scholarly journals Structure, MESP and HOMO-LUMO study of 10-Acetyl- 10H-phenothiazine 5-oxide using vibrational spectroscopy and quantum chemical methods

BIBECHANA ◽  
2012 ◽  
Vol 9 ◽  
pp. 38-49
Author(s):  
Bhawani Datt Joshi ◽  
Poonam Tandon ◽  
Sudha Jain
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Geometry Optimization ◽  
Basis Set ◽  
Orbital Energy ◽  
Potential Energy Distribution ◽  
Hartree Fock ◽  
Quantum Chemical Methods ◽  
B3lyp Method

In this communication, we have presented the geometry optimization, complete vibrational study with potential energy distribution (PED) and frontier orbital energy gap for the 10-Acetyl-10H-phenothiazine 5-oxide (APTZ) molecule using ab initio Hartree-Fock (HF) and density functional theory (DFT/B3LYP) method employing 6-311++G(d,p) basis set. The calculated IR and Raman spectra with their intensities, molecular electrostatic potential (MESP) surface and highest occupied molecular orbital (HOMO) - lowest unoccupied molecular orbital (LUMO) plot have been given. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7151 BIBECHANA 9 (2013) 38-49

scholarly journals Structure, Electronic And Vibrational Study of 7-Methyl-2,3-Dihydro-(1,3)Thiazolo(3,2-A) Pyrimidin-5-One by Using Density Functional Theory

2018 ◽  
Vol 22 (2) ◽  
pp. 1-11
Author(s):  
Bhawani Datt Joshi ◽  
Janga Bahadur Khadka ◽  
Atamram Bhatt
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Basis Set ◽  
Orbital Energy ◽  
Potential Energy Distribution ◽  
Functional Theory ◽  
Hartree Fock ◽  
Solvent Phase ◽  
Lowest Unoccupied Molecular Orbital

 We have presented molecular structure and vibrational wavenumber assignments of 7-methyl-2,3-dihydro-(1,3)thiazolo(3,2-a)pyrimidin-5-one. Both ab initio Hartree-Fock and density functional theory employing 6-311++G(d,p) basis set have been used for the calculations. The scaled values of the calculated vibrational frequencies were used for assignments on the basis of potential energy distribution. The structure-activity relation has been interpreted by mapping molecular electrostatic potential surface. Electronic properties have been analyzed by using time dependent density functional theory (TD-DFT) for both gaseous and solvent phase. The calculated HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy values show that the charge transfer occurs within the molecule. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, Page: 1-11 

Density Functional Study on the Configurations of Nen (n=2~36) Clusters

2017 ◽  
Vol 727 ◽  
pp. 381-387
Author(s):  
Chang Ning Peng ◽  
Xing Rong Zheng
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Energy Gap ◽  
Geometry Optimization ◽  
Basis Set ◽  
Functional Study ◽  
B3lyp Method ◽  
The Density Functional Theory ◽  
Quantum Chemistry Calculations ◽  
Average Bond

Based on the First-principles and the method of quantum chemistry calculations, using the B3LYP method and 6-31G basis set of the density functional theory (DFT), the configurations and binding energy of Nen (n=2~36) clusters are calculated and studied theoretically after the calculation of geometry optimization. By changing the atomic number n of the Nen (n=2~36) clusters, it obtained that the stable structures, the binding energy and HOMO - LUMO energy gap of the Nen (n=2~36) clusters under the same ideal conditions, and summarizes the change rule of the stable configurations, the binding energy and the average bond length of the Nen (n=2~36) clusters.

scholarly journals Spectroscopic Investigations and DFT Calculations on 3-(Diacetylamino)-2-ethyl-3H-quinazolin-4-one

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Yusuf Sert ◽  
Fatih Ucun ◽  
Gamal A. El-Hiti ◽  
Keith Smith ◽  
Amany S. Hegazy
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Solid Phase ◽  
Vibrational Frequencies ◽  
Geometric Parameters ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Laser Raman ◽  
Quantum Chemical Methods ◽  
Lowest Unoccupied Molecular Orbital

The theoretical and experimental vibrational frequencies of 3-(diacetylamino)-2-ethyl-3H-quinazolin-4-one (2) were investigated. The experimental Laser-Raman spectrum (4000–100 cm−1) and FT-IR spectrum (4000–400 cm−1) of the newly synthesized compound were recorded in the solid phase. Both the theoretical vibrational frequencies and the optimized geometric parameters such as bond lengths and bond angles have for the first time been calculated using density functional theory (DFT/B3LYP and DFT/M06-2X) quantum chemical methods with the 6-311++G(d,p) basis set using Gaussian 03 software. The vibrational frequencies were assigned with the help of potential energy distribution (PED) analysis using VEDA 4 software. The calculated vibrational frequencies and the optimized geometric parameters were found to be in good agreement with the corresponding reported experimental data. Also, the energies of the lowest unoccupied molecular orbital (LUMO), highest occupied molecular orbital (HOMO), and other related molecular energies for 3-(diacetylamino)-2-ethyl-3H-quinazolin-4-one (2) have been investigated using the same computational methods.

Revealing the Inhibition Efficiencies of Artesunate and Rutin for Corrosion of Steel: A Theoretical Study

2018 ◽  
Vol 762 ◽  
pp. 325-329 ◽  
Author(s):  
Gökhan Gece
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Theoretical Calculations ◽  
Aqueous Media ◽  
Basis Set ◽  
Orbital Energy ◽  
Molecular Orbital Energy ◽  
Experimental Findings ◽  
Corrosion Of Steel

Corrosion inhibition characteristics of artesunate and rutin on carbon steel in water has been studied using density functional theory (DFT). Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (ΔE), and global reactivity properties have been calculated at the B3LYP/6-311G(d,p) basis set. The results of theoretical calculations confirm the experimental findings on the superiority of rutin to protect the corrosion of steel in aqueous media compared to artesunate.

scholarly journals Synthesis, characterization, DFT, and TD-DFT studies of (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite)

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Hitler Louis ◽  
Obieze C. Enudi ◽  
Joseph O. Odey ◽  
Izubundu B. Onyebuenyi ◽  
Azuaga T. Igbalagh ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Nbo Analysis ◽  
Basis Set ◽  
Orbital Interactions ◽  
B3lyp Method ◽  
Td Dft ◽  
Donor Acceptor ◽  
Molecular Orbital Analysis

AbstractIn this study, (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite), a cyanurated H-acid (CHA) azo dye, was synthesized and characterized using FT-IR spectrophotometer and GC-MS spectroscopy. A density functional theory (DFT) based B3LYP and CAM-B3LYP method with 6–311 + G (d,p) basis set analysis was computed for HOMO-LUMO, natural bonding orbitals (NBO), UV-Vis absorptions and excitation interactions, in order to understand its molecular orbital excitation properties. A low Energy gap (Eg) of 2.947 eV was obtained from the molecular orbital analysis, which showed that HOMO to LUMO transition is highly feasible; hence CHA is adequate for diverse electronic and optic applications. Studies of the first five excitations (S0 → S1/S2/S3/S4/S5) of CHA revealed that S0 → S1 and S0 → S3 are π → π* type local excitations distributed around the –N=N– group; S0 → S2, a Rydberg type local excitation; S0 → S4, a highly localized π → π* excitation; while S0 → S5 is an n → π* charge transfer from a benzene ring to –N=N– group. From NBO analysis, we obtained the various donor–acceptor orbital interactions contributing to the stabilization of the studied compound. Most significantly, some strong hyper-conjugations (n → n*) within fragments, and non-bondingand anti-bonding intermolecular (n → n*/π* and π → n*/π*) interactions were observed to contribute appreciable energies. This study is valuable for understanding the molecular properties of the azo dyes compounds and for synthesizing new ones in the future.

A Theoretical Investigation of Some N-Hydroxymethyl Amino Acids as Corrosion Inhibitors for Mild Steel

2019 ◽  
Vol 800 ◽  
pp. 108-112 ◽  
Author(s):  
Emre Özdemir ◽  
Gökhan Gece
Keyword(s):  
Amino Acids ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Calculated Data ◽  
Basis Set ◽  
Orbital Energy ◽  
Simple Relationship ◽  
Molecular Orbital Energy ◽  
Microbial Effects

In this study, the dependence of corrosion inhibition and microbial effects of four N-hydroxymethylated amino acids, on their molecular and electronic structure is analyzed using density functional theory calculations. Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (ΔE) were calculated at the B3LYP/6-311G++(d,p) basis set. Although no simple relationship between the inhibition performance and the calculated data could be discerned, the comparison of inactivation rate constants with energetic parameters suggested that microbial effects of the compounds can be explained in terms of their side chain disparities.

scholarly journals Computational Studies of Diindole-Based Molecules for Organic Bulk Heterojunction Solar Devices Using DFT and TD-DFT Calculations

2021 ◽  
Author(s):  
Elly Tan Li Fei ◽  
Joydeep Biswas ◽  
Bandita Datta ◽  
Dhruva Kumar
Keyword(s):  
Dft Calculations ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Bulk Heterojunction ◽  
Acid Methyl Ester ◽  
Basis Set ◽  
Orbital Energy ◽  
Photovoltaic Properties ◽  
Td Dft

Abstract Theoretical analysis on geometries, optoelectronic properties, photovoltaic properties and absorption spectra on six π-conjugated molecules used in organic bulk heterojunction solar cell (BHJ), completed using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations with Becke’s three-parameter functional and Lee-Yang-Parr functional (B3LYP), hybrid exchange-correlation functional using the Coulomb-attenuating method (CAM-B3LYP) and WB97XD level with 6-311G basis set supported by Gauss View and Gaussian 09 program. LUMO (lowest unoccupied molecular orbital), HOMO (highest occupied molecular orbital), energy gap (Egap) and Voc (open-circuit voltage) and other essential parameters have been investigated to study the effects on substitution of electron-donating and electron-accepting groups to the proposed molecule. These properties determine if the studied compounds can act as good electron donors along with phenyl-C61-butyric acid methyl ester (PCBM) as a suitable electron acceptor.

scholarly journals Estudo teórico da eficiência de inibidores orgânicos de corrosão derivados do benzimidazol

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Frederico Marcondes Da Silva ◽  
Lillian Weitzel Coelho Paes
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Orbital Energy ◽  
Molecular Orbital Energy ◽  
Highest Occupied Molecular Orbital ◽  
Fukui Indices ◽  
Lowest Unoccupied Molecular Orbital ◽  
Quantum Parameters

The objective of this work was to evaluate the efficiency of inhibition the corrosion of two organic molecules derived from benzimidazole, specifically 2-mercaptobenzimidazole (2Mcb) and 2-phenylbenzimidazole (2Fb). The calculations were performed using the Density Functional Theory (DFT) at the B3LYP with 6-311+G(d,p) basis set. The quantum parameters correlated with the inhibition efficiency such as the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO) , energy gap (ΔE), electronegativity (χ), hardness (η), the fractions of electrons transferred (ΔN), electrophilicity (ω) and Fukui indices, were calculated. Calculations were performed in aqueous medium in both protonated and non-protonated forms. Theoretical results were compared with experimental data and a good correlation was found between the chemical quantum parameters and the efficiency of inhibition of the molecules. DOI: http://dx.doi.org/10.30609/JETI.2018-5270

SPECTROSCOPIC STUDY, NLO PROPERTIES AND HOMO–LUMO ANALYSIS ON DIFFERENT DONOR AND ACCEPTOR SUBSTITUENTS OF THIAZOLYLAZOPYRIMIDINE CHROMOPHORES

2013 ◽  
Vol 12 (05) ◽  
pp. 1350039 ◽  
Author(s):  
ÖMER TAMER ◽  
DAVUT AVCI ◽  
YUSUF ATALAY
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Atomic Orbital ◽  
Geometry Optimization ◽  
Vibrational Frequencies ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Potential Energy Distribution ◽  
Donor And Acceptor ◽  
The Mean

The molecular geometry optimization, vibrational frequencies and gauge including atomic orbital (GIAO) 1H and 13C chemical shift values of thiazolylazopyrimidine chromophores have been investigated by using density functional theories (DFT/B3LYP, PBE1PBE and BHand-HLYP) and Hartree–Fock (HF) methods with 6–31++G(d,p) basis set. The computed IR and NMR spectra are used to determine the types of the experimental bands observed. Also, the vibrational frequencies are supported on the basis of the potential energy distribution (PED) analysis calculated by using PBE1PBE method. The UV-vis spectrum has been obtained by TD-DFT and TD-HF methods. Total static dipole moment (μ), the mean polarizability (〈α〉), the anisotropy of the polarizability (Δα), the mean first-order hyperpolarizability (〈β〉), highest occupied molecular orbital (HOMO), and lowest occupied molecular orbital (LUMO) energies of thiazolylazopyrimidine chromophores also have been investigated with quantum chemical calculations. Obtained nonlinear optical (NLO) parameters are compared with experimental ones. Additionally, the molecular hardness (η) and electronegativity (χ) parameters have been obtained by using the frontier molecular orbital energies. Obtained data from thiazolylazopyrimidine chromophores are important for associating the experimental and theoretical spectra with molecular structure and their properties.

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.

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