Carbon-13 NMR Spectra Research Articles

Ultrahigh resolution NMR. 6. Observation of resolved carbon-13-nitrogen-15 scalar splittings in carbon-13 NMR spectra of samples of natural isotopic composition

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltrahigh resolution NMR. 6. Observation of resolved carbon-13-nitrogen-15 scalar splittings in carbon-13 NMR spectra of samples of natural isotopic compositionSteven R. Maple and Adam AllerhandCite this: J. Am. Chem. Soc. 1987, 109, 1, 56–61Publication Date (Print):January 1, 1987Publication History Published online1 May 2002Published inissue 1 January 1987https://doi.org/10.1021/ja00235a009RIGHTS & PERMISSIONSArticle Views124Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (774 KB) Get e-Alerts Get e-Alerts

ChemInform Abstract: Two-Dimensional NMR Studies of Marine Natural Products. Part 4. Isolation of the Cembranoid Diterpene Jeunicin from the Mollusc Planaxis sulcatus: Assignment of the Proton and Carbon NMR Spectra by Two-Dimensional Techniques.

Chemischer InformationsdienstVolume 17, Issue 47 Natural Products ChemInform Abstract: Two-Dimensional NMR Studies of Marine Natural Products. Part 4. Isolation of the Cembranoid Diterpene Jeunicin from the Mollusc Planaxis sulcatus: Assignment of the Proton and Carbon NMR Spectra by Two-Dimensional Techniques. R. SANDUJA, R. SANDUJASearch for more papers by this authorG. S. LINZ, G. S. LINZSearch for more papers by this authorM. ALAM, M. ALAMSearch for more papers by this authorA. J. WEINHEIMER, A. J. WEINHEIMERSearch for more papers by this authorG. E. MARTIN, G. E. MARTINSearch for more papers by this authorE. L. EZELL, E. L. EZELLSearch for more papers by this author R. SANDUJA, R. SANDUJASearch for more papers by this authorG. S. LINZ, G. S. LINZSearch for more papers by this authorM. ALAM, M. ALAMSearch for more papers by this authorA. J. WEINHEIMER, A. J. WEINHEIMERSearch for more papers by this authorG. E. MARTIN, G. E. MARTINSearch for more papers by this authorE. L. EZELL, E. L. EZELLSearch for more papers by this author First published: November 25, 1986 https://doi.org/10.1002/chin.198647349AboutPDF 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. Volume17, Issue47November 25, 1986 RelatedInformation

Assignment of monomer sequences in the carbon-13 and proton NMR spectra of several ethylene-containing Co- and terpolymers by two-dimensional NMR spectroscopy

Assignment of monomer sequences in the carbon-13 and proton NMR spectra of several ethylene-containing Co- and terpolymers by two-dimensional NMR spectroscopy

Phosphorus-31 and carbon-13 solid-state NMR of tertiary phosphine-palladium complexes bound to silica

Phosphorus-31 and carbon-13 NMR spectra with cross polarization and magic-angle spinning are used to characterize palladium-tertiary phosphine complexes and their precursors covalently bound to silica. Phosphorus-31 NMR is a good probe of complex formation and geometry, whereas /sup 13/C NMR is a good probe of ligand structure. The 36.44-MHz /sup 31/P spectrum of (identical with SiOSiCH/sub 2/CH/sub 2/PPh/sub 2/)/sub 2/PdCl/sub 2/ shows two, barely resolved peaks at about 21 and 30 ppm assigned to the trans and cis complexes, respectively. These assignments are based on the chemical shifts of model compounds in both solution and the solid state. Uncomplexed phosphine and phosphine oxide are observed when complexes are prepared from phosphinated silica but not when the complexes are preformed and then attached to silica. The palladium dichloride complexes of bis(diphenylphosphino)methane, -ethane, and -propane, all of which have an approximately square-planar configuration, were examined as solid-state models for strained cis complexes on the silica surface. As in solution, the solid-state /sup 31/P chemical shifts of these compounds occur over a range of 127 ppm while the P-Pd-P angle varies from 73 to 91/sup 0/. Hence, the /sup 31/P chemical shift is a very sensitive measure of strain in such complexes andmore » confirms that the structures in solution are similar to those in the solid state.« less

A complete proton and carbon-13 NMR analysis of fluocinonide, a fluorinated corticosteroid

This paper presents a complete analysis of the proton and carbon-13 NMR spectra of 21 -acetoxy- 6α, 9-difluoro-11β-hydroxy-16α, 17-(1-methylethylidene) bis-(oxy) pregna-1,4-diene-3,20-dione, a potent anti-inflammatory fluorosteroid. The 300 MHz proton spectrum was analyzed using a combination of the two-dimensional homonuclear chemical shift correlation (COSY) technique and one-dimensional NOE difference spectra. Exact coupling constants and chemical shifts were obtained by spectral simulation and iteration. The carbon-13 spectrum was assigned from the proton spectrum via a two-dimensional heteronuclear chemical shift experiment, and long-range fluorine-proton couplings were confirmed by a fully coupled heteronuclear COSY-type experiment.

Assignment of the 1H‐ and 13C‐NMR spectra of congested helicenes using two‐dimensional NMR methods: Phenanthro[3′,4′:3,4]phenanthro[2,1‐b]thiophene

AbstractPhenanthro[3′,4′:3,4]phenanthro[2,1‐b]thiophene has been prepared and its highly congested proton and carbon nmr spectra assigned. The nmr assignments required concerted utilization of two‐dimensional nmr techniques which included: COSY, direct and long range optimized heteronuclear chemical shift correlation and heteronuclear relayed coherence transfer.

ChemInform Abstract: Conformational Preferences of Poly(methylthio)benzenes

Abstract Examination of the carbon-13 NMR spectra and electric dipole moments of isomeric bis(methylthio)benzenes and tetrakis (methylthio)benzenes, 1,2,3- and 1,3,5-tris (methylthio)benzenes, pentakis- and hexakis-(methylthio)benzenes enabled their preferred conformations as a solute to be elucidated. In the preferred conformers, a MeS-group encompassed by two hydrogen atoms is shaped as (45°-twisted) thioanisole, a MeS-group situated near a sulphur atom is identified as 45°-twisted trans -(Me,S), and a MeS-group surrounded by two sulphur atoms is located in a plane perpendicular to the ring. The conformational problem posed by poly(methoxy)benzenes is also briefly discussed.

Proton and carbon-13 NMR spectra of a series of methyl-substituted imidazole complexes of pentaamminecobalt(III) and crystal structure of the remote isomer of [(4-methylimidazole)pentaamminecobalt(III)] trichloride dihydrate

Le compose du titre cristallise dans le systeme orthorhombique, groupe d'espace Pna2 1 et sa sturcture est affinee jusqu'a R=0,04

Carbon-13 NMR of liquid crystal solutions with magic-angle spinning. Hindered rotation in 6-(dialkylamino)fulvenes

With magic-angle spinning, the carbon-13 NMR spectra of nematic liquid crystals having positive anisotropy of the magnetic susceptibility show sharp peaks. Solutes which have carbon-13 peaks in the ‘‘window’’ regions of the solvent spectra can be conveniently studied. The hindered rotation of the dialkylamino group in 6-(dimethylamino)fulvene, 6-(diethylamino)fulvene, and 6-(N-piperidyl)fulvene in a liquid crystal solvent (E8) has been investigated by carbon-13 NMR with magic-angle spinning. The results are compared with those obtained in isotropic solutions of the same compounds in CDCl3 and CDCl3+E8. The free energy of activation (ΔG≠) of each compound in the three solvents is the same within experimental error.

Carbon CP-mass NMR and x-ray crystal structure of paramagnetic lanthanide acetates

The X-ray crystal structures of praseodymium(III) acetate monohydrate and europium(III) acetate trihydrate have been solved and cross-polarization carbon-13 NMR spectra obtained in the polycrystalline solids. The static and magic angle spinning spectra are compared with diamagnetic acetate spectra. The shifts in the paramagnetic compounds are large, permitting sample heterogeniety to be readily detected. THE CP-MASS carbon spectra are assigned by using both relaxation times and dipolar interactions as a guide.

Methods for analyzing spectroscopic line shapes. NMR solid powder patterns

A new method is described for numerically computing theoretical NMR powder patterns which achieves a many-fold increase in speed and accuracy over previous techniques. The method incorporates a simple and efficient technique for selecting the set of crystal orientations over which the spectral frequencies are calculated. The orientation selection technique is then integrated with an interpolation scheme which transfers the intensities at these frequencies to the computed spectrum. The method will be useful whenever an average over a sphere is computed numerically. The new efficiency of the method makes practical least squares fitting of theoretical spectra to experimental NMR data. The fits provide unbiased estimates of the NMR parameters and their errors. The technique is illustrated by extracting chemical shift tensors from a proton decoupled carbon-13 NMR spectrum.

Conformational preferences of poly(methylthio) benzenes

Examination of the carbon-13 NMR spectra and electric dipole moments of isomeric bis(methylthio)benzenes and tetrakis (methylthio)benzenes, 1,2,3- and 1,3,5-tris (methylthio)benzenes, pentakis- and hexakis-(methylthio)benzenes enabled their preferred conformations as a solute to be elucidated. In the preferred conformers, a MeS-group encompassed by two hydrogen atoms is shaped as (45°-twisted) thioanisole, a MeS-group situated near a sulphur atom is identified as 45°-twisted trans-(Me,S), and a MeS-group surrounded by two sulphur atoms is located in a plane perpendicular to the ring. The conformational problem posed by poly(methoxy)benzenes is also briefly discussed.

Tritium isotope effects on carbon-13 NMR chemical shifts

Deuterium isotope effects on carbon-13 NMR chemical shifts can be useful in making spectral assignments, and they are also interesting in their own right. The authors report here the first determination of tritium isotope effects on carbon-13 NMR spectra. 11 references, 2 tables.

Two‐dimensional NMR studies of marine natural products. IV. Isolation of the cembranoid diterpene jeunicin from the mollusc planaxis sulcatus: Assignment of the proton and carbon NMR spectra by two‐dimensional techniques

AbstractNumerous cembranoic diterpenes have been isolated from marine gorgonians and terrestrial plants. There have, however, been only a few reports of the isolation and identification of these interesting compounds from higher animal sources. The isolation of the oxo‐bridged cembranoid diterpene jeunicin from the mollusc Planaxis sulcatus is reported. A comparative discussion of the utility of COSY, homonuclear RELAY (relayed COSY) and proton double quantum coherence techniques is presented, the latter successfully establishing the identities of all of the proton resonances. Acquisition of a two‐dimensional proton‐carbon chemical shift correlation spectrum provided the means of unequivocally establishing 13C resonance assignments.

Isotopic multiplets in the carbon-13 NMR spectra of cobalt(III) complexes with partially deuterated coordinated amino or imino groups. Dihedral angular dependence of the three-bond isotope effects

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsotopic multiplets in the carbon-13 NMR spectra of cobalt(III) complexes with partially deuterated coordinated amino or imino groups. Dihedral angular dependence of the three-bond isotope effectsMorio. Yashiro, Shigenobu. Yano, and Sadao. YoshikawaCite this: J. Am. Chem. Soc. 1986, 108, 5, 1096–1097Publication Date (Print):March 1, 1986Publication History Published online1 May 2002Published inissue 1 March 1986https://doi.org/10.1021/ja00265a049RIGHTS & PERMISSIONSArticle Views79Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (317 KB) Get e-Alerts Get e-Alerts

Biosynthesis of porphyrins and corrins. 1. 1H and 13C NMR spectra of (hydroxymethyl)bilane and uroporphyrinogens I and III.

High-field NMR spectroscopic methods have been applied to study the reactions catalyzed by porphobilinogen (PBG) deaminase and uroporphyrinogen III (uro'gen III) cosynthase, which are the enzymes responsible for the formation of the porphyrin macrocycle. The action of these enzymes in the conversion of PBG, [2,11-13C]PBG, and [3,5-13C]PBG to uro'gens I and III has been followed by 1H and 13C NMR, and assignments are presented. The principal intermediate that accumulated was the correspondingly labeled (hydroxymethyl)bilane (HMB), the assignments for which are also presented.

Computer-assisted structure elucidation of organic compounds III: Automatic fragment generation from13C-NMR spectra

The interpretation of carbon-NMR spectra is mainly based on the comparison with suitable reference data taken from literature. The whole information contents of13C-NMR spectra cannot be utilized by manual interpretation. Therefore a network of interactive computer programs has been developed, which simulates the strategy of the spectroscopist in generating structural fragments from the spectral data. The most important knowledge source for this process is a carbon-NMR data base containing some 17,500 spectra. Structural fragments are generated automatically from this data file and assembled by a model builder to complete chemical structures using constraints derived from the spectral data. A comparison of the experimental carbon-NMR spectrum with the estimated ones allows the generation of a sorted hitlist.

Carbon-13 and proton NMR studies of post-mortem metabolism in bovine muscles

Proton and carbon-13 NMR was used to investigate post-mortem metabolism in bovine muscles at 26°C during the first 10h after slaughter. WALTZ-16 decoupling was used to eliminate the proton couplings in the 13C spectra and the ‘jump and return’ pulse sequence was used to suppress the water resonance in the 1H-NMR experiments. With carbon-13 NMR the glycogen breakdown and the lactate development could be followed. This was compared with the lactate, creatine and phosphocreatine development as measured by proton NMR. The intracellular pH was estimated from the chemical shift of the abundant dipeptide, carnosine, as measured in the 1H- and 13C-NMR spectra. These were compared with similar measurements obtained earlier using phosphorus-31 NMR. The three independently determined pH profiles were in excellent agreement with one another, as well as with results obtained with the standard iodoacetate extraction method. In the course of these studies we observed that the post-mortem metabolism in cow and heifer was slow and that it took four more hours to complete compared to bull or young bull. After 10 h the pH was 5·9 in bull and 6·1 in cow. Phosphocreatine had completely disappeared after 3·5 h in bull samples while the lactate continued to increase even after 10h. The curves obtained by carbon-13 and proton NMR for the increase in lactate during the first 10 h post mortem were very similar. Moreover, plots for the increase in the lactate level versus the intracellular pH decrease showed a linear relationship, indicating that anaerobic glycolytic activity is the main determining cause for the intracellular pH decrease. Various other parameters, such as the ratio of unsatirated to saturated fatty acid side chains and the presence of amino acids and taurine, could be measured from the in vivo carbon-13 NMR spectra. However, no gross changes occured in any of these parameters during the first 10 h post mortem.

FTIR and carbon-13 NMR spectra of chalcocarbonyl(5,10,15, 20-tetraphenylporphinato)iron(II) complexes

The room-temperature, FTIR difference spectra of the solid chalcocarbonyl(5,20,15,20-tetraphenylporphinato)iron(II) derivatives, FeTPP(CX) and FeTPP(CX)L (X = S, Se; L = pyridine, EtOH), have been recorded (in CsI disks) in order to examine the influence of the axially bound CX and L ligands on the vibrations of the metal-porphyrin ring. The 13C NMR spectra of these complexes in CD 2Cl 2 have been measured at room temperature for a similar reason. The vibrations and 13C resonances of the metal-porphyrin ring are only slightly affected by the presence of the axial ligands. The positions of the 13CX NMR resonances and the ν(CX) modes in the i.r. are dependent on the nature of L.

Effect of halothane on the natural-abundance 13C NMR spectra of excised rat brain.

Halothane increases the intensity of the 30.5- and 129-ppm resonances in 13C nuclear magnetic resonance spectra of excised rat brain, of phospholipid vesicles prepared from chloroform-methanol extract of rat brain, and of brain excised from rats anesthetized with halothane. The 13C spin-lattice relaxation times of the 30.5- and 129-ppm resonances are increased in excised brain, or phospholipid vesicles, upon addition of halothane, and they are also increased in brain excised from rats anesthetized with halothane. Excised brain and its membrane-rich subcellular fractions interact with [14C]halothane reversibly. The interaction is virtually abolished when the phospholipids are extracted from the brain. The [14C]halothane content of the brain membranes is correlated with the halothane-induced increase in the integral of the 129-ppm resonance. From this correlation and from the phospholipid content of the membranes, a halothane concentration of 3.34 mM and a partition of 0.057 mol of halothane/mol of phospholipid may be calculated in the brain of anesthetized rats.