13C,1H spin–spin coupling. X—Norbornane: A reinvestigation of the karplus curve for3J(13C,1H)

Aydın, Rafet; Günther, Harald

doi:10.1002/mrc.1260280513

Cited by 90 publications

(55 citation statements)

References 90 publications

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“…• , the 3 J(C 1 ,H 3 ) coupling is only 10.0 Hz, which is close to the value predicted by the Karplustype relationship given by Aydin and Günther, 23 i.e., 9.4 Hz, for a 180…”

supporting

confidence: 69%

NMR ³J(C₁,H₃) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

2001

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ABSTRACT:In this work a rationalization of the very large substituent effects on 3 J(C 1 ,H 3 ) couplings in 1-X-bicyclo[1.1.1]pentanes is presented. The Fermi contact contribution to such couplings was calculated in a series of 13 X-derivatives within the DFT-B3LYP framework using the finite perturbation theory. Core electrons for atoms beyond the Second Row were taken into account using effective core potentials. Calculated couplings are in very good agreement with experimental values. The role played by hyperconjugative interactions involving bonds or antibonds belonging to the coupling pathway are studied using the NBO approach. Heavy atom contribution to substituent effects on 3 J(C 1 ,H 3 ) couplings was estimated as small. This contrasts notably with trends observed in the corresponding 13 C substituent chemical shifts, SCSs. The latter were estimated comparing for X = Cl, Br, I, SnMe 3 , calculated SCSs with their experimental values. Such estimations are in line with explicit calculations of the spin-orbit contribution reported in the literature for smaller compounds.

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“…• , the 3 J(C 1 ,H 3 ) coupling is only 10.0 Hz, which is close to the value predicted by the Karplustype relationship given by Aydin and Günther, 23 i.e., 9.4 Hz, for a 180…”

supporting

confidence: 69%

NMR ³J(C₁,H₃) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

2001

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“…Obviously this was the result of the accumulation of uncertainties in the course of structural and spectral calculations. Most probably the Karplus equation used 11 did not afford accurate 3 J CH values for the C-S-C-H fragments. Thus, the additional seven parameters taken into consideration did not permit the evaluation of the population of the theoretically possible number of conformers.…”

Section: )H(6c) C(8)h(6t) C(6)h(8t) C(13)h(9c) C(13)h(9t) C(11)h(9c) mentioning

confidence: 97%

“…It is worth noting the excellent coincidence of the experimental and calculated couplings, which is probably limited only by the accuracy of molecular modelling and the current approximation of the Karplus equations 11,12 (multiple R = 0.999, RMS = 0.25, see Table 8). …”

Section: B-dmentioning

confidence: 98%

“…10,11 We performed a partial analysis of proton-coupled 13 C NMR spectrum for solution of 1 in C 6 D 6 , which provided us with experimental values of vicinal couplings of the methyl carbon atom 3 J C(13)H(9c) and 3 J C(13)H(9t) ( Table 7 and Table 8). These parameters were also calculated for all 28 individual conformers using the Karplus equation 11 , and then we estimated C-H coupling for the A, B and C macroconformers by averaging with the Boltzmann weight factor within each group. Hence we obtained four vicinal couplings to test the three-conformer equilibrium model for macrocycle 1.…”

Section: B-dmentioning

confidence: 99%

See 1 more Smart Citation

Conformational analysis of a 12‐membered crown dithioether in the solid state and in solution

Samoshin

Troyansky

Demchuk

et al. 1998

J. Phys. Org. Chem.

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The solid-state molecular structure and the conformational behaviour in solution of the 12-membered crown dithioether 8-methyl-1,4-dioxa-7,10-dithiacyclododecane-5,12-dione were studied by x-ray crystallography, 1 H and 13 C NMR spectroscopy and molecular mechanics. The conformational rigidity of some constituent structural fragments allowed a detailed analysis of the structure and distribution of the conformers. A protocol for studies of multiconformational equilibrium was developed by means of the combined use of structure calculations and dynamic NMR measurements.

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“…An extension of this methodology to more flexible molecules will be one of the further topics of our research. [30,31] ) for the conformers 1 a and 2 a and ensembles of conformers. [a] Ensembles of conformers (1 a and 1 b, equally weighted or weighted according to their energy difference) for the both diastereoisomers of 1 (MP2 structures used).…”

mentioning

confidence: 99%

Determination of the Relative Configuration of a Five-Membered Lactone from Residual Dipolar Couplings

Thiele

Marx

Berger

et al. 2006

Angew. Chem. Int. Ed.

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¹³C,¹H spin–spin coupling. X—Norbornane: A reinvestigation of the karplus curve for³J(¹³C,¹H)

Cited by 90 publications

References 90 publications

NMR ³J(C₁,H₃) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

NMR ³J(C₁,H₃) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

Conformational analysis of a 12‐membered crown dithioether in the solid state and in solution

Determination of the Relative Configuration of a Five-Membered Lactone from Residual Dipolar Couplings

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13C,1H spin–spin coupling. X—Norbornane: A reinvestigation of the karplus curve for3J(13C,1H)

Cited by 90 publications

References 90 publications

NMR 3J(C1,H3) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

NMR 3J(C1,H3) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

Conformational analysis of a 12‐membered crown dithioether in the solid state and in solution

Determination of the Relative Configuration of a Five-Membered Lactone from Residual Dipolar Couplings

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Product

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¹³C,¹H spin–spin coupling. X—Norbornane: A reinvestigation of the karplus curve for³J(¹³C,¹H)

NMR ³J(C₁,H₃) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects

NMR ³J(C₁,H₃) couplings in 1‐X‐bicyclo[1.1.1]pentanes. FPT–DFT and NBO studies of hyperconjugative interactions and heavy atom substituent effects