Short Survey of the Chemical Reduction Behavior of the Base-Stabilized Iron Dichloroboryl Complexes [(η5-C5Me5)Fe(CO)2BCl2(LB)

Abstract

Stable boryl radicals are rare and often reactive species, usually requiring steric and/or electronic stabilization for their isolation. In this paper we describe attempts to use a sterically bulky and electron-rich metal fragment as a stabilizing group toward this end, using alternatively a phosphine, an N-heterocyclic carbene, and 3,5-lutidine as additional Lewis basic stabilization. Reduction of these complexes did not provide a stable radical as hoped, leading instead to decomposition or no reaction in the first two cases. For lutidine, an unusual dinuclear bis(boryl) product was obtained resulting from C–C coupling of the lutidine bases, suggesting the intermediacy of a reactive radical based partially on the lutidine ring. This possibility was explored computationally.