Abstract

Distorted amides 3,4-dihydro-2-oxo-1,4-ethanoquinoline (1a), 3,4-dihydro-2-oxo-1,4-propanoquinoline (1b), 3,3,4,5-tetrahydro-2-oxo-1,5-ethanobenzazepine (1c), and 3,3,4,5-tetrahydro-2-oxo-1,5-propanobenzazepine (1d) and the model compounds 2,N-dimethyl-acetanilide (2a), 2,N,N-trimethylaniline (3), and benzoquinuclidine (4) have been studied calculationally and with He(I) ultraviolet photoelectron spectroscopy. We find good agreement between experimentally obtained ionization energies for 1b, 1c, 1d, 2a, 3, and 4 and values calculated with HAM/3 using the equilibrium geometries obtained at the HF/6-31G** level of theory. An excellent correlation between experimental ionization energies and orbital energies from Becke3LYP/6-31+G* calculations led to the characterization of the highest occupied molecular orbitals for these compounds and for 1a, whose photoelectron spectrum could not be obtained due to its reactivity in the solid state.