Theoretical study, NBO analysis, HOMO/LUMO and first static hyperpolarizability for structural prediction of new ligands 1X-tri-R-σ3λ3-phosphacyclohexadienyl anion using DFT calculations

2020 ◽  
Vol 61 (2) ◽  
Keyword(s):  
Dft Calculations ◽  
Theoretical Study ◽  
Nbo Analysis ◽  
Structural Prediction ◽  
Homo Lumo

scholarly journals THEORETICAL STUDY OF STRUCTURAL GEOMETRY AND ELECTRONIC PROPERTIES OF MAGNESIUM DIBORETH (MgB2)

2019 ◽  
Vol 16 (31) ◽  
pp. 301-307
Author(s):  
Vanessa Mendes MATTJE ◽  
André Rodrigues PINHEIRO ◽  
Douglas Henrique PEREIRA
Keyword(s):  
Electronic Properties ◽  
Theoretical Study ◽  
Electronic Devices ◽  
Nbo Analysis ◽  
Geometric Isomer ◽  
Frontier Molecular Orbital ◽  
Geometric Isomers ◽  
Formation Enthalpies ◽  
Structural And Electronic Properties ◽  
Homo Lumo

The present work made a molecular theoretical study of the structural and electronic properties of the geometric isomers of magnesium diboride (MgB2). The systems have specific characteristics and are very promising for technological applications, such as magnetic resonance imaging devices, motors, and generators. The same is still used in the industries of electronic devices, floating trains (MAGLEV), electricity and Biomagnetism. The results show that the geometric isomer with the lowest energy value is the cyclic species, which is the most stable. The formation enthalpies found were 205.38 Kcal mol-1 and 45.66 Kcal mol-1 for MgB2-cyclic and for B-Mg-B respectively. By means of the analysis Frontier Molecular Orbital it was possible to identify the shape of the HOMO - LUMO orbitals and how they contribute to the ligand and anti-ligand bands and thus to the superconducting properties of the compound. Finally, the NBO analysis confirmed that the most stable geometric isomer is MgB2-cyclic, presenting more interactions between donor or receptor orbitals.

scholarly journals Comparative Theoretical Study of Stability, Lypophilicity, Dipole Moments, Acidity and Spectroscopic Properties of Non-Steroidal Anti-Inflammatory Drugs: Ibuprofen, Ketoprofen and Flurbiprofen

2020 ◽  
pp. 51-60
Author(s):  
Assoma Amon Benjamine ◽  
Atse Adepo Jacques ◽  
Kone Soleymane ◽  
Bamba El Hadji Sawaliho
Keyword(s):  
Dft Calculations ◽  
Physicochemical Properties ◽  
Theoretical Study ◽  
Dipole Moments ◽  
Spectroscopic Properties ◽  
Dft Methods ◽  
Gibbs Energies ◽  
Td Dft ◽  
Inflammatory Drugs ◽  
Homo Lumo

A comparative theoretical study of some physicochemical properties of R and S enantiomers of ibuprofen, ketoprofen and flurbiprofen is undertaken in order to understand their reactivity. To do this, DFT and TD-DFT methods at the B3LYP/6-311G(d,p) level theory are used. The partition coefficient determined is 3.72 for ibuprofen, 2.81 for ketoprofen and 4.12. for flurbiprofen. That means that these NSAIDs are characterized by a high lipophilicity. The calculated Gibbs energies show that the R enantiomer is the most stable in the case of ibuprofen and the S enantiomer in the case of ketoprofen and flurbiprofen. The study of acidity shows that S enantiomer of ibuprofen and R enantiomers of ketoprofen and flurbiprofen are the most acidic enantiomers. TD-DFT calculations show that, the absorption maxima (λmax) of ibuprofen and flurbiprofen correspond to the HOMO→LUMO transition. For ketoprofen, these are associated with the transition HOMO→LUMO+1. These results elucidate the reactivity of the investigated NSAIDs and could help to establish a classification their efficacy.

HUMO-LUMO Studies on Methyl Orange Doped ZTS Crystals for Laser Applications

2018 ◽  
Vol 6 (6) ◽  
pp. 362
Author(s):  
G. Suresh ◽  
K. Sambath Kumar ◽  
P. Ambalavanan ◽  
P. Kumaresan
Keyword(s):  
Molecular Electrostatic Potential ◽  
Nbo Analysis ◽  
Inorganic Materials ◽  
Thermo Gravimetric ◽  
Laser Applications ◽  
Charge Delocalization ◽  
Device Applications ◽  
Warming Rate ◽  
The Stability ◽  
Homo Lumo

Zinc Thiourea Sulphate (ZTS), crystal is a magnificent metal natural compound, which consolidates the upsides of both natural and inorganic materials when contrasted and other customary non-linear optical materials and in this way can be utilized as a part of a more extensive scope of uses. Late endeavors at delivering new recurrence transformation materials have concentrated essentially on expanding the extent of the NLO properties that can recurrence twofold low pinnacle control sources, for example, diode lasers.  The thermo gravimetric examination (TGA) and differential warm investigation (DTA) were completed utilizing Seiko warm analyzer at warming rate 20°C/min in air to decide the warm dependability of the compound. ZTS crystals were developed by moderate cooling procedure. This empowers the development of mass gems along all the three bearings at an ideal pH. FTIR examines demonstrate that in the spectra of ZTS there is a move in the recurrence band in the low-recurrence district which uncovers that thiourea shapes sulfur-to-zinc securities in the ZTS crystals. The stability and charge delocalization of the molecule were also studied by natural bond orbital (NBO) analysis. The HOMO-LUMO energies describe the charge transfer takes place within the molecule. Molecular electrostatic potential has been analyzed.  The developments try in extensive scale with this enhanced pH qualities is required to yield mass crystal appropriate for laser combination tests and SHG device applications.

Density functional theory, Comparative vibrational spectroscopic studies, HOMO-LUMO, and NBO analysis of Trichloro isocyanuric acid and Trithio cyanuric acid

2015 ◽  
Vol 8 (3) ◽  
pp. 2197-2221
Author(s):  
Theraviyum Chithambarathanu ◽  
M. Darathi ◽  
J. DaisyMagdaline ◽  
S. Gunasekaran
Keyword(s):  
Density Functional ◽  
Cyanuric Acid ◽  
Nbo Analysis ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Point Energy ◽  
Isocyanuric Acid ◽  
Ft Ir ◽  
Homo Lumo ◽  
Ft Raman

The molecular vibrations of Trichloro isocyanuric acid (C3Cl3N3O3) and Trithio cyanuric acid (C3H3N3S3) have been investigated in polycrystalline sample at room temperature by Fourier Transform Infrared (FT-IR) and FT-Raman spectroscopies in the region 4000-450 cm-1 and 4000-50 cm-1 respectively, which provide a wealth of structural information about the molecules. The spectra are interpreted with the aid of normal co-ordinate analysis following full structure optimization and force field calculations based on density functional theory   (DFT) using standard B3LYP / 6-311++ G (d, p) basis set for investigating the structural and spectroscopic properties. The vibrational frequencies are calculated and the scaled values are compared with experimental FT-IR and FT-Raman spectra. The scaled theoretical wave numbers shows very good agreement with experimental ones. The complete vibrational assignments are performed on the basis of potential energy distribution (PED) of vibrational modes, calculated with scaled quantum (SQM) method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that change in electron density (ED) in σ* and π* anti-bonding orbitals and second order delocalization   energy (E2) confirm the occurrence of Intra molecular Charge Transfer (ICT) within the molecule. The thermodynamic properties like heat capacity, entropy, enthalpy and zero point energy have been calculated for the molecule. The frontier molecular orbitals have been visualized and the HOMO-LUMO energy gap has been calculated. The Molecular Electrostatic Potential (MEP) analysis reveals the sites for electrophilic attack and nucleophilic reactions in the molecule.

A Theoretical Study of Substituted Stepwise Fluorinated Cyclopropanone Keto-Enol System

2003 ◽  
Vol 58 (12) ◽  
pp. 749-755
Author(s):  
Abdullah El-Alali ◽  
Ali A. Marashdeh ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Isodesmic Reactions ◽  
Orbital Energies ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Complete Optimization

MINDO-Forces calculations have been performed with complete optimization of the geometries on stepwise fluorinated cyclopropanones and their enols. Increase in the number of fluorine atoms causes destabilization of cyclopropanone. Perfluorinated enol was found to be present in substantial concentration, as was mentioned in previous work. This is supported by calculations of Gibbs free energies and isodesmic reactions. Geometrical parameters, heats of formation, electron densities, dipole moments and orbital energies (HOMO-LUMO) are reported.

Sign in / Sign up

Export Citation Format

Share Document