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

Ming Liu; Jan C Namyslo; Martin Nieger; Mika Polamo; Andreas Schmidt

doi:10.3762/bjoc.12.264

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

Beilstein J Org Chem. 2016 Dec 8:12:2673-2681. doi: 10.3762/bjoc.12.264. eCollection 2016.

Authors

Ming Liu¹, Jan C Namyslo¹, Martin Nieger², Mika Polamo², Andreas Schmidt¹

Affiliations

¹ Clausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany.
² University of Helsinki, Department of Chemistry, P.O. Box 55, FIN-00014 Helsinki, Finland.

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.

Keywords: anionic ligand; carbene tautomer; imidazol-2-ylidene; mesoionic compound; mesomeric betaine.