Excited state dynamics of protonated dopamine: hydration and conformation effects

Abstract

Electronic and vibrational spectroscopy in a cryogenic ion trap have been applied to protonated dopamine water clusters and assigned with the help of quantum chemistry calculations performed in the ground...

Conformer‐selective Photodynamics of TrpH+−H2O

“…In water clusters, due to the strong electrostatic interaction, the protonated ammonium group gets solvated by the first solvent molecules, impeding the direct interaction of the charged group with the ring and thus blocking the ESPT reaction. [24] We here report new experimental results on the photophysics of TrpH + and TrpH + -H2O complex, supported by quantum chemistry calculations. We have investigated the photodynamics of TrpH + at the band origin and measured the excited state lifetime of the ESPT form.…”

“…In both cases, calculations predict ESPT from the ammonium to the aromatic ring with no or low energy barrier, providing an efficient and fast deactivation pathway. In water clusters, due to the strong electrostatic interaction, the protonated ammonium group gets solvated by the first solvent molecules, impeding the direct interaction of the charged group with the ring and thus blocking the ESPT reaction [24] …”

“…In water clusters, due to the strong electrostatic interaction, the protonated ammonium group gets solvated by the first solvent molecules, impeding the direct interaction of the charged group with the ring and thus blocking the ESPT reaction. [24] …”

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

“…DA. Given that the results for dopamine have already been reported, 54,55 only the excited states of the graphene sheet and binary complexes will be discussed in more detail. Briefly, DA presents spectral characteristics with peak maxima at 280 nm and 218 nm (see Fig.…”

“…47 But what makes it particularly more interesting is the photochemical application of the graphene-dopamine complex, [48][49][50][51][52] especial as photothermal therapy for cancer. 53 Although DA is a relatively small molecule, its photochemical behaviour strongly dependents on its the concentration and tautomer forms as well as on the pH of the solvent environment, 54,55 and it is therefore much more difficult to unambiguously identify the fingerprints of different tautomers in the experimental UV-Vis spectrum. Similarly to DA, graphene exhibits complex photochemical behaviour, as the shape of the spectrum is highly dependent on the atomic configuration and size of the graphene structure.…”