• Title/Summary/Keyword: Pyrrole

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First Hyperpolarizabilities of Heteroaromatic Stilbene Derivatives

  • Cho, Bong-Rae;Lee, Sang-Hae;Yosep Min;Kang, Tae-Im;Jeon, Seung-Joon
    • Journal of Photoscience
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    • v.8 no.2
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    • pp.79-82
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    • 2001
  • 2-(p-Diethylaminostyryl)pyrrole (I) and 2-[5-diethylaminothienyl]vinyl]pyrrole (II) derivatives with systematic variation of the acceptors have been synthesized and their first hyperpolarizabilities were measured. The $\beta$ values increased systematically as the aromatic resonance energy decreased. Moreover, the value of $\beta$ for the former increased gradually as the acceptor strength increased. The opposite trend observed in the latter series of compounds has been attributed to the distorted structure caused by the steric hindrance between the N-methyl group and the acceptor moiety.

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Study on the Chemical Polymerization of Pyrrole in the Presence of Cyclic Poly(oxyethylene)s (환형 폴리옥시에틸렌 존재하의 피롤의 화학적 중합에 관한 연구)

  • 차국찬;김진환;배진영
    • Polymer(Korea)
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    • v.26 no.5
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    • pp.568-574
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    • 2002
  • Inclusion compounds using cyclic poly(oxyethylene)s as host molecules have been used to polymerize pyrrole chemically in aqueous medium. This general synthetic strategy makes it possible to grow rigid aromatic polymers in aqueous medium by chemical oxidation method. It is an easy method to obtain rigid polymers in a very mild manner. Some threaded and water-soluble polypyrroles are obtained, and their characterization is performed by NMR, IR, UV, and MALDI-TOF MS measurements.

Electrochemical Polymerization of Pyrrole from Aqueous Solutions : 2. Growth Kinetics of Polypyrrole p-toluenesulfonate Film

  • Eui Hwan Song;Woon-Kie Paik;Jung-Kyoon Chon
    • Bulletin of the Korean Chemical Society
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    • v.11 no.1
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    • pp.41-44
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    • 1990
  • The rates of electropolymerization of pyrrole from aqueous solutions containing p-toluenesulfonic acid were studied as functions of the concentration of the surfactant anions and of temperature for the polymerization on the electrode surface immersed in the solution and also for the polymerization along the solution surface. In the case of the solution-surface polymerization, the polymerization rate showed maximum as the concentration of the p-toluenesulfonic acid changed at a fixed temsperature or as the temperature was varied at a fixed concentration. The decrease of the polymerization rate with increasing concentration or with rising temperature beyond the values at the maxima is interpreted as resulting from micelle formation.

Facile Syntheses of Modified Tripyrranes and Their Application to the Syntheses fo Regioisomerically Pure Porphyrin Derivatives

  • 허필연;이창희
    • Bulletin of the Korean Chemical Society
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    • v.17 no.6
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    • pp.515-520
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    • 1996
  • Simple conditions were discovered to afford tripyrranes by reaction of 2,5-bis(α-hydroxymethyl)furan or 2,5-bis(α-hydroxy-α-phenylmethyl)thiophene with excess pyrrole in the presence of acid catalyst. Stepwise synthesis of porphyrins with core-ligand modification and synthesis of meso-tetraarylporphyrins bearing two different substituents in cis orientation have developed as building blocks for the various porphyrin-based model systems. Consequently, 21-thia-23-oxa-10,15-diphenylporphyrin (28), 21-oxa-10,15-diphenylporphyrin (29) and 21-oxa-23-carba-12-aza-10,15-diphenylporphyrin (30) were synthesized by acid-catalyzed [3+1] condensation between tripyrranes and 2,5-bis(α-hydroxymethyl)pyrrole or 2,5-bis(α-hydroxy-α-phenylmethyl)thiophene. The synthetic pathway described here gave regioisomerically pure porphyrins and thus overcame the synthetic problems associated with separation and purification of regioisomeric mixture.

Intramolecualr cyclization of a dipyrromethane by an electrophilic aromatic substitution reaction producing a new chiral compound

  • Kim, Seung Hyun;Kim, Sung Kuk
    • Journal of the Korean Magnetic Resonance Society
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    • v.22 no.4
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    • pp.115-118
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    • 2018
  • Dipyrromethane 2 functionalized with 3-chloropropyl group on the meso carbon undergoes an unusual intramolecular electrophilic aromatic substitution reaction in the presence of $NaN_3$ instead of a simple nucleophilic substitution reaction. As a result, a new chiral dipyrromethane 1 was synthesized. In this reaction, the ${\beta}$-carbon of the pyrrole ring functions as a nucleophile while the carbon next to the chlorine atom acts as an electrophile. Interestingly, this reaction progresses even in the absence of an acid catalyst. Compound 1 was fully characterized by $^1H-^1H$ and $^1H-^{13}C$ COSY NMR spectroscopic analyses and the high resolution EI mass spectrometry.