• Macromolecular Research
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• v.10 no.5
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• pp.241-245
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• 2002

A new aromatic diamine monomer containing benzoxazole substituents was prepared by a multi-step synthesis starting from 1,4-dibromo-2,5-difluorobenzene. This bulky and disc-shaped monomer was polymerized with commercial dianhydride monomers to give several different poly(amic acid)s with their inherent viscosities in the range of 0.24-0.35 dL/g. The prepared polymers were soluble in typical polar aprotic solvents. Thermal imidization to the corresponding polyimides were investigated by using FT-IR, DSC and TGA.

• Preventive Nutrition and Food Science
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• v.6 no.2
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• pp.133-135
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• 2001

The edible part of cucurbita moschata Duch, which is commonly used as a Korean traditional medicine as well as a popular food source, was studied to isolate anti-complementary substance. Extracts of Cucurbita moschata Duch showed significant anti-complementary activities on the classical pathway of the complement system. Especially, the ripe Cucurbita moschata Duch had more activity than that of the complement system. Especially, the ripe Cucurbita moschata Duch had more activity than that of the green one in terms of the overall anti-complementary activity. Among the extracts of various organic solvents of the ripe Cucurbita moschata Duch, chloroform and ethyl-acetate extracts, which are non-polar solvent extracts, showed the strongest activities. These results suggest that the major difference in the solvent extraction for the anti-complementary substances depends on the change in the chemical composition such as the fatty acid with the degree of ripening.

• Journal of Photoscience
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• v.4 no.1
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• pp.1-5
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• 1997

A hitherto unknown diphenylbutadiene analog viz. 1-(p-N,N-dimethylaminophenyl)-4-phenyl-2-methyl-1E,3E-butadiene (10) has been prepared and its absorption, excitation, and fluorescent emission properties in different media including various organic solvents and aqueous bovine serum albumin (BSA) have been studied. For comparision, these properties have also been investigated for the parent diphenylbutadiene (2). Diene 10 exhibits solvent polarity/polarizability-sensitive fluorescence properties ($\lambda$$_{max}$, $\Phi$$_f$, $\tau$$_f$, K$_f$, f). It also binds to the hydrophobic domains of aqueous bovine serum albumin (BSA) with a binding constant of 3.89 x 10$^4$ M$^{-1}$. The relative fluorescence quantum yield of 10 increases, while, the fluorescence lifetime decreases with increasing concentration of-BSA. The results highlight the polar character of the singlet excited state of diphenylpolyenes and the utility of 10 as fluorescence probe for studying microenvironments of organized assemblies and biological supramolecular structures.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.255-265
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• 2006

The oxidation of hydrazobenzene by molecular oxygen in the polar solvent methanol is catalysed by a Schiff's base complex Co(3MeOsalen) which is a synthetic oxygen carrier. The products are trans-azobenzene and water. The rate of the reaction has been studied spectrophotometrically and the rate law established. A mechanism involving a ternary complex of catalyst, hydrazobenzene and molecular oxygen has been proposed. The kinetic studies show that a ternary complex $CoL{\cdot}H_2AB{\cdot}O_2$ is involved in the rate determining step. The reactions are summarised in a catalytic cycle. The kinetic data suggest that a ternary complex involving Co(3MeOsalen), triphenyl-phosphine and molecular oxygen is catalytically acive species but at higher triphenylphosphine concentrations the catalyst becomes inactive. The destruction of the catalytic activity could be due to the catalyst becoming coordinated with triphenyl phosphine at both z axis sites of the complex e.g. Co (3MeOsalen)$(PPh_3)_2$.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.379-382
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• 2000

Conditions of isolation for the red color pigments from the Korean Lithospermum erythrorhizon were investigated and identification of the red pigment was analysed. Non-polar solvents were more effective than water. Especially, 95% ethanol was observed as optimum solvent for the pigments extraction. About 20 minutes at 40$^{\circ}C$ with 95% ethanol was enough for the extraction of the red pigments. The major pigment was analysed as acetylshikonin by TLC, IR, NMR and GC/MS.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.1037-1040
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• 2011

The dinuclear complex 1 with cooperative hydrogen bonds can be prepared by the metal-directed reaction of Eq. (2). This work shows that the coordinated hydroxyl group trans to the secondary amino group is deprotonated more readily than that trans to the tertiary amino group and acts as the hydrogen-bond accepter. The lattice water molecules in 1 act as bridges between the two mononuclear units through hydrogen bonds. The complex is quite stable as the dimeric form even in various polar solvents. The complex exhibits a weak antiferromagnetic interaction between the metal ions in spite of relatively long Cu$\cdots$Cu distance. This strongly supports the suggestion that the antiferromagnetic behavior is closely related to the cooperative hydrogen bonds.

• YAKHAK HOEJI
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• v.25 no.4
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• pp.193-197
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• 1981

Germanium (Ge) content in Zingiberis Rhizoma was determined by flameless atomic absorption spectrometry with a graphite tube atomizer. The Ge content of the cortical layer was 65.mu.g/g, the central cylinder, $98\mu$g/g and the total, $87\mu$g/g. In the effect of the extraction of Ge by various solvents, polar solvent was more effective than the nonpolar one, Especially, water was the most effective solvent. The water extract of Zingiberis Rhizoma, separated by sephadex G-25 gel filtration, was fractionated into 2 peaks at 254nm. Both the peaks showed atomic absorptions of Ge. It may be concluded that the Ge components of Zingiberis Rbizoma exist as the form of an aqueous organic compounds or associated forms with proteins.

• Journal of Photoscience
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• v.11 no.3
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• pp.107-113
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• 2004

Synthesis, absorption and fluorescence properties of 3-methyl indole (1), N-(benzenesulfonyl)-3-(3-oxo-but-1-enyl)-indole (2) and 1H-3-(3-oxo-but-1-enyl)-indole (3) are described. Extended conjugation at C-3 of indole as in 3 causes moderate resolution of $^1L_a$ and $^1L_b$ bands. However, 2 having an electron-withdrawing group at indolic nitrogen shows only the $^1L_a$ band. While the $^1L_b$ band largely remains solvent polarity independent, the $^1L_a$ band undergoes moderate red shift in polar solvents. The fluorescence in 2 and 3 originates from the $L_b$ transition. Additionally, interaction of 2 and 3 with BSA indicates that these compounds bind to the hydrophobic site of BSA with the formation of a highly fluorescent BSA-probe complex.

• Textile Coloration and Finishing
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• v.6 no.1
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• pp.28-32
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• 1994

The synthesis and absorption spectra of squarvlium(SQ) dyes and croconium(CR) dyes were .studied. Absorption spectra of SQ dye in various solvents exhibited a negative solvatochrornism. Thus, it was suggested that the structure of SQ dye may be a highly polar structure. The λ$_{max}$ of CR dyes undergoes a bathochromic shift of about 100nm compared with the corresponding SQ dyes. This shift can be calculated by the Pariser-Parr-Pople molecular orbital method. From the PPP MO calculation results, we found that SQ dye and CR dye have a almost same Highest Occupied Molecular Orbital(HOMO) level(SQ : -8.0eV, CR : -8.09eV). On the other hand, energy levels of Lowest Unoccupied Molecular Orbital(LUMO) of SQ and CR dyes are -4.09eV and -4.13eV respectively. Thus, replacement of five membered ring by four membered ring in SQ dye causes a large bathochromic shift.t.

• Bulletin of the Korean Chemical Society
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• v.19 no.7
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• pp.738-742
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• 1998

A new polyamide was prepared from 4,4'-(hexafluoroisopropylidene)di-aniline and 4-[NN-bis(2-carboxyethyl)] amino-4'-nitrostilbene. This polymer was cast into thin films by spin coating cyclohexanone solution. After being poled, the electro-optic coefficients of electrode poled polymer films were measured by the reflection measurement technique using an incident laser beam of 1.3 Jim. The film poled at the field strength of 1.2 V/μm exhibited the electro-optic coefficient (r33) of 5.9 pm/V. The relaxation behavior of the poled polymer film was compared with other reported polymers bearing the same NLO chromophores. Due to stiff and highly polar nature of the backbone and also due to formation of interchain hydrogen bonds, this polymer reveals a slower relaxation characteristics. The polymer is amorphous and soluble in various organic solvents.