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.

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 

Spectroscopic investigation of 2-(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)-4H-naphto[2,3-d][1,3]oxazin-4-one molecule

2017 ◽  
Vol 16 (05) ◽  
pp. 1750039
Author(s):  
Yusuf Sert ◽  
Mehmet Gümüş ◽  
Volkan Kamaci ◽  
Halil Gökce ◽  
İbrahim Kani ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Title Compound ◽  
Chemical Shifts ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Distribution Analysis ◽  
Laser Raman ◽  
Laser Raman Spectra ◽  
Software Program ◽  
Lowest Unoccupied Molecular Orbital

In this present study, the experimental and theoretical vibrational frequencies of an important pharmacological molecule 2-(4-benzoyl-1,5-diphenyl-1[Formula: see text]-pyrazol-3-yl)-4[Formula: see text]-naphto[2,3-[Formula: see text]][1,3]oxazin-4-one have been researched. The experimental FT-IR and laser-Raman spectra of the title compound have been taken in the region (4000–400[Formula: see text]cm[Formula: see text]) and (4000–100[Formula: see text]cm[Formula: see text]), respectively. The vibrational modes and optimized structure parameters have been computed by using DFT/B3LYP methods with 6-311[Formula: see text]G(d,p) basis set. In our calculations, Gaussian 09W software program has been used. Assignments of theoretical vibrations have been obtained by potential energy distribution analysis using VEDA 4 software program. This program is important because it performs assignments with 10% precision. We have obtained a fairly good agreement between experimental and theoretically obtained results, and these results have supported the literature. Additionally, we have examined the highest occupied molecular orbital and the lowest unoccupied molecular orbital energies, the other related molecular energy values, nuclear magnetic resonance ([Formula: see text]C and 1H-proton) chemical shifts, and UV–Vis wavelengths (electronic absorption wavelengths of the title compound) by using the mentioned calculation level. The nonlinear optical properties of the title compound have also been determined by using DFT/B3LYP/6-311[Formula: see text]G(d,p) level.

Experimental (FT-IR, Laser-Raman and NMR) and theoretical comparative study on 2-benzylsulfanyl-4-pentyl-6-(phenylsulfanyl)pyrimidine-5-carbonitrile, a potential bioactive agent

2018 ◽  
Vol 17 (05) ◽  
pp. 1850035 ◽  
Author(s):  
Lamya H. Al-Wahaibi ◽  
Nuri Öztürk ◽  
Hanan M. Hassan ◽  
Yusuf Sert ◽  
Ali A. El-Emam ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Chemical Shifts ◽  
Pyrimidine Derivative ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Laser Raman ◽  
Highest Occupied Molecular Orbital ◽  
Laser Raman Spectra ◽  
Lowest Unoccupied Molecular Orbital ◽  
Ft Ir

In this paper, the experimental and theoretical vibrational frequencies of a potential bioactive pyrimidine derivative molecule named 2-benzylsulfanyl-4-pentyl-6-(phenylsulfanyl)pyrimidine-5-carbonitrile has been investigated. The experimental FT-IR and Laser-Raman spectra of the studied molecule are in the region (4000–400[Formula: see text]cm[Formula: see text] and (4000–100[Formula: see text]cm[Formula: see text], respectively, in gas phase. The vibrational modes and optimized ideal structure parameters(bond lengths, bond angles and selected dihedral angles) were calculated by using DFT/B3LYP, DFT/BHandHLYP and DFT/PBE1PBE methods with 6-311[Formula: see text]G(d,p) basis set. The theoretical mode assignments have been obtained by using potential energy distribution (PED) with the VEDA4 software program. Additionally, infrared and Raman intensities, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and their clouds, and other related molecular properties were calculated and evaluated. The proton (1H) and carbon-13 ([Formula: see text]C) nuclear magnetic resonance (NMR) chemical shifts have been investigated for the title molecule, both experimentally (in DMSO-d[Formula: see text] and theoretically (in vacuum and DMSO). The thermodynamic properties of the tile compound have been investigated using the mentioned theoretical computational methods. The results revealed that there isgood agreement between experimental and theoretical results and these results have supported the related literature.

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

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.

scholarly journals Crystal Structure, Hirshfeld Surface and Frontier Molecular Orbital Analyses of N-[2-(trifluoromethyl)phenyl]succinamic Acid

2020 ◽  
Vol 32 (12) ◽  
pp. 3179-3185
Author(s):  
P.A. Suchetan ◽  
S. Naveen ◽  
N.K. Lokanath ◽  
P. Krishna Murthy ◽  
M.V. Deepa Urs
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Orbital ◽  
Density Functional ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Reactivity Descriptors ◽  
Succinamic Acid ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The ortho-CF3 substituent and the N-H bond are in syn-conformation in N-[2-(trifluoromethyl)phenyl]succinamic acid. In amide and acid functionalities, the carbonyl groups are directed in opposite directions to each other and their related-CH2 groups. syn-Conformation is observed for the acid functionality, where the carbonyl C=O and hydroxyl O-H bonds are directed in the same direction. Three planar fragments comprise of the molecule: aromatic ring (A), core portion -Carm-N(H)-C(=O)-C(H2)-C(H2)(B) and -C(H2)-C(=O)-OH(C). The dihedral angle between a pair of fragments being 48.6(4)º (A and B), 81.6 (4)º (B and C) and 70.5 (5)º (A and C). N-H•••O hydrogen bonds bind the molecules forming C(4) chains in the crystal, and the neighbouring anti-parallel chains are bound by O-H•••O hydrogen bonds resulting in a chair shaped ribbon of one-dimensional nature. The Hirshfeld surface study was carried out, including fingerprint plots. Studies have shown that the interactions with O•••H/H•••O (27.4%), H•••H (27.3%) and H•••F/F•••H (20.2%) substantially added to the surface. Theoretically, the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and various global reactivity descriptors were also computed by the density functional theory (DFT/B3LYP) approach with a 6-311G(d, p) basis set in the ground state on the geometrically optimized structure in the gas phase.

scholarly journals Theoretical and X-ray diffraction studies of organic photovoltaic compounds

2014 ◽  
Vol 70 (a1) ◽  
pp. C996-C996
Author(s):  
Abdelkader Chouaih ◽  
Salem Yahiaoui ◽  
Nadia Benhalima ◽  
Manel Boulakoud ◽  
Rachida Rahmani ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Organic Semiconductor ◽  
Density Functional ◽  
Energy Gap ◽  
Three Dimensional ◽  
Basis Set ◽  
X Ray Diffraction ◽  
Hybrid Functional ◽  
X Ray ◽  
Lowest Unoccupied Molecular Orbital

The electronic and structural properties of thiazolic ring derivatives were studied using density functional theory (DFT) and X-ray diffraction in terms of their application as organic semiconductor materials in photovoltaic devices. The B3LYP hybrid functional in combination with Pople type 6-31G(d) basis set with a polarization function was used in order to determine the optimized geometries and the electronic properties of the ground state, while transition energies and excited state properties were obtained from DFT with B3LYP/6-31G(d) calculation. The investigation of thiazolic derivatives formed by the arrangement of several monomeric units revealed that three-dimensional (3D) conjugated architectures present the best geometric and electronic characteristics for use as an organic semiconductor material. The highest occupied molecular orbital (HOMO) . lowest unoccupied molecular orbital (LUMO) energy gap was decreased in 3D structures that extend the absorption spectrum toward longer wavelengths, revealing a feasible intramolecular charge transfer process in these systems. All calculations in this work were performed using the Gaussian 03 W software package.

scholarly journals A Preliminary First Principle Study on Photochromism of Diarylethene Molecules

2019 ◽  
Vol 1 ◽  
pp. 67-77
Author(s):  
Ravi Karki
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Difference ◽  
Basis Set ◽  
Functional Theory ◽  
Solvation State ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Energy Consideration ◽  
Hybrid Density Functional

Photochromism in some diarylethene molecules have been studied by using hybrid density functional theory using the ground state energy consideration. In particular, B3LYP functional and all electron basis set 6-311G (2d,2p) as implemented in Gaussian09 suites of program has been used to investigate the energy difference of two stable isomers of stilbene, azobenzene, cyclooctane, and 1,2, dimethylcyclohexane molecules. The energy difference is corroborated to calculate the frequencies of photons that are required to induce photochromism in these molecules in vacuum and in solvation state. The study found that the molecules exhibit photochromism at various frequency range from infra-red to ultraviolet. The binding energy per atom, charge distribution, HOMO-LUMO (Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital) gap are also calculated for all the molecules in vacuum, water and ethanol solvent. The results obtained are in accordance with the experimental observations.

scholarly journals Comprehensive spectroscopic (FT-IR, FT-Raman, 1H and 13C NMR) identification and computational studies on 1-acetyl-1H-indole-2,3-dione

2017 ◽  
Vol 15 (1) ◽  
pp. 225-237 ◽  
Author(s):  
Maha S. Almutairi ◽  
S. Muthu ◽  
Johanan C. Prasana ◽  
B. Chandralekha ◽  
Alwah R. Al-Ghamdi ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Density Functional ◽  
Energy Gap ◽  
Solid Phase ◽  
Atomic Orbital ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Charge Delocalization ◽  
Ft Ir ◽  
Ft Raman

AbstractFourier transform infrared (FT-IR) and FT-Raman spectra of 1-acetyl-1H-indole-2,3-dione (N-acetylisatin) were recorded in the solid phase and analyzed. The molecular geometry, vibrational frequencies, infrared intensities, Raman activities and atomic charges were calculated using density functional theory (DFT/B3LYP) calculations with a standard 6-311++G(d,p) basis set. The fundamental vibrational modes of N-acetylisatin were analyzed and fully assigned with the aid of the recorded FT-IR and FT-Raman spectra. The simulated FT-IR and FT-Raman spectra showed good agreement with the experimental spectra. The stability of the molecule, arising from hyper-conjugative interactions and charge delocalization, was analyzed using natural bond orbital (NBO) analysis. The dipole moment (µ), polarization (α) and hyperpolarization (β) values of N-acetylisatin were also computed. The potential energy distribution (PED) was computed for the assignment of unambiguous vibrational fundamental modes. The HOMO and LUMO energy gap illustrated the chemical activity of N-acetylisatin. The energy and oscillator strength were calculated by DFT. Gauge–including atomic orbital NMR (1H and 13C) chemical shift calculations were performed and compared with the experimental values. Thermodynamic properties (heat capacity, entropy and enthalpy) of the compound at different temperatures were also calculated.

Structural, QTAIM, thermodynamic properties, bonding, aromaticity and NMR analyses of cation–π interactions of mono and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+, and Ca2+) with substituted pyrazine derivatives

2015 ◽  
Vol 14 (06) ◽  
pp. 1550044 ◽  
Author(s):  
Maryam Zaboli ◽  
Heidar Raissi
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Potential ◽  
Basis Set ◽  
Chemical Hardness ◽  
Aromatic Rings ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Polarized Continuum Model ◽  
Lowest Unoccupied Molecular Orbital

Theoretical investigation of 42 cation-π complexes formed by the alkali metal ( Li +, Na +, K +), alkaline-earth cations ( Be 2+, Mg 2+, Ca 2+) and π-system of the pyrazine and its derivatives have been performed at density functional theory (DFT) (B3LYP functional) and MP2 methods with 6-311++G** basis set in the gas phase and the polarized continuum model (PCM)-water solvation. The following substituents have been taken into consideration: Br , Cl , CH 3, OH , OCH 3 and SH . The interactions present in these complexes have been investigated by means of the natural bond orbital (NBO) and the Bader's quantum theory of atoms in molecules (QTAIMs) approaches. The effects of the interactions on NMR data have been probed using the GIAO-based method to extend investigation of the studied compounds. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies show that charge transfer occurs within each complex. Vibrational frequencies and physical properties such as dipole moment, chemical potential, chemical hardness and chemical electrophilicity of these compounds have been systematically explored. The aromaticity of aromatic rings has been measured using several well-established indices of aromaticity such as nucleus-independent chemical shift, harmonic oscillator models of the aromaticity, para-delocalization index, average two-center indices, aromatic fluctuation index and π-fluctuation aromatic index.

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