• Bulletin of the Korean Chemical Society
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• 제21권1호
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• pp.49-55
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• 2000

A series of m-, and p-substituted phenyl 2-thiophenecarboxylates and benzoates was prepared by the reaction of the corresponding acyl chlorides and phenols. Their $^1H$ and $^{13}C$ NMR chemical shifts were analyzed using single substituent parameter (S SP) and dual substituent parameter (DSP) methods. The relative aromaticity index of thiophene was estimated to be 0.92 from the plot of the chemical shift of the carbonyl carbons of the thienoyl esters against chemical shift of the carbonyl carbons of the benzoyl esters.

• Journal of Pharmaceutical Investigation
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• 제23권3호
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• pp.155-163
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• 1993

Inclusion complexation of 1,7,21,27-tetraaza[7.1.7.1]paracyclophane (CPM 55) with 2,7-dihydroxynaphthalene (2,7-DHN) or 1,3-dihydroxynaphthalene (1,3-DHN) in pD 1.17 $DCl-D_2O$ solution was investigated by $^1H$ nuclear magnetic resonance spectroscopy (NMR) using 4,4'-dimethylaminodiphenylmethane (ACM 11) as an acyclic analog of CPM 55. In CPM 55-naphthalene derivative complex, alkyl protons located in the cavity of CPM 55 were shown to be subjected to anisotropic shielding and protons of naphthalene moiety shifted remarkably to upfield. However, in ACM 11-naphthalene derivative systems, chemical shifts for protons of both DHN compounds were not significant. The remarkable chemical shift changes suggested that the naphthalene moiety of 2,7-DHN or 1,3-DHN was included in the hydrophobic cavity of CPM 55 in aqueous solution. From the continuous variation plots of induced chemical shifts of 2,7-DHN, it was found that 2,7-DHN was included in the cavity of CPM 55 at 1:1 molar stoichiometry. Both computer simulation of a inclusion complex and strong upfield chemical shift changes of 2,7-DHN protons supported the conformation of pseudoaxial inclusion as the presumed geometry of the host-guest complex.

• 대한화학회지
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• 제36권3호
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• pp.345-350
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• 1992

Ln$(NO_3)_3$/DMF 상자성 용액의 양성자 선-나비와 화학적이동을 240 K부터 380 K 사이에서 측정하였다. 이들 데이터로부터 DMF 분자의 CHO기에 대한 배위구 교환속도와 열역학 교환파라미터를 추출하였다. 1/$T_2$ 와 ${\Dellta}{\omega}$ 데이터의 온도의존성을 자세하게 분석하고 고찰하여 결과를 정리하였다. 분석의 결과를 살펴보면 짝짓지 않은 전자 스핀이 몇몇 $Ln^{3+}$이온에서 첫 배위구를 넘어 퍼지면서 bulk 용매의 DMF 분자로 스칼라이완의 기여를 제공하는 것 같다.

• Archives of Pharmacal Research
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• 제9권4호
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• pp.229-232
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• 1986

Three inexpensive oxidation reagents, namely pyridinium chlorochromate, chromium trioxide-dipyridine and nicotinium dichromate were utilized for oxidation of carbohydrates in 78-92% yield. Hydration could be eliminated in the oxidation of pentopyranosides and hexopyranosides, while pentofuranosides had a tendency to be easily hydrated during the oxidation. In the carbon-13 n. m. r. study, the carbonyl function resulted from the oxidation affected on the chemical shifts of $\alpha$- and $\beta$-carbons of methyl 3. 4-O-isopropylidene-$\beta$-D-arabinopyranosid-2-ulose (8) and 1,2 : 4, 5-di-O-isopropylidene-$\beta$-D-erythro-2, 3-hexodiulo-2, 6-pyranose (10) to slightly down fields (0.7-2.6 p. p. m.) compared with the chemical shifts before oxidation. While the carbonyl groups of 1. 2-O-isopropylidene-5-O-ethyloxycarbonyl-$\alpha$-D-erythro-pentofuran-3-ulose (4) and methyl 3, 5-0-isopropylidene-$\alpha$-D-threo-pentofuranosid-2-ulose (6) pushed the $\alpha$-carbons to up fields (3, 2-18.3 p. p. m. However, the order of signals on the spectra before and after oxidation remained unaltered.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.517-520
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• 2004

Organosilicate films are promising porous low-dielectric materials, which can replace the silicon dioxide films. It was researched that organosilicate films have two different chemical shifts according to the increase of the flow rate ratio. There are the red shift due to the electron deficient substitution group, and the blue shift of the electron rich substitution group. Among these chemical shifts, the blue shift from $1000 cm^{-1}$ to $1250 cm^{-1}$ was related with the formation of pores. The methyl radicals of the electron-rich substitution group terminate easily the Si-O-Si cross-link, and the Si-O-C cage-link near $1057 cm^{-1}$ is originated from the cross-link breakdown due to much methyl radicals.

• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.807-815
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• 2001

Two-dimensional (2D) correlation method, which generates the synchronous and the asynchronous 2D spectrum by complex cross correlation of the Fourier transformed spectra, is an analysis method for the changes of the sample spectrum induced by vari ous perturbations. In the present work, the 2D electronic correlation spectra have been simulated for the cases where the sample spectrum composed of two gaussian bands changes linearly. When only the band amplitudes of the sample spectrum change, the synchronous spectrum shows strong peaks at the band centers of the sample spectrum, but the asynchronous spectrum does not make peaks. When the sample spectrum shifts without changing intensity and width, the synchronous spectrum shows peaks around the initial and final positions of the band maximum and the asynchronous spectrum shows long peaks spanning the shifting range. The band width change produces the complex 2D correlation spectra. When the sample spectrum shifts with band broadening, the width change by 50% of full width at half maximum (FWHM) does not give so large an effect on the correlation spectrum as the spectral shift by one half of FWHM of the sample spectrum.

• Bulletin of the Korean Chemical Society
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• 제16권11호
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• pp.1033-1037
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• 1995

PVC-based calcium-selective electrodes doped with ETH 129 usually suffer from a shift in the standard potential when they are in contact with protein-containing solutions (e.g. blood serum) after being calibrated with aqueous standards. The shift is due to the development of asymmetry potential in inherently symmetric PVC membranes through the contamination of outer membrane surface by proteins in the biological samples. Membranes prepared with polyurethane showed much reduced shifts in terms of standard potential. This study was performed with a flow-injection system following a protocol designed to observe minor shifts in baseline potential. Other electrochemical properties of the system, including selectivity and response slope, were similar to those obtained with regular PVC-based ones. PVC-based calcium selective membrane electrodes, doped with commonly used ETH 1001, were also tested to compare their electrochemical performances.

• 한국자기공명학회논문지
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• 제27권3호
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• pp.17-22
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• 2023

Bloom syndrome protein (BLM) is a pivotal RecQ helicase necessary for genetic stability through DNA repair processes. Our investigation focuses on the N-terminal region of BLM, which has been considered as an intrinsically disordered region (IDR). This IDR plays a critical role in DNA metabolism by interacting with other proteins. In this study, we performed triple resonance experiments of BLM_220-300 and presented the backbone chemical shifts. The secondary structure prediction based on chemical shifts of the backbone atoms shows the region is disordered. Our data could help further interaction studies between BLM_220-300 and its binding partners using NMR.

• 분석과학
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• 제7권2호
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• pp.213-224
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• 1994

선택적으로 중수소를 치환시킨 싸이클로옥타논의 여러 동위원소 이성질체들을 합성하였다. 고유동위원소 효과에 의해 영향을 받는 $^{13}C$ NMR 화학적 이동값들을 각 이성질체에 대해 저온에서 계통적으로 관찰하였다. 특히 싸이클로옥타논이 선호하는 안정한 형태 이성질체인 클 boat-chair 형과 연관시켜 이 효과들을 논의하였다.

• Bulletin of the Korean Chemical Society
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• 제29권11호
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• pp.2252-2258
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• 2008