From N-alkylimidazole ligands at a rhenium center: ring opening or formation of NHC complexes

J Am Chem Soc. 2008 Oct 15;130(41):13530-1. doi: 10.1021/ja805888f. Epub 2008 Sep 20.

Abstract

Cationic rhenium tricarbonyl complexes with three N-alkylimidazole ligands undergo deprotonation of the central CH group upon reaction with 1 equiv of KN(SiMe3)2. For the tris(N-methylimidazole) complex, the metal fragment shifts from N to C, leaving an NHC complex with a nonsubstituted N atom. For compounds with at least one N-mesitylimidazole ligand, the intramolecular attack of the deprotonated carbon onto the central carbon of an N-mesitylimidazole ligand results in ring opening of the latter.