Synthesis of Quinone-linked Porphyrin Dimer, Trimer, and Tetramer As Models for Photosynthetic Reaction Center

1991 ◽  
Vol 20 (3) ◽  
pp. 481-484 ◽  
Author(s):  
Atsuhiro Osuka ◽  
Toshi Nagata ◽  
Kazuhiro Maruyama
Keyword(s):  
Reaction Center ◽  
Photosynthetic Reaction Center ◽  
Porphyrin Dimer

Co-facial magnesium porphyrin dimer complexed with fullerene: photosynthetic reaction center model of 'special pair' self-assembled to electron acceptor

2008 ◽  
Vol 12 (07) ◽  
pp. 857-865 ◽  
Author(s):  
Atula S. D. Sandanayaka ◽  
Navaneetha K. Subbaiyan ◽  
Raghu Chitta ◽  
Yasuyuki Araki ◽  
Osamu Ito ◽  
...  
Keyword(s):  
Reaction Center ◽  
Electron Acceptor ◽  
Photosynthetic Reaction Center ◽  
Ammonium Cation ◽  
Model Systems ◽  
Spectral Studies ◽  
Special Pair ◽  
Self Assembled ◽  
Alkyl Ammonium ◽  
Porphyrin Dimer

Using a self-assembled supramolecular approach, a closer model for the photosynthetic reaction center 'special pair' assembled with an electron acceptor conjugate, is reported. As the 'special pair' donor, magnesium meso-(benzo-15-crown-5)porphyrin was self-assembled with K + to form a highly stable Mg porphyrin dimer with a co-facial geometry arrangement, which is a better electron donor since it is nearly 130 mV easier to oxidize compared to the earlier reported Zn porphyrin dimer analog. Further, pyridine and alkyl ammonium cation-functionalized fullerene was attached via axial coordination and crown ether-alkyl ammonium cation complexation to form the four-fold, donor-acceptor complex. The self-assembled supramolecular complex, constructed using this approach, possesses defined geometry and orientation. Efficient charge separation from the singlet excited state of the Mg porphyrin dimer to the fullerene entity and a relatively slow charge recombination, were revealed by time-resolved emission and nanosecond transient absorption spectral studies, supporting the impending exploitation of these novel biomimetic model systems for light energy harvesting applications.

Computational Investigation of the Asymmetry in Photosynthetic Reaction Center Models from First Principles

2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Johannes Neugebauer
Keyword(s):  
Spin Density ◽  
Reaction Center ◽  
Density Functional ◽  
Photosynthetic Reaction Center ◽  
Chem Phys ◽  
Molecular Structures ◽  
Error Characteristic ◽  
Molecular Systems ◽  
Density Distributions ◽  
The Asymmetry

We present a computational analysis of the asymmetry in reaction center models of photosystem I, photosystem II, and bacteria from <i>Synechococcus elongatus</i>, <i>Thermococcus vulcanus</i>, and <i>Rhodobacter sphaeroides</i>, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from dimeric models in vacuum to large protein including up to about 2000 atoms. The calculated spin densities showed a good agreement with available experimental results and were used to validate reaction center models reported in the literature. We demonstrated that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.

A Comparison of Stigmatellin Conformations, Free and Bound to the Photosynthetic Reaction Center and the Cytochrome bc1 Complex

2007 ◽  
Vol 368 (1) ◽  
pp. 197-208 ◽  
Author(s):  
C. Roy D. Lancaster ◽  
Carola Hunte ◽  
Jack Kelley ◽  
Bernard L. Trumpower ◽  
Robert Ditchfield
Keyword(s):  
Reaction Center ◽  
Photosynthetic Reaction Center ◽  
Cytochrome Bc1 ◽  
Bc1 Complex ◽  
Cytochrome Bc1 Complex
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