Application of photoelectron spectroscopy to intramolecularly hydrogen-bonded systems. Part III. The photoelectron spectra of cis and trans 2-substituted cyclopentanols and cis and trans 2-substituted cyclohexanols

Abstract

R. S. BROWN. Can. J. Chem. 54,1929Chem. 54, (1976. The photoelectron spectra of several well defined molecules exhibiting intramolecular hydrogen bonding has been determined and the analysis of the spectra is in accord with recent molecular orbital calculations of related systems. The experimentally determined enthalpies of the hydrogen bonds in cis-2-aminocyclopentanol and cis-and trans-2-aminocyclohexanol d o not correlate in any simple fashion with the shifts in the ionization energies of the no and nN orbitals compared t o a model which precludes hydrogen bonding. The spectral differences attributed to hydrogen bonding in the cis and tratls 2-substituted cyclanols cannot be attributed to differences in the through-bond interaction of the n orbitals on either atom since the cis and trarrs isomers of 1,2-dimethoxycyclopentane and 1,2-dimethoxycyclohexane show virtually identical pe spectra. A discussion of the applicability of Koopmans' theorem and the effect of the hydrogen bond in both the ion and ground states is presented.