Oligothiophenes alkyl-substituted

FIGURE 5.3.1 Chemical structure of alkyl-substituted oligothiophenes. 

Figure 11.5 Crystal structure of DMQtT (see Figure 11.1 for the structural formula) viewed along the a-axis. The broken lines indicate the nearest intermolecular contact between the methyl carbons. From S. Hotta and K. Waragai, Alkyl-substituted oligothiophenes crystallographic and spectroscopic studies of neutral and doped forms,]. Mater. Chem., 1(5), 835-842 (1991). Reproduced by permission of The Royal Society of Chemistry...

Figure 16.12 Chemical structure of various alkyl-substituted oligothiophenes...

Figure 8.15. Synthetic scheme of the alkyl-substituted oligothiophenes of dimer to hexamer. Reprinted with permission from Reference 76. Copyright 1993 VCH Verlagsgesellschaft.

The results for these alkyl-substituted oligothiophenes can be summarised as follows ... 

On the basis of these considerations, Hotta and Waragai [174] have studied absorption spectroscopy of the thin solid films of alkyl-substituted oligothiophenes (trimer to hexamer see Figure 8.14 for chemical structures) over near-UV to mid-IR regions. They have studied the absorption spectra of these materials which were taken in both neutral and doped states. The most outstanding feature that distinguishes the solid-state spectra from those taken in solution is that the former display a strong n-n absorption band in the oxidized... 

Absorption bands, 179 A.C. conductivity of polyacetylene, 29 Actuators, 137, 162, 458-459 Aged catalyst, 9 Alkoxypyrroles, 154 Alkyl-pyrroles, 154 A-alkyl-pyrroles, 154 Alkyl-substituted oligothiophenes, 328 Alkyl-substituted polyazines, 731 3-alkyl-substituted polythiophenes, 311 3-alkylthiophene, 272 Alkylthiophenes, 145, 154... 

The PIIR spectra of variously alkyl-substituted oligothiophenes give the following information ... 

In their series of regioirregular -alkyl substituted oligothiophenes (see section 3.2.2.1) Wynberg et al. also included a /3-alkylated undecithiophene 317 which was synthesized similarly to the oligomers by Stetter reaction and subsequent cyclization of the diketone with L.R. In this case, the terminal groups do practically not influence the properties in comparison to the, 3-alkylated undecithiophene 122. Conductivity, solubility, and absorptions are nearly identical [156]. 

Table 2. Recent data on the field effect mobility of unsubstituted and alkyl substituted oligothiophenes.

S. Hotta and K. Waragai, Alkyl-substituted oligothiophenes - crystallographic and spectroscopic studies of neutral and doped forms, J. Mater. Chem., 1991,1, 835. 

H. Akimichi, K. Waragai, S. Hotta, H. Kano and H. Sakati, Field-effect transistors using alkyl substituted oligothiophenes, Appl. Physl Lett., 1991,58, 1500. 

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