UV ABSORPTION SPECTRA AND REACTION PATHWAYS FOR SULFONYL- DIHYDROPYRIDINE AND FUSED DERIVATIVES THROUGH (TD)DFT CALCULATIONS.

COOKE, MARIA VICTORIA; FIRPO, GUADALUPE; PELAEZ, WALTER J.; ARGÜELLO, GUSTAVO

Exposición; 3rd School of Theoretical and Computational Chemistry in the Americas; 2015

A detailed analysis of the MOs involved in electronic transitions in UV spectra as well as a conformational study of some 1-benzenesulfonyl- and 1-trifluoromethylsulfonyl derivatives have been carried out using the TD-DFT (B3LYP/6-31+G(d,p)) method. Based on experimental solvent effects and theoretical investigations the long-wavelength bands have been assigned to Pi-Pi* transitions caused by HOMO-LUMO intramolecular charge transfer of the systems. Nevertheless, for one of the 1-benzenesulfonyl- (p-NO2) derivative the HOMO-LUMO transition was found to be forbidden. In this case the long-wavelength band has been associated to an n-Pi* transition. Good correlation of theoretical and experimental data for the energy transitions and the molar extinction coefficients of the compounds studied has been obtained and is presented for the first time.