Ricerc@Sapienza

We report here on the synthesis of four novel pyran-based DSSC photosensitizers. The dyes are constituted of a pyran core functionalized with different electron acceptor groups and with peripheral cyano-acrylic groups. The molecules were carefully characterized for what concerns optical and electrochemical properties and a clear dependence from the strength of the electron-acceptor group functionalizing the pyran core was observed. A detailed DFT analysis on the dyes gave a better insight of the electronic properties and showed a good accord with the experimental properties.

Photoionization mass spectrometry, photoelectron-photoion coincidence spectroscopic technique, and computational methods have been combined to investigate the fragmentation of two nitroimidazole derived compounds: the metronidazole and misonidazole. These molecules are used in radiotherapy thanks to their capability to sensitize hypoxic tumor cells to radiation by "mimicking" the effects of the presence of oxygen as a damaging agent.

Tunability and selectivity of synchrotron radiation have been used to study the excitation and ionization of 2-nitroimidazole at the C, N, and O K-edges. The combination of a set of different measurements (X-ray photoelectron spectroscopy, near-edge photoabsorption spectroscopy, Resonant Auger electron spectroscopy, and mass spectrometry) and computational modeling have successfully disclosed local effects due to the chemical environment on both excitation/ionization and fragmentation of the molecule.

The reaction dynamics and the temperature-dependent kinetic trend of the SO2.+ion-molecule reactions with water and methane have been studied using the tunable synchrotron radiation to produce excited SO2.+ions and ab-initio methods. The experimental results show that only one product, HSO2+, is formed in both reactions and its yield displays different trends with the photon energy. DFT and VTST calculations have been used to explore the dynamics of the reactions and to calculate the rate constants at different temperatures.