Alkoxy-substituted bithiophenes

Alkoxy-substituted bithiophenes have also been successfully polymerized, using Cu(C104)2 as oxidant.50 As with related FeCl3 oxidations of alkyl-substituted bithiophenes,51 these dimeric substrates are easier to oxidize than the corresponding substituted thiophene monomers, due to their lower oxidation potentials. 

Alkoxy Substituted Thiophenes and Alkoxy Substituted Bithiophenes. The... 

PTs P-substituted by alkoxy and aryolxy groups have been synthesized from symmetrical bithiophenes 15 and 16. The position of the substituents proves to be crucial for the polymerization processes [64]. Bithiophene 15 substituted at the inner P-positions leads only to short-chain oligomers [64,65]. By contrast, substitution at the outer P-positions leads to a straightforward electropolymerization. As shown by electrochemical and theoretical studies, this latter mode of substitution contributes to enhance the density of unpaired electron at the coupling a-position [65]. 

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