SYNTHESIS OF SOME FUNCTIONALIZED ISOMERIC BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE (BEDT-TTF) AND DITHIOPHENETETRATHIAFULVALENE (DTTTF) PI-DONORS

The synthesis of some functionalised isomeric, symmetrical tetrathiafu lvalene derivatives containing 4,5-(ethylenedithio)-1,3-dithiole and 4 ,5-(propylenedithio)-1,3-dithiole units is described. These contain hy droxy, chloro and cyano functionalities (4, 6, 9 and 12). Interestingl y, attempted coupling of 4,5-bis(propargylthio)-1,3-dithiole-2-thione 13, to obtain the corresponding TTF, 14 afforded the novel thione, 5-m ethylthieno[2,3-d]-1,3-dithiole-2-thione 15. Self coupling of thione 1 5 in the presence of trimethyl phosphite afforded new functionalised d ithiophenetetrathiafulvalene 16. The X-ray crysal structures of 4,5-bi s(propargyldithio)-1,3-dithiole-2-thione 13 and 5-methylthieno[2,3-d]- 1,3-dithiole-2-thione 15 are described. (C) 1997 Elsevier Science Ltd.