| Abstract
| - A novel supramolecular electron donor−acceptor hybrid (1) has been designed through axialcoordination of a perylenebisimide moiety [BPyPDI], bearing two 4-pyridyl substituents at the imido positions,to the ruthenium(II) metal centers of two phthalocyanines [Ru(CO)Pc]. This modular protocol enables accessto electron donor−acceptor hybrids with potentially great design flexibility. The new array (1) has beencharacterized by standard spectroscopic methods, and its photophysical behavior has been establishedby using ultrafast and fast time-resolved techniques. Photoexcitation of either chromophore leads to aproduct that is essentially identical for both pathways, that is, evolving from the [Ru(CO)Pc] or [BPyPDI]singlet excited state. Features of the photoproduct are new transient maxima at 530 and 725 nm, plustransient minima at 580 nm and 650 nm. Based on the radiolytically generated [BPyPDI•-] (i.e., one-electronreduction of [BPyPDI]) and [Ru(CO)Pc•+] (i.e., one-electron oxidation of [Ru(CO)Pc]) features, which inthe 300 and 900 nm range remarkably resemble those noted for photoexcited 1, we attribute the photolyticallygenerated species to the composite spectrum of the [Ru(CO)Pc•+−BPyPDI•-−RuCOPc] radical ion pairstate. Its lifetime, which is on the order of 115 ± 5 ns, reveals a significant stabilization and confirms thatthe strongly exothermic charge recombination dynamics are placed deeply in the inverted region of theMarcus parabola.
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