AB INITIO AND DFT STUDY OF NON-COVALENT INTERACTIONS BETWEEN RARE GAS ATOMS AND AROMATIC RINGS

2013 ◽  
Vol 12 (03) ◽  
pp. 1350012 ◽  
Author(s):  
CHENG CHENG ◽  
MIN ZHANG ◽  
LI SHENG
Keyword(s):  
Ab Initio ◽  
Weak Interaction ◽  
Density Functional ◽  
Nbo Analysis ◽  
Basis Sets ◽  
Rare Gas ◽  
Aromatic Rings ◽  
Functional Theory ◽  
Rare Gas Atoms ◽  
Non Covalent Interactions

In this paper, the weak interaction between aromatic rings (ARs) and rare gas (Rg) atoms has been studied using ab initio calculation and density functional theory (DFT). The augmented Dunning basis sets were used, and the convergence test was performed up to aug-cc-pV5Z. Among the computationally feasible methods, ωB97XD performed the best for these non-covalent systems. NBO analysis was performed to investigate the nature of the Rg/AR interactions. In this type of weak interaction, the induced and instantaneous dipole and charge transfer character both contribute to the interaction energies and equilibrium distances.

scholarly journals 1,3,5-Triaza-7-Phosphaadamantane (PTA) as a 31P NMR Probe for Organometallic Transition Metal Complexes in Solution

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1390 ◽  
Author(s):  
Ilya G. Shenderovich
Keyword(s):  
Chemical Shift ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional ◽  
Molecular Structures ◽  
Basis Sets ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Due to the rigid structure of 1,3,5-triaza-7-phosphaadamantane (PTA), its 31P chemical shift solely depends on non-covalent interactions in which the molecule is involved. The maximum range of change caused by the most common of these, hydrogen bonding, is only 6 ppm, because the active site is one of the PTA nitrogen atoms. In contrast, when the PTA phosphorus atom is coordinated to a metal, the range of change exceeds 100 ppm. This feature can be used to support or reject specific structural models of organometallic transition metal complexes in solution by comparing the experimental and Density Functional Theory (DFT) calculated values of this 31P chemical shift. This approach has been tested on a variety of the metals of groups 8–12 and molecular structures. General recommendations for appropriate basis sets are reported.

scholarly journals Tipping the balance: theoretical interrogation of divergent extended heterolytic fragmentations

2020 ◽  
Vol 11 (8) ◽  
pp. 2231-2242 ◽  
Author(s):  
Croix J. Laconsay ◽  
Ka Yi Tsui ◽  
Dean J. Tantillo
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Electric Field ◽  
Ab Initio ◽  
External Electric Field ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Nbo Analysis ◽  
Functional Theory

We interrogate a type of heterolytic fragmentation called a ‘divergent fragmentation’ using density functional theory (DFT), natural bond orbital (NBO) analysis, ab initio molecular dynamics (AIMD), and external electric field (EEF) calculations.

scholarly journals Armchair Boron Nitride nanotubes—heterocyclic molecules interactions: A computational description

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Ernesto Chigo Anota ◽  
Gregorio Hernández Cocoletzi ◽  
Andres Manuel Garay Tapia
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Density Functional ◽  
Boron Nitride Nanotubes ◽  
Functional Theory ◽  
Heterocyclic Molecules ◽  
Non Covalent Interactions ◽  
Covalent Interactions

AbstractAb-initio calculations using density functional theory (DFT) are used to investigate the non-covalent interactions between single wall armchair boron nitride nanotubes (BNNTs) with open ends and several heterocyclic molecules: thiophene (T; C

THE ORIGIN OF THE ROTATIONAL BARRIER IN DIMETHYL ETHER AND DIMETHYL SULFIDE: A THEORETICAL STUDY

2007 ◽  
Vol 06 (03) ◽  
pp. 421-434 ◽  
Author(s):  
JÍMENEZ-FABIAN ◽  
A. F. JALBOUT
Keyword(s):  
Dimethyl Ether ◽  
Density Functional ◽  
Dimethyl Sulfide ◽  
Nbo Analysis ◽  
Rotational Barrier ◽  
Basis Sets ◽  
Functional Theory ◽  
Hartree Fock ◽  
Torsional Potential ◽  
Methyl Rotation

The torsional potential function for methyl rotation in dimethyl ether (DME) and dimethyl sulfide (DMS) has been determined by utilizing ab initio (Hartree–Fock and MP2) and density functional theory (B3LYP, B3P86, and B3PW91) methods along with several basis sets. Natural bond orbital (NBO) analysis was also applied to investigate the origin of the rotational barrier.

Insight on the Factors Controlling the Equilibrium of Allylic Azides

2019 ◽  
Author(s):  
Margarita Vallejos ◽  
Guillermo Labadie
Keyword(s):  
Weak Interaction ◽  
Density Functional ◽  
Equilibrium Mixture ◽  
Hydroxyl Group ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
Allylic Azides ◽  
Covalent Interactions ◽  
Insight Into ◽  
Good Linear Correlation

<p>Several allylic azides with different double bond substitution were studied to understand the factors governing their equilibrium using density functional theory along with quantum theory of atoms in molecules, Non-covalent Interactions and Natural Bond Orbitals approaches. The results showed the hydroxyl group or heteroatoms in allylic azides interact with the molecule through an electrostatic weak interaction in each pair of regioisomers. The equilibrium shifts of substituted allylic azides, compared to non-substituted allylic azides, are not attributed to the presence of specific interactions, such as hydrogen bond. The observed equilibrium shifts stem mainly from the strengthening and weakening of negative hyperconjugative interactions, which is affected by the weak interaction involving the proximal substituent in each regioisomer. A good linear correlation was obtained between the hyperconjugative energies of pC=C→s*<i>Z</i><sub>b</sub> interactions and the calculated percentages of secondary azide and tertiary azides in the equilibrium mixture. Also, the effect of aromatic ring substituent was analysed using such approaches. This study not only provides insight into the factor controlling the stabilities of the substituted allylic azides, but also settle the basis to predict the regioisomer predominance in the equilibrium mixture.</p>

scholarly journals Ability of B12N12 fullerènes like nano-cage for sensing and improving the antioxidant activity of juglone and its derivative: DFT investigation

2021 ◽  
Author(s):  
Vincent de Paul Zoua ◽  
Aymard Fouegue ◽  
Désiré Mama ◽  
Julius Ghogomu ◽  
Rahman Abdoul Ntieche
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Nbo Analysis ◽  
Hydrogen Atom Transfer ◽  
Carbonyl Groups ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
A Charge ◽  
Covalent Interactions ◽  
Theoretical Results

Density functional theory (DFT) calculations were adopted in this work to investigate the ability of the B12N12 fullerene like nano-cage for sensing juglone (Jug) and one of its derivative (Jug-OH) using DFT based methods in gas phase, pentyl ethanoate (PE) and water. Results showed that B12N12 is able to adsorbed Jug preferentially by binding to one of the O-atom of its carbonyl groups. Based on NBO analysis, a charge transfer from the oxygen atoms of Jug and Jug-OH to the anti-bonding orbital of B was revealed. QTAIM analysis showed that the B12N12-Jug and B12N12-Jug-OH complexes are stabilized by a partially covalent B-O bond in addition to attractive non covalent interactions. The ability of Jug, Jug-OH as well as their complexes A and A-OH to scavenge radicals has been investigated via the usual hydrogen atom transfer (HAT) mechanism in the three media of study previously stated. Theoretical results revealed that in PE and water, the complexes are better antioxidant than Jug and Jug-OH. These results provide fundamental knowledge for the development of new antioxidant delivery careers.

Stereoelectronic interaction effects on the conformational properties of 5-methyl-5-aza-1,3-dithiacyclohexane and its analogous containing N, P, O, and Se atoms — A hybrid density functional theory (DFT), ab initio study, and natural bond orbital (NBO) analysis

2010 ◽  
Vol 88 (7) ◽  
pp. 579-587 ◽  
Author(s):  
Davood Nori-Shargh ◽  
Neda Hassanzadeh ◽  
Meisam Kosari ◽  
Parvin Rabieikarahroudi ◽  
Hooriye Yahyaei ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Natural Bond Orbital ◽  
Nbo Analysis ◽  
Hybrid Density Functional Theory ◽  
Functional Theory ◽  
Dipole Interactions ◽  
Conformational Properties ◽  
Hybrid Density Functional

Natural bond orbital (NBO) analysis, hybrid density functional theory (hybrid DFT: B3LYP/6-311+G**//B3LYP/6-311+G**), and ab initio molecular orbital (MO: MP2/6-311+G**//B3LYP/6-311+G**) based methods were used to study the electronic delocalization energy (DE), dipole–dipole interactions, and steric repulsions on the conformational properties of 5-methyl-5-aza-1,3-dioxacyclohexane (1) (-phospha- (2), -arsena- (3)), 5-methyl-5-aza-1,3-dithiacyclohexane (4) (-phospha- (5), -arsena- (6)), and 5-methyl-5-aza-1,3-diselenacyclohexane (7) (-phospha- (8), -arsena- (9)). The MP2/6-311+G**//B3LYP/6-311+G** and B3LYP/6-311+G**//B3LYP/6-311+G** results revealed that the axial stereoisomers of compounds 1–9 are more stable than their equatorial stereoisomers. In this regard, the obtained results showed an egregious axial preference for compounds 1, 4, and 7. Importantly, the results showed that the energy differences between the axial and equatorial stereoisomers decrease from compounds 1 → 3, 4 → 6, and also, 7 → 9. The NBO analysis of donor–acceptor interactions revealed that the calculated DE for compounds 1–3 are –21.50, –7.84, and –4.38 kcal mol–1, respectively. The decrease of the calculated DE values from compound 1 to compound 3 could reasonably explain the decrease of the energy differences between the axial and equatorial stereoisomers from compound 1 to compound 3. The correlation between the DE, dipole–dipole interactions, structural parameters, and conformational behaviors of compounds 1–9 has been investigated.

scholarly journals Coordination Behavior of Ni2+, Cu2+, and Zn2+ in Tetrahedral 1-Methylimidazole Complexes: A DFT/CSD Study

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Samuel Tetteh
Keyword(s):  
Density Functional ◽  
Population Analysis ◽  
Substantial Reduction ◽  
Nbo Analysis ◽  
Basis Sets ◽  
Dft Methods ◽  
Functional Theory ◽  
Formal Charge ◽  
Coordination Behavior ◽  
The Stability

The interaction between nickel (Ni2+), copper (Cu2+), and zinc (Zn2+) ions and 1-methylimidazole has been studied by exploring the geometries of eleven crystal structures in the Cambridge Structural Database (CSD). The coordination behavior of the respective ions was further investigated by means of density functional theory (DFT) methods. The gas-phase complexes were fully optimized using B3LYP/GENECP functionals with 6-31G∗ and LANL2DZ basis sets. The Ni2+ and Cu2+ complexes show distorted tetrahedral geometries around the central ions, with Zn2+ being a perfect tetrahedron. Natural bond orbital (NBO) analysis and natural population analysis (NPA) show substantial reduction in the formal charge on the respective ions. The interaction between metal d-orbitals (donor) and ligand orbitals (acceptor) was also explored using second-order perturbation of the Fock matrix. These interactions followed the order Ni2+ > Cu2+ > Zn2+ with Zn2+ having the least interaction with the ligand orbitals. Examination of the frontier orbitals shows the stability of the complexes in the order Ni2+ > Cu2+ < Zn2+ which is consistent with the Irving–Williams series.

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