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
Artikel, Bibliographie
Dies ist die neueste Version dieses Eintrags.
Kurzbeschreibung (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.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2005 |
| Autor(en): | Fleischhauer, Jörg ; Raabe, Gerhard ; Klingensmith, Kenneth A. ; Höweler, Udo ; Chatterjee, Prabir K. ; Hafner, Klaus ; Vogel, Emanuel ; Michl, Josef |
| Art des Eintrags: | Bibliographie |
| Titel: | MCD of Non-aromatic Cyclic π-Electron Systems. Part 6: Pentalenes and Heptalenes |
| Sprache: | Englisch |
| Publikationsjahr: | 2005 |
| Ort: | Darmstadt |
| Verlag: | Wiley |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | International Journal of Quantum Chemistry |
| Jahrgang/Volume einer Zeitschrift: | 102 |
| (Heft-)Nummer: | 5 |
| DOI: | 10.1002/qua.20453 |
| Zugehörige Links: | |
| Kurzbeschreibung (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. |
| Freie Schlagworte: | magnetic circular dichroism; pentalene; heptalene; perimeter model |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Fachbereich(e)/-gebiet(e): | 07 Fachbereich Chemie 07 Fachbereich Chemie > Clemens-Schöpf-Institut 07 Fachbereich Chemie > Clemens-Schöpf-Institut > Fachgebiet Organische Chemie |
| Hinterlegungsdatum: | 02 Aug 2024 12:45 |
| Letzte Änderung: | 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) [Gegenwärtig angezeigt]
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