Spin-density distributions in meso-alkyl/aryl hybrid porphyrin cation radicals

1988 ◽  
Vol 27 (8) ◽  
pp. 1510-1512 ◽  
Author(s):  
Michael Atamian ◽  
Richard W. Wagner ◽  
Jonathan S. Lindsey ◽  
David F. Bocian
Keyword(s):  
Spin Density ◽  
Alkyl Aryl ◽  
Cation Radicals ◽  
Density Distributions ◽  
Porphyrin Cation

ChemInform Abstract: Spin-Density Distributions in meso-Alkyl/Aryl Hybrid Porphyrin Cation Radicals

ChemInform ◽  
1988 ◽  
Vol 19 (32) ◽  
Author(s):  
M. ATAMIAN ◽  
R. W. WAGNER ◽  
J. S. LINDSEY ◽  
D. F. BOCIAN
Keyword(s):  
Spin Density ◽  
Alkyl Aryl ◽  
Cation Radicals ◽  
Density Distributions ◽  
Porphyrin Cation

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.

ESR Studies on 205Tl Hyperfine Couplings in the Radical Cations of Tl(III)Porphyrins

1974 ◽  
Vol 29 (12) ◽  
pp. 1827-1833 ◽  
Author(s):  
Chr. Mengersen ◽  
J. Subramanian ◽  
J.-H. Fuhrhop ◽  
K. M. Smith
Keyword(s):  
Spin Density ◽  
Spin Polarization ◽  
Radical Cations ◽  
Esr Spectra ◽  
Cation Radicals ◽  
Bilinear Relation ◽  
Tetraphenyl Porphyrin ◽  
Pi Orbitals ◽  
Spin Densities ◽  
Hyperfine Couplings

The isotropic 205Tl hyperfine couplings obtained from the ESR spectra of the radical cations of Tl (III) meso tetraphenyl porphyrin (TPP), octaethyl porphyrin (OEP) and octaethyl chlorin (OEC) are reported. The radical cations were generated by electrooxidation in dichloromethane as solvent. A Karplus-Fraenkel type bilinear relation is used to interpret the 205Tl couplings, taking into account the sigma-pi spin polarization of Tl -N bonds by the spin density at the nitrogen atoms in the ligand as well as the direct pi interaction of the orbitals of Tl with the pi orbitals of the ligand. It is shown that for the cation radicals of Tl porphyrins, both these mechanisms contribute to the Tl couplings whereas for the cation radicals of Co- and Zn-porphyrins the sigma-pi polarization alone is sufficient to account for the metal hyperfine couplings. It is suggested that Tl-hyperfine couplings can be used to estimate the nitrogen spin densities of porphyrin radical systems when the nitrogen splittings are not resolved in the ESR spectra.

Two phosphaalkene radical cations with inverse spin density distributions

2015 ◽  
Vol 44 (34) ◽  
pp. 15099-15102 ◽  
Author(s):  
Xiaobo Pan ◽  
Xingyong Wang ◽  
Zaichao Zhang ◽  
Xinping Wang
Keyword(s):  
Spin Density ◽  
Radical Cations ◽  
Density Distributions ◽  
Weakly Coordinating ◽  
Weakly Coordinating Anion

Two phosphaalkene radical cations have been made by using a weakly coordinating anion, and they exhibit inverse spin density distributions.

scholarly journals Spin Density Distribution and Energy Stabilization in the Cation Radicals of Multilayered Compounds

1982 ◽  
Vol 55 (6) ◽  
pp. 1782-1789 ◽  
Author(s):  
Hiroaki Ohya-Nishiguchi ◽  
Atsushi Terahara ◽  
Noboru Hirota ◽  
Yoshiteru Sakata ◽  
Soichi Misumi
Keyword(s):  
Density Distribution ◽  
Spin Density ◽  
Spin Density Distribution ◽  
Cation Radicals
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