NMR chemical shifts in MNDO approximation: Parameters and results for H, C, N, and O

Patchkovskii, Serguei; Thiel, Walter

doi:10.1002/(sici)1096-987x(199909)20:12<1220::aid-jcc3>3.0.co;2-#

Cited by 32 publications

(73 citation statements)

References 181 publications

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“…In accordance with the given recommendations [31] all present NICS results have been obtained with parameterization B and with inclusion of the three-center terms. The computational procedures have been fully documented [31] and used as implemented in the MNDO97 program [33].…”

Section: Methodssupporting

confidence: 70%

“…The original GIAO-MNDO paper provides two different parameterizations (methods A and B, respectively) and an analysis of the influence of the three-center terms on the computed shifts [31]. In accordance with the given recommendations [31] all present NICS results have been obtained with parameterization B and with inclusion of the three-center terms.…”

Section: Methodsmentioning

confidence: 63%

“…We have recently implemented [31] the evaluation of the NMR chemical shift tensor at the semiempirical MNDO level [32] using gauge-including atomic orbitals (GIAO) and analytic derivative theory. A special MNDO parameterization has been carried out for the elements H, C, N, and O [31] to reproduce the experimental NMR chemical shifts for a large number of (mostly organic) molecules and ions.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…A special MNDO parameterization has been carried out for the elements H, C, N, and O [31] to reproduce the experimental NMR chemical shifts for a large number of (mostly organic) molecules and ions. The final rms deviations from experiment are less than 5% of the total chemical shift range for each element [31]. In the present paper we apply this GIAO-MNDO approach to compute NICS values for a wide range of organic molecules, in order to assess its performance in this area through comparison with published ab initio and density functional NICS results.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Nucleus-Independent Chemical Shifts from Semiempirical Calculations

Patchkovskii

Thiel

2000

J Mol Model

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A recently developed special MNDO parameterization for NMR chemical shifts is used to compute the nucleus-independent chemical shifts (NICS) for a wide range of organic molecules, including [n]annulenes, polycyclic hydrocarbons, heterocycles, cage molecules, fullerenes, and pericyclic transition states. The results are compared with published NICS data from ab initio and density functional calculations. In general, there is reasonable agreement. The semiempirical NICS values tend to be smaller in absolute value than their ab initio counterparts, but they often show similar trends. The aromatic or antiaromatic character of a given system can normally be assigned correctly on the basis of the MNDO NICS values

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Section: Methodssupporting

confidence: 70%

Section: Methodsmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Nucleus-Independent Chemical Shifts from Semiempirical Calculations

Patchkovskii

Thiel

2000

J Mol Model

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The effect of motional averaging on the calculation of NMR-derived structural properties

et al. 1999

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The effect of motional averaging when relating structural properties inferred from nuclear magnetic resonance (NMR) experiments to molecular dynamics simulations of peptides is considered. In particular, the effect of changing populations of conformations, the extent of sampling, and the sampling frequency on the estimation of nuclear Overhauser effect (NOE) inter-proton distances, vicinal 3 J-coupling constants, and chemical shifts are investigated. The analysis is based on 50-ns simulations of a ␤-heptapeptide in methanol at 298 K, 340 K, 350 K, and 360 K. This peptide undergoes reversible folding and samples a significant proportion of the available conformational space during the simulations, with at 298 K being predominantly folded and at 360 K being predominantly unfolded. The work highlights the fact that when motional averaging is included, NMR data has only limited capacity to distinguish between a single fully folded peptide conformation and various mixtures of folded and unfolded conformations. Proteins 1999;36:542-555.1999 Wiley-Liss, Inc.

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The effect of motional averaging on the calculation of NMR‐derived structural properties

et al. 1999

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The effect of motional averaging when relating structural properties inferred from nuclear magnetic resonance (NMR) experiments to molecular dynamics simulations of peptides is considered. In particular, the effect of changing populations of conformations, the extent of sampling, and the sampling frequency on the estimation of nuclear Overhauser effect (NOE) inter-proton distances, vicinal (3)J-coupling constants, and chemical shifts are investigated. The analysis is based on 50-ns simulations of a beta-heptapeptide in methanol at 298 K, 340 K, 350 K, and 360 K. This peptide undergoes reversible folding and samples a significant proportion of the available conformational space during the simulations, with at 298 K being predominantly folded and at 360 K being predominantly unfolded. The work highlights the fact that when motional averaging is included, NMR data has only limited capacity to distinguish between a single fully folded peptide conformation and various mixtures of folded and unfolded conformations. Proteins 1999;36:542-555.

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NMR chemical shifts in MNDO approximation: Parameters and results for H, C, N, and O

Cited by 32 publications

References 181 publications

Nucleus-Independent Chemical Shifts from Semiempirical Calculations

Nucleus-Independent Chemical Shifts from Semiempirical Calculations

The effect of motional averaging on the calculation of NMR-derived structural properties

The effect of motional averaging on the calculation of NMR‐derived structural properties

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