Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths?
The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (<b>1</b>) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tri...
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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/1420-3049/25/12/2778 |
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| author | Joseph R. Lane Graham C. Saunders |
| author_facet | Joseph R. Lane Graham C. Saunders |
| author_sort | Joseph R. Lane |
| collection | DOAJ |
| description | The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (<b>1</b>) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide (<b>2</b>) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of <b>1</b>, which comprises lone pair–π, weak hydrogen bonding and C–H∙∙∙arene interactions, has energies of 70 and 71 kJ mol<sup>−1</sup>. The attraction between molecules of <b>2</b> comprises two lone pair–π interactions, and has energies of 99 and 100 kJ mol<sup>−1</sup>. There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of <b>1</b>. For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for <b>2</b>, and so there is no difference between the P=O distances of <b>2</b>. |
| first_indexed | 2024-03-10T19:08:24Z |
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| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T19:08:24Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
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| series | Molecules |
| spelling | doaj.art-b989dcbbbfe847e5bb9ff8ad31d6155b2023-11-20T04:01:06ZengMDPI AGMolecules1420-30492020-06-012512277810.3390/molecules25122778Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths?Joseph R. Lane0Graham C. Saunders1School of Science, University of Waikato, Hamilton 3240, New ZealandSchool of Science, University of Waikato, Hamilton 3240, New ZealandThe crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (<b>1</b>) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide (<b>2</b>) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of <b>1</b>, which comprises lone pair–π, weak hydrogen bonding and C–H∙∙∙arene interactions, has energies of 70 and 71 kJ mol<sup>−1</sup>. The attraction between molecules of <b>2</b> comprises two lone pair–π interactions, and has energies of 99 and 100 kJ mol<sup>−1</sup>. There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of <b>1</b>. For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for <b>2</b>, and so there is no difference between the P=O distances of <b>2</b>.https://www.mdpi.com/1420-3049/25/12/2778phosphine oxidesX-ray crystal structuredensity functional theory calculations |
| spellingShingle | Joseph R. Lane Graham C. Saunders Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths? Molecules phosphine oxides X-ray crystal structure density functional theory calculations |
| title | Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths? |
| title_full | Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths? |
| title_fullStr | Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths? |
| title_full_unstemmed | Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths? |
| title_short | Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths? |
| title_sort | theoretical study of the structures of 4 2 3 5 6 tetrafluoropyridyl diphenylphosphine oxide and tris pentafluorophenyl phosphine oxide why does the crystal structure of tetrafluoropyridyl diphenylphosphine oxide have two different p o bond lengths |
| topic | phosphine oxides X-ray crystal structure density functional theory calculations |
| url | https://www.mdpi.com/1420-3049/25/12/2778 |
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