• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.977-982
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• 2004

The reaction of $cis-[Cr([14]-decane)(OH_2)_2]^+$ ([14]-decane = rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-teraazacyclotetradecane) with auxiliary ligands {$L_a$ = benzoate(bz) or chlorobenzoate(cbz)} leads to a new compound $[Cr([14]-decane)(bz)_2]ClO_4$ or $[Cr([14]-decane)(cbz)_2]ClO_4$. These complexes have been characterized by a combination of elemental analysis, conductivity, IR and Vis spectroscopy, mass spectrometry, and X-ray crystallography. The crystal structure of $[Cr([14]-decane)(cbz)_2]^+$ was determined. The complex shows a distorted octahedral coordination environment with the macrocycle adopting a folded cis-V conformation. The angle $N_{axial}-Cr-N_{axial}$ deviates by $14.5^{\circ}$ from the ideal value of $180^{\circ}$for a perfect octahedron. The bond angle cis-O-Cr-O between the Cr(III) ion and the two carboxylate oxygen atoms of the monodentate p-chlorobenzoate ligands is close to 90$^{\circ}$. The FAB mass spectra of the $cis-[Cr([14]-decane)(La)_2]ClO_4$ display peaks due to the molecular ions $[Cr([14]-decane)(bz)_2-H]^\;,\;[Cr([14]-decane)(cbz)_2-2H]^$ at m/z 578, 646, respectively.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.253-261
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• 2002

Vibrational properties of ferrocyanide complex ion, $[Fe(CN)_6]^{4-}$ , have been studied based on the force constants obtained from the density functional calculations at B3LYP/$6-31G^{\ast\ast}$ level by means of the normal mode analysis using new bond angle and linear angle internal coordinates recently developed. Vibrations of ferrocyanide were manipulated by twenty-three symmetry force constants. The angled bending deformations of C-Fe-C, the linear bending deformations of Fe-C${\equiv}$N and the stretching vibrations of Fe-C have been quantitatively assigned to the calculated frequencies. The force constants in the internal coordinates employed in the modified Urey-Bradley type potential were evaluated on the density functional force field applied, and better interaction force constants in the internal coordinates have been proposed. The valence force constants in the general quadratic valence force field were also given. The stretch-stretch interaction and stretch-bending interaction constants are not sensitive to the geometrical displacement in the valence force field.

• Advances in aircraft and spacecraft science
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• v.1 no.1
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• pp.1-14
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• 2014

Physico-chemical changes of the plasma modified titanium alloy [Ti-6Al-4V] surface were studied with respect to their crystallographic changes by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM).The plasma-treatment of surface was carried out to enhance adhesion of high performance nano reinforced epoxy adhesive, a phenomenon that was manifested in subsequent experimental results. The enhancement of adhesion as a consequence of improved spreading and wetting on metal surface was studied by contact angle (sessile drop method) and surface energy determination, which shows a distinct increase in polar component of surface energy. The synergism in bond strength was established by analyzing the lap-shear strength of titanium laminate. The extent of enhancement in thermal stability of the dispersed nanosilica particles reinforced epoxy adhesive was studied by Thermo Gravimetric Analysis (TGA), which shows an increase in onset of degradation and high amount of residuals at the high temperature range under study. The fractured surfaces of the joint were examined by Scanning electron microscope (SEM).

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3805-3810
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• 2013

The surface modification of silica particles (SPs) was systemically conducted by the treatment of 0.1-10 wt % phenylsilanetriol (PST) on the basis of SPs used through two step processes: 1) the PST coating of SPs via evaporation under reduced pressure and 2) their thermal condensation leading to Si-O-Si bond formation via heating at $130^{\circ}C$. The evaluation of the modified SPs was conducted by the simple floating test on water and the measurement of the contact angle (CA) of water droplet on the 2-dimensional layer of modified SPs on slide glass. When PST was used about 2 wt % or above on the basis of SPs (about average size: 50 nm) used, the modified SPs were fully floated on the water and all dispersed into upper organic solvent layer after a shaking with the mixture of the water and benzene, indicating that the modified SPs have hydrophobic properties. The modified SPs were characterized by $^{29}Si$ MAS NMR and physicochemical properties including SEM, TEM, BET, adsorption/desorption isotherms, etc. were measured and compared each other in details. This research demonstrates that the organosilanetriol is a good modifier applicable for the surface modification of inorganic oxide particles using a low amount of modifier on the basis of oxide particles used.

• Journal of the Korean Ceramic Society
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• v.43 no.1 s.284
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• pp.38-41
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• 2006

Surface of PC (Polycarbonate) and PES (Polyethersulphone) treated by plasma modification with rf power from 50 W to 200 W substrates in Ar (3 sccm), $O_2$ (12 sccm) atmosphere. From the results of modified substrates in XPS (X-ray Photoelectron Spectroscopy), the ratio of oxide containing bond increased with rf power. As the rf power was 200 W, the contact angle was the lowest value of 14.09 degree. And the datum from AFM (Atomic Force Microscopy), rms roughness value of PES and PC substrates increased with rf power. We could deposit $Ta_2O_5$ with good adhesion on plasma treated PES and PC substrates using by in-situ rf magnetron sputter.

• Archives of Pharmacal Research
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• v.3 no.1
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• pp.37-49
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• 1980

Chlorpropamide, $C_{10}H_{13}N_{2}O_{3}SCI$, forms orthofombic crystals of space group $P_{2}_{ 1}2_{1}2_{1}$ with a 9.066 $\pm$ 0.004, b = 5.218 $\pm$ 0.003, c = 26, 604 $\pm$, 0.008 $\AA$, and four molecules per cell. Three dimensional photographic data were collected with Mo-K$\alpha$ radiation. The structure was determined using Patterson, Fourier and Difference syntheses methods and refined by the block-diagonal least-squares methods with anisotropic thermal parameters for all nonhydrogen atoms and isotropic thermal parameters for all hydrogen atomes. The final R value was 0.10 for the 1823 observed independent reflections. The dihedral angle between the planes through the benzene ring and the urea goup is 99$^{\circ}$. The conformational angle formed by the projection of the S-C(1) with that of N(1)-C(7) when the projection is taken along the S-N(1) bond is 76$^{\circ}$. The molecule appears to form with neighbouring molecules two hydrogen bonds, N(1)..H...O(3) and N(2)-H...0(2) of lengths 2.774 and 2.954$\AA$ respectively related by screw diads parallel to the a axis. Adjacent molecules parallel to b and c axis are bound together by van der Wasls forces.

• Bulletin of the Korean Chemical Society
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• v.15 no.7
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• pp.553-559
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• 1994

Dynamics of $CH_2CI$ group in ${\alpha},2,6$-trichlorotoluene dissolved in $CDCl_3$ was studied by observing various relaxation modes for $^{13}C$ under proton undecoupled condition. Partially relaxed $^{13}C$ spectra were obtained at $34^{\circ}C$ as a function of evolution time after applying various designed pulse sequences to this $AX_2$ spin system. It was found that nonlinear regression analysis of the relaxation data for these magnetization modes could provide the information about dipolar and spin-rotational auto-correlation and cross-correlation spectral densities for fluctuation of the $^{13}C-^1H$ internuclear vector in $CH_2Cl$ group. The results show that the effect of cross-correlation is comparable in magnitude to that of auto-correlation and the relaxation in this spin system is dominated by dipolar mechanism rather than spin-rotational one. From the resulting spectral density data we could calculate the bond angle ${\angle}HCH\;(105.1$^{\circ}$) and elements of the rotational diffusion tensor for $CH_2Cl$ group.

• Textile Coloration and Finishing
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• v.5 no.4
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• pp.29-41
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• 1993

In order to surface Hydrophobilization of Poly(ethylene terephthalate) (PET) fiber samples were treated in the atmosphere of CF$_{4}$ or $C_{2}$F$_{6}$glow discharge. The sample used in this study was PET film which is 75$\mu$m thick made by Teijin, O-Type(Japan). The cleaned samples were placed in plasma reactor made of pyrex glass cylinder, and plasma processing was carried out by glow discharge of CF$_{4}$ or $C_{2}$F$_{6}$ gas, being continuously fed by gas flow and continuously pumped out by a vacuum system. Electric power source for generate plasma state was sustained alternating current(60Hz) and voltage was sustained 600 volt. The duration of plasma treatment varied from 15 to 120 seconds except special case, the monomer gase pressure varied from 0.02 to 0.3 Torr and power range was 10 to 90 watts. The hydrophobic features of changed PET surface were evaluated by contact angle measurement and surface chemical characteristics were analyzed by ESCA. Results can be summerized as follows. 1. The most favorable setting position of substrate was the center area between the two electrodes. 2. $C_{2}$F$_{6}$ discharge current was lower than that of CF$_{4}$ when same voltage was sustained. Treated efficiency between CF$_{4}$ and $C_{2}$F$_{6}$ did not revealed significant differences under same electric power(wattage). 3. When monomer pressure is very low below 0.02 torr, as though substrate is exposed to CF$_{4}$ or $C_{2}$F$_{6}$ plasma, it tend to be hydrophilic through a little of fluorine bond and a great deal of oxidizing reaction. 4. There brought good hydrophobilization when monomer pressure was more 0.1 torr and duration of glow discharge treatment was over 45 seconds. When monomer pressure was too high, discharge current became low. Although prolong the duration, there was no more high hydrophobilization. 5. According to ESCA analysis, there were a little CF bond and a prevailing CF$_{2}$ bond in CF$_{4}$-treated substrate. There were CF$_{3}$, a little CF and a prevailing CF$_{2}$ bond in $C_{2}$F$_{6}$-treated substrate.d substrate.

• Journal of the Korean Chemical Society
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• v.25 no.6
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• pp.343-350
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• 1981

The crystal and molecular structure of P-aminobenzaldehyde cyclohexylthiosemicarbazone, C14H20N4S, has been determined from 2712 integrated intensities measured on a computer controlled four circle diffractometer with monochromated $CuK_{\alpha}$, X-ray radiation. The crystals are monoclinic, space group C2/c with eight molecules in a unit cell of dimensions, a = 12.488(2), b = 12.276(4), c = 19.997(6)${\AA}$ and ${\beta}=103.55(3)^{\circ}$. The structure was solved by Patterson and Fourier method and refined by a full-matrix least squares method to a final R value of 0.058 for all reflections. The C(8)-S bond is trans to N(2)-N(3) and C(8)-N(1) is cis to N(2)-N(3) bond. The cyclohexane ring has chair conformation and makes an angle of $40.7^{\circ}$ with the benzene ring. The molecules are linked by N(2)H…S hydrogen bonds into dimer-like units which are held together by $N-H{\ldots}N$ hydrogen bonds. Sulfur accepts second rather weak hydrogen bond from N(4). An intramolecular hydrogen bond exists between N(1) and N(3) atoms.

• Journal of the Korean Wood Science and Technology
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• v.28 no.1
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• pp.36-41
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• 2000

This study was carried out to introduce functional groups onto wood by reacting with 2-methacryloyloxyethyl isocyanate(MOI). The effects of the catalyst and the reaction conditions(temperature and time) on the treatment were investigated. The evidence of bonding between wood and MOI were examined by infrared(IR) spectroscopy. The change in surface characteristics of MOI treated wood was examined by water contact angle measurement and X-ray photoelectron spectroscopy(XPS). Wood reacted quickly with MOI in the presence of di-n-butiltin dilaurate catalyst. Especially, the increase in weight percent gain(WPG) with increasing in reaction time was remarkable at the reaction temperature of over $50^{\circ}C$. The IR spectrum of wood reacted with MOI showed a strong urethane absorption(1715 $cm^{-1}$) but no isocyanate(2235 $cm^{-1}$) absorption. It also showed a sharp olefinic C=C double bond absorption at 1635 $cm^{-1}$. This means that an introduced methacrylate group becomes the starting point of further graft copolymerization with another vinyl monomers. The wood modified with MOI showed a gradual increase in contact angle with increasing in WPG, which means that the hydrophilic wood surface become quite hydrophobic. Also, it was cleared that most parts of the wood surface were modified with MOI by XPS analysis.