Molecular interactions of indomethacin and amino acids: Computational approach

2021 ◽  
pp. 1-11
Author(s):  
Ali Parkan ◽  
Mahmoud Mirzaei ◽  
Naser Tavakoli ◽  
Alireza Homayouni
Keyword(s):  
Amino Acids ◽  
Density Functional Theory ◽  
Quantum Theory ◽  
Molecular Interactions ◽  
Density Functional ◽  
Computational Approach ◽  
Strong Interactions ◽  
Interaction Energies ◽  
Functional Theory ◽  
Computational Approaches

Molecular interactions of indomethacin (IND) and amino acids (AA) were investigated in this work by employing the computational approaches. To this aim, the models of IND-AA were stabilized by performing density functional theory (DFT) calculations yielding the most favorable configurations regarding the energy values. Next, the approach of quantum theory of atoms in molecules (QTAIM) was used to recognize the roles of interactions and their significance in the bimolecular models. The results of interaction energies indicate that tryptophan (TRP) and phenylalanine (PHE) could be considered for participating in strong interactions with the IND substance. The results of QTAIM indicated that not only the electronegative atomic centers, but also homo-atomic centers could play significant roles in formations of IND-AA bimolecular models.

scholarly journals Theoretical Investigations of the BaRh2Ge4X6 (X = S, Se, Te) Compounds

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6434
Author(s):  
Pascal Boulet ◽  
Marie-Christine Record
Keyword(s):  
Density Functional Theory ◽  
Quantum Theory ◽  
Electronic Transport ◽  
Figure Of Merit ◽  
Density Functional ◽  
Atoms In Molecules ◽  
Van Der Waals Interactions ◽  
Functional Theory ◽  
Computational Approaches ◽  
Theoretical Investigations

The thermoelectric (TE) properties of the BaM2Ge4X6 compounds, where M = Rh and X = S, Se, Te, were investigated by computational approaches using density-functional theory and semi-classical Boltzmann theory for electronic transport. It was found that these compounds bear good TE properties, in particular BaRh2Ge4Te6, for which the figure of merit was estimated to reach 1.51 at 300 K. As this compound has not yet been proved to be stable, we also investigated BaRh2Ge4S4Te2 by assuming that replacing tellurium by sulphur could stabilize the tellurium-containing structure. It was found that the TE properties are good. The quantum theory of atoms in molecules was used to investigate the nature of the chemical interactions that prevail in these compounds. A wide variety of interactions were evidenced, from van der Waals interactions to ionic and polar-covalent ones, which could explain the good TE performance of these compounds.

On the Nature of Halide-Water Interactions: Insights from Many-Body Representations and Density Functional Theory

2019 ◽  
Author(s):  
Brandon B. Bizzarro ◽  
Colin K. Egan ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Orbital Energy ◽  
Energy Decomposition Analysis ◽  
Interaction Energies ◽  
Many Body ◽  
Functional Theory

<div> <div> <div> <p>Interaction energies of halide-water dimers, X<sup>-</sup>(H<sub>2</sub>O), and trimers, X<sup>-</sup>(H<sub>2</sub>O)<sub>2</sub>, with X = F, Cl, Br, and I, are investigated using various many-body models and exchange-correlation functionals selected across the hierarchy of density functional theory (DFT) approximations. Analysis of the results obtained with the many-body models demonstrates the need to capture important short-range interactions in the regime of large inter-molecular orbital overlap, such as charge transfer and charge penetration. Failure to reproduce these effects can lead to large deviations relative to reference data calculated at the coupled cluster level of theory. Decompositions of interaction energies carried out with the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method demonstrate that permanent and inductive electrostatic energies are accurately reproduced by all classes of XC functionals (from generalized gradient corrected (GGA) to hybrid and range-separated functionals), while significant variance is found for charge transfer energies predicted by different XC functionals. Since GGA and hybrid XC functionals predict the most and least attractive charge transfer energies, respectively, the large variance is likely due to the delocalization error. In this scenario, the hybrid XC functionals are then expected to provide the most accurate charge transfer energies. The sum of Pauli repulsion and dispersion energies are the most varied among the XC functionals, but it is found that a correspondence between the interaction energy and the ALMO EDA total frozen energy may be used to determine accurate estimates for these contributions. </p> </div> </div> </div>

scholarly journals Atoms in Highly Symmetric Environments: H in Rhodium and Cobalt Cages, H in an Octahedral Hole in MgO, and Metal Atoms Ca-Zn in C20 Fullerenes

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1281
Author(s):  
Zikri Altun ◽  
Erdi Ata Bleda ◽  
Carl Trindle
Keyword(s):  
Density Functional Theory ◽  
Quantum Theory ◽  
Coordination Number ◽  
Electronic Structures ◽  
Density Functional ◽  
Functional Theory ◽  
Metal Atoms ◽  
Tetragonal Pyramidal ◽  
Non Covalent Interactions ◽  
Covalent Interactions

An atom trapped in a crystal vacancy, a metal cage, or a fullerene might have many immediate neighbors. Then, the familiar concept of valency or even coordination number seems inadequate to describe the environment of that atom. This difficulty in terminology is illustrated here by four systems: H atoms in tetragonal-pyramidal rhodium cages, H atom in an octahedral cobalt cage, H atom in a MgO octahedral hole, and metal atoms in C20 fullerenes. Density functional theory defines structure and energetics for the systems. Interactions of the atom with its container are characterized by the quantum theory of atoms in molecules (QTAIM) and the theory of non-covalent interactions (NCI). We establish that H atoms in H2Rh13(CO)243− trianion cannot be considered pentavalent, H atom in HCo6(CO)151− anion cannot be considered hexavalent, and H atom in MgO cannot be considered hexavalent. Instead, one should consider the H atom to be set in an environmental field defined by its 5, 6, and 6 neighbors; with interactions described by QTAIM. This point is further illustrated by the electronic structures and QTAIM parameters of M@C20, M=Ca to Zn. The analysis describes the systematic deformation and restoration of the symmetric fullerene in that series.

6-Bromoindigo dye

2012 ◽  
Vol 68 (4) ◽  
pp. o160-o163 ◽  
Author(s):  
David J. Szalda ◽  
Keith Ramig ◽  
Olga Lavinda ◽  
Zvi C. Koren ◽  
Lou Massa
Keyword(s):  
Density Functional Theory ◽  
Quantum Theory ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Stacking Interactions ◽  
Inversion Center ◽  
Asymmetric Unit ◽  
Functional Theory ◽  
Bond Lengths ◽  
Type C

6-Bromoindigo (MBI) [systematic name: 6-bromo-2-(3-oxo-2,3-dihydro-1H-indol-2-ylidene)-2,3-dihydro-1H-indol-3-one], C16H9BrN2O2, crystallizes with one disordered molecule in the asymmetric unit about a pseudo-inversion center, as shown by the Br-atom disorder of 0.682 (3):0.318 (3). The 18 indigo ring atoms occupy two sites which are displaced by 0.34 Å from each other as a result of this packing disorder. This difference in occupancy factors results in each atom in the reported model used to represent the two disordered sites being 0.08 Å from the higher-occupancy site and 0.26 Å from the lower-occupancy site. Thus, as a result of the disorder, the C—Br bond lengths in the disordered components are 0.08 and 0.26 Å shorter than those found in 6,6′-dibromoindigo (DBI) [Süsse & Krampe (1979).Naturwissenschaften,66, 110], although the distances within the indigo ring are similar to those found in DBI. The crystals are also twinned by merohedry. Stacking interactions and hydrogen bonds are similar to those found in the structures of indigo and DBI. In MBI, an interaction of the type C—Br...C replaces the C—Br...Br interactions found in DBI. The interactions in MBI were calculated quantum mechanically using density functional theory and the quantum theory of atoms in molecules.

scholarly journals Predicting Core Level Photoelectron Spectra of Amino Acids Using Density Functional Theory

2020 ◽  
Vol 11 (6) ◽  
pp. 2256-2262
Author(s):  
Jo M. Pi ◽  
Martina Stella ◽  
Nathalie K. Fernando ◽  
Aaron Y. Lam ◽  
Anna Regoutz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Density Functional Theory ◽  
Density Functional ◽  
Core Level ◽  
Photoelectron Spectra ◽  
Functional Theory
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