bluuebunny/crossref_metadata_2025_split huggingface dataset:
13C nuclear magnetic resonance spectroscopy of selected adenine nucleosides: Structural correlation and conformation about the glycosidic bond
Authors: Akhrem A. A. , Mikhailopulo I. A. , Abramov A. F. 
Published: May 2005

AbstractStructural correlations have been carried out from 13C chemical shifts (δ) and by analysis of 1J(CH) coupling constants, and the conformation about the glycosidic bond has been studied by means of the 3J(CH) vicinal coupling constants between C‐8 and H‐1′ of some adenine nucleosides such as adenosine (Ado), N(7)‐β‐D‐ribofuranosyladenine (N(7)‐Ado), N(9)‐ and N(7)‐β‐D‐xylofuranosyladenine (N(9)‐xylAde and N(7)‐xylAde), N(9)‐(3‐chloro‐3‐deoxy‐β‐D‐xylofuranosyl)adenine (3′‐Cl‐xylAde) and N(9)‐(2‐chloro‐2‐deoxy‐β‐D‐arabinofuranosyl)adenine (2′‐Cl‐araAde). The analysis of the influence on δ13C of the nature and configuration of the substituent in the carbohydrate fragment of the molecule has revealed two types of effects, namely, 1,2‐cis and 1,2‐trans. This approach, as well as the 3J(CH) values and the analysis of the C‐3′‐endo⇌C‐2′‐endo equilibrium of the carbohydrate fragment of nucleosides, and circular dichroism (CD) data, provides important information on the conformation about the glycosidic bond. The magnitudes of 3J(C‐4, H) are indicative of the position of attachment of the carbohydrate fragment to the heterocyclic base.
Quantitative analysis of a mixture of cresols by carbon‐13 NMR spectroscopy
Authors: Chiang Hung‐Cheh , Lin Long‐Jin 
Published: May 2005

AbstractThe suitability of 13C NMR as a technique for determining o‐, m, and p‐cresols in their mixtures was investigated. Spectra were determined in methanol, containing o‐toluidine as an internal standard, without nuclear Overhauser suppression. Ratios of peak areas of each cresol isomer to o‐toluidine were determined by means of the standard calibration method, and then mixtures of cresol isomers were prepared and quantified in varying concentrations from 8.30 to 66.84 mol% for each isomer, with an average absolute error of 0.78% for all isomers. The method described was convenient and the results were generally satisfactory.
NMR Studies of ortho and meta‐ fluorocinnamate‐α‐chymotrypsin complexes
Authors: Gerig J. T. , Halley B. A. , Loehr D. T. , Reimer J. A. 
Published: May 2005

AbstractFluorine magnetic resonance spectroscopy has been used to examine the complexes formed between o‐ and m‐fluorocinnamate ions and the enzyme α‐chymotrypsin. Study of the frequency dependence of fluorine spin‐lattice and spin‐spin relaxation rates suggests that, like the p‐isomer, both the o‐ and m‐fluorocinnamates bind equally well to monomeric, dimeric and trimeric forms of the protein. Dipole‐dipole interactions with protons of the enzyme play an important role in relaxing the protein‐bound fluorine nucleus. Various deuterated forms of the ortho isomer were used to obtain evidence suggesting that the conformation of this molecule bound to the enzyme is similar if not identical to the conformation found in free solution. NMR methods were used to estimate the rates of dissociation of the complexes and the chemical shifts of the bound fluorine atoms were determined to be substantially downfield of their positions in the absence of enzyme.
A 13C NMR study of pyridoxal‐5′‐phosphate oxime
Authors: Korpela Timo , Lundell Juhani , Mäkinen Eila 
Published: May 2005

AbstractPyridoxal‐5′‐phosphate amino‐oxy acetate oxime was titrated in water, over the pH range 4–12, and the changes followed using 13C NMR. The results were compared to those of analogous Schiff's bases presented in the literature. The chemical shifts and titration curves of the oxime were appreciably different from those of the Schiff's bases, and the differences are explained as being due to the absence of ketoenamine‐enolimine tautomerism in the oxime. The low chemical shift value and the large changes of the oxime azomethine carbon during titration, as compared to the Schiff's bases, are discussed. The high stability of the oximes in water makes them suitable as model compounds for some tautomeric forms of the Iess stable Schiff's bases.
Selenium‐77 chemical shifts of cyclodiphosphazane selenides
Authors: Keat R. , Rycroft D. S. , Thompson D. G. 
Published: May 2005

AbstractIsomeric cyclodiphosphazane selenides, R(X)P(NBu1)2P(Y)R (R=OMe or NMe2, X=Se, Y=lone pair; R=OMe or NMe2, X=Y=Se) display large differences (34–122 ppm) in 77Se chemical shift. The 77Se shifts of these and related amino derivatives are well to low field of the 77Se shifts of analogous acyclic phosphorus selenides.
Effets de Solvant Aromatique en Résonance Magnétique Protonique des Stéroïdes Hydroxylés
Authors: Genard P. 
Published: May 2005

AbstractL'hydroxylation de stéroïdes saturés tels que l'androstane et le prégnane entraîne un effet de solvant aromatique appréciable au niveau des protons des méthyles angularies 18‐H et 19‐H.Les déplacements chimiques associés à plusieurs hydroxyles ou à des hydroxyles et des cétones, sont en général approximativement additifs.
Aziridines N‐Non substituées. Détermination des Paramètres Thermodynamiques ΔG°, ΔH°, ΔS° Liés à l'Equilibre Conformationnel à partir de Mesures RMN 1H à Haut Champ
Authors: Lopez A. , Gauthier M. M. , Martino R. , Lattes A. 
Published: May 2005

AbstractBien que le phénomène d'inversion de l'azote dans les aziridines secondaires ait pu être mis en évidence par RMN 1H, seule une étude systématique à 250 MHz a permis d'étudier quantitativement la répartion des deux invertomères et ainsi, de déterminer les paramètres thermodynamiques liés à l'équilibre conformationnel. Ces paramètres ont été déterminés pour 32 composés. Dans les aziridines C‐phénylées, une variation de l'encombrement du groupement aromatique en fonction des autres substituants du cycle aziridine peut être mis en évidence. Ces observations prouvent l'existence d'un phénomène de conjugaison entre système aromatique et petit cycle. phénomène préalablement mis en évidence par effet Faraday.
1H NMR studies of intramolecular hydrogen bonding in N‐(pyridyl)amides of 6‐methylpicolinic acid N‐oxide
Authors: Brzezinski Bogumil 
Published: May 2005

AbstractThe 1H NMR spectra of seven N‐(pyridyl)amides of 6‐methylpicolinic acid N‐oxide in chloroform were obtained. The influence on the chemical shifts of the NH protons of temperature, concentration and the CH3 substituent in the pyridine ring was studied. The NH protons were found to be shifted to low fields (∼14 ppm) owing to the formation of strong intramolecular hydrogen bonding. The influence of the pyridine ring on the chemical shift of the NH proton is comparable with the inductive effect of the p‐nitrophenyl group. The hindered rotation around the N‐pyridyl bond of N‐(α‐pyridyl)amides of 6‐methylpicolinic acid in solution is discussed.
A 1H NMR study of the tropylium ion, partially oriented in a lyotropic solvent
Authors: Diehl P. , Jokisaari J. , Dombi G. 
Published: May 2005

AbstractThe 1H NMR spectrum of tropylium fluoroborate dissolved and oriented in a lyotropic decyl sulphate phase has been recorded and analysed. Direct as well as indirect HH coupling constants have been obtained. The vibrationally uncorrected proton skeleton structure deviates slightly from a regular heptagon. The deviations are between two and three times larger than those of benzene from a hexagon, previously observed in the same solvent.
Analyse Conformationnelle par RMN du Proton des Oxo‐2 Oxathiazannes‐1,2,3 (Sulfinamates Cycliques) Diversement Substitués en 3, 4 et 6
Authors: Tisnès P. , Maroni P. , Cazaux L. 
Published: May 2005

AbstractCette étude menée sur seize composés montre qu'en l'absence des substituants sur les carbones en 4,5 et 6, la forme chaise à groupe SO axial (CA) est la plus stble d'au moins 8,4 kJ mole−1, comme dans le cas des sulfites cycliques correspondants. Lorsqu'il y a des substituants méthyles ou tertiobutyles en 4 et 6, la conformation dépend de leur orientation par rapport au groupe SO, ainsi que de la nature du substituant sur l'atome d'azote. Pour les configurations trans, la conformation reste chaise CA anancomère, sauf lorsqu'il existe des interactions gauches importantes: pour le tert‐butyl‐3 méthyl‐4‐t‐oxo‐2‐r oxathiazanne‐1,2,3 la forte interaction gauche Me/tBu conduit à une conformation croisée d'axe‐3,6 à SO axial (CNA). Lorsqu'un des substituants en 4 et 6 est cis, la conformation du sulfinamate peut être soit chaise à SO axial (CA) si c'est un méthyle en 4, même avec un tertiobutyle en 3 qui serait alors axial, soit croisée d'axe‐1,4 à SO axial (COA) si c'est un tertiobutyle. Contrairement aux sulfites cycliques, les formes chaises à SO équatorial (CE) et croisée d'axe‐2,5 à SO isoclinal (CS, CS′) sont l'exception et ne sont rencontrées qu'au sein d'équilibres conformationnels.
Etude des Dérivés de la Vitamine B6. Conformation des Complexes de Lanthanides avec le Pyridoxal‐5′‐phosphate et la Pyridoxamine‐5′‐phosphate en Phase Aqueuse à pD = 1,3
Authors: Asso M. , Asso L. , Mossoyan J. , Benlian D. 
Published: May 2005

AbstractUne méthode de traitement de données de déplacements paramagnétiques des résonances 1H et 13C permet d'établir l'analyse conformationnelle de molécules flexibles coordinées aux cations de lanthanides. Les exemples du pyridoxal 5′‐phosphate (PLP) et de la pyridoxamine 5′‐phosphate (PMP) en solution aqueuse, à pD = 1,3, ont été traités. Dans les deux cas, la rotation autour de PO‐5′, est une rotation empéchée avec une distribution gaussienne autour de la valeur la plus probable. Les valeurs des angles et des distances entre la cation de terre rare et les noyaux du ligand sont déterminées.
RMN du 13C de Composés Méthylés Soufrés
Authors: Dauphin G. , Cuer A. 
Published: May 2005

AbstractUne étude par spectroscopie 13C d'une série de composés méthylés soufrés est réalisée. Les effets des fonctions soufrées –SH, –SMe, –SSMe, –SSEt, –SSMe, –SC(O)Me, –SC(S)Me sur le déplacement chimique du carbone méthylique sont examinés. Les déplacements chimuques 13C d'une série de thio et dithioesters méthyliques aliphatiques sont comparés à ceux des esters correspondants et reliés aux propriétés chimiques.
Etude en Résonance Magnétique Nucléaire du Carbone‐13 de Quelques Aminopyrazoles. Sur le Problème de la Détermination des Constantes d'Equilibre Tautomère
Authors: Gonzalez Emmanuel , Faure Robert , Vincent Emile‐Jean , Espada Modesta , Elguero José 
Published: May 2005

AbstractLes déplacements chimiques du 13C de trente‐deux pyrazoles ont été mesurés dans le diméthylsulfoxyde hexadeutérié et l'hexaméthylphosphorotriamide. Nous avons déterminé l'influence respective des différents substituants par régression multilinéaire (substitutions par un méthyle et un amino sur les carbones de l'hétérocycle, et par un méthyle, un n‐butyle et un phényle sur l'azote). Le problème de la détermination des constantes d'équilibre tautomère, à partir des résultats de la RMN du 13C est discuté et illustré avec le cas des amino‐3(5) pyrazoles.
Nuclear magnetic resonance of 1,4‐benzodiazepines. II Stereochemistry of 1,3‐dihydro‐2H‐1,4‐benzodiazepin‐2‐ones by lanthanide shift reagents
Authors: Romeo G. , Aversa M. C. , Giannetto P. , Vigorita M. G. , Ficarra P. 
Published: May 2005

AbstractThe sterochemistry of some 1,3‐dihydro‐2H‐1,4‐benxodiazepin‐2‐ones, employed as psychotherapeutic agents, is deduced by proton magnetic resonance using the paramagnetic shift reagent Eu(fod)3. the lanthanide induced shifts are computer simulated on the basis of the geometric parameters of the protons in different model structures, having intermediate conformations between a cycloheptadiene‐ and a cyclohepatatriene‐like system. N‐Desmethyldiazepam shows a conformational equilibrium between two pseudoboat forms, while the 1‐alkyl substituted derivatives exist, at room temperature, in olny one boat cycloheptatriene‐like conformation.
15N NMR spectroscopy 12:—steric effects in diastereomeric oligopeptides of alanine, phenylalanine and valine
Authors: Kricheldorf Hans R. , Hull William E. 
Published: May 2005

AbstractEight pairs of diastereomeric di‐, tri‐, and tetrapeptides were prepared from alamine, phenylalanine, valine and glycine. Their natural abundance 15N NMR spectra were measured in a 1:1 mixture of acetone/dimethyl sulphoxide and in all eight cases the diastereomers could be distinguished without the aid of shift reagents. The shift difference between the signals of diastereomers is dependent on the nature of the amino acid and on the solvent.
1H NMR studies of phenylazo‐alkenes. Proton shielding increment values for the s‐trans‐(E)‐phenylazo substituent
Authors: Schantl Joachim 
Published: May 2005

AbstractThe additive proton shielding increments for the s‐trans‐(E)‐phenylazo substituent have been evaluated from the 1H NMR spectra of a number of phenylazo‐alkenes. Deviations from additivity are indicative of a different stereochemistry of the azo‐ene system.
Calculation of some 13C chemical shifts for compounds containing cumulative double bonds. The allene, ketenimine and carbodiimide series
Authors: Collier C. , Webb G. A. 
Published: May 2005

AbstractCalculations based on Pople's independent electron model, with CNDO/S and INDO/S parameterizations, are reported for some ketenimines and carbodiimides. The unusually large shielding of the central carbon uncleus is accounted for by means of the various electronic transitions which contribute to the paramagnetic shielding term. Changes in carbon charge densities tend to predict a chemical shift trend opposite to that observed.
1H‐ und 13C‐NMR‐Untersuchungen zur Struktur N‐substituierter Tetrazole—Die Strukturen des N‐Methoxycarbonyl‐, N‐Acetyl‐ und N‐(Tri‐n‐butylstannyl)‐tetrazols sowie Substituenteneffekte auf δ13C und 1J(CH)
Authors: Könnecke Andreas , Kleinpeter Erich 
Published: May 2005

AbstractDie 1H‐ und 13C‐NMR‐Spektren einiger isomerer N‐substituierten Tetrazole wurden untersucht. Zur Unterscheidung der strukturisomeren N‐substituierten Tetrazole sind die 13C‐NMR‐Spektren besser geeignet, eine Ausnahme sind Derivate mit elektropositiven Substituenten wie SnBu3. Korrelationen von δC‐5 (invers) und 1J(C‐5,H) mit σ1 bei 1‐substituierten Tetrazolen erlaubten die Strukturzuodnung des N‐SnBu3‐ Derivates als 1‐(Tri‐n‐butylstannyl)tetrazol. Die chemische Verschiebungsdifferenz der Phenylkohlen‐stoffatome ΔC′ = δC‐3′—δC‐2′ ist kein signifikantes Struktur‐ und Konformationskriterium für N‐substituierte 5‐Phenyltetrazole; aussagekräftiger scheint ΔH′ der 1H‐NMR‐Spektren zu sein.
The alkali cation effect on the 1H NMR chemical shifts of the indenyl carbanion
Authors: Gooijer C. , Velthorst N. H. 
Published: May 2005

AbstractThe complex character of the temperature dependence of the 1H NMR chemical shifts of indenyl‐lithium and ‐sodium in dimethoxyethane is explained. It is shown that the cation causes a polarisation of the CH bonds and thus influences the proton shifts of the anion, both directly by its electric field along the bonds (the direct effect) and indirectly via its effect on the π‐electron distribution (the indirect effect). The indirect effect is inferred from 13C NMR chemical shift data. By subtracting the temperature dependent contribution of the indirect effect from the experimental 1H data, the direct effect is visualised. It appears that information on ion paris obtained by 1H and 13C NMR on the one hand and optical spectroscopy on the other hand is complementary. Apparently, aggregation of ion pairs does not seriously affect the chemical shift data.
13C‐NMR‐Spektren von Cyclopropenen und Benzocyclopropenen
Authors: Albert Karl‐Heinz , Dürr Heinz 
Published: May 2005

AbstractFür Methyl‐, Halogen‐, Ester‐ und Phenylsubstituierte Cyclopropene und für Cyclopropenon und Diphenyl‐cyclopropenon werden aus den 13C‐chemischen Verschiebungen die Substituentenparameter bestimmt. Beiden Cyclopropenonen interessierte insbesonders der Einfluß der Carbonylgruppe auf die δ‐Werte und Ladungsdichten. Die Spektren von Di‐ und Tetraphenylsubstituierten Benzocyclopropendicarbonsäure‐Derivaten und des 1H‐Cyclopropa[a]naphthalin‐1,1 ‐dimethyl‐esters wurden in Hinsicht auf die Wechselwir‐kung zwischen Cyclopropenring und anelliertem Benzolring untersucht. Die J‐Werte erweisen sich dabei alsbessere Indikatoren für Strukturänderungen als die δ‐Werte, aus denen die Substituentenparameter bestimmt werden. α‐Effekte von Substituenten lassen sich mit den Hammett'schen σ1‐Werten korrelieren.
13C‐NMR‐Spektren isomerer Diazaphenanthrene
Authors: Könnecke Andreas , Lippmann Eberhard , Mlochowski Jacek , Sliwa Wanda 
Published: May 2005

AbstractDie 13C‐chemischen Verschiebungen von elf isomeren Diazaphenanthrenen (1.5‐− 1.10‐, 2.7‐, 4.5‐− 4.7‐, und 5.6‐DAP) wurden bestimmt und iterativ durch Vergleiche mit geeigneten Modellverbindungen zugeordnet. Die erhaltenen Daten (132 Punkte) dienten zur Überprüfung der Beziehung zwischen 13C‐chemischen Verschiebungen und HMO‐Ladungsdichten. Die beste Korrelation mit einer Standardabweichung S(E) = 4.8 ppm ergaben die auf Phenanthren bezogenen chemischen Verschiebungen tertiärer Kohlenstoffatome. Die unterschiedlichen Steigungsfaktoren der Korrelationen für tertiäre und quartäre Kohlenstoffresonanzen (275–300 vs 540–550 ppm/Elektron) können auf verschiedene ΔE‐Werte für beide Typen von Kohlenstoffatomen zurückgeführt werden.
13C NMR chemical shifts of some highly‐branched acyclic compounds
Authors: Schwarz Richard M. , Rabjohn Norman 
Published: May 2005

AbstractA study has been made of the 13C chemical shifts of a number of acyclic alkanes, alkenes, nitriles and ketones which contain quaternary carbon atoms. Similar data have also been obtained for the series of compounds involved in the synthesis of triisopropylacetic acid. Substituent effects and steric factors in these highly substituted compounds are discussed in relation to the chemical shifts.
Spectroscopic studies on olefins. VII–propene and 3‐methylbutene‐1; proton NMR coupling constants as a function of solvent and temperature in relation to molecular geometry
Authors: Rummens Frans H. A. , Simon Christian , Coupry Claude , Lumbroso‐Bader Nicole 
Published: May 2005

AbstractThe proton spectra of the compounds propene (1) and 3‐methylbutene‐1 (2) have been measured in various solvents and, as neat liquids, at variable temperature. The effects of solvent and temperature on 1 are found to be small, but not negligible. The effect of temperature on the coupling constants of 2 are more pronounced, which is explained in terms of an anti‐gauche equilibrium. To obtain a consistent ΔE° value from each temperature dependent coupling constant it is necessary to correct for the non‐conformational temperature effects (obtained from 1) as well as to correct for changes in the geometry of the entire molecule, which are concurrent with a conformational transition. Such geometry changes have been calculated by a consistent force field technique, which, when coupled with INDO‐MO calculated dependencies of coupling constants on valence (and torsional) angles, provided the changes in coupling constants. The observed temperature dependence of the coupling constants of the H2CCH— moiety of 2 could be satisfactorily explained in this fashion. The difference in energy between the anti and gauche forms of 2 were determined as ΔE° = 127 ± 14 cal mol−1.
Interproton coupling constant variations in 3‐membered ring heterocycles. Separation of lone pair and inductive effects
Authors: Crist Delanson R. , Borsetti Arnold P. , Jordan Guy J. , Hammer Charles F. 
Published: May 2005

AbstractIn order to separate inductive and lone pair effects on geminal and vicinal coupling constants in a stereochemically well‐defined system, the 1H NMR spectra of phenylcyclopropane (1), N‐methyl‐2‐phenylaziridine (2), styrene oxide (3) and 1,1‐dimethyl‐2‐phenylaziridinium fluorosulfonate (4) were compared. In D2O the heterocyclic ring protons of 4 were split into an ABX pattern which gave J(cis) = 8.5, J(trans) = 7.4 and J(gem) = −4.8 Hz (signs consistent with INDOR results). From the small solvent effects on J(vic) determined from 4‐d1, it was concluded that J(gem) is −5.0 ± 1.0 Hz in methylene chloride. The absolute values for the coupling constants for 1 and 4 provide a measure of the inductive effect of the ring hetero group on J. Values of J(gem) for 2 and 3 deviated from those predicted on the basis of the above inductive effect, suggesting lone pair contributions to J(gem) of c. +5.5 Hz per lone pair. With this estimate it was possible to predict accurately the J(gem) values for 2‐t‐butyloxaziridine and 1‐t‐butyldiaziridine. The values of J(cis) and J(trans) for 2 and 3 likewise suggested a contribution of −2.5 Hz to J(cis) and −2.7 Hz to J(trans) per lone pair. The present results suggest that the major factors causing positive J(gem) values in epoxides and aziridines are increased s character to the CH bonds and lone pair effects, while the so‐called electronegativity effect actually operates in the opposite direction to decrease J(gem). Also, the unusually low J(vic) values of epoxides relative to cyclopropanes are now seen to be due more to negative lone pair contributions than to the electron withdrawing ability of oxygen.
Nitrogen‐15 nuclear magnetic resonance spectroscopy. NH proton exchange reactions of urea and substituted ureas
Authors: Yavari Issa , Roberts John D. 
Published: May 2005

AbstractProton‐coupled nitrogen‐15 NMR spectra of urea, N‐methylurea, N,‐N′‐dimethylurea, N‐methyl‐N′‐benzylurea and N‐phenylurea have been obtained at natural abundance level in neutral, basic and acidic solutions at 25°C. Base‐catalyzed NH proton exchange of the NH2 group of N‐methylurea in water was found to be 1.5 times faster than that for the ‐NH‐ group, while the corresponding acid‐catalyzed exchange is 7.5 times faster. Comparison of urea and N,‐N′‐dimethylurea in water shows urea to be 10 times faster in base but 2 times slower in acid. The ratio of the base‐catalyzed NH proton exchanges of the two ‐NH‐ groups of N‐methyl‐N′‐benzylurea in dimethyl sulfoxide is close to unity, whereas the CH3NH‐ group exchanges 4 times faster in acid. Similarly, the C6H5NH‐ group of N‐methyl‐N′‐phenylurea exchanges 50 times faster than the CH3NH‐ group in base and about 3 orders of magnitude slower in acid. The results are rationalized by consideration of steric and electronic effects.
A ‘shiftless’ relaxation reagent for metal nuclide and nitrogen‐15 magnetic resonance in aqueous solution
Authors: Gansow Otto A. , Triplett Kelly M. , Peterson Timothy T. , Botto Robert E. , Roberts John D. 
Published: May 2005

AbstractAddition of small amounts of [Gd(2 : 2 : 1)]3+ cryptate to aqueous solutions containing 111Cd2+ or formamide decreases metal nuclide or nitrogen‐15 spin‐lattice (T1) relaxation times without affecting cadmium or nitrogen chemical shifts. This cryptate is thereby demonstrated to have substantial promise for greatly decreasing the time necessary to obtain natural abundance metal nuclide or 15N NMR spectra with satisfactory signal‐to‐noise ratios for many compounds with long metal or 15N relaxation times.
Determination of the configuration of new 8,13‐diazasteroids by means of 13C NMR
Authors: Verchère Catherine , Rousselle Dominique , Viel Claude 
Published: May 2005

AbstractOne methyldecahydroisoquinoline and some octahydro‐ and decahydro‐isoquinolone derivatives were studied by 13C NMR. The configuration of these products was deduced by comparison of the experimental chemical shifts and the calculated values. Conclusions could thus be reached on the configuration of related 8,13‐diazasteroids in the 19‐norandrostane series.
Dynamic NMR study of chair–chair interconversion in N,N ‐dimethylpiperidinium iodide in aqueous solution using 13C T1p measurements
Authors: Doddrell David M. , Barron Peter F. , Field James 
Published: May 2005

Abstract13C T1ρ values measured for N,N‐dimethylpiperidinium iodide yield activation parameters (ΔH≠ and ΔG values of 43.7 and 41.6 kJ mol−1) for the chair‐chair interconversion in aqueous solution similar to those measured for 1,1‐dimethylcyclohexane. The potential of 13C T1ρ values for studying dynamic processes in aqueous solutions is illustrated.