Luminescent dinuclear gold complexes of bis(diphenylphosphano) acetylene

We have synthesized a series of dinuclear gold(I) derivatives with the diphosphane bis(diphenylphosphano)acetylene, namely [(AuX)(2)(mu-dppa)] (X=Cl, C6F5, SC6F5, S2CN(CH2Ph)(2)). X-ray structure determinations for the first three derivatives reveal a linear geometry for the gold centres. There are no intramolecular gold-gold interactions, although for X = Cl intermolecular gold(I)-gold(I) interactions of 3.0694(4) angstrom lead to an infinite twisted chain; the further presence of C-H (. . .) Cl contacts leads to a more complex three-dimensional structure. All the derivatives are luminescent in the solid state at low temperature in the range 455-593 nm: most of them are emissive at room temperature in the range 470-598 nm. We have also prepared the dinuclear gold(III) derivative [(AU(C6F5)(3))(2)(mu-dppa)]. Finally, we have prepared the derivative [(AuCl)(2)(mu-dppa)(3)], which forms a cage with two tetrahedrically coordinated gold(I) centres at the apical positions bridged by three rigid diphosphane ligands, with a helical twist of 26.2 degrees, and a gold-gold distance of 5.769 angstrom. The gold(III) and the four-coordinate gold(I) derivatives are not luminescent. (c) 2004 Elsevier B.V. All rights reserved.