Pair-delocalization in trigonal mixed-valence clusters: new insight into the vibronic origin of broken-symmetry ground states

2019 ◽  
Vol 21 (21) ◽  
pp. 11122-11131
Author(s):  
Andrew Palii ◽  
Boris Tsukerblat
Keyword(s):  
Mixed Valence ◽  
Ground States ◽  
Electronic States ◽  
Broken Symmetry ◽  
Iron Sulfur ◽  
Insight Into

A new vibronic mechanism for the stabilization of pair-delocalized electronic states in trigonal trimeric mixed valence complexes (such as iron–sulfur [Fe3S4]0 proteins) is proposed.

Insight into the Spin‐Vibronic Problem of a Mixed Valence Magnetic Molecular Cell for Quantum Cellular Automata

ChemPhysChem ◽  
2021 ◽  
Author(s):  
Andrew Palii ◽  
Denis Korchagin ◽  
Sergey Aldoshin ◽  
J. M. Clemente-Juan ◽  
Shmuel Zilberg ◽  
...  
Keyword(s):  
Cellular Automata ◽  
Mixed Valence ◽  
Quantum Cellular Automata ◽  
Insight Into

scholarly journals Using a Chemical Genetic Screen to Enhance Our Understanding of the Antimicrobial Properties of Gallium against Escherichia coli

Genes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 34 ◽  
Author(s):  
Natalie Gugala ◽  
Kate Chatfield-Reed ◽  
Raymond J. Turner ◽  
Gordon Chua
Keyword(s):  
Escherichia Coli ◽  
Cell Envelope ◽  
Antimicrobial Properties ◽  
Iron Sulfur Cluster ◽  
Nucleotide Biosynthesis ◽  
E Coli ◽  
Chemical Genetic ◽  
Iron Sulfur ◽  
Insight Into ◽  
Mutant Collection

The diagnostic and therapeutic agent gallium offers multiple clinical and commercial uses including the treatment of cancer and the localization of tumors, among others. Further, this metal has been proven to be an effective antimicrobial agent against a number of microbes. Despite the latter, the fundamental mechanisms of gallium action have yet to be fully identified and understood. To further the development of this antimicrobial, it is imperative that we understand the mechanisms by which gallium interacts with cells. As a result, we screened the Escherichia coli Keio mutant collection as a means of identifying the genes that are implicated in prolonged gallium toxicity or resistance and mapped their biological processes to their respective cellular system. We discovered that the deletion of genes functioning in response to oxidative stress, DNA or iron–sulfur cluster repair, and nucleotide biosynthesis were sensitive to gallium, while Ga resistance comprised of genes involved in iron/siderophore import, amino acid biosynthesis and cell envelope maintenance. Altogether, our explanations of these findings offer further insight into the mechanisms of gallium toxicity and resistance in E. coli.

scholarly journals Mechanistic insight into proton-coupled mixed valency

2016 ◽  
Vol 52 (1) ◽  
pp. 100-103 ◽  
Author(s):  
Luke A. Wilkinson ◽  
Kevin B. Vincent ◽  
Anthony J. H. M. Meijer ◽  
Nathan J. Patmore
Keyword(s):  
Electron Transfer ◽  
Valence State ◽  
Mixed Valence ◽  
Bridging Ligands ◽  
Mixed Valency ◽  
Mixed Valence State ◽  
Mechanistic Insight ◽  
Insight Into

Stabilisation of the mixed-valence state in [Mo2(TiPB)3(HDOP)]2+ (HTiPB = 2,4,6-triisopropylbenzoic acid, H2DOP = 3,6-dihydroxypyridazine) by electron transfer (ET) is related to the proton coordinate of the bridging ligands.

Validation of broken-symmetry density functional methods for the calculation of electron paramagnetic resonance parameters of dinuclear mixed-valence MnIVMnIII complexes

2009 ◽  
Vol 87 (10) ◽  
pp. 1521-1539 ◽  
Author(s):  
Sandra Schinzel ◽  
Martin Kaupp
Keyword(s):  
Density Functional ◽  
Mixed Valence ◽  
Broken Symmetry ◽  
Dft Methods ◽  
Paramagnetic Resonance ◽  
Wide Range ◽  
B3lyp Calculations ◽  
Epr Parameters ◽  
Exact Exchange ◽  
Hyperfine Couplings

. The EPR parameters of a series of dinuclear manganese(III,IV) complexes with mono(μ-oxo), bis(μ-oxo), (μ-oxo)(μ-carboxylato), bis(μ-oxo)(μ-carboxylato), and (μ-oxo)bis(μ-carboxylato) bridges were studied by broken-symmetry density functional (DFT) methods. The influence of the exchange-correlation functional on the agreement with experiment has been evaluated systematically for g tensors; 55Mn, 14N, and 1H hyperfine coupling tensors; and Heisenberg exchange couplings. 14N and 1H hyperfine couplings, 55Mn hyperfine anisotropies, g tensors, and exchange couplings are well described by hybrid functionals with moderate exact-exchange admixtures such as B3LYP. The isotropic 55Mn hyperfine couplings require larger exact-exchange admixtures. However, the errors of the B3LYP calculations are systematic and may be corrected by a constant scaling factor, providing good predictive power for a wide range of EPR parameters with broken-symmetry DFT and standard functionals. The influence of terminal and bridging ligands on structure, spin-density distributions, and EPR parameters are evaluated systematically. Computed hyperfine and g tensors are not covariant to each other. This may have consequences for spectra simulations. The nature of the broken-symmetry state and the origin of its spin contamination were analyzed by an expansion into restricted determinants, based on paired orbitals.

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