Synthesis of luminescent trinuclear gold(I) derivatives with a triphosphine and S-donor ligands

We have prepared a series of trinuclear gold(I) complexes containing bis(diphenylphosphinomethyl)phenylphosphine (dpmp) and several anionic S-donor ligands. The reaction of [(AuCl)3(μ-dpmp)] with potassium ethyl xanthate afforded the trinuclear gold(I) complexes [Au3Cl3−x(S2COEt)x(μ-dpmp)] (x=1, 2, 3). These complexes were readily transformed by reaction with silver triflate into [Au3Cl2−x(S2COEt)x(μ-dpmp)](CF3SO3) (x=1, 2). Treatment of [(AuCl)3(μ-dpmp)] with sodium 2-pyridinthiolate or potassium thiocyanate led to complexes [Au3Cl3−x(2-SC5H4N)x(μ-dpmp)] (x=1, 3) and [{Au(SCN)}3(μ-dpmp)]. The reaction of complex [Au3Cl2(S2COEt)(μ-dpmp)] with sodium dithiocarbamate yielded [Au3Cl(S2CNR2)(S2COEt)(μ-dpmp)] (R=Me, CH2Ph). We have studied the optical properties of these derivatives finding that most of them luminesce in the solid state at room temperature with emission maxima in the range 510–545, whilst at low temperature all are luminescent with emission maxima ranging from 480 to 545.