Bis(thioxo-diethylthiotetrathiafulvalenyl)ylidene, a New Donor Molecule with High Electron-Donating Ability Comparable to Tetrathiafulvalene

A new donor molecule, bis(thioxo-diethylthiotetrathiafulvalenyl)ylidene (1) was obtained by the iodine oxidation of bis (tetraethylammonium) bis(2,3-diethylthiotetrathiafulvalenyl-6,7-dithiolato) zinc complex (3). The molecular skeleton of 1 except for the four ethyl groups is almost planar and significant intramolecular S-S contact is present. The redox process of 1 is composed of four electron-transfer steps, of which the first step has almost the same redox potential (+0.40 V vs. Ag/AgCl) to that of tetrakis(ethylthio)tetrathiafulvalene (TET-TTF). Very interestingly, 1 exhibited longest-wavelength electronic absorptions near 1100 nm.