Wolfgang Kuehnle

Electron transfer and manetic field effects in donor acceptor systems linked by a hydrocarbon chain incorporating phenyl groups

Fluorescence quenching experiments and studies of the spin dynamics in intramolecular radical ion pairs are presented. Compounds investigated are bichromophoric molecules containing 1-pyrenyl (Py) and 4-N,N-dimethylaminophenyl (DMA), linked by a hydrocarbon chain incorporating phenyl groups ( ). The results demonstrate the participation of the aromatic spacers in the primary electron transfer process. Such a spacer-moleculeassisted mechanism, however, seems to be absent in the recombination reaction (return electron transfer) of the radical ion pair. Hyperfine-driven spin mixing, leading to a magnetic field effect in the triplet and exciplex yields, has only been observed with the compound with a longer chain, namely Py—CH2 — —(CH2)2