• Korean Journal of Crystallography
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• v.11 no.2
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• pp.75-79
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• 2000

The complex [Cu(L)(H2O)2] (PDC)(1)(L=2,5,9,12-tetramethyl-1,4,8,11- tetraazacyclotetradecane;PDC=1,4-pyridinedicarboxylate) has been synthesized and characterized by X-ray crys-tallography. The compound 1 crystallizes in the triclinic space group P1, with a=7.553(1)Å, b=9.619(2)Å, c=10.692(2)Å, α=74.22(1)°, β=73.32(1)°, γ=78.70(1)°, V=710.1(2)Å3, Z=1,R1(wR2) for 2634 observed reflections of [I>2σ(I)] was 0.0854(0.2242). The compound 1 is interconnected to give a three-dimensional network through weak hydrogen-bonding interactions.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2897-2902
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• 2010

Seven fully optimized geometries of 3,6-dihydrazino-1,2,4,5-tetrazine (DHT) dimers have been obtained with density functional theory (DFT) method at the B3LYP/$6-311++G^{**}$ level. The intermolecular interaction energy was calculated with zero point energy (ZPE) correction and basis set superposition error (BSSE) correction. The greatest corrected intermolecular interaction energy of the dimers is $-23.69\;kJ{\cdot}mol^{-1}$. Natural bond orbital (NBO) analysis is performed to reveal the origin of the interaction. Based on the vibrational analysis, the changes of thermodynamic properties from the monomers to dimer with the temperature ranging from 200.0 K to 800.0 K have been obtained using the statistical thermodynamic method. It was found that the hydrogen bonds dominantly contribute to the dimers, while the binding energies are not only determined by hydrogen bonding. The dimerization process can not occur spontaneously at given temperatures.

• Elastomers and Composites
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• v.45 no.3
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• pp.165-169
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• 2010

Recently supramolecular network thermo-reversible crosslinking elastomer having flexibility, various functionality, and advantages of thermoplastic elastomer (TPE) such as recycle and easy processbility is introduced. Although thermo-reversible bonds such as hydrogen bond and ionic cluster is recognized as a common technology since 1990, control technology of bonding and dissociation of crosslink in supramolecular network is a recent technology. In this review, characteristics of thermo-reversible crosslinking elastomer having rheological properties of TPE and reinforcing behaviors of thermoset elastomer are summarized.

• Korean Journal of Crystallography
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• v.13 no.1
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• pp.12-16
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• 2002

The complex [Ni(L)](BDC)·4H₂O (1) (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[16,4,O/sup 1.18/,O/sup 7.12/] docosane; BDC = 1,3-benzenedicarboxylate) has been synthesized and characterized by X-ray crystallography. Compound 1 crystallizes in the orthorhombic space group Pcnb, with a = 8.764(2) , b = 17.687(2) , c = 19.475(1) , V = 3018.7(8) ³, Z = 4, R₁, (wR₂) for 2148 observed reflections of [1>2σ(I) was 0.0822 (0.2236). Compound 1 is interconnected to give a three-dimensional network through weak hydrogen-bonding interactions.

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.209-215
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• 1988

The three-dimensional structures of piroxicam crystallized from two different solvents, toluene and toluene/hexane mixture respectively, are proved identical: $C_{15}H_{13}N_3O_4S,\;M\;=\;331.35$, monoclinic, a = 7.128(1), b = 15.146(2), c = 13.956(2) ${\AA},\;{\beta}=\;97.33(1)^{\circ},\;V\;=\;1494.37{\AA}^{3},\;Dx\;=\;1.472\;g/cm^{3},\;Z\;=\;4,\;space\;group\;P2_{1}/c,\;Mo\;K{\alpha}(\lambda=\;0.71073\;{\AA})$, F(000) = 688, T = 295 K, R = 0.0611 for 1993 unique observed reflections. The thiazine ring exhibits a half chair conformation. An amide group is involved in an intramolecular hydrogen bond to the hydroxy group, O(17)-H(17)${\cdots}O(15){\AA}$. The molecule is planar within 2 ${\AA}$ with the interplanar angle $127.9(4)^{\circ}$ between pyridine and benzene rings. A molecular chain parallel to [011] is formed by two intermolecular hydrogen bonds N(16)-H(6)${\cdots}O(11)$ and C(6)-H(6)${\cdots}O(11)$, and the molecular chains are held together by van der Waals forces.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.115-122
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• 2008

The hydrosilylation is an addition reaction of Si-H bond to unsaturated double bonds, which provides a convenient mechanism to synthesize poly(dimethylsiloxane-co-methylsiloxane)copolymer having siloxy units in polymer backbone. In this study, Poly(dimethylsiloxane-co-methylsiloxane) copolymer was synthesized through the polymerization reaction of cyclopentasiloxane with poly(methyl-hydrogen) siloxane. Silicone-hydrogen functional group of the poly(dimethylsiloxane-co-methylsiloxane) copolymer was substituted to the alkyl groups by hydrosilylation. And their structure was analyzed with FT-IR, H-NMR and GPC instruments, respectively. Surface tension of the synthetic compounds is increased from 22dyne/cm to 25dyne/cm according to increase additional EO moles. The cmc which was evaluated by surface tension was ranged $10^{-5}$ to $10^{-4}mol/L$ and it was decreased according to increase of dimethyl siloxyl content. HLB number of these surfactants was evaluated 9.5 to 11.5 range. These silicone surfactants is applied to self-emulsifier defoamer and personal care products as surface tension depressant, emulsifier, foam control agent.

• Bulletin of the Korean Chemical Society
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• v.16 no.10
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• pp.912-915
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• 1995

Ornidazole, C7H10ClN3O3, crystallizes in the triclinic, space group P1^, with a=13.605(2), b=14.054(1), c=8.913(5) Å, α=71.59(2), β=78.73(2), γ=64.86(1)°, μ=3.26 cm-1, Dc=1.499 g/cm3, Dm=1.497g/cm3, F(000)=684, and z=6. Intensities for 2693 unique reflections were measured on a CAD4 diffractometer with graphite-monochromated Mo-Kα radiation. The structure was solved by direct method and refined by block-diagonal least squares to a final R of 0.081 (Rw=0.047) for 1952 reflections with Fo>3σ (Fo). The asymmetric unit contains three independent molecules of the title compound. The bond lengths and bond angles are comparable with the values found in the other nitro-substituted compounds. The nitro groups are rotated (6.9°, 6.6°, 2.6° for the three independent molecule, respectively) about the C-N axes from the imidazole planes. The crystal structures are linked by two intermolecular hydrogen bonds of O-H---N type and one intermolecular hydrogen bond of O-H---O type.

• YAKHAK HOEJI
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• v.21 no.3
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• pp.146-158
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• 1977

N$_{1}$-cyclohexyl-$N_{2}$-(o-chlorobenzal) imino thiourea, $C_{14}$H$_{18}$N$_{3}$SCI, crystallizes in $C_{2}$/c, with a=19.68, b=7.74, c=20.42$\AA$, ${\beta}$=$92.$8^{\circ}$ and eight formula units in the unit cell. The structure was solved by the study of Patterson sections, calculated from three-dimensional film data, and was refined by block-diagonal least-squares methods to R=0.16 based on 1288 independent intensity data. The rest atoms of N$_{1}$-cyclohexyl-$_{2}$-(o-chlorobenzal) imino thiourea molecule excluding cyclohexan ring and chlorine atoms approximately lie on a plane. A pair of molecules related by the symmetry centers are connected directly with the N-H.......S hydrogen bonds. Apart from the hydrogen bonding system the structure is held together by the van der Waals forces.

• Archives of Pharmacal Research
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• v.16 no.2
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• pp.134-139
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• 1993

The molecular structure of acemetacin, 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid carboxymethyl ester, was determined by single cystal X-ray diffraction analysis. The compound was recrystallized from a mixture of acetone and water in triclinic, space group P1, with a=7.796(1), b=10.245(2), c=13.542(3)$\AA,\;\alpha=97.35(1),\;\beta=96.34(1),\;\gamma=107.06(1)^\circ$, and Z=2. The calculated density is 1.422; the observed value is $1.42\;g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0,037 for 2960 independent reflections. There are water molecules, which are thought to be co-crystallized during the evaporation procedure, with the ratio of one water per compound molecule in the crystal. The conformation of the compound is found to be very similar to that of indomethacin. The molecules are stabilized by three O-H.....O type intermolecular hydrogen bonds between the oxygen of water molecule and those of the compound.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.6-13
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• 2022

The electrostatic phenomenon seriously issued in extreme ultraviolet semiconductor cleaning was studied in junction with molecular dynamic aspect. It was understood that two lone pairs of electrons in water molecule were subtly different each other in molecular orbital symmetry, existed as two states of large energy difference, and became basis for water clustering through hydron bonds. It was deduced that when hydrogen bond formed by lone pair of higher energy state was broken, two types of [H₂O]⁺ and [H₂O]^- ions would be instantaneously generated, or that lone pair of higher energy state experiencing reactions such as friction with Teflon surface could cause electrostatic generation. It was specifically observed that, in case of electrolyzed cathode water, negative electrostatic charges by electrons were overlapped with negative oxidation reduction potentials without mutual reaction. Therefore, it seemed that negative electrostatic development could be minimized in cathode water by mutual repulsion of electrons and [OH]^- ions, which would be providing excellences on extreme ultraviolet cleaning and electrostatic control as well.