A DFT-D study on the stability and intramolecular interactions of the salts of 1,2,3- and 1,2,4-triazoles

2014 ◽  
Vol 92 (11) ◽  
pp. 1111-1117
Author(s):  
Xueli Zhang ◽  
Xuedong Gong
Keyword(s):  
Hydrogen Bonds ◽  
Density Functional ◽  
Energy Gap ◽  
Lattice Energy ◽  
Intramolecular Interactions ◽  
Dispersion Energy ◽  
Functional Theory ◽  
Formation Reaction ◽  
The Stability ◽  
Intramolecular Hydrogen

Nitrogen-rich 1,2,4-triazole (1) and 1,2,3-triazole (2) react as bases with the oxygen-rich acids HNO3 (a), HN(NO2)2 (b), and HClO4 (c) to produce energetic salts (1a, 1b, and 1c and 2a, 2b, and 2c, respectively) potentially applicable to composite explosives and propellants. In this study, these salts were studied with the dispersion-corrected density functional theory. For the isomers such as 1a and 2a, the more negative ΔrGm of the formation reaction leads to a higher thermally stable salt. The ability to form intramolecular hydrogen bonds predicted with the quantum theory of atoms in molecules has the order of 2 > 1. Different hydrogen bonds result in different second-order perturbation energies, redshifts in IR, and electron density differences. The charge transfer, binding energy, dispersion energy, lattice energy, and energy gap between frontier orbits in the salts of 1 are larger than those of 2, which is helpful for stabilizing the former, and 1 is more obviously stabilized than 2 by formation of salts. Different conformations of 1 and 2 hardly affect the frontier orbital distributions. Base 1 is a more preferred base than 2 to form salts.

A DFT-D study on the stability and intramolecular interactions of the energetic salts of 3,6-dihydrazido-1,2,4,5-tetrazine

2016 ◽  
Vol 94 (1) ◽  
pp. 28-34
Author(s):  
Xueli Zhang ◽  
Xuedong Gong
Keyword(s):  
Hydrogen Bond ◽  
Density Functional ◽  
Lattice Energy ◽  
Intramolecular Interactions ◽  
Bond Energies ◽  
Dispersion Energy ◽  
Linear Relationships ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bond Energies

Structures of the salts I–IV formed by 3,6-dihydrazido-1,2,4,5-tetrazine with HNO3, HN(NO2)2, HClO4, and HC(NO2)3, respectively, were studied using dispersion-corrected density functional theory. The intramolecular hydrogen bond energies of I–IV were estimated using the quantum theory of atoms in molecules. The total hydrogen bond energies (EH,tot) have the order of I (65.60 kcal/mol) > II (46.24 kcal/mol) > III (39.13 kcal/mol) > IV (19.68 kcal/mol). In addition, the charge transfer (q), binding energy (Eb), lattice energy (HL), dispersion energy (Edis), and second-order perturbation energy (E2) were evaluated for studying the intramolecular interactions between the cation and anion. Linear relationships exist between any two of EH,tot, qtot, Eb, and E2,tot. HLs have the same variation trend as h50s (characteristic height) and may be used as the indicator of impact sensitivity. The HOMOs and LUMOs of I–IV are derived from the HOMOs of the isolated anions and the LUMOs of the isolated cations, respectively. Ultraviolet spectra of I–IV have the strongest absorptions at around 442, 445, 427, and 587 nm, respectively. The excitations HOMO→LUMO to HOMO–7→LUMO play important roles in the first three excited states.

Molecular Investigations of the Newly Synthesized Azomethines as Antioxidants: Theoretical and Experimental Studies

2019 ◽  
Vol 19 (6) ◽  
pp. 419-433 ◽  
Author(s):  
Siyamak Shahab ◽  
Masoome Sheikhi ◽  
Liudmila Filippovich ◽  
Evgenij Dikusar ◽  
Anhelina Pazniak ◽  
...  
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Experimental Studies ◽  
Antioxidant Property ◽  
Nbo Analysis ◽  
Antioxidant Potential ◽  
Functional Theory ◽  
Homo And Lumo ◽  
Intramolecular Hydrogen ◽  
Activity Mechanism

: In this study, the antioxidant property of new synthesized azomethins has been investigated as theoretical and experimental. Methods and Results: Density functional theory (DFT) was employed to investigate the Bond Dissociation Enthalpy (BDE), Mulliken Charges, NBO analysis, Ionization Potential (IP), Electron Affinities (EA), HOMO and LUMO energies, Hardness (η), Softness (S), Electronegativity (µ), Electrophilic Index (ω), Electron Donating Power (ω-), Electron Accepting Power (ω+) and Energy Gap (Eg) in order to deduce scavenging action of the two new synthesized azomethines (FD-1 and FD-2). Spin density calculations and NBO analysis were also carried out to understand the antioxidant activity mechanism. Comparison of BDE of FD-1 and FD-2 indicate the weal antioxidant potential of these structures. Conclusion: FD-1 and FD-2 have very high antioxidant potential due to the planarity and formation of intramolecular hydrogen bonds.

scholarly journals Crystal structure and DFT study of a zinc xanthate complex

2019 ◽  
Vol 75 (11) ◽  
pp. 1582-1585 ◽  
Author(s):  
Adnan M. Qadir ◽  
Sevgi Kansiz ◽  
Necmi Dege ◽  
Georgina M. Rosair ◽  
Igor O. Fritsky
Keyword(s):  
Molecular Structure ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Energy Gap ◽  
Three Dimensional ◽  
Intramolecular Interactions ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo

In the title compound, bis(2-methoxyethyl xanthato-κS)(N,N,N′,N′-tetramethylethylenediamine-κ2 N,N′)zinc(II) acetone hemisolvate, [Zn(C4H7O2S2)2(C6H16N2)]·0.5C3H6O, the ZnII ion is coordinated by two N atoms of the N,N,N′,N′-tetramethylethylenediamine ligand and two S atoms from two 2-methoxyethyl xanthate ligands. The amine ligand is disordered over two orientations and was modelled with refined occupancies of 0.538 (6) and 0.462 (6). The molecular structure features two C—H...O and two C—H...S intramolecular interactions. In the crystal, molecules are linked by weak C—H...O and C—H...S hydrogen bonds, forming a three-dimensional supramolecular architecture. The molecular structure was optimized using density functional theory (DFT) at the B3LYP/6–311 G(d,p) level. The smallest HOMO–LUMO energy gap (3.19 eV) indicates the suitability of this crystal for optoelectronic applications. The molecular electrostatic potential (MEP) further identifies the positive, negative and neutral electrostatic potential regions of the molecules. Half a molecule of disordered acetone was removed with the solvent-mask procedure in OLEX2 [Dolomanov et al. (2009). J. Appl. Cryst. 42, 339–341] and this contribition is included in the formula.

scholarly journals A Density Functional Theory Study on Paracetamol-Oxalic Acid Co-Crystal

2020 ◽  
pp. 11-18
Author(s):  
Punya Paudel ◽  
Krishna Raj Adhikari ◽  
Kapil Adhikari
Keyword(s):  
Density Functional Theory ◽  
Oxalic Acid ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Lattice Energy ◽  
Stable Form ◽  
Functional Theory ◽  
Monoclinic Form ◽  
Hydrogen Bonded

Paracetamol (PCA) has two well-known polymorphic forms, monoclinic (form I) and orthorhombic (form II). The parallel packing of flat hydrogen bonded layers in the metastable form II results in compaction properties superior to the thermodynamic stable form I which contains corrugated hydrogen bonded layers of molecules. In this study, the structure of Paracetamol (PCA)-Oxalic acid (OXA) co-crystal has been analyzed and found layered structure similar to PCA form II which enhance ability to form tablet. The Density Functional Theory (DFT) has been conducted to find some physicochemical properties of co-crystal. It was observed that the lattice energy of co-crystal is more than that of PCA form II showing more stability on co-crystal. The energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO-LUMO gap) in co-crystal was found less than PCA form II showing bigger enhancement of reactivity.

Density functional theory study of the stability of the tetrabutylphosphonium and tetrabutylammonium montmorillonites

Clay Minerals ◽  
2019 ◽  
Vol 54 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Eva Scholtzová ◽  
Daniel Tunega
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Dynamic Properties ◽  
Organic Cations ◽  
Structure Stability ◽  
Functional Theory ◽  
Interatomic Distances ◽  
Principle Density Functional Theory ◽  
The Stability

AbstractThe stability of organoclays prepared from smectites and organic cations depends on the type of used cation, among other factors. This study provides a prediction of the structure, stability and dynamic properties of organoclays based on montmorillonite (Mt) intercalated with two types of organic cations – tetrabutylammonium (TBA) and tetrabutylphosphonium (TBP) – using first-principle density functional theory. The results obtained from simulations were also used in the interpretation of the experimental infrared spectrum of the TBP-Mt organoclay. Analysis of interatomic distances showed that weak C–O···H hydrogen bonds were important in the stabilization of both TBA- and TBP-Mt models, with slightly stronger hydrogen bonds for the TBP cation. Calculated intercalation and adsorption reaction energies (ΔEint//ΔEads*/ΔEads**) confirmed that TBP-Mt structures (–72.4//–32.8/–53.8 kJ/mol) were considerably more stable than TBA-Mt structures (–56.7//–22.6/–37.4 kJ/mol). The stronger interactions of the alkyl chains of the TBP cation with Mt basal surfaces in comparison to those of the TBA cation were also correlated with the positions of the calculated bands of the C–H stretching vibrations.

Stability, Structural and Electronic Properties of Indium Phosphide Wurtzite-Diamantane Molecules and Nanocrystals: A Density Functional Theory Study

2021 ◽  
Vol 69 ◽  
pp. 1-9
Author(s):  
Hamid A. Fayyadh
Keyword(s):  
Density Functional Theory ◽  
Raman Spectrum ◽  
Force Constant ◽  
Density Functional ◽  
Energy Gap ◽  
Spectroscopic Properties ◽  
Functional Theory ◽  
Bulk Energy ◽  
The Stability ◽  
Ir And Raman

The density functional theory is applied for examining the electronic structure and spectroscopic properties for InP wurtzite molecules and nanocrystals. In this paper we present calculations of the energy gap, bond lengths, IR and Raman spectrum, reduced mass and force constant. The results of the presented work showing that the InP’s energy gap was fluctuated about to experimental bulk energy gap (1.49 eV). Results of spectroscopic properties including IR and Raman spectrum, reduced mass and force constant as a function of frequency were in accordance with the provided experimental results. In addition, the study of the Gibbs free energy proved the stability phase of InP wurtzoids against transition to InP diamondoids structure.

Powder X-ray diffraction of pazopanib hydrochloride Form 1, C21H24N7O2SCl

2021 ◽  
pp. 1-3
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Lattice Energy ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Functional Theory ◽  
X Ray

The crystal structure of pazopanib hydrochloride Form 1 has been refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Pazopanib hydrochloride crystallizes in space group P-1 (#2) with a = 8.45008(6), b = 8.71310(12), c = 16.05489(35) Å, α = 79.5996(9), β = 86.4784(5), γ = 87.3764(3)°, V = 1159.724(9) Å3, and Z = 2. The crystal structure is essentially identical to that of CSD Refcode CEVYEK. There are four strong N–H⋯Cl hydrogen bonds to the chloride anion. Several additional weaker N–H⋯Cl and C–H⋯Cl hydrogen bonds are also present. A variety of C–H⋯O, C–H⋯N, and N–H⋯S hydrogen bonds also contribute to the lattice energy. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

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