Photoelectron spectra of substituted acetophenones. Correlations with reactivity

Ultraviolet photoelectron spectra of 4-R-acetophenones (R = N(CH 3 ) 2 , t-Bu, Cl) have been determined and the three lowest ionization potentials assigned. Combination of these data with literature data on other 4-R-acetophenone allows correlations of n O IP with redox potentials, nmr chemical shifts of acetyl protons, and chemical reactivity data. Both Ph S and n O IP's correlate with Hammett σ P constants of the substituent and Ph S IP's are found to be linearly related to the first IP's of the analogous monosubstituted benzenes.