New conducting radical salts based upon Keggin-type polyoxometalates and perylene

摘要

Three new radical salts,Per6[PMo_(12)O_(40)]] centre dot CH_2Cl_2 (1),Per_6[PMo_(12)O_(40)]] centre dot CH_3CN (2),and Per_9(NBu_4)4[SiW_(12_O_(40))_2 (3) (Per =perylene),have been synthesised and their electrical and magnetic properties characterised.These three salts are diamagnetic and they behave as semiconductors with room temperature conductivities of 69,3.6 and 0.85 S cm~(-1).While salt 2 presents hole-type conduction and 3 exhibits electron-dominated electrical transport properties,salt 1 shows at 150 K an abrupt change in the thermal dependence of the electrical conductivity and the Seebeck coefficient suggesting a phase transition.