Investigating the Effect of Nitro Groups on the Electronic Properties of Phenanthrene Compound

2021 ◽  
Vol 14 (3) ◽  
pp. 221-230
Keyword(s):  
Fermi Level ◽  
Electronic Properties ◽  
Ionization Potential ◽  
Nitro Group ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Potential Surfaces ◽  
Homo And Lumo ◽  
Total Energies

Abstract: Theoretical study for calculating the electronic structure of phenanthrene compound and its simplest derivatives with nitro groups in different positions was performed using density functional theory (DFT) based on the hybrid function of three parameters. Lee-Yang-Parr [B3LYP] with 6-31 [d, p] basis set was used to investigate the effect of nitro groups on the electronic properties of phenanthrene compound. All calculations were obtaind by employing the used method using the Gaussian 09 package of programs. The energy gaps, total energies, the energy of HOMO and LUMO, softness, dipole moment, Fermi level, molecular symmetry, electrochemical hardness, electron density, electrostatic potential surfaces and infrared spectra were calculated. The results showed that the electronic properties of phenanthrene molecule are affected by the added nitro group. The total energy, energy gap and the HOMO and LUMO energy decreased compared with the original molecule. The ionization potential (IP), electron affinity (EA) and Fermi level (Ef) are increased compared with the original molecule. Keywords: B3LYP/DFT calculations, Phenanthrene molecule, Nitro group, Energy gap, Ionization potential.

Spectroscopic investigations and DFT studies of synthesized 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate a novel conjugate of gallic acid

2020 ◽  
Vol 17 ◽  
Author(s):  
Sangeeta Srivastava ◽  
Nadeem Ahmad Ansari ◽  
Sadaf Aleem
Keyword(s):  
Gallic Acid ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Major Constituent ◽  
Orbital Energy ◽  
Reactivity Descriptors ◽  
Homo And Lumo ◽  
Electrophilic Reactivity ◽  
Global And Local

: Gallic acid is abundantly found in amla (Phyllanthus emblica), a deciduous of the family phyllanthaceae. Gallic acid, the major constituent of the plant was methylated to 3,4,5 trimethoxy gallic acid, which then underwent steglich esterification first with paracetamol and then with 4-hydroxy acetophenone to yield 4-acetamidophenyl 3,4,5-trimethoxybenzoate and 4-acetyl phenyl 3,4,5-trimethoxybenzoate “respectively”. 1H NMR, 13C NMR, UV, FT-IR and mass spectroscopy were used to characterize the synthesized compounds. Density functional theory (B3YLP) using 6-31G (d,p) basis set have been used for quantum chemical calculations. AIM (Atom in molecule) approach depicted weak molecular interactions within the molecules whereas the reactive site and reactivity within the molecule were examined by global and local reactivity descriptors. The HOMO and LUMO energies and frontier orbital energy gap were calculated by time dependant DFT approach using IEFPCM model. Small value for HOMO–LUMO energy gap indicated that easier charge transfer occurs within compound 4. The nucleophilic and electrophilic reactivity were determined by MEP (molecular electrostatic potential) experiment. Polarizability, dipole moment, and first hyperpolarizability values were calculated to depict the NLO (nonlinear optical) property of both the synthesized compounds. The antimicrobial activity was also carried out and broad spectrum antibacterial activity against several strains of bacteria and certain unicellular fungi were exhibited by synthesized compound 3.

STRUCTURAL AND ELECTRONIC PROPERTIES OF FINITE-LENGTH SINGLE-WALLED CARBON AND SILICON CARBIDE NANOTUBES: DFT STUDY

2013 ◽  
Vol 27 (29) ◽  
pp. 1350210 ◽  
Author(s):  
IGOR K. PETRUSHENKO ◽  
NIKOLAY A. IVANOV
Keyword(s):  
Silicon Carbide ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Functional Theory ◽  
Single Walled Carbon ◽  
Silicon Carbide Nanotubes ◽  
Structural And Electronic Properties ◽  
Walled Carbon Nanotubes

This paper presents a systematical analysis of the structure and electronic properties of armchair single-walled carbon nanotubes (SWCNTs) as well as single-walled silicon carbide nanotubes ( SiCNTs ) by using density functional theory. The geometries of all species were optimized at the B3LYP level of theory using the SVP basis set. The different behavior of C – C bonds "parallel" and "perpendicular" to the nanotube axis has been found. The HOMO–LUMO energy gap, ionization potential, electron affinity, electronegativity and hardness of studied tubes were compared. The influence of both SWCNTs and SiCNTs lengths on their electronic properties has been analyzed.

scholarly journals (E)-1-(Benzo[d][1,3]dioxol-5-yl)-3-([2,2′-bithiophen]-5-yl)prop-2-en-1-one: crystal structure, UV–Vis analysis and theoretical studies of a new π-conjugated chalcone

2019 ◽  
Vol 75 (5) ◽  
pp. 632-637
Author(s):  
Ainizatul Husna Anizaim ◽  
Muhamad Fikri Zaini ◽  
Muhammad Adlan Laruna ◽  
Ibrahim Abdul Razak ◽  
Suhana Arshad
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Weak Interactions ◽  
Basis Set ◽  
Molecular Orbital Calculations ◽  
Functional Theory ◽  
Compound C ◽  
Homo And Lumo ◽  
Experimental Values ◽  
Homo Lumo

In the title compound, C18H12O3S2, synthesized by the Claisen–Schmidt condensation method, the essentially planar chalcone unit adopts an s-cis configuration with respect to the carbonyl group within the ethylenic bridge. In the crystal, weak C—H...π interactions connect the molecules into zigzag chains along the b-axis direction. The molecular structure was optimized geometrically using Density Functional Theory (DFT) calculations at the B3LYP/6–311 G++(d,p) basis set level and compared with the experimental values. Molecular orbital calculations providing electron-density plots of HOMO and LUMO molecular orbitals and molecular electrostatic potentials (MEP) were also computed both with the DFT/B3LYP/6–311 G++(d,p) basis set. The experimental energy gap is 3.18 eV, whereas the theoretical HOMO–LUMO energy gap value is 2.73 eV. Hirshfeld surface analysis was used to further investigate the weak interactions present.

scholarly journals Molecular modelling, spectroscopic characterization and nonlinear optical analysis on N-Acetyl-DL-methionine

2020 ◽  
Vol 66 (6 Nov-Dec) ◽  
pp. 749
Author(s):  
N. Günay ◽  
Ö. Tamer ◽  
D. Avcı ◽  
E. Tarcan ◽  
Y. Atalay
Keyword(s):  
Electronic Properties ◽  
Title Compound ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Spectroscopic Characterization ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Molecular Electrostatic Potential Surface ◽  
Experimental Values

In this present methodical study, on the basis of the density functional theory (DFT), the first-principles calculations have been employed successfully to study the structural and electronic properties of N-acetyl-DL-methionine (C7H13NO3S) which is a derivative of DL-methionine which is also known DL-2-amino-4-methyl-thiobutanoic acid. Optimized molecular structure, vibrational frequencies and also 13C and 1H NMR chemical shift values of the title compound are provided in a detailed manner by using B3LYP and HSEH1PBE functionals by applying 6-311++G(d,p) basis set for calculations using Gaussian 09W program. The comparison of the calculated values with the experimental values provides important information about the title compound. In addition, the electronic properties (UV-Vis calculations) of the title compound, such as HOMO-LUMO energy values and energy gap, absorption wavelengths, oscillator strengths were performed basing on the optimized structure in gas phase. Moreover, the molecular electrostatic potential surface, dipole moment, nonlinear optical properties, linear polarizabilities and first hyperpolarizabilities and chemical parameters have also been studied.

scholarly journals Investigation of The Influence of Halogens, Cycloalkanes, Carbonyls and the Hydroxyl Groups on The Reactivity of 1, 3-Butadienes With Imine Dienophile: Insight From DFT, MEDT, and QTAIM

2021 ◽  
Author(s):  
Fredrick Asogwa ◽  
Hitler Louis ◽  
Dollars I. Kenthurky ◽  
Obieze C. Enudi
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Biological Activities ◽  
Diels Alder ◽  
Basis Set ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Free Energy Of Activation ◽  
Homo And Lumo ◽  
Gibb’S Free Energy

Abstract The presence of nitrogen atom either on the diene or the dienophile structure gives rise to aza or imino-Diels-Alder reactions (DARs). Among hetero-DARs, imino-dienophiles yields numerous functionalized compounds with numerous biological activities including but not limited to antifungal, antibacterial and enzymatic properties. Density functional theory (DFT) using the B3LYP functional at the 6-31+G (d, p) basis set along with topological studies (QTAIM) were used for the investigation of 10 different (SD1-SD10) DARs which differ in the nature of substituents groups attached to the diene molecule. The study indicates higher electron density and stronger interaction for substituted dienes with the cycloalkanes, furan, carbonyl, and -OH groups. It was observed in the HOMO-LUMO energy differences that the bulky groups; SD3, SD4, and SD6 had destabilization energy of -7.86 and 0.09, -7.88 and 0.10 and -7.50 and -0.014 eV respectively in their HOMO and LUMO levels while the halogen substituted dienes SD1, SD2, and SD5 had -8.20 and -0.32, -8.31 and -0.34 and -8.19 and -0.20 eV respectively. The study showed that synthesis of hetero-nuclear aza-cyclohexene is achieved faster with furan substituent of energy gap 7.534 eV and molecular hardness of 3.677 compared to 7.799 (SD7) -8.100 eV (SD8) and 3.899 (SD7) - 4.050 (SD8) respectively scored by other substituents noting that smaller energy gap leads to higher reactivity. HCOCH3 (SD8) retarded the rate of the reaction by about 58% (unspontaneous) following the calculated Gibb’s free energy of activation while SD6 in the ELF analysis showed complete covalent character against other cycloalkanes that showed dual characteristics of a double and single bond between N-C at their transition states.

scholarly journals Comparative DFT Study of Phytochemical Constituents of the Fruits of Cucumis trigonus Roxb. and Cucumis sativus Linn.

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Subarayan Bothi Gopalakrishnan ◽  
Thangaraj Kalaiarasi ◽  
Ramasamy Subramanian
Keyword(s):  
Cucumis Sativus ◽  
Density Functional ◽  
Energy Gap ◽  
Effective Properties ◽  
Chemical Reactivity ◽  
Basis Set ◽  
The Density Functional Theory ◽  
Homo And Lumo ◽  
Phytochemical Constituents ◽  
Effective Drugs

The hepatoprotective active phytochemical constituents from the ethanolic extracts of the fruits of Cucumis trigonus Roxb. and Cucumis sativus Linn. were identified by GC-MS analysis. The density functional theory (DFT) of these molecules was calculated by density functional B3LYP methods using B3LYP/6-311++G(d,p) basis set. The optimized geometries of phytochemical constituents were evaluated. Physicochemical properties such as HOMO, LUMO, ionization potential, electron affinity, electronegativity, electrochemical potential, hardness, softness, electrophilicity, total energy, and dipole moment have also been recorded. These are very important parameters to understand the chemical reactivity and biological activity of the phytochemical constituents. Glycodeoxycholic acid and 2-(2-methylcyclohexylidene)-hydrazinecarboxamide were found to be effective drugs selected on the basis of their HOMO and LUMO energy gap and softness. The effective properties of these compounds may be due to the presence of amino, carbonyl, and alcohol as a functional group.

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.

Theoretical investigation on tautomerism and NLO properties of Salicylideneaniline derivatives

2021 ◽  
Author(s):  
N. Daho ◽  
N. Benhalima ◽  
F. KHELFAOUI ◽  
O. SADOUKI ◽  
M. Elkeurti ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Intramolecular Proton Transfer ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Visible Absorption ◽  
Charge Delocalization ◽  
Intramolecular Hydrogen

In this work, a comprehensive investigation of the salicylideneaniline derivatives is carried out using density functional theory to determine their linear and non-linear optical properties. Geometry optimizations, for gas and solvent phases, of the tautomers (enol and keto forms) are calculated using B3LYP levels with 6–31G (d,p) basis set . An intramolecular proton transfer, for 1SA-E and 2SA-E, is performed by a PES scan process at the B3LYP/6-31G (d,p) level. The optical properties are determined and show that they have extremely high nonlinear optical properties. In addition, the RDG analysis, MEP, and gap energy are calculated. The low energy gap value indicates the possibility of intramolecular charge transfer. The frontier molecular orbital calculations clearly show the inverse relationship of HOMO–LUMO gap with the first-order hyperpolarizability (β = 59.6471 × 10-30 esu), confirming that the salicylideneaniline derivatives can be used as attractive future NLO materials. Therefore, the reactive sites are predicted using MEP and the visible absorption maxima are analyzed using a theoretical UV–Vis spectrum. Natural bond orbitals are used to investigate the stability, charge delocalization, and intramolecular hydrogen bond.

scholarly journals Theoretical Study of Solvent Effects on the Electronic and Thermodynamic Properties of Tetrathiafulvalene (TTF) Molecule Based on DFT

2021 ◽  
pp. 42-54
Author(s):  
Rabiu Nuhu Muhammad ◽  
N. M. Mahraz ◽  
A. S Gidado ◽  
A. Musa
Keyword(s):  
Thermodynamic Properties ◽  
Bond Length ◽  
Density Functional ◽  
Theoretical Study ◽  
Energy Gap ◽  
Basis Set ◽  
Basis Sets ◽  
Frontier Molecular Orbital ◽  
Orbital Energy ◽  
Chemical Hardness

Tetrathiafulvalene () is an organosulfur compound used in the production of molecular devices such as switches, sensors, nonlinear optical devices and rectifiers. In this work, a theoretical study on the effects of solvent on TTF molecule was investigated and reported based on Density Functional Theory (DFT) as implemented in Gaussian 03 package using B3LYP/6-31++G(d,p) basis set. Different solvents were introduced as a bridge to investigate their effects on the electronic structure. The HUMO, LUMO, energy gap, global chemical index, thermodynamic properties, NLO and DOS analysis of the TTF molecule in order to determine the reactivity and stability of the molecule were obtained. The results obtained showed that the solvents have effects on the electronic and non-linear-optical properties of the molecule. The optimized bond length revealed that the molecule has strong bond in gas phase with smallest bond length of about 1.0834Å than in the rest of the solvents. It was observed that the molecule is more stable in acetonitrile with HOMO-LUMO gap and chemical hardness of 3.6373eV and 1.8187eV respectively. This indicates that the energy gap and chemical hardness of TTF molecule increases with the increase in polarity and dielectric constant of the solvents. The computed results agreed with the results in the literature. The thermodynamics and NLO properties calculation also indicated that TTF molecule has highest value of specific heat capacity (Cv), total dipole moment () and first order hyperpolarizability () in acetonitrile, while acetone has the highest value of entropy and toluene has a slightly higher value of zero point vibrational energy (ZPVE) than the rest of the solvents. The results show that careful selection of the solvents and basis sets can tune the frontier molecular orbital energy gap of the molecule and can be used for molecular device applications.

scholarly journals Spectroscopic and Electrochemical Investigations of New 5-oxo-2- Phenyloxazol-4(5H)-ylidene Based Triazine Derivatives

2019 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Electronic Absorption Spectra ◽  
Spectroscopic Properties ◽  
Functional Theory ◽  
Structural Framework ◽  
Triazine Derivatives ◽  
Homo And Lumo ◽  
Cyclic Voltammetry Analysis ◽  
Oxazolone Ring

The present study reports the two step synthesis of a novel oxazolone derivative, 4-((4,6-bis(4-((Z)-(5-oxo-2-phenyloxazol-4(5H)-ylidene) methyl)phenoxy)-1,3,5-triazin-2-yl) oxy) benzaldehyde (CBOZ (5)), containing two oxazolone ring substituted with central triazine nucleus in their structural framework. The structural and spectroscopic properties of synthesized CBOZ (5) were characterized by FTIR, 1HNMR, 13CNMR, and mass spectroscopic analysis. The UV-Vis absorption of CBOZ (5) showed a single absorption band at ~370 nm due to π-π* transition with the estimated energy gap of ~3.02 eV. Cyclic voltammetry analysis revealed that the synthesized CBOZ (5) obtained the HOMO and LUMO values of -5.87 eV and-2.85 eV, respectively. Density functional theory (DFT) studies were carried out to predict the electronic absorption spectra of CBOZ (5) and the obtained values were in excellent agreement with the experimental results.

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