scholarly journals Quantum-Chemical Consideration of Al2M2 Tetranuclear Metal Clusters (M–3d-Element): Molecular/Electronic Structures and Thermodynamics

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6836
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Electronic Structures ◽  
Quantum Chemical ◽  
Metal Clusters ◽  
Molecular Structures ◽  
Chemical Calculation ◽  
Geometric Form ◽  
Structural Isomers ◽  
Torsion Angles ◽  
Homo And Lumo ◽  
The Given

Quantum-chemical calculation of most important parameters of molecular and electronic structures of tetra-nuclear (pd) metal clusters having Al2M2 composition, where M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, or Zn (bond lengths, bond and torsion angles), and HOMO and LUMO of these compounds by means of DFT OPBE/QZVP method, have been carried out. It has been found that, for each of these metal clusters, an existence of rather large amount of structural isomers different substantially in their total energy, occurs. It has been noticed that molecular structures of metal clusters of the given type differ significantly between them in terms of geometric parameters, as well as in geometric form, wherein the most stable modifications of metal clusters considered are similar between themselves in geometric form. In addition, the standard thermodynamic parameters of formation of metal clusters considered here, and namely standard enthalpy ΔfH0(298 K), entropy Sf0(298 K), and Gibbs’ energy ΔfG0(298 K) of formation for these metal clusters, were calculated.

scholarly journals Quantum-Chemical Design of Molecular Structures of Tetra-, Penta- and Hexanuclear Metal Clusters Containing Aluminum and 3d-Element Atoms

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1852
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Ground State ◽  
Quantum Chemical ◽  
Metal Clusters ◽  
Complex Dynamics ◽  
Thermodynamic Characteristics ◽  
Molecular Structures ◽  
Spin Multiplicity ◽  
Structural Isomers ◽  
The Individual ◽  
The Given

Various data on the structural and thermodynamic characteristics of polynuclear metal clusters containing atoms of aluminum and various d-elements with the general formula AlnMm where (n + m) is 4, 5, or 6, and which can be precursors for the formation of nanoparticles of elemental metals or intermetallic compounds, have been systematized and discussed. It has been noted that each of these metal clusters in principle is able to exist in very diverse structural isomers, differing significantly among themselves in terms of the total energy and spin multiplicity of the ground state, the number of which is determined by both the specific values of n and m, and the nature of d-elements in their compositions. The presence of very complex dynamics with respect to the changes of the individual thermodynamic characteristics of the metal clusters under consideration as well as the thermodynamic parameters of the reactions of their formation, depending on the nature of the d-element, were also ascertained. In the main, the given review is devoted to the authors’ works published over the last 10 years. Bibliography – 96 references.

scholarly journals Models of Molecular Structures of Hexa-Nuclear AlnFem Metal Clusters (n + m = 6): DFT Quantum-Chemical Design

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 597
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Metal Clusters ◽  
Dft Method ◽  
Molecular Structures ◽  
Dihedral Angles ◽  
Geometric Form ◽  
Structural Isomers ◽  
Functional Theory ◽  
The Density Functional Theory

By using the density functional theory (DFT) method at the OPBE/QZVP level, key parameters of molecular structures of six-atomic (heterobi)nuclear metal clusters with an AlnFem composition (n + m = 6) (bond lengths, bond angles, and torsion (dihedral) angles) were calculated. It was found that each of these clusters exists in a large number of structural isomers that differ substantially in terms of their total energy. Furthermore, the molecular structures of these structural isomers significantly differ regarding the geometric parameters and geometric form. In addition, the most stable structural isomers of these metal clusters also differ rather considerably in terms of the geometric form.

scholarly journals Preamble from the Guest Editor of Special Issue “DFT Quantum-Chemical Calculation of Metal Clusters”

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 442
Author(s):  
Oleg V. Mikhailov
Keyword(s):  
Guest Editor ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Chemical Structure ◽  
Metal Clusters ◽  
Chemical Calculation ◽  
Special Issue

As known, the concept of “cluster” is collective and includes substances that are quite diverse in composition and chemical structure [...]

(H,H)-Isomerism of cis- and trans-di[benzo]porphyrazines: Quantum chemical modeling within the framework of the DFT method

2021 ◽  
pp. A-H
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Dft Method ◽  
Relative Energy ◽  
Molecular Structures ◽  
Mutual Orientation ◽  
Chemical Calculation ◽  
Hydrogen Atoms ◽  
Trans Orientation ◽  
Cis And Trans

Quantum-chemical calculation of the molecular structures of potential isomeric (NNNN)- donoratomic macrocyclic tetradentate ligands, cis- and trans-di[benzo]porphyrazines, was carried out using the density functional theory (DFT) B3PW91/TZVP. It is noted that the first of these compounds can exist in four forms [so-called ([Formula: see text]-isomers], differing from each other by the mutual orientation of hydrogen atoms bonded to the nitrogen atoms, while the second compounds take the form of two similar isomers. The values of the most important bond lengths, bond and non-bond angles in each of these ([Formula: see text] -isomeric compounds, as well as the values of their relative energy, standard enthalpy, entropy, and Gibbs energy of formation are presented. It was found that the most stable among both cis- and trans-di[benzo]porphyrazines is the ([Formula: see text]-isomer with the trans-orientation of hydrogen atoms bonded to nitrogen atoms, while the ([Formula: see text] -isomers with cis-oriented hydrogen atoms for both of these compounds had significantly higher relative energies.

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