Effects of the ethoxy and diethylamino substituent on the electrochemical and conducting properties of poly[(silanylene)oligothienylenes]

Polymers composed of alternating ethoxypropyl- oa diethylaminohexylsilanyle ne and oligo(2,5-thienylene) units, [(SiRX)(C4H2S)(m)](n) (3a-5a, R = Pr, X = OEt, m = 3-5; 5b, R = Hex, X = Et2N, m = 5) were synthesized and their p roperties were investigated in comparison with those of the diethylsilanyle ne analogs, [(SiEt2)(C4H2S)(m)](n) (3c-5c, m = 3-5). The UV and emission ba nds, and anodic peaks in cyclic voltammograms of polymers 3a-5a and 5b are at almost the same energies as those of the respective 3c-5c with the same number of m. However, polymers 3a-5a and 5b were found to be much more stab le toward electrochemical oxidation and reduction, as compared with 3c-5c w ith the same number of m. Polymers 3a-5a became conducting upon doping with FeCl3 with the conductivities in the order of 10(-2)-10(-1) S cm(-1), simi lar to the diethylsilanylene analogs 3c-5c. In contrast, polymer 5b exhibit ed highly conducting properties when doped with I-2, whose conductivity was determined to be 4.4 S cm(-1). Photoconducting properties of polymer 4a an d 4c are also described. (C) 2000 Published by Elsevier Science S.A. All ri ghts reserved.