Polymerization of aromatic nuclei. XIX. Polymerization of thiophene by aluminum chloride

Abstract

Thiophene was polymerized in high yield on exposure to aluminum chloride in solvent under mild conditions. Experimental evidence [IR, NMR, UV, and mass spectra, elemental analyses, reductive desulfurization, and comparison with the literature trimer of thiophene (prepared with phosphoric acid)] suggests the following structure: From gel permeation chromatography an average weight of 1290 was obtained, which corresponded to the presence of 15 rings; the highest‐molecular‐weight chains contained about 192 rings. Mechanistically, participation of cationic intermediates is proposed. Apparently chain extension can occur by various routes, including participation of neutral oligomer molecules.

Oxidative Bond Formation in Dithienyl Polyphenylenes: Optical and Electrochemical Consequences

“…The latter are known to undergo Lewis acid catalyzed oxidation to give heterosuperbenzene systems [N-HSB]. [11] The prevalence of intermolecular dehydrogenations in thienyl oxidation [14,15] and the consequent problem of multiple isomeric products initially led us to sterically block the site for intermolecular dehydrogenation. To this end, a bisthienylacetylene with methyl substituents MeS 2 CCS 2Ј Me was synthesized and subsequently reacted with tert-butylsubstituted tetraphenylcyclopentadienone to give 1 (Scheme 1).…”

“…It corresponds to the increased conjugation arising from the two fused thienyl units in the dimer when they are coplanar (Scheme 3B). [14] The absorptivity of the tail is greatest for 7 in solution, indicating that the planar conformation (Scheme 3B) is more easily attained in this case. The sharp-structured absorption bands (around λ = 350-450 nm) observed for all three dimers support the idea of a high-energy barrier for the rotation of monomeric subunits through the newly formed bond.…”

Conductive polyaniline–polythiophene/poly(ethylene terephthalate) composite fiber: Effects of pH and washing processes on surface resistivity

“…It is known that thiophene is unstable and gives a non‐conjugated polymer structure in aqueous acidic medium which is favorable for the polymerization of aniline . The yield and conductivity of PTh also change according to the polarity of solvent types and solvent mixtures used as polymerization media .…”

Polymerization of aromatic nuclei. XXII. Structure of the oligomer product from thiophene and trifluoroacetic acid: A reinvestigation

“…We have repeated the work of Wassermann et a1.6 with the aim of making a detailed comparison'of data for our solid product (V), the corresponding literature material (VI), the polymer (111) from thiophene-aluminum chloride, our liquid product (VII), trimer (I), and "tetramer" (11). From the following discussion, the conclusion is drawn that the thiophene-trifluoroacetic acid oligomer is also most accurately described by structure 111.…”