In:
Helvetica Chimica Acta, Wiley, Vol. 68, No. 1 ( 1985-02-13), p. 23-38
Abstract:
The σ‐orbital manifold of cubane 1 , as suggested by its PE spectrum, is divided into two sets separated by a 3 eV gap extending from ∼ ‐10.5 eV to ∼ ‐13.5 eV. Halogen substituents with np AO basis energies falling into this gap ( e.g. Cl or Br) will, therefore, hyperconjugate appreciably with both sets. Interaction with the lower‐lying set will lead to the usual destabilization (‘normal’ hyperconjugation), whereas interaction with the set above will necessarily lead to a ‘stabilization’ (‘inverted’ hyperconjugation). As a result the lone‐pair ionization energies of Cl or Br substituted cubanes (derived from PE spectra) are much larger than naively expected for an alkyl halide containing as much as 8 C‐atoms. In particular no significant shift of the e lone‐pair bands in the PE spectra of 1,4‐dichloro‐ and 1,4‐dibromocubane can be detected with respect to the first ionization energies of the free atoms Cl and Br, or of HCl and HBr.
Type of Medium:
Online Resource
ISSN:
0018-019X
,
1522-2675
DOI:
10.1002/hlca.19850680104
Language:
English
Publisher:
Wiley
Publication Date:
1985
detail.hit.zdb_id:
74-7
detail.hit.zdb_id:
1475013-2
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