Synthesis of oligomeric 2,5-thienylenes; their u.v. spectra and oxidation potentials

Abstract

Oligomeric 2,5-thienylenes and 3-methyl-2,5-thienylenes have been synthesized by NiC12(dppp) (dppp = Ph2PCH2CH2CH2PPh2) coupling of Grignard compounds with the appropriate bromothiophene; U.V. spectra and oxidation potentials of the oligomers are dicussed in terms of coplanarity of the oligomeric species.

3D π‐Conjugated Oligothiophenes Based on Sterically Twisted Bithiophene Nodes

“…Table 1 lists the main UV-vis data of compounds 1 to 6 in methylene chloride solution. Comparison of the k max of compound 1 with that of quaterthiophene (390 nm) [11] reveals a 41 nm blue-shift consistent with the expected twisted structure of compound 1. The spectrum of compound 2 shows two maxima, at 346 and 400 nm, consistent with the coexistence of two different conjugation lengths (Fig.…”

“…In fact, comparison of the absorption maximum (k max ) of 7 to that of its position isomer 4,4′-dimethylbithiophene reveals a blueshift of k max from 312 to 270 nm, reflecting the large dihedral torsion angle generated by steric interactions between the methyl groups. [11] 5-Butylsulfanyl-2,2′-bithiophene (10) was prepared in 71 % yield by lithiation of bithiophene followed by reaction of the generated anion with sulphur and bromobutane. A second lithiation and reaction with tributyltin chloride gave 2-(tributylstannyl)-5′-butylsulfanyl)bithiophene (9), which was used without further purification.…”

“…Dimethylbithiophene 7 was synthesized by bromination of 3-methylthiophene by N-bromosuccinimide (NBS) followed by halogen lithium exchange and oxidative coupling using CuCl 2 . [11] Bromination of 7 with bromine in chloroform gave the tetrabromobithiophene 8 in 72 % yield (Scheme 3).…”

Role of substituent in electrooxidation of poly(1-substituted pyrrole) films

“…4 The electronic and steric structure of a substituent both contribute to the polymer -conjugation system. 5 However, the steric factor of n-alkyls is usually not so different from each other. 6 -8 On the other hand, the packing and orientation of polymer molecules in a solid are the important factors in understanding its electric conductivity.…”

Electrochemical Polymerization of 4,4-Dimethyl-2,2’-Bithiophene in Concentrated Polymer Liquid Crystal Solution

“…4,4'-Dimethyl-2,2'-bithiophene (4DMBT) is a thiophene derivative having alkyl group [1]- [14]. Electrochemical polymerization of conductive polymers gives high crystalline polymer film, but the control of the morphology is still a developmental issue.…”