188686-92-2Relevant academic research and scientific papers
Highly conjugated poly(thiophene)s - Synthesis of regioregular 3-alkylthiophene polymers and 3-alkylthiophene/thiophene copolymers
Lere-Porte, Jean-Pierre,Moreau, Joel J. E.,Torreilles, Christophe
, p. 1249 - 1258 (2001)
Tributyltin derivatives of 2-bromo-3-octylthiophene and 5-bromo-4-octyl-2,2′-bi(thiophene) have been selectively prepared. Condensation reactions in the presence of Pd2(dba)3(CHCl3)/4 PPh3 led to high yields (ca. 90%) of regioregular poly(3-octylthiophene) (Mw = 21.4 × 104, Mw/Mn = 1.48) and poly[4-octylbi(thiophene)] (Mw = 3.8 × 104, Mw/Mn = 1.1). The regioregularity of the head-to-tail (HT) coupling has been determined by 1H NMR, which showed HT > 95% for poly(3-octylthiophene) and HT > 90% for the new poly[4-octylbi(thiophene)]. The conjugation properties of these materials have been characterized by FT-IR and UV/Vis spectroscopy. Compared to the corresponding random polymers, the absorption maxima of the new regular polymers are shifted to higher wavelengths (λmax = 448 and 466 nm, respectively). The mean conjugation length increases with increasing regioregularity of the coupling and with fewer substituents along the conjugated chain. The electroactive properties of the materials have also been studied. The new poly[4-octylbi(thiophene)] shows an oxidation peak at a low potential, and, compared to poly(3-octyl-thiophene), a reduction peak is also observed at a lower potential indicating a higher electron affinity. Both polymers exhibit reversible blue-red electrochromic behavior associated with the reversible redox properties.
