Photosynthetic artificial

Figure C3.2.17. Diagram of a liposome-based artificial photosynthetic membrane showing the photocycle that pumps protons into the interior of the liposome and the CFqF j-ATP synthase enzyme. From [55],...

Steinberg-Yfrach G, Rigaud G-L, Durantini E N, Moore A L, Gust D and Moore T A 1998 Light driven production of ATP catalysed by F0F1-ATP synthase in an artificial photosynthetic membrane Nature 392 479-82... 

New natural polymers based on synthesis from renewable resources, improved recyclability based on retrosynthesis to reusable precursors, and molecular suicide switches to initiate biodegradation on demand are the exciting areas in polymer science. In the area of biomolecular materials, new materials for implants with improved durability and biocompatibility, light-harvesting materials based on biomimicry of photosynthetic systems, and biosensors for analysis and artificial enzymes for bioremediation will present the breakthrough opportunities. Finally, in the field of electronics and photonics, the new challenges are molecular switches, transistors, and other electronic components molecular photoad-dressable memory devices and ferroelectrics and ferromagnets based on nonmetals. 

WiUner, I., and Willner, B. Artificial Photosynthetic Model Systems Using Light-Induced Electron Transfer Reactions in Catalytic and Biocatalytic Assemblies. 159,153-218 (1991). 

Kodis, G., C. Herrero, R. Palacios, E. Marino-Ochoa, S. Gould, L. de la Garza, R. van Grondelle, D. Gust, T. A. Moore, A. L. Moore, and J. T. M. Kennis. 2004. Light harvesting and photoprotective functions of carotenoids in compact artificial photosynthetic antenna designs. J. Phys. Chem. B 108 414-425. 

From a fundamental viewpoint, carbon dioxide reduction is a model reaction which can help us to understand better the mechanism of natural photosynthesis.11 Development of artificial photosynthetic systems, by mimicking functions of green plants, is one of... 

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. 

Tazuke and Kitamura162 reported the first example of an artificial photosynthetic system based on electron transport sensitization, although the product was not a hydrocarbon, but rather formic acid. Their system is shown schematically in Fig. 17. In this system, the photochemically generated singlet excited state of an aromatic hydrocarbon, such as pyren (Py) or perylene (Pe), was... 

Figure 17. Schematic representation of an artificial photosynthetic system.162...

Fig.4.30 Immobilization ofthe bacterial photosynthetic reaction center on tailored three-dimensional wormlike mesoporous W03-Ti02 films for artificial photosynthetic systems (A) procedure of film coating (B) proposed scheme of photoelectric conversion. Reprinted with permission from [229], Y. Lu et at., Langmuir 2005, 21, 4071. 2005, American Chemical Society.

Warwel, S., Sojka, M., and Riisch, M. Synthesis of Dicarboxylic Acids by Transition-Metal Catalyzed Oxidative Cleavage of Terminal-Unsaturated Fatty Acids. 164, 79-98 (1993). Willner, I., and Willner, B. Artificial Photosynthetic Model Systems Using Light-Induced Electron Transfer Reactions in Catalytic and Biocatalytic Assemblies. 159, 153-218 (1991). 

Another important area is the use of photochemistry—chemistry that results from light absorption—to perform transformations that are not otherwise possible. The practical applications of photosynthesis were based on fundamental work to learn the new pathways that light absorption makes possible, but the work on these synthetic methods has also added to our basic understanding of the reaction mechanisms. The important natural process of photosynthesis also inspires some work in photochemistry, where the challenge is one of producing artificial photosynthetic systems that could use sunlight to drive the formation of energetic materials. 

Tributsch, H. Pohlmann, L. 1995. Synergetic molecular approaches towards artificial and photosynthetic water photoelectrolysis. J. Electroanal. Chem. 396 53-61. 

Dutta, P.K. and Ledney, M. (1997). Charge-transfer processes in zeolites toward better artificial photosynthetic models. In Molecular Level Artificial Photosynthetic Materials, Meyer, G.J. (ed.), Vol. 44, pp. 209-271. John Wiley Sons, New York... 

Figure 1. Schematic representation of the artificial photosynthetic reaction center by a monolayer assembly by A-S-D triad and antenna molecules for light harvesting (H), lateral energy migration and energy transfer, and charge separation across the membrane via multistep electron transfer (a) Side view of mono-layer assembly, (b) top view of a triad surrounded by H molecules, and (c) energy diagram for photo-electric conversion in a monolayer assembly.

In the present review, first we will describe how to fabricate artificial photosynthetic reaction center in nanometer scales by making use of phase separation in mixed monolayers of hydrocarbon (HC) and fluorocarbon (FC) amphiphiles [2,5,20-26] as shown in Fig. 2b [3]. The phase separated structures were studied by SPMs such as AFM, SSPM, and scanning near-field optical/atomic force microscopy (SNOAM) [27-33] as well as a conventional local surface analysis by SIMS [3,5], The model anionic and cationic HC amphiphilic... 

Figure 4. Detection of the change in photo-induced surface dipole moments in highly oriented A-S-D triads in artificial photosynthetic reaction centers as the local surface potential change in nano-domains measured by SSPM.

G. Steinberg-Yfrach, P. A. Liddell, S. C. Hung, A. L Moore, D. Gust, T. A. Moore, Conversion of Light Energy to Proton Potential in Liposomes by Artificial Photosynthetic Reaction Centres , Nature 1997,385,239-241. 

There have been many attempts to mimic some features of photosynthesis with abiotic systems for purposes of artificial solar energy conversion. Ideally a fuel, e.g., H2, is formed through a photosynthetic process. Photolysis of water is a highly endergonic process ... 

Explosive research activity is going on in micellar photochemistry. This is related to the development of artificial photosynthetic systems, and the anisotropic nature of globular micelles and bilayer membranes is used for conservation of excitation energy. The subject has been recently reviewed (Kalyanasundaram, 1978). 

Explain how efforts have been made to develop artificial photosynthetic systems. Understand the difficulties and potential benefits of such systems. 

In artificial photosynthetic models, porphyrin building blocks are used as sensitisers and as electron donors while fullerenes are used as electron acceptors. Triads, tetrads, pentads and hexads containing porphyrins and Qo have been reported in the literature (see the Further Reading section). 

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