| Abstract
| - Three rotaxanes, with axles with two zinc porphyrins (ZnPs) at both ends penetrating into a necklace pendinga C60 moiety, were synthesized with varying interlocked structures and axle lengths. The intra-rotaxanephotoinduced electron transfer processes between the spatially positioned C60 and ZnP in rotaxanes wereinvestigated. Charge-separated (CS) states (ZnP•+, C60•-)rotaxane are formed via the excited singlet state of ZnP(1ZnP*) to the C60 moiety in solvents such as benzonitrile, THF, and toluene. The rate constants and quantumyields of charge separation via 1ZnP* decrease with axle length, but they are insensitive to solvent polarity.When the axle becomes long, charge separation takes place via the excited triplet state of ZnP (3ZnP*). Thelifetime of the CS state increases with axle length from 180 to 650 ns at room temperature. The small activationenergies of charge recombination were evaluated by temperature dependence of electron-transfer rate constants,probably reflecting through-space electron transfer in the rotaxane structures.
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