Zinc Metallacarborane Chemistry

This work presents a new family of zincacarborane complexes synthesized from ZnMe₂ and [C₂B₉H₁₃], using neutral two-electron donor ligands: <i>N</i>-heterocyclic carbenes (NHCs) yield the first <i>closo</i>-12-vertex half-sandwich zincocenes, [(NHC)Zn(C₂B₉H₁₁)] (<b>1</b>-<b>3</b>), while bulkier NHCs form slipped bis-dicarbollide salts (<b>4</b>-<b>5</b>). Use of pyridine leads to the macropolyhedral dimer (<b>6</b>) with a planar {Zn₂B₂} motif, and triphenylphosphine gives a V-shaped η³-borallyl complex (<b>7</b>). 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.