K. Takahashi et al., CONJUGATION-EXTENDED TETRATHIAFULVALENE ANALOGS INVOLVING A CENTRAL AROMATIC 5-MEMBERED HETEROCYCLIC LINKING GROUP, Bulletin of the Chemical Society of Japan, 66(8), 1993, pp. 2330-2334
Conjugation-extended tetrathiafulvalene analogues, 2,5-bis(1,4-dithiaf
ulven-6-yl)thiophene (2a), 2,5-bis (methoxycarbonyl)-1,4-dithiafulven-
6-yl]thiophene, and 2,5-bis(1,4-dithiafulven-6-yl)furan, involving an
aromatic heterocyclic linking group have been synthesized by the Witti
g condensation reaction of 2,5-thiophene- and 2,5-furandicarbaldehydes
with 1,3-dithiol-2-ylidenetributylphosphorane and its 4,5-bis(methoxy
carbonyl) derivative. The electrochemical redox properties of these co
mpounds in solution have been investigated by cyclic voltammetry in or
der to evaluate the effect of the linking group on the donating abilit
y and the thermodynamic stability of the radical cations. Whereas the
radical cations are not so stable, complexes of 2a with 2,3-dichloro-5
, 6-dicyano-p-benzoquinone and iodine were found to show relatively hi
gh conductivities ((1.0-1.1) x 10(-3) S cm-1) on a compressed pellet a
t room temperature.