The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts
Calculations of nuclear magnetic resonance (NMR) isotopic shifts often rest on the unverified assumption that the “vibration hole”, that is, the change of the vibration motif upon an isotopic substitution, is strongly localized around the substitution site. Using our recently developed difference-de...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-06-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/12/2915 |
| _version_ | 1827714293616869376 |
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| author | Jürgen Gräfenstein |
| author_facet | Jürgen Gräfenstein |
| author_sort | Jürgen Gräfenstein |
| collection | DOAJ |
| description | Calculations of nuclear magnetic resonance (NMR) isotopic shifts often rest on the unverified assumption that the “vibration hole”, that is, the change of the vibration motif upon an isotopic substitution, is strongly localized around the substitution site. Using our recently developed difference-dedicated (DD) second-order vibrational perturbation theory (VPT2) method, we test this assumption for a variety of molecules. The vibration hole turns out to be well localized in many cases but not in the interesting case where the H/D substitution site is involved in an intra-molecular hydrogen bond. For a series of salicylaldehyde derivatives recently studied by Hansen and co-workers (<i>Molecules</i> <b>2019</b>, <i>24</i>, 4533), the vibrational hole was found to stretch over the whole hydrogen-bond moiety, including the bonds to the neighbouring C atoms, and to be sensitive to substituent effects. We discuss consequences of this finding for the accurate calculation of NMR isotopic shifts and point out directions for the further improvement of our DD-VPT2 method. |
| first_indexed | 2024-03-10T18:54:43Z |
| format | Article |
| id | doaj.art-d378825b51644647b7af716c2c067f4b |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T18:54:43Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-d378825b51644647b7af716c2c067f4b2023-11-20T04:53:23ZengMDPI AGMolecules1420-30492020-06-012512291510.3390/molecules25122915The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic ShiftsJürgen Gräfenstein0Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, SwedenCalculations of nuclear magnetic resonance (NMR) isotopic shifts often rest on the unverified assumption that the “vibration hole”, that is, the change of the vibration motif upon an isotopic substitution, is strongly localized around the substitution site. Using our recently developed difference-dedicated (DD) second-order vibrational perturbation theory (VPT2) method, we test this assumption for a variety of molecules. The vibration hole turns out to be well localized in many cases but not in the interesting case where the H/D substitution site is involved in an intra-molecular hydrogen bond. For a series of salicylaldehyde derivatives recently studied by Hansen and co-workers (<i>Molecules</i> <b>2019</b>, <i>24</i>, 4533), the vibrational hole was found to stretch over the whole hydrogen-bond moiety, including the bonds to the neighbouring C atoms, and to be sensitive to substituent effects. We discuss consequences of this finding for the accurate calculation of NMR isotopic shifts and point out directions for the further improvement of our DD-VPT2 method.https://www.mdpi.com/1420-3049/25/12/2915NMR isotopic shiftsdifference-dedicated vibrational perturbation theorycyclic and polycyclic hydrocarbonshalonium-bonded complexesintra-molecular hydrogen bondssalicyl aldehyde derivatives |
| spellingShingle | Jürgen Gräfenstein The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts Molecules NMR isotopic shifts difference-dedicated vibrational perturbation theory cyclic and polycyclic hydrocarbons halonium-bonded complexes intra-molecular hydrogen bonds salicyl aldehyde derivatives |
| title | The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts |
| title_full | The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts |
| title_fullStr | The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts |
| title_full_unstemmed | The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts |
| title_short | The Structure of the “Vibration Hole” around an Isotopic Substitution—Implications for the Calculation of Nuclear Magnetic Resonance (NMR) Isotopic Shifts |
| title_sort | structure of the vibration hole around an isotopic substitution implications for the calculation of nuclear magnetic resonance nmr isotopic shifts |
| topic | NMR isotopic shifts difference-dedicated vibrational perturbation theory cyclic and polycyclic hydrocarbons halonium-bonded complexes intra-molecular hydrogen bonds salicyl aldehyde derivatives |
| url | https://www.mdpi.com/1420-3049/25/12/2915 |
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