Antenna mimics

R. Takahashi, Y. Kobuke, Hexameric Macroring of Gable-Porphyrins as a Light-Harvesting Antenna Mimic , J. Am. Chem. Soc., 125,2372 (2003)... 

Takahashi, R. Kobuke. Y. Hexameric macroring of gable-porphyrins as a light-harvesting antenna mimic. J. Am. Chem. Soc. 2003. 125, 2372-2373. 

Takahashi R, Kobuke Y. Hexametic macroting of gable-porphyrins as a hght-harvesting antenna mimic. Jrim Chem Soc. 2003 125 2372-2373. 

Li and coworkers49 reported a molecular motion of /1-carotene and a carotenopor-phyrin dyad (composed of a porphyrin, a trimethylene bridge and a carotenoid polyene) in solution. Internal rotational motions in carotenoid polyenes and porphyrins are of interest because they can mediate energy and electron transfer between these two moieties when the pigments are joined by covalent bonds. Such internal motions can affect the performance of synthetic model systems which mimic photosynthetic antenna function,... 

The study of artificial photosynthesis has been the subject of ongoing attention for many years now due to the need for sustainable energy resources. In natural photosynthesis a lightharvesting antenna system with a large optical cross-section (for example the LH2 complex) absorbs a photon that is funneled by energy transfer (ET) to the reaction centre [1-3]. Excellent candidates to mimic the natural antenna system are molecules that efficiently absorb light and are able to transfer the captured energy to other parts of the molecule. Molecules based on Zn and free-base porphyrins are examples of compounds that can be used as models for the LID complex [4]. 

These two molecules were the antecedents of a variety of oligomeric porphyrin and chlorophyll derivatives which were constructed as mimics of the reaction center special pair. Many of these systems exhibit interesting optical properties which allow modelling of the electronic interactions within the special pair and/or the antenna function of chlorophyll, which involves singlet-singlet energy transfer... 

Wasielewski then focused on a particular ring structure found in antenna proteins to see how a system could be developed based on chlorophyll that mimics some of these features. It turns out that the spectral shift does not explain anything. He said that there needs to be a structural tool to present specific information. The Advanced Photon Source, the brightest X-ray source in the country, at Argonne National Laboratory, is currently being used for this purpose. 

We shall begin with a brief description of natural photosynthetic electron transfer, and then discuss some of the simplest man-made devices which attempt to mimic this process. We shall see how these devices have evolved into more complicated molecular constructions which are much more successful. The preparation and study of synthetic species which mimic photosynthetic antenna function will then be reviewed. Finally, model systems which have provided insight into the process whereby carotenoid... 

Thus, chlorophyll-based triad species can also successfully mimic the multistep strategy of natural photosynthesis to yield long-lived, energetic charge-separated states. Triad 13 and related molecules also mimic carotenoid photoprotection from singlet oxygen and carotenoid antenna function. These aspects of the molecules will be discussed in later sections. 

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