Recent Advances in Nuclear Shielding Calculations

Dios, Angel C. de; Jameson, Cynthia J.

doi:10.1016/b978-0-12-397020-6.00001-5

Cited by 22 publications

(22 citation statements)

References 365 publications

(409 reference statements)

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“…[1][2][3][4][5][6][7][8][9][10][11][12] Isotope shifts 13 and temperature dependence of NMR parameters are experimental manifestations of such dynamical averaging effects. Traditionally, quantum-chemical simulations of NMR parameters have been common for "isolated" molecules, such as those in gases or solutions.…”

Section: Introductionmentioning

confidence: 99%

Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations

Dračínský

Bouř

Hodgkinson

2016

J. Chem. Theory Comput.

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Citation for published item:hr § ¡ %nsk¡ yD w rtin nd fourD etr nd rodgkinsonD ul @PHITA 9 emper ture dependen e of xw p r meters l ul ted from p th integr l mole ul r dyn mi s simul tionsF9D tourn l of hemi l theory nd omput tionFD IP @QAF ppF WTVEWUQF Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The influence of temperature on NMR chemical shifts and quadrupolar couplings in model molecular organic solids is explored using path integral molecular dynamics (PIMD) and density functional theory (DFT) calculations of shielding and electric field gradient (EFG) tensors. An approach based on convoluting calculated shielding or EFG tensor components with probability distributions of selected bond distances and valence angles obtained from DFT-PIMD simulations at several temperatures is used to calculate the temperature effects. The probability distributions obtained from the quantum PIMD simulations, which includes nuclear quantum effects, are significantly broader and less temperature dependent than those obtained with 2 conventional DFT molecular dynamics or with 1D scans through potential energy surface.Predicted NMR observables for the model systems were in excellent agreement with experiment.

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Section: Introductionmentioning

confidence: 99%

Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations

Dračínský

Bouř

Hodgkinson

2016

J. Chem. Theory Comput.

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“…They may also be based on the electronic wave function or on electron density obtained through the DFT formalism. [23][24][25] A third option is the polarization propagator that must be considered though it is not formally based on similar grounds.…”

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confidence: 99%

Relativistic and Electron-Correlation Effects on the Nuclear Magnetic Resonance Shieldings of Molecules Containing Tin and Lead Atoms

Maldonado

Aucar

2014

J. Phys. Chem. A

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The reference values for NMR magnetic shieldings, σ ref , are of highest importance when theoretical analysis of chemical shifts are envisaged. The fact that the non relativistically valid relationship among spin-rotation constants and magnetic shieldings is not any longer valid for heavy atoms makes that the search for σ ref for such atoms needs new strategies to follow.We present here results of σ ref that were obtained applying an own simple procedure which mix accurate experimental chemical shifts (δ) and theoretical magnetic shieldings (σ). We calculated σ(Sn) and σ(Pb) in a family of heavy-halogen containing molecules.We found out that σ ref (Sn; Sn(CH 3 ) 4 ) in gas phase should be close to 3864.11 ± We studied tin and lead shieldings of the XY 4−n Z n (X = Sn, Pb; Y , Z = H, F, Cl, Br, I) and PbH 4−n I n (n = 0, 1, 2, 3, 4) family of compounds with four-component functionals as implemented in the DIRAC code. For these systems results of calculations with RelPPA-RPA are more reliable than the DFT ones. We argue on why those DFT functionals must be modified in order to obtain more accurate results of NMR magnetic shieldings within the relativistic regime: first, there is a dependence among both, electron correlation and relativistic effects that should be introduced in some way in the functionals; and second, the DIRAC code uses standard non-relativistic functionals and the functionals B3LYP and PBE0 were parameterized only with data taken from light elements. It can explain why they are not able to properly introduce relativistic effects on nuclear magnetic shieldings.We finally show that in the analysis of magnetic shieldings for the family of compounds mentioned above, one must consider the newest and so called heavy-atom effect on vicinal heavy atoms, HAVHA. Such effects are among the most important relativistic effects in these kind of compounds.

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“…[1][2] Isotope shifts 3 and the temperature dependence of NMR parameters are experimental manifestations of such dynamic averaging effects. In the last decade, the gauge-including projector-augmented wave (GIPAW) procedure has been developed for the prediction of the magnetic resonance parameters in solids.…”

Section: Introductionmentioning

confidence: 99%

“…In solutions, where the configurations of neighbours change dynamically, the intermolecular contributions to shielding also change with changing configurations. 2,7 Therefore, dynamic averaging needs to be taken into account, even when there are no significant strong intermolecular interactions such as hydrogen bonding.…”

Section: Introductionmentioning

confidence: 99%

A molecular dynamics study of the effects of fast molecular motions on solid-state NMR parameters

Dračínský

Hodgkinson

2013

CrystEngComm

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Citation for published item:hr § ¡ %nsk¡ yD wrtin nd rodgkinsonD ul @PHIQA 9e moleulr dynmis study of the e'ets of fst moleulr motions on solidEstte xw prmetersF9D grystinggommFD IS @RQAF ppF VUHSEVUIPF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHQWGQeRHTIP Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe influence of fast molecular motions on NMR parameters in molecular organic solids is explored on a set of amino acids and nucleic acid bases. A combination of DFT molecular dynamics and calculations of shielding and electric field gradient (EFG) tensors reveals the impact of vibrational motions on isotropic chemical shifts, chemical shift anisotropies (CSAs) and quadrupolar interactions. We demonstrate that molecular motion has a significant effect on average molecular structures, and that neglecting the effects of motion on crystal structures derived by diffraction methods may lead to significant errors of calculated isotropic chemical shifts. Re-orientation of the NMR tensors by molecular motion reduces the magnitudes of the NMR anisotropies, and inclusion of molecular dynamics can significantly improve the agreement between calculated quadrupolar couplings and experimental values.

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Recent Advances in Nuclear Shielding Calculations

Cited by 22 publications

References 365 publications

Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations

Temperature Dependence of NMR Parameters Calculated from Path Integral Molecular Dynamics Simulations

Relativistic and Electron-Correlation Effects on the Nuclear Magnetic Resonance Shieldings of Molecules Containing Tin and Lead Atoms

A molecular dynamics study of the effects of fast molecular motions on solid-state NMR parameters

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