ISSN:
0009-2940
Schlagwort(e):
Triblattanes
;
PE
;
Orbital sequence
;
Calculations
;
Chemistry
;
Inorganic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The He(I)-PE spectra of the parent [1.1.1]-, [2.1.1]-, [2.2.1]-, and [2.2.2]triblattanes 1-4, of their unsaturated or ketonic congeners 5-13 and benzo derivatives 14-20 have been recorded. For 1-4, the energy difference between the highest occupied orbitals (e” and a' mainly localized at the central bicyclo-[2.2.2]octane unit) and the subsequent MOs increases with increasing number of ethano bridges. This observation is rationalized by using a first-order perturbation-theoretical approach. The analysis of the PE spectra of the exo-methylene (5-7), ketone (8-10), and endo-olefinic derivatives (11-13) unveils a strong π/σ mixing. The splitting of the π-bands in 7 (0.95 eV) and 13 (1.0 eV), respectively, is traced back to a stronger π/σ mixing of the e MOs as compared to the a2 MOs. An analogous interaction causes the splitting of the first bands of the ketones 8-10 (0.45-1.49 eV). For the benzo derivatives 14-20 the split of the π-bands is relatively small (0.35-0.7 eV).
Zusätzliches Material:
12 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/cber.19931261019
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