From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

Abstract

The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl) borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol) imidazol-2-ylidene reacts with (triphenylphosphine) gold(I) chloride to give the cationic NHC complex [Au(NHC)(2)][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolate) imidazol-2-ylidene gives the complexes [K][Au(NHC-)(2)], [Rh(NHC-)(3)] and [Ni(NHC-)(2)], respectively. Results of four single crystal analyses are presented.