Oligothiophenes as liquid crystalline materials

Ponomarenko and Kirchmeyer synthesized didecyloUgothiophenes 2.49b by employing Kumada cross-coupling and/or Cu-catalyzed oxidative homocoupling reactions [112]. Due to the formation of high order in its LC phase, a,a -didecylquaterthiophene 2.49b (n = 2) is reported to be the most promising material for solution processable OFETs as compared with quinque- or sexithiophene derivatives 2.49b (n = 3, 4). 

Huisman et al. studied the LC behavior of semiconducting oligothiophenes 2.53 (n = 4-8) (Chart 1.12), which were substituted by polymerizable acrylate groups [119]. By using these materials for the fabrication of OFETs, it was observed that the use of polymer films resulted in a decrease in mobility by a factor of 10 compared with transistors made from the bisacrylate monomer. For example, the charge carrier mobility of 2.53 (n = 6) after polymerization was 6 x 10 cm V s compared with 4 x 10 cm V s before 

Cyano-substituted oligothiophene 2.57 (Chart 1.13) was prepared by Suzuki-type coupling reaction between 5-bromo-5 -cyanoterthiophene and the bis-boronic acid of the inner terphenyl building block 

Geerts et al. recently synthesized liquid crystalline oligothiophenes 2.61 (n = 1,2) (Chart 1.13) comprising two incompatible peripheral substituents, such as alkyl and perfluoroalkyl groups, which were attached to the core by Suzuki-type cross-coupling reactions [129]. Compound 2.61 (n = 1) formed a smectic A mesophase on cooling from 220 °C (isotropic liquid) to 200 °C, whereas 2.61 (n = 2) formed an insoluble material and no phase transitions were observed before decomposition at 250 °C. 

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Functional Oligothiophene-based Materials Nanoarchitectures and Applications 19 1.2.4 Oligothiophenes as liquid crystalline materials... 

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See also in sourсe #XX -- [ , , ]

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