NOVEL, HIGHLY CONDUCTING, AND SOLUBLE POLYMERS FROM ANODIC COUPLING OF ALKYL-SUBSTITUTED CYCLOPENTADITHIOPHENE MONOMERS

A series of 4-n-alkyl- and 4,4-di-n-alkyl-substituted cyclopentadithiophenes (C(n)CPDT and (Cn)2CPDT, n = 1, 3, 4, 6, 8, and 16) were synthesized and polymerized by anodic coupling in 0.1 M TEAP + AN. Electrochemistry, OR and electronic spectroscopies, elemental analysis, and in situ conductivity indicate that the polymers are oxidized to the conductive state (0.5 anion per monomeric unit) in two steps and in a single step for poly[C(n)CPDT] and poly[(C(n))2CPDT], respectively. The polymers are highly conductive (80-300 S/cm for poly[C(n)CPDT] and 2-40 S/cm for poly[(C(n))2CPDT]) and soluble in CHCl3 (degree of polymerization = 10-40 for poly[C16CPDT] and for poly[C4)2CPDT]). Absorption maxima, in the range 545-605 nm, are anomalously red shifted to 640 and 680 for poly[(C8)2CPDT] and poly[(C16)2CPDT].