Abstract
The synthesis of novel unsymmetrically-substituted tetrathiafulvalene derivatives based on lithiation procedures is described. The disubstituted derivatives were synthesized as 1:1 cis/trans-isomeric mixtures, the compositions of which were established by 1H NMR and 13C NMR spectroscopy. The transition temperatures, refractive indices, birefringence, polarizability and order parameter of each of the mixtures were determined and the values are discussed in comparison with analogous compounds with the tetrathiafulvalene unit replaced by a 1,4-phenylene group. In addition, we describe the synthesis of a number of monosubstituted tetrathiafulvalene derivatives and their associated thermal properties. The isomeric compounds presented in this paper have exceptionally large values of polarizability anisotropy, as compared with their phenyl-containing counterparts.