Mimicry of the natural photosynthetic reaction centre has been a very active research area in recent years due to the possibility of achieving improved efficiencies in solar energy conversion devices. The high efficiency of the natural system is due to the multi-step electron sequence. Donor-bridge-acceptor triads are the most common approach in the mimicking of the multi-step electron transfer sequence.1

Porphyrins are often used in artificial photosynthetic system as they are similar to the natural chromophores; in particular, they contain an extensive conjugated π-system that is suitable for efficient electron transfer.2 The incorporation of fullerene as an electron-acceptor is widespread because of its symmetrical shape, large size and π-electron system,3 while ferrocene is a stable electron donor that is often used as a reference in electrochemical experiments owing to its simplicity and regularity.4

The ferrocene-porphyrin-fullerene systems using short conjugated imidazole linkages, such as 1 and 2 and other extended systems, were synthesised. Their photochemistry observed using picosecond and microsecond transient absorption spectroscopy supported by electrochemical measurements and density-functional theory calculations. This study is made to test the hypothesis that the observed long charge separated state arises as a consequence of anionic charge delocalization between the ferrocene and its conjugated porphyrin in the final charge-separated state. The prediction made based on theses model that small changes in the system such as those associated with regioisomerisation can significantly effect the charge delocalization and consequently the charge-recombination rate.