Results 251 to 260 of about 186,089 (306)

Theoretical IR, Raman and NMR spectra of 1,2- and 1,3-dimethylenecyclobutane

Vibrational Spectroscopy, 2001
Abstract Equilibrium geometries, rotational constants, harmonic vibrational frequencies, infrared intensities, Raman activities, and 1 H and 13 C NMR spectra were calculated for 1,2-dimethylenecyclobutane and its less stable isomer 1,3-dimethylenecyclobutane by using MP2, DFT (B3PW91), and RHF theoretical methods involving the 6-311++G ∗∗ basis ...
Joanna E Rode, Jan Cz Dobrowolski, Michał H Jamróz, Marek A Borowiak   +3 more
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Low-temperature NMR and IR Spectra of Photomerocyanine Form of Spirophenanthrooxazine

Chemistry Letters, 2003
Abstract Low-temperature 13C NMR and IR spectra of the metastable photomerocyanine (PMC) of spirophenanthrooxazine (SPO) show that PMC is in quinoidal structure. Especially, 13C NMR study directly evidences the formation of two quinoidal PMCs in CD2Cl2 upon UV irradiation. The quantum chemical study of SPO shows that among open forms TTC
Duck-Hyung Lee, Myunghee Lee, Chinkap Chung, Weon-Hee Lee, In-Ja Lee   +4 more
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The13C NMR, UV and IR spectra of 2-fluoropyridine methyl derivatives

Chemistry of Heterocyclic Compounds, 1999
13C NMR, UV, and IR spectra of methyl derivatives of 2-fluoropyridine have been recorded. The influence of the substituents on the spectral characteristics of the compounds has been discussed. The electronic spectra have been calculated by a modified INDO method. Transition energies, intensities, and assignments are compared with UV spectra.
A. Puszko, H. Ciurla
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Spectroscopic studies on soil organic fractions i. ir and nmr spectra

Soil Biology and Biochemistry, 1977
Abstract A study has been made using i.r. and n.m.r. spectroscopic techniques to investigate ten different organic fractions extracted in a series of mild organic solvents from a brown soil from Sardinia. The experimental results gave useful information about the nature of the extracted samples, which differ considerably from one another. Some of the
O. Sciacovelli, N. Senesi, V. Solinas, C. Testini   +3 more
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Isolation and Identification of 9-cis Astaxanthin by HPLC, FT-IR, and NMR Spectra

Journal of Applied Spectroscopy, 2021
This study aims to perform a detailed qualitative analysis of astaxanthin isomers. A rapid, open column chromatography method was developed to separate astaxanthin geometrical isomers in gram-scale levels. Chromatographic separation was performed using two silica gel columns with dichloromethane/n-hexane/diethyl ether (2:1:1, v/v/v) as elution system ...
Y. Wang, Y. Wu, T. Wang, D. Qiua
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E-Homolupane Derivatives Substituted in Position 17 and 22a. 1H NMR, 13C NMR and IR Spectra

Collection of Czechoslovak Chemical Communications, 1995
A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy.
Václav Křeček, Stanislav Hilgard, Miloš Buděšínský, Alois Vystrčil   +3 more
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IR and/or NMR Spectra-Structure Correlations for Organophosphorus Compounds

Applied Spectroscopy, 1988
IR and/or NMR spectra-structure correlations are presented which are useful in the identification of organophosphorus compounds.
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Experimental and theoretical study on IR and NMR spectra of several tetrachlorinated diphenyl sulfides

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011
Tetrachlorinated diphenyl sulfides (TCDPSs) are environmentally interesting compounds. In this paper, both experimental and theoretical studies on IR and (1)H NMR as well as (13)C NMR chemical shifts of 4 synthesized TCDPSs have been carried out.
Ruijuan, Qu, Xuesheng, Zhang, Qi, Zhang, Xi, Yang, Zunyao, Wang, Liansheng, Wang   +5 more
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High-resolution1H NMR and IR spectra of OH-groups of oxide catalysts

Reaction Kinetics and Catalysis Letters, 1985
Chemical shifts in high-resolution PMR spectra of hydroxyl groups of SiO2, Al2O3, aluminosilicate, phosphate and H-ZSM-5 zeolite catalysts have been measured and compared with IR spectroscopic data and proton charges calculated by the MINDO/3 method.
V. M. Mastikhin, I. L. Mudrakovskii, N. S. Kotsarenko, L. G. Karakchiev, A. G. Pelmenshchikov, K. I. Zamaraev   +5 more
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Density functional theory study on lactides: Geometries, IR, NMR and electronic spectra

Journal of Molecular Structure: THEOCHEM, 2007
Abstract Density functional theory (DFT) has been used to determine the equilibrium geometries, IR, total energies and NMR chemical shifts of various kinds of lactides. According to the calculations, besides l -lactide and d -lactide, three kinds of meso-lactides have been obtained: meso-i-lactide, meso-α-lactide and meso-β-lactide.
Wenpeng Wu, Wenbin Li, Lianbin Wang, Puyu Zhang, Jinglai Zhang   +4 more
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