Thermal Properties of Tetrakis(Alkyltelluro)Tetrathiafulvalene (TTeCn-TTF)

Thermal properties of tetrakis(alkyltelluro)tetrathiafulvalenes (TTeCn-TTF) are investigated using DSC technique. It is shown that combining tellurium substituted TTF skeleton with the alkyl chains of different length we got a variety of thermal properties due to a competition between the alkyl chains and the TTF moiety. This competition leads to a polymorphism and to an irregular dependence of the melting point as well as enthalpy and entropy of melting on the alkyl chain length between the carbon number n = 4 and 7. For the compounds with long alkyl chains (n > 6) the analysis of thermodynamic properties confirms the existence of the molecular fastener effect, i.e. fastening of the TTF skeletons and decreasing of the distances between them in the crystal structure by crystallization of the long alkyl chains.