Cation-radical salts with organometallic gold anions.: X-ray structure of [TTFPh]2[Au(C6F5)2]

The combination of tetrathiafulvalene (TTF) and 4,4'-diphenyltetrathiafulvalene with organoaurate(I) and oganoaurate(III) salts, under a controlled current, affords crystalline solids containing organometallic anions: (TTFPh2)(2)[Au(C6F5)(2)], (TTFPh2) [Au(C6F3H2)(2)], (TTF) [Au(C6F5)Cl], (TTFPh2)(2.5) [AU(C6F5)(2)Cl-2], (TTF) [Au(C6F3H2)(2)Cl-2] and (TTFPh) [Au(C6F5)(2)I-2] which show moderate or low conductivities. (TTFPh2)(2)[Au(C6F5)(2)] has been studied by X-ray diffraction studies and shows stacks of TTFPh2 parallel to the x axis, with the planar [Au(C6F5)(2)](-) anions arranged in the interstices with their C-Au-C axes approximately perpendicular to the stacks. Its conductivity has been studied at different temperatures showing a semiconductor behaviour with an E-a=0.13 eV in the range of 300-200 K. Below 200 K the activation energy shows a gradual decrease until E-a = 0.012 at T = 77 K. (C) 1998 Elsevier Science S.A.