Electronic structures of pyridine N-oxide and 4-nitrosopyridine N-oxide

Abstract

The π-electron structure of pyridine N-oxide was calculated by the Pariser-Parr-Pople method, the effect of σ-polarization of the N→O bond upon the valence state ionization potentials and electron affinities being taken into account. By the aid of these results, the π-electron structure of 4-nitrosopyridine N-oxide was studied by the composite system method. The calculated transition energies and oscillator strengths can satisfactorly explain the observed electronic absorption spectrum. The 372 mμ band was ascribed to the charge-transfer transition from the oxygen atom of the N→O group to the nitroso group via the pyridine nucleus.