SYNTHESIS AND CHARACTERIZATION OF TETRATHIAFULVALENE CHARGE-TRANSFER COMPOUNDS WITH IRON AND ANTIMONY HALIDES

The charge transfer compounds (TTF)4FeCl3.CH3OH, (TTF)4SbCl4 and (TTF)5(SbBr4)2-CH3COCH3 were prepared from reactions of the TTF (tetrathiafulvalene) and metal halides. The compounds were characterized by spectroscopic (UV, IR, EPR and XPS) methods, magnetic susceptibility and electrical conductivity measurements. The d.c electrical conductivities of the pressed pellets are in the order of 10(-1)-10(-3) Scm-1, which lies in the range of semiconductor region at room temperature. It means that the partially ionized TTF has stacked in low-dimensional chain in each compound. Spectroscopic properties also indicate that TTF molecules are partially ionized and charge transfer has occurred from (TTF)n to Fe(III) center in (TTF)4FeCl3.CH3OH whereas to the -SbX4- entity in (TTF)4SbCl4 and (TTF)5(SbBr4)2. CH3COCH3 The EPR g values are consistent with TTF radical formation and EPR linewidths suggest the delocalization of unpaired electrons along TTF stacks. A signal arised from metal (Fe and Sb) ions were not detected in EPR spectra, indicating that metal ion is in the diamagnetic state in each compound. The diamagnetic state was also examined by the magnetic susceptibility measurement. The magnetic properties reveal the significant interactiion between the TTF+ radical cations in the stacks. The oxidation state of metal ions was also investigated by XPS spectra.