Thiophene-Functionalized TTF pi-Electron Donors as Potential Precursors to Conducting Polymers and Organic Metals: Synthesis, Properties, Structure, and Electropolymerization Studies.

The synthesis and physical properties of a series of novel thiophene-substituted TTF electron donors (6a-d) are described. The cyclic voltammograms of 6a-d exhibited two reversible one-electron redox waves, characteristic of TTF derivatives. Electropolymerization studies on compound 6a in nitrobenzene indicate that no polymer formed on the working electrode, but a blue-colored intermediate was observed diffusing away from the electrode. In addition, the single-crystal X-ray structure of compound 6d indicates that the central five-membered C(3)S(2) rings are buckled and the ethylenedithiolo fragment adopts a twisted chair conformation. The pendant thiophene moieties are highly flexible, and short intermolecular interactions of 3.49 Å (S.S) and 3.45 Å (S.C) exist in the unit cell, resulting in the formation of a chain structure along the c-axis.