• YAKHAK HOEJI
• /
• v.26 no.1
• /
• pp.9-23
• /
• 1982

The structure of 1-butyl-3-sulfanyl urea, ($C_{11}H_{17}N_{3}O_{3}S$) carbutamide has been determined from 575 significant independent reflections collected on an automated four-circle diffractometer. The crystals are orthorhomic, space group, $P2_{1}2_{1}2_{1}$, Z=4, with unit cell dimensions a=9.257 (2), b=9.928 (2), c=15.287 (3)${\AA}$. The structure was solved by the direct methods and refined by least-squares procedure to a final R value of 0.062. Features of the structure include layers of molecules joined by N-H....O hydrogen bond distances ranging from 2.745 to 3.100${\AA}$ involved in a bifurcated hydrogen bond across two fold screw along a and b axes. The atoms forming the urea system are essentially planar.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.9
• /
• pp.1588-1590
• /
• 2007

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1494-1502
• /
• 2013

Energy flow and C-$H_{methyl}$ and C-$H_{ring}$ bond dissociations in vibrationally excited toluene in the collision with $N_2$ and $O_2$ have been studied by use of classical trajectory procedures. The energy lost by the vibrationally excited toluene upon collision is not large and it increases slowly with increasing total vibrational energy content between 5,000 and 45,000 $cm^{-1}$. Intermolecular energy transfer occurs via both of V-T and V-V transfers. Both of V-T and V-V transfers increase as the total vibrational energy of toluene increases. When the total energy content $E_T$ of toluene is sufficiently high, either C-H bond can dissociate. The C-$H_{methyl}$ dissociation probability is higher than the C-$H_{ring}$ dissociation probability, and that in the collision with $N_2$ is larger than with $O_2$.

• Journal of the Korean Chemical Society
• /
• v.17 no.3
• /
• pp.169-173
• /
• 1973

The tridentate schiff base ligand, salicyliden amino-o-hydroxy benzene, has derived from salicylaldehyde and o-amino phenol. This ligand reacts with a series of Mo (VI), Mo (V), Mo (IV), and Mo (III) oxidated states and forms a new complexes; [Mo O$_2(H_2O)\;(C_{13}H_9O_2N)]$, [MoO Cl$(H_2O)\;(C_{13}H_9O_2N)]$, [Mo(SCN)$_2(H_2O)\;(C_{13}H_9O2_N)]$ 및 $[Mo(H_2O)_2\;(C_{13}H_9O_2N)]_2O$. The Mo (VI), Mo(V) and Mo(Ⅳ) ions in these complexes are octahedron, hexa coordinate, and the mole ratio of these ions to the ligand are 1 : 1, but Mo (III) Complex is a Mo-O-Mo oxygen bridge bond and polynuclear, and the mole ratio of Mo (III) to the ligand 1 : 1 above facts are identified from the data of Infrared spectra, visible spectra, and elemental analysis.

• The Korean Journal of Ceramics
• /
• v.6 no.4
• /
• pp.339-342
• /
• 2000

In the present study, we attempted to apply DV-X$\alpha$ method to expressing the reactivity of materials. The expression of reactivity was discussed by comparison between ${\gamma}$-C$_2$G having hydraulic activity and ${\gamma}$-C$_2$S not having hydraulic activity at normal conditions. It was found that the model cluster used for calculation can finely reproduce the bulk and surface states using with and without point charge, respectively. The hydration state was also represented by placing OH￣ on the surface of the cluster. It was calculated that the bond strength of the first layer (as surface) was bigger than that of inner layers (as bulk) for ${\gamma}$-C$_2$S while that of the first layer for ${\gamma}$-C$_2$G was smaller than that of inner layers. Subsequently a model in which OH￣ is coordinated on Ca at the surface was also calculated. The bond strength with OH￣ was stronger than that without OH￣, while for ${\gamma}$-C$_2$G the bond strength with OH￣ was weaker than that without OH￣. From these results, it is concluded that the hydraulic activity depends on whether the bond strength for hydrated state becomes weaker than that unhydrated state or not.

• Analytical Science and Technology
• /
• v.20 no.5
• /
• pp.448-451
• /
• 2007

A new bis(dicyclohexylammonium) chromate dihydrate complex, $[(C_6H_{11})_2NH_2]_2[CrO_4]{\cdot}2H_2O$, (I), has been synthesized and its structure analyzed by FT-IR, EDS, elemental analysis, ICP-AES, and single crystal X-ray diffraction methods. The Cr(VI) complex (I) is tetragonal system, I${\bar{4}}$2d space group with a = 12.5196(1), b = 12.5196(1), c = $17.3796(3){\AA}$, a = ${\beta}$ = ${\gamma}$ = $90^{\circ}$, V = $2724.09(6){\AA}^3$, Z = 4. The crystal structure of complex (I) consists of tetrahedral chromate $[CrO_4]^{2-}$ anion, two organic dicyclohexylammonium $[(C_6H_{11})_2NH_2]^+$ cations and two lattice water molecules. The chromate anion and protonated dicyclohexylammonium cation is mainly constructed through the ionic bond. The cyclohexylammonium rings of the dicyclohexylammonium cation take the chair form and vertical configuration with each other. The N-H${\cdot}$O and O-H${\cdot}$O hydrogen bond networks between the $N_{dicyclohexylammonium}$, $O_{water}$ and $O_{chromate}$ atom lead to self-assembled molecular conformation and stabilize the crystal structure.

• Journal of the Korean Vacuum Society
• /
• v.21 no.2
• /
• pp.78-85
• /
• 2012

In order to improve the adhesion between poly-monochloro-para-xylylene (Parylene-C) film and Aluminum thin film, the surface of Parylene-C film was irradiated by ${O_2}^+$ and $Ar^+$ ion beam generated by duoplamatron ion source. The ion dose of $Ar^+$ and ${O_2}^+$ was changed from $5{\times}10^{14}$ to $1{\times}10^{17}/cm^2$ and the ion beam energy was 1 kV. Contact angles of water on Parylene-C modified by $Ar^+$ and ${O_2}^+$ ion irradiation decreased from $78^{\circ}$ to around $17^{\circ}$, and $9^{\circ}$, respectively. X-ray photoelectron spectroscopy analysis shows that the hydrophilic groups were formed on the surface of Parylene-C by chemical reaction between the unstable chains induced by the ion irradiation and oxygen ions or residual oxygen gas. The hydrophilic groups were identified as C-O bond, C=O bond and (C=O)-O bond. The cross cut tape test which was applied to characterize the adhesion between Al thin film and Parylene-C film modified by ${O_2}^+$ ions irradiation shows that the adhesion strength was improved as increasing ion dose.

• Journal of the Korean Ceramic Society
• /
• v.46 no.4
• /
• pp.425-428
• /
• 2009

We performed a density functional theory study to investigate the interaction of DEMS (diethoxymethylsilane) with the H-terminated Si (001) surface. The optimum structure of DEMS was first calculated by a first principles study. The dissociation probability of the O-C bond of DEMS was higher than the other seven bonds based on the bond energy calculation. When the fragmented DEMS groups reacted with the H-terminated Si (001) surface, it was the most favorable among the eight reactions to form a bond between the Si atom on the surface and the O atom of a fragmented DEMS group (($C_2H_5O$)Si($CH_3$)(H)-O-) by forming a $C_2H_6$ as by-product.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.4
• /
• pp.953-958
• /
• 2010

A laser ablation-molecular beam/reflectron time-of-flight mass spectrometric technique was used to investigate the ion-molecule reactions that proceed within $Ti^+(CH_3COCH_3)_n$ heterocluster ions. The reactions of $Ti^+$ with $CH_3COCH_3$ clusters were found to be dominated exclusively by an oxidation reaction, which produced $TiO^+(CH_3COCH_3)_n$ clusters. These ions were attributed to the insertion of a $Ti^+$ ion into the C=O bond of the acetone molecule within the heteroclusters, followed by $C_3H_6$ elimination. The mass spectra also indicated the formation of minor sequences of heterocluster ions with the formulas $Ti^+(C_3H_4O)(CH_3COCH_3)_n$ and $TiO^+(OH)(CH_3COCH_3)_n$, which could be attributed to C-H bond insertion followed by $H_2$ elimination and to the sequential OH abstraction by the $TiO^+$ ion, respectively. Density functional theory calculations were carried out to model the structures and binding energies of both the association complexes and the relevant reaction products. The reaction pathways and energetics of the $TiO^+\;+\;CH_2CHCH_3$ product channel are presented.

• Korean Chemical Engineering Research
• /
• v.46 no.2
• /
• pp.389-396
• /
• 2008

The effect of thermal cycling on bond strength and residual stress at the interface between benzocyclobutene (BCB) and plasma enhanced chemical vapor deposited (PECVD) silicon dioxide ($SiO_2$) coated silicon wafers were evaluated by four point bending and wafer curvature techniques. Wafers were bonded using a pre-established baseline process. Thermal cycling was done between room temperature and a maximum peak temperature. In thermal cycling performed with 350 and $400^{\circ}C$ peak temperature, the bond strength increased substantially during the first thermal cycle. The increase in bond strength is attributed to the relaxation in residual stress by the condensation reaction of the PECVD $SiO_2$: this relaxation leads to increases in deformation energy due to residual stress and bond strength.