Magnetic Resonance in Chemistry

Cover image for Vol. 51 Issue 12

December 2013

Volume 51, Issue 12

Pages 767–846

  1. Research articles

    1. Top of page
    2. Research articles
    3. MRC letters
    1. GIAO/DFT studies on 1,2,4-triazole-5-thiones and their propargyl derivatives (pages 767–774)

      Usha D. Phalgune, Kumar Vanka and P. R. Rajamohanan

      Version of Record online: 2 OCT 2013 | DOI: 10.1002/mrc.4012

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      GIAO calculations on 1,2,4-triazole thiones and their derivatives were carried out. The stability and shielding constants of tautomers/regioisomers was determined. Thermal energy and dipole moment values were used to determine relative populations. The tautomers/regioisomers present in solution were indentified, and shielding constants for those that could not be obtained experimentally were also calculated.

    2. Computational NMR coupling constants: Shifting and scaling factors for evaluating 1JCH (pages 775–787)

      J. San Fabián, J.M. García de la Vega, R. Suardíaz, M. Fernández-Oliva, C. Pérez, R. Crespo-Otero and R.H. Contreras

      Version of Record online: 10 OCT 2013 | DOI: 10.1002/mrc.4014

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      Density functional theory assessment for the determination of one-bond carbon–hydrogen spin–spin coupling constants is examined. Predictions using five functionals and nine basis sets are computed and compared with experimental values. The collection of 68 organic molecular systems with 88 coupling constants includes different types of hybridized carbon atoms. Regression analysis was used as a basic and appropriate methodology for this type of comparative study. B3P86/aug-cc-pVTZ-J yields good results for the studied set.

    3. Polymeric adducts of rhodium(II) tetraacetate with aliphatic diamines: natural abundance 13C and 15N CPMAS NMR investigations (pages 788–794)

      Jarosław Jaźwiński, Bohdan Kamieński and Agnieszka Sadlej

      Version of Record online: 4 OCT 2013 | DOI: 10.1002/mrc.4017

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      Polymeric adducts of rhodium(II) tetraacetate with aliphatic diamines have been investigated by means of 13C and 15N CPMAS NMR, and density functional theory calculations. Elemental analysis and NMR data revealed the axial coordination mode of ligands and the formation of regular (1 : 1)n oligomeric chains.

    4. Reduction of conformational mobility and aggregation in W60G β2-microglobulin: assessment by 15N NMR relaxation (pages 795–807)

      Devrim Gümral, Federico Fogolari, Alessandra Corazza, Paolo Viglino, Sofia Giorgetti, Monica Stoppini, Vittorio Bellotti and Gennaro Esposito

      Version of Record online: 18 OCT 2013 | DOI: 10.1002/mrc.4018

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      Compared 15N NMR relaxation and MD studies were performed for human β2-microglobulin, a protein responsible for a pathologic amyloid deposition, and the mutant with glycyne replacing the natural tryptophan at position 60. The results show that the mutant exhibits reduced aggregation with respect to the wild-type protein because of increased conformational rigidity, against the expectation for the introduction of a residue without side-chain. The assessed properties of the mutant are consistent with its reduced amyloidogenicity.

    5. A toolbox of HSQC experiments for small molecules at high 13C-enrichment. Artifact-free, fully 13C-homodecoupled and JCC-encoding pulse sequences (pages 808–814)

      Mohammadali Foroozandeh, Patrick Giraudeau and Damien Jeannerat

      Version of Record online: 14 OCT 2013 | DOI: 10.1002/mrc.4019

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      A set of HSQC experiments for 13C-enriched small molecules is presented. It includes artifact-free SE-HSQC and broadband 13C homodecoupled SE-HSQC sequences based on the Zangger–Sterk method. A high-sensitivity experiment based on frequency modulation and two sequences for the measurements of Jcc couplings are also presented.

    6. Experimental boundaries of the quantum rotor induced polarization (QRIP) in liquid state NMR (pages 815–820)

      Maik Icker, Pascal Fricke, Toni Grell, Julia Hollenbach, Henry Auer and Stefan Berger

      Version of Record online: 28 OCT 2013 | DOI: 10.1002/mrc.4021

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      The results of quantum rotor induced polarization for signal enhancement in liquid state NMR using a variety of different compounds are presented. Influencing factors such as cooling temperature and molecular environment have been investigated systematically.

    7. CRAFT (complete reduction to amplitude frequency table) – robust and time-efficient Bayesian approach for quantitative mixture analysis by NMR (pages 821–829)

      Krish Krishnamurthy

      Version of Record online: 24 OCT 2013 | DOI: 10.1002/mrc.4022

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      Combined application of digital filtering of regions of interest along with Bayesian approach for time-domain analysis is demonstrated to be an efficient and robust approach for quantitative NMR. Frequency-amplitude tables generated directly from the FID can be used along with fingerprint chemical shifts for quantitative analysis of complex mixtures.

  2. MRC letters

    1. Top of page
    2. Research articles
    3. MRC letters
    1. 1H and 13C NMR investigation of 20-hydroxyecdysone dioxolane derivatives, a novel group of MDR modulator agents (pages 830–836)

      Attila Balázs, Attila Hunyadi, József Csábi, Nikoletta Jedlinszki, Ana Martins, András Simon and Gábor Tóth

      Version of Record online: 2 OCT 2013 | DOI: 10.1002/mrc.4015

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      The synthesis, structure elucidation and the complete 1H and 13C signal assignment of a series of dioxolane derivatives of 20-hydroxyecdysone, synthesized as novel modulators of multidrug resistance, are presented. The structures and NMR signal assignment were established by comprehensive one-dimensional and two-dimensional NMR spectroscopy supported by mass spectrometry.

    2. 1H and 13C NMR assignments of bioactive indeno[1,2-b]indole-10-one derivatives (pages 837–841)

      Faten Al Chab, Bernard Fenet, Marc Le Borgne, Joachim Jose, Noël Pinaud, Jean Guillon and Laurent Ettouati

      Version of Record online: 2 OCT 2013 | DOI: 10.1002/mrc.4016

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      Complete 1H and 13C assignments of eight bioactive indeno[1,2-b]indole-10-one derivatives were accomplished by the combined use of one-dimensional and two-dimensional NMR experiments.

    3. Four new prenylated flavonoids from the roots of Cudrania tricuspidata (pages 842–846)

      Liuyuan Chen, Yinghui Duan, Chang Li, Yu Wang, Xupeng Tong, Yi Dai and Xinsheng Yao

      Version of Record online: 14 OCT 2013 | DOI: 10.1002/mrc.4020

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      Four new prenylated flavonoids were isolated from the roots of Cudrania tricuspidata. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic techniques.

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