• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
• /
• pp.149-149
• /
• 2006

• Bulletin of the Korean Chemical Society
• /
• 제35권6호
• /
• pp.1754-1758
• /
• 2014

The nucleophilic substitution reactions of bis(Y-aryl) chlorothiophosphates (1) with X-pyridines are investigated kinetically in acetonitrile at $35.0^{\circ}C$. The free energy relationships with both X and Y are biphasic concave upwards with a break point at X = 3-Ph and Y = H, respectively. The sign of cross-interaction constants (CICs; ${\rho}_{XY}$) is positive with all X and Y. Proposed mechanism is a stepwise process with a rate-limiting leaving group departure from the intermediate with all X and Y. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorothiophosphates (2). In the case of Y = electron-withdrawing groups, the cross-interaction between Y and Y, due to additional substituent Y, is significant enough to change the sign of ${\rho}_{XY}$ from negative with 2 to positive with 1, indicative of the change of mechanism from a rate-limiting bond formation to bond breaking.

• Bulletin of the Korean Chemical Society
• /
• 제34권3호
• /
• pp.743-748
• /
• 2013

The temperature dependence of the partition coefficients of a neuropeptide, substance P (SP), in isotropic acidic bicelles was investigated by using a pulsed field gradient nuclear magnetic resonance diffusion technique. The addition of negatively charged dimyristoylphosphatidylserine to the neutral bicelle changed the SP partitioning a little, which implies that the hydrophobic interaction between the hydrophobic residues of SP and the acyl chains of lipid molecules is the major interaction while the electrostatic interaction is minor in SP binding in a lipid membrane. From the temperature dependence of the partition coefficients, thermodynamic functions were calculated. The partitioning of SP into the acidic bicelles is enthalpy-driven, as it is for small unilamellar vesicles and dodecylphosphocholine micelles, while peptide partitioning into a large unilamellar vesicle is entropy-driven. This may mean that the size of lipid membranes is a more important factor for peptide binding than the surface curvature and surface charge density.

• Bulletin of the Korean Chemical Society
• /
• 제32권9호
• /
• pp.3429-3432
• /
• 2011

Distribution diagram of $FeCl_2$ in HCl solution indicated that $FeCl^+$ was a predominant species in strong HCl solution up to 10 M. Solvent extraction of $FeCl_2$ has been performed in the HCl concentration range from 5 to 9 M by using Alamine336 as an extractant. Interaction parameter of $FeCl^+$ for Bromley equation was estimated from our solvent extraction data. This parameter thus obtained in our study can be employed in calculating the activity coefficient of $FeCl^+$ in high concentration of HCl.

• Bulletin of the Korean Chemical Society
• /
• 제29권4호
• /
• pp.736-740
• /
• 2008

The interaction of myelin basic protein (MBP) from bovine central nervous system with divalent calcium ion was studied by isothermal titration calorimetry at 27 ${^{\circ}C}$ in aqueous solution. The extended solvation model was used to reproduce the enthalpies of $Co^{2+}$-MBP interaction over the whole $Co^{2+}$ concentrations. The solvation parameters recovered from the solvation model were attributed to the structural change of MBP due to the metal ion interaction. It was found that there is a set of three identical and noninteracting binding sites for $Co^{2+}$ ions. The association equilibrium constant is 0.015 ${\mu}M^{-1}$. The molar enthalpy of binding is $\Delta$H = −14.60 kJ $mol^{-1}$.

• Bulletin of the Korean Chemical Society
• /
• 제30권6호
• /
• pp.1262-1266
• /
• 2009

Thermodynamics of the interaction between Cerium (III) chloride, $Ce^{3+}$, with Human Serum Albumin, HSA, was investigated at pH 7.0 and $27\;{^{\circ}C}$ in phosphate buffer by isothermal titration calorimetry. Our recently solvation model was used to reproduce the enthalpies of HSA interaction by $Ce^{3+}$. The solvation parameters recovered from our new model, attributed to the structural change of HSA and its biological activity. The interaction of HSA with $Ce^{3+}$ showed a set of two binding sites with negative cooperativity. $Ce^{3+}$ interacts with multiple sites on HSA affecting its biochemical and biophysical properties.

• 대한화학회지
• /
• 제20권5호
• /
• pp.364-373
• /
• 1976

多原子分子內의 內部廻轉子上에 있는 磁氣核은 分子의 全體廻轉으로 因하여 생기는 磁氣場뿐만 아니라 內部廻轉에 基因하는 磁氣場과도 相互作用할 수 있다. 이 論文에서는 多原子分子內의 內部廻轉子上에 있는 核스핀에 對한 스핀-廻轉相互作用 Hamiltonian을 誘導하였다. 誘導된 Hamiltonian은 스핀과 全體廻轉間의 相互作用을 나타내는 部分 및 스핀과 內部廻轉間의 相互作用을 나타내는 部分과의 合으로 이루어져 있음을 밝혔다. 스핀-廻轉相互作用 tensor와 磁氣的 가리움效果 間의 關係도 또한 調査하였다.

• 대한화학회지
• /
• 제34권6호
• /
• pp.539-547
• /
• 1990

DNA base인, Adenine, Guanine 그리고 Cytosine과 diaminecytosineplatinum(DCP)의 상호작용을 SC-MEH 방법에 의하여 계산한 결과, DNA base와 DCP 결합력의 크기는 guanine > adenine > cytosine임을 알 수 있었고, cis-백금(II)착물이 trans-백금(II) 착물보다 안정화에너지가 더 크게 나타남을 adenine-DCP 착물계에서 볼 수 있었다. DNA bases ring의 atomic charge는 백금(II)착물의 배위에 의해 많은 charge 변화가 있음을 관찰하였고, 이 효과에 의하여 백금(II)착물의 항암성 메카니즘을 설명할 수 있었다.

• Bulletin of the Korean Chemical Society
• /
• 제25권6호
• /
• pp.829-832
• /
• 2004

The pure product of 2,3-diaminophenazine was prepared by the enzyme-catalyzed reaction of ophenylenediamine-$H_2O_2$-horseradish peroxidase and characterized by UV/Vis spectroscopy, IR spectroscopy and NMR spectroscopy. The electrochemical behaviour of 2,3-diaminophenazine on the glassy carbon electrode was studied. The interaction between 2,3-diaminophenazine and deoxyribonucleic acid was studied by cyclic voltammetry method and UV/Vis spectroscopy, which indicated that the interaction between them is intercalation. The influence of reacting time was also studied. The binding ratio of the 2,3-diaminophenazine-DNA complex is calculated to be 1 : 2 and the binding constant is to be $5.07{\times} 10^3L{\cdot}mol^{-1}$ at room temperature.

• 대한화학회지
• /
• 제53권6호
• /
• pp.663-670
• /
• 2009

논랜덤 혼합의 2-성분 격자용액에서 특정상호작용을 갖는 경우의 수에 대한 분포를 난수 모의실험을 통하여 구하였다. 이 분포로부터 2-성분격자용액의 과잉깁스에너지 $G^E$에 대한 근사식을 유도하였다. 이 식을 사용하여 15개의 2-성분용액에 대한 일정압력에서의 액체-증기 상평형 계산을 하였고 Wilson식, Van Laar식, Redlich-Kister식의 계산 결과와 비교하여 보았다.