• Journal of the Korean Chemical Society
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• v.39 no.11
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• pp.856-862
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• 1995

The tungsten oxo-nitrosyl complexes (n-Bu4N)2[W5O12(NO)2{RC(NH2)NHO}2{RC(NH)NO}2] (R=(CH3)2CH, CH3CH2CH2, CH3SCH2) have been synthesized by the reactions of polyoxotungsten complex (n-Bu4N)2[W6O19] and tungsten dinitrosyl monomeric complex [W(NO)2(acac)(CH3CN)2](BF4) with butylamidoxime derivatives. The prepared complexes have been characterized by elemental analysis, infrared, UV-visible, 1H NMR and 13C NMR spectroscopy. The pentanuclear species was formed by the interaction of the electron-withdrawing {W(NO)2}2+ unit between the two dinuclear tungsten {W2O5}2+ cores. We can estimate to exist large proton interactions viewed from the four doublet in 1H NMR spectrum of (n-Bu4N)2[W5O12(NO)2{(CH3)2CHC(NH2)NHO}2{(CH3)2CHC(NH)NO}2]. We also drew informations of the two different coordination mode and symmetry of the complexes because two ligands appear in 13C NMR spectra instead of four. The {W(NO)2}2+ unit has been cis-form and C2v symmetry in geometric structure.

• KSBB Journal
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• v.16 no.4
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• pp.409-414
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• 2001

Biosynthesis of curdlan( ${\beta}$-1,3 glucan) was shown by fluorscence on cellufluor medium. The highest production of curdlan was produced when glucose was used as a carbon source and ($NH_4$)$_2$$SO_4$ was used as a nitrogen source. ${\beta}$ -form of curdlan was detected in the fingerprint region (890 $cm^{-1}$) by FT-IR spectrum and shown homogeneous ${\beta}$ -1,3 glucan by $^{13}C$ NMR spectrum ($C_1$-103 ppm, $C_2$-73.2 ppm, $C_3$-86.4 ppm, $C_4$-68.7 ppm, $C^{5}$-76.63 ppm, $C_{6}$-61.2 ppm). Transition of structure from triple helix coil form to random coil form was appeared at 0.1 ∼0.25 M NaOH concentration. It was shown that natural curdlan is a triple helix form in neutral but becomes weak in alkaline condition.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.679-684
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• 1992

New Pd(IV) complexes have been prepared through the reactions of $trans-[Pd(en)_2Cl_2](ClO_4)_2 $(en = ethylenediamine) with Guanine, Adenine, or Uracil anion as purine and pyrimidine base. We identified the ratio of central metal versus ligands by $C{\cdot}H{\cdot}N$ elemental analysis and proposed the coordinating site of the base by infrared spectrum, $^1H-NMR,\; and\; ^{13}C$-NMR spectrum. Guanine or Adenine ligand coordinated at N7 site and an en ligand exchanged for $ClO_4^-$ counter ions of the starting material . As these results, the complexes showed the formula $[Pd(en)L_2(ClO_4)_2](ClO_4)_2{\cdot}(en)$, (L = Guanine, Adenine). But in the Uracil complex no exchange of the en ligand and $ClO_4^-$ occured and Uracil anion preferred the N1 to N3 as coordinating site, the complex $[Pd(en)_2(Urac)_2](ClO_4)_2(Urac = Uracil anion).$

• Polymer(Korea)
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• v.35 no.4
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• pp.308-313
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• 2011

The ring-opening isomerization polymerization behavior of 2,5,6,7-tetrahydro-3H-imidazo[2,1-b] [1,3] oxazine(TII) has been studied under various conditions. The present study aimed at improving the low polymerizability of the above monomer (six-membered ring) up to a level comparable to that of 2,5,6-tetrahydroimidazo[2,1-b] [l,3] oxazole(TIO) (five-membered ring). The optimum result could be observed when methyl trifluoromethanesulfonate(MeOTf) and nitrobenzene were used as an initiator and a solvent in the polymerization at $60^{\circ}C$ for 24 h. Polymers were confirmed by$^1H$ NMR과$^{13}C$ NMR, and m measurements. The molecular weight obtained by gel permeation chromatography (GPC) corresponded to the molecular weight theoretically calculated from the feed ratio. The melting temperature ($T_m$) of TII was conspicuously different from that of TIO, because of the difference in the alkyl group.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.146.2-146.2
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• 2011

Molecular behaviors and crystal structures of the binary hydrates of $CH_4$ and ethanol were identified by means of 13C solid-state NMR and powder XRD methods at various concentrations of ethanol. In addition, NMR peak areas were used to calculate cage occupancies for both guest species. Obtained results showed that more $CH_4$ molecules are captured into hydrate phase per unit mass of ethanol molecules because $CH_4$ molecule can occupy sII large cages more, and pure $CH_4$ hydrate can form more as well at lower ethanol concentrations. Even though tuning phenomenon was already reported for some aqueous hydrate promoters such as THF, aqueous ethanol solutions are found to play the same tuning role in the binary clathrate hydrates in this study.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1386-1391
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• 1999

The methanol extract of Gardenia jasminoides Ellis showed antimicrobial activity against bacteria and yeasts. The extract was successively purified with solvent fractionation, silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, octadecylsilane column chromatography. The purified active substance was isolated by high performance liquid chromatography. The isolated compound was 3,4-dihydroxybenzoic acid which was determined by mass spectrometer, gas chromatograph-mass spectrometer, $^{1}H-nuclear$ magnetic resonance, $^{13}C-nuclear$ magnetic resonance and two-dimensional nuclear magnetic resonance. The content of 3,4-dihydroxybenzoic acid was $32.7\;{\mu}g/g$ in dried fruits of Gardenia jasminoides Ellis.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.339-345
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• 2007

Urea reacts with PtCl2, H2[PtCl6]·6H2O, H2[IrCl6] and Ni(CH3CO2)2 in aqueous solution at high temperature (60-80 °C) yielding [PtCl2(Urea)]·2H2O (1), (NH4)2[PtCl6] (2), (NH4)2[IrCl6]·H2O (3) and [Ni2(OH)2(NCO)2(H2O)2] (4) complexes, respectively. In complex 1, urea coordinates to Pt(II) as a neutral bidentate ligand via amido nitrogen atoms. In complexes 2, 3 and 4 it seems that the coordinated urea molecules decompose during the reaction at high temperature and a variety of reaction products are obtained. All complexes were isolated in moderate yields as dark green (1), yellow (2), pale brown (3) and faint green (4) precipitates, respectively. The reaction products were characterized by their microanalysis, IR, 1H and 13C NMR spectra as well as thermal analysis. General mechanisms describing the formation of these complexes were suggested.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.256-261
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• 2011

A new series of bis acetylated hybrid pyrazoles were synthesized and characterized by their melting point, elemental analysis, MS, FT-IR, one-dimensional $^1H$, and $^{13}C$ NMR spectroscopic data. All the synthesized compounds were tested for their in vitro antifungal activities against Candida sp. namely Candida albicans, Candida glabrata, Candida parapsilosis, Candida dubliniensis and Candida tropicalis. A close inspection of the in vitro anticandidal activity profile in differently electron donating ($CH_3$ and $OCH_3$) and electron withdrawing (-F, -Cl, and Br) functional group substituted phenyl rings of novel hybrid pyrazoles exerted strong anticandidal activity against all the tested Candida species.

• Polymer(Korea)
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• v.25 no.6
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• pp.759-764
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• 2001

In order to obtain PEO with reduced crystallinity, novel PEO derivatives containing carbonate linkages in the main chain have been synthesized by the reaction of various molecular weight poly (ethylene glycol)s (PEGs) with dimethyl carbonate (DMC) in the presence of $H_2SO_4$ to yield methyl carbonate terminated PEGs, followed by condensation reaction under vacuum in the presence of titanium isopropoxide (TiP) catalyst. The number average molecular weight of PEGs used was in the range of 200 and 600 g/mol. The structure and compositions of the resulting polymers were characterized by $^1$H-NMR and $^{13}C-NMR$. Their thermal behavior and molecular weight were characterized by DSC/TGA and GPC, respectively.

• Journal of Korea Foresty Energy
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• v.24 no.2
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• pp.16-23
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• 2005

The air dried of Epimedium koreanum Nakai was extracted with MeOH and its extractives were concentrated with a vacuum evaporator. The extractives were fractionated with a series of n-hexane, chloroform (${CHCl}_3$), butanol (BuOH), ethyl acetate (EtOAc) and water on a separately funnel. Each fraction was freeze dried to give some dark brown powder. The EtOAc and BuOH soluble fractions were chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-n-hexane mixture as eluents. The isolated compounds were tested with a cellulose TLC developed with TBA and 6% acetic acid and then visualized on UV lamp or sprayed with vanillin-HCl-EtOH. The purified compounds were flavonoids and their glycosides, and organic acid as follows : (+)-catechin, icariin, hyperoside, Ikarisoside A and caffeic acid. The structures of each compounds were confirmed by $^1H-NMR,\;^{13}C-NMR$ and Mass spectra. Also, executed qualitative analysis as use GC/MS(Libraries search) about ${CHCl}_3$ soluble compounds of each part.