• Bulletin of the Korean Chemical Society
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• 제18권10호
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• pp.1050-1052
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• 1997

The complexes M(CO)4-1,2-(PPh2)2-1,2-C2B10H10 (M=Cr 2a, Mo 2b, W 2c) have been prepared in good yields from readily available bis-diphenylphosphino-o-carboranyl ligand, closo-1,2-(PPh2)2-1,2-C2B10H10 (1), by direct reaction with Group Ⅵ metal carbonyls. The infrared spectra of the complexes indicate that there is an octahedral disposition of chelate bis-diphenylphosphino-o-carboranyl ligand around the metal atom. The crystal structure of 2a was determined by X-ray diffraction. Complex 2a crystallizes in the monoclinic space group P21/n with cell parameters a = 12.2360(7), b = 17.156(1), c = 16.2040(6) Å, V = 3354.1(3) Å3, and Z =4. Of the reflections measured a total of 2514 unique reflections with F2 > 3σ(F2) was used during subsequent structure refinement. Refinement converged to R1 = 0.066 and R2 = 0.071. Structural studies showed that the chromium atom had a slightly distorted pseudo-octahedral configuration about the metal center with two phosphine groups of o-carborane occupying the equatorial plane cis-orientation to each other. These metal carbonyl complexes are rapidly converted to the corresponding metal carbene complexes, [(CO)3M=C(OCH3)(CH3)]-1,2-(PPh2)2-1,2-C2B10H10 (M= Cr 3a, Mo 3b, W 3c), via alkylation with methyllithium followed by O-methylation with CF3SO3CH3.

• Bulletin of the Korean Chemical Society
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• 제12권4호
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• pp.371-373
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• 1991

The crystal structure of eprazinone dihydrochloride, $C_{24}H_{32}N_2O_2$${\cdot}$2HCl, has been determined from 2102 independent reflections collected on an automated Nonious CAD-4 diffractometer using graphite-monochromated $Mo-K\alpha$ radiation. The crystals are monoclinic, space group P$2_1$/n, with unit cell dimensions a=11.381(2), b=28.318(2), c=7.840(1) $\AA$, $\beta=92.45(2)^{\circ}$, ${\mu}=2.37$ c$m^{-1}$, F(000)=968, and Z=4. Final R value is 0.071 for independent 2102 observed reflections. The molecule assumes an extended conformation. The piperazine ring has a normal chair conformation and the four carbon atom are planar with a maximum displacement of 0.004 $\AA$ for C(18) atom. The two chloride ions are hydrogen bonded to the two piperazine nitrogen atoms [N(14)${\cdot}{\cdot}{\cdot}$Cl(1); 2.986(6) $\AA$ N(17)…Cl(2); 3.084(8) $\AA$].

• Bulletin of the Korean Chemical Society
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• 제19권5호
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• pp.527-530
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• 1998

This paper presents the electrochemistry and molecular orbital (MO) picture of a series of conformationally-restricted thioxantone derivatives. A series of $C_2-substituted$ thioxanthones were examined to probe the electronic influence of the substituent on the electrooxidation and electroreduction sites (i.e., on the electron densities at the 10-and 9-positions), respectively. In the presence of "electrophoric" groups such as C=O and S, characteristic electrochemical reduction and oxidation responses are observed. The electrochemical reaction was diffusion-controlled, because the $I_p/{\upsilon}^{1/2}$ ratio was constant for the anodic and cathodic wave of thioxantone derivatives. These substituent effects are presented in terms of correlations of oxidation (or reduction) potentials with the highest occupied molecular orbital (HOMO), or lowest unoccupied molecular orbital (LUMO) energies, respectively. There is good correlation between energies of the HOMO vs. $E_{pa}^{(+)}$ and energies of the LUMO vs. $E_{pc}^{(-)}$. Frontier Molecular Orbital (FMO) is changed by the functional group of thioxanthones. FMO energy level was offered us the information about the electron transfer direction, and the coefficient of FMO was offered the information about the electron transfer position. Sulfur atom has an important effect on oxidation potential, $E_{pa}^{(+)}$ and the carbonyl carbon has an important effect on reduction potential, $E_{pc}^{(-)}$. Therefore we were appreciated that the contribution of sulfur atom for the $E_{pa}^{(+)}$ and HOMO energies is larger than the contribution of carbonyl group for the $E_{pc}^{(-)}$ and LUMO energies.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3229-3240
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• 2023

Due to neutron radiation, atomic displacement has a significant effect on material in nuclear reactors. A range of secondary displacement models, including the Kinchin-Pease (K-P), Lindhard, Norgett-Robinson-Torrens (NRT), and athermal recombination-corrected displacement per atom (arc-dpa) have been suggested to calculate the number of displacement per atom (dpa). As neutron elastic interaction is the main cause of displacement damage, the focus of the current study is to calculate the atomic displacement caused by the neutron elastic interaction in order to estimate the exact amount of yield strength in a WWER-1000 reactor pressure vessel. To achieve this purpose, the reactor core is simulated by MCNPX code. In addition, a program is developed to calculate the elastic radiation damage induced by the incident neutron flux (RADIX) based on different models using Fortran programming language. Also, due to non-elastic interaction, the displacement damage is calculated by the HEATR module of the NJOY code. ASME E-693-01 standard, SPECTER, NJOY codes, and other pervious findings have been used to validate RADIX results. The results showed that the RADIX(arc-dpa)/HEATR outputs have appropriate accuracy. The relative error of the calculated dpa resulting from RADIX(arc-dpa)/HEATR is about 8% and 46% less than NJOY code, respectively in the ¼ and ¾ vessel wall.

• 대한화학회지
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• 제21권3호
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• pp.161-170
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• 1977

Glycine (또는 glycino 음이온)과 styrene을 리간드로 하는 백금(II) 착물이 합성되었다. 적외선 분광법에 의하면 N-트란스 이성체에서는 킬레이트를 이루는 glycine음이온의 질소원자가 styrene에 대하여 트란스 위치에 있음이 확인되었다.

• Bulletin of the Korean Chemical Society
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• 제12권4호
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• pp.438-440
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• 1991

Each aqueous solution (pH = 1) of acetic acid, acetamide, and acetonitrile produces carbon dioxide and hydrogen at 300 K when irradiated in the presence of semiconductors such as titanium dioxide, platinized titanium dioxide, etc. Similar results were obtained for each of benzoic acid, benzamide, and benzonitrile. Based on the relative amount of carbon dioxide, nitrile is believed to be transformed into carboxylic acid through the intermediacy of amide. A mechanism in which hydrogen atom and hydroxyl radical are involved is presented.

• Bulletin of the Korean Chemical Society
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• 제20권12호
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• pp.1433-1436
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• 1999

The 2-(2,4-dimethoxyphenyl)-4-MDO (2) underwent polymerization with ring opening as well as cyclization reaction in the presence of various cationic catalysts such as boron trifluoride, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid and trifluoroacetic acid. They afforded a mixture of the ring-opened poly(keto ether) and 3(2H)-dihydrofuranone derivative. Both the methylene group and oxygen atom of 1,3-dioxolane ring were participated in the reaction with cationic catalyst. The contents of the polymer and cyclization product were variable according to the acid strength of the cationic catalysts.

• 대한수학회보
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• 제58권2호
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• pp.365-384
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• 2021

Let A be an expansive dilation on ℝn, and p(·) : ℝn → (0, ∞) be a variable exponent function satisfying the globally log-Hölder continuous condition. Let Hp(·)A (ℝn) be the variable anisotropic Hardy space defined via the non-tangential grand maximal function. In this paper, the author obtains the boundedness of anisotropic convolutional ��-type Calderón-Zygmund operators from Hp(·)A (ℝn) to Lp(·) (ℝn) or from Hp(·)A (ℝn) to itself. In addition, the author also obtains the duality between Hp(·)A (ℝn) and the anisotropic Campanato spaces with variable exponents.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.306-310
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• 2003

Hydrolysis reactions of S-phenyl-S-vinyl-N-p-tosylsulfilimine (VSI) and its derivatives at various pH have been investigated kinetically. The hydrolysis reactions produced phenylvinylsulfoxide and p-toluene sulfonamide as the products. The reactions are first order and Hammett ρ values for pH 1.0, 6.0, and 11.0 are 0.82, 0.45, and 0.57, respectively. This reaction is not catalyzed by general base. The plot of k vs pH shows that there are three different regions of the rate constants $(k_t)$ in the profile.; At pH < 2 and pH > 10, the rate constants are directly proportional to the concentrations of hydronium and hydroxide ion catalyzed reactions, respectively. The rate constant remains nearly the same at 2 < pH < 10. On the bases of these results, the plausible hydrolysis mechanism and a rate equation have been proposed: At pH < 2.0, the reaction proceeds via the addition of water molecule to sulfur after protonation at the nitrogen atom of the sulfilimine, whereas at pH > 10.0, the reaction proceeds by the addition of hydroxide ion to sulfur directly. In the range of pH 2.0-10.0, the addition of water to sulfur of sulfilimine appears to be the rate controlling step.

• 대한의생명과학회지
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• 제1권1호
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• pp.89-94
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• 1995

B(a)P와 cytochrome P-450의 heme부분은 구조가 평면이므로 겹침 상호작용이 가능하다. 가능성이 큰 겹침 상호작용모형을 결정하기 위해 이들 분자에 대해 MO계산을 행하였다. 이 경우 궤도함수 상호작용이 가장 중요하므로, 프론티어궤도함수의 eigen vetor값이 크며 상호 결합성을 보여야 한다. 이를 바탕으로 다섯가지 가능성이 있는 모형을 선택한 수 MN2와 MO방법을 실행하였다. 이중 B(a)P의 4, 5, 6번 위치와 heme group의 Y탄소와 III pyrrole환이 포개어지는 형태가 가장 안전하였다.