• Title/Summary/Keyword: CoE

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Stereoselective Electron-Transfer Reaction between Optical Active Cobalt(III) Complex and Racemic Cobalt(II) Complex (광학활성 코발트 (III) 착물과 라세미-코발트(II) 착물간의 입체선택적 전자전달반응)

  • Dong-Jin Lee;Maeng-Jun Jung;Myung-Ki Doh
    • Journal of the Korean Chemical Society
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    • v.35 no.5
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    • pp.500-505
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    • 1991
  • The stereoselectivity on the electron-transfer reaction between optical active ${\bigwedge}$-[CO(EDDS)]- and conformationally restricted complex $[Co({\pm}chxn)_3]^{2+}$ has been examined in aqueous solution. The products are four conformational isomers $(lel_3,\;lel_2ob,\;lelob_2,\;and\;ob_3)$ of ${\bigwedge}$-[Co(chxn)$_3]^{3+}$ with optical purities of 22% e.e, 25% e.e, 11% e.e, and 10% e.e, respectively. The reaction between ${\bigwedge}$-[CO(EDDS)]- and $[Co({\pm}chxn)_3]^{2+}$ in DMSO produced lel3-${\Delta}$ and lel2ob-${\Delta}$-[Co(chxn)$_3]^{3+}$ whose optical purities are 100% e.e, and 75% e.e, respectively.

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Stereoselective Electron Transfer and Ionic Association between Λ$-[Co(EDDS)]^-and [Co(en)_3]^{2+}$ (광학활성인 Λ$-[Co(EDDS)]^-$$[Co(en)_3]^{2+}$간의 입체선택적 전자전달 및 이온회합)

  • Lee, Dong Jin;O, Chang Eon;Do, Myeong Gi
    • Journal of the Korean Chemical Society
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    • v.34 no.2
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    • pp.159-164
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    • 1990
  • Absolute configuration of optically active [Co(EDDS)]- (EDDS = ethylenediaminedisuccinate) complex was determined as Λ-form by octant rule and spectroscopic data, and the stereoselective ionic association of Λ-[Co(EDDS)]- and racemic-$[Co(en)^3]_{3+}$ occurs preferrentially between Λ$-[Co(EDDS)]-$ and Δ$-[Co(en)3]3+$. The stereoselective electron-transfer reaction between Λ-[Co(EDDS)]- and racemic-$[Co(en)_3]^{2+}$ has produced 14% e.e (e.e = enantiomeric excess) of Δ$[Co(en)_3]^{3+}$ through the stereoselective ion pairing.

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Microsecond molecular dynamics simulations revealed the inhibitory potency of amiloride analogs against SARS-CoV-2 E viroporin

  • Jaber, Abdullah All;Chowdhury, Zeshan Mahmud;Bhattacharjee, Arittra;Mourin, Muntahi;Keya, Chaman Ara;Bhuyan, Zaied Ahmed
    • Genomics & Informatics
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    • v.19 no.4
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    • pp.48.1-48.10
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    • 2021
  • Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) encodes small envelope protein (E) that plays a major role in viral assembly, release, pathogenesis, and host inflammation. Previous studies demonstrated that pyrazine ring containing amiloride analogs inhibit this protein in different types of coronavirus including SARS-CoV-1 small envelope protein E (SARS-CoV-1 E). SARS-CoV-1 E has 93.42% sequence identity with SARS-CoV-2 E and shared a conserved domain NS3/small envelope protein (NS3_envE). Amiloride analog hexamethylene amiloride (HMA) can inhibit SARS-CoV-1 E. Therefore, we performed molecular docking and dynamics simulations to explore whether amiloride analogs are effective in inhibiting SARS-CoV-2 E. To do so, SARS-CoV-1 E and SARS-CoV-2 E proteins were taken as receptors while HMA and 3-amino-5-(azepan-1-yl)-N-(diaminomethylidene)-6-pyrimidin-5-ylpyrazine-2-carboxamide (3A5NP2C) were selected as ligands. Molecular docking simulation showed higher binding affinity scores of HMA and 3A5NP2C for SARS-CoV-2 E than SARS-CoV-1 E. Moreover, HMA and 3A5NP2C engaged more amino acids in SARS-CoV-2 E. Molecular dynamics simulation for 1 ㎲ (1,000 ns) revealed that these ligands could alter the native structure of the proteins and their flexibility. Our study suggests that suitable amiloride analogs might yield a prospective drug against coronavirus disease 2019.

Valence Band Photoemission Study of Co/Pd Multilayer (광전자분광법을 이용한 Co/Pd 다층박막의 전자구조연구)

  • Kang, J.-S.;Kim, S.K.;Jeong, J.I.;Hong, J.H.;Lee, Y.P.;Shin, H.J.;Olson, C.G.
    • Journal of the Korean Magnetics Society
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    • v.3 no.1
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    • pp.48-55
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    • 1993
  • We report the photoemission (PES) studies for the Co/Pd multilayter. The Co 3d PES spectrum of Co/Pd exhibits two interesting features, one near the Fermi energy, $E_{F}$, and another at ~2.5 eV below $E_{F}$. The Co 3d peak near $E_{F}$ of Co/Pd is much narrower than that of the bulk Co, consistent with the enhanced Co magnetic moment in Co/Pd compared to that in the bulk Co. The Co 3d feature at ~-2.5 eV resembles the Pd valence band structures, which suggests a substantial hybridization between the Co and Pd sublayers. The Co 3d PES spectrum of Co/Pd is compared with the existing band structures, obtained using the local spin density functional calculations. A reasonable agreement is found concerning the bandwidth of the occupied part of the Co 3d band, whereas a narrow Co 3d peak near $E_{F}$ seems not to be described by the band structure calculations.

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Studies on Electroanalytical Chemistry for the Oxygen Adducted Tetradentate Schiff base Cobalt(III) Complexes in Pyridine Solution (Pyridine 용액에서 산소 첨가된 네자리 Schiff base Cobalt(III) 착물들의 전기 분석화학적 연구)

  • Rim, Chae-Pyeong;Chae, Hee-Nam;Chjo, Ki-Hyung;Choi, Yong-Kook
    • Analytical Science and Technology
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    • v.8 no.1
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    • pp.55-62
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    • 1995
  • Tetradentate Schiff base cobalt(II) complexes such as $Co(II)_2-N$, N-bis(salicylidene)-m-phenylendiimine; [$Co(II)_2(SMPD)_2(H_2O)_4$] and $Co(II)_2-N$, N-bis(salicylidene)-p-phenylendiimine: [$Co(II)_2(SPPD)_2(H_2O)_4$], and oxygen adducted cobalt (III) complexes such as [$Co(III)_2O_2(SMPD)_2(Py)_2$] and [$Co(III)_2O_2(SPPD)_2(Py)_2$] in pyridine solutions were synthesized. It was identified that the oxygen adducted cobalt(III) complexes have hexacoordinated octahedral configuration with pyridine and oxygen from the measurement of elemental analysis, AA, IR spectra, and TGA. The redox processes were investigated for the oxygen adducted complexes in 0.1M TEAP-pyridine solution, using cyclic voltammetry on the glassy carbon electrode. The redox processes of oxygen adducted Co(III) complexes result in $$[Co(III)_2-O_2-CO(III)]\rightarrow^{e^-}[Co(III)-O_2-Co(II)]\rightarrow^{e^-}[Co(II)-O_2-Co(II)]\rightleftarrows^{e^-}[Co(II)+Co(II)+O_2{\cdot}^-]\rightleftarrows^{e^-}[Co(II)+Co(I)+O_2{\cdot}^-]\rightleftarrows^{e^-}[Co(I)+Co(I)+O_2{\cdot}^-]$$.

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Estimation and Feature of Greenhouse Gas Emission in Building Sector by National Energy Statistic (국가 에너지통계에 따른 건물부문 온실가스 배출량 추계 및 특성)

  • Jeong, Young-Sun;Kim, Tae-Hyoung
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.7
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    • pp.187-195
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    • 2019
  • In December 2015, The Paris Agreement was adopted to undertake ambitious efforts to combat climate change. Korean government announced its goal of reducing the country's greenhouse gas emissions by up to 37% below business as usual projections by 2030 in 2015. The purpose of this study was to set up the calculation methodology of GHG emission($CO_{2e}$) in building sector and to estimate the annual GHG emission in building sector based on national energy consumption statistic. The GHG emission from buildings is about 135.8 million ton $CO_{2e}$ as of 2015, taking up about 19.6% of Korea's entire emission and is about 144.7 million ton $CO_{2e}$ in 2017. The GHG emission of building sector is increasing at annual rate of 2.0% from 2001 to 2017. The GHG emission from electricity consumption in buildings is 91.8 million ton $CO_{2e}$ in 2017, is the highest $CO_2$ emission by energy source. The results show that the intensity of GHG emission of residential building sector is $40.6kg-CO_{2e}/m^2{\cdot}yr$ and that of commercial building sector is $68.4kg-CO_{2e}/m^2{\cdot}yr$.