Thiophene oligomers and polymers

Likewise, a number of terthiophenes have been prepared and studied. For example, radical cations of the system 69 end-capped by bicyclo[2.2.2]octane units have been found to form centrally attracted bent 7t-dimers 06JA14470 . The trimer 70 has been included in a 

Much effort has been devoted to studies of thiophene oligomers and polymers, in particular in connection with development of new organic materials for electronic applications. Many of the synthetic approaches towards oligothiophenes rely on well-established methodology, such as metalations, halogen-metal exchange reactions, and transition metal catalyzed couplings. 

Additional studies have been devoted to oligothiophenes with electron-deficient fluorene-based groups 07JMA1055 , and a sexithiophene incorporating two fused TTF moieties 

The quinoid molecule 76 has been prepared by modification and oxidation of a suitable terthiophene precursor, and was utlized for solution-processible organic field effect transistors 07JA11684 . It should also be mentioned that such systems have been proposed to display diradical character in the singlet state, which appears to be more pronounced in longer molecules 07AG(E)9057 . 

Some fundamental aspects of polythiophene preparation and chemistry have been investigated. Solution processing of a polythiophene having ester groups has been performed, which after ester cleavage and decarboxylation gave new access to the parent thiophene polymer 07MAC6012 . The mechanism of the photoinduced polymerization of thiophene 

There has also been considerable activity in the field of copolymers containing thiophene moieties. For example, the copolymer 86 has been shown to self-assemble providing a lamellar superstructure, and was also demonstrated as a material for field effect transistors 

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Much work has been directed towards the synthesis of thiophene oligomers and polymers. This is due to the current interest in research on conducting polymers and molecular electronics (92CRV711). Two main approaches have been used for making such polymers (i) chemical (e.g. FeCl3) or electrochemical oxidation of monomeric thiophenes and (ii) transition metal-catalyzed cross-coupling reactions. 

The XPS Cls and S2p core-level lineshapes for the thiophene oligomers, thiophene polymers and alkyl-substituted thiophene polymers are well documented in the literature [117,123—126]. Table 3.4 summarizes the Cl s, S2p BE values, their linewidths (full width at half maximum, FWHM) and the S/C atomic ratios for several thiophene oligomers and polymers [117]. In general, the a and p carbons in thiophene polymers with a BE separation of only 0.34 eV cannot be resolved from the main Cls component. Two other minor Cls components located at above 2.6 eV and 5.2 eV above the main peak have been assigned to the shake-up structures. The S2p core-level spectrum is curve-fitted with two components with BEs at about 163.8 and 165.5 eV, corresponding to the respective spin-orbit split doublets (S2p3/2 and S2pi/2). An n transition shake-up structure is also discernible at... 

Table 3.4. Cls and S2p energy values (eV), spectral linewidths (FWHW) and S/C atomic ratios for several thiophene oligomers and polymers. (Reprinted with permission from ref 117, Am. Inst. Phys.)...

No other NLO devices are reported so far, although a lot of work has been devoted to the study of the third-order optical nonlinearities of thiophene oligomers and polymers [323] (compare Section 5.2). 

Silicon-containing thiophene oligomers and polymers synthesis, characterization and properties... 

Halothiophenes are crucial starting materials for various industrially important thiophene derivatives, including thiophene oligomers and polymers. 

Other systems, such as polydiacetylenes, and also polyphthalocyanines, have been examined recent investigations on thiophene oligomers and polymers, in forms of thin films, are in progress. 

The light-emitting properties of thiophene oligomers and polymers have recently been reviewed and the structural modifications for the tuning of the emission properties of these materials analyzed and discussed in detail [28]. 

L. Yang, J. K. Feng, A.-M. Ren, Stmctural, electronic and optical properties of a series of oligofluorene-thiophene oligomers and polymers, THEOCHEM, 758, 29-39 (2006). 

Silicon-containing Thiophene Oligomers and Polymers Synthesis, Characterization and Properties... 

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