L. Klasinc, B. Ruscic, F. Kajfez, and V. Sunjic, Int. J. Quantum Chem. Quantum Biol. Symp. 5, 367-371 (1978)

Photoelectron Spectroscopy of the Heterocycles. Imidazole and Methylimidazoles

L. Klasinc,^a B. Ruščić,^a F. Kajfež,^b and V. Šunjić^b

^a Rugjer Bošković Institute, Zagreb, Croatia
^b Department of Biomedical and Biochemical Research, CRC-Chemical Research Company, San Giovanni al Natisone, Italy

Int. J. Quantum Chem.: Quantum Biol. Symp. 5, 367-371 (1978)

The He(I) photoelectron (PE) spectra of imidazole, 1-methylimidazole, 2-methylimidazole, and 4(5)-methylimidazole are reported. The electronic structure of imidazole is discussed on the basis of high resolution spectra and molecular orbital (MO) calculations. Methyl substitution in imidazole, apart from a nearly constant destabilization of low-energy ionizations, causes a negligible change in the shape of its PE spectrum. This was probably the reason why there was no indication for the presence of two tautomers in the PE spectrum of 4(5)-methylimidazole.