Unprecedented Luminescent Heteropolynuclear Aggregates with Gold Thiolates as Building Blocks

The reaction of [AuCl(P–N)], in which P–N represents a heterofunctional phosphine ligand, with pentafluorothiophenol, HSC6F5, gives the thiolate gold derivatives [Au(SC6F5)(P–N)] (P–N = PPh2py (1), PPh2CH2CH2py (2), or PPhpy2 (3)). Complex [Au(SC6F5)(PPh2py)] (1) reacts with [Au(OTf)(PPh2py)] in a 1:1 or 1:2 molar ratio to afford the di- or trinuclear species [Au2(μ-SC6F5)(PPh2py)2]OTf (4) and [Au3(μ3-SC6F5)(PPh2py)3](OTf)2 (5), with the thiolate acting as a doubly or triply bridging ligand. The reactivity of the mononuclear compounds [Au(SC6F5)(P–N)] toward silver or copper salts in different ratios has been investigated. Thus, the treatment of [Au(SC6F5)(P–N)] with Ag(OTf) or [Cu(NCMe)4]PF6 in a 1:1 molar ratio gives complexes of stoichiometry [AuAg(OTf)(μ-SC6F5)(P–N)] (P–N = PPh2py (6), PPh2CH2CH2py (7), or PPhpy2 (8)) or [AuCu(μ-SC6F5)(P–N)(NCMe)]PF6 (P–N = PPh2py (9), PPh2CH2CH2py (10), or PPhpy2 (11)). These complexes crystallize as dimers and display different coordination modes of the silver or copper center, depending on the present functionalized phosphine ligand. The treatment of [Au(SC6F5)(PPh2py)] with silver and copper compounds in other molar ratios has been carried out. In a 2:1 ratio, the complexes [Au2M(μ-SC6F5)2(μ-PPh2py)2]X (M = Ag, X = OTf (12); M = Cu, X = PF6 (13)) are obtained. The same reaction in a 4:3 molar ratio affords the species [Au4M2(μ-SC6F5)3(μ-PPh2py)4]X3 (M = Ag, X = OTf (14); M = Cu, X = PF6 (15)). The crystal structures of some of these complexes reveal different interactions among the metallic d10 centers. The complexes display dual emission. The band at higher energy has been attributed to intraligand (IL) transitions, and the one at lower energy has been assigned to a ligand to metal (LM) charge transfer process. The latter emission is modulated by the heterometal (silver or copper).