Synthesis and Structural Characterization of Luminescent Trinuclear Gold(I) Complexes with Dithiocarbamates

We have synthesized a series of trinuclear gold(I) complexes, namely, [Au3(μ-dpmp)(S2CNR2)nCl3-n] (n = 0−3; R = Me, CH2Ph), [Au3(μ-dpmp)(μ-S2CNR2)Cl](CF3SO3) (R = Me, CH2Ph), and [Au3(μ-dpmp)(μ-S2CNMe2)(C6F5)]X (X = Cl, CF3SO3), containing the triphosphine dpmp [bis(diphenylphosphinomethyl)phenylphosphine] and varying amounts of dithiocarbamate. NMR experiments show fluxional behavior in solution for most of these derivatives because several arrangements of the ligands are possible. The crystal structure of [(μ-dpmp)(AuCl)3] has been determined by X-ray diffraction studies; the molecule displays mirror symmetry and involves an angular arrangement of the gold atoms [Au−Au−Au 119.603(14)°, Au−Au 3.3709(4) Å]. We have studied the optical properties of these derivatives in the solid state, finding a red shift as a function of the dithiocarbamate number and, for some derivatives, wavelength-dependent emission spectra at low temperature.