Study of the effect of the phosphane bridging chain nature on the structural and photophysical properties of a series of gold(I) ethynylpyridine complexes

Alkynyl Au-I complexes of the type [Au(C CC5H4N)(PPh3)] (1) [Au-2(C CC5H4N)(2) (diphosphane)] [diphosphane = bis(diphenylphosphanyl)methane (2), bis(diphenylphosphanyl)isopropane] (3), bis(diphenylphosphanyl) acetylene (4), 1,2-bis(diphenylphosphanyl)ethane (5), 1,3-bis(diphenylphosphanyl)propane (6), 1,4-bis(diphenylphosphanyl)butane (7), 1,1'-bis(diphenylphosphanyl)ferrocene (8) and [Au-3(C C-C5H4N)(3)(triphos)] [triphos = 1,1,1-tris(diphenylphosphanyl-methyl)ethane] (9) were prepared by reaction of [Au(C CC5H4N)](n) with the suitable phosphane. Determination of the X-ray crystal structures of several compounds bearing different carbon backbones between the phosphorus atoms reveals the influence of the nature of the phosphane spacer on the establishment of intra and/or intermolecular gold-gold interactions. The absorption and emission properties of the complexes were analysed by taking into account the presence or absence of intermetallic interactions. Although UV/Vis spectra show differences for compounds with intramolecular Au-Au contacts, a conclusive trend was not observed in the emission behaviour. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).