Exploration of Synthetic Routes to the Sulfoxide and Sulfone Derivatives of Benzotrithiophenes

by Hall, Tiffany M.

The synthesis of new organic materials that have the potential to be utilized in a thermoelectric application are in demand because they are able to convert thermal energy directly into electrical energy. The “end-on” sulfoxide and sulfone derivatives of Benzo[1,2-c:3,4-c’:5,6-c’’]trithiophene 1 were synthesized for this reason. The “end-on” mode sulfoxide derivative 13 of Benzo[1,2-c:3,4-c’:5,6-c’’]trithiophene 1 was prepared by utilizing 3-Carboxypyridinium Chlorochromate (CPCC) 16 and AlCl3, as an oxidizing system. The ^1H NMR (DMSO-d6) spectrum displayed a singlet peak at 5.03 ppm, and the IR spectrum displayed an absorption at 1059.33cm-1, which confirmed its structure. The “end-on” mode sulfone derivative 14 was completed by a two step process: 1) oxidation of Benzo[1,2-c:3,4-c’:5,6-c’’] tris-(tetrahydrothiophene) 5 followed by 2) aromatization using DDQ in chlorobenzene. Verification of the compound’s structure was achieved via its ^1H NMR (DMSO-d6) spectrum that displayed a single peak at 6.5 ppm, which is in close approximation to the 6.64 ppm estimation.