NEW COPPER COMPLEX WITH PI-CONJUGATED ELECTRICALLY CONDUCTIVE POLYMER CHELATING LIGAND, POLY(6,6'-DIALKYL-2,2'-BIPYRIDINE-5,5'-DIYL) - PREPARATION AND OPTICAL AND ELECTROCHEMICAL PROPERTIES OF THE COMPLEX

pi-Conjugated electrically conducting polymer chelate ligands, poly(6,6'-dimethyl-2,2'-bipyridine-5,5'-diyl) (P6MeBpy) and poly(6,6'-dihexyl-2,2'-bipyridine-5,5'-diyl) (P6HexBpy), react with [Cu(CH3CN)(4)]X (X=BF4, ClO4) to give the corresponding semiconductive copper(I) complexes. The P6HexBpy-CuBF4 complex exhibits an MLCT absorption at 469 nm (epsilon=3300 M(-1) cm(-1)). The cyclic voltammogram of a film of the P6HexBpy-CuBF4 complex laid on a Pt electrode shows reversible redox peaks with an E(0), value of 0.59 V versus Ag+/Ag due to a Cu(II)/(I) couple, whereas, in the reduction region, the film of the complex exhibits an electrochemically active cycle at E(0) of -1.84 V attributable to a Cu(I)/(0) couple. The redox process at -1.84 V is accompanied by a color change of the film from orange to dark red. These UV-Vis and electrochemical data of the P6HexBpy-CuBF4 complex are discussed by comparing them with data of monomeric model complexes, [Cu(bpy)(2)]BF4, [Cu(dmebpy)(2)]BF4 and [Cu(dhexbpy)(2)]BF4 (dmebpy=6,6'-dimethyl-2,2'-bipyridine; dhexbpy=6,6'-dihexyl-2,2'-bipyridine).