Fleischhauer, Jörg ; Raabe, Gerhard ; Klingensmith, Kenneth A. ; Höweler, Udo ; Chatterjee, Prabir K. ; Hafner, Klaus ; Vogel, Emanuel ; Michl, Josef (2005)
MCD of Non-aromatic Cyclic π-Electron Systems. Part 6: Pentalenes and Heptalenes.
In: International Journal of Quantum Chemistry, 102 (5)
doi: 10.1002/qua.20453
Article, Bibliographie
This is the latest version of this item.
Abstract
The magnetic circular dichroism (MCD) spectra of several stable derivatives of pentalene (1) and heptalene (2) have been recorded. The lowest energy transition (from the ground to the S state in perimeter model nomenclature) is extremely weak in MCD and in absorption. The sign patterns of the B terms for the first three strong transitions—N₁, N₂, P₁—in the order of increasing energy, are −−+ for 1 and ++− for 2. These findings are in perfect agreement with numerical results obtained at the SACCI level and with expectations based on the perimeter model of Parts 1–4 of this series, both of which lead to the conclusion that the magnetic mixing of the S excited state with the ground state is dominant. This is an extremely rare situation for an organic molecule, in which B term signs are normally determined by the mutual magnetic mixing of excited states. It can be expected to occur in other conjugated systems derived from 4N-electron perimeters that have a low-energy first excitation, which is of intrashell nature in the perimeter model and therefore is magnetic-dipole allowed. In contrast, all low-energy transitions in the much more common systems derived from (4N + 2)-electron perimeters are of intershell nature and are magnetic-dipole forbidden.
| Item Type: | Article |
|---|---|
| Erschienen: | 2005 |
| Creators: | Fleischhauer, Jörg ; Raabe, Gerhard ; Klingensmith, Kenneth A. ; Höweler, Udo ; Chatterjee, Prabir K. ; Hafner, Klaus ; Vogel, Emanuel ; Michl, Josef |
| Type of entry: | Bibliographie |
| Title: | MCD of Non-aromatic Cyclic π-Electron Systems. Part 6: Pentalenes and Heptalenes |
| Language: | English |
| Date: | 2005 |
| Place of Publication: | Darmstadt |
| Publisher: | Wiley |
| Journal or Publication Title: | International Journal of Quantum Chemistry |
| Volume of the journal: | 102 |
| Issue Number: | 5 |
| DOI: | 10.1002/qua.20453 |
| Corresponding Links: | |
| Abstract: | The magnetic circular dichroism (MCD) spectra of several stable derivatives of pentalene (1) and heptalene (2) have been recorded. The lowest energy transition (from the ground to the S state in perimeter model nomenclature) is extremely weak in MCD and in absorption. The sign patterns of the B terms for the first three strong transitions—N₁, N₂, P₁—in the order of increasing energy, are −−+ for 1 and ++− for 2. These findings are in perfect agreement with numerical results obtained at the SACCI level and with expectations based on the perimeter model of Parts 1–4 of this series, both of which lead to the conclusion that the magnetic mixing of the S excited state with the ground state is dominant. This is an extremely rare situation for an organic molecule, in which B term signs are normally determined by the mutual magnetic mixing of excited states. It can be expected to occur in other conjugated systems derived from 4N-electron perimeters that have a low-energy first excitation, which is of intrashell nature in the perimeter model and therefore is magnetic-dipole allowed. In contrast, all low-energy transitions in the much more common systems derived from (4N + 2)-electron perimeters are of intershell nature and are magnetic-dipole forbidden. |
| Uncontrolled Keywords: | magnetic circular dichroism; pentalene; heptalene; perimeter model |
| Classification DDC: | 500 Science and mathematics > 540 Chemistry |
| Divisions: | 07 Department of Chemistry 07 Department of Chemistry > Clemens-Schöpf-Institut 07 Department of Chemistry > Clemens-Schöpf-Institut > Organ Chemistry |
| Date Deposited: | 02 Aug 2024 12:45 |
| Last Modified: | 02 Aug 2024 12:45 |
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| Suche nach Titel in: | TUfind oder in Google |
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MCD of Non-aromatic Cyclic π-Electron Systems. Part 6: Pentalenes and Heptalenes. (deposited 28 Nov 2022 09:11)
- MCD of Non-aromatic Cyclic π-Electron Systems. Part 6: Pentalenes and Heptalenes. (deposited 02 Aug 2024 12:45) [Currently Displayed]
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