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 [C6H4(OCH2C=CAu)(2)](n) were prepared from AuCl(SMe2) and o-, m-, or p-bis(propargyloxy)benzene and then reacted with the diphosphines Ph2P(CH2)(n)PPh2 (n = 1-6) to give the corresponding ring complexes [C6H4(OCH2C=CAu)(2){mu -Ph2P(CH2)(n)PPh2}]. Alternatively, a two-step procedure in which the soluble isocyanide complex [p-C6H4(OCH2C=CAuCNtBu)(2)] was prepared, followed by displacement of the isocyanide ligands by the diphosphine, could be used. The complexes [m-C6H4(OCH2C=CAu)(2)(mu -Ph2PCH2PPh2)], [m-C6H4(OCH2C=CAu)(2){mu -Ph2P(CH2)(5)PPh2}], [p-C6H4(OCH2C=CAu)(2)(mu -Ph2P(CH2)(3)PPh2}] and [p-C6H4(OCH2C=CAu)(2){mu -Ph2P(CH2)(5)PPh2}] 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.