Zinc Metallacarborane Chemistry

This work presents a new family of zincacarborane complexes synthesized from ZnMe₂ and [C2B9H13], using neutral two-electron donor ligands: N-heterocyclic carbenes (NHCs) yield the first closo-12-vertex half-sandwich zincocenes, [(NHC)Zn(C₂B₉H₁₁)] (1–3), while bulkier NHCs form slipped bis-dicarbollide salts (4–5). Us of pyridine leads to a macropolyhedral dimer (6) with a planar {Zn₂B₂} motif, and triphenylphosphine gives a V-shaped η³-borallyl complex (7). Structures have been confirmed by single-crystal X-ray diffraction and NMR spectroscopy. Computational studies (DFT and QTAIM) show predominantly ionic Zn–dicarbollide bonding with notable polar covalent character. Apparent Zn···Zn interactions are weak electrostatic contacts, and metal-ligand bonding is exclusively to boron atoms. Together, these findings broaden the structural and electronic landscape of zincacarboranes, challenge assumptions about d¹⁰ metal–carborane bonding, and offer a new platform for exploring group 12 metallacarborane reactivity.