Molecular mimicry of photosynthetic energy and electron transfer

Journal Article · Wed Mar 31 23:00:00 EST 1993 · Accounts of Chemical Research; (United States)

DOI:https://doi.org/10.1021/ar00028a010· OSTI ID:6098258

Gust, D; Moore, T A; Moore, A L ^[1]

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1. Arizona State Univ., Tempe (United States)

Proper application of reaction design considerations can yield artificial photosynthetic devices which credibility mimic the three natural photochemical processes. One approach is to use pigments and electron donors and acceptors related to those found in natural photosynthesis (and thus presumably optimal for that system), but to replace the protein with covalent bonds as an organizing precept. Molecular pentads described herein exemplify the success of this approach. At the heart of these molecules, are two covalently linked synthetic porphyrin moieties (P-P). One of these models for chlorophyll is attached to a carotenoid polyene (C), whereas the other is linked to a rigid diquinone (Q-Q). As discussed later in this paper, excitation of such a pentad is followed by photoinitiated electron transfer steps which ultimately give a C[sup [center dot]+]-P-P-Q-Q[sup [center dot]-] charge-separated state. Depending upon the structure of the pentad and the conditions, these states are formed with quantum yields of up to 0.83, have lifetimes approaching 0.5 ms, and store about one-half of the energy of the exciting singlet state. Related photosynthesis mimics display singlet-singlet energy transfer from carotenoid polyenes to porphyrins and among porphyrin chromophores, and rapid quenching of porphyrin triplet states by attached carotenoids. How have the structures of these and other successful artificial reaction centers evolved, and what will be the next steps in their development The authors will address these questions from the point of view of photoinitiated electron transfer, and then singlet and triplet energy transfer will briefly be considered. 37 refs., 4 figs.

• OSTI ID: 6098258
• Journal Information: Accounts of Chemical Research; (United States), Journal Name: Accounts of Chemical Research; (United States) Vol. 26:4; ISSN 0001-4842; ISSN ACHRE4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
AROMATICS
BIOMIMETIC PROCESSES
CARBOXYLIC ACIDS
CAROTENOIDS
CHEMICAL REACTIONS
CHEMISTRY
CHLOROPHYLL
ELECTRON TRANSFER
ENERGY TRANSFER
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOSYNTHESIS
PHYTOCHROMES
PIGMENTS
POLYENES
PORPHYRINS
PROTEINS
QUINONES
SYNTHESIS
TERPENES