Synthesis, structure and luminescence of new dinuclear cyanido-bridged AgI–AuI one-dimensional coordination polymer

A new alternating chain compound consisting of gold(I) and silver(I) bridged by cyanides is reported. The Ag(I) ion is functionalized by 2 triphenyl phosphane ligands, resulting in the formula [Au(Ctriple bond; length of mdashN)2(PPh3)2Ag]n. The compound has been prepared by room temperature reaction of triphenyl phosphane with the cyanide salts of silver(I) and gold(I). The product has been characterized and its single crystal X-ray structure was determined. In the molecular structure of the complex, the Au(I) centers exhibit the expected linear, two-coordinate geometry with C-bound cyanides, whereas the Ag(I) centers adopt a tetrahedral geometry in a AgN2P2 chromophore. The shortest hetero intermetallic separation distance is 4.94(7) Å. No aurophilic interactions are observed, but only the non-conventional Csingle bondH…Au hydrogen interactions are present. Upon excitation at 325 nm, a quite intense luminescence at 475 nm, assigned on the basis of DFT calculations to MMLCT, is observed, which amounts to ca. 10% of the luminescence intensity of the best known luminescent compounds.