Synthesis, characterization and dc electrical conductivity of some oligmer mixed metal complexes

The synthesis of the oligomer metal complexes was systematically carried out in three steps starting from condensing terephthaldehyde with 2,5-diamino-3,4-dicyanothiophene in DMF. Dithienylenephenylene (TBT) produced was complexed with copper acetate to give di-TBT copper complex [Cu(TBT) 2]. This was complexed once more with a metal salt to give the 12-ring tri-metal oligomer M[Cu(TBT) 2] 2, where M is Co, Ni, or Cu. The presence of different transition metal ions allowed the comparison of the chemical and physical properties of the mixed metal complexes. The 12-ring mixed metal complexes were characterized through a comparative study of FTIR, electronic spectra and thermal analyses (TGA and DSC) in addition to the elemental analyses and metal content. A comparative study of the dc electrical conductivity in its intrinsic and 5% I 2-doped states with temperature variation in the range 300–500 K allowed tracing the action of the three different transition metals on the dc electrical conductivity of the mixed metal complexes.