Synthesis of a new extended π-donor with 1,4-oxathiane annulation

4,5;4′,5′-Bis(1,4-oxathiane-2,3-diyldithio)tetrathiafulval ene7 (TOET) is synthesised in four steps from 1,4-oxathiane. Compound 7 shows two reversible redox couples at 0.56 and 0.90 V vs. SCE. Analysis of NMR spectra combined with energy minimisation calculations indicated that at least three isomers of TOET should be present in solution. TOET forms a charge-transfer complex with TCNQ which shows a conductivity of 3×10 -3 S cm -1 .