http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Yang, Kiyull,Park, Young Hee,Cho, Soo Gyeong,Lee, Hai Whang,Kim, Chan Kyung,Koo, Hyun-Joo Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of computational chemistry Vol.31 No.13
<P>To develop new highly energetic materials, we have considered the design of molecules with high nitrogen content. Possible candidates include 1,3,5-triazine derivatives. In this work, we studied potential synthetic routes for melamine using the MP2/6-31+G(d,p)//B3LYP/6-31G(d) level of theory. The mechanisms studied here are stepwise mechanism beginning with the dimerization of cyanamide and one-step termolecular mechanism. The same type of mechanism is also applied to nitro-substituted 1,3,5-triazines. Values for the heat of formation in the solid phase were predicted from density functional theory calculations. Densities were estimated from a regression equation obtained by molecular surface electrostatic potentials. The Cheetah program was used to study the explosive performance of these compounds. In this study, we found that the explosive properties of 2-amino-4, 6-dinitro-1, 3,5-triazine (ADNTA), and 2,4,6-trinitro-1,3,5-triazine (TNTA) are similar to those of RDX and HMX, respectively. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010</P> <B>Graphic Abstract</B> <P> <img src='wiley_img_2010/01928651-2010-31-13-JCC21542-gra001.gif' alt='wiley_img_2010/01928651-2010-31-13-JCC21542-gra001'> </P>
Hydration of acetone in the gas phase and in water solvent
Yang, Kiyull,Hsieh, Yih-Huang,Kim, Chan-Kyung,Zhang, Hui,Wolfe, Saul Canadian Science Publishing 2010 Canadian journal of chemistry Vol.88 No.1
<P> In water solvent, the hydration of acetone proceeds by a cyclic (cooperative) process in which concurrent C-O bond formation and proton transfer to oxygen take place through a solvent and (or) catalyst bridge. Reactivity is determined primarily by the concentration of a reactant complex and not the barrier from this complex. This situation is reversed in the gas phase; although the concentrations of reactive complexes are much higher than in solution, the barriers are also higher and dominant in determining reactivity. Calculations of isotope effects suggest that multiple hydron transfers are synchronous in the gas phase to avoid zwitterionic transition states. In solution, such transition states are stabilized by solvation and hydron transfers can be asynchronous. </P>
Stoichiometric Solvation Effects. Solvolysis of Trifluoromethanesulfonyl Chloride
구인선,Kiyull Yang,Jong Kuen Park,Mi Young Woo,Jun Mi Cho,Jong Pal Lee,Ikchoon Lee 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.8
Solvolyses of trifluoromethanesulfonyl chloride (TFMSC) in water and in aqueous binary mixtures of acetone, ethanol and methanol are investigated at 25, 35 and 45 oC. The Grunwald-Winstein plot of first-order rate constants for the solvolytic reaction of TFMSC with YCl (based on 2-adamantyl chloride) shows marked dispersions into three separate curves for three aqueous mixtures. The extended Grunwald-Winstein plots for the solvolysis of TFMSC show better correlation. The large negative S ¹ and relatively small positive H ¹ reveals that the solvolytic reaction proceeds via a typical bimolecular reaction mechanism. The l and m values determined in various solvents are consistent with the proposed mechanism of the general base catalysis SAN/SN2 reaction mechanism for TFMSC solvolyses based on mass law and stoichiometric solvation effect studies.
Solvolysis Reaction Kinetics, Rates and Mechanism for Phenyl N-Phenyl Phosphoramidochloridate
Choi, Hojune,Yang, Kiyull,Koh, Han Joong,Koo, In Sun Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.8
The rate constants of solvolysis of phenyl N-phenyl phosphoramidochloridate (PhNHPO(Cl)OPh, Target Compound-TC1) have been determined by a conductivity method. The solvolysis rate constants of TC1 are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and YCl solvent ionizing scale, and sensitivity values of $0.85{\pm}0.14$ and $0.53{\pm}0.04$ for l and m, respectively. These l and m values were similar to those obtained previously for the complex chemical substances dimethyl thiophosphorochloridate; N,N,N',N'-tetramethyldiamidophosphorochloridate; 2-phenyl-2-ketoethyl tosylate; diphenyl thiophosphinyl chloride; and 9-fluorenyl chloroformate. As with the five previously studied solvolyses, an $S_N2$ pathway is proposed for the solvolyses of TC1. For four representative solvents, the rate constants were measured at several temperatures, and activation parameters (${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$) were estimated. These activation parameters are also in line with the values expected for an $S_N2$ reaction.
고리형 헥사펩티드의 형태 및 5,5-디페닐하이덴토인에 의한 양이온 전달방해에 관한 이론적 연구
양기열,구인선,이익춘,손창국,Kiyull Yang,In Sun Koo,Ikchoon Lee,Chang-Kook Sohn 대한화학회 1992 대한화학회지 Vol.36 No.4
ECEPP/2 및 MM2 방법을 이용하여 고리형 헥사펩티드의 형태 및 알칼리 금속 양이온과의 착물형성 그리고 DPH에 의한 양이온 전달방해를 이론적으로 살펴보았다. 착물을 형성하지 않은 고리형 펩티드에 대하여 여러 가지 안정한 형태가 얻어졌으며, 대부분의 아미드 수소원자는 카르보닐 산소와 분자내 수소결합을 이루고 있어 조밀한 구조를 나타내었다. 펩티드와 Na$^+$ 이온 및 DPH간의 착물형성에너지는 각각 -60kcal/mol 및 -18kcal/mol이었다. 그러나 헥사펩티드의 국부최소에너지 구조들에는 금속 양이온을 결합할 수 있는 공동이 존재하지 않았고 공동이 존재하는 헥사펩티드의 에너지는 본 연구의 최저에너지 구조보다 10kcal/mol 정도 높은 에너지를 주었으며, 이러한 에너지 차이와 금속 양이온의 탈수 과정을 고려하면 DPH에 의한 양이온 전달방해를 설명할 수 있었다. 또한 DPH와 결합하는데 있어서의 가장 중요한 아미노산 잔기는 글리신이었으며 이를 사코신(N-메틸 글리신) 으로 치환할 때 양이온 전달이 저해되는 실험적 사실을 설명할 수 있었다. The conformations of hexapeptides, their complexation with alkali cations and the inhibition of the cation transport by 5,5-diphenylhydantoin(DPH) were studied theoretically using ECEPP/2 and MM2 force field. Several low energy conformations of uncomplexed cyclic hexapepides are obtained, and they adopt compact conformations in which most amide hydrogens form intramolecular hydrogen bond to amide carbonyl oxygens. The complexation energy of the peptide with $Na^+$ ion and DPH is -60 kcaal/mol and -18 kcal/mol, respectively. However, no suitable cavity to bind metal cation exists for the local minima of the peptide, and the internal energy of the uncomplexed hexapeptide having cavity is higher than that of the uncomplexed global minimum of this work by 10 kcal/mol. Also, one of the most important amino acid residue to bind DPH is Glycine, and this can explain experimental observation that the replacement of Gly by Sarcosine (N-methyl Glycine) reduce the inhibition ability of the cation transport.
Oh, Hyunjung,Choi, Hojune,Park, Jong Keun,Yang, Kiyull,Koo, In Sun Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.9
The solvolysis rate constants of piperonyloyl chloride (1) in 27 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale, $Y_{Cl}$ solvent ionizing scale, and I aromatic ring parameter with sensitivity values of $0.30{\pm}0.05$, $0.71{\pm}0.02$, and $0.60{\pm}0.04$ for l, m, and h, respectively. The solvent kinetic isotope effect values (SKIE, $k_{MeOH}/k_{MeOD}$ and $k_{50%MeOD-50%D2O}$) of 1.16 and 1.12 were also in accord with the values for the $S_N1$ mechanism and/or the dissociative $S_N2$ mechanism. The product selectivity values (S) for solvolysis of 1 in alcohol/water mixtures were in the range of 0.5 to 1.9, which is also consistent with the proposed unimolecular ionization mechanism.