• 한국자기공명학회논문지
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• 제20권1호
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• pp.1-6
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• 2016

The proton NMR line widths and spin-lattice relaxation rates, $T_1^{-1}$, of ferroelectric $LiH_3(SeO_3)_2$, $Li_2SO_4{\cdot}H_2O$, and $LiN_2H_5SO_4$ single crystals were measured as a function of temperature. The line width measurements reveal rigid lattice behavior of all the crystals at low temperatures and line narrowing due to molecular motion at higher temperatures. The temperature dependences of the proton $T_1^{-1}$ for these crystals exhibit maxima, which are attributed to the effects of molecular motion by the Bloembergen - Purcell - Pound theory. The activation energies for the molecular motions of $^1H$ in these crystals were obtained. From these analysis, $^1H$ in $LiH_3(SeO_3)_2$ undergoes molecular motion more easily than $^1H$ in $LiN_2H_5SO_4$ and $Li_2SO_4{\cdot}H_2O$ crystals.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.645-656
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• 2008

Purpose: To evaulate the effects of chlorhexidine and $H_2O_2$ on matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase(TIMP-1, TIMP-2), Type 1 collagen, fibronectin and UNCL expressions in human periodontal ligament fibroblasts (hPDLF). Materials and Methods: $1.2{\times}10^{-1}%$, $1.2{\times}10^{-2}%$ and $1.2{\times}10^{-3}%$ CHX and $3{\times}10^{-3}%$, $3{\times}10^{-4}%$ and $3{\times}10^{-5}%$ $H_2O_2$ and mixture of CHX and $H_2O_2$ were applied to hPDLF for 1 min and 30 min. The mRNA expressions of MMP-1, TIMP-1 and 2, Type 1 collagen, fibronectin and UNCL in hPDLF were analysed by RT-PCR. Results: The result were as follows: 1. The expression of UNCL mRNA was higher than that of other mRNAs. 2. $1.2{\times}10^{-3}%$ CHX increased mRNA expressions of hPDLF as application time increased. 3. $H_2O_2$ lower than $3{\times}10^{-3}%$ increased expression of UNCL mRNA, and did not decrease mRNA expression of hPDLF. 4. hPDLF treatment with $1.2{\times}10^{-1}%$ CHX (with or without $H_2O_2$) resulted in no gene expression. 5. hPDLF treatment with $1.2{\times}10^{-2}%$ CHX (with or without $H_2O_2$) for 30 minutes resulted in no gene expression. Conclusion: Because low concentration of CHX and $H_2O_2$ increased UNCL mRNA expression of hPDLF, low concentraction of CHX and $H_2O_2$ may have an antioxidative effect.

• 한국결정학회지
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• 제11권1호
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• pp.10-15
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• 2000

Compound trans-[FeH(NCS(i-Pr)-S)(dppe)₂](1) reacted with isopropyl iodide (i-PrI) to give an Fe(II)-organic isothiocyanide complex, trans-[FeH(NCS(i-Pr)-S)(dppe)₂]I (2). Compound 2 was structurally characterized, in which the hydride ligand appears to be involved in the "dihydrogen" bonding, M-H…H-C. Crystallographic data for 2: monoclinic space group P2₁/n, a=13.490(2)Å, b=17.269(3)Å, c=21.384(3)Å, β=90.682(7)°, Z=4, R(wR₂)=0.0348(0.0894).

• 약학회지
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• 제31권1호
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• pp.14-18
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• 1987

2-Substituted-3, 4-dihydro-2H-1, 2-benzothiazin-4-one 1, 1-dioxide 6 was reatced with magnesium methyl carbonate to form magnesium chelate 7, which could be hydrolized in cold hydrochloric acid solution to give 2-substituted-4-hydroxy-2H, 1, 2-benzothiazine-3-Carboxylic acid 1, 1-dioxide 2 in good yield.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1210-1215
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• 2006

The properties related to the temperature and oxygen stability of the cytoplasmic hydrogenases from the fermentative strict anaerobic bacterium, Clostridium butyricum NCIB 9576 (Cl. butyricum), and purple sulfur phototrophic bacterium, Thiocapsa roseopersicina NCIB 8347 (T. roseopersicina), were compared. The optimum temperatures for the growth of Cl. butyricum and T. roseopersicina were 37$^{\circ}C$ and 25$^{\circ}C$, respectively, whereas those for the H$_2$ evolution of the cytoplasmic hydrogenases prepared from Cl. butyricum (C-H$_2$ase) and T. roseopersicina (T-H$_2$ase) were 45$^{\circ}C$ and 65$^{\circ}C$, respectively. The T-H$_2$ase was more thermostable than the C-H$_2$ase and retained its full activity for 5 h at 50$^{\circ}C$ under anaerobic conditions and 90% of its activity at 60$^{\circ}C$, whereas the C-H$_2$ase lost its activity drastically at 50$^{\circ}C$. The optimum pHs for H$_2$ oxidation of the C-H$_2$ase and T-H$_2$ase were 9.0 and 7.5, respectively. Both enzymes showed a maximum H$_2$ evolution activity at pH 7.0. Under aerobic conditions, 80% of the T-H$_2$ase activity was retained for 10 h at 30$^{\circ}C$, and 50% of the activity remained after 6 days under the same experimental conditions. However, the C-H$_2$ase was labile to oxygen and lost its activity immediately on exposure to air. Therefore, these properties of the T-H$_2$ase are expected to be advantageous for application in in vitro biological H$_2$ production systems.

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.129-136
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• 1986

The dipole moments for some coordination compounds with organic ligands have been calculated adopting the molecuar orbitals obtained from EHT calculation with modified technique. Adopting the molecular orbitals with the modified technique, the calculated dipole moments for all the coordination compounds with organic ligands give closer agreements with experimental values than those using the molecular orbitals obtained from EHT calculation. The calculated dipole moments suggest that $(C_2H_5)_2SO,\;(C_6H_5)_2SO,\;and\;(C_6H_5)_2SeO$ may have a trigonal planar structure and $(C_6H_5)_3AsO,\;and\;(C_6H_5)_3PBCl_3$ a square planar structure and $(C_2H_5)_2OZrCl_4$ may be distorted markedly. This work may also indicate that the modified technique is superior to the EHT calculation as far as the dipole moment calculation is concerned.

• 공업화학
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• 제28권5호
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• pp.597-600
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• 2017

4,4'-비피리딘과 크롬(VI) 산화물을 반응시켜 $(C_{10}H_8N_2H)_2Cr_2O_7$을 합성하였다. 적외선분광광도법(FT-IR)과 원소분석으로 구조를 확인하였다. 여러 가지 용매 하에서 $(C_{10}H_8N_2H)_2Cr_2O_7$을 이용하여 벤질알코올의 산화반응을 측정한 결과, 용매의 유전상수 값이 증가함에 따라 반응수율이 증가했다. 그 순서는 DMF (N,N'-디메틸포름아미드) > 아세톤 > 클로로포름 > 시클로헥센이었다. $H_2SO_4$ 촉매를 이용한 DMF 용매 하에서, $(C_{10}-H_8N_2H)_2Cr_2O_7$은 벤질알코올(H)과 그의 유도체들($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, $m-NO_2$)을 효과적으로 산화시켰다. 전자받개 그룹들은 반응속도가 감소한 반면에 전자주개 치환체들은 반응속도를 증가시켰고, Hammett 반응상수(${\rho}$) 값은 -0.70 (308 K)이었다. 본 실험에서 알코올의 산화반응 과정은 속도결정단계에서 수소화 전이가 일어났다.

• 대한화학회지
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• 제43권6호
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• pp.628-635
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• 1999

활성화된 $Mn(IV)O_2$를 이용하여 2,6-bis(hydroxymethyl)-4-methylphenol로부터 2,6-diformyl-p-cresol과 2-hydroxy-3-hydroxymethyl-5-methylbenzaldehyde를 제조하였다. 2-hydroxy-3-hydroxymethyl-5-methylbenzaldehyde와 ethylenediamine 및 1,3-diaminopropane의 축합반응에 의해 6-배위 칸막이 리간드, $H_4L[A]와\; H_4L[B]$를 각각 얻었다. methanol에서 2,6-diformyl-p-cresol과 1,2-diaminobenzene으로부터 부분적으로 환원된 거대고리, $H_4[20]DOTA$를 얻을 수 있었다. 이 $H_4[20]DOTA$와 lanthanide(IlI) nitrate 간의 반응 또는 methanol에서 주형과정(template procedure)에 의해 일핵 착물, $[Ln(IIl)(H_2[20]DOTA)(ClO_4)(H_2O)]\;{\cdot}\;3H_2O과\; [Ln([20]DOTA)(NO_3)(H_2O)](NO_3)_2\;{\cdot}\;xH_2O$를 각각 합성하였다. $[Ln([20]DOTA)(NO_3)(H_2O)](NO_3)_2\;{\cdot}\;xH_2O$를 2일 정도 methanol에 정치함으로써 얻은 $[Ln([20]DOTA)(NO_3)(CH_3OH)]^{2+}$에서 배위된 $CH_3OH$이 주게원자가 O인 보조리간드, $L_a$(=salicylic acid, p-chlorobenzoic acid, benzoic acid, acetic acid, 4-bromophenol)에 의해 치환될 때 평형상수 (K)를 25$^{\circ}C$, ${\mu}$=0.1M $NaClO_4$에서 분광학적 방법으로 결정하였다. 이 때 평형상수(K) 값들은 보조리간드 pKa 크기의 반대 경향인 salicylic acid>p-chlorobenzoic acid>benzoic acid>acetic acid>4-bromophenol 순서로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.892-898
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• 2005

A long, bis(monodentate), linking Schiff-base ligand L (py-CH=N-$C_6H_4$-N=CH-py) was prepared from 1,4-phenylenediamine and 3-pyridinecarboxaldehyde by the Schiff-base condensation. Ligand L has two terminal pyridyl groups capable of coordinating to metals through their nitrogen atoms. In contrast, the same reaction between 1,2-phenylenediamine and 3-pyridinecarboxaldehyde produced a mixture of imidazol isomers (2-pyridin-3-yl-1H-benzoimidazole), which are connected to one another by the N-H…N hydrogen bonding to form a tetramer. From Zn($NO_3)_2{\cdot}6H_2O$ and ligand L under various conditions, one discrete molecule, trans- [Zn($H_2O)_4L_2]{\cdot}(NO_3)_2{\cdot}(MeOH)_2$, and two 1-D zinc polymers, [Zn$(NO_3)(H_2O)_2(L)]{\cdot}(NO_3){\cdot}(H_2O)_2$ and [Zn(L) (OBC)($H_2O$)], were prepared. In ligand L, the N$\ldots$N separation between the terminal pyridyl groups is 13.994 $\AA$, with their nitrogen atoms at the meta positions (3,3’) in a trans manner. The corresponding N$\ldots$N separations in its compounds range from 13.853 to 14.754 $\AA$.

• 대한화학회지
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• 제11권3호
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• pp.94-99
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• 1967

요오도벤젠과 요오드, 일브롬화요오드, 일염화요오드 또는 염소와의 각 系를 사염화탄소 용액에서 分光光度法에 의하여 연구한 결과 $C_6H_5I{\cdot}I_2$, $C_6H_5I{\cdot}IBr$, $C_6H_5I{\cdot}ICl$, 또는 $C_6H_5I{\cdot}Cl_2$, 의 錯物이 형성됨을 알았다. 이들 錯物형성에 대한 실온(약 $21^{\circ}C$)에서의 평형상수는 각각 0.23, 0.73, 1.2 및 0.070 l $mole^{-1}$이다. 이 결과와 문헌에 보고된 결과를 종합하면 이러한 錯物의 상대적 안정도가 다음 순서로 감소함을 알 수 있다. ICl>IBr>$I_2$>$Br_2$>$Cl_2$ $C_6H_5I$>$C_6H_6$>$C_6H_5Br$>$C_6H_5Cl$>$C_6H_5F$