3-alkoxy-4-methylthiophenes

An alternative, less sophisticated approach to regioregular substituted polythiophenes is the use of asymmetric 3,4-disubstituted thiophene monomers as substrates, resulting in the selective activation of either the 2- or 5- positions on the thiophene ring. Using this method, poly(3-alkoxy-4-methylthiophenes) with > 95% HT couplings have been prepared via FeCl3 oxidation.48 59... 

Appendix 2.D Survey of highly HT-regioregular poly(3-alkoxy-4-methylthiophene)s... 

Leclerc et al. first synthesized water-soluble biotinylated poly(3-alkoxy-4-methylthiophene)s to demonstrate their sensing ability. The polymer has a violet color in... 

Chen and Tsai prepared five 3-ether-substituted polythiophenes and poly(3-alkoxy-4-methylthiophene)s [82]. They measured absorption spectra in the FeCla-doped and undoped states, cyclic voltammograins and X-ray diffraction of these polymers. 

Remarkable progress was achieved, when the Hoechst group modified 3-alkoxythiophenes by additional substitution in the 4-position, especially by methyl groups (Figure 3.2) Table 3.1 summarizes the conductivity achievable with short-chain 3-alkoxy- and a few 3-alkoxy-4-methylthiophenes. ... 

But obviously the single oxygen atom in 3-alkoxy-4-methylthiophenes is not sufficient for an adequate mesomeric stabilization of the bipolaronic state in the doped polymer. For example, the poly-3-alkoxy-4-methylthiophenes described by Leclerc and Daoust (alkoxy=methoxy, n-butoxy) tend to be partially dedoped even by treatment with methanol, whereas poly-3,4-di-n-butoxythiophene... 

Figure 35 Changes in the color of solutions of a poly(3-alkoxy-4-methylthiophene) derivative induced by the addition of equimolar amounts of various anions. Reproduced with permission from Li, C. Numata, M. et al. Angew. Chem., Int. Ed. 2005, 44 (39), 6371-6374. ...

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