Light-absorbing antenna

An extension of this kind of antennae is a first-generation heterometallic den-drimer with appended organic chromophores like pyrenyl units [25,26]. In the tetranuclear species consisting of an Os(II)-based core surrounded by three Ru(II)-based moieties and six pyrenyl units in the periphery, 100% efficient energy transfer is observed to the Os(II) core regardless of the light-absorbing unit. 

Figure 12.1. Schematic diagram of a photosynthesis reaction center. Light is absorbed by pigments in the light-gathering antenna and absorbed energy is transferred to a photochemically active site P, where it is utilized to initiate photosynthetic reactions.

Nonradiative energy transfer has a major role in the process of photosynthesis. Light is absorbed by large numbers of chlorophyll molecules in light-harvesting antennae and energy is transferred in a stepwise manner to photosynthetic reaction centres, at which photochemical reactions occur. This fundamental energy-transfer process will be considered in more detail in Chapter 12. 

Fig. 2.2 Light-absorbing molecules in Phyconerythrin 545 (PE545) light-arvesting antenna from cryptophyte alage Rhodomonas CS24. Typical interchromophore (centre-to-centre) separation are...

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