Study On Synthesis And Electrochemical Properties Of Silyl-Substituted Tetrathiafulvalene Derivatives

For more than three decades, much attention has been focused on the studies of tetrathiafulvalene (TTF) and its derivatives as organic molecular conductors on account of their good electron-donating properties. Recently, the studies on TTF derivatives have progressively been extended to the fields such as nonlinear optical materials, molecular electronic devices, Langmuir-Blodgett films, and macrocyclic and supramolecular chemistry.Among a variety of TTF derivatives, silyl-substituted TTF derivatives are seldom reported. However, the interaction between silyl group andπ-conjugation can increase the delocalization of the electons. From this viewpoint, the introduction of silyl group to TTF is of much significance.In this dissertation, CS2, sodium and other raw materials were used as starting materials to synthesize bis(1,3-dithiole-2-thione-4,5-dithiolate)zinc tetraethyl ammonium (TEA2[Zn(DMIT)2]). Five new silyl-substituted 1,3-dithiole-2-thiones(la-le) were synthesized from TEA2[Zn(DMIT)2]. Then, the thiones were easily converted to silyl-substituted 1,3-dithiole-2-ones(2a-2e) by treatment with mercuric acetate and acetic acid in dichloromethane. Homocoupling of (2a-2e) in triethyl phosphite afforded four new TTF detivatives(3a-3e). All new products were characterized by IR, H NMR, and 13C NMR spectra and MS. From the above products single crystals of compound la, 1d,2a,2d and 3a were obtained and X-ray single crystal structures of la,2a and 2d were measured.In addition, a chiral 1,3-dithiole-2-one compound 9 was synthesized with L-tartaric acid as the starting material through conservation, reduction, activation of hydroxyl groups and cyclization reaction. Crosscoupling of compound 9 and compound 2a in triethyl phosphite afforded a new chiral TTF derivative 10. Its structure was characterized by 1H NMR,13C NMR, MS and IR spectra.Finally, the electrochemical properties of the TTF derivatives were studied by cyclic voltametric determination in a triode work pool by using platinum electrode as the counter electrode, glassy carbon electrode as working electrode, and saturated calomel electrode (SCE) as reference electrode. The results showed that compound 3d exhibited Eox1=0.5891 V, Eox2= 0.9169 V, Ered1=0.5463 V, Ered2=0.8628 V. The values AE1 (42.8 mV) andΔE2 (54.1 mV) are less than 60 mV, so the redox reactions of 3d are reversible. While cyclic voltagram of compound 10 showed Eox1=0.7088 V, Eox2=1.0281 V, Ered1= 0.6168 V, Ered2=0.9198 V. The values AE, (92 mV) andΔE2 (108.3 mV) are greater than 60 mV, so the redox reactions of compound 10 are irreversible.