ELECTRICAL AND SPECTRAL PROPERTIES OF SOME BIS(OXAPROPYLENEDITHIO)TETRATHIAFULVALENE (BOPDT-TTF) SALTS

Three new organic charge transfer salts formed by the organic donor bi s(oxapropylenedithio)tetrathiafulvalene (BOPDT-TTF or OTT) and CIO4, B rO2 and Brl(2) anions have been synthesised, these crystals are semico nductors, sigma(dc)(300 K) being equal to 0.12, 10 and 5 x 10(-6) S cm (-1) for the salts with CIO4, BrO2, Brl(2) anions, respectively. The e lectrical conductivity is of activated type (BrO2 and Brl(2) salts) or is fitted well with the variable-range hopping model (CIO4 salt). Roo m temperature powder absorption spectra within the frequency range 400 -40,000 cm(-1) have been measured, From the position of charge transfe r bands it results that Coulomb interactions in BOPDT-TTF salts are st ronger than in other analogous compounds. The FT-NIR Raman spectrum of neutral BOPDT-TTF in the region of C=C stretching has also been studi ed.