title: Kinetics of the oxidation of thymine and thymidine by triplet 2,2'-dipyridyl in aqueous solutions at different pH values.
abstract: The photo-oxidation of the nucleobase, thymine (Thy), and nucleoside, thymidine (dThy), by dipyridyl (DP) has been investigated in aqueous solution using time-resolved laser flash photolysis. The pH dependence of the oxidation rate constants is measured within a large pH scale. As a consequence, the chemical reactivity of the reactants existing in solution at a certain range of pH is predicted. Bimolecular rate constants of the quenching reactions between triplet dipyridyl and thymine and thymidine are, respectively, kq = 2.4 × 10(7) M(-1) s(-1) (pH < 5.8) and kq = 1.0 × 10(7) M(-1) s(-1) (5.8 < pH < 9.8). Cyclic voltammetry was used to measure the potentials of thymine oxidation and dipyridyl reduction in water at pH < 7. Both results give hints for a proton coupled electron-transfer (PCET) reaction from thymine to triplet dipyridyl.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria. truong.nguyenxuan@hust.edu.vn
authors.forename: Truong X
authors.initials: TX
authors.lastname: Nguyen
authors.forename: Günter
authors.initials: G
authors.lastname: Grampp
authors.forename: Alexandra V
authors.initials: AV
authors.lastname: Yurkovskaya
authors.forename: Nikita
authors.initials: N
authors.lastname: Lukzen
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010084:Oxidation-Reduction; D012996:Solutions; D013936:Thymidine / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D012996:Solutions; D014867:Water; D015082:2,2'-Dipyridyl; D013941:Thymine; D013936:Thymidine
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