Computational Analysis of the Behavior of BODIPY Decorated Monofunctional Platinum(II) Complexes in the Dark and under Light Irradiation

Dual-action drugs are occupying an important place in the scientific landscape of cancer research owing to the possibility to combine different therapeutic strategies into a single molecule. In the present work, the behavior of two BODIPY-appended monofunctional Pt­(II) complexes, one mononuclear and one binuclear, recently synthesized and tested for their cytotoxicity have been explored both in the dark and under light irradiation. Quantum mechanical DFT calculations have been used to carry out the exploration of the key steps, aquation and guanine attack, of the mechanism of action of Pt­(II) complexes in the dark. Due to the presence of the BODIPY chromophore and the potential capability of the two investigated complexes to work as photosensitizers in PDT, time dependent DFT has been employed to calculate their photophysical properties and to inspect how the sensitizing properties of BODIPY are affected by the presence of the platinum “heavy atom”. Furthermore, also the eventual influence on of the photophysical properties due to the displacement of chlorido ligands by water and of water by guanine has been taken into consideration.