scholarly journals Quantum Chemical Study of Spin Transitions in the Bimetallic Fe/Co Complexes with the Bis(catecholate) Bridging Ligand

2021 ◽  
Vol 47 (9) ◽  
pp. 601-609
Author(s):  
M. G. Chegerev ◽  
A. G. Starikov ◽  
A. A. Starikova
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Density Functional Theory Method ◽  
Chemical Study ◽  
Functional Theory ◽  
Energy Characteristics ◽  
Bridging Ligand ◽  
The Density Functional Theory ◽  
Spin Transitions

Abstract The computational modeling of the spatial and electronic structures, energy characteristics, and magnetic properties of the bimetallic iron and cobalt complexes with 9,10-dimethyl-9,10-ethano-9,10-dihydro-2,3,6,7-tetrahydroxyanthracene and terminal tris(2-pyridylmethyl)amine bases is performed using the density functional theory method (DFT UTPSSh/6-311++G(d,p)). The chosen tetradentate redox ligand is shown to be a promising precursor for the production of magnetically active compounds. The calculations make it possible to establish a relationship between the relative energies of the electronic isomers of the complexes and the structures of the ancillary N-donor moieties. The coordination compounds prone to the manifestation of spin transitions accompanied by a change in the magnetic properties are revealed.

scholarly journals Quantum Chemical Study of Mixed-Ligand Monometallic Ruthenium(II) Complex of Composition [(bpy)2Ru(H3Imbzim)](ClO4)2·2H2O

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Mohsin Yousuf Lone ◽  
Prakash Chandra Jha
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Mixed Ligand ◽  
Excitation Energies ◽  
Functional Theory ◽  
Effect Of Solvent ◽  
The Density Functional Theory ◽  
Metal Ligand

On the basis of density functional theoretical approach, we have assessed the ground state geometries and absorption spectra of recently synthesized monometallic ruthenium (II) complex of composition [(bpy)2Ru(H3Imbzim)](ClO4)2·2H2O where bpy = 2,2′-bypyridine and H3Imbzim = 4,5-bis(benzimidazol-2-yl)imidazole. The all different kinds of charge transfers such as ligand-ligand, and metal-ligand have been quantified, compared, and contrasted with the experimental results. In addition, the effect of solvent on excitation energies has been evaluated. In spite of some digital discrepancies in calculated and observed geometries, as well as in absorption spectra, the density functional theory (DFT) seems to explain the main features of this complex.

Quantum-chemical study of nitrogen and magnesium co-doping in α-Cr2O3

2016 ◽  
Vol 30 (14) ◽  
pp. 1650219
Author(s):  
Soraya Jácome ◽  
Arvids Stashans
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Text Type ◽  
Co Doping ◽  
The Density Functional Theory

Study of corundum-type chromium oxide ([Formula: see text]-Cr2O3) crystal doped with the nitrogen and magnesium impurities has been carried out through the use of first-principles calculations based on the density functional theory (DFT) and generalized gradient approximation (GGA). Three cases corresponding different impurity–impurity distances have been considered. Structural, electronic and magnetic properties have been studied for all co-doping cases. The [Formula: see text]-type electrical conductivity was found when distance between the Mg and N atoms is equal to 4.10 Å. The results obtained are consistent with the available experimental data.

First-Principle Study on Magnetic Properties of TM-Doped 6H-SiC

2013 ◽  
Vol 709 ◽  
pp. 197-200 ◽  
Author(s):  
Pei Ting Ma ◽  
Tian Min Lei ◽  
Yu Ming Zhang ◽  
Jia Jia Liu ◽  
Zhi Yong Zhang
Keyword(s):  
Magnetic Properties ◽  
Density Of States ◽  
Density Functional ◽  
Density Functional Theory Method ◽  
Ferromagnetic State ◽  
Partial Density ◽  
Functional Theory ◽  
Half Metallic ◽  
The Density Functional Theory ◽  
Mn Doped

Magnetic properties of 6H-SiC doped with transition metal (TM) atoms are calculated using the density functional theory method (DFT). It is shown that TM doped in a 6H-SiC host may have both magnetic and nonmagnetic states. From the figures of their density of states (DOS) and partial density of states (PDOS) and to compare the energy differences between ferromagnetic and nonmagnetic states, we demonstrate that Cr and Mn-doped 6H-SiC emerge a half-metallic ferromagnetic state, Co and Ni-doped 6H-SiC create very little magnetic features, while Fe-doped 6H-SiC is in the nonmagnetic state. We also calculate the energy differences between ferromagnetic and antiferromagnetic of Cr, Mn and Fe-doped 6H-SiC in the doping concentration (8.34%). It is found that the energy of the antiferromagnetic state is lower than that of the ferromagnetic state.

scholarly journals A GRADIENT-CORRECTED HYBRID HF–DFT STUDY OF STRUCTURE AND VIBRATIONAL SPECTROSCOPIC PROPERTIES OF THE DICHLORODIOXOCHROMIUM(VI) COMPLEX WITH 1,10-PHENANTHROLINE

2017 ◽  
Vol 27 (1-2) ◽  
Author(s):  
Ljupčo Pejov ◽  
Mira Trpkovska ◽  
Bojan Šoptrajanov
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Quantum Chemical Study ◽  
Dft Method ◽  
Chemical Study ◽  
Spectroscopic Properties ◽  
Stationary Points ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Gradient Optimization

A b s t r a c t: In order to get a more exact basis for the band assignments in the case of dichlorodioxochromium(VI) complex with 1,10-phenanthroline (especially regarding the order of appearance of the antisymmetric and symmetric CrO2 stretching bands) a quantum chemical study of this system was carried out. Two levels of theory were employed – the HF/6-31++G(d,p) and the density-functional-theory-based (DFT) method B3–LYP/6- 31++G(d,p). Full geometry optimizations of the title complex were carried out, employing Schlegel's gradient optimization algorithm. Harmonic vibrational analyses of the stationary points located on both potential energy hypersurfaces were subsequently carried out in order to test their character and to compute the harmonic vibrational frequencies of the complex. Predictions of the ab initio and DFT quantum chemical approaches regarding the order of appearance of the antisymmetric and symmetric CrO2 stretching bands in the case of the studied complex were compared to the cases of analogous 2,2'-bipyridine and 2,2'-biquinoline complexes containing the CrO2 group, which were previously studied by us [1–6].

scholarly journals Dinuclear cobalt and iron complexes with azomethine derivative of 1,10-phenanthroline: quantum chemical study

2019 ◽  
Vol 487 (1) ◽  
pp. 36-40
Author(s):  
А. А. Starikova ◽  
M. G. Chegerev ◽  
A. G. Starikov ◽  
V. I. Minkin
Keyword(s):  
Density Functional ◽  
Quantum Chemical Study ◽  
Density Functional Theory Method ◽  
Chemical Study ◽  
Magnetic Characteristics ◽  
Functional Theory ◽  
Valence Tautomerism ◽  
Ancillary Ligands ◽  
Wide Range ◽  
Active Fragments

Geometry, energy and magnetic characteristics of binuclear compounds of 5,6-bis(salicylideneimino)-1,10-phenanthroline with cobalt and iron have been computationally studied by means of density functional theory method (DFT UTPSSh/6-311++G(d, p)). Complexes comprising two magnetically active fragments capable of manifesting spin-crossover and valence tautomerism have been constructed via completion of the coordination sphere of the metal ions with ancillary ligands. These effects provide for variation of spin states in a wide range, which endows the studied compounds properties of molecular switches and spin qubits.

Study of the Stability and Chemical Reactivity of a Series of Tetrazole Pyrimidine Hybrids by the Density Functional Theory Method (DFT)

2021 ◽  
Vol 37 (4) ◽  
pp. 805-812
Author(s):  
Ahissandonatien Ehouman ◽  
Adjoumanirodrigue Kouakou ◽  
Fatogoma Diarrassouba ◽  
Hakim Abdel Aziz Ouattara ◽  
Paulin Marius Niamien
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Molecular Descriptors ◽  
Chemical Reactivity ◽  
Density Functional Theory Method ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
The Stability ◽  
Global Reactivity Descriptors

Our theoretical study of stability and reactivity was carried out on six (06) molecules of a series of pyrimidine tetrazole hybrids (PTH) substituted with H, F, Cl, Br, OCH3 and CH3 atoms and groups of atoms using the density function theory (DFT). Analysis of the thermodynamic formation quantities confirmed the formation and existence of the series of molecules studied. Quantum chemical calculations at the B3LYP / 6-311G (d, p) level of theory determined molecular descriptors. Global reactivity descriptors were also determined and analyzed. Thus, the results showed that the compound PTH_1 is the most stable, and PTH_5 is the most reactive and nucleophilic. Similarly, the compound PTH_4 is the most electrophilic. The analysis of the local descriptors and the boundary molecular orbitals allowed us to identify the preferred atoms for electrophilic and nucleophilic attacks.

scholarly journals Practical and Theoretical Study on the Inhibitory Influences of New Azomethine Derivatives Containing an 8-Hydroxyquinoline Moiety for the Corrosion of Carbon Steel in 1 M HCl

2018 ◽  
Vol 34 (6) ◽  
pp. 3016-3029 ◽  
Author(s):  
A. El-Yaktini ◽  
A. Lachiri ◽  
M. El-Faydy ◽  
F. Benhiba ◽  
H. Zarrok ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Density Functional Theory Method ◽  
Steel Corrosion ◽  
Experimental Results ◽  
Chemical Parameters ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Inhibition Ability

The inhibition ability of a new Azomethine derivatives containing the 8-hydroxyquinoline (BDHQ and MDHQ) towards carbon steel corrosion in HCl solution was studied at various concentrations and temperatures using weight loss, polarization curves and electrochemical impedance spectroscopy (EIS) methods. The experimental results reveal that BDHQ and MDHQ are efficient mixed type corrosion inhibitors, and their inhibition efficiencies increase with increasing concentration. The adsorption of these inhibitors on mild steel surface obeys Langmuir isotherm. Quantum chemical parameters are calculated using the Density Functional Theory method (DFT) and Monte Carlo simulations. Correlation between theoretical and experimental results is discussed.

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