• Journal of the Korean Magnetic Resonance Society
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• v.25 no.1
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• pp.1-7
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• 2021

Employing of 13C stable-isotopes in NMR metabolomics can give unique splitting patterns and coupling constants information originated from 13C-13C coupling interaction that provide an important structural information regarding the cellular metabolic process. But it has been known that an undesirable signal distortion in 2D heteronuclear correlation study, due to 13C-13C interaction, hampers an analysis of the coupling information. Recently, we proposed J-scaled distortion-free heteronuclear single-quantum coherence (HSQC) sequence which provides a distortion-free 13C-13C coupling information with a selective resolution enhancement of JCC splitting. In this paper, we dicuss theoretical aspect and practical feature of J-scaled HSQC pulse sequence. The conceptual explanation of orgin of the signal distortion by 13C-13C coupling interaction and design of J-scaled HSQC through exemplified results are provided in brief.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1566-1571
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• 2007

Oligodeoxyribonucleotide bearing the di-acetylenic linkage has been prepared. Staring from 5-Iodo-2'-deoxyuridine(1), a four-step sequence, consisting of the Pd(0)-catalyzed Heck-type C-C coupling with acetylenic group, protection of 5'-hydroxy group, generation of acetylenic hydrogen, and Glaser oxidative coupling reaction leads to the dimeric oligodeoxyribonucleotide(5).

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.422-426
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• 1999

The Grignard reactions of bis(chloromethyl)dimethylsilane (1) with trimethylchlorosilane (2) in THF give both the intermolecular C-Si coupling and intramolecular C-C coupling products. At beginning stage, 1 reacts with Mg to give the mono-Grignard reagent ClCH2Me2SiCH2MgCl (1) which undergoes the C-Si coupling reaction to give MC2Si(CH2SiMe3)2 3, or C-C coupling to a mixture of formula Me3SiCH2(SiMe2CH2CH2)nR1 (n = 1, 2, 3, ..; 4a, R1I = H: 4b, R1 = SiMe3). In the reaction, two reaction pathways are involved: a) Ⅰ reacts with 2 to give Me3SiCH2SiMe2CH2Cl 6 which further reacts with Mg to afford a Me2SiCH2Mel-SiCH2MgCl (Ⅱ) or b) I cyclizes intramolecularly to a silacyclopropane intermediate A, which undergoes a ring-opening polymerization by the nucleophilic attack of the intermediates I or Ⅱ, followed by the termination reaction with H2O and 2, to give 4a and 4b, respectively. As the mole ratio of 2/1 increased from 2 to 16 folds, the formation of product 3 increased from 16% to 47% while the formation of polymeric products 4 was reduced from 60% to 40%. The intermolecular C-Si coupling reaction of the pathway a becomes more favorable than the intramolecular C-C coupling reaction of the pathways b at the higher mole ratio of 2/1.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.107-113
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• 2004

Several transition metal complexes, [$M(L)X_2$](M=Pd(II), Ni(II); X=CI, Br) are prepared with aminophosphine ligands such as 1,2-bis{(diphenylphosphino)amino}ethane{$Ph_2PNHCH_2CH_2NHPPh_2$}($L_1$), 1,2-bis{(diphenylphosphino)amino}propane{$Ph_2PNHCH(CH_3)CH_2NHPPh_2$}($L_2$), trans-1,2-bis{(diphenylphosphino)amino}cyclohexane{$Ph_2PNHC_6H_{10}NHPPh_2$}($L_3$) and 1,2-bis{(diphenylphosphino)amino}benzene{$Ph_2PNHC_6H_4NHPPh_2$}($L_4$). The properties of these complexes are characterized by optical spectroscopic methods including UV/vis spectroscopy, CD, IR, $^1H$- and $^{31}P-NMR$ together with conductometer and elemental analysis. All complexes are stable under atmospheric environment. Catalytic reactivity for C-C coupling between [$M(L)X_2$] and Grignard reagents(RMgX; R=phenyl, propyl, buthyl) by thermolysis were investigated utilizing GC/mass, $^1H$- and $^{13}C-NMR$. When mol scale is 1:20 at [$Pd(L)Cl_2$] and Grignard reagents, the high catalytic activity for C-C coupling is apparent. The [$M(L)X_2$](X=Cl, Br) complexes which have strong bond at M-P exhibit high yields for C-C coupling reactions. When the central metal ion is Pd(II), the high catalytic activity for C-C coupling is apparent. The complex coordinated with Br shows higher catalytic activity for C-C coupling reactions compared to Cl.

• YAKHAK HOEJI
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• v.37 no.6
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• pp.615-620
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• 1993

The cross-coupling reaction of organo tin reagents with a variety of organic halides, catalyzed by palladium, provides a novel method for generating a carbon-carbon bond. We used this method for the antibacterial agents, and synthesis of new quinolone derivatives which have carbon-carbon bond at C-7 position of general quinolone moieties. Aryl tin, quinolone moieties, and palladium catalyst were refluxed in DMF to afford new quinolone derivatives. This palladium catalyzed coupling reactions have capacity for further synthetic elaboration.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.181-190
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• 2019

In this study, four reinforced concrete coupling beams were subjected to cyclic lateral loading test to evaluate the structural performance of coupling beam according to volume fraction of steel fiber. For this purpose, the volume fraction of steel fiber(0%, 1%, 2%) and transverse reinforcement spacing were determined as the main parameter. According to the test results, the maximum strength of D-40C-s100-0 was 1.15, 1.13, 1.05 times higher than D-40C-s300-0, D-40C-s300-1, D-40C-s300-2, respectively. The maximum strength of coupling beams with mitigated rebar details increases as the volume fraction of steel fiber increases. Although steel fiber 2% reinforced specimen(D-40C-s300-2) did not satisfy the amount of transverse reinforcement required for seismic design of coupling beam, the overall performance including to maximum strength, ductility and energy dissipation capacity was similar to the control specimen(D-40C-s100-0). As a result, the use of steel fiber with 2% reinforcement can partially replace the transverse reinforcement in diagonally reinforced concrete coupling beam.

• Journal of Magnetics
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• v.7 no.1
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• pp.14-17
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• 2002

Magnetic multilayers of a ferromagnetic (FM)/insulator (I)/ferromagnetic (FM) structure have been studied to investigate magnetic exchange coupling between two FM layers. As the Mumetal $(Ni_{77}Fe_{14}Mo_{5}Cu_4$ wt%) growth temperature increases, the grain size and the surface roughness increase simultaneously. The smallest coupling field is obtained at $40^\circ{C}$ where the grain size is larger than that of the $20^\circ{C}$ sample. The exchange coupling field increases again at temperatures higher than $40^\circ{C}$ due to increase in the surface roughness of the Mumetal.

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.452-457
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• 1996

The effects caused by the ionization on the electronic structure and geometry on C60 are studied by the modified Su-Schriffer-Heeger (SSH) model Hamiltonian. After the ionization of C60, the bond structure of the singly charged C60 cation is deformed from Ih symmetry of the neutral C60 to D5d, C1, and C2, which is dependent upon the change of the electron-phonon coupling strength. The electronic structure of the C60+ cation ground state undergoes Jahn-Teller distortion in the weak electron-phonon coupling region, while self-localized states occur in the intermediate electron-phonon region, but delocalized electronic states appear again in the strong electron-phonon region. In the realistic strength of the electron-phonon coupling in C60, the bond structure of C60+ shows the layer structure of the bond distortion and a polaron-like state is formed.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1031-1037
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• 2004

The interaction of chemoattractant receptors and $G{\alpha}_{16}$ was studied to provide the molecular basis to elucidate the interaction of chemoattractant receptors with $G{\alpha}_{16}$ subunit, thereby possibly contributing to finding novel targets for designing new type of G protein antagonists with anti-inflammatory effects. Experiments were performed to characterize the $G{\alpha}_{16}$ subunit domains responsible for efficient coupling to chemoattractant receptors. Thus, a series of chimeric $G{\alpha}_{11}G{\alpha}_{16}$ and $G{\alpha}_{16}G{\alpha}_{11}$ cDNA constructs were expressed, and the ability of chimeric proteins to mediate C5a, IL-8, and fMLP-induced release of inositol phosphate in transfected Cos-7 cells was tested. The results showed that short stretches of residues 154 to residue 167 and from residue 174 to residue 195 of $G{\alpha}_{16}$ contribute to efficient coupling to the C5a receptor. On the other hand, a stretch of amino acid residues 220-240 of $G{\alpha}_{16}$ that is necessary for interacting with C5a receptor did not play any role in the interaction with IL-8 receptor. However, a stretch from residue 155 to residue 195 of $G{\alpha}_{16}$ was found to be crucial for efficient coupling to IL-8 receptor in concert with C-terminal 30 amino acid residues of this ${\alpha}$ subunit. Coupling profiles of a variety of chimeras, composed of $G{\alpha}_{11}G{\alpha}_{16}$ to fMLP receptor indicate that the C-terminal 30 amino acids are most critical for the coupling of $G{\alpha}_{16}$ to fMLP receptor. Taken together, $G{\alpha}_{16}$ subunit recruits multiple and distinctive coupling regions, depending on the type of receptors, to interact.

• Electrical & Electronic Materials
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• v.9 no.6
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• pp.584-592
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• 1996

Coupling optical modulator which on the $LiTaO_3$ substrate is fabricated by using proton exchange method and self-aligned method. Proton exchange of proton diffusion method was applied to pattern a waveguide on $LiTaO_3$ substrate. The annealing at >$400^{\circ}C$ was carded out to control waveguide width and depth. The depths of the two annealed optical waveguides, which were measured by using .alpha.-step, were 1.435 K.angs. and 1.380 K.angs. Using .alpha.-step facility, we examined that the width of waveguides is increased from 5.mu.m to 6.45 .mu.m and 6.3.mu.m due to the annealing effects. The process of proton exchange was done at 150.deg. C for 120 min, >$200^{\circ}C$ for 60 min and annealing process was done at >$400^{\circ}C$ for 90 min, >$400^{\circ}C$ for 60 min. The high speed coupling optical modulator has very good figures of merits; the measured high frequency power were achieved.