π‐conjugated polymers having diaza[12]annulene rings and aminopenta‐2,4‐dienylidene groups generated by the ring opening of pyridinium rings

Abstract

Reactions of N‐(2,4‐dinitrophenyl)pyridinium chloride with 2,5‐dimethyl‐1,4‐phenylenediamine in 1:2, 1:1.5, 1:1, and 2:1 molar ratios caused the ring opening of the pyridinium ring and thereby yielded polymers (P1–P4) consisting of 5‐(2,5‐dimethyl‐1,4‐phenylene)penta‐2,4‐dienylideneammonium chloride (unit A) and N‐2,5‐dimethyl‐1,4‐phenylene diaza[12]annulenium dichloride (unit B). The 1H NMR spectra suggested that the composition ratios of unit A to unit B in P1–P4 were 0.98:0.02, 0.94:0.06, 0.81:0.19, and 0.79:0.21, respectively. P1–P4 showed an absorption maximum (λmax) at a longer wavelength than the monomers because of the expansion of the π‐conjugation system. Films of P3 and P4 showed λmax at a considerably longer wavelength than those in solution, and this was attributable to the ordered structures of the polymers in the solid state. Powder X‐ray diffraction analysis supported the ordered structures of P3 and P4. Pellets molded from P3 and P4 exhibited a metallic luster, whereas those from P1 and P2 did not show such a luster. Cyclic voltammetry measurements indicated that P1–P4 were electrochemically active in films. The thermal stability of the polymers depended on the composition ratios of unit A to unit B. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1507–1514, 2007

Polymer Possessing Diaza-18-crown 6-Ether Linked by π-Conjugated Aminopenta-2,4-dienylidene Groups Generated by Ring-opening of Pyridinium Ring

“…7 The polymers were consisted of 5-(2,5-dimethyl-1,4-phenylene)penta-2,4-dienylideneammonium chloride unit and N-2,5-dimethyl-1,4-phenylene diaza [12]annulenium dichloride unit that were generated by ring-opening of the pyridinium ring of 1.…”

1,7‐Diaza[12]annulene Derivatives? 100‐Year‐Old Pyridinium Salts!

“…They conceded the similarity of their data with those of pyridinium salts and referred to a correction that they had submitted, but insisted in one case on “conclusive” evidence against a pyridinium salt based on conductivity measurements. Polymers containing moieties of the alleged 1 had also been described by YGS in an additional paper 8. On my second objection (17 October 2007), YGS replied that they had sent an e‐mail to the editor of Organic Letters for retraction of their work 2…”