Efficient synthesis of brominated tetrathiafulvalene (TTF) derivatives:: solid-state structure and electrochemical behaviour

An efficient synthesis is reported for 4,5-dibromo-[1,3]dithiole-2-thione (1) and 4-bromo-1,3-dithiole-2-thione (7) by bromination of lithiated vinylene trithiocarbonate. Compound 1 acts as a convenient precursor to a number of asymmetric electron donors. This is exemplified by the formation of 4,5-dibromo-4',5'-bis(2'-cyanoethylsulfanyl)TTF (3) by cross-coupling methodology and subsequent conversion into 4,5-dibromo-4',5'-ethylenedithioTTF (4) by reaction with caesium hydroxide and 1,2-dibromoethane. The new donor 4,5-dibromo4',5'-ethylenedithiodiselenadithiafulvalene (5) was prepared by cross-coupling of 1 and 4,5-ethylenedithio-1,3-diselenol-2-one (6). The X-ray structures of 3 and 5 are reported. (c) 2006 Elsevier Ltd. All rights reserved.