Photoinduced electron transfer in a β,β′-pyrrolic fused ferrocene-(zinc porphyrin)-fullerene

A donor-acceptor linked triad with a short spacer (Fc-ZnP-C₆₀) 1 was designed and synthesised to attain the longest charge-separation lifetime, 630 μs, ever reported for triads at room temperature. The ferrocene electron donor and fullerene electron acceptor of triad 1 are attached to imidazole rings fused to opposite β,β′-pyrrolic positions of the zinc porphyrin. After excitation of the porphyrin, electron transfer to C ₆₀ occurs within 230 ps, followed by hole transfer to ferrocene after 500 ps to produce the long-lived charge-separated state.