• Title/Summary/Keyword: 리간드 효과

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Palladium(II) Complexes of Aminophosphines (I). Characterization and Synthesis of $[Pd(L)X_2] with X = Cl^-, Br^-, I^-, NCS^-$ (아미노포스핀류를 포함하는 팔라듐 (II) 착물 (제1보). $[Pd(L)X_2] (X = Cl^-, Br^-, I^-, NCS^-)$의 합성과 성질)

  • Myung-Ki Doh;Bong-Gon Kim
    • Journal of the Korean Chemical Society
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    • v.27 no.4
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    • pp.255-261
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    • 1983
  • Several new $[Pd(L)X_2]$ complexes have been prepared with aminophosphines (L) such as trans-1,2-bis[diphenylphosphino)amino]cyclohexane and 1,2-bis[(diphenylphosphino) amino] propane that contain phosphorus atom as ${\pi}$-electron acceptor, and the bond character of complexes have been investigated by means of infrared and electronic spectroscopy. It was found that thiocyanate ions are N-coordinated possibly due to the steric and electronic influence of the phosphorus atom in aminophosphines that formed seven-membered chelate rings, and that spectrochemical series that is derived from the electronic spectra of the complexes is $NCS^- > Cl^- > Br^- > I^-$

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Temperature and Ligand Effects on the Eu(Ⅲ) Emission Spectra in the Aqueous Solution (수용액에서의 Eu(Ⅲ) 착물의 형광스펙트럼에 영향을 미치는 온도 및 리간드 효과에 관한 연구)

  • Lee, In Suk;Kim, Geon
    • Journal of the Korean Chemical Society
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    • v.34 no.6
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    • pp.548-554
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    • 1990
  • Temperature effects on the fluorescence emission spectra of 0.01 M Eu(III) ion with ClO$_4$, Cl$^-$, NO$_3$ were studied. Relative intensity change of hypersensitive band ($^5D0\; {\to}\;^7F_2$) and nonhypersensitive band ($^5D0 \;{\to}\;^7F_1$) was quite remarkable with temperature and ligand. The relative intensity change was interpreted as the change of formation constant and used to calculation the enthalpy change of $Eu(H_2O)_X^{3+}$+ to EuL(H$_2O)_{X-1}^{2+}$ complex. $\Delta{H}$ of $Eu(H_2O)_X^{3+}$ to EuCl(H$_2O)_{X-1}^{2+}$ was roughly 15 kJ/mol and temperature independent, but $\Delta{H}$ of EuNO$_3(H_2O)_{X-1}^{2+}$ was changed with temperature; -11 kJ/mol at 25$^{\circ}C$ and 47 kJ/mol at 250$^{\circ}C$.

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Temperature and Ligand Effects on the Ho(Ⅲ) Absorption Spectra in Aqueous Solution (수용액에서의 Ho(III) 착물의 흡수 스펙트럼에 영향을 미치는 온도 및 리간드 효과에 관한 연구)

  • Mi Kyeong Kim;Wha-Jin Han;Seung Jun Jeon;Keon Kim
    • Journal of the Korean Chemical Society
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    • v.36 no.6
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    • pp.824-831
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    • 1992
  • Absorption spectra were observed for several Ho(III)-ligand systems in aqueous solution under the changes of ligand concentration and temperature. The intensity change of hypersensitive band $(^5I_8\;\to\;^5G_6)$ was quite remarkable with temperature and concentration, and was interpreted as the change of coordination environments. The transition intensities observed in these spectra were analyzed in terms of the Judd-Ofelt intensity parameters, $\Omega_\lambda$ ($\lambda$ = 2, 4, 6), for 4f $\to$ 4f electric dipole transitions. The $\Omega_2$ parameter was the most sensitive to the temperature and concentration. Using the changes of $\Omega_2$, $Cl^-$ and ${NO_3}^-$ ions were found to form inner sphere complexes in aqueous solution.

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알츠하이머병(Alzheimer's disease)의 신약개발을 위한 5-HT6 serotonin 수용체의 구조 예측 및 리간드 다킹(docking) 연구

  • Kim, Hyeon-Gyeong;Jo, Eun-Seong
    • Proceeding of EDISON Challenge
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    • 2017.03a
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    • pp.46-53
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    • 2017
  • 알츠하이머병은 치매를 유발하는 가장 주된 원인 질환으로 환자들은 인지장애를 겪게 된다. 현재 치료약으로 사용되는 약으로는 acetylcholinesterase 저해재가 있지만 이 약들의 효과는 미비하다. 그래서 인지기능에 영향을 미친다고 알려진 신경전달물질인 GABA, Glutamate, acetylcholine의 수치를 조절 할 수 있는 $5-HT_6$ receptor antagonist가 현재 개발되고 있다. 현재 여러 antagonist들이 임상실험 되었고, 인지 능력향상에 효과를 보이고 있다. 그러나, $5-HT_6$ receptor의 구조가 밝혀지지 않아 아직 원자적 수준의 결합 분석이 이루어지지 않았으므로 이 부분에 대한 연구가 필요하다. 따라서 본 연구에서는 Homology modeling을 통해 receptor의 구조를 예측하고, 현재 임상실험 중인 antagonist들 중 7개를 docking을 통해 단백질과 리간드의 결합을 예측하였다. Edison에서 Galaxy TBM과 Galaxy Refine을 사용하여 Homology modeling 한 결과 GPCR의 전형적인 모델에 특징적으로 긴 cterminal을 가졌다는 것을 확인 할 수 있었다. 생성된 구조를 가지고 Edison의 Dock 프로그램으로 7개의 antagonist가 어떠한 결합을 하는지 분석하였다. 그 결과, binding pose에 공통적으로 Trp102, Asp106, Val107, Pro177, Phe188, Val189, Ala192, Phe284, Phe285, Asn288, Thr306, Tyr310이 관여하는 것을 docking을 통해 알 수 있었다. 특히, Phe285는 7개의 antagonist 중에 4개와의 interaction을 하고 있는 것을 관찰하였다. 이 연구를 통하여 $5-HT_6$에 효과적으로 결합하여 치료효과를 낼 수 있는 신약을 개발할 수 있다.

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Electronic Structure and Elemental Composition of the Lead Sulfide Colloidal Quantum Dots Depending on the Types of Ligand and Post-Treatment (리간드 종류와 후처리 공정에 따른 황화납 콜로이드 양자점 박막의 전자 구조 및 원소 조성 분석)

  • Kim, Tae Gun;Choi, Hyekyoung;Jeong, Sohee;Kim, Jeong Won
    • Journal of the Korean Chemical Society
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    • v.60 no.6
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    • pp.402-409
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    • 2016
  • Thin films of lead sulfide colloidal quantum dots (CQDs) of 2.8 nm in diameter are fabricated and their surfaces are passivated by 3-mercaptopropionic acid (MPA) ligand or hybrid type ($MPA+CdCl_2$) ligand, respectively. The changes in valence band electronic structure and atomic composition of each PbS CQD film upon post-treatment such as air, N2 annealing or UV/Ozone have been studied by photoelectron spectroscopy. The air annealing makes the CQD fermi level to move toward the valence band leading to "p-type doping" regardless of ligand type. The UV/Ozone post-treatment generates $Pb(OH)_2$, $PbSO_x$ and PbO on both CQD surfaces. But the amount of the PbO has been reduced in hybrid type ligand case, especially. That is probably because the extra Pb cations in (111) surface are additionally passivated by $Cl_2$ ligand, which limits the reaction between the Pb cation and ozone.

Stability Constants for Transition Metal ions of Hexadentate $N_6$ Ligands Containing Two Pyridyl Groups (피리딘을 포함하는 여섯자리 $N_6$ 리간드와 전이금속 이온 착물의 안정도상수)

  • Kim, Sun-Deuk;Kim, Jun-Kwang;Park, Yoon-Yul
    • Analytical Science and Technology
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    • v.12 no.5
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    • pp.397-402
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    • 1999
  • The open-chain hexadentate $N_6$, ligand containing two pyridyl groups, 1,15-bis(2-pyridyl)-2,6,10,14-tetraazapentadecane (bpyped) has been synthesized as its tetrahydroehloride salt and characterized by EA, IR, NMR, and Mass. Its proton dissociation constants($logK{^n}_H$) and stability constants ($log\;K_{ML}$) for Co(II), Ni(II), Cu(II) and Zn(II) ions were determined at $25^{\circ}C$ and ionic strength 0.10 M($KNO_3$) in aqueous solution by potentiometry and compared with those or analogous $N_6$ ligands contain one or two propylenic spacers, which make six-membered chelate rings, between the aliphatic nitrogen atoms.

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Potentiometric Study of Transition Metal Ions Complexes of Hexadentate($N_4$, $O_2$) Ligands (질소-산소계 여섯 자리 리간드들의 전이금속이온 착물에 대한 전위차법 연구)

  • Kim, Sun-Deuk;Kim, Jun-Kwang;Lee, Woo-Sik
    • Journal of the Korean Chemical Society
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    • v.44 no.6
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    • pp.518-525
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    • 2000
  • The open-chain hexadentate N$_4$, O$_2$ ligands 1,13-bis(2-hydroxybenzyl)-2,5,9,12-tetraazatridecane-tetrahydrochloride (BSATD${\cdot}$4HCl) and 1,14-bis (2-hydroxybenzyl)-2,6,9,12-tetraazatetradecane-tetrahydrochloride (BSATED${\cdot}$ 4HCl) have been synthesized as their tetrahydrochloride salt and characterized by EA, IR, NMR and Mass. Their proton dissociation constants(log$K^{n}_{H}$) and stability constants(log$K_{ML}$) for Cu(II), Ni(II), Co(II), and Zn(II) ions were determined in aqueous solution by potentiometry and compared with those of analogous N$_4$, O$_2$ ligands contain ethylenic spacers or propylenic spacers, which make six-membered chelate rings between the aliphatic nitrogen atoms. Synthesis and characterization of [Cu(BSATD)]ClO$_4$ and [Cu(BSATED)](ClO$_4$)$_2$ complexes are described.

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