PHOTOINDUCED LONG-DISTANT SUPEREXCHANGE ELECTRON TRANSFER IN NANOSCALE PORPHYRIN TRIADS WITH COVALENTLY LINKED ACCEPTORS

摘要

Here, we discuss energy relaxation dynamics for nanoscale self-assembled porphyrin triads based on non-covalent two-fold extra-coordination of the porphyrin free-base extra-ligand with Zn-octaethylporphyrin chemical dimer (ZnOEP)_2Ph, (donor, D), while the last, in its turn, may contain covalently linked electron acceptors, quinone, Q or pyromellitimide, Pirn. Based on picosecond time-resolved spectroscopy in solutions and theoretical estimations it has been proven that the deactivation of the dimer excited S_1 state is caused by two competing processes (energy migtation, EM, and photoinduced electron transfer, PET). In contrast, the porphyrin extra-ligand relaxation dynamics is governed by the effective superexchange PET to a spatially separated electron acceptors Q or Pirn, where the dimer (ZnOEP)_2Ph plays the role of quantum bridge.