Photoinduced electron transfer in a rigid first generation triphenylamine core dendrimer substituted with a peryleneimide acceptor.
The electron-transfer process of a first generation dendrimer with a triphenylamine core substituted with one peryleneimide chromophore at the rim (N1P1) was investigated by steady-state and time-resolved spectroscopic techniques in two different solvents of medium and low polarity. Single photon counting experiments showed a fast charge separation and a thermally activated back reaction, which is uncommon for a polyaryl bridge or long-distance through-space electron transfer. The four exponential fluorescence decay can be traced to the presence of two subsets of molecules, which are constitutional isomers of N1P1. Although formally N1P1 resembles a donor-bridge-acceptor compound, detailed analysis of the data shows that the electron transfer occurs by a through-space mechanism. This amine core dendrimer has peculiar and unique characteristics resulting in the observation of efficient back transfer and delayed peryleneimide fluorescence in diethyl ether at 293 K and very long-lived charge recombination luminescence at 77 K.
Lor
Marc
M
Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium.
Thielemans
Jan
J
Viaene
Lucien
L
Cotlet
Mircea
M
Hofkens
Johan
J
Weil
Tanja
T
Hampel
Christine
C
Müllen
Klaus
K
Verhoeven
Jan W
JW
Van Der Auweraer
Mark
M
De Schryver
Frans C
FC