Coordination chemistry of novel diatomic ligands of the main group

Boron Monfluoride (BF) is a simple, 10-valence electron diatomic molecule that is isoelectronic to carbon monoxide (CO). Unlike carbon monoxide however, BF is not a stable entity under ambient conditions, which punctuates an inherent dissimilarity in their electronic structures. Due to its instability as a free species, coordination complexes of BF, wherein the diatomic molecule is stabilized by binding to a transition metal center, have been highly desirable – yet elusive – targets for synthesis for many decades. Recently, we reported with first example of the terminal coordination of BF to iron in a coordination complex supported by two encumbering m-terphenyl isocyanide ligands. In this presentation, a detailed picture of the electronic structure of metal-coordinated BF is disclosed. In addition, important aspects of the influence of BF on the electronic structure of the metal center is discussed and contrasted with that of CO and other 10-valence electron diatomics, such as N₂ and [CN]^–. Also presented are systematic studies into the reactivity of BF as a coordinated ligand. Theoretical calculations have predicted that BF should be an exceptionally electrophilic ligand when bound to a metal. Reactions with nucleophilic substrates are disclosed that aim to elucidate this behavior, while also demonstrating reactivity aspects of BF that have not been previously considered. A highlight of these studies is the transformation of BF into other, highly unusual, main-group diatomic ligands. In addition, the preparation of heavier-element BF analogues is presented.