Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene
Bonding and aromaticity in the bowl-shaped <i>C</i><sub>5v</sub> and planar <i>D</i><sub>5h</sub> geometries of corannulene and the planar <i>D</i><sub>6h</sub> geometry of coronene are investigated using 3D isosurfaces and 2D c...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Chemistry |
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| Online Access: | https://www.mdpi.com/2624-8549/3/3/63 |
| _version_ | 1797519868782706688 |
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| author | Peter B. Karadakov |
| author_facet | Peter B. Karadakov |
| author_sort | Peter B. Karadakov |
| collection | DOAJ |
| description | Bonding and aromaticity in the bowl-shaped <i>C</i><sub>5v</sub> and planar <i>D</i><sub>5h</sub> geometries of corannulene and the planar <i>D</i><sub>6h</sub> geometry of coronene are investigated using 3D isosurfaces and 2D contour plots of the isotropic magnetic shielding <i>σ</i><sub>iso</sub>(<b>r</b>) and, for planar geometries, of the out-of-plane component of the shielding tensor <i>σ<sub>zz</sub></i>(<b>r</b>). Corannulene and coronene both feature conjoined shielded “doughnuts” around a peripheral six-membered carbon ring, suggesting strong bonding interactions and aromatic stability; a deshielded region inside the hub ring of corannulene indicates that this ring is antiaromatic, more so in planar corannulene. The switch from the planar to the bowl-shaped geometry of corannulene is shown to enhance both bonding and the local aromaticities of the five- and six-membered rings; these factors, in addition to ring strain reduction, favour the bowl-shaped geometry. The most and least shielded bonds in both corannulene and coronene turn out to be the spoke and hub bonds, respectively. The higher π electron activity over spoke bonds in planar corannulene and coronene is supported by <i>σ<sub>zz</sub></i>(<b>r</b>) contour plots in planes 1 Å above the respective molecular planes; these findings about spoke bonds are somewhat unexpected, given that ring current studies indicate next to no currents over spoke bonds. |
| first_indexed | 2024-03-10T07:48:53Z |
| format | Article |
| id | doaj.art-eb736900c1cb44dbbabcce1683aeaa66 |
| institution | Directory Open Access Journal |
| issn | 2624-8549 |
| language | English |
| last_indexed | 2024-03-10T07:48:53Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Chemistry |
| spelling | doaj.art-eb736900c1cb44dbbabcce1683aeaa662023-11-22T12:28:11ZengMDPI AGChemistry2624-85492021-08-013386187210.3390/chemistry3030063Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and CoronenePeter B. Karadakov0Department of Chemistry, University of York, Heslington, York YO10 5DD, UKBonding and aromaticity in the bowl-shaped <i>C</i><sub>5v</sub> and planar <i>D</i><sub>5h</sub> geometries of corannulene and the planar <i>D</i><sub>6h</sub> geometry of coronene are investigated using 3D isosurfaces and 2D contour plots of the isotropic magnetic shielding <i>σ</i><sub>iso</sub>(<b>r</b>) and, for planar geometries, of the out-of-plane component of the shielding tensor <i>σ<sub>zz</sub></i>(<b>r</b>). Corannulene and coronene both feature conjoined shielded “doughnuts” around a peripheral six-membered carbon ring, suggesting strong bonding interactions and aromatic stability; a deshielded region inside the hub ring of corannulene indicates that this ring is antiaromatic, more so in planar corannulene. The switch from the planar to the bowl-shaped geometry of corannulene is shown to enhance both bonding and the local aromaticities of the five- and six-membered rings; these factors, in addition to ring strain reduction, favour the bowl-shaped geometry. The most and least shielded bonds in both corannulene and coronene turn out to be the spoke and hub bonds, respectively. The higher π electron activity over spoke bonds in planar corannulene and coronene is supported by <i>σ<sub>zz</sub></i>(<b>r</b>) contour plots in planes 1 Å above the respective molecular planes; these findings about spoke bonds are somewhat unexpected, given that ring current studies indicate next to no currents over spoke bonds.https://www.mdpi.com/2624-8549/3/3/63aromaticityantiaromaticitycorannulenecoronenemagnetic shielding isosurfacesmagnetic shielding contour plots |
| spellingShingle | Peter B. Karadakov Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene Chemistry aromaticity antiaromaticity corannulene coronene magnetic shielding isosurfaces magnetic shielding contour plots |
| title | Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene |
| title_full | Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene |
| title_fullStr | Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene |
| title_full_unstemmed | Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene |
| title_short | Magnetic Shielding Study of Bonding and Aromaticity in Corannulene and Coronene |
| title_sort | magnetic shielding study of bonding and aromaticity in corannulene and coronene |
| topic | aromaticity antiaromaticity corannulene coronene magnetic shielding isosurfaces magnetic shielding contour plots |
| url | https://www.mdpi.com/2624-8549/3/3/63 |
| work_keys_str_mv | AT peterbkaradakov magneticshieldingstudyofbondingandaromaticityincorannuleneandcoronene |