The Experts below are selected from a list of 36 Experts worldwide ranked by ideXlab platform
J. C. Lauer - One of the best experts on this subject based on the ideXlab platform.
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Characterization of hydrogenated derivatives of methyl- and dimethyldicyclopentadiene isomers by gas chromatography–mass spectrometry and carbon-13 nuclear magnetic resonance spectroscopy
Analyst, 2018Co-Authors: F. Schmit-quilès, Daniel Nicole, J. C. LauerAbstract:The identification of the di- and tetrahydrogenated derivatives of methyl- and dimethyldicyclopentadiene isomers has been performed directly in the hydrogenated mixtures, by comparing the results from the gas chromatography–mass spectrometric mass balance with those from quantitative 13C nuclear magnetic resonance spectra. The assignment of the carbons of these isomers has been realized by analysing data from J-Modulated Spin-Echo sequences and by applying semi-empirical rules for the influence of the methyl groups on the carbon chemical shifts in cyclopentane and norbornane ring systems.
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Characterization of methyl derivatives of cyclopentadiene monomer and dimer by 13C NMR spectroscopy
Magnetic Resonance in Chemistry, 1991Co-Authors: T. Laurens, Daniel Nicole, J. C. Lauer, Patrice Rubini, Marek Matlengiewicz, N. HenzelAbstract:The assignment of the carbons of different isomers of methylcyclopentadiene monomers (Me-CPD) and dimers (diMe-DCPD) has been performed directly in a mixture, without previous separation of these products, by analysing data from quantitative 13C NMR spectra of the mixtures and applying a J-Modulated spin–echo sequence. Semi-empirical rules for the influence of methyl groups on the chemical shifts of carbons in pentenic and norbornyl ring systems have been formulated and utilized to assign the absorptions. The same method can then be applied to the carbon assignments in cyclopentadiene–methylcyclopentadiene codimers (Me-CPD), and it is possible to develop additivity rules and predict chemical shifts for diMe-DCPD based on the chemical shifts for the carbons of these codimers.
Daniel Nicole - One of the best experts on this subject based on the ideXlab platform.
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Characterization of hydrogenated derivatives of methyl- and dimethyldicyclopentadiene isomers by gas chromatography–mass spectrometry and carbon-13 nuclear magnetic resonance spectroscopy
Analyst, 2018Co-Authors: F. Schmit-quilès, Daniel Nicole, J. C. LauerAbstract:The identification of the di- and tetrahydrogenated derivatives of methyl- and dimethyldicyclopentadiene isomers has been performed directly in the hydrogenated mixtures, by comparing the results from the gas chromatography–mass spectrometric mass balance with those from quantitative 13C nuclear magnetic resonance spectra. The assignment of the carbons of these isomers has been realized by analysing data from J-Modulated Spin-Echo sequences and by applying semi-empirical rules for the influence of the methyl groups on the carbon chemical shifts in cyclopentane and norbornane ring systems.
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Characterization of methyl derivatives of cyclopentadiene monomer and dimer by 13C NMR spectroscopy
Magnetic Resonance in Chemistry, 1991Co-Authors: T. Laurens, Daniel Nicole, J. C. Lauer, Patrice Rubini, Marek Matlengiewicz, N. HenzelAbstract:The assignment of the carbons of different isomers of methylcyclopentadiene monomers (Me-CPD) and dimers (diMe-DCPD) has been performed directly in a mixture, without previous separation of these products, by analysing data from quantitative 13C NMR spectra of the mixtures and applying a J-Modulated spin–echo sequence. Semi-empirical rules for the influence of methyl groups on the chemical shifts of carbons in pentenic and norbornyl ring systems have been formulated and utilized to assign the absorptions. The same method can then be applied to the carbon assignments in cyclopentadiene–methylcyclopentadiene codimers (Me-CPD), and it is possible to develop additivity rules and predict chemical shifts for diMe-DCPD based on the chemical shifts for the carbons of these codimers.
F. Schmit-quilès - One of the best experts on this subject based on the ideXlab platform.
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Characterization of hydrogenated derivatives of methyl- and dimethyldicyclopentadiene isomers by gas chromatography–mass spectrometry and carbon-13 nuclear magnetic resonance spectroscopy
Analyst, 2018Co-Authors: F. Schmit-quilès, Daniel Nicole, J. C. LauerAbstract:The identification of the di- and tetrahydrogenated derivatives of methyl- and dimethyldicyclopentadiene isomers has been performed directly in the hydrogenated mixtures, by comparing the results from the gas chromatography–mass spectrometric mass balance with those from quantitative 13C nuclear magnetic resonance spectra. The assignment of the carbons of these isomers has been realized by analysing data from J-Modulated Spin-Echo sequences and by applying semi-empirical rules for the influence of the methyl groups on the carbon chemical shifts in cyclopentane and norbornane ring systems.
Peter Forgo - One of the best experts on this subject based on the ideXlab platform.
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J-Modulated ADEQUATE (JM-ADEQUATE) experiment for accurate measurement of carbon-carbon coupling constants.
Journal of Magnetic Resonance, 2003Co-Authors: Katalin E. Kövér, Peter ForgoAbstract:Abstract A new method for the accurate determination of carbon–carbon coupling constants is described. The method is based on a modified ADEQUATE experiment, where a J-Modulated Spin-Echo sequence precedes the ADEQUATE pulse scheme. The J-modulation and scaling of carbon–carbon couplings is based on simultaneous incrementation of 13C chemical shift and coupling evolution periods. The time increment for the homonuclear carbon–carbon coupling evolution can be suitably scaled with respect to the corresponding increment for the chemical shift evolution. Typically a scaling factor of 2 to 3 is employed for the measurement of one-bond coupling constants, while multiplication by a factor of 10 to 15 is applied when small long-range couplings are determined. The same pulse scheme with coupling evolution period optimized for one-bond or long-range couplings allows the determination of the corresponding carbon–carbon coupling constants. The splittings of the ADEQUATE crosspeaks in the F1 dimension yield the appropriately multiplied coupling constants.
Katalin E. Kövér - One of the best experts on this subject based on the ideXlab platform.
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J-Modulated ADEQUATE (JM-ADEQUATE) experiment for accurate measurement of carbon-carbon coupling constants.
Journal of Magnetic Resonance, 2003Co-Authors: Katalin E. Kövér, Peter ForgoAbstract:Abstract A new method for the accurate determination of carbon–carbon coupling constants is described. The method is based on a modified ADEQUATE experiment, where a J-Modulated Spin-Echo sequence precedes the ADEQUATE pulse scheme. The J-modulation and scaling of carbon–carbon couplings is based on simultaneous incrementation of 13C chemical shift and coupling evolution periods. The time increment for the homonuclear carbon–carbon coupling evolution can be suitably scaled with respect to the corresponding increment for the chemical shift evolution. Typically a scaling factor of 2 to 3 is employed for the measurement of one-bond coupling constants, while multiplication by a factor of 10 to 15 is applied when small long-range couplings are determined. The same pulse scheme with coupling evolution period optimized for one-bond or long-range couplings allows the determination of the corresponding carbon–carbon coupling constants. The splittings of the ADEQUATE crosspeaks in the F1 dimension yield the appropriately multiplied coupling constants.
