• Title/Summary/Keyword: azomethine

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Rates and Mechanism of Fading Reaction of Magenta Azomethine Dye in Basic Solution (염기성 용액에서 마젠타 아조메틴 색소의 퇴색 반응속도와 메커니즘)

  • Lee Joong-Ho;Kim Jung-Sung;Kim Chang-Su
    • Journal of Environmental Science International
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    • v.14 no.7
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    • pp.711-717
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    • 2005
  • A magenta azomethine dye(D) was synthesized from the reaction of 3-methyl-1-phenyl-2-pyrazoline-5-one with N,N-diethyl-1,4-phenylenediamine. The magenta azomethine dye was identified on the basis of elemental analysis, $^{13}C-NMR$, infrared, and GC/MS studies. The magenta azomethine dye was decomposed in a basic solution. Rate constants of the fading reaction of magenta azomethine dye in ethanol-water solvent were measured spectrophoto­metrically at 540 nm. Reaction rate was increased with the increase of $[OH\^{-}]\;and\;[H\_{2}O]$ in the region of $[H_{2}O]=11\~40\;M$. The reaction was governed by the following rate law. -d[D]/dt = $\{k_o\;+\;k_{OH}[OH^-][H_{2O}]\}[D]$ A possible mechanism consistent with the empirical rate law has been proposed.

Silyl-Tranfer Photoreactions of Trimethylsilylmethyl Substituted Acyclic N-Sulfonylbenzamides

  • Oh, Sun-Wha
    • Journal of Photoscience
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    • v.12 no.2
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    • pp.63-66
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    • 2005
  • The azomethine ylide forming photoreaction has been explored by probing the excited state chemistry of several N-trimethylsilylmethyl substituted cyclic and acyclic imides and amide analogs. N-[(Trimethylsilyl)methyl]-N-mesylbenzamide (5) undergoes the excited state C to O silyl migration reaction to produce azomethine ylide intermediate 13. This ylide undergoes electrocyclization to form transient aziridine intermediate 14 which react further by ring opening to generate N-phenacylamine product 10. On the other hand, photolysis of N-[N-mesyl-N-(trimethylsilyl)methyl]aminoethyl-N-mesylbenzamide (8) brings about desilylation resulting in the production of dimer 17.

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Electrochemical Behavior and Differential Pulse Polarographic Determination of Rifampicin in the Pharmaceutical Preparations

  • Hahn, Young-Hee;Shin, Sun-Mi
    • Archives of Pharmacal Research
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    • v.24 no.2
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    • pp.100-104
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    • 2001
  • Differential pulse polarographic(DPP) analytical procedure for the rifampicin antibiotic, which can be applied to monitor its synthetic process from the starting antibiotic of rifamycin B or rifamycin SV has been developed based on the electrochemical reduction of an azomethine group. Rifampicin exhibited a cathodic peak due to the azomethine group in the side chain of 3-[(4-methyl-1-piperazinyl)imino]methyl moiety and another cathodic peak due to the carbonyl group in rifamycin SV by DPP. The experimental peak potential shift of an azomethine reduction was -73 mV/pH in the pH range between 3.0 and 7.5, agreeing with involvement of 4 e-and 5 $H^5$ in its reduction. By the cyclic voltammetric(CV) studies, the azomethine and the carbonyl reductions in rifampicin were processed irreversibly on the mercury electrode. The plot of peak currents vs. concentrations of rifampicin ranging $1.0{\times}10^{-7} M~$1.0{\times}10^{-5} M yielded a straight line with a correlation coefficient of 0.9996. The detection limit was $1.0{\times}10^{-8} M with a modulation amplitude of 50 mV DPP has been successfully applied for the determination of rifampicin in the pharmaceutical preparations.

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Synthesis and Characterization of New Azomethine Polymers Containing Bent-Core Mesogen with Sharp Bend Angle

  • Kim, Eun-Chol;Choi, E-Joon;Ok, Chang-Woo;Zin, Wang-Choel
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.553-555
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    • 2007
  • Six azomethine polymers containing bent-core mesogen were synthesized with variation of a bent structure of central core (1,2-dioxyphenylene or 2,3-dioxynaphthylene), and a lateral halogen substituent (X = H, F or Cl ). The properties of the polymers were characterized by FT-IR, NMR spectroscopy, DSC, polarizing optical microscopy, and X-ray diffractometry.

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Synthesis of Conjugated Copolymers with phenothiazine and Azomethine Units and their Electro-Optic Properties

  • Seo, Hyeon-Jin;Jang, Byeung-Jo;Chang, Jin-Gyu;Park, Lee-Soon
    • Journal of Information Display
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    • v.2 no.4
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    • pp.8-14
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    • 2001
  • Three types of conjugated polymers, poly(PZ-Pi), poly(PZ-BPI) and poly(PZ-NPI) were synthesized by Schiff-base reaction. These new conjugated polymers exhibited improved solubility in common organic solvents due to the presence of alkyl side chains as well as azomethine groups, Double layer LEDs made with the synthesized polymers as emitting layer and $Alq_3$, as electron transporting layer exhibited enhanced EL emission and efficiency compared to those of single layer LEDs. Double layer LEDs exhibited gradual shift in the emission peak th the single layer LED, made of only $Alq_3$ as the emitting layer as the thickness of $Alq_3$ layer increased.

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Dipole-Forming Photochemical Group Transfer Reactions of Phthalimides and ${\alpha}-Ketoamides$

  • Yoon, Ung-Chan;Mariano Patrick S.
    • Journal of Photoscience
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    • v.12 no.3
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    • pp.155-162
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    • 2005
  • Results of studies of SET-promoted dipole-forming photochemical group transfer reactions of phthalimide and ${\alpha}-ketoamide$ derivatives are discussed. Azomethine ylide forming photochemical reactions, which are initiated by intramolecular SET from tethered silylmethyl-, carboxymethyl-, and ${\beta}-hydroxyethyl$ containing electron donors to excited states of phthalimides, related maleimides, and conjugated imides, are presented first. Following this, investigations of regioselective 1,4-dipole forming photochemical reactions of N-trialkylsilylmethyl- and N-trialkylstannyl-${\alpha}$-ketoamides are described.

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Curing Reaction of Noble Liquid Crystalline Epoxy (LCE) with Azomethine/Aliphatic Amine (Azomethine 기를 가지는 신소재 액정 에폭시 (LCE)와 지방족 아민의 경화반응)

  • Kim, Sang-Uk
    • Korean Journal of Materials Research
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    • v.11 no.9
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    • pp.786-791
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    • 2001
  • $\alpha$,$\omega$-Bis(4-glycidyloxybenzylidene-4-aminophenyl)methane (BGBAM) was synthesized from the initial materials, 4-hydroxylbenzaldehyde (HBA), 4,4'-methylenedianiline (MDA) and epichlorohydrin. The DSC trace for BGBAM shows two endotherms associated with the liquid crystalline phase transition around $104.2^{\circ}C$ and the isotropic transition around $171.2^{\circ}C$, and it also has a broad exotherm in the range of $178~300^{\circ}C$ due to the anionic homopolymerization of BGBAM. DSC curve for the curing of BGBAM with hexamethylene diamine (HMD) shows an endothermic peak around $93^{\circ}C$ attributed to the melting of BGBAM. It also has three exothermic peaks around $128.4^{\circ}C$ and $180.2^{\circ}C$ associated with the epoxide-amine reaction and weak peak in the range of $200~263^{\circ}C$ related to the anionic homopolymerization between the unreacted epoxide groups. The activation energy values of cure reaction by Kissinger method are 66.5, 67.3 and 90.6 kJ/mol for $T_{pl},\; T_{p2}\; and \;T_{p3},\; respectively$. The kinetic parameters by isoconverional method are similar value to those from Kissinger method.

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Synthesis and Application of the Novel Azomethine Metal Complexes for the Organic Electroluminescent Devices

  • Kim, Seong Min;Kim, Jin Sun;Sin, Dong Myeong;Kim, Yeong Gwan;Ha, Yun Gyeong
    • Bulletin of the Korean Chemical Society
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    • v.22 no.7
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    • pp.743-747
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    • 2001
  • New azomethine metal complexes were synthesized systematically and characterized. Beryllium, magnesium, or zinc ions were used as a central metal cation and aromatic azomethines (L1-L4) were employed as a chelating anionic ligand. Emission peaks o f the complexes in both solution and solid states were observed mostly at the region of 400-500 nm in the luminescence spectra, where blue light was emitted. Three of them (BeL1 (Ⅰ), ZnL2 (Ⅱ), and ZnL3 (Ⅲ)) were sublimable and thus were applied to the organic light-emitting devices (OLED) as an emitting layer, respectively. The device including the emitting layer of Ⅰ exhibited white emission with the broad luminescence spectral range. The device with the emitting layer of Ⅱ showed blue luminescence with the maximum emission peak at 460 nm. Their ionization potentials, electron affinities, and electrochemical band gaps were investigated with cyclic voltammetry. The electrochemical gaps of 2.98 for I, 2.70 for Ⅱ, and 2.63 eV for Ⅲ were found to be consistent with their respective optical band gaps of 3.01, 2.95 and 2.61 eV within an experimental error. The structure of OLED manufactured in this study reveals that these complexes can work as electron transporting materials as well.