| Popis: |
Numerous studies suggest that photostability is one of the intrinsic properties of the prebiotic nucleobases used to survive the extreme environmental conditions in the early Earth. The excited state deactivation pathways of the canonical nucleobases, guanine, adenine, cytosine, thymine, and uracil, have been widely studied, resulting in ultrafast internal conversion to the ground state. Recent investigations suggested that the amino and carbonyl substitution influence the photophysical properties of these purine and pyrimidine nucleobases. In particular, it has been shown that functionalization of the purine chromophore with an amino or a carbonyl group at the C2 or C6 position significantly affects the excited state dynamics of these derivatives. For this reason, the motivation of this thesis is to elucidate the photophysics and excited state dynamics of a group of selected purine derivatives in solution to understand how functionalization controls the photostability of the DNA and RNA nucleobases. In this thesis, the study of the selected purine derivatives was performed using steady-state absorption and emission spectroscopies, broadband transient absorption spectroscopy, and quantum chemical calculations. |
