title: Metal-assisted conversion of an N-ylide mesomeric betaine into its carbenic tautomer: generation of N-(fluoren-9-yl)imidazol-2-ylidene complexes.
abstract: Whereas the N-ylide mesomeric betaine 2, consisting of a fluorenyl anion directly attached to an imidazolium ring, is not in equilibrium with its putative free N-(fluoren-9-yl)imidazol-2-ylidene tautomer, its reaction with a metallic centre induces its interconversion to yield the corresponding monoligated N-heterocyclic carbene complex (Au(I) and Rh(I)). Deprotonation of 2 and coordination to the Rh(I)(COD) fragment allows the isolation of complex 7 displaying a rarely observed four-membered NHC-containing metallacycle and an enforced η(1)-fluorenyl ligand. Upon reaction with CpFe(CO)2I precursor, insertion of a carbonyl ligand into the Fe-fluorenyl bond occurs and yields the acyl-Fe complex 8.
authors.affiliation: CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse Cedex 4, France. vincent.cesar@lcc-toulouse.fr guy.lavigne@lcc-toulouse.fr.
authors.forename: Laure
authors.initials: L
authors.lastname: Benhamou
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bastin
authors.forename: Noël
authors.initials: N
authors.lastname: Lugan
authors.forename: Guy
authors.initials: G
authors.lastname: Lavigne
authors.forename: Vincent
authors.initials: V
authors.lastname: César