title: Stereoselective Fluorescence Quenching in the Electron Transfer Photooxidation of Nucleobase-Related Azetidines by Cyanoaromatics.
abstract: Electron transfer involving nucleic acids and their derivatives is an important field in bioorganic chemistry, specifically in connection with its role in the photo-driven DNA damage and repair. Four-membered ring heterocyclic oxetanes and azetidines have been claimed to be the intermediates involved in the repair of DNA (6-4) photoproduct by photolyase. In this context, we examine here the redox properties of the two azetidine isomers obtained from photocycloaddition between 6-aza-1,3-dimethyluracil and cyclohexene. Steady-state and time-resolved fluorescence experiments using a series of photoreductants and photooxidants have been run to evaluate the efficiency of the electron transfer process. Analysis of the obtained quenching kinetics shows that the azetidine compounds can act as electron donors. Additionally, it appears that thecisisomer is more easily oxidized than itstranscounterpart. This result is in agreement with electrochemical studies performed on both azetidine derivatives.
authors.affiliation: Instituto Mixto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda de los Naranjos s/n, 46022 Valencia, Spain. anfrati@itq.upv.es.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Fraga-Timiraos
authors.affiliation: Instituto Mixto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda de los Naranjos s/n, 46022 Valencia, Spain. gemrodmu@itq.upv.es.
authors.forename: Gemma M
authors.initials: GM
authors.lastname: Rodríguez-Muñiz
authors.affiliation: Instituto Mixto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda de los Naranjos s/n, 46022 Valencia, Spain. vipeipe@etsii.upv.es.
authors.forename: Vicente
authors.initials: V
authors.lastname: Peiro-Penalba
authors.affiliation: Instituto Mixto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda de los Naranjos s/n, 46022 Valencia, Spain. mmiranda@qim.upv.es.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
authors.affiliation: Instituto Mixto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda de los Naranjos s/n, 46022 Valencia, Spain. lvirgini@itq.upv.es.
authors.forename: Virginie
authors.initials: V
authors.lastname: Lhiaubet-Vallet
mesh_terms: D000873:Anthracenes / Q000737:chemistry*; D001384:Azetidines / Q000737:chemistry*; D004249:DNA Damage; D004579:Electron Transport; D005453:Fluorescence; D007700:Kinetics; D009281:Naphthalenes / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: C521244:9,10-dicyanoanthracene; D000873:Anthracenes; D001384:Azetidines; D009281:Naphthalenes; D009570:Nitriles
keywords: DNA repair; energy and charge transfer; nucleobase analogues; photolyase; redox potential