scholarly journals Spectroelectrochemical Properties and Catalytic Activity in Cyclohexane Oxidation of the Hybrid Zr/Hf-Phthalocyaninate-Capped Nickel(II) and Iron(II) tris-Pyridineoximates and Their Precursors

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 336
Author(s):  
Yan Z. Voloshin ◽  
Semyon V. Dudkin ◽  
Svetlana A. Belova ◽  
Daniel Gherca ◽  
Dumitru Samohvalov ◽  
...  
Keyword(s):  
Density Functional ◽  
Redox Activity ◽  
Oxidation Reactions ◽  
Paramagnetic Resonance ◽  
Molecular Systems ◽  
Near Ir ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies ◽  
Electron Paramagnetic

The in situ spectroelectrochemical cyclic voltammetric studies of the antimony-monocapped nickel(II) and iron(II) tris-pyridineoximates with a labile triethylantimony cross-linking group and Zr(IV)/Hf(IV) phthalocyaninate complexes were performed in order to understand the nature of the redox events in the molecules of heterodinuclear zirconium(IV) and hafnium(IV) phthalocyaninate-capped derivatives. Electronic structures of their 1e-oxidized and 1e-electron-reduced forms were experimentally studied by electron paramagnetic resonance (EPR) spectroscopy and UV−vis−near-IR spectroelectrochemical experiments and supported by density functional theory (DFT) calculations. The investigated hybrid molecular systems that combine a transition metal (pseudo)clathrochelate and a Zr/Hf-phthalocyaninate moiety exhibit quite rich redox activity both in the cathodic and in the anodic region. These binuclear compounds and their precursors were tested as potential catalysts in oxidation reactions of cyclohexane and the results are discussed.

Structural and spectropscopic studies of a three-dimensional hydrogen-bonded copper(II) complex: aqua[bis(pyridin-2-ylcarbonyl)amidato]cyanidocopper(II)

2015 ◽  
Vol 71 (2) ◽  
pp. 165-168 ◽  
Author(s):  
Jiang-Yun Wang
Keyword(s):  
Three Dimensional ◽  
Spectroscopic Studies ◽  
Epr Spectrum ◽  
Cyclic Voltammetric ◽  
Paramagnetic Resonance ◽  
Irreversible Oxidation ◽  
Square Planar ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies ◽  
Electron Paramagnetic

The preparation and X-ray and spectroscopic studies of the title copper(II) complex, [Cu(C12H8N3O2)(CN)(H2O)], are reported. The CuIIcation is five-coordinated, forming a distorted square-planar pyramid with an Addison τ parameter of 0.14. The UV–vis spectrum shows ad–dtransition of the CuIIcentre at 638 nm, and the electron paramagnetic resonance (EPR) spectrum confirms that the CuIIcation has an axial symmetry coordination and that the unpaired electrons occupy thedx2–y2orbital. Cyclic voltammetric studies show two irreversible oxidation and reduction peaks.

Elucidating the structure of a high-spin σ-phenyliron(iii) species in a live FeCl3–PhZnCl reaction system

2018 ◽  
Vol 54 (12) ◽  
pp. 1481-1484 ◽  
Author(s):  
Zhiliang Huang ◽  
Dongchao Zhang ◽  
Jyh-Fu Lee ◽  
Aiwen Lei
Keyword(s):  
Density Functional ◽  
Reaction System ◽  
Paramagnetic Resonance ◽  
Functional Theory ◽  
System P ◽  
First Time ◽  
X Ray Absorption ◽  
Electron Paramagnetic

Characterization of σ-aryliron(iii) species in a live reaction system: an unknown sextet Ph(THF)FeCl2 species was well-characterized in a live FeCl3–PhZnCl reaction system for the first time by Raman, in situ IR, electron paramagnetic resonance (EPR), X-ray absorption spectroscopic (XAS) and density functional theory (DFT) calculations.

The Interplay of manganese and nitrate in hydroxyapatite nanoparticles as revealed by pulsed EPR and DFT

2015 ◽  
Vol 17 (31) ◽  
pp. 20331-20337 ◽  
Author(s):  
Marat Gafurov ◽  
Timur Biktagirov ◽  
Georgy Mamin ◽  
Elena Klimashina ◽  
Valery Putlayev ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Hydroxyapatite Nanoparticles ◽  
Paramagnetic Resonance ◽  
Functional Theory ◽  
Pulsed Epr ◽  
Pulsed Electron Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Oppositely Charged

The interplay of oppositely charged substitutions in the structure of hydroxyapatite nanopowders is investigated by pulsed electron paramagnetic resonance and ab initio density functional theory calculations.

Radical anions of quinoxalines (an in situ electron paramagnetic resonance spectroelectrochemical and theoretical study)

2014 ◽  
Vol 19 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Karol Lušpai ◽  
Andrej Staško ◽  
Vladimír Lukeš ◽  
Dana Dvoranová ◽  
Zuzana Barbieriková ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Theoretical Study ◽  
Radical Anions ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

scholarly journals DFT Protocol for EPR Prediction of Paramagnetic Cu(II) Complexes and Application to Protein Binding Sites

2018 ◽  
Vol 4 (4) ◽  
pp. 55 ◽  
Author(s):  
Giuseppe Sciortino ◽  
Giuseppe Lubinu ◽  
Jean-Didier Maréchal ◽  
Eugenio Garribba
Keyword(s):  
Binding Sites ◽  
Density Functional ◽  
Computational Procedure ◽  
Paramagnetic Resonance ◽  
Functional Theory ◽  
Protein Binding Sites ◽  
The Mean ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

With the aim to provide a general protocol to interpret electron paramagnetic resonance (EPR) spectra of paramagnetic copper(II) coordination compounds, density functional theory (DFT) calculations of spin Hamiltonian parameters g and A for fourteen Cu(II) complexes with different charges, donor sets, and geometry were carried out using ORCA software. The performance of eleven functionals was tested, and on the basis of the mean absolute percent deviation (MAPD) and standard deviation (SD), the ranking of the functionals for Az is: B3LYP > B3PW91 ~ B3P86 > PBE0 > CAM-B3LYP > TPSSh > BH and HLYP > B2PLYP > MPW1PW91 > ω-B97x-D >> M06; and for gz is: PBE0 > BH and HLYP > B2PLYP > ω-B97x-D > B3PW91~B3LYP~B3P86 > CAM-B3LYP > TPSSh~MPW1PW91 >> M06. With B3LYP the MAPD with respect to A z exp t l is 8.6% with a SD of 4.2%, while with PBE0 the MAPD with respect to g z exp t l is 2.9% with a SD of 1.1%. The results of the validation confirm the fundamental role of the second order spin-orbit contribution to Az. The computational procedure was applied to predict the values of gz and Az of the adducts formed by Cu(II) with albumin and two fragments of prion protein, 106–126 and 180–193.

scholarly journals Electron Inventory of the Iron-Sulfur Scaffold Complex HypCD Essential in [NiFe]-Hydrogenase Cofactor Assembly

2021 ◽  
Author(s):  
Sven T. Stripp ◽  
Jonathan Oltmanns ◽  
Christina S. Müller ◽  
David Ehrenberg ◽  
Ramona Schlesinger ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Redox Activity ◽  
Construction Site ◽  
Iron Ion ◽  
Paramagnetic Resonance ◽  
Iron Sulfur ◽  
Reducing Conditions ◽  
Reversible Redox ◽  
Electron Paramagnetic ◽  
Redox Conversion

The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN– and CO ligands are transferred and attached to the iron ion. We developed an efficient protocol for the production and isolation of the functional HypCD complex that facilitated detailed spectroscopic investigations. The results obtained by UV/Vis-, electron paramagnetic Resonance (EPR)-, Resonance Raman-, Fourier-transform infrared (FTIR), and Mössbauer spectroscopy provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions. We demonstrate the redox activity of the HypCD complex reporting the interconversion of the [4Fe-4S]2+/+ couple. Additionally, we observed a reversible redox conversion between the [4Fe-4S]2+ and a [3Fe-4S]+ cluster. MicroScale thermophoresis indicated preferable binding between the HypCD complex and its interaction partner HypEF under reducing conditions. Together, these results suggest a redox cascade involving the [4Fe-4S] cluster and a conserved disulfide bond of HypD that may facilitate the synthesis of the [Fe](CN)2CO cofactor precursor on the HypCD scaffold complex.

Sign in / Sign up

Export Citation Format

Share Document