Synthesis of a vinylogue tetrathiafulvalene derivative and study of its charge transfer complex with TCNQF4

Abstract

Efficient synthesis of a vinylogue TTF derivative bearing four cyanoethylsulfanyl substituents, 9 is described. Cyclic voltammetry establishes that the novel compound shows good donor properties and a reduced on-site coulombic repulsion. Single crystal X-ray structure determination shows that the molecule has a planar structure of the conjugated moiety with a slipped π−π stacking organization in the crystal parallel to the crystallographic a axis. EPR, UV–vis and IR spectroscopies show that 9 forms a charge transfer complex with TCNQF4. EPR studies allow for the recognition of the 3:2 stoichiometry ratio between donor and acceptor while IR spectroscopy gave the estimation of the ionicity of the complex, which was found to be 0.31.