Synthesis of Thiophene Oligomers

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 reaction of 3-methoxythiophene is highly selective for C-2 and has been put to use for the synthesis of thiophene oligomers. The substitution of thiophenes, using aryl iodides, can also be carried out without interference from bromo substituents in the substrate. ... 

The synthesis and study of thiophene oligomers have attracted a great deal of attention for a number of years because of their activity against microorganisms, and recently because of their use as model compounds or... 

Two years later, the same research group published an alternative to the solvent-free method, since this method cannot be applied to the synthesis of insoluble thiophene oligomers such as sexithiophene [43]. Obviously, their insolubility prevents separation of the AI2O3 solid support. The effectiveness of PdCl2(dppf)/KF in solution phase was tested in the synthesis of soluble quinquethiophene from diiodoterthiophene and 2-thi-... 

The thiophene ring is a common building block for novel oligomeric and polymeric materials. The synthesis of monodisperse thiophene oligomers continues to be widely studied and the preparation of one class of oligomers, oligothienylenevinylenes <00CEJ1698,... 

Nagarajan R, Bruno FF, Samuelson LA, Kumar J (2004) Thiophene oligomer as a redox mediator for the biocatalytic synthesis of poly(3,4-ethylenedioxythiophene) [PEDOT]. Polym Prepr 45 195-196... 

It has been systematically unveiled that the re-conjugated systems incorporated with electron-withdrawing groups, especially perfluor-oalkyl groups, dramatically increase n-type character. In addition, the synthesis of the hexafluorocyclopenta[c]thiophene unit 354 and its oligomers has been reported (07OL2115). 

The synthesis of oligomers of thiophene-bearing fluorene derivatives as end cap has been reported (01JA9214 03CM1778). The terthienyl derivative showed an absorption band at 360 nm and emission bands at 570 and 608 nm. 

A. Facchetti, J. Letizia, M. H. Yoon, M. Mushrush, H. E. Katz, and T. J. Marks, Synthesis and characterization of diperfluorooctyl-substituted phenylene-thiophene oligomers... 

The solvent-free, microwave-assisted coupling of thienyl boronic acids and esters with thienyl bromides, using aluminum oxide as the solid support, served to rapidly check the reaction trends on changing times, temperature, catalyst, and base and easily optimize the experimental conditions to obtain the desired product in fair amounts. This procedure offers a novel, general, and very rapid route to the preparation of soluble thiophene oligomers. Quaterthiophene 265 was obtained in 6 min by reaction of 2-bromo-2,2 -bithiophene with bis(pinacolato)diborane(4) in 65% yield, whereas dithiophene 266 was obtained with 70% yield. The synthesis of new chiral 2,2 -bithiophenes also was reported. The detailed... 

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