ABSTRACT
Bis- and tris-fused π-electron donors composed of extended tetrathiafulvalene with anthraquinoid spacers (4 and 5) were successfully synthesized. X-ray structure analysis of tetrakis(methylthio)-5 (5a) revealed that the molecule adopted a transoid-cisoid conformation. The cyclic voltammogram of 4a is composed of two pairs of two-electron redox waves, while the cyclic voltammogram of tetrakis(hexylthio) derivative 5b consists of one pair of four-electron redox waves and one pair of two-electron redox waves, respectively. Spectroelectrochemistry of 4a and 1H NMR spectrum of a 4b salt revealed that two positive charges in 42+ are distributed mainly on one TTFAQ (9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene) moiety.
ABSTRACT
Derivatives of tris-fused TTF extended with two ethanediylidenes (5), tris- and pentakis-fused TTFs extended with two thiophene-2,5-diylidenes (6-9) were successfully synthesized. Cyclic voltammograms of the tetrakis(n-hexylthio) derivative of 5 and 7 (5d, 7d) consisted of two pairs of two-electron redox waves and two pairs of one-electron redox waves. On the other hand, four pairs of two-electron redox waves and two pairs of one-electron redox waves were observed for the tetrakis(n-hexylthio) derivative of 9 (9d). Coin-type cells using the bis(ethylenedithio) derivatives of 5 (5b), 6 (6b) and the tetrakis(methylthio) derivatives of 5 (5c) and 8 (8c) as positive electrode materials showed initial discharge capacities of 157-190 mAh g(-1) and initial energy densities of 535-680 mAh g(-1). The discharge capacities after 40 cycles were 64-86% of the initial discharge capacities.
