Electronic structure and photochemical interconversions of dihydropentalene radical cations

Journal Article · Wed Aug 02 04:00:00 EDT 1995 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00135a010· OSTI ID:111187

Bally, T; Truttmann, L ^[1]; Wang, J T; Williams, F ^[2]

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1. Univ. of Fribourg (Switzerland)
2. Univ. of Tennessee, Knoxville, TN (United States)

Starting from the recently characterized radical cation of bicyclo[3,3,0]octa-2,6-diene-4,8-diyl, four additional dihydropentalene radical cations (DHP{sup -4}) can be formed by phototautomerization in Freon glasses and argon matrices where they can be characterized by optical (Freon, argon) and ESR spectroscopy (Freon). Two of these DHP isomers can be prepared independently, while the cations of the other two are identified by analogy of their spectra with those of related compounds. The electronic structure of 1,2-, 1,4-, and 1,5-DHP{sup +}, which have linear and cross-conjugated triene {pi}-systems is discussed on the basis of their photoelectron and optical spectra and INDO/S calculations. The part of the C{sub 8}H{sub 8}{sup +} potential surface comprising all ten possible DHP{sup +} tautomers and some related valence isomers is explored by high-level ab initio calculations. An FMO-based set of rules for sigmatropic rearrangements in radical cations is presented and serves to rationalize the observed H-shifts. 40 refs., 12 figs., 4 tabs.

• Sponsoring Organization: USDOE
• DOE Contract Number: FG05-88ER13852
• OSTI ID: 111187
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 30 Vol. 117; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ABSORPTION SPECTRA
AROMATICS
CATIONS
CHEMICAL PREPARATION
CYCLOALKENES
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
ISOMERIZATION
ISOMERS
MOLECULAR ORBITAL METHOD
PHOTOCHEMICAL REACTIONS
POTENTIALS
RADICALS