Through-bond interactions in the diradical intermediates formed in the rearrangements of bicyclo(n.m.0)alkatetraenes
The intermediates and transition structures in the degenerate thermal rearrangements of bicyclo[4.4.0]deca-2,4,7,9-tetraene (1c), bicyclo[5.5.0]dodeca-2,4,8,10-tetraene (11b), and bicyclo[5.4.0]undeca-2,4,8,10-tetraene (14) have been located by (U)B3LYP/6-31G(d) calculations. The singlet−triplet ene...
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| Main Authors: | , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
09/24/2010
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| In: |
Journal of the American Chemical Society
Year: 2010, Volume: 132, Issue: 41, Pages: 14617-14624 |
| ISSN: | 1520-5126 |
| DOI: | 10.1021/ja106329t |
| Online Access: | Resolving-System, lizenzpflichtig, Volltext: https://doi.org/10.1021/ja106329t Verlag, lizenzpflichtig, Volltext: https://pubs.acs.org/doi/10.1021/ja106329t 
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| Author Notes: | Charity Flener Lovitt, Hao Dong, David A. Hrovat, Rolf Gleiter, and Weston Thatcher Borden |
| Summary: | The intermediates and transition structures in the degenerate thermal rearrangements of bicyclo[4.4.0]deca-2,4,7,9-tetraene (1c), bicyclo[5.5.0]dodeca-2,4,8,10-tetraene (11b), and bicyclo[5.4.0]undeca-2,4,8,10-tetraene (14) have been located by (U)B3LYP/6-31G(d) calculations. The singlet−triplet energy differences (ΔEST) in the diradical intermediates (tricyclo[4.4.0.02,7]deca-3,8-dien-5,10-diyl (2c), tricyclo[5.5.0.05,11]dodeca-2,8-dien-4,10-diyl (12b), and tricyclo[5.4.0.05,11]undeca-2,8-dien-4,10-diyl (15)) have been computed, using both UB3LYP and (6/6)CASPT2 calculations. ΔEST in 2c, in which a four-membered ring is anti-bridged by two allylic radicals, is computed to be larger by a factor of 5 than ΔEST in 15, in which the anti-bridged ring is five-membered, and by a factor of 10 than that in 12b, in which the anti-bridged ring is six-membered. The reasons for the much larger interaction between two allylic radicals through the bonds of the four-membered ring in 2c than through the bonds of the five-membered ring in 15 or the six-membered ring in 12b are discussed, and the consequences of the large, through-bond stabilization of the singlet state of 2c are described. |
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| Item Description: | Im Titel steht der Ausdruck "n.m.0" in eckigen Klammern Gesehen am 19.04.2023 |
| Physical Description: | Online Resource |
| ISSN: | 1520-5126 |
| DOI: | 10.1021/ja106329t |