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Interactions between Oxygen Lone-Pair Orbitals and Double-Bond π-Orbitals in β,γ-Unsaturated,Bicyclic Ketones; a PE-Spectroscopic Investigation |
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| Authors: | Pierre-Alain Carrupt Raphy Gabioud Albino Rubello Pierre Vogel Evi Honegger Edgar Heiloronner |
| Affiliation: | 1. Institut de Chimie organiqu de 1'Université de Lausanne, 2, rud de la Barre, CH–1005 Lausanne;2. Institut de Chimie organiqu de 1'Université de Lausanne, 2, rud de la Barre, CH–1005 Lausanne Pierre Vogel, Institut de Chimie organiqu de 1'Université de Lausanne, 2, rud de la Barre, CH–1005 Lausanne Edgar Heiloronner, Institut für Physikalische Chemie der Universität Basel, Klingelbergstrasse 80, CH–4056 Basel;3. Institut für Physikalische Chemie der Universität Basel, Klingelbergstrasse 80, CH–4056 Basel;4. Institut für Physikalische Chemie der Universität Basel, Klingelbergstrasse 80, CH–4056 Basel Pierre Vogel, Institut de Chimie organiqu de 1'Université de Lausanne, 2, rud de la Barre, CH–1005 Lausanne Edgar Heiloronner, Institut für Physikalische Chemie der Universität Basel, Klingelbergstrasse 80, CH–4056 Basel |
| Abstract: | The HE(Iα) photoelectron (PE) spectra of 2,3,5,6-tetramethylidene-2-bicyclo[2.2.1]heptanone ( 12 ), 5,6-dimethylidene-2-bicyclo[2.2.1]heptanone ( 14 ), 5,6-dimethylidene-2-bicyclo[2.2.2]octanone ( 16 ), and 5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octanone ( 17 ) have been recorded, Comparison with the PE data of other β,γ-unsaturated ketones and parent alkenes, and with the result of ab initio STO-3G calculations, confirm the existence of significant interactions between the oxygen lone-pair orbital no and the double-bond π orbital(s). It is argued that the major contributions to the basis energy shifts and to the cross term between the no and π orbitals are due to a ‘through-bond’ mechanism. |
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