Silver Complex of an N-Heterocyclic Carbene Ligand with Bulky Thiocarbamate Groups

The synthesis of a new N-heterocyclic carbene with bulky S-arylthiocarbamate substituents was devised from the condensation between 2-chloromethyl-4-methy-l, 6-[3,5-bis(trifluoromethyl)phenyl]-S-phenyl-N,N-dimethylthiocarbamate and imidazole, resulting in the proligand N,N'-bis[(2-S-(N '',N ''-dimethylthiocarbamoyl)-5-methyl) phenylmethyl] imidazolium iodide [H(S-carb)(2)NHC]I. This newly synthesized proligand was crystallographically characterized, thus confirming its identity; its stability was established in several solvents, resulting in air oxidation in methanolic solution, giving rise to the decomposition product N,N'-bis[(2-S-(N '',N ''-dimethyl-thiocarbamoyl)-5-methyl) phenylmethyl]-4,5-dimethoxyimidazolyl-2-one. Reaction of the proligand with silver oxide afforded the corresponding complex [(S-carb)(2)NHC]AgI, which was fully characterized by spectroscopic techniques.