ABSORPTION-SPECTRA OF NITRO-DERIVATIVES - 2-ALKYLAMINO-4-NITROPICOLINES AND THEIR N-OXIDES

The UV spectra of fifteen 2-N-substituted 4-nitropicolines and their N -oxides in ethanol have been determined. The spectra of all investigat ed compounds with exception of 2-alkylnitramino-4-nitropicolines conta in three main bands: two absorption derive from pi --> pi* excitation of pi-electron of the aromatic system. The third ICT in the longest wa velength region is assigned to 4-nitro group via pyridine ring. The ba nds in the spectra of 3-methyl derivatives are characterized by smalle r intensity than 5-methyl derivatives due to disturbance of mutual ele ctronic interaction of substituent by a steric ortho effect.