Silicon-Phthalocyanine-Cored Fullerene Dendrimers: Synthesis and Prolonged Charge-Separated States with Dendrimer Generations

Silicon‐phthalocyanine‐cored fullerodendrimers with up to eight fullerene substituents (SiPc–n C60; n=2, 4, and 8) have been synthesized. Photophysical properties of newly synthesized SiPc–n C60 have been investigated by time‐resolved fluorescence and transient absorption analysis with pulsed laser light. Laser photolysis measurements suggest the occurrence of a charge‐separation process from 1SiPc* to the C60 subunits. The nanosecond transient absorption spectra in the near‐IR region indicate that the lifetimes of the formed radical ion pairs are prolonged on the order of SiPc–8 C60>SiPc–4 C60>SiPc–2 C60, which may be related to the electron migration among the C60 subunits. The usefulness of SiPc–n C60 as light‐harvesting systems, evaluated as a ratio of the rates of charge recombination to those of charge separation, increases markedly with the dendrimer generation. Improving with age: Silicon‐phthalocyanine‐cored fullerodendrimers with up to eight fullerene substituents (SiPc–n C60; n=2, 4, and 8; see picture) were synthesized. Laser photolysis measurements suggest the occurrence of a charge‐separation process from the 1SiPc* to the C60 subunits. The usefulness of SiPc–n C60 as light‐harvesting systems increases markedly with the dendrimer generation.