• Bulletin of the Korean Chemical Society
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• 제10권6호
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• pp.491-495
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• 1989

Resolution of enantiomers of DNS-amino acids has been achieved by a reversed phase liquid chromatography with an addition of a copper(Ⅱ) complex of N-benzyl-L-hydroxyproline to the mobile phase. N-Benzyl-L-hydroxyproline was prepared and used as a chiral ligand of copper(Ⅱ) chelate for the optical resolution. The pH and the concentration of copper(Ⅱ) chelate, organic solvent, and buffer agent in the mobile phase all affect the optical resolutions of dansyl amino acids. The elution orders between D and L-DNS-amino acids were different depending on the structure of the side chain of the amino acids. The retention mechanism for the chiral separation of the dansyl amino acids can be illustrated by the equilibrium of ligand exchange and by hydrophobic interaction with $C_{18}$ stationary phase. The chiral separation can be illustrated with cis and trans effect of the ligand exchange reaction.

• Bulletin of the Korean Chemical Society
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• 제15권11호
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• pp.990-996
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• 1994

New ferrocene-based chelate amines, $Fe[C_5H_4CH(Me)NMe_2]_2\;(3), \;Fe[C_5H-3(CH(Me)NMe_2)(PPh_2)-1,2]_2\;(4),\;(C_5H_5)Fe(C_5H_3(CH_2NMe_2)(CH(CN)NMe_2-1,2)\;(6),\;and\;(C_5H_5)Fe(C_5H_3(CH_2NMe_2)(CH(Me)NMe_2-1,2)$ (7) have been prepared. The reaction and the coordination chemistry of 4 and other related compounds (S,R)-(1-N,N-dimethylaminoethyl)-2-dicyclohexylphosphino)ferrocene (CPFA) and 1,1'-bis-(diphenylphosphino)ferrocene (BPPF) with $Rh_2(OAc)_4(MeOH)_2$ were investigated. The reaction of the chiral ligand (S,R)-CPFA forms a complex of the type (${\eta}^1$-(S,R)-CPFA-P)$_2Rh_2(OAc)_4$ (8) in which the ligand is coordinated to both rhodium centers in a monodentate fashion through phosphorus. In contrast, the bisphosphine analogues such as BPPF and 4 afford chelate complexes of the type (${\eta}^2-PP)Rh_2(OAc)_4$ (9 & 10) where both ligands act as a chelate bidentate to a single rhodium atom. All these complexes were characterized by microanalytical and spectroscopic techniques. In one case, the structure of 8 was determined by X-ray crystallography. Crystals are monoclinic, space group C2 (No. 5), with a=26.389 (3), b=12.942 (1), c=11.825 (1) A, ${\beta}$=111.22(1)$^{\circ}$, V=3964.7 (8) $A^3$, Z=4, and $D_{calc}$=1.58 g $cm^{-3}$. Two Rh(II) centers are bridged by four $AcO^-$ groups in the ${\eta}^1$ : ${\eta}^1$ mode across a Rh-Rh single bond, and octahedral coordination at Rh(1) and Rh(1') is completed by axially coordinating (S,R)-CPFA and a briding $AcO^-$, respectively.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1273-1276
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• 2008

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1018-1023
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• 2006

The metal chelate complex of aluminum 8-hydroxyquinolines $(Alq_3)$ is an important electro-luminescent (EL) material used in fabricating organic light emitting (OLEDs). In this work, diodes / displays using in house synthesized $Alq_3$ and simple structure have been fabricated. It is demonstrated that luminance of $12460\;cd/m^2$ and efficiency of 3.1 cd/A are achievable in these fluorescent devices. Possible degradation effects are analyzed.

• Korean Membrane Journal
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• 제10권1호
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• pp.39-45
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• 2008

Polyelectrolyte complex based on two anionic polysaccharides, composed of sodium alginate and carrageenan, were prepared by interacting with divalent calcium ions in solution. The effects of annealing on the structural deformation of polyelectrolyte complex and on their characteristics at removing water from a methanol mixture from the point of molecular sieve were investigated and discussed. The result showed that the structural deformation of the annealed polyelectrolyte complex has an effect on the free volume between these polymer chains and the chelate segments such a shrinking of the overall morphology, which act as a molecular sieve in the separation of methanol and water mixtures.

• Bulletin of the Korean Chemical Society
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• 제15권8호
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• pp.669-673
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• 1994

Coordination isomers of cis-(N-N)Pt(Glu) prepared by reaction of cis-(N-N)Pt($SO_4$) (N-N=2$NH_3$, ethylenediamine(en),(R,R)-1,2-diaminocyclohexane (DACH), N,N,N',N'-tetramethylethylenediamine (TMEDA)) with barium glutamate in water have been monitored and characterized by $^1H-NMR$, $^{13}C-NMR$, IR, and mass spectra. The reaction at room temperature affords the mixture of O,O'-and N, ${\alpha}$ O-chelated platinum(II) complexes. The O,O'-chelate initially formed isomerized to N,${\alpha}$O-chelate on standing for a long time or increasing temperature. The ratio of the two isomers at room temperature depends on the nature of the nitrogen donor coligand (N-N).

• 한국산학기술학회논문지
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• 제4권4호
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• pp.357-360
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• 2003

작약의 methanol 추출물은 혈소판 활성 실험에서 혈소판 응집에 대해 강한 억제를 보였다. 활성성분은 chromatography방법을 사용하여 정제하였고 NMR과 기존의 Data로 분석하였다. Compound 1b는 benzoyloxypaeoniflorin과 동일한 구조임을 확인하였으며. compound 2e는 작약의 주성분인 paeoniflorin과 동일한 화학구조를 가졌으며 , compound 3a의 분석결과 구조적 유사성은 있으나 동일한 구조식은 확인 할 수 없었지만 collagen에서 응집억제활성이 90％이상의 뛰어난 활성을 나타내어 benzoyloxypaeoniflorin과 유사하게 benzoyl 기가 다른 작용기로 치환되었거나 Rl group이 다른 작용기로 치환된 형태로 추측하였다. Paeoniflorin이 collagen보다 thrombin에서 강한 억제를 보이는 것은 Ca/sup 2＋/ chelate를 형성함으로 인해 calcium 대사산물이 파괴된 것으로 추측했다. Compound 3a는 paeoniflorin의 benzoyl 기에 있는 OH기나 paeoniflorin의 glycoside 5-carbon위치의 OH기 대신에 다른 작용기가 대사산물로의 역할을 수행했을 것으로 추정했다.

• 한국결정성장학회지
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• 제21권2호
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• pp.75-81
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• 2011

육방정계 구조를 가지는 수산화아파타이트 결정은 킬레이트 착화합물을 형성 할 수 있는 EDTA(ethylene diamine tetraacetic acid)를 이용하여 수열조건에서 합성 하였다. 제조된 분말은 X-선 회절 패턴 및 주사전자현미경에 의해 특성 평가 하였다. 제조된 수산화아파타이트 분말은 육방정계 구조의 c축에 따라 결정이 성장하였고, 결정의 형상은 수열온도, pH, EDTA/Ca 및 출발물질의 Ca/P 몰 비와 같은 반응 파라메타에 의해 제어 되었다.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.614-618
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• 2005

The complex of the composition LaL(N$O_3)_3\;(H_2O)_2$ is prepared by the reaction of La($NO_3)_3{\cdot}6H_2O$ with Nethylmorpholine in aqueous medium. The ligand is involved in the complex as a neutral species where the chelation occurs via the oxygen of the ligand moiety and the nitrate groups as bidentate ligand. The chemical structure of the studied complex is confirmed through IR, XRD, and thermal analysis data. The complexation equilibria of La(III) with N-ethylmopholine is studied in aqueous medium at ionic strength I = 0.1 mol${\cdot}dm^{-3}\;KNO_3$ and at 25, 35 and 45 ${^{\circ}C}$, respectively. The thermodynamic parameters $\Delta$G, $\Delta$H and $\Delta$S values were calculated to prove the association with the complex formation. It is clearly observed that the process is accompanied by absorption of heat, i.e. endothermic process, while the entropy does not change greatly attributed to the release of constant number of water molecules during chelate formation.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.577-580
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• 2006