Synthesis, photophysical properties, and molecular aggregation of gold(I) complexes containing carbon-donor ligands

Abstract

A series of gold(I) complexes with N-heterocyclic carbene (NHC) and acetylide ligands, namely [Au(NHC 1)(C≡CAr)] (NHC 1=1-(9-anthracenylmethyl)-3-(n)-butylimidazol-2-ylidene; 1b-1g), [Au(NHC 2)(C≡CAr)] (NHC 2=1,3-diethylimidazol-2- ylidene; 2b-2f) and [Au(C≡NAr) 2] + (C≡NAr=arylisocyanide; 3a-3f) have been synthesized. At room temperature, most of these gold(I) complexes are emissive in the solid state and in solutions with lifetimes in the nanosecond to submicrosecond regime. The emissions of complexes 1b-1g in solutions are assigned to 1π-π* excited states of the NHC ligand, while that of 2b-2f and 3a-3f are phosphorescent in nature. The intriguing solvatochromism of complex 3a was also investigated. Complexes 1b, 1d, 3a, and 3e aggregate into crystalline nanowires in freshly prepared THF/water dispersions. The X-ray crystallographic data reveal that 1b and 1d possess intermolecular π-π and C-H ... π interactions; while 3a was found to display intermolecular gold(I) ... π interactions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.