CyanobenzeneTTF-type donors; synthesis and characterization

Two cyanobenzeneTTF-type electron donors, which are also dithiolene ligand precursors, cyanobenzenedicyanoethylthiotetrathiafulvalene, (cbdc-TTF) and dicyanobenzenedicyanoethylthiotetrathiafulvalene, (dcbdc-TTF), were obtained through cross-coupling reactions with triethyl phosphite between 4,5-bis(2-cyanoethylthio)-1,3-dithiole-2-one and 4,cyanobenzene-1,3-dithiole-2-thione or dicyanobenzene-1,3-dithiole-2-thione, respectively. These reactions also yield 2,3,6,7-tetrakis(2-cyanoethylthio)-TTF and the corresponding symmetric cyanobenzene TTF derivatives dicyanodibenzenetetrathiafulvalene (dcdb-TTF) and tetracyanodibenzotetrathiafulvalene (TCN-DBTTF) resulting from the self-coupling reactions of the ketone and the thiones. Compound dcdb-TTF was also synthesized by homo-coupling reaction of the cyanobenzene-1,3-dithiole-2-ketone with triethyl phosphite. These compounds were characterized namely by single crystal X-ray diffraction and cyclic voltammetry.