Silver(I) N-Heterocyclic Carbenes with Long N-Alkyl Chains

Silver(I) N-heterocyclic carbene complexes (Ag(I)−NHCs) with long N-alkyl side chains formulated as (a) ion pairs, (b) halide-bridged neutral complexes, and (c) disilver tetrahalide anion bridged tetranuclear complexes were obtained by the reaction of benzimidazolium and imidazolium halide salts with Ag 2 O. Interestingly, when excess Ag 2 O was used, Ag nanoparticles were formed along with Ag(I)−NHCs. Crystal structures of Ag(I)−NHC complexes including both long and short N-alkyl chains were determined. The diversity of the solid-state structures depended on the halide ions, chain length, carbene cores, and crystallization conditions. The Ag(I)−NHCs of long alkyl chains did not show liquid crystal properties but did so when mixed with their corresponding imidazolium salts. These organic−inorganic hybrids were good single-source precursors for silver nanomaterials.