Effect of Charge Distribution over a Chlorophyll Dimer on the Redox Potential of P680 in Photosystem II As Studied by Density Functional Theory Calculations†

Biochemistry ◽  
2008 ◽  
Vol 47 (24) ◽  
pp. 6289-6291 ◽  
Author(s):  
Ryouta Takahashi ◽  
Koji Hasegawa ◽  
Takumi Noguchi
Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 187
Author(s):  
Piotr Niemiec ◽  
Renata Tokarz-Sobieraj ◽  
Małgorzata Witko

Density functional theory calculations were carried out to investigate the electronic structures of Keggin-typed [XMo12O40]n− and [XW12O40]n− anions with different heteroatoms (X = Zn2+, B3+, Al3+, Ga3+, Si4+, Ge4+, P5+, As5+, and S6+). The influence of solvent on redox properties of heteropolyanions was discussed. For [XW12O40]n− systems two linear correlation: first, between the experimental redox potential and energies of LUMO orbital; and second, between the experimental redox potential and total energy interaction (calculated between internal tetrahedron (XO4n−), and rest of Kegging anion skeleton, (W12O36)) were designated. Taking into account the similarity of XW12O40n− and XMo12O40n− systems (in geometry and electronic structure), the estimated redox potential of molybdenum heteropolyanions (with X being p block elements) in different solvent were proposed.


RSC Advances ◽  
2014 ◽  
Vol 4 (73) ◽  
pp. 38551-38557 ◽  
Author(s):  
Baotao Kang ◽  
Hu Shi ◽  
Shihai Yan ◽  
Jin Yong Lee

Density functional theory calculations have been carried out for the ground state (S0) and the first excited state (S1) of the H-bonded phenol and imidazole complex as a model system for the active site of photosystem II.


2019 ◽  
Author(s):  
Martin D. Peeks ◽  
Michael Jirasek ◽  
Timothy D. W. Claridge ◽  
Harry L. Anderson

Doping, through oxidation or reduction, is often used to modify the properties of π-conjugated oligomers. In most cases, the resulting charge distribution is difficult to determine. If the oligomer is cyclic and doping establishes global aromaticity or antiaromaticity, then it is certain that the charge is fully delocalized over the entire perimeter of the ring. Here we show that reduction of a six-porphyrin nanoring using decamethylcobaltocene results in global aromaticity (in the 6– state; [90 π]) and antiaromaticity (in the 4– state; [88 π]), consistent with Hückel’s rules. Aromaticity is assigned by NMR spectroscopy and density-functional theory calculations. <br>


2019 ◽  
Author(s):  
Martin D. Peeks ◽  
Michael Jirasek ◽  
Timothy D. W. Claridge ◽  
Harry L. Anderson

Doping, through oxidation or reduction, is often used to modify the properties of π-conjugated oligomers. In most cases, the resulting charge distribution is difficult to determine. If the oligomer is cyclic and doping establishes global aromaticity or antiaromaticity, then it is certain that the charge is fully delocalized over the entire perimeter of the ring. Here we show that reduction of a six-porphyrin nanoring using decamethylcobaltocene results in global aromaticity (in the 6– state; [90 π]) and antiaromaticity (in the 4– state; [88 π]), consistent with Hückel’s rules. Aromaticity is assigned by NMR spectroscopy and density-functional theory calculations. <br>


2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.


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