Structural study and electrical conductivity of salts based on functionalized TTF containing peripheral selenium atoms

Abstract

Five new substituted tetrathiafulvalene derivatives containing the acetoxyphenyl group as a side-chain have been synthesized using a Wittig-type condensation. Four of them contain peripheral selenium atoms. From cyclic voltammetry data, the electron donor abilities of the obtained compounds have been found to be similar to that of BEDT-TTF. The crystal structures of three of these new donors have been determined. A series of radical cation salts derived from these donors has been obtained by electrocrystallization; the electrical conductivity of these phases measured on compressed powder pellets range from 5 × 10⁻⁴ to 4 × 10⁻⁵ S cm⁻¹. Charge transfer complexes have also been chemically prepared by using TCNQ as an electron acceptor; the electrical conductivity of their compressed powders range from 0.3 to 0.5 S cm⁻¹. The crystal structure of one of these charge transfer complexes has been determined and shows that the donor and the acceptor entities form regular segregated stacks; its rather high conductivity, actually measured on powder, is in agreement with this structural feature.