Acid-Catalyzed Polycondensation of 2-Acetoxymethyl-3,4-dimethylthiophene. Access to a Novel Poly(thienylene methine) with Alternating Aromatic- and Quinoid-like Structures

Abstract

This paper reports the synthesis of a novel soluble poly(thienylene methylene) by a straightforward process based on the methanesulfonic acid-catalyzed self-condensation of 2-acetoxymethyl-3,4-dimethylthiophene. These macromolecules were found to generate in situ conjugated sequences consisting of thiophene and exounsaturated 2,5-dihydrothiophene moieties. The kinetics of these polycondensations, in which both the temperature and the monomer-to-catalyst molar ratio were varied, were followed by HPLC, as regards the rate of monomer consumption, and by GPC, as regards the evolution of the molecular weight of the growing chains. The ensuing polymers were characterized by FTIR, 1 H NMR, UV-vis spectroscopy, DSC, and TGA. † This contribution is dedicated to the fond memory of our dear friend and colleague Giovanna Costa, who died while this investigation was in progress.

Functionalization of poly(bis‐thiophene methine)s via facile C–C bulk polymerization and their application as chemosensors for acid detection

“…Previous study shows poly(thiophene methine)s' potential usage for the acid detection because of proton trapping mechanium . To examine the selectivity of the P1 ‐sensing systems, the absorption responses of the P1 ‐acid were measured with 7 different organic and inorganic acids.…”

“…Acid Sensing Properties Previous study shows poly(thiophene methine)s' potential usage for the acid detection because of proton trapping mechanium. 70,71 To examine the selectivity of the P1-sensing systems, the absorption responses of the P1-acid were measured with 7 different organic and inorganic acids. The results show that four of BF 3 ÁOEt 2 , MeSO 3 H, HCl, and HNO 3 exhibit drastic response with the variation in absorption values of 0.03-0.07 at three typical peaks at 500, 590, and 714 nm.…”

Unravelling the detailed microstructure of a semiconducting (quasi‐metal) soluble polymer incorporating conjugated thienylene methine sequences

“…Poly(3,4‐dimethyl‐2,5‐thienylene methylene), poly(DMTM), studied here was obtained through the acid‐catalyzed polycondensation of 2‐acetoxymethyl‐3,4‐dimethylthiophene (AMDMT) carried out as described previously 17. Dichloromethane (CH 2 Cl 2 , Aldrich ≥ 99.9%) used as solvent for UV–vis analysis, methanesulfonic acid (MeSO 3 H, Aldrich ≥ 99%), trifluoroacetic acid (TFA, Fluka ≥ 98%), trifluoromethanesulfonic acid (CF 3 SO 3 H, Aldrich ≥ 99%), triphenylcarbenium hexafluorophosphate [(C 6 H 5 ) 3 CPF 6 , Aldrich], boron trifluoride ethyl etherate (BF 3 ·Et 2 O, Fluka purum), and molecular iodine (I 2 , Fluka ≥ 99.8%), used as dopants, and triethylamine (TEA, Fluka ≥ 99.5%), used for neutralization in the UV–vis analysis, were all used as received.…”

“…We recently studied the polycondensation of a series of thiophene‐methylene (ThCH 2 ) monomers bearing an acetate moiety15–17 and discovered that the ensuing macromolecules displayed two major types of sequences, namely, the expected nonconjugated repetition of 2,5‐thienylene methylene units A (Fig. 1) and conjugated counterparts alternating aromatic‐type 2,5‐thiophene and quinoid‐type exounsaturated 2,5‐thiophene moieties joined by a methine bridge B (Fig.…”

“…1). Interestingly, these polymers showed a remarkable aptitude to dissolve in common organic media and displayed a good thermal stability, even in the presence of oxygen 17…”