The First Nickelacarborane with - Structure.

The first nickelacarborane with structure [10',11'-(Py)-3,9'-Ni(1,2-CBH)(7',8'-CBH)] was isolated from the reaction of nickel(IV) bis(dicarbollide) with pyridine. The molecular structure of this complex was determined by single crystal X-ray diffraction. The nickel atom is a common vertex for the -NiCB cluster and the -NCB cluster where it is located together with carbon atoms in the open NiCB pentagonal face. It is assumed that its formation proceeds through the nucleophile-induced removal of the B(6)H vertex followed by rearrangement of the forming 11-vertex cluster, which most likely proceeds through a sequence of closing and opening reactions.