The transient species formed following excitation of fac-[Re(CO) 3(F2dppz)(py)]+ (F2dppz = 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.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry