Prepn. of 4,4'-di:alkoxy-2,2'-bi:thiophene used for oxidn. stable polymers - by reacting 3-alkoxy:thiophene with metallo-organic cpd., then tri:methyl:chloro:silane using copper halide catalyst and acid hydrolysis

摘要

Prepn. of 4,4'-dialkoxy-2,2'-bithiophenes of formula (I) comprises reacting a 3-alkoxythiophene with a metalorganic cpd. then reacting with trimethylchlorosilane (TMCS) and metallising the trimethylsilyl-3-alkoxythiophene in position 5 - under the catalytic action of a copper (II) halide in 5,5'-ditrimethylsilyl-4,4- dialkoxy-2,2'-bithiophene then acid hydrolysis with cleavage of the trimethylsilyl gp. to give (I). In (I) R1 = opt branched 1-12C alkoxy or -O(CH2CH2O)nCH3; n= 1-4; and R2 = H, halogen or opt. branched 1-12C alkyl. Pref. the 3-alkoxythiophene is reacted with butyllithium, esp. in a stoichiometric ratio. USE/ADVANTAGE - Electropolymerisation or chemical oxidn. of (I) provides intrinsic electroconducting polymers with stability and capacity properties, e.g. esp. high optical transmission. Polymerisation of (I) (alkoxy = methoxy) gives high positive charge per thiophene-units. Polymers from it, have better oxidn. stability than the 3,3'-derivs.