Full Electron Delocalization across the Cluster in 1,12-bisBMes<sub>2</sub>-<i>p</i>-carborane Radical Anion
Lin Wu, Xinning Zhang, Michael Moos, Ivo Krummenacher, Maximilian Dietz, Arumugam Jayaraman, Rüdiger Bertermann, Qing Ye, Maik Finze, Michael Wenzel, Roland Mitrić, Christoph Lambert, Holger Braunschweig, Lei Ji
Abstract
Conjugation between three-dimensional (3D) carboranes and the attached substituents is commonly believed to be very weak. In this paper, we report that reducing 1,12-bis(BMes 2 )- p -carborane ( B 2 p Cab ) with one electron gives a radical anion with a centrosymmetric semiquinoidal structure. This radical anion shows extensive electron delocalization between the two boron centers over the p -carborane bridge due to the overlap of carborane lowest unoccupied molecular orbital (LUMO) and the BMes 2 LUMO. Unlike dianions of other C 2 B 10 H 12 carboranes, which rearrange to a nido -form, two-electron reduction of B 2 p Cab leads to a rearrangement into a basket-shaped intermediate.