Influence of Backbone Fluorination in Regioregular Poly(3-alkyl-4-fluoro)thiophenes.

We report two strategies toward the synthesis of 3-alkyl-4-fluorothiophenes containing straight (hexyl and octyl) and branched (2-ethylhexyl) alkyl groups. We demonstrate that treatment of the dibrominated monomer with 1 equiv of alkyl Grignard reagent leads to the formation of a single regioisomer...

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Detalles Bibliográficos
Publicado en:	Journal of the American Chemical Society Vol. 137; no. 21; pp. 6866 - 6880
Autores principales:	Zhuping Fei, Boufflet, Pierre, Wood, Sebastian, Wade, Jessica, Moriarty, John, Gann, Eliot, Ratcliff, Erin L., McNeill, Christopher R., Sirringhaus, Henning, Ji-Seon Kim, Heeney, Martin
Formato:	Artículo
Publicado:	American Chemical Society 6/3/2015
Materias:	Fluorination Polythiophenes Density functional theory Alkyl compounds Polymerization Fluorine
Acceso en línea:	Ver este registro en EBSCOhost

Descripción
Sumario:	We report two strategies toward the synthesis of 3-alkyl-4-fluorothiophenes containing straight (hexyl and octyl) and branched (2-ethylhexyl) alkyl groups. We demonstrate that treatment of the dibrominated monomer with 1 equiv of alkyl Grignard reagent leads to the formation of a single regioisomer as a result of the pronounced directing effect of the fluorine group. Polymerization of the resulting species affords highly regioregular poly(3-alkyl-4-fluoro)- thiophenes. Comparison of their properties to those of the analogous non-fluorinated polymers shows that backbone fluorination leads to an increase in the polymer ionization potential without a significant change in optical band gap. Fluorination also results in an enhanced tendency to aggregate in solution, which is ascribed to a more co-planar backbone on the basis of Raman and DFT calculations. Average charge carrier mobilities in field-effect transistors are found to increase by up to a factor of 5 for the fluorinated polymers.