title: Excited state dependent electron transfer of a rhenium-dipyridophenazine complex intercalated between the base pairs of DNA: a time-resolved UV-visible and IR absorption investigation into the photophysics of fac-[Re(CO)3(F2dppz)(py)]+ bound to either [poly(dA-dT)]2 or [poly(dG-dC)]2.
abstract: The transient species formed following excitation of fac-[Re(CO)(3)(F(2)dppz)(py)](+) (F(2)dppz = 11,12-difluorodipyrido[3,2-a:2',3'-c]phenazine) bound to double-stranded polynucleotides [poly(dA-dT)](2) or [poly(dG-dC)](2) have been studied by transient visible and infra-red spectroscopy in both the picosecond and nanosecond time domains. The latter technique has been used to monitor both the metal complex and the DNA by monitoring the regions 1900-2100 and 1500-1750 cm(-1) respectively. These data provide direct evidence for electron transfer from guanine to the excited state of the metal complex, which proceeds both on a sub-picosecond time scale and with a lifetime of 35 ps, possibly due to the involvement of two excited states. No electron transfer is found for the [poly(dA-dT)](2) complex, although characteristic changes are seen in the DNA-region TRIR consistent with changes in the binding of the bases in the intercalation site upon excitation of the dppz-complex.
authors.affiliation: School of Chemistry, University of Nottingham, University Park, Nottingham, UK NG7 2RD.
authors.forename: Qian
authors.initials: Q
authors.lastname: Cao
authors.forename: Caitriona M
authors.initials: CM
authors.lastname: Creely
authors.forename: E Stephen
authors.initials: ES
authors.lastname: Davies
authors.forename: Joanne
authors.initials: J
authors.lastname: Dyer
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Easun
authors.forename: David C
authors.initials: DC
authors.lastname: Grills
authors.forename: David A
authors.initials: DA
authors.lastname: McGovern
authors.forename: Jonathan
authors.initials: J
authors.lastname: McMaster
authors.forename: Jonathan
authors.initials: J
authors.lastname: Pitchford
authors.forename: Jayden A
authors.initials: JA
authors.lastname: Smith
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Sun
authors.forename: John M
authors.initials: JM
authors.lastname: Kelly
authors.forename: Michael W
authors.initials: MW
authors.lastname: George
mesh_terms: D000042:Absorption; D020029:Base Pairing; D056831:Coordination Complexes / Q000737:chemistry*; D004579:Electron Transport; D007364:Intercalating Agents / Q000737:chemistry*; D010619:Phenazines / Q000737:chemistry*; D011067:Poly dA-dT / Q000737:chemistry*; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D011789:Quantum Theory; D012211:Rhenium / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D056831:Coordination Complexes; D007364:Intercalating Agents; D010619:Phenazines; D011089:Polydeoxyribonucleotides; D011067:Poly dA-dT; C019530:poly(dC-dG); D012211:Rhenium