Reactions of a Borataalkene Ligand at Tantalocene Centers: Isonitrile Insertion into the B−C Bond of the [CH₂B(C₆F₅)₂] Ligand via the η¹ Bonding Mode

Abstract

Trapping of the tantalocene borataalkene complex Cp2Ta[CH2B(C6F5)2] with 2 equiv of cyclohexyl or benzyl isocyanide gives Ta(III) products where the metallocene fragment is ligated by an η3-1-azaallyl ligand incorporating an iminoacyl boryl fragment on the central carbon atom. This unique ligand assembly arises via reaction of the isocyanide reagent with the η1 form of the borataalkene ligand, demonstrating a new reactivity mode for this relatively unexplored class of boratahydrocarbon ligands.