Bis- and Tris-fused Tetrathiafulvalenes Extended with Anthracene-9,10-diylidene

Bis- and tris-fused π-electron donors composed of extended tetrathiafulvalene with anthraquinoid spacers (<b>4</b> and <b>5</b>) were successfully synthesized. X-ray structure analysis of tetrakis­(methylthio)-<b>5</b> (<b>5a</b>) revealed that the molecule adopted a <i>transoid–cisoid</i> conformation. The cyclic voltammogram of <b>4a</b> is composed of two pairs of two-electron redox waves, while the cyclic voltammogram of tetrakis­(hexylthio) derivative <b>5b</b> consists of one pair of four-electron redox waves and one pair of two-electron redox waves, respectively. Spectroelectrochemistry of <b>4a</b> and ¹H NMR spectrum of a <b>4b</b> salt revealed that two positive charges in <b>4</b>²⁺ are distributed mainly on one TTFAQ (9,10-bis­(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene) moiety