Photoprotolytic Processes of Lumazine
| Autor: | Dan Huppert, Ron Simkovitch |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Photolysis
Molecular Structure Proton 010405 organic chemistry Chemistry Pteridines Photodissociation Protonation 010402 general chemistry Photochemistry 01 natural sciences Fluorescence Tautomer 0104 chemical sciences Surfaces Coatings and Films Reaction rate Crystallography Deprotonation Materials Chemistry Molecule Physical and Theoretical Chemistry |
| Zdroj: | The Journal of Physical Chemistry B. 121:129-142 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/acs.jpcb.6b10828 |
| Popis: | Steady-state and time-resolved UV–vis spectroscopies were used to study the photoprotolytic properties of lumazine, which belongs to a class of biologically important compounds—the petridines. We found that in water an excited-state proton transfer occurs with a time constant of ∼70 ps and competes with a nonradiative rate of about the same value. The nonradiative rate of the protonated form of lumazine in polar and nonpolar solvents is large knr ≥ 1.5 × 1010s–1. The fluorescence properties indicate that in water, the ground-state neutral form of lumazine is already stable in two tautomeric forms. The fluorescence of the deprotonated form is quenched by protons in acidic solutions with a diffusion-controlled reaction rate. We conclude that the neutral form of lumazine is an irreversible mild photoacid. |
| Databáze: | OpenAIRE |
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