title: Excited state behaviour of substituted dipyridophenazine Cr(III) complexes in the presence of nucleic acids.
abstract: The photophysics and photochemistry of [Cr(phen)(2)(dppz)](3+) and its 11,12-substituted derivatives [Cr(phen)(2)(X(2)dppz)](3+) {X = Me or F} have been studied in the presence of purine nucleotides or DNA using steady state and time-resolved absorption and luminescence spectroscopy. 5'-Adenosine monophosphate (5'-AMP) shows only a weak interaction with the excited states of each complex. By contrast they are efficiently quenched by 5'-guanosine monophosphate (5'-GMP), consistent with photo-induced electron transfer. Laser flash photolysis spectroscopy in the presence of 5'-GMP suggests that both forward and back electron-transfers are rapid. All complexes also display a strong affinity for DNA and evidence for both static and dynamic quenching mechanisms is provided.
authors.affiliation: School of Chemistry, University of Dublin, Trinity College, College Green, Dublin 2, Republic of Ireland.
authors.forename: Michal
authors.initials: M
authors.lastname: Wojdyla
authors.forename: Jayden A
authors.initials: JA
authors.lastname: Smith
authors.forename: Suni
authors.initials: S
authors.lastname: Vasudevan
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Quinn
authors.forename: John M
authors.initials: JM
authors.lastname: Kelly
mesh_terms: D002857:Chromium / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004579:Electron Transport; D006157:Guanosine Monophosphate; D007364:Intercalating Agents / Q000737:chemistry; D010619:Phenazines / Q000737:chemistry*; D010782:Photolysis; D013050:Spectrometry, Fluorescence
chemical_list: D056831:Coordination Complexes; D007364:Intercalating Agents; D010619:Phenazines; C443808:dipyrido(3,2-a-2',3'-c)phenazine; D002857:Chromium; D006157:Guanosine Monophosphate; D004247:DNA