Excited electronic states of 2-ethylamino-(3 or 5)-methyl-4-nitropyridine and 2-methylamino-(3 or 5)-methyl-4-nitropyridine

Electronic absorption spectra of 2-methylamino-, 2-ethylamino-3-methyl-4-nitropyridine and 2-ethylamino-, 2-methylamino-5-methyl-4- nitropyridine in the solid state and ethyl alcohol solution have been measured at room temperature. Their luminescence spectra and life times have been recorded at room and liquid helium temperatures. The energy sequence of the singlet and triplet states has been calculated for optimised geometry of the molecules and compared to the experimental values. The results of ab initio TD DFT quantum calculations using MPW1PW91 density functional 6-31G(d,p) basis set have been analysed. q 2004 Elsevier B.V. All rights reserved