Mononuclear copper(I) and binuclear silver(I) complexes of SPPh3 ligand: Synthesis, crystal structure, properties

Abstract

Two new complexes, [Cu(SPPh3)3]2(PF6)2 (1) and [Ag2(SPPh3)2](PF6)2 (2), were prepared from [M(CH3CN)4](PF6)] (M = Cu and Ag) and triphenylphosphine sulfide ligand (SPPh3). The complexes have been characterized by elemental analysis, and UV-Vis and IR spectroscopies. Single-crystal X-ray structure analyses reveals that complexes 1 and 2 can both be described as a planar triangular configuration. Complex 1 is mononuclear and shows two crystallographically independent and chemically identical [Cu(SPPh3)3]+ cations. In binuclear complex 2, the sulfur atoms in SPPh3 adopt two different coordination modes, namely monodentate and monoatomic bridging. Luminescence properties investigation in solid state show that complex 1 revealed only one emission band at 471 nm (λex = 310 nm), which may be attributed to metal-to-ligand charge-transfer [MLCT]. However, complex 2 had two emission peaks which attributed to π–π* and n–π* transitions. Electrochemical experiment illustrated the complexes 1 and 2 represent irreversible Cu+/Cu2+ or Ag+/Ag pairs, respectively. In vitro antioxidant tests showed that the complex 2 had significant antioxidant activity against hydroxyl radicals.