The Chemistry of Gold–NHC Carbene Complexes

Abstract

Au-NHC chemistry has received much attention in the last 10 years, mainly due to straightforward synthetic routes to Au(I)-NHC complexes and their catalytic interest. Now Au-NHC complexes have been employed, not only as highly selective catalysts in directed organic synthetic strategies, but also as dynamic intermediates to promote constructive chemical steps at the metal active center. Some very recent examples have described the stabilization imparted by NHC which allows to isolate otherwise “unstable” intermediates, such as vinylgold derivatives. Another important property shown by Au-NHC complexes is their luminescence. The lower energy excitation and emission bands in some Au-NHCs are of suitable wavelengths for cellular distribution studies allowing to investigate the uptake and distribution in cancer cells using fluorescence confocal microscopy. The strong Au–carbene bonds also permit stable Au-NHC complexes immune to biologically important thiol groups, and thus Au-NHCs have also been found to have potential in medicinal and biochemical applications. Keywords: gold carbene complexes; gold catalysts; luminescence; medicinal and biochemical applications; N-Heterocyclic carbene