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Electronic and Molecular Structure of the C 8 H 10 +· Valence Isomers 1,3,5‐Cyclooctatriene +· and Bicyclo[4.2.0]octa‐2,4‐diene +· from their Electronic absorption Spectra in Freon
Author(s) -
Bally Thomas,
Roth Kuno,
Straub Rolf
Publication year - 1989
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19890720110
Subject(s) - chemistry , mndo , ionization , electronic structure , metastability , valence (chemistry) , spectral line , bicyclic molecule , freon , ionization energy , absorption spectroscopy , crystallography , stereochemistry , computational chemistry , molecule , ion , organic chemistry , physics , quantum mechanics , astronomy
The molecular cations of 1,3,5‐cyclooctatriene (COT +· ) and bicyclo[4.2.0]octa‐2,4‐diene (BCO +· ) can be observed intact in γ‐irradiated Freon glasses, as opposed to Ar matrices where ionization is accompanied by extensive rearrangements. This proves the superiority of the Freon ‐glass method for the generation of metastable primary cations. The electronic absorption (EA) spectra reveal a ) that a previous analysis of the BCO +· electronic structure on the basis of the ultraviolet photoelectron (UP( spectrum of BCO was incomplete, and b ) that COT undergoes planarization upon ionization, in accord with qualitative expectations and MNDO calculations. A previously proposed LCBO model was used to assess the influence of the above geometry change on the electronic structure of COT +· .