Homo pair formations of thiobarbituric acid: DFT calculations and QTAIM analysis

2021 ◽  
pp. 1-11
Author(s):  
Leila Fatahiyan ◽  
Afshin Taghva Manesh ◽  
Nasrin Masan Abadi
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Quantum Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Thiobarbituric Acid ◽  
Pharmaceutical Compounds ◽  
Functional Theory ◽  
Qtaim Analysis ◽  
Different Types

Homo pair formations of thiobarbituric acid (TBA) were investigated in this work by performing density functional theory (DFT) calculations and the quantum theory of atoms in molecule (QTAIM) analysis. Different types of interactions including N–H . . . O, N–H . . . S, C–H . . . O, and C–H . . . S were involved in formations of five models of homo pair of TBA. In this regard, the results of energy strength and QTAIM features indicated that the model with two N–H . . . O interacting bond (D1) was placed at the highest stability and the model with one N–H . . . O and one C–H . . . S interacting bonds (D5) was placed at the lowest stability. Existence of hydrogen bond (HB) interactions in the models were confirmed based on the obtained results. As a consequence, self-interaction of TBA, as an initiator of pharmaceutical compounds production, was investigated in this work in addition to recognition of existence of different types of interactions.

Structural polymorphism of pyrazinium hydrogen sulfate: extending chemistry of the pyrazinium salts with small anions

2010 ◽  
Vol 66 (4) ◽  
pp. 451-457 ◽  
Author(s):  
Armand Budzianowski ◽  
Mariana Derzsi ◽  
Piotr J. Leszczyński ◽  
Michał K. Cyrański ◽  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Dipole Moment ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Density Functional ◽  
Hydrogen Sulfate ◽  
Structural Polymorphism ◽  
Functional Theory ◽  
First Time

Two polymorphs (α, β) of pyrazinium hydrogen sulfate (pyzH+HSO_4^-, abbreviated as PHS) with distinctly different hydrogen-bond types and topologies but close electronic energies have been synthesized and characterized for the first time. The α-polymorph (P212121) forms distinct blocks in which the pyzH+ and HSO_4^- ions are interconnected through a network of NH...O and OH...O hydrogen bonds. The β-form (P\bar 1) consists of infinite chains of alternating pyzH+ and HSO_4^- ions connected by NH...O and OH...N hydrogen bonds. Density functional theory (DFT) calculations indicate the possible existence of a hypothetical polar P1 form of the β-polymorph with an unusually high dipole moment.

Development of transition-metal-catalyzed cycloaddition reactions leading to polycarbocyclic systems

2011 ◽  
Vol 83 (3) ◽  
pp. 495-506 ◽  
Author(s):  
Moisés Gulías ◽  
Fernando López ◽  
José L. Mascareñas
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Dft Calculations ◽  
Density Functional ◽  
Conjugated Dienes ◽  
Ni Catalysts ◽  
Functional Theory ◽  
Different Types ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

We present a compilation of methodologies developed in our laboratories to assemble polycyclic structures containing small- and medium-sized cycles, relying on the use of transition-metal-catalyzed (TMC) cycloadditions. First, we discuss the use of alkylidenecyclopropanes (ACPs) as 3C-atom partners, in particular in their Pd-catalyzed (3 + 2) cycloadditions with alkynes, alkenes, and allenes, reactions that lead to cyclopentane-containing polycyclic products in excellent yields. Then, we present the expansion of this chemistry to a (4 + 3) annulation with conjugated dienes, and to inter- and intramolecular (3 + 2 + 2) cycloadditions using external alkenes as additional 2C-π-systems. These reactions allow the preparation of different types of polycyclic structures containing cycloheptene rings, the topology of the products depending on the use of Pd or Ni catalysts. Finally, we include our more recent discoveries on the development of (4 + 3) and (4 + 2) intramolecular cyclo-additions of allenes and dienes, promoted by Pt and Au catalysts, and discuss mechanistic insights supported by experimental and density functional theory (DFT) calculations. An enantioselective version of the (4 + 2) cycloaddition with phosphoramidite Au(I) catalysts is also presented.

scholarly journals Theoretical investigation of interactions between palladium and fullerene in polymer

RSC Advances ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 2202-2210 ◽  
Author(s):  
Jakub Goclon ◽  
Krzysztof Winkler ◽  
Johannes T. Margraf
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Different Types ◽  
Fullerene Polymers

Applying density functional theory (DFT) calculations, we predict the structural and electronic properties of different types of palladium–fullerene polymers.

Mechanochemical reactions of cocrystals: comparing theory with experiment in the making and breaking of halogen bonds in the solid state

2020 ◽  
Vol 56 (59) ◽  
pp. 8293-8296 ◽  
Author(s):  
Mihails Arhangelskis ◽  
Filip Topić ◽  
Poppy Hindle ◽  
Ricky Tran ◽  
Andrew J. Morris ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Dft Calculations ◽  
Density Functional ◽  
Halogen Bonds ◽  
Functional Theory ◽  
Different Types ◽  
Mechanochemical Reactions

The interconversions of halogen-bonded cocrystals exhibiting three different stoichiometries were predicted by different types of dispersion-corrected density functional theory (DFT) calculations and predictions experimentally validated by mechanochemistry.

Formations of bimolecular barbituric acid complexes through hydrogen bonding interactions: DFT analyses of structural and electronic features

2021 ◽  
pp. 1-11
Author(s):  
Narjes Hajali ◽  
Afshin Taghva Manesh ◽  
Ahmad Seif
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bonding ◽  
Dft Calculations ◽  
Density Functional ◽  
Barbituric Acid ◽  
Pharmaceutical Compounds ◽  
Functional Theory ◽  
Hydrogen Bonding Interactions ◽  
Starting Compound ◽  
Dimer Models

Formations of bimolecular barbituric acid (BA) complexes through hydrogen-bonding (HB) interactions were investigated in this work. BA has been known as a starting compound of pharmaceutical compounds developments, in which the molecular and atomic features of parent BA in homo-paring with another BA molecule were investigated here. The models were optimized to reach the stabilized structures and their properties were evaluated at the molecular and atomic scales. Density functional theory (DFT) calculations were performed to provide required information for achieving the goal of this work. Six dimer models were obtained finally according to examining all possible starting dimers configurations for involving in optimization calculations. N-H . . . O and C-H . . . O interactions were also involved in dimers formations besides participation of the X-center of parent BA in interaction. Molecular and atomic scales features were evaluated for characterizing the dimers formations. As a consequence, several configurations of BA dimers were obtained showing the importance of performing such structural analyses for developing further compounds from BA.

γ-Valerolactone-Introduced Controlled-Isomerization of Glucose for Lactic Acid Production over Sn-Beta Catalyst

2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lactic Acid ◽  
Dft Calculations ◽  
Acid Production ◽  
Density Functional ◽  
Lactic Acid Production ◽  
Hydrothermal Conversion ◽  
Functional Theory ◽  
Environment Friendly

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...

Mechanistic understanding of the Cu(i)-catalyzed domino reaction constructing 1-aryl-1,2,3-triazole from electron-rich aryl bromide, alkyne, and sodium azide: a DFT study

2021 ◽  
Author(s):  
Hanlin Gan ◽  
Liang Peng ◽  
Feng Long Gu
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Sodium Azide ◽  
Density Functional ◽  
Dft Study ◽  
Domino Reaction ◽  
Aryl Bromide ◽  
Functional Theory ◽  
Mechanistic Understanding

The mechanism of the Cu(i)-catalyzed domino reaction furnishing 1-aryl-1,2,3-triazole assisted by CuI and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is explored with density functional theory (DFT) calculations.

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.

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

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