ELECTRONIC-SPECTRA AND STRUCTURE OF 2-IODOPICOLINES, THEIR N-OXIDES AND 2-IODO-4-NITROPICOLINE N-OXIDES

The UV spectra of 2-iodopicolines, their N-oxides and 2-iodo-4-nitropi coline N-oxides in ethanol have been examined and compared with the re sults (transition energies, intensities) of modified INDO calculations in order to make the assignment of allowed bands. The influence of su bstituents on the molecule on lambda(max) and epsilon(max) of spectral bands is discussed. The electronic spectra of 2-iodo-3-methyl-4-nitro pyridine and 2-iodo-5-methyl-4-nitropyridine N-oxides and the effect o f steric hindrance on the spectra are interpreted.