Assemblies of artificial photosynthetic reaction centres

Nature harnesses solar energy for photosynthesis in which one reaction centre is associated with a number of light harvesting units. The reaction centre and light-harvesting units are assembled by non-covalent interactions such as hydrogen bonding and pi-pi interactions. This article presents various strategies to assemble artificial photosynthetic reaction centres composed of multiple light harvesting units and charge-separation units, which are connected by non-covalent bonding as well as covalent bonding. First light-harvesting units are assembled on alkanethiolate-monolayer-protected metal nanoparticles (MNPs), which are connected with electron acceptors by non-covalent bonding. Light-harvesting units can also be assembled using dendrimers and oligopeptides to combine with electron acceptors by pi-pi interactions. The cup-shaped nanocarbons generated by the electron-transfer reduction of cup-stacked carbon nanotubes have been functionalized with a number of porphyrins acting as light-harvesting units as well as electron donors. In each case, the photodynamics of assemblies of artificial photosynthetic reaction centres have revealed efficient energy transfer and electron transfer to afford long-lived charge-separated states.