Photoinduced water oxidation in pyrimidine–water clusters: a combined experimental and theoretical study

Abstract

The photochemical oxidation of water molecules in pyrimidine–water complexes has been explored in a combined experimental and theoretical study.

Revealing the role of excited state proton transfer (ESPT) in excited state hydrogen transfer (ESHT): systematic study in phenol–(NH3)n clusters

“…Extension of the ESHT reaction to describe other processes is now occurring, notably in the description of excited state H abstraction by aromatic molecules, which is the reverse process of ESHT and is demonstrated in photoexcited pyridine-H 2 O system. [80][81][82][83] These…”

Microhydration of ionized building blocks of DNA/RNA: infrared spectra of pyrimidine$$^{+}$$-$$(\hbox {H}_{2}\hbox {O})_{\text {1-3}}$$ clusters

“…Comparison with the previously studied Pym + -(N 2 ) n clusters using the same spectroscopic and computational approach [47] illustrates the effect of solvent polarity on the interaction potential with respect to both structure (preferred binding sites and solvation network) and binding energy. We also compare our results for Pym + -W with the properties of neutral Pym-W [43,[48][49][50][51] to evaluate the effect of ionization on structure, binding motif, and interaction energy, which is fundamental to comprehend the charge-induced changes arising in solvent binding motifs of biologically relevant molecules.…”

Can Hydrated Electrons be Produced from Water with Visible Light?

“…The sustainable production of hydrated electrons requires that the electrons are obtained by photooxidation of water. Recently, it has been demonstrated in molecular beam experiments that the chromophores pyridine (Py) and pyrimidine (Pm) can catalytically photooxidize water molecules in hydrogen-bonded Py•••(H 2 O) n and Pm•••(H 2 O) n clusters via an excitedstate proton-coupled electron transfer (PCET) reaction, resulting in the formation of PyH and PmH radicals, which were detected via their electronic spectra [34,35] (here and in the following the dots indicate a hydrogen bond). As radicals, PyH and PmH possess absorbing excited states in the visible range of the spectrum.…”

“…It was shown computationally that these hypervalent radicals possess, in addition, low-lying dark excited states of 2 πσ* character which are dissociative with respect to the NH bond distance. [35,36] These 2 πσ* states can drive direct (nonstatistical) photodetachment of the excess hydrogen atom from the PyH radical. This reaction could be experimentally detected in PyH•••(H 2 O) n clusters.…”

“…As radicals, PyH and PmH possess absorbing excited states in the visible range of the spectrum. It was shown computationally that these hypervalent radicals possess, in addition, low‐lying dark excited states of 2 πσ* character which are dissociative with respect to the NH bond distance [35,36] . These 2 πσ* states can drive direct (nonstatistical) photodetachment of the excess hydrogen atom from the PyH radical.…”