doi: 10.1002/mrc.2251pmid: N/A
The original article to which this Erratum refers was published in Journal of Magnetic Resonance in Chemistry.
Furihata, Kazuo; Shimotakahara, Sakurako; Tashiro, Mitsuru
doi: 10.1002/mrc.2264pmid: 18537106
An efficient pulse sequence for observing a ligand binding with a receptor has been developed by incorporating the WATERGATE W5 sequence. In the conventional water ligand observed via gradient spectroscopy (WaterLOGSY) techniques, the water resonance is selectively excited using,e.g. the double‐pulsed field gradient spin–echo (DPFGSE) sequence at the initial portion of pulse sequence. In the current version, the modified WATERGATE W5 sequence is incorporated at the initial portion of the pulse sequence, and the resonance at the water frequency can be selectively reserved by the modified WATERGATE W5 sequence. The efficiency of ligand‐observed NMR screening techniques has been demonstrated using the human serum albumin (HSA)–tryptophan complex. Copyright © 2008 John Wiley & Sons, Ltd.
Keppert, M.; Rakhmatullin, A.; Simko, F.; Deschamps, Michael; Haarberg, G. M.; Bessada, C.
doi: 10.1002/mrc.2248pmid: 18524019
Phosphorus is one of the predominant impurities in the Hall–Heroult process for industrial aluminium production. The nature of the dissolved phosphorus species in the Na3AlF6AlPO4 system has been investigated by in situ high‐temperature (HT) 19F, 23Na, 27Al, 17O, and 31P NMR. The combination of these experiments enables to define the presence of PO43−, AlF52− and (AlF4OPO3)4− anions in the melt, and then the formation of AlOP bonding. Melts solidified at different cooling rates were characterised using various solid‐state NMR techniques including multiple quantum magic angle spinning (MQMAS), rotational echo double resonance (REDOR) and heteronuclear single quantum correlation (HSQC). The glass obtained by the rapid quenching of the hypereutectic melt has been carefully described in order to better understand the structure of the melt. Copyright © 2008 John Wiley & Sons, Ltd.
Pirozhenko, V. V.; Rozhenko, A. B.; Avdeenko, A. P.; Konovalova, S. A.; Santalova, A. A.
doi: 10.1002/mrc.2254pmid: 18636468
Z, E‐Isomerization has been investigated for the series of the N‐arylthio‐1,4‐benzoquinonimines using a line shape analysis in the 1H NMR spectra. Thermodynamic parameters and substituent effects have been analyzed for the isomerization process. It has been shown based on the DFT (B3LYP) calculations that the dynamic transformation for N‐arylthio‐1,4‐benzoquinonimines should be considered as a combination of the two different processes, a rotation about the NS bond and an inversion at nitrogen via the transition state with the linear C NS moiety. The free energies of activation for the isomerization (ΔG298 K) measured experimentally depend on the substitution in the quinonimine moiety and phenyl ring and can be referred either to the inversion of the nitrogen atom or to the hindered rotation about the NS bond. Copyright © 2008 John Wiley & Sons, Ltd.
Griffiths, Lee; Beeley, Howard H; Horton, Rob
doi: 10.1002/mrc.2257pmid: 18561211
A reliable method of automatically assigning one‐dimensional proton spectra is described. The method relies on the alignment of the proton spectrum with an associated heteronuclear single‐quantum coherence (HSQC) spectrum, transferring the stoichiometry and couplings to the HSQC. The HSQC spectrum is then assigned using a linear assignment procedure in which a fitness function incorporating 1H chemical shifts, 1H couplings and 13C shifts are employed. The method uniquely employs a sequential procedure in which only correlations of like stoichiometry are assigned at the same time. Copyright © 2008 John Wiley & Sons, Ltd.
Lamanna, Raffaele; Piscioneri, Ilario; Romanelli, Valeria; Sharma, Neeta
doi: 10.1002/mrc.2258pmid: 18615865
This preliminary work deals with the influence of packaging on the degradation of an Italian soft cheese studied by NMR. The NMR profiles of aqueous cheese extracts were acquired as a function of time during storage of cheese inside and outside the original package. From the NMR spectra 15 metabolites are quantified and used in a kinetic degradation model and in a multivariate algorithm in order to evaluate the changes in the metabolic composition of cheese stored under different conditions. Copyright © 2008 John Wiley & Sons, Ltd.
Cabeça, Luís Fernando; Fernandes, Sergio Antonio; de Paula, Eneida; Marsaioli, Anita Jocelyne
doi: 10.1002/mrc.2265pmid: 18642398
The topologies of proparacaine (PPC) in β‐cyclodextrin (β‐CD), PPC in egg phosphatidylcholine (EPC) liposomes and PPC in β‐CD in EPC were investigated using NMR experiments (1D ROESY and saturation transfer difference (STD)). This is the first description of the STD technique applied to PPC–EPC–β‐CD system, revealing that not only PPC was imbedded in EPC bilayer, but β‐CD was also interacting with liposome vesicles. These results are novel and were rationalized as the spontaneous formation of a ternary complex with some β‐CD molecules bound to external liposome vesicles surfaces. Copyright © 2008 John Wiley & Sons, Ltd.
Cruz, Jennifer R.; Becker, Bridget A.; Morris, Kevin F.; Larive, Cynthia K.
doi: 10.1002/mrc.2267pmid: 18615634
The interaction between doxepin, a member of the tricyclic antidepressant (TCA) class of drugs, with β‐cyclodextrin (β‐CD) was investigated using NMR. Several TCAs have been reported to form a complex with β‐CD having 1:1 stoichiometry. Previous results from UV‐visible spectroscopy, fluorescence measurements, and molecular modeling indicated that for imipramine, desipramine, and amitriptyline, the TCA aliphatic tail is included in the cyclodextrin cavity with apparently no interaction of the tricyclic ring. An alternative view of the doxepin–β‐CD complex is presented in this work using analysis of complexation‐induced chemical shifts (CICSs), the method of continuous variation (Job's analysis), and analysis of ROESY spectra. The Job's plot derived from the NMR spectral data confirms that the complex formed has 1:1 stoichiometry. The largest changes in the CICS data were observed for the aromatic protons of one of the doxepin rings, with much smaller chemical shift changes observed for the protons of the other aromatic ring and the doxepin tail. Perhaps the most significant evidence for inclusion of the doxepin tricyclic ring is the strong ROESY cross peaks between the doxepin aromatic resonances and the protons located inside the β‐CD cavity. Changes in the doxepin 1H NMR spectrum and the behavior of ROESY exchange cross peaks suggest that inclusion complex formation decreases the rate of internal motions of doxepin. Copyright © 2008 John Wiley & Sons, Ltd.
Pérez, Carlos; Suardíaz, Reynier; Ortiz, Pedro J.; Crespo‐Otero, Rachel; Bonetto, Gloria M.; Gavín, José A.; García de la Vega, José M.; Fabián, Jesús San; Contreras, Rubén H.
doi: 10.1002/mrc.2268pmid: 18566984
doi: 10.1002/mrc.2270pmid: 18613258
The assignment of singlet at 1.55 ppm and the 1:1:1 triplet at 1.519 ppm to H2O and HOD in the 400 MHz 1H NMR spectrum of CDCl3 solvent were supported by complete basis set (CBS) GIAO‐B3LYP calculated chemical shift and the CBS B3LYP estimated 2J(D,H) spin–spin coupling constant (SSCC). The CBS fitting of B3LYP/cc‐pCVxZ and B3LYP/pcJ‐n predicted SSCC values, the accurate value of 2J(D,H) = − 1.082 ± 0.030 Hz of HOD in chloroform‐d1 and the H/D isotopic shift of 0.0307(1) ppm were reported for the first time. The agreement between CBS B3LYP predicted chemical shift, spin–spin values and experiment was good. Copyright © 2008 John Wiley & Sons, Ltd.
Showing 1 to 10 of 19 Articles
A remarkable difference for 2J C 2H f coupling constant in syn and anti conformers of 5‐X‐furan‐2‐carboxaldehydes (X = CH3, Ph, NO2, Br) and a rationalization of this difference are reported. On the basis of the current knowledge of the Fermi‐contact term transmission, a rather unusual dual‐coupling pathway in the syn conformer is presented. The additional coupling pathway resembles somewhat that of the JHH in homoallylic couplings, which are transmitted by hyperconjugative interactions involving the πCC electronic system. The homoallylic coupling pathway can be labeled as σ*CH ← πCC → σ*CH. In the present case, this additional coupling pathway, using an analogous notation, can be labeled as σ* C 2C C← LP1(O1)··· LP2(OC) →σ* C CH f(σ* C 2C C) where O1 and OC stand for the ring and carbonyl O atoms, respectively. This additional coupling pathway is not activated in the anti conformers since both oxygen lone pairs do not overlap. Copyright © 2008 John Wiley & Sons, Ltd.