• 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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• 제31권8호
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• pp.2201-2206
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• 2010

To improve the separation property and stability of metal chelate Cu(II) column, three new kinds of multidentate aminocarboxy silica columns with cation-exchange properties were synthesized using glutamic acid (Glu), glutamic acidbromoacetic acid (Glu-BAA), glutamic acid-bromosuccinic acid (Glu-BSUA) as ligands and silica gel as matrix. The standard proteins were separated with prepared chromatographic columns. The stationary phases exhibited the metal chelate property after fixing copper ion (II) on the synthesized multidentate ligand silica columns. The binding capacity of immobilized metal ion was related with the dentate number of multidentate ligands. Chromatographic behavior of proteins and the leakage of immobilized metal ion on multidentate chelate Cu(II) columns were affected by the dentate number of multidentate ligands and competitive elution system directly. The results showed that quinquedentate Glu-BSUA-Cu(II) column exhibited better chromatographic property and stability as compared with tridentate Glu-Cu(II) column, tetradentate Glu-BAA-Cu(II) column and commonly used IDA-Cu(II) column.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.280-285
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• 1992

Enantiomeric separation of free amino acids has been achieved by a reversed phase liquid chromatography with addition of a Cu(Ⅱ) complex of N-alkyl-L-proline (alkyl: propyl, pentyl or octyl) to the mobile phase. The amino acids eluted were detected by a postcolumn OPA system. N-alkyl-L-proline was prepared and used as a chiral ligand of Cu(Ⅱ) chelate for the enantiomeric separation. The concentration of the Cu(Ⅱ) chelate, the organic modifier and pH affect the enantiomeric separation of free amino acids. The retention behaviour, varied with change in pH and the concentration of the Cu(Ⅱ) chelate, was different compared with those of the derivatized amino acids. The elution orders between D- and L-forms were consistent except histidine showing that L-forms elute earlier than D-forms. The retention mechanism for the enantiomeric separation can be illustrated by the stereospecificity of the ligand exchange reaction and the hydrophobic interaction between the substituent of amino acids and reversed phase, $C_18$.

• 약학회지
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• 제17권4호
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• pp.235-243
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• 1973

Determinations of the compositioin ofl chinoform metal chelates by elemental analysis and molar ratio method showed that the ratios of the ligand to metals in chinoform Cu(II) chelate, chinofrm Ni (II) chelate, and chinoform CO(II) chelate were 2:1 respectively and that the ratio in chinoform Fe(III) chelate was 3:1. It was found that diffe rential thermal values vary with the center metalic ions and that the thermal stability was in anorder of Fe>Cu>Co>Ni. The indices of over-all stability constant of chinoform Cu(II) chelate, Ni(II) chelate, Co(II) chelate, and Fe(III) chelate were 15.57, 15.16, 15.40 and 20.76, respectively, and the over-all stability was in an order of Fe>Cu>Co>Ni. The tests of the natibacterial activity in vitro of the chinoform metal chelates against Staphylococcus aureus ATCC G538, Pseudomonas aeruginosa 2131, Serratia marcescens 3357, Klebsiella pneumoniae 8899, Enterococcus 3309, Streptococcus pyogenes 507, and Escherichia coli 125 showed that the Cu(II) chelate generally had greater activity than chinoform, that it had four-fold activity particularly against Streptococcus pyogenes 507 and Staphylococcus awreus ATCC 6538, that the Ni(II) and Co(II) chelates had almost same activity, and that the Fe chelate had strong activity against Escherichia coli 125.

• 약학회지
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• 제15권2호
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• pp.41-52
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• 1971

Cu(II) chelates of several sulfanilamide derivatives (Sulfa-Cu) were prepared and their effects on solubility, absorptivity in intestinal lumen, biding tendency with serum protein and erythrocytes, concentration in rabbit blood, and acetylation rate were studied in comparison with their free ligand forms. For solubility concerned, the partition coefficients of Sulfa-Cu are decreased as following order: Sulfadimethoxine Copper chelate (SDM-Cu), Sulfamethoxypyridazine Copper chelate (SD-Cu), Sulfamerazine Copper chelate (SM-Cu), Sulfaisoxazole Copper chelate (SIX-Cu). The partition coefficients of SDM-Cu and ST-Cu were much greater than those of ligands. this phenomenone acounts for the rapid absorption of SDM-Cu and ST-Cu in the rat small intestine (in situ). The Sulfa-Cu were absorbed at the intestinal lumen of a rat in the rate of first order and there was no difference between long acting sulfa drugs and their Cu0chelates in biological half lives. In binding experiments, sulfa-Cu binded with serum protein in lower ratio than their ligands except SIX-Cu. On other hand, acetylation rates of sulfa-Cu were higher than those of free sulfa drugs and the acetylation rate were higher than those of free sulfa drugs and powder. In a experiment on Sulfa-Cu concentration in rabbit blood, the half lives of SD-Cu, SIX-cu, ST-Cu, and SM-Cu were longer than those of their ligands. Above all, the half life of SD-Cu appeared to be approximately 3.5 times logner than that of corresponding ligand, SD. When absorption of sulfa drugs or sulfa-Cu at the small intestinal lumen of a rat and the concentration in rabbit blood after absorption were compared, it was found that there was not always conrrelated.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.590-594
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• 2011

An aminocarboxy aspartic acid-bonded silica (Asp-Silica) stationary phase was synthesized using L-aspartic acid as ligand and silica gel as matrix. The standard protein mixtures were separated with prepared chromatographic column. The effects of solution pH, salt concentration and metal ion on the retention of proteins were examined, and also compared with traditional iminodiacetic acid-bonded silica (IDA-Silica) column. The results show that Asp-Silica column exhibited an excellent separation performance for proteins. The retention of proteins on Asp-Silica stationary phase was consistent with electrostatic characteristic of cation-exchange. The stationary phase displayed typical metal chelate property after fixing copper ion (II) on Asp-Silica. Under competitive eluting condition, protein mixtures were effectively isolated. Asp ligand showed better ion-exchange and metal chelating properties as compared with IDA ligand.

• 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.

• 대한화학회지
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• 제29권4호
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• pp.372-381
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• 1985

치환 8-퀴놀린올의 옥소몰리브덴(V)착물을 합성하고 착물의 원소분석, 자외선스펙트럼, 전자스펙트럼 및 전도도를 측정하였고 옥소몰리브덴(VI)착물과 함께 질량분석을 행하여 비교 검토하였다. 옥소몰리브덴(V) 착물은 비전해질이고 몰리브덴-산소의 신축진동은 $940cm^{-1}$ 부근에서 강한 흡수띠가 나타나고 결정장전이와 전하이동 전이가 일어났다. 질량분석 결과로 Mo(V, VI)착물에서 몰리브덴과 리간드의 조성이 1:2임을 확인할 수 있었고 옥소몰리브덴(VI)착물에서는 1:1조성의 착물의 질량수가 나타나지만 옥소몰리브덴(V)에서는 일부만 확인되었다.

• Bulletin of the Korean Chemical Society
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• 제7권1호
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• pp.45-50
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• 1986

Separation of optical isomers of some derivatives of amino acids by reversed-phase HPLC has been accomplished by adding a chelate of an optically active amino acid to copper(Ⅱ) to the mobile phase. Cu(Ⅱ) complexes of L-proline and L-hydroxyproline in the mobile phase showed different degrees of separation. Optical isomers of DNS derivatives of amino acids are selectively separated, but those of several other derivatives are not at all. The kinds of buffer agents, the pH, and the concentrations of acetonitrile and the Cu(Ⅱ) ligand all affect the separations. The elution behavior between D and L DNS-amino acids appears to depend on the alkyl side chain of the amino acids. A chromatographic mechanism is proposed that is based on a stereospecificity of the formation of ternary complexes by the D, L-DNS-amino acids and the chiral additive associated with the stationary phase. The steric effects of the ligand exchange reactions are related with the feasibility of cis and/or trans attack of the amino acids to the binary chiral chelate retained on the stationary phase.

• Journal of Ceramic Processing Research
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• 제21권5호
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• pp.515-523
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• 2020

Since chelating chemical had focused for enhancing bio-susceptibility and ability for the binding with biomaterials, in this study, Nitrilotiriacetic acid (NTA) was utilized for the developing chelate ligand attached superparamagnetic nanoparticle. In order to conjugate NTA, carboxylic group was needed on the surface of substrate particle for building peptide bond with amine group which was branched from the NTA structure. Therefore Fe₃O₄ nanoparticle was functionalized with various of amine precursor (Polyethyleneimine (PEI), (3-Aminopropyl)triethoxysilane (APTES)), and carboxyl precursor (Polyacrylic acid (PAA)) before the conjugation of NTA. Then NTA conjugation behavior was estimated which is varied with the type of amine precursor which affects to the surface properties.