Synthesis and thermal behaviour of α,α′-didecyloligothiophenes

Abstract

a,a'-Didecylquater-, -quinque-and -sexi-thiophenes were synthesized by Kumada cross-coupling and oxidative coupling reactions. For the former reaction Pd(dppf)Cl 2 was found to be a more efficient catalyst than the usually applied Ni(dppp)Cl 2 . Thermal behaviour of all new oligothiophenes was investigated by differential scanning calorimetry and polarizing optical microscopy. It was shown that all these compounds possess not only crystal phases but also high temperature ordered smectic mesophases and that the clearing point increases linearly with the number of conjugated thiophene rings. A degree of order in the crystal phase was estimated on the basis of thermodynamic data. The highest degree of order was proposed for a,a'-didecylquaterthiophene, which explains why the mobility of end-a,a'-capped quaterthiophenes in FET (field effect transistor) devices is comparable or sometimes better than those of corresponding quinque-and sexi-thiophene derivatives.

Air‐Operable, High‐Mobility Organic Transistors with Semifluorinated Side Chains and Unsubstituted Naphthalenetetracarboxylic Diimide Cores: High Mobility and Environmental and Bias Stress Stability from the Perfluorooctylpropyl Side Chain

“…In addition, there have been other correlations between thermodynamic data and crystallinity. [37][38][39] Even though we did not obtain DSC data from actual thin fi lms, the relatively large enthalpy change from the mesophase to the crystal phase in the cooling curve of 8-3-NTCDI suggests that either the crystalline phase has unusually strong intermolecular ordering or that the mesophase is unusually mobile, allowing for greater annealing out of defects during deposition on heated substrates. By analogy to a previously published study, we expect that the mesophases are layered (smectic) phases.…”

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

“…As found in the literature [11,26,[33][34][35][36][37] and described in our previous publication, [22] there are several oligothiophenes which show liquid crystalline properties. It is not too sur- Table 3 C 20 -br-lin…”

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

“…More recently, Kirchmeyer and co-workers reported on the large-scale synthesis of didecyl oligothiophenes from the appropriate thiophenes or bithiophenes by Ni-or Pd-catalyzed Kumada cross-coupling or Cu-catalyzed oxidative homocoupling. [11] This approach provides fair-to-excellent yields but requires a relatively high number of synthetic steps. The commercial availability of terthiophene 3 and quaterthiophene 4 prompted us to examine their direct one-step functionalization to give 1 and 2.…”