LAUSR

Abstract Neutral dinuclear gold(I) complexes having general formula [Au 2 Cl 2 (NHCP)] (NHCP = N -phosphanyl N -heterocyclic carbene) have been synthesized by two different synthetic procedures: i) transmetalation of the NHCP ligand from the corresponding dinuclear silver(I) complex; ii) deprotonation of the corresponding N -phosphanyl azolium/tetrahydropyrimidinium salt in the presence of the gold(I) precursor. Interestingly, although the silver complexes are invariably dinuclear dicationic species of formula [Ag 2 (NHCP) 2 ](OTf) 2 , both stoichiometries [Au 2 (NHCP) 2 ](OTf) 2 and [Au 2 Cl 2 (NHCP)] are potentially accessible with gold. Preference for either stoichiometry is dictated by the steric properties of the NHCP ligand as well as by a proper choice of the experimental conditions. On the other hand, preparation of copper(I) compounds with [Cu 2 Cl 2 (NHCP)] stoichiometry leads to product mixtures and has not led up to now to pure neutral compounds. Both the silver(I) and gold(I) complexes have been structurally characterized.