Magnetic Resonance in Chemistry

Cover image for Vol. 54 Issue 6

Early View (Online Version of Record published before inclusion in an issue)

Impact Factor: 1.179

ISI Journal Citation Reports © Ranking: 2014: 30/44 (Spectroscopy); 94/157 (Chemistry Multidisciplinary); 107/139 (Chemistry Physical)

Online ISSN: 1097-458X


  1. 1 - 57
  1. Letter - spectral assignments

    1. Trametramide A, a new pyridone alkaloid from the fungus Trametes trogii TGC-P-3

      Xiqing Bian, Jiao Bai, Ke Sun, Shengdong Huang, Kaibo Wang, Shuang Tang, Chunmei Xue, Gaosheng Hu, Xin Wu, Huiming Hua and Yuehu Pei

      Version of Record online: 22 MAY 2016 | DOI: 10.1002/mrc.4451

  2. Research articles

    1. Prediction of beef color using time-domain nuclear magnetic resonance (TD-NMR) relaxometry data and multivariate analyses

      Luiz Felipe Pompeu Prado Moreira, Adriana Cristina Ferrari, Tiago Bueno Moraes, Ricardo Andrade Reis, Luiz Alberto Colnago and Fabíola Manhas Verbi Pereira

      Version of Record online: 19 MAY 2016 | DOI: 10.1002/mrc.4456

      Thumbnail image of graphical abstract

      Time-domain NMR spectroscopy has been used to predict several technological parameters to assess meat quality. These analyses are based on the decay of NMR signal Carr-Purcell-Meiboom-Gill pulse sequence that depends on transverse relaxation time (T2). By means of multivariate models is also feasible to measure color in beef samples with robustness and speed, independent of the sample size.

  3. Feature article tutorials

    1. The fundamentals behind solving for unknown molecular structures using computer-assisted structure elucidation: a free software package at the undergraduate and graduate levels

      Arvin Moser and Brent G. Pautler

      Version of Record online: 15 MAY 2016 | DOI: 10.1002/mrc.4453

      Thumbnail image of graphical abstract

      This paper covers various exercises of using a free computer-assisted structure elucidation (CASE) software application ‘Structure Elucidator’. The purpose of these exercises is to use elucidation software to quickly explore potential candidates given a set of NMR data and a molecular formula. The learning process is similar to learning to use a mathematical calculator for a math problem.

  4. Research articles

    1. 1H and 13C NMR spectral assignment of N,N′-disubstituted thiourea and urea derivatives active against nitric oxide synthase

      Mariem Chayah, M. Encarnación Camacho, M. Dora Carrión and Miguel A. Gallo

      Version of Record online: 12 MAY 2016 | DOI: 10.1002/mrc.4455

      Thumbnail image of graphical abstract

      The 1H and 13C NMR resonances of a series of N,N'-disubstituted thiourea and urea derivatives were completely and unequivocally assigned using the concerted application of one- and two-dimensional experiments (DEPT, HSQC and HMBC, both carbon and nitrogen). NOESY experiments have confirmed the preferred conformation of these molecules.

    2. Normal halogen dependence of 13C NMR chemical shifts of halogenomethanes revisited at the four-component relativistic level

      Dmitry O. Samultsev, Yury Yu. Rusakov and Leonid B. Krivdin

      Version of Record online: 11 MAY 2016 | DOI: 10.1002/mrc.4452

      Thumbnail image of graphical abstract

      The ‘Normal Halogen Dependence’ of 13C NMR chemical shifts in the series of halogenomethanes is revisited at the four-component relativistic level. Calculations of 13C NMR chemical shifts of 70 halogenomethanes have been carried out at the DFT and MP2 levels with taking into account relativistic effects using the four-component relativistic theory of Dirac-Coulomb within the different computational methods (4RPA, 4OPW91) and hybrid computational schemes (MP2 + 4RPA, MP2 + 4OPW91).

  5. Special issue research articles

    1. Application of CRAFT in two-dimensional NMR data processing

      Krish Krishnamurthy, Andrea M. Sefler and David J. Russell

      Version of Record online: 10 MAY 2016 | DOI: 10.1002/mrc.4449

      Thumbnail image of graphical abstract

      Two-dimensional data are typically truncated in the indirect dimension and require the use of apodization functions prior to Fourier transform. The line broadening induced by such apodization significantly masks peak resolution. Complete reduction to amplitude frequency table processing of time-domain data requires minimal or no apodization and yields much narrower spectral line widths of resonances by circumventing the loss of resolution due to apodization.

  6. Research articles

    1. Heating and temperature gradients of lipid bilayer samples induced by RF irradiation in MAS solid-state NMR experiments

      Jing Wang, Zhengfeng Zhang, Weijing Zhao, Liying Wang and Jun Yang

      Version of Record online: 9 MAY 2016 | DOI: 10.1002/mrc.4450

      Thumbnail image of graphical abstract

      Using the 1H chemical shifts of water, we characterized RF heating as functions of hydration levels and salt concentrations in three liposomes in MAS NMR experiments. The maximum temperature elevation was about 10 °C, but the temperature gradient across the sample was up to 20 °C.

  7. Letter - correspondence

    1. A new approach to the optimisation of non-uniform sampling schedules for use in the rapid acquisition of 2D NMR spectra of small molecules

      Philip J. Sidebottom

      Version of Record online: 9 MAY 2016 | DOI: 10.1002/mrc.4444

      Thumbnail image of graphical abstract

      Non-uniform sampling allows the routine, rapid acquisition of 2D NMR data. When the number of points in the NUS schedule is low, the quality of the data obtained is very dependent of the schedule used. A simple proceedure for finding optimium schedules has been developed and is demonstrated for the multiplicity edited HSQC experiment.

  8. Letter - spectral assignments

    1. A new lignan from Zygophyllum aegyptium

      Ahmed A. Zaki, Zulfiqar Ali, Yasser A. El-Amier and Ikhlas A. Khan

      Version of Record online: 1 MAY 2016 | DOI: 10.1002/mrc.4446

  9. Research articles

    1. DNP sensitivity of 19F-NMR signals in hexafluorobenzene depending on polarizing agent type

      Ahmet Peksoz

      Version of Record online: 1 MAY 2016 | DOI: 10.1002/mrc.4445

      Thumbnail image of graphical abstract

      19F-NMR signals of hexafluorobenzene were observed with low-field dynamic nuclear polarization using nitroxide, BDPA, MC800 and MC30 asphaltene polarizing agents. The couplings between hexafluorobenzene and each polarizing agent were determined to be predominantly scalar. The study also reports the possible reasons why 19F-NMR signal of hexafluorobenzene is very sensitive to the free radical type by using dynamic nuclear polarization parameters and some quantum chemical calculations.

    2. Solid-state 13C, 15N and 29Si NMR characterization of block copolymers with CO2 capture properties

      Faiz Ullah Shah, Farid Akhtar, Muhammad Saif Ullah Khan, Zareen Akhter and Oleg N. Antzutkin

      Version of Record online: 1 MAY 2016 | DOI: 10.1002/mrc.4440

      Thumbnail image of graphical abstract

      A solid-state multinuclear (13C, 15N and 29Si) magic-angle spinning NMR spectroscopy was used to characterize three block copolymers based on polyamide and dimethylsiloxane and two polyamides one of which containing ferrocene. The block copolymers have shown a reversible CO2 capture capacity as solid sorbents at atmospheric pressure. The polymeric materials can be regenerated without application of heat and re-used for a number of CO2 adsorption–desorption cycles.

  10. Letter - spectral assignments

    1. A theoretical and experimental NMR study of BODIPY 493/503: difluoro{2-[1-(3,5-dimethyl-2H-pyrrol-2-ylidene-N)ethyl]-3,5-dimethyl-1H-pyrrolato-N}boron

      María Luisa Jimeno, María Teresa Benito, Elisa García Doyagüez, Rosa M. Claramunt, Dionisia Sanz, Marta Marín-Luna, Ibon Alkorta and José Elguero

      Version of Record online: 1 MAY 2016 | DOI: 10.1002/mrc.4438

  11. Research articles

    1. How to measure absolute P3HT crystallinity via 13C CPMAS NMR

      Ryan C. Nieuwendaal

      Version of Record online: 20 APR 2016 | DOI: 10.1002/mrc.4443

      Thumbnail image of graphical abstract

      13C CPMAS NMR can be used to measure crystallinity in P3HT, the most ubiquitous polymer for organic electronics, with TH spectral editing under slow MAS. Side-chain dynamics control the experimental 13C CPMAS parameters, which is demonstrated via variable temperature 1H NMR.

  12. Special issue letter - spectral assignments

    1. Computer-assisted 1H NMR analysis of the anti-tuberculosis drug lead ecumicin

      Wei Gao, José G. Napolitano, David C. Lankin, Jin-Yong Kim, Ying-Yu Jin, Hanki Lee, Joo-Won Suh, Shao-Nong Chen and Guido F. Pauli

      Version of Record online: 19 APR 2016 | DOI: 10.1002/mrc.4425

  13. Research articles

    1. Flavonoid glycosides from Persea caerulea. Unraveling their interactions with SDS-micelles through matrix-assisted DOSY, PGSE, mass spectrometry, and NOESY

      Juan M. Álvarez, Álvaro Raya-Barón, Pedro M. Nieto, Luis E. Cuca, Alegría Carracso-Pancorbo, Alberto Fernández-Gutiérrez and Ignacio Fernández

      Version of Record online: 13 APR 2016 | DOI: 10.1002/mrc.4434

      Thumbnail image of graphical abstract

      Two compounds, kaempferol-3-O-rhamnopyranoside (1) and quercetin-3-O-arabinofuranoside (2), have been isolated for the first time from leaves of Persea caerulea. Matrix-assisted diffusion ordered spectroscopy (DOSY) and pulse field gradient spin echo (PGSE) have been applied to exploit differential binding to separate the NMR signals. Calculated average inter-proton distances derived from one-dimensional nuclear Overhauser spectroscopy σ values revealed a differential insertion of both flavonoid glycosides into the micelles.

    2. Use of glass capillaries to suppress thermal convection in NMR tubes in diffusion measurements

      Takashi Iwashita, Tsuyoshi Konuma, Erisa Harada, Shoko Mori and Kenji Sugase

      Version of Record online: 12 APR 2016 | DOI: 10.1002/mrc.4437

      Thumbnail image of graphical abstract

      We developed a new method to effectively suppress thermal convection using glass capillaries. A total of 6 to 18 capillaries (0.8-mm outer diameter) were inserted into a regular 5-mm NMR tube. The capillaries had minimal effect on magnetic field homogeneity and enabled us to obtain clean DOSY spectra of a mixture of small organic compounds.

  14. Rapid communications

    1. A general chemical shift decomposition method for hyperpolarized 13C metabolite magnetic resonance imaging

      Jian-xiong Wang, Matthew E. Merritt, Dean Sherry and Craig R. Malloy

      Version of Record online: 5 APR 2016 | DOI: 10.1002/mrc.4435

      Thumbnail image of graphical abstract

      A generalized chemical shift decomposition method incorporating a single-shot spiral imaging sequence based on Dixon method is described. This method retains as much spin polarization as possible while allowing detection of metabolites that have a wide range of chemical shift values. The method was demonstrated both in phantoms and in vivo using hyperpolarized [1-13C]pyruvate.

  15. Research articles

    1. Through-space 19F–15N couplings for the assignment of stereochemistry in flubenzimine

      Ion Ghiviriga, Miles A. Rubinski and William R. Dolbier Jr

      Version of Record online: 5 APR 2016 | DOI: 10.1002/mrc.4407

      Thumbnail image of graphical abstract

      Through-space 19F-15N couplings revealed the configuration of Flubenzimine, with the CF3 group on N4 pointing towards the lone pair of N5. The 19F-15N coupling constants were measured at natural abundance using a spin-state selective indirect-detection pulse sequence.

  16. Letter - spectral assignments

    1. Structure elucidation and NMR assignments of daldinone E and rickenyl F from the fungus Hypoxylon sp. DWS T-P-6

      Hong Xia Shi, Bao Min Feng, Gang Chen, Jiao Bai, Hui Ming Hua, Dan Zhao, Hai Feng Wang and Yue Hu Pei

      Version of Record online: 29 MAR 2016 | DOI: 10.1002/mrc.4429

  17. Perspectives

    1. Parallel NMR spectroscopy with simultaneous detection of 1H and 19F nuclei

      Helena Kovacs and Ēriks Kupče

      Version of Record online: 29 MAR 2016 | DOI: 10.1002/mrc.4428

      Thumbnail image of graphical abstract

      Recording NMR signals of several nuclear species simultaneously by using parallel receivers provides more information from a single measurement and at the same time increases the measurement sensitivity per unit time. Here we present a comprehensive series of the most frequently used NMR experiments modified for simultaneous direct detection of two of the most sensitive NMR nuclei – 1H and 19F. We hope that the presented material will stimulate interest in and further development of this technique.

  18. Special issue research articles

    1. Na+ and solute diffusion in aqueous channels of Myverol bicontinuous cubic phase: PGSE NMR and computer modelling

      Timothy J. Larkin, Christopher J. Garvey, Dmitry Shishmarev, Philip W. Kuchel and Konstantin I. Momot

      Version of Record online: 22 MAR 2016 | DOI: 10.1002/mrc.4432

      Thumbnail image of graphical abstract

      Molecular diffusion in the aqueous channels of a lipid/water bicontinuous cubic phase was investigated using NMR and interpreted with the aid of Monte Carlo random walk simulations. The results inform quantitative modelling of the controlled release of hydrophilic drugs from cubosomes.

  19. Research articles

    1. Transfer of multivariate regression models between high-resolution NMR instruments: application to authenticity control of sunflower lecithin

      Yulia B. Monakhova and Bernd W. K. Diehl

      Version of Record online: 22 MAR 2016 | DOI: 10.1002/mrc.4433

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      A problem of data standardization exists, when multivariate model has to be applied to the spectra recorded on a secondary NMR spectrometer. Standardization methods, especially piecewise direct standardization, successfully perform partial least square calibration transfer between NMR devices with different configurations regarding quantitative assessment of lecithin vegetable origin.

    2. ESR study of molecular orientation and dynamics of TEMPO derivatives in CLPOT 1D nanochannels

      Hirokazu Kobayashi, Yuta Furuhashi, Haruka Nakagawa and Tetsuo Asaji

      Version of Record online: 21 MAR 2016 | DOI: 10.1002/mrc.4423

      Thumbnail image of graphical abstract

      The molecular orientations and dynamics of 2,2,6,6-tetramethyl-1-piperidinyloxyl derivatives in 2,4,6-tris(4-chlorophenoxy)-1,3,5-triazine 1D nanochannels were examined using electron spin resonance. At higher temperatures, the guest radicals in each inclusion compound underwent anisotropic rotational diffusion in the nanochannels. The rotational diffusion activation energy or molecular orientation in the nanochannels of each guest radical was independent of the size and type of substituent group of the radical or spacer molecules.

    3. Molecular dynamics and composition of crude oil by low-field nuclear magnetic resonance

      Zijian Jia, Lizhi Xiao, Zhizhan Wang, Guangzhi Liao, Yan Zhang and Can Liang

      Version of Record online: 17 MAR 2016 | DOI: 10.1002/mrc.4424

      Thumbnail image of graphical abstract
      • Use relaxation to analyze composition of crude oil by 2D low-field NMR.
      • Probing asphaltene aggregation in crude oils with low-field NMR.
      • Low-field NMR provided the molecule dynamics of crude oil.
    4. Development of nitroxide-based theranostic compounds that act both as anti-inflammatory drugs and brain redox imaging probes in MRI

      Miho C. Emoto, Shingo Sato and Hirotada G. Fujii

      Version of Record online: 15 MAR 2016 | DOI: 10.1002/mrc.4431

      Thumbnail image of graphical abstract

      Two nitroxide-based theranostic probes, ibuprofen-PROXYL and ketoprofen-PROXYL, were synthesized for MRI and anti-inflammatory drug effect. These theranostic probes were able to suppress nitric oxide production and pass the blood-brain barrier, resulting in T1 contrast enhancement in mouse brain. These results indicate that they can act as both blood-brain barrier-permeable redox-sensitive contrast agents in magnetic resonance imaging and as an anti-inflammatory drug in septic mouse brain.

    5. Prediction of 195Pt NMR chemical shifts of dissolution products of H2[Pt(OH)6] in nitric acid solutions by DFT methods: how important are the counter-ion effects?

      Athanassios C. Tsipis and Ioannis N. Karapetsas

      Version of Record online: 14 MAR 2016 | DOI: 10.1002/mrc.4426

      Thumbnail image of graphical abstract

      Accurate 195Pt chemical shifts for the complete series of dissolution products of H2[Pt(OH)6] in aqueous nitric acid solutions are predicted by density functional theory methods. The GIAO-PBE0/SARC–ZORA(Pt) ∪ BS(E)/Polarizable Continuum Model [BS(E) = 6–31 + G(d) or 6–31G(d,p); E = N, O, H] computational protocols are the best performers. Counter-anion effects are very important for the accurate prediction of the 195Pt NMR chemical shifts, while counter-cation effects are less important.

  20. Letter - spectral assignments

  21. Special issue research articles

    1. Probing sol-gel matrices microenvironments by PGSE HR-MAS NMR

      Ana S. D. Ferreira, Susana Barreiros and Eurico J. Cabrita

      Version of Record online: 14 MAR 2016 | DOI: 10.1002/mrc.4427

      Thumbnail image of graphical abstract

      Pulsed Gradient Spin Echo diffusion with high-resolution magic angle spinning NMR was used to study transport properties of solvents with different polarities (1-pentanol, acetonitrile and n-hexane) in sol-gel matrices. A comprehensive analysis of the diffusional behaviour allowed us to gain insight into the interpore and intrapore chemical microenvironment, thus providing crucial information for the rationalization and optimization of sol-gel materials for biocatalysis application.

  22. Research articles

    1. Ultra-high resolution band-selective HSQC for nanomole-scale identification of chlorine-substituted 13C in natural products drug discovery

      Xiao Wang, Brendan M. Duggan and Tadeusz F. Molinski

      Version of Record online: 7 MAR 2016 | DOI: 10.1002/mrc.4415

      Thumbnail image of graphical abstract

      Ultra-high resolution band-selective HSQC was refined to detect 35Cl–37Cl isotope shifts in 1H–13C crosspeaks of chlorinated CH. The scope and limitations, including optimum experimental parameters for detection of isotope shifts induced in 13C (Dd), were explored by measurements of five chlorinated compounds, including polychlorinated natural products from the red alga, Plocamium cartilagineum from California.

    2. The 1H NMR spectrum of pyrazole in a nematic phase

      Patricio Provasi, María Luisa Jimeno, Ibon Alkorta, Felipe Reviriego, José Elguero and Jukka Jokisaari

      Version of Record online: 6 MAR 2016 | DOI: 10.1002/mrc.4422

      Thumbnail image of graphical abstract

      Because of the rapid exchange between two tautomers, the orientational order of 1H-pyrazole in a thermotropic liquid crystal solution can be described by a single parameter.

    3. Quantitation of memantine hydrochloride bulk drug and its tablet formulation using proton nuclear magnetic resonance spectrometry

      Archana Sahu, Mallikarjun Narayanam, Moolchand Kurmi, Mayurbhai Kathadbhai Ladumor and Saranjit Singh

      Version of Record online: 28 FEB 2016 | DOI: 10.1002/mrc.4421

      Thumbnail image of graphical abstract

      The use of quantitative nuclear magnetic resonance (NMR) spectrometry for the determination of non-UV active memantine hydrochloride with relative simplicity and precision has been demonstrated in this investigation. The study highlighted possibility of direct determination of memantine hydrochloride in pure form and its marketed tablets, without need of derivatization as is the requirement in HPLC studies.

  23. Special issue research articles

    1. WaterControl: self-diffusion based solvent signal suppression enhanced by selective inversion

      Gang Zheng, Allan M. Torres and William S. Price

      Version of Record online: 28 FEB 2016 | DOI: 10.1002/mrc.4420

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      The WaterControl technique was developed by inserting a (pulsed gradient – selective inversion pulse – pulsed gradient) unit into each ‘transverse’ period of a standard stimulated echo pulse sequence so that the coherence transfer pathways corresponding to both suppression and non-suppression regions can be selected in one transient. The new sequence affords a diffusion-based and quantifiable solvent signal suppression with no or minimal loss of features of interest.

    2. In-tube derivatization for determination of absolute configuration and enantiomeric purity of chiral compounds by NMR spectroscopy

      Jinhai Gao, Srinivasan Rajan and Bing Wang

      Version of Record online: 25 FEB 2016 | DOI: 10.1002/mrc.4419

      Thumbnail image of graphical abstract

      A fast and efficient in-tube derivatization method using commercially available polymer-supported coupling agents was developed to prepare chiral derivatizing agent derivatives of chiral compounds directly in NMR tube without any workup or purification. The method allows quick NMR analysis of chiral compounds at microscale level.

    3. Anisotropic diffusion in stretched hydrogels containing erythrocytes: evidence of cell-shape distortion recorded by PGSE NMR spectroscopy

      Dmitry Shishmarev, Konstantin I. Momot and Philip W. Kuchel

      Version of Record online: 23 FEB 2016 | DOI: 10.1002/mrc.4416

      Thumbnail image of graphical abstract

      A method for the tuneable elongation of human red blood cells (RBCs) was developed. Morphological changes in RBCs were investigated by quantifying molecular diffusion of water by PGSE NMR spectroscopy.

    4. Quadrupole interactions: NMR, NQR, and in between from a single viewpoint

      Alex D. Bain

      Version of Record online: 17 FEB 2016 | DOI: 10.1002/mrc.4418

      Thumbnail image of graphical abstract

      Nuclear spins can have two strong interactions: quadrupolar (zero magnetic field) and Zeeman (high field). The diagram shows the energy levels of a spin-3/2 in these two extremes. In this paper we explore the intermediate regime and show how to describe the whole range with a single theoretical approach.

  24. Special issue letter - application notes

    1. Identification of by-products in support of process development of Muraglitazar

      Charles Pathirana, Andrew Rusowicz, Russell Suda, Shankar Swaminathan and Venkatapuram Palaniswamy

      Version of Record online: 17 FEB 2016 | DOI: 10.1002/mrc.4412

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      Process optimization in pharmaceutical development includes minimization of by-products. Identification of by-products is accomplished by using NMR in combination with mass spectrometry. This is illustrated using the by-products encountered in the development of muraglitazar (1).

  25. Special issue mini-reviews

    1. Applications of NMR diffusion methods with emphasis on ion pairing in inorganic chemistry: a mini-review

      Paul S. Pregosin

      Version of Record online: 17 FEB 2016 | DOI: 10.1002/mrc.4394

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      Applications of diffusion constants in the connection with estimating molecular weights in solution, recognizing hydrogen bonding, encapsulation processes and, primarily, identifying and estimating the degree of ion pairing in inorganic chemistry.

  26. Letter - spectral assignments

    1. The synthesis, structural elucidation and antimicrobial activity of 2- and 4-substituted-coumarinyl chalcones

      Thrineshen Moodley, Mehbub Momin, Chunderika Mocktar, Christina Kannigadu and Neil A. Koorbanally

      Version of Record online: 11 FEB 2016 | DOI: 10.1002/mrc.4414

  27. Research articles

    1. Spatial location of indomethacin associated with unimeric amphiphilic carrier macromolecules as determined by nuclear magnetic resonance spectroscopy

      David E. Orban, Alysha Moretti and Kathryn E. Uhrich

      Version of Record online: 11 FEB 2016 | DOI: 10.1002/mrc.4401

      Thumbnail image of graphical abstract

      Unimeric amphiphilic carrier molecules are shown to encapsulate approximately four indomethacin molecules per carrier, as demonstrated using nuclear magnetic resonance spectroscopy techniques. The indomethacin molecules preferentially localize to the interfacial region and are retained in organic and aqueous conditions.

  28. Special issue research articles

    1. NMR study of the influence of n-alkanol co-surfactants on reverse micelles in quaternary microemulsions of cetyltrimethylammonium bromide (CTAB)

      Amanda J. Mills and Melanie M. Britton

      Version of Record online: 8 FEB 2016 | DOI: 10.1002/mrc.4392

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      NMR measurements of diffusion and relaxation have shown that the alkanol co-surfactant in CTAB/n-alkane/alkanol/water reverse microemulsions exchanges between the reverse micelle and continuous phase on the millisecond timescale. Reverse micelles in the CTAB/n-hexane/pentanol/water microemulsion are found to exhibit a bimodal distribution of droplet sizes, which becomes unimodal after several hours, producing larger reverse micelles than those formed with the other co-surfactants. Molecular modeling showed the RMs in CTAB/n-hexane/alkanol/water microemulsions are not spherical, with those formed with pentanol the least spherical.

  29. Research articles

    1. Generic applications of 13C-detected NMR diffusion to formulated systems with suppression of thermal convection induced by proton decoupling

      Jianbo Hou, Yiyong He, Paolo Sabatino, Ling Yuan and David Redwine

      Version of Record online: 4 FEB 2016 | DOI: 10.1002/mrc.4404

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      Effective suppression of thermal convection effect is critical to enable robust applications of 13C-detected diffusion to formulated systems in general.

  30. Special issue research articles

    1. Isolation and structure elucidation of unexpected in-process impurities during tetrazole ring formation of an investigational drug substance

      Maria Victoria Silva Elipe, Chul Yoo, Fang Xia, Jason Simiens, Kevin Crossley, John R. Huckins, Hong-Xun Guo, Jason Tedrow and Kirby Wong-Moon

      Version of Record online: 3 FEB 2016 | DOI: 10.1002/mrc.4413

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      Two in-process impurities of identical protonated mass of ca. 577.32 Da and fragmentation patterns were observed during the formation of the tetrazole ring in an intermediate of an investigational drug. A multi-step isolation procedure from the mother liquor of the reaction was performed for structural elucidation. NMR indicated the presence of an additional NH functional group in both isolates with similar spatial and bond correlations. The unexpected formation of a benzodimethylcarbamoylamino moiety appears to be resulting from a ‘Schmidt-like’ reaction.

  31. Research articles

    1. Characterization of novel isobenzofuranones by DFT calculations and 2D NMR analysis

      Milena G. Teixeira and Elson S. Alvarenga

      Version of Record online: 26 JAN 2016 | DOI: 10.1002/mrc.4411

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      Phthalides are frequently found in naturally occurring substances and exhibit a broad spectrum of biological activities. In the search for compounds with insecticidal activity, phthalides have been used as versatile building blocks for the syntheses of novel potential agrochemicals. The endo Diels–Alder adduct (2) was brominated to afford two novel unforeseen compounds, which were characterized by comparing the experimental and theoretical 1H and 13C chemical shifts by mean absolute error and DP4 probability analyses.

  32. Letter - spectral assignments

    1. Structure determination of two new nerolidol-type sesquiterpenoids from the soil actinomycete Streptomyces scopuliridis

      Liya Li, Ruohan Liu, Li Han, Yi Jiang, Jiang Liu, Yuanyuan Li, Chunhui Yuan and Xueshi Huang

      Version of Record online: 18 JAN 2016 | DOI: 10.1002/mrc.4409

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      Two new nerolidol-type sesquiterpenes were isolated from the culture broth of Streptomyces scopuliridis, and identified based on 1D and 2D NMR spectroscopic data analyses.

  33. Research articles

    1. Distinguishing rotamers in N-trifluoroacetyl-3-benzazepine derivatives

      Williams A. Acevedo-Fuentes and Bruce K. Cassels

      Version of Record online: 13 JAN 2016 | DOI: 10.1002/mrc.4406

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      This paper provides the full 13C NMR assignments for the trifluoroacetamides of five potentially appetite-reducing 5-HT2C benzazepine receptor agonists and two open-ring synthetic precursors. These compounds exist in solution as mixtures of two rotamers for each of which the 13C NMR signals have now been assigned with the assistance of 2D NMR experiments and the carbonyl-induced shifts of the neighboring 13CH2 resonances and long-range 13C/19F couplings.

  34. Special issue research articles

    1. Di(ethylene glycol) methyl ether methacrylate (DEGMEMA)-derived gels align small organic molecules in methanol

      Manuela E. García, Shannon R. Woodruff, Erich Hellemann, Nicolay V. Tsarevsky and Roberto R. Gil

      Version of Record online: 13 JAN 2016 | DOI: 10.1002/mrc.4400

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      In this study, di(ethylene glycol) methyl ether methacrylate (DEGMEMA)-based gels are introduced as alignment media for the measurement of RDCs of small organic molecules in polar solvents such as methanol. The low viscosity of methanol permits the execution of J- scaled BIRD HSQC experiments that yield very sharp lines in anisotropic conditions. The gels have excellent mechanical properties and performance demonstrated by analyzing the structure of the alkaloid retrorsine.

  35. Research articles

    1. Conformation analysis of d-glucaric acid in deuterium oxide by NMR based on its JHH and JCH coupling constants

      Yukiko Enomoto-Rogers, Hisaharu Masaki, Tetsuya Ito, Kazuo Furihata and Tadahisa Iwata

      Version of Record online: 8 JAN 2016 | DOI: 10.1002/mrc.4396

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      Conformation of d-glucaric acid (GA), in deuterium oxide was analyzed by NMR, based on J-resolved conformation analysis using proton–proton (3JHH) and proton–carbon (2JCH and 3JCH) coupling constants, as well as nuclear overhauser effect spectroscopy. It was suggested that there were three dominant conformers of GA in equilibrium with each other, including conformer (1 (H2H3:gauche, H3H4:anti, and H4H5:gauche), conformer 2 (H2H3:gauche, H3H4:anti, and H4H5:anti), and conformer 3 (H2H3:gauche, H3H4:gauche and H4H5:anti). Conformational structures of GA in solution were ‘bent’ rather than being fully extended.

  36. Special issue research articles

    1. Selective diffusion spectroscopy using excitation sculpting

      Peter W.  A. Howe

      Version of Record online: 28 DEC 2015 | DOI: 10.1002/mrc.4402

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      The excitation sculpting pulse sequence provides a robust, reproducible and sensitive method for measuring the diffusion coefficients of minor components in complex mixtures.

  37. Reviews

    1. Characterization of fast-tumbling isotropic bicelles by PFG diffusion NMR

      Jobst Liebau, Weihua Ye and Lena Mäler

      Version of Record online: 14 DEC 2015 | DOI: 10.1002/mrc.4399

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      Small, isotropic bicelles are suitable for solution-state NMR and contain a lipid bilayer and the lipid composition is flexible. Diffusion coefficients can be measured by pulsed-field gradient NMR methods and can be used to assess bicelle size and morphology. Also, association of molecules to bicelles can be assessed by this method.

  38. Research articles

    1. 1H-NMR relaxometric studies of interaction between apoptosis specific MRI paramagnetic contrast agents and micellar models of apoptotic cells

      Aurore Van Koninckxloo, Céline Henoumont, Sophie Laurent, Robert N. Muller and Luce Vander Elst

      Version of Record online: 9 DEC 2015 | DOI: 10.1002/mrc.4397

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      Two specific hexapeptides targeting apoptosis are grafted to contrast agents (CA). We use micelles as model of apoptotic cells to investigate in vitro the interaction between grafted peptides and apoptotic cells. They are mimicking by 1,2-dipalmitoyl-sn-glycero-3-phospho-l-serine micelles and healthy cells by1,2-dipalmitoyl-sn-glycero-3-phosphocholine micelles (negative control). A ‘hump’ at high field on nuclear magnetic relaxation dispersion profiles reveals a potential interaction between micelles mimicking apoptotic cells and Gd-complexes as confirmed by transverse relaxivities measured at 60 MHz.

  39. Special issue research articles

    1. NMR characterization of novel pyranoanthocyanins derived from the pulp of Panax quinquefolius L. (North American ginseng)

      Mark H. Nabuurs, Jason L. McCallum, Daniel C. Brown and Christopher W. Kirby

      Version of Record online: 5 NOV 2015 | DOI: 10.1002/mrc.4366

      Thumbnail image of graphical abstract

      Three major pigments were determined to be present in the berry pulp of Panax quinquefolius L. They were pelargonidin 3-O-lathyroside along with two novel pyranoanthocyanins with the same disaccharide attached at the 3-O position. In the tradition of naming novel anthocyanin aglycones based on botanical origin, the new pyranoanthocyanin aglycones have been given the common names Panaxidin A (pelaragonidin-4-vinylcatechol) and Panaxidin B (pelargonidin-4-vinylphenol).

  40. Special issue historical

  41. Special issue research articles

    1. Improving the performance of J-modulated ADEQUATE experiments through homonuclear decoupling and non-uniform sampling

      Josep Saurí, Teodor Parella, R. Thomas Williamson and Gary E. Martin

      Version of Record online: 31 AUG 2015 | DOI: 10.1002/mrc.4322

      Thumbnail image of graphical abstract

      Enhancement of J-modulated ADEQUATE experiments through homodecoupling (HD) and non-uniform sampling (NUS) are described. Sensitivity (s/n) is enhanced by homodecoupling and resolution in the F1 frequency domain is enhanced by the application of NUS. Improvements in the experiments can be exploited to save time or conversely to achieve higher s/n in the same time. The modifications facilitated the measurement of nJCC couplings of < 3 Hz with the J-modulated 1,n-HD-ADEQUATE sequence.

    2. NMR studies of dilithiostyrenes: aggregation, NMR parameters, and DFT calculations for (E)-1-Lithio-2-(o-lithiophenyl)-1-trimethylsilylethen

      Bernd Böhler, Harald Günther, Kerstin Reider, Adalbert Maercker, Dennis Gerbig and Heike Hausmann

      Version of Record online: 6 AUG 2015 | DOI: 10.1002/mrc.4298

      Thumbnail image of graphical abstract

      The NMR properties, the structure, and the dynamic behavior of a trimethylsilyl-substituted dilithiostyrene have been determined in solution.

    3. Complete 1H NMR assignment of cedranolides

      Nury Perez-Hernandez, Barbara Gordillo-Roman, Daniel Arrieta-Baez, Carlos M. Cerda-Garcia-Rojas and Pedro Joseph-Nathan

      Version of Record online: 1 JUL 2015 | DOI: 10.1002/mrc.4246

      Thumbnail image of graphical abstract

      The complete 1H NMR assignment of ten members of the cedranolide family, including economically important α-cedrene and cedrol, is described using the iterative full spin analysis included in the PERCH NMR software (PERCH Solutions Ltd., Kuopio, Finland). The coupling constants were correlated with the conformational preferences of the cedranolides calculated using the complete basis set method.


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