Photosynthesis artificial systems

Photochemical fixation of carbon dioxide is a function of green plants and some bacteria in nature in the form of photosynthesis. All living organisms on the Earth are indebted directly or indirectly to photosynthesis. Thus, many attempts have been made to simulate the photosynthetic system and make artificial systems, although to date very little success has been achieved. 

Much has been written about artifical solar-energy converters - the reader is referred to references 10, 12, 14-17 for detailed treatments. Here I shall deal exclusively with those artificial systems designed to mimic various aspects of the photosynthesis reaction. 

Photoinduced electron transfer (PET) is often responsible for fluorescence quenching. This process is involved in many organic photochemical reactions. It plays a major role in photosynthesis and in artificial systems for the conversion of solar energy based on photoinduced charge separation. Fluorescence quenching experiments provide a useful insight into the electron transfer processes occurring in these systems. 

Photochemical conversion of solar energy in artificial systems (as in natural photosynthesis) is essentially based on electron-transfer between an excited photosensitizer (A ) and an appropriate electron acceptor (B)... 

The philosophy of membrane-mimetic chemistry may be illustrated by a comparison of plant photosynthesis with sacrificial water photoreduction in artificial systems the process has been mediated by metal-catalyst-coated semiconductor colloids supported on polymerized vesicles (Fig. 4a) [59-64]. 

Shi, D.J., Hall, D.O. and Tang, P.S. 1987a. Photosynthesis, Nitrogen fixation, Ammonia photoproduction and structure of Anabaena azollae immobilized in natural and artificial systems. In Progress in Photosynthesis research (Ed. J. Biggens), vol. II. Martinus NijhoffPubs., Dordrecht, pp.641-644. 

Photophysical processes are commonly encountered and can participate in such important phenomena as energy harvesting (antenna effect), which is the basis for natural photosynthesis and artificial systems mimicking it [4-21] (see below). 

Detailed studies of the molecular mechanism of natural photosynthesis to create artificial systems that mimic some of the remarkable traits of natural ones (i.e.,... 

The fact that the pKa of the various oxidation states of quinones differ dramatically has been exploited in a recent design of artificial systems that mimic the light-driven transmembrane proton transport characteristic of natural photosynthesis [218]. Triad artificial reaction centers structurally related to 41 were vectorially inserted into the phospholipid bilayer of a liposome (vesicle) such that the majority of the quinone moieties are near the external surface of the membrane, and the majority of the carotenoids extend inward, toward the interior surface. The membrane... 

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