The electronics structures of small strained rings. An investigation of the interaction between the oxygen and the π orbitals in 3-methyleneoxetane and 3-oxetanone

The ultraviolet photoelectron spectra of 3-methyleneoxetane (I), 3-oxetanone (II) and β-propiol-octane (III) have been investigated for the purpose of studying the interaction processes between the endocyclic oxygen and the methylene or carbonyl groups of I and II, respectively. Molecular orbital calculations at the MINDO/3, MNDO, and STO-3G/431-G levels have been performed to aid analyses of the data. The interaction process occurs primarily through the pseudo-π-CH₂ orbitals for I and II. Substantial stabilizing inductive effects are noted for the lone-pair and π orbitals for these molecules.