Photoinduced intermolecular electron transfer and energy transfer of C60 dendrimers

Abstract

Photoinduced intermolecular electron-transfer and energy-transfer processes of the fullerodendrimers with two poly(amidoamine) dendron groups of 0.5-th, 1.5-th and 2.5-th generations have been investigated by laser flash photolysis. The rate constants and quantum yields of photoinduced electron transfer with the added aromatic amine donors in PhCN tend to decrease with the dendron generation, indicating that the bulky dendron groups act as barriers for the donor molecules to approach the C 60 moiety in the center of the dendrimers. The decreases in the rate constants of triplet energy transfer processes vs. O 2 and β-carotene with the dendron generation are smaller than those of electron-transfer process, probably because effective encounter radii for energy transfer are larger than those for electron transfer; hence, less sensitive to dendrimer generation. A kinetic model for intermolecular electrontransfer and energy-transfer of fullerodendrimers was proposed.

Dendritic Architectures for Design of Photo– and Spin–Functional Nanomaterials

“…Other than porphyrin derivatives as electron-donating components, a variety of dendritic systems for photoinduced electron transfer reaction have been reported using amine, cytochrome c, and phenanthlorine copper(I) complex as electron donors. [74][75][76][77][78][79] Utilization of the dendrimer framework to encapsulate acceptor moieties c.f. viologen 80,81 and norbornadiene, 82 or donor units such as ruthenium bipyridine complex and anthracene 84 have also been reported for the construction of electron transfer systems.…”