Symmetrical and Nonsymmetrical Liquid Crystalline Oligothiophenes: Convenient Synthesis and Transition‐Temperature Engineering

Abstract

Two approaches to transition‐temperature engineering in liquid crystalline oligothiophenes are described: (i) substitution at the aromatic core with two identical branched alkyl chains and (ii) desymmetrization of the molecule with two alkyl substituents of different length or structure. Key steps in the synthesis of symmetrical and nonsymmetrical terthiophenes and quaterthiophenes involve Suzuki coupling and carbanion alkylation. A well‐adjusted balance between the π–π stacking of the aromatic core and the disorder caused by the peripheral alkyl chains is demonstrated to be important for the control of the thermotropic behavior of oligothiophene mesogens. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Low-power dihexylquaterthiophene-based thin film transistors for analog applications

“…5,6 Generally, these shortfalls, while hampering the rapid development of hybrid organicinorganic circuits, have fostered the introduction of highly engineered gate dielectrics. 10 Here, we focus on the performance of DH4T transistors upon downscaling and nanoengineering of the gate insulator. In this context, experimental evidence has been accumulated for the existence of fast charge transport in liquid crystalline materials including thiophene derivatives by time-of-flight experiments.…”

Aggregation Phenomena of Long α‐ and α,ω‐Substituted Oligothiophenes – the Effect of Branched vs. Linear End‐Groups

“…A similar strategic approach based on lithiation and metal-catalysed coupling reactions was reported recently. [24] In accordance with the synthetic strategy above the oligomers from the dimer 38ab to the hexamer 42ab were obtained by Stille-type coupling. The monoalkylated and monostannylated oligomers were treated with the corresponding monobrominated derivatives which were synthesised by bromination of the monoalkylated oligomers 7, 9, 11, and 13 with NBS according to the literature [25] (Scheme 3).…”

Unraveling Unprecedented Charge Carrier Mobility through Structure Property Relationship of Four Isomers of Didodecyl[1]benzothieno[3,2‐b][1]benzothiophene

“…Almost all the isomers possess only one phase transition except 2 for which a smectic A phase (SmA) is observed prior to melting, as a result of its rod-like molecular shape. [ 25 ] With its herringbone motif, the crystal of 2 melts at 117.4 °C. This value is higher than the melting point of the other materials, ranging from 86 to 103 °C.…”