The First Carborane with a Distorted Cuboctahedral Structure

Abstract

As intermediates in the rearrangement of icosahedral 1,2-carboranes to give the corresponding 1,7-carboranes, carboranes with cuboctahedral structure were postulated by Lipscomb in the 1960s. The first example of this type of carborane, (CSiMe3)4B8H8, has now been prepared and characterized (X-ray crystal structure on the right). The stability of this compound and the minor deviation of the C4B8 frame from cuboctahedral geometry can be explained by the steric demand of the silyl substituents.