical non-closo structure in the benzvalene form has long been pursued and later synthesized. Here we predicted two new non-closo global minima for 6-vertex dicarboranes (C₂B₄R₆), i.e., trigonal bipyramid (R = SH) and butterfly (R = Cl, NH₂, OH, F). The long expected classical benzvalene-like structure, however, is not the global minimum for any of the nine substituents.