Improved Synthesis of Bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF): π-Donor for Synthetic Metals

Abstract

2,5,7,9-Tetrathiabicyclo[4.3.0)]non-1(6)-en-8-thione (3) is prepared in increased yield by isolating the intermediate 4,5-dimercapto-1,3-dithiole-2-thione disodium salt (2) which undergoes efficient ring-closure with 1,2-dibromoethane. Quantitative oxidation of 3 with mercuric acetate to 2,5,7,9-tetrathiabicyclo [4.3.0]non-1(6)-en-8-one (4) followed by coupling with triethyl phosphite yields bis(ethylenedithio) tetrathiafulvalene (BEDT-TTF) in high overall yield.