• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.102-110
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• 1983

The effect of pressure and temperature on the stabilities of the benzene-iodine charge transfer complex have been investigated through ultraviolet spectrophotometric measurements in n-hexane. The stabilities of the complexes were measured at temperatures of 25, 40 and $60^{\circ}C$ up to 1600 bars. The equilibrium constant of the complex formation 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 at 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.

• Journal of the Korean Chemical Society
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• v.22 no.4
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• pp.245-253
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• 1978

The effect of pressures and temperatures on the stabilities of the p-xylene-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∼1,600 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.

• YAKHAK HOEJI
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• v.54 no.1
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• pp.13-21
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• 2010

The interaction of cadmium (II) ion with quercetin, qurecitrin and (+)-catechin was investigated in aqueous solution at various pH. The flavonoid/cadmium stochiometries for cadmium (II) binding to flavonoid have been determined by UV-visible spectroscopy. 1:1 Cd(II)-Flavonoid complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH, that occurs upon complexation, is due to a ligand-tometal charge transfer. The optimal concentration of Cd(II)-flavonoid complexes showed that complexation reaction could be classified in the following way: 55.27 ${\mu}M$ catechin > 54.72 ${\mu}M$ quercetin > 53.52 ${\mu}M$ quercitrin at the chelating site level. These results suggest that Cd(II)-flavonoid complex has the optimal condition of chelation in 0.2 M $NH_3$ - 0.2 M $NH_4Cl$ (pH 8.0) solution.

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1166-1172
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• 1997

[FeⅢ(BLPA)DBC]BPh4, a new functional model for the catechol dioxygenases, has been synthesized, where BLPA is bis((6-methyl-2-pyridyl)methyl)(2-pyridylmethyl)amine and DBC is 3,5-di-tert-butylcatecholate dianion. The BLPA complex has a structural feature that iron center has a six-coordinate geometry with N4O2 donor set. It exhibits EPR signals at g=5.5 and 8.0 which are typical values for the high-spin FeⅢ (S=5/2) complex with axial symmetry. The BLPA complex reacts with O2 within a few hours to afford intradiol cleavage (75%) and extradiol cleavage (15%) products which is very unique result of all [Fe(L)DBC] complexes studied. The iron-catecholate interaction of BLPA complex is significantly stronger, resulting in the enhanced covalency of the metal-catecholate bonds and low energy catecholate to FeⅢ charge transfer bands at 583 and 962 nm in CH3CN. The enhanced covalency is also reflected by the isotropic shifts exhibited by the DBC protons, which indicate increased semiquinone character. The greater semiquinone character in the BLPA complex correlates well with its high reactivity towards O2. Kinetic studies of the reaction of the BLPA complex with 1 atm O2 in CH3OH and CH2Cl2 under pseudo-first order conditions show that the BLPA complex reacts with O2 much slower than the TPA complex, where TPA is tris(2-pyridylmethyl)amine. It is presumably due to the steric effect of the methyl substituent on the pyridine ring. Nevertheless, both the high specificity and the fast kinetics can be rationalized on the basis of its low energy catecholate to FeⅢ charge transfer bands and large isotropic NMR shifts for the BLPA protons. These results provide insight into the nature of the oxygenation mechanism of the catechol dioxygenases.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3109-3112
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• 2009

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1249-1255
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• 2007

We have investigated the photophysical properties of dansyl-N-methylaminobenzoic acid (DABAH) as a ligand and its lanthanide (Ln3+)-cored complexes (Ln3+-(DABA)3(terpy)) in order to determine the main energy transfer pathway for sensitized near infrared emission of Ln3+ ions (Ln3+ = Nd3+ and Er3+) in Ln3+- (DABA)3(terpy). The fluorescence spectrum of DABAH shows a large Stokes shift with increasing solvent polarity. This large Stokes shift might be due to the formation of a twisted intramolecular charge transfer (TICT) state, as demonstrated by the large dipole moment in the excited state. It is in good agreement with the result that the phosphorescence even in the Gd3+-cored complex based on the DABAH ligand was not observed, maybe due to the highly forbidden character of the S1 → T1 transition in the DABAH ligand. A short decay component (ca. 1 ns) was observed in Er3+-(DABA)3(terpy) whereas the fluorescence lifetimes of DABAH and its Gd3+-(DABA)3(terpy) are observed about ~10 ns. The short component could be originated from the energy transfer process between the ligand and the Ln3+ ion. Based on the fluorescence of DABAH its Ln3+- (DABA)3(terpy), the sensitization of Ln3+ luminescence in the Ln3+-(DABA)3(terpy) takes place by the energy transfer via the TICT state of DABAH in the excited singlet state rather than via the excited triplet state.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.335-343
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• 1993

The maximum absorption wavelengths of charge-transfer complexes of naphthalene, ${\alpha}-and{\beta}-methyl$ naphthalene and 1,2-, 2,3-and 2,6-dimethyl naphthalene with chloranil have been measured with a UV spectrophotometer in ethylene chloride, methylene chloride, and chloroform at 10, 15, 20, and 25$^{\circ}C$. This absorption band was interpreted as the charge transfer band of a 1 : 1 molecular complex, and the maximum absorption wavelength was changed as a function of solvent and temperature. Their formation constants (K$_f$) were decreased with the polarity of solvent and the increase of temperature. Thus, the influences of solvent and temperature on the formation constant have been discussed as consideration of thermodynamic properties, and the electronic and steric effects of electron donors on formation constant have been also discussed.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.99-103
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• 2013

An emzymatic bioanode for a glucose/oxygen biofuel cell was prepared by the sequential coating of carbon nanotube (CNT), charge transfer complex (CTC) based on tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF), glucose oxidase (GOx), and polyion complex (mixture of poly-L-lysine hydrobromide and poly (sodium 4-styrenesulfonate)) on a glassy carbon electrode. A biocathode was also prepared by the sequential coating of CNT, bilirubin oxidase (BOD), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and polyion complex. The effect of CNT and CTC on the electrochemical performance was investigated. The biofuel cell exhibited a promising performance with maximum power densities of 3.6, 10.1, and $46.5{\mu}W/cm^2$ at 5, 20, and 200 mM of glucose concentration, respectively. The result indicates that the biofuel cell architecture prepared in this study can be used in the development of biofuel cells and biosensors.

• Polymer(Korea)
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• v.34 no.4
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• pp.376-380
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• 2010

Donor-$\pi$-acceptor (D-$\pi$-A) type chromophore-based polymers were newly synthesized. These polymers exhibited absorption peak due to intramolecular charge transfer (ICT) in a visible range as well as absorption peak due to carbonyl group in both solution and film state by measuring UV visible spectra. The addition of $Eu^{3+}$ ion into the polymers induced red-shift in absorption due to ICT and the color changes from yellow to red in the solution and film were observed by naked eyes. The contents of crosslinking agent influenced the features and solubility of the polymers. In addition, the contents of crosslinking agent and the $Eu^{3+}$ ion addition improved film-forming ability.

• 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.