Induced Chemical Shift Research Articles

Lipoxygenase-mediated peroxidation of model plant extractives

Three unsaturated fatty acids, namely 9-cis,12-cis-linoleic acid, 1,2,3-tri-cis, cis-9,12-octadecadienoyl (glycerol trilinolein) and 1,2,3-tri-cis-9-octadecenoyl (triolein) were selected as models of components of plant extractives to monitor the hydroperoxygenation induced by soybean lipoxygenase (LOX), which was applied as an oxidative catalyst at room temperature. The fatty acids were monitored in colloidal dispersions in relation to their molecular changes using 1H/13C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and UV spectroscopies. The detection of the hydroperoxy group was limited due to its unstable nature. However, the reduction of protons associated with the diene groups and the substitution of hydroperoxy groups at the allylic positon in conjugated lipids were detected by the induced chemical shift of HOO-bearing 13C and 1H resonances and the oxygen absorption owing to changes in the molecule. Moreover, compared to the two other substrates, no oxygen substitution was observed in triolein, in accordance with its lower level of saturation and the absence of bis-allylic carbon. Our results are of relevance to plant fiber processing, since fatty acids are major constituents of hydrophobic deposits that cause a range of manufacturing challenges.

Purification and immobilization of lipoxygenase for production of anti-inflammatory and antibacterial agents

Three unsaturated fatty acids, namely 9-cis,12-cis-linoleic acid, 1,2,3-tri-cis, cis-9,12-octadecadienoyl (glycerol trilinolein) and 1,2,3-tri-cis-9-octadecenoyl (triolein) were selected as models of components of plant extractives to monitor the hydroperoxygenation induced by soybean lipoxygenase (LOX), which was applied as an oxidative catalyst at room temperature. The fatty acids were monitored in colloidal dispersions in relation to their molecular changes using 1H/13C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and UV spectroscopies. The detection of the hydroperoxy group was limited due to its unstable nature. However, the reduction of protons associated with the diene groups and the substitution of hydroperoxy groups at the allylic positon in conjugated lipids were detected by the induced chemical shift of HOO-bearing 13C and 1H resonances and the oxygen absorption owing to changes in the molecule. Moreover, compared to the two other substrates, no oxygen substitution was observed in triolein, in accordance with its lower level of saturation and the absence of bis-allylic carbon. Our results are of relevance to plant fiber processing, since fatty acids are major constituents of hydrophobic deposits that cause a range of manufacturing challenges.

Eu(fod)3 binding on the 1H‐NMR spectra of bis(2′‐ethylbenzoate)ethylene glycol podands

The complexing and selective binding constants of Eu(fod)(3) with bis(2'-ethylbenzoate)ethylene glycol podands having one to four oxyethylene groups was observed on their (1)H-NMR spectra at 250 MHz and 295 K in CDCl(3). The Eu(fod)(3) interaction displayed the selective binding role of oxygen on H(2)C-O-CH(2) backbones with referring the (1)H chemical shifts. The estimated equilibrium constants, K(a), of 1:1 ratio of interactions were in accordance with the Eu(fod)(3) ionic radii to bind the oxygen sites depending on the size and conformation of the esters. Esters having one or two ethyleneoxy groups gave mainly 2:2 complexes using ester sites. The minimum lanthanide-podand ester distance displayed the maximum stability so that ester with four oxyethylene groups was found to bind the Eu(fod)(3) moderately, whereas ester with three oxyethylene groups showed a large induced chemical shift due to the stability of Eu(3+) complexes with larger ethyleneoxy groups.

Pattern-Based Recognition for Determination of Enantiomeric Excess, Using Chiral Auxiliary Induced Chemical Shift Perturbation NMR

A protocol for the determination of enantiomeric excess of chiral carboxylic acid, using the subtle frequency shifts (chemical shift perturbation) in NMR spectra induced by chiral auxiliary, is described. The spectra were analyzed with two pattern recognition protocols. Principal component analysis demonstrated good enantioselective separation of the analytes, and partial least-squares was used to analyze ee values of unknown samples.

Complete Assignment and Secondary Structure of the Brazil Nut Allergen Ber e 1

In the first part of the thesis, protein-ligand interactions were investigated using the chaperone LcrH, from Yersinia as target protein. The structure of a peptide encompassing the amphipathic domain (residue 278-300) of the protein YopD from Yersinia was determined by NMR in 40% TFE. The structure of YopD278-300 is a well defined α-helix with a β-turn at the C-terminus of the helix capping the structure. This turn is crucial for the structure as peptides lacking the residues involved in the turn are unstructured. NMR relaxation indicates that the peptide is not monomeric. This is supported by intermolecular NOEs found from residue Phe280 to Ile288 and Val292 indicative of a multimeric structure with the helical structures oriented in an antiparallel manner with hydrophobic residues forming the oligomer. The interaction with the chaperone LcrH was confirmed by 1H relaxation experiments and induced chemical shift changes in the peptide Protein-ligand interactions were investigated further in the second paper using a different approach. A wide range of substances were used in screening for affinity against the chaperones PapD and FimC from uropathogenic Escherichia coli using 1H relaxation NMR experiments, surface plasmon resonance and 19F NMR. Fluorine NMR proved to be advantageous as compared to proton NMR as it is straight forward to identify binding ligands due to the well resolved 19F NMR spectra. Several compounds were found to interact with PapD and FimC through induced line-broadening and chemical shift changes for the ligands. Data corroborate well with surface plasmon resonance and proton NMR experiments. However, our results indicate the substances used in this study to have poor specificity for PapD and FimC as the induced chemical shift is minor and hardly no competitive binding is observed. Paper III and IV is an investigation of the structural features of the allergenic 2S albumin Ber e 1 from Brazil nut. Ber e 1 is a 2S albumin previously identified as the major allergen of Brazil nut. Recent studies have demonstrated that endogenous Brazil nut lipids are required for an immune response to occur in vivo. The structure was obtained from 3D heteronuclear NMR experiments followed by simulated annealing using the software ARIA. Interestingly, the common fold of the 2S albumin family, described as a right-handed super helix with the core composed of a helix bundle, is not found in Ber e 1. Instead the C-terminal region is participating in the formation of the core between helix 3, 4 and 5. The dynamic properties of Ber e 1 were investigated using 15N relaxation experiments and data was analyzed using the model-free approach. The analysis showed that a few residues in the loop between helix 2 and 3 experience decreased mobility, compared to the rest of the loop. This is consistent with NOE data as long range NOEs were found from the loop to the core region of the protein. The anchoring of this loop is a unique feature of Ber e 1, as it is not found in any other structures of 2S albumins. Chemical shift mapping of Ber e 1 upon the addition of lipid extract from Brazil nut identified 4 regions in the protein where chemical shift perturbations were detected. Interestingly, all four structural clusters align along a cleft in the structure formed by helix 1-3 on one side and helix 4-5 on the other. This cleft is big enough to encompass a lipid molecule. It is therefore tempting to speculate whether this cleft is the lipid binding epitope in Ber e 1.

The Effect of Lewis Acidity in Carbonyl Coupling Reactions.

For Abstract see ChemInform Abstract in Full Text.

Interaction between acyclic phenol--formaldehyde oligomers and quaternary ammonium ions

The interaction between acyclic phenol-formaldehyde oligomers (1) and quaternary ammonium ions (5) was investigated by 1H-NMR spectroscopy. From the induced chemical shift change of 5 in the presence of 1, the cation-pi interaction between the N(+)-(CH3)3 moiety of 5 and the pi-base of 1 occurs during the formation of the complex. Another important observation is that the OH proton signals of 1 are considerably broadened upon addition of 5, indicating that hydrogen bonding occurs between exchangeable protons of 1 and iodide anion of 5. These interactions play an important role in the binding of 5.

Synthesis and properties of calixarene analogs incorporating a thiophene unit in the macrocyclic ring

AbstractCalixarene analogs containing a thiophene unit in the macrocyclic ring were prepared by a stepwise method. The macrocycles adopt a cone‐like form as the preferred conformation in solution. The induced chemical shift change, nOe experiment, and 1H relaxation time (T1) measurement supported the fact that the macrocycle forms a complex with the N‐methylpyridinium salt. In contrast, O‐tetramethylated macrocycles and linear phenol‐formaldehyde tetramer, could not efficiently include the N‐methylpyridinium salt.

Characterization of Peptized Boehmite Systems: An27Al Nuclear Magnetic Resonance Study

Boehmite aqueous suspensions were acidified (peptized) with dilute nitric acid at room temperature to produce colloidal sol systems. These were characterized by27Al nuclear magnetic resonance spectroscopy. Two resonances in the octahedral region of the spectrum were identified. A narrow resonance was assigned to the hexaaquo ion[formula]and its monomeric hydrolyzed species, whose behavior is very similar to that of Al3+aqueous systems under self or forced hydrolysis. The other broader resonance shows a second-order quadrupolar induced chemical shift. Based on its field-dependent behavior, this peak has an isotropic chemical shift of 11.7 ppm and a quadrupolar coupling constant of 2.9 MHz. We attribute it to27Al nuclei in the colloidal particles of boehmite present in the system, with an estimated correlation time of 35 ns. When the sol–gel transition occurs, this resonance decreases in intensity, giving rise to a very broad signal at about the same frequency, tentatively assigned to larger derived structures from aggregation of the colloidal particles. This transformation was reversible at high temperature. The acidic peptization of the studied boehmite was characterized as a partial dissolution process. The amount of Al3+released to solution is nearly proportional to the total alumina content in the suspension and to the acid to aluminum molar ratio.

Degradation and absolute configurational assignment to C34-botryococcene

C 34 -Botryococcene, the major hydrocarbon constituent of the B race of Botryococcus braunii, was degraded by ozonolysis of its dihydro derivative followed by Baeyer-Villiger oxidation to γ-valerolactone, 2,5-dimethyl-hexanolactone, and 2-ethyl-2,5-dimethylhexanolactone. These three lactones were correlated with enantiomerillacy pure, synthesized materials using a progressive induced chemical shift technique with the chiral shift Eu(hfc) 3

Determination of the chiral purity of aminoalcohols by 1H NMR spectroscopy

2,2'-Dihydroxy-1,1'-binaphthyl derivatives were used as chiral shift reagents in the chiral recognition of carbocyclic aminoalcohols. The induced chemical shift differences are dependent on the ability of one or both of the OH groups of the shift reagent to coordinate with the substrate molecule for reasons of structure and stereochemistry.

ChemInform Abstract: New Chiral Shift Reagents, Optically Active 2,2′‐Dihydroxy‐1,1′‐binaphthyl and 1,6‐Di(o‐chlorophenyl)‐1,6‐diphenylhexa‐2,4‐diyne‐1,6‐diol.

ChemInformVolume 19, Issue 30 Physical Organic Chemistry ChemInform Abstract: New Chiral Shift Reagents, Optically Active 2,2′-Dihydroxy-1,1′-binaphthyl and 1,6-Di(o-chlorophenyl)-1,6-diphenylhexa-2,4-diyne-1,6-diol. F. TODA, F. TODA Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorK. MORI, K. MORI Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorJ. OKADA, J. OKADA Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorM. NODE, M. NODE Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorA. ITOH, A. ITOH Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorK. OOMINE, K. OOMINE Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorK. FUJI, K. FUJI Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this author F. TODA, F. TODA Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorK. MORI, K. MORI Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorJ. OKADA, J. OKADA Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorM. NODE, M. NODE Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorA. ITOH, A. ITOH Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorK. OOMINE, K. OOMINE Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this authorK. FUJI, K. FUJI Dep. Resour. Chem., Fac. Eng., Ehime Univ., Matsuyama, Ehime 790, JapanSearch for more papers by this author First published: July 26, 1988 https://doi.org/10.1002/chin.198830052AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume19, Issue30July 26, 1988 RelatedInformation

New Chiral Shift Reagents, Optically Active 2,2′-Dihydroxy-1,1′-binaphthyl and 1,6-Di(o-chlorophenyl)-1,6-diphenylhexa-2,4-diyne-1,6-diol

Abstract The title compounds were found to be useful as a chiral shift reagent in 1H NMR spectroscopy to determine enantiomeric purity of amines, alcohols, sulfoxides, selenoxides, phosphine oxides, phosphinates, and arsenoxides. It is also reported that the induced chemical shift difference increases when the title compound is used together with the typical chiral shift reagent, Eu(hfc)3.

A vanadium-51 nuclear magnetic resonance investigation of vanadate oxyanions in a lyotropic liquid crystalline bilayer system

The vanadate ion VO4H2− and two of its polymeric forms contained in mixed lyotropic mesophase prepared from potassium dodecanoate/n-alkyltrimethylammonium bromide in water have been investigated by 51V nuclear magnetic resonance spectroscopy. The results indicate that the tetrahedral ion interacts with the micellar surface through the hydrating water associated with this ion. The ion undergoes strong interactions with the carboxylate head group of the dodecanoate as well as with the headgroup of the alkyltrimethylammonium detergent, which of course is of opposite charge. The other two species investigated have previously been assigned by various workers to V2O74− and its cyclic dimer V4O124−. The results obtained here are not consistent with those assignments but rather with more symmetrical compounds such as the tetrahedral uncharged molecule V4O10 and a higher analogue of this, respectively. The nmr spectra from these latter species show that they undergo, at best, extremely weak interactions with the cationic surface but strong interactions with an anionic one. The behaviour of the quadrupole splittings observed is consistent with specific interactions to the carboxylate moiety. The observation of an induced chemical shift separation between vanadium resonances from the same highly symmetric species confirms that binding of this compound is very strong.

Difference in association of Tl(I) with gramicidin A and gramicidin B in trifluoroethanol determined by Tl-205 NMR

The thallium-205 chemical shift was determined as a function of temperature for the thallium(I) complexes of gramicidin A and gramicidin B in 2,2,2-trifluoroethanol. From the difference in magnitude of the induced chemical shift it was determined that gramicidin B does not bind the Tl(I) ion as well as does gramicidin A. This result may explain the lower single-channel conductance of gramicidin B relative to gramicidin A. Cabon-13 NMR studies strongly indicate that the binding site for gramicidin A and B is at teh tryptophan end of the molecule and that replacement of tryptophan residue at position 11 in gramicidin A with a phenylalanine to form gramicidin B produces a significant structural change at the tryptophan end of the molecule, but has little effect on the N-terminus.

Adrenalin autoxidation and Cu 2Zn 2 superoxide dismutase

Superoxide dismutase is known to specifically inhibit adrenalin autoxidation. In contrast noradrenalin and dihydroxyphenylalanine autoxidation reactions are inhibited by 20% only. To account for this phenomenon the formation of a specific ternary complex between oxidizing adrenalin and the copperzinc protein was deduced from extensive circular dichroism measurements. Contrary to observations with the latter catecholamines, characteristic changes of the chiroptical properties of both adrenalin in the presence of oxygen and the protein moiety of superoxide dismutase were seen. The changes of optical properties could not be observed, when the enzyme devoid of its active site or the partially reconstituted apoprotein employing either zinc or copper, reacted with adrenalin. This suggested the histidine-bridged copperzinc active site to be essential for the protein's specific reactiviy. This conclusion is supported by 360 MHz proton nuclear magnetic resonance measurements, which revealed an induced chemical shift of histidine resonance by the adrenalinsuperoxide dismutase binding. X-ray photoelectron spectrometric measurements support another aspect of the specific inhibitory action of superoxide dismutase. An unusual low nitrogen 1s-electron binding energy of adrenalin compared to other catecholamines can be explanatory for the fact that borate inhibited adrenalin cannot prevent the formation of the ternary complex with the enzyme. Therefore binding of adrenalin to the protein via the ethanol-amine side chain must be made responsible for an autoxidation pathway in the presence of superoxide dismutase.

STEREOCHEMICAL STUDIES OF COBALT(III) COMPLEXES OF SEXIDENTATE AMINOPOLYACIDS USING CARBON-13 CHEMICAL SHIFTS

Abstract Detailed assignments of the 13C NMR spectra of two series of cobalt(III) complexes have been made with the aid of methyl substitution at the terminal carbon of the diamine backbone ring and other standard techniques. One series of complexes includes ligands ethylenediaminetetraacetate ion (edta), trimethylenediaminetetraacetate ion (1,3-pdta), and 1,3-butanediaminetetraacetate ion (1,3-mpdta). The other series of complexes includes the ligands tri-ethylenetetraaminediacetate ion (ttda), 1,9-diamino-3,7-diazanonane-3,7-diacetate ion (ddda), and 1,9-diamino-4-methyl-3,7-diazanonane-3,7-diacetate ion (mddda). Spectral similarities reveal that these two types of complexes have similar bonding characteristics. Methyl substitution on the 6-membered backbone ring affects the overall complex structural parameters only slightly but the effects for a complex with a 5-membered backbone ring are obvious. The induced chemical shift changes for inductive (through-bond) and steric (through-space) perturbation of carbons caused by methyl substitution are consistent with those obtained for simple organic molecules. Comparison of carbon chemical shifts of complexes of 5-membered and 6-membered backbone ring reveals the strain effects and the results are explained partially in relation to those obtained by other spectroscopic methods. The strain effects are considered in reference to the chemical shift ranges of similar carbons in related complexes. A more strained environment makes the out-of-plane ring methylene carbon resonance more similar to that of the in-plane ring. The chemical shifts, in this case, seem to correlate with the C[sbnd]N[sbnd]C bond angles made between the methylene carbons of the side ring and of the backbone ring at the coordinated nitrogen.

ChemInform Abstract: A LONG RANGE DEUTERIUM ISOTOPE EFFECT ON A LANTHANIDE INDUCED CHEMICAL SHIFT

Chemischer InformationsdienstVolume 7, Issue 13 Physical Organic Chemistry ChemInform Abstract: A LONG RANGE DEUTERIUM ISOTOPE EFFECT ON A LANTHANIDE INDUCED CHEMICAL SHIFT C. H. DEPUY, C. H. DEPUYSearch for more papers by this authorP. C. FUENFSCHILLING, P. C. FUENFSCHILLINGSearch for more papers by this authorJ. M. OLSON, J. M. OLSONSearch for more papers by this author C. H. DEPUY, C. H. DEPUYSearch for more papers by this authorP. C. FUENFSCHILLING, P. C. FUENFSCHILLINGSearch for more papers by this authorJ. M. OLSON, J. M. OLSONSearch for more papers by this author First published: March 30, 1976 https://doi.org/10.1002/chin.197613047Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume7, Issue13March 30, 1976 RelatedInformation

The 13C Magnetic Resonance Study on the Effects of Divalent Paramagnetic Metal Acetylacetonates on Pyridine, Quinoline, and Isoquinoline. Specific Interactions with Mn(AA)2

Abstract 13C nuclear magnetic resonance studies of pyridine solutions containing paramagnetic Ni (II), Co(II), Cu(II), or Mn(II) acetylacetonate are made by observing the induced chemical shift, the line width, and the spin-lattice relaxation time due to the paramagnetism of these metals. The origin of the paramagnetic effects on the 13C spectra induced by Ni, Co, or Cu acetylacetonate is mainly the contact interaction, while the 13C spectra of the pyridine–Mn(AA)2 system can not be interpreted by the same interaction. The 13C spectra of quinoline and isoquinoline containing Mn(AA)2 are also studied; the results indicate that the predominant mechanism is the dipole-dipole interaction.

Evaluation of the Binding Constants, Bound Chemical Shifts, and Stoichiometry of Lanthanide–Substrate Complexes

A theoretical analysis of the equilibrium between a lanthanide shift reagent, L, and a substrate, S, is presented. When [Formula: see text] then a plot of [S]0vs. (1/δ) at constant [L]0 gives a straight line whose slope is [L]0ΔB and whose y-intercept is −{(1/KB) + [L]0}, where KB is the equilibrium binding constant, δ is the induced chemical shift, and ΔB is the bound chemical shift. A more general and accurate solution using a computer programme is applicable for all ratios of [L]0/[S]0. It is also shown that the conventional procedure for evaluating ΔB leads to varying values for ΔB that are generally too small, even under the most optimal conditions. Eu(DPM)34 has a KB of ca. 34.21 mol−1 with n-propylamine and KB of ca. 9.71 mol−1 with neo-pentanol. These values increase by at least 10-fold (to ≥ 1001 mol−1) for the corresponding complexes with Eu(FOD)34 shift reagent. However, the bound chemical shifts for the Eu(FOD)3 complexes are nearly the same as for the Eu(DPM)3 complexes. Finally, it is shown definitively that the association between Eu(DPM)3 and either n-propylamine or neo-pentanol has 1:1 stoichiometry; with Eu(FOD)3 a tentative assignment of 1:1 stoichiometry can be made.