Microwave assisted organic synthesis of benzophenothiazines: Photophysical and DFT calculations studies

The present paper brings two different photochemical aspects of benzophenothiazine chemistry: (i) the use of microwave radiation to prepare three benzophenothiazines derivates; and (ii) the photophysical characterization of the isolated compounds from microwave reactions by absorption and emission spectroscopy supported by DFT calculations at B3LYP/6-31G(d,p)/PCM level. The microwave assistant reactions reduced the reactions times compared with the conventional methods, but gave the same regioselectivity. The DFT study of the ground and excited states by linear response and state specific TD-DFT, absorption and emission, vibronic resolved spectra and charge analysis showed a very good correlation with the experimental results, and point out the benzothiazine moiety as the key element of the photophysical activity.