Synthesis, Structures, and Photophysics of Polynuclear Silver(I) Thiolate and Silver(I) Thiocarboxylate Complexes with Dppm Ligands

Trinuclear silver(I) thiolate and silver(I) thiocarboxylate complexes [Ag3(μ-dppm)3(μn-SR)2](ClO4) [n = 2, R = C6H4Cl-4 (1) and C{O}Ph (2); n = 3, R = tBu (3)], pentanuclear silver(I) thiolate complex [Ag5(μ-dppm)4(μ3-SC6H4NO2-4)4](PF6) (4), and hexanuclear silver(I) thiolate complexes [Ag6(μ-dppm)4(μ3-SR)4]Y2 [Y = ClO4, R =C6H4CH3-4 (5) and C10H7 (2-naphthyl) (7); Y = PF6, R = C6H4OCH3-4(6)], were synthesized [dppm = bis(diphenylphosphanyl)methane] and their crystal structures as well as photophysical properties were studied. In the solid state at 77 K, trinuclear silver(I) thiolate and silver(I) thiocarboxylate complexes 1 and 2 exhibit luminescence at 470–523 nm, tentatively attributed to originate from the 3IL (intraligand) of thiolate or thiocarboxylate ligands, whereas hexanuclaer silver(I) thiolate complexes 5 and 7 produce dual emission, in which high-energy emission is tentatively attributed to come from the 3IL of thiolate ligands and low-energy emission is tentatively assigned to come from the admixture of metal···metal bond-to-ligand charge-transfer (MMLCT) and metal-centered (MC) excited states.