Photoelectron spectroscopy of carbonyls. 1,4-benzoquinones

Journal Article · Wed May 11 04:00:00 EDT 1977 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00452a005· OSTI ID:7100532

Dougherty, D; McGlynn, S P

He I photoelectron spectra have been obtained for 1,4-benzoquinone (PBQ) and some selected derivatives. A correlative study, which is based on the vibronic characteristics of the various ionization events and on the differential sensitivities of these events to chemical substitution (usually methylation, fluorination, or chlorination) on the benzenoid ring, leads to an MO assignment for the low-energy ionization regime. The assignment for PBQ, in order of decreasing MO energy, is n/sub -/ > n/sub +/ > ..pi../sub circled +/ > ..pi../sub -/; that for tetrafluoro-1,4-benzoquinone (TFPBQ) is n/sub +/ > n/sub -/ > ..pi../sub -/ > ..pi../sub circled +/. The perfluoro effect on PBQ induces shifts of the n orbitals which are approx.1 eV. The perfluoro shifts of the ..pi.. orbitals are somewhat smaller than those of the n orbitals. CNDO/2 computations provide uniformly poor agreement with the experimental data and retain no assignment utility unless used in a perturbative sense.

• Research Organization: Louisiana State Univ., Baton Rouge
• OSTI ID: 7100532
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 99:10; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400104* -- Spectral Procedures-- (-1987)
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
AROMATICS
BENZOQUINONES
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
MOLECULAR ORBITAL METHOD
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
QUINONES
SPECTROSCOPY