• Title/Summary/Keyword: IR spectra

검색결과 849건 처리시간 0.026초

Synthesis and Characterization of Cobalt(II)/(III), Nickel(II) and Copper(II) Complexes of New 14, 15 and 16-Membered Macrocyclic Ligands

  • El-Tabl, Abdou Saad
    • Bulletin of the Korean Chemical Society
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    • 제25권12호
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    • pp.1757-1763
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    • 2004
  • A new series of nickel(II), cobalt(II)/(III) and copper(II) complexes of 14, 15 and 16-membered of macrocyclic ligands have been prepared and characterized by elemental analyses, IR, UV-VIS and $^1H-NMR$ spectra, magnetic susceptibilities, conductivities, DTA and ESR measurements. Molar conductances in DMF solution indicate that, the complexes are nonelectrolytes except (9-12) complexes. The electronic spectra show that, all complexes are square planar or distorted octahedral geometry. The ESR spectra of solid complexes (4), (8) and (11) show square planar of axial type symmetry $(d_{x2-y2})$ with considerable covalent bond character. However, complex (12) shows a spectrum of octahedral geometry with $d_{z2}$ ground state. Complex (12) shows exploitation in reducing the amount of electron adducts formed in DNA during irradiation with low radiation products.

Structural Dynamics of Myoglobin Probed by Femtosecond Infrared Spectroscopy of the Amide Band

  • Kim, Seong-Heun;Jin, Geun-Young;Lim, Man-Ho
    • Bulletin of the Korean Chemical Society
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    • 제24권10호
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    • pp.1470-1474
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    • 2003
  • The dynamics of the tertiary conformation of myoglobin (Mb) after photolysis of carbon monoxide was investigated at 283 K solution by probing amide I and II bands using femtosecond IR absorption spectroscopy. Time-resolved spectra in the amide region evolve with 6-12 ps time scale without noticeable subpicosecond dynamics. The spectra measured at 100 ps delay after photolysis is similar to the difference FTIR spectrum at equilibrium. Time-resolved spectra of photoexcited Mb evolve modestly and their amplitudes are less than 8% of those of photolyzed MbCO, indicating that thermal contribution to the spectral evolution in the amide region is negligible. These observations suggest that the conformational relaxation ensuing photolysis of MbCO be complex and the final deoxy protein conformation have been substantially formed by 100 ps, probably with 6- 12 ps time constant.

A STUDY OF ISO SPECTRA FOR HERBIG Ae/Be STARS

  • Suh, Kyung-Won;Kim, Mi-Ryang;Baek, Ji-Hye
    • Journal of Astronomy and Space Sciences
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    • 제19권4호
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    • pp.255-262
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    • 2002
  • We present the infrared spectra of Herbig Ae/Be stars including the Infrared Space Ob-servatory (ISO) data. To investigate the overall properties of their circumstellar dust envelope and/or disk, we combine the IR spectra with photometric data ranging from the UV through the optical into the sub-mm region. We study the general characteristics of the spectral energy distributions using simple analysis. We plot the positions on the HR-diagram to compare with the theoretical pre-main-sequence evolution tracks.

The out-of-plane Band Contour of Dichloroborane Molecules

  • Lee, Kuk-Haeng;Kim, Ja-Hong;Sohn, Sung-Ho;Shim, Sang-Chul
    • Bulletin of the Korean Chemical Society
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    • 제8권3호
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    • pp.147-149
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    • 1987
  • The out-of-plane bending, vibrational-rotational FT-IR spectra of dichloroborane molecule were analyzed. The band centers are 785.992, 785.723, 647.217, and 646.997 $cm^{-1}$ and centrifugal distortion constants are $2.2{\times}10^{-6},\;5.5{\times}10^{-6},\;0.2{\times}10^{-6}$, and $0.7{\times}10^{-6}cm^{-1}$ for $H^{11}B^{35}Cl_2$, $H^{11}B^{35}Cl^{37}Cl$, $D^{11}B^{35}Cl_2$, and $D^{11}B^{35}Cl^{37}Cl$, respectively. The theoretical spectrum of $D^{11}B^{36}Cl_2$ was plotted to conform the molecular constants and the rotational constants for the first excited vibrational state of this molecule were A' = 1.165932, B' = 0.106166, and C' = 0.097229 $cm^{-1}$. The calculated spectra were in good agreement with the observed spectra.

과산화수소에 의한 모발의 화학적 손상에 관한 분광학적 평가 (Spectroscopic Evaluation on the Chemical Damage of Hair by Hydrogen Peroxide)

  • 하병조
    • 공업화학
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    • 제22권5호
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    • pp.579-581
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    • 2011
  • 과산화수소에 의한 모발의 화학적 손상을 SEM/EDS, CLSM, FT-IR을 통해 평가하였다. SEM/EDS상에서 과산화수소 처리된 모발은 미처리 모발에 비해 표면의 비늘구조 사이의 간격이 벌어졌고, 구성원소를 분석한 결과 황의 비율이 감소하였으며 산소의 비율은 상대적으로 증가하였다. CLSM 관찰 결과 미처리 모발은 강한 형광을 나타내었지만, 탈색모발은 낮은 형광을 보여주었다. 이는 미처리 모발의 경우 자동형광을 나타낼 수 있는 방향족 아미노산이 많이 존재하는데 비해, 탈색모발은 방향족 아미노산이 파괴되어 형광이 낮게 나온 것으로 볼 수 있다. 또한 FT-IR 분석결과 탈색의 증가에 따라 시스테인산(cysteic acid)이 증가되었으며, 이는 폴리펩타이드 사슬사이에 다리결합을 하고 있는 시스틴의 산화에 의한 것으로 볼 수 있다. 이러한 결과들은 산화적 손상이 S-S 결합을 파괴하고 모발 섬유의 인장력을 낮추어 주는 것을 의미한다.

바디나물 열매의 Coumarin 성분 연구(I) (A Study on Coumarins of Angelica decursiva)

  • 육창수
    • 생약학회지
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    • 제6권3호
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    • pp.149-150
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    • 1975
  • Silicagel colum chromatography of the ether extract of the fruits of Angelica decursiva $F_R$. et SAV. gave four crystalline products of coumarins and one steroid. The following furocoumarins and ${\beta}-sitosterol$ were identifed by UV, IR, NMR spectra and physicochemical tests: ${\beta}-sitosterol$, iso-imperatorin, imperatorin, bergapten, umbelliferone.

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