1,3‐Bis(tricyanoborane)imidazoline‐2‐ylidenate Anion—A Ditopic Dianionic N‐Heterocyclic Carbene Ligand
Ludwig Zapf, Udo Radius, Maik Finze
Abstract
Abstract The 1,3‐bis(tricyanoborane)imidazolate anion 1 was obtained in high yield from lithium imidazolate and B(CN) 3 −pyridine adduct. Anion 1 is chemically very robust and thus allowed the isolation of the corresponding H 5 O 2 + salt. Furthermore, monoanion 1 served as starting species for the novel dianionic N‐heterocyclic carbene (NHC), 1,3‐bis(tricyanoborane)imidazoline‐2‐ylidenate anion 3 that acts as ditopic ligand via the carbene center and the cyano groups at boron. First reactions of this new NHC 3 with methyl iodide, elemental selenium, and [Ni(CO) 4 ] led to the methylated imidazolate ion 4 , the dianionic selenium adduct 5 , and the dianionic nickel tricarbonyl complex 6 . These NHC derivatives provide a first insight into the electronic and steric properties of the dianionic NHC 3 . Especially the combination of properties, such as double negative charge, different coordination sites, large buried volume and good σ‐donor and π‐acceptor ability, make NHC 3 a unique and promising ligand and building block.