Synthesis and properties of charge transfer complexes of copper substituted polyoxotungstate with Dawson Structure

Two new charge-transfer complexes, (DMAH)(10)[CuP2W17O62] . DMF . 2H(2)O and (DMAH)(14) [Cu2P2W16O62] have been prepared in aqueous solution from N,N'-dimethylaniline(DMA) and copper substituted polyoxotungstates with Dawson Structure, and characterized by elemental analysis, ICP, TG, IR, diffusion reflectance electronic spectra, polarography, and CV. The results indicate that the structure of anion has little change after the charge-transfer complexes are formed, but the characteristic vibrational bands have some red shift or blue shift. The charge transfer takes place under sunlight. There is a new absorption band at 625 nm in the solid reflectance electronic spectra of the complexes, it is ascribed to the IVCT (W (V)-->W(VI) band of the reduced anion [CuP2W17O62](10-). The conductivities at room temperature of title complexes are 3.6X10(-9) S . cm(-1) and 5.4X10(-9) S . cm(-1), respectively. Both of them are weak semiconductors.