Synthesis and properties of hexyl-substituted oligothiophenes

Summary form only given. Recently, several researchers have prepared poly[3-(long alkyl)thiophenes] which have not only considerable conductivities ranging from I to 95 S/cm in oxidized states but also good solubility in usual solvents. NMR measurements of the poly(alkylthiophenes) showed that the polymers contained approximately 25 mole-% head-to-head configuration, indicating that the effective conjugation length is limited by twists of the polymer chain. Since chemically-prepared /spl alpha/-oligothiophenes that have well-defined structures, they are good models for studying charge storage in oxidized polymer chains and candidates for new functional materials. Thus far /spl alpha/-oligothiophenes from terthiophene to octithiophene have been prepared. Abderrahim et al. have prepared alkyl-substituted duodecithiophene containing 12 thiophene rings, but the position of the alkyl groups in the oligothiophene was uncertain. In this report, hexyl-substituted sexithiophene (1), novithiophene (2), duodecithiophene (3), and quindecithiophene (4) were prepared. 2, 3, and 4 that are purified satisfactorily are unknown. Their /spl pi/ - /spl pi/* transitions were compared with poly(alkylthiophene).