Luminescent Binuclear Gold(I) Ring Complexes

Cyclic digold(I) complexes, containing bridging diphosphine and diacetylide ligands and with 15- to 22-membered rings, are reported. Oligomeric complexes [C 6 H 4 (OCH 2 C⋮CAu) 2 ] n were prepared from AuCl(SMe 2 ) and o-, m-, or p -bis(propargyloxy)benzene and then reacted with the diphosphines Ph 2 P(CH 2 ) n PPh 2 ( n = 1−6) to give the corresponding ring complexes [C 6 H 4 (OCH 2 C⋮CAu) 2 {μ-Ph 2 P(CH 2 ) n PPh 2 }]. Alternatively, a two-step procedure in which the soluble isocyanide complex [ p -C 6 H 4 (OCH 2 C⋮CAuCN t Bu) 2 ] was prepared, followed by displacement of the isocyanide ligands by the diphosphine, could be used. The complexes [ m -C 6 H 4 (OCH 2 C⋮CAu) 2 (μ-Ph 2 PCH 2 PPh 2 )], [ m -C 6 H 4 (OCH 2 C⋮CAu) 2 {μ-Ph 2 P(CH 2 ) 5 PPh 2 }], [ p -C 6 H 4 (OCH 2 C⋮CAu) 2 {μ-Ph 2 P(CH 2 ) 3 PPh 2 }], and [ p -C 6 H 4 (OCH 2 C⋮CAu) 2 {μ-Ph 2 P(CH 2 ) 5 PPh 2 }] have been characterized by X-ray structure determinations. The ring complexes are emissive at room temperature and may exhibit either red or blue shifts between solution and the solid state.