Magnetic Resonance in Chemistry

Cover image for Vol. 51 Issue 1

January 2013

Volume 51, Issue 1

Pages 1–68

  1. Rapid Communication

    1. Top of page
    2. Rapid Communication
    3. Research Articles
    4. MRC Letters
    1. Disordering of phospholipid headgroups induced by a small amount of polyethylene oxide (pages 1–3)

      Andrey Filippov, Bulat Munavirov, Bulat Gizatullin and Oleg N. Antzutkin

      Version of Record online: 7 NOV 2012 | DOI: 10.1002/mrc.3900

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      A new component in the 31P NMR spectra appeared only with addition of a small fraction of PEO (up to one PEO segment per DMPC molecule) and disappeared when larger amounts of PEO were added. We explained this phenomenon as an effect of an inhomogeneous force field induced by the PEO molecules located at a certain depth in the lipid membrane interface region.

  2. Research Articles

    1. Top of page
    2. Rapid Communication
    3. Research Articles
    4. MRC Letters
    1. 35Cl NQR frequency and spin lattice relaxation time in 3,4-dichlorophenol as a function of pressure and temperature (pages 4–8)

      L. Ramu, K. P. Ramesh and R. Chandramani

      Version of Record online: 15 NOV 2012 | DOI: 10.1002/mrc.3885

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      3,4-Dichlorophenol reveals two NQR signals throughout the pressure range studied. The torsional frequencies obtained at 300K by NQR data have been compared with the value obtained by Far-IR spectra. A nonlinear variation of NQR frequency with pressure has been observed & the pressure coefficients were observed to be positive.

    2. 1H NMR spectra. Part 29§: proton chemical shifts and couplings in esters—the conformational analysis of methyl γ-butyrolactones (pages 9–15)

      Raymond J. Abraham and Paul Leonard

      Version of Record online: 5 NOV 2012 | DOI: 10.1002/mrc.3896

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      The 1H spectra of 35 esters are analysed and their 1H shifts reproduced by a semi-empirical model. The conformer equilibria of the three methyl g-butyrolactones were obtained from the observed HH coupings. DG(ax-eq) values of 1.0, 0.34 and 0.65 kcal/mol were found for the 2,3 and 4 methyl compounds res.

    3. Unambiguous structure elucidation of heterocyclic products from condensation–cyclisation reactions of enaminones by 2D INADEQUATE and 15N NMR (pages 16–18)

      Johannes C. Liermann, Mohamed Hilmy Elnagdi and Herbert Meier

      Version of Record online: 7 NOV 2012 | DOI: 10.1002/mrc.3897

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      The reaction of enaminones with 3-amino-2-cyanopent-2-enedinitrile can lead to an array of 12 possible products, depending on the reaction pathway and tautomerization. The use of 2D INADEQUATE and 15N NMR for the unambiguous structure elucidation of the reaction products is discussed in this manuscript.

    4. You have full text access to this OnlineOpen article
      Host–guest complexes between cryptophane-C and chloromethanes revisited (pages 19–31)

      Z. Takacs, M. Soltesova, J. Kowalewski, J. Lang, T. Brotin and J.-P. Dutasta

      Version of Record online: 7 NOV 2012 | DOI: 10.1002/mrc.3898

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      Cryptophane-C is composed of two non-equivalent cyclotribenzylene caps, connected by three OCH2CH2O linkers in an anti arrangement. Host-guest complexes of cryptophane-C with dichloromethane and chloroform in solution were investigated by variable temperature proton and carbon-13 spectra, exchange/cross relaxation spectroscopy, line shape analysis and 13C relaxation measurements. The NMR work was supported by quantum chemical calculations. Combining different types of evidence led to a detailed picture of molecular recognition, interpreted in terms of conformational selection.

    5. 1H NMR spectra of ethane-1,2-diol and other vicinal diols in benzene: GIAO/DFT shift calculations (pages 32–41)

      John S. Lomas

      Version of Record online: 20 NOV 2012 | DOI: 10.1002/mrc.3899

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      Proton NMR shifts and coupling constant are measured for several vicinal diols in benzene; the shifts are well reproduced by GIAO/DFT calculations based on the Gaussian 09 solvation model.

    6. Eu(fod)3 binding on the 1H-NMR spectra of bis(2′-ethylbenzoate)ethylene glycol podands (pages 42–45)

      Cüneyt H. Ünlü, Gönül Yapar and Çakıl Erk

      Version of Record online: 22 NOV 2012 | DOI: 10.1002/mrc.3904

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      Observation of the complexing of Eu(fod)3 with bis(2′-ethylbenzoate)ethylene glycol podands having one, two, three, and four oxyethylene groups using 1H-NMR spectra and estimation of selective binding constants at 295 K in CDCl3

    7. Solvent effects on 15N NMR coordination shifts (pages 46–53)

      Roland Kleinmaier, Sven Arenz, Alavi Karim, Anna-Carin C. Carlsson and Máté Erdélyi

      Version of Record online: 4 DEC 2012 | DOI: 10.1002/mrc.3907

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      15N NMR coordination shifts (observed upon complexation of metal cations by N-ligands) have frequently been proposed as a measure of coordination strength. We found a strong dependence of Δ15Ncoord on solvent and substituents both experimentally and in density functional theory calculations. Our results show that nitrogen ligands can only be compared by way of Δ15Ncoord if the latter were determined in the same solvent and considering possible anion interactions.

    8. Structure verification through computer-assisted spectral assignment of NMR spectra (pages 54–59)

      Bertrand Plainchont and Jean-Marc Nuzillard

      Version of Record online: 4 DEC 2012 | DOI: 10.1002/mrc.3908

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      The molecular structure of an organic molecule is considered valid if the 13C NMR resonances can be assigned on the basis of the 2D HSQC, HMBC and COSY data and if the predicted chemical shift values fit well with the experimental ones. The chemical shift assignment of a published structure leads to its revision.

  3. MRC Letters

    1. Top of page
    2. Rapid Communication
    3. Research Articles
    4. MRC Letters
    1. Observation of two N2-isobutyrylguanine tautomers by NMR spectroscopy (pages 60–64)

      Lijing Yang, Jia Li, Razvan Simionescu and Hongbin Yan

      Version of Record online: 20 NOV 2012 | DOI: 10.1002/mrc.3901

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      The 1,7-dihydro- and 1,9-dihydro-prototropic tautomers of N2-isobutyrylguanine were observed in virtually 1:1 ratio in dichloromethane-dimethyl sulfoxide by NMR spectroscopy. This tautomeric equilibrium was found to be highly solvent dependent, particularly on the water content.

    2. Three new xanthone derivatives from an algicolous isolate of Aspergillus wentii (pages 65–68)

      Ran-Ran Sun, Feng-Ping Miao, Jing Zhang, Gang Wang, Xiu-Li Yin and Nai-Yun Ji

      Version of Record online: 22 NOV 2012 | DOI: 10.1002/mrc.3903

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      Three new xanthones (1–3) from the cultures of algicolous Aspergillus wentii were characterized by 1D and 2D NMR as well as quantum chemical calculations.

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