Photoelectron spectra of substituted acetophenones. Correlations with reactivity

Abstract

E. J. MCALDUFF. Can. J. Chem. 58,622 (1980). Ultraviolet photoelectron spectra of 4-R-acetophenones (R = N(CH,),. 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 no I$ with redox potentials, nmr chemical shifts of acetyl protons. and chemicai reactivity data. Both Ph, and no IP's correlate with Hammetto,constants of the substituent and Phs IP's are found to be linearly related to the first IP's of the analogous monosubstituted benzenes. E. J. MCALDUFF. Can. J. Chem. 58,622 (1980) On adlterminl ies spectres photoelectroniques ultraviolets de R-4acltophenones (R = N(CH,),, t-Bu, C1) et on aattribue les trois potentiels d'ionisation les plus faibles. Ces donnkes cornbinees a celles de la litterature relatives a d'autres R-4 acetophenones permettent des correlations de n,PI avec les potentiels redox, les diplacements chimiques en rmn des protons du groupe acktyte et avec les donnees derkactivite chimique. I1 existe une correlation entre lesPh, ainsi que IesPI, avecles constanteso, de Hammettdes substituants et on a trouve qu'il existe une relation lineaire entre les Ph, ainsi que les premiers PI'S des benzenes monosubstitues analogues.[Traduit par le journal]Introduction and parn to it and high electron density at the orfho Ultravioiet photoelectron spectroscopy provides and mera positions. En theory it should be possible a method the effects of substituents to distinguish between acetopherlone reactions ocon valence orbital ionization potentials. One of the c"r"ng at the carbony1 oxygen and those occurring main empirical approaches to the problem of the "1 the phenyl ring in that the former rates should effects of substituenls on reactivity has been the correlate better with no IP and the latter with use of linear free energy correlations. Since sub-phenyl-type lP's. stituted benzene systems are prime examples ofThe PE spectra of a wide variety of substituted cases where linear free energy relationships are acetophenones have been previously published