Architecture of crystalline polymers formed from the binuclear complexes XAuPh2P(CH2)(n)PPh2AuX through weak Au(I)center dot center dot center dot Au(I) interactions

A systematic study is reported of th-effects of weak attractive Au-I ... Au-I interactions on the solid state structures of six crystalline polymers from molecules of the type XAuPnPAuX, where X is iodide or chloride and PnP is Ph2P(CH2)(n)PPh2 with n=4-8. Crystallographic data for the six molecules IAuP4PAuI, IAuP5PAuI, IAuP6PAuI, ClAuP7PAuCl . CH3OH, IAuP8PAuI . CH2Cl2, and ClAuP8PAuCl . CH2Cl2 are presented. In each case, the complexes appear to be symmetrical monomeric species in solution, as shown by the simple, single-line P-31 NMR spectra. However, they form linear chains in the solid state with individual molecules connected through close Au ... Au contacts at each end of the molecule. These solids are analyzed in terms of the structures of individual molecules, geometries of Au ... Au interactions, methods of chain propagation, and relative orientations of individual chains. Only two types of propagation (pure translation and translation along a glide plane) of individual molecules are observed. The chains arrange themselves in three motifs: strands that run parallel, layers of strands that criss-cross, aid layers with an interwoven strand structure.