• Title/Summary/Keyword: charge transfer complex

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Electrical Bistable Characteristics of Organic Charge Transfer Complex for Memory Device Applications

  • Lee, Chang-Lyoul
    • Applied Science and Convergence Technology
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    • v.24 no.6
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    • pp.278-283
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    • 2015
  • In this work, the electrical bistability of an organic CT complex is demonstrated and the possible switching mechanism is proposed. 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and tetracyanoquinodimethane (TCNQ) are used as an organic donor and acceptor, respectively, and poly-methamethylacrylate (PMMA) is used as a polymeric matrix for spin-coating. A device with the Al/($Al_2O_3$)/PMMA:BCP:TCNQ[1:1:0.5 wt%]/Al configuration demonstrated bistable and switching characteristics similar to Ovshinsky switching with a low threshold voltage and a high ON/OFF ratio. An analysis of the current-voltage curves of the device suggested that electrical switching took place due to the charge transfer mechanism.

Study of Solvent Effects in Diels-Alder Reaction through Charge Transfer Formation by Using Semi-empirical Calculations

  • Shihab, Mehdi Salih
    • Bulletin of the Korean Chemical Society
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    • v.29 no.10
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    • pp.1898-1904
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    • 2008
  • Study of computational model of the concerted Diels-Alder reaction between 9,10-dimethyl anthracene (as donor) and tetracyanoethylene (as acceptor) in absence and in presence of aromatic solvents (benzene, mesitylene and hexamethylbenzene, as donors) using an AM1 semi-empirical method. AM1 method used to study the neutral charge transfer complex models that could be expected between donor and acceptor during the course of the concerted Diels-Alder reaction. Calculated enthalpies of reaction of the charge transfer complexes models showed physical and chemical meaning for explain the effect of aromatic solvents on the kinetic process of concerted Diels-Alder reaction that contains tetracyanoethylene.

Optical Transmittance of Polybenzoxazole Precursor (폴리벤조옥사졸 전구체의 광투과도 연구)

  • 김대겸;김종화;최길영;오재민;이무영;박동원;이광섭;진문영
    • Polymer(Korea)
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    • v.26 no.1
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    • pp.18-27
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    • 2002
  • Poly(ο-hydroxyamide)s as polybenzoxazoles precursors were synthesized by polycondensation from 2,2'-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and various bis-acids. And the polymers were modified to acid-sensitive polyamides by introducing tetrahydropyran in order to impart photosensitivity. A study of optical transmittance at 365 nm, according to the chemical structure of bis-acid, revealed that the polymer derived from 4,4'-oxydibenzoic acid showed better optical transparency than those from other bis-acids. This tendency of optical transmittance could be explained by formation of charge transfer complex. In case of the polymer derived from 4,4'-oxydibenzoic acid, the electron accepting characteristic of bis-acid is reduced by introduction of electron donating group, -O-. Thus, optical transmittance increased due to the diminished formation of intramolecular charge transfer complex. In addition, the optical transmittance increased with increasing the THP content in the polymer. This is attributed to the reduced intermolecular interaction by the loosening of the packing density of the polymer chain.

The Effects of Charge Transfer Complex on the Reaction of Aniline and Iodine (Aniline과 Iodine간의 반응에 있어서 전하이동 착물의 영향)

  • Oh-Yun Kwon;U-Hyon Paek;Eung-Ryul Kim
    • Journal of the Korean Chemical Society
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    • v.36 no.2
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    • pp.174-179
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    • 1992
  • Reaction of aniline and iodine in$CHCl_3,\;CH_2Cl_2 : CHCl_3$(1 : 1), and $CH_2Cl_2$ has been studied kinetically by using conductivity method, Pseudo first-order rate constants ($k_{obs}$) and second-order rate constants ($k_{obs}$/[aniline]) are dependent on the aniline concentration. Second-order rate constants obtained were increased with increasing aniline concentration. We analysed these results on the basis of formation of charge transfer complex as reaction intermediate. From the construction of react ion scheme and derivation of rate equation, we calculated equilibrium constants and activation parameters for the formation and transformation of charge transfer complex. The equilibrium constants were decreased by an increase in the dielectric constant of the solvent and the value is 1.7-3.7$M^{-1}$. The rate of transformation are markedly affected by the solvent polarity. ${\Delta}H^{\neq}$ is about 14.2kJ/mol, and ${\Delta}S^{\neq}$ is large negative value of -243J/mol K.

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The Effects of Charge Transfer Complex on the Reaction of N,N-dimethylaniline and Iodine (N,N-Dimethylaniline과 Iodine간의 반응에 있어서 Charge Transfer Complex의 영향)

  • Oh-Yun Kwon;U-Hyon Paek;Eung-Ryul Kim
    • Journal of the Korean Chemical Society
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    • v.36 no.2
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    • pp.191-196
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    • 1992
  • Reaction of N,N-dimethylaniline(N,N-DMA) and iodine in $CHCl_3,\;CH_2Cl_2 : CHCl_3$(1:1), $CH_2Cl_2$(1:1), and CH2Cl2 has been studied kinetically by using conductivity method. Pseudo first-order rate constants ($k_{obs}$) and second-order rate constants ($k_{obs}$/[N,N-DMA]) are dependent on the N,N-DMA concentration. Second-order rate constants obtained were decreased with increasing N,N-DMA concentration. We analysed these results on the basis of formation of charge transfer complex as a reaction intermediate. From the construction of reaction scheme and activation parameters for the formation and transformation of charge transfer complex. The equilibrium constants decreased when the dielectric constant of solvent was increased, and the value is 1.9${\sim}$4.2$M^{-1}$. The rate of transformation are markedly affected by the solvent polarity.${\Delta}H^{\neq}$ is 6.3-12.6kJ/mol, and ${\Delta}S^{\neq}$ is large negative value of -234J/mol K.

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Novel Triiodide PVC-Based Membrane Sensor Based on a Charge Transfer Complex of Iodine and Bis(2-hydroxyacetophenone)butane-2,3-dihydrazone

  • Ganjali, Mohammad Reza;Norouzi, Parviz;Shirvani Arani, Simindokht;Salavati Niasari, Masoud
    • Bulletin of the Korean Chemical Society
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    • v.26 no.11
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    • pp.1738-1742
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    • 2005
  • In this study a novel triiodide ion-selective electrode based on a charge transfer complex of iodine and Bis(2-hydroxyacetophenone)butane-2,3-dihydrazone (ICT), as a membrane carrier was prepared. The electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-2}$ and 5.0 ${\times}$ $10^{-7}$ M, with a Nernstian slope of 58. 99 ${\pm}$ 0.3 mV $decade^{-1}$ and detection limit of 3.0 ${\times}$ $10 ^{-7}$ M. The potentiometric response of the proposed sensor is independent of the pH of the solution in the pH range of 3.0-10.0. The electrode possesses the advantages of short conditioning time, fast response time, and especially, very good selectivity over a large number of common organic and inorganic anions. The electrode can be used for at least 6 months without any considerable divergences in the potentials. It was used as an indicator electrode in potentiometric titration of triiodide ion with thiosulfate.

The Effect of Pressure and Temperature on the Mesitylene-Iodine Charge Transfer Complex in n-Hexane (고압, 고온 유체의 물성연구. 메시틸렌과 요오드 사이의 전하이동착물에 대한 압력과 온도의 영향)

  • Oh Cheun Kwun;Jong Gi Jee;Jeong Rim Kim
    • Journal of the Korean Chemical Society
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    • v.24 no.6
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    • pp.405-412
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    • 1980
  • The effect of pressures and temperatures on the stabilities of the mesitylene-iodine charge transfer complex have been investigated through ultraviolet spectrophotometric measurements in n-hexane. The stabilities of complexes were measured at 25, 40 and $60^{\circ}C$ under 1∼1600 bars. The equilibrium constant of the complex was increased with pressure and decreased with temperature raising. The absorption coefficient was increased with both pressure and temperature. Changes of volume, enthalpy, free energy and entropy for the formation of complexes were obtained from the equilibrium constants. The red-shift observed a higher pressure, the blue-shift at a higher temperature and the relation between pressure and oscillator strength were discussed by means of thermodynamic functions.

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