Polythiophenes, properties chiroptical

Langeveld-Voss, B.M.W. et ah, Chiroptical properties of highly ordered di[(S)-2-methylbutoxy] substituted polythiophene and poly(p-phenylene vinylene), Synth. Met. 84, 611-614, 1997. 

Goto, H., E. Yashima, and Y. Okamoto. 2000. Unusual solvent effects on chiroptical properties of an optically active regioregular polythiophene in solution. Chirality 12 (5/6) 396-399. 

It was also observed that conjugated polymers that are also electrical conductors (see Chap. 10) exhibit optical activity that depends critically on their structural organization [78]. Thus, strong chiroptical properties can be obtained firom substituted polythiophene [79] (Chap. 10) with optically active side chains, especially when the monomers are coupled within the polymer in a regioregular head-to-tail fashion. Actually, optical activity of these materials is only found when the polymers are aggregated at low temperature, in poor solvent, or in solution cast films. This contrasts with other optically active polymers, like polypeptides, poly(l-alkynes) and polyisocyanates that show an optically active conformation of the main chain in the absence of supramolecular association. 

The polythiophene (PT) derivative is one of the most useful conjugated polymers, with extensive electrical, optical and chiroptical properties [71-82]. Following LC polyacetylene derivatives, many efforts have been made to synthesize LC-PT derivatives [22-27, 31-34]. Here, we describe the synthesis and properties of PT derivatives and their analogues of LC or FLC nature. 

Another interesting water-soluble polythiophene is 22, bearing a chiral amino acid side chain, which was prepared by Hjertberg, Inganas and co-workers by oxidative polymerization with FeClg. The chiroptical and sol-vatochromic properties of this optically active polymer are described in the later section entitled Chiroptical properties of optically active poly thiophenes. The synthesis of other, organic solvent-soluble chiral polythiophenes is discussed directly below. 

---