Naphthalene is a simplest polyaromatic hydrocarbon, consist of a fused pair benzene rings which i... more Naphthalene is a simplest polyaromatic hydrocarbon, consist of a fused pair benzene rings which is a white crystalline volatile solid with a characteristic odour of coal-tar and the most familiar household fumigant. Fossil fuels such as petroleum and coal naturally contains naphthalene [1]. Naphthalene and its derivatives are biologically, industrially and pharmaceutically significant compound [2]. Although there are many derivatives in dimethylnaphthalene, one of its derivatives 1,2-dimethylnaphthalene attracts the attention due to its wide applications. It is most commonly used in moth repellents such as moth balls and also used to make tanning agents, resins, lubricants, plastics, antiseptics, toilet deodorants and in other insecticides [3]. Even though 1,2-dimethylnaphthalene has extensive applications, neither quantum chemical calculations nor the vibrational analysis of the compound is reported in the literature, thus we recorded the vibrational spectrum and carried out the quantum chemical computations of 1,2-dimethylnaphthalene. EXPERIMENTAL 1,2-Dimethylnaphthalene was purchased from Sigma-Aldrich Chemicals USA, with a spectroscopic grade (98 %) which was used as such without any further purification.
Abstract:In this work the FT-IR FT-Raman, UV-Visible absorption and 1H NMR spectra of Phthalazine... more Abstract:In this work the FT-IR FT-Raman, UV-Visible absorption and 1H NMR spectra of Phthalazine were registered, assigned and analyzed. The spectra were interpreted with aid of normal coordinate analysis based on DFT/B3LYP and HF methods using standard 6-311++G(d,p) basis set. After scaling there is good agreement between the observed and the calculated frequencies. Bond lengths, angles and dipole moments for the optimized structures of Phthalazine were also calculated. The calculated first order hyperpolarizability shows that the molecule is an attractive molecule for future applications in non linear optics. The calculated Homo-Lumo energies show that charge transfer occurs within the molecule. Mullikan population analysis on atomic charges is also calculated. The study is extended to study the thermodynamic properties of Phthalazine. The 1H nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge independent atomic orbital (GIAO) method and ...
The N-(4-Cholorobenzoyl)Fenamic acid crystal have been grown, the structural and the lattice para... more The N-(4-Cholorobenzoyl)Fenamic acid crystal have been grown, the structural and the lattice parameters are found through XRD analysis. The chemical bonding and their nature analysis was performed from the FTIR and FT-Raman spectra’s. The molecular structure optimized through DFT (Density Functional Theory) computations and correlated through experimental one. From the optimized geometry from the computations provide to the structural, frequencies and other parameters are match with experiments. From hyper-conjugative interactions, charge delocalization used to study the stabile nature of molecules through NBO analysis. The thermodynamic properties are linearly deepened with temperature. And susceptibility of the crystal can be performed is found to decrease at different temperatures is calculated. The spectral analysis agreed well with experiments.
In this work, a combined experimental and theoretical study on molecular structure, vibrational s... more In this work, a combined experimental and theoretical study on molecular structure, vibrational spectra of 1-amino-2,6-dimethylpiperidine (ADP) has been reported. The FTIR and FT-Raman spectrum have been recorded in the region 4000-400 cm -1 and 3500-50 cm -1 , respectively. The molecular geometry, harmonic vibrational frequencies and bonding features of ADP have been calculated by using ab initio /HF and density functional theory/B3LYP methods with 6-31+G(d,p) basis set. A detailed interpretation of the FTIR, FT-Raman, NMR spectra of ADP has also been reported. Natural bond orbital analysis has been carried out to explain the charge transfer or delocalization of charge due to the intra-molecular interactions. Energy of the highest occupied molecular (HOMO) orbital and lowest unoccupied (LUMO) molecular orbital have been predicted.
Quantum chemical calculations of energies, geometrical structures and electronic absorption spect... more Quantum chemical calculations of energies, geometrical structures and electronic absorption spectra of 3,5-diamino-1,2,4-triazole (DAT) were carried out by ab initio HF/6-311+G(d,p), DFT (B3LYP/6-311+G(d,p)). The optimized geometric bond lengths and bond angles obtained by HF method show best agreement with the experimental values. Comparison of the observed fundamental vibrational frequencies of DAT with calculated results by HF and density functional methods indicates that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems. The difference between the observed and scaled wave number values of most of the fundamentals is very small. A detailed interpretation of the FT-IR and FTRaman, NMR spectra of DAT was also reported. Thermodynamic properties were also calculated and discussed. UV– vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time dependent density functional theory...
Solid phase FTIR and FT-Raman spectra of 6-Methyl Quinoline (6MQ) have been recorded in the regio... more Solid phase FTIR and FT-Raman spectra of 6-Methyl Quinoline (6MQ) have been recorded in the region 3400-50 cm-1. The spectra were interpreted with aid of normal coordinate analysis based on DFT using standard B3LYP/6- 311++G (d, p) basis set. After scaling there is good agreement between the observed and the calculated frequencies. The calculated first order hyperpolarizability shows that the molecule is an attractive molecule for future applications in non linear optics. The calculated Homo-Lumo energies show that charge transfer occurs within the molecule. Mullikan population analysis on atomic charges is also calculated. The study is extended to study the thermodynamic properties of 6MQ.
Diphenyl ketone (DPK), a semi-organic nonlinear optical material, has been synthesized and single... more Diphenyl ketone (DPK), a semi-organic nonlinear optical material, has been synthesized and single crystals were grown from alcohol – ethanol solution at room temperature up to dimensions of 4.5cm×4.5cm×4cm. The unit cell parameters were determined from single crystal and powder X-ray diffraction studies. The structural perfection of the grown crystal has been analyzed by X-ray diffraction (XRD) study. The variation of dielectric properties of the grown crystal with respect to frequency has been investigated at different temperatures. Microhardness measurements revealed the mechanical strength of grown crystal. The relative second harmonic efficiency of the compound is found to be 1.4 times greater than that of KDP. And the theoretical studies were conducted on the molecular structure and vibrational spectra of diphenyl ketone (DPK). The FT-IR and FT-Raman spectra of DPK were recorded in the solid phase. The molecular geometry and vibrational frequencies of DPK in the ground state ha...
Solid phase FTIR and FT-Raman spectra of 6-Methyl Q uinoline (6MQ) have been recorded in the regi... more Solid phase FTIR and FT-Raman spectra of 6-Methyl Q uinoline (6MQ) have been recorded in the region 340 0-5 cm. The spectra were interpreted with aid of normal c oordinate analysis based on DFT using standard B3LY P/6311++G (d, p) basis set. After scaling there is goo d agreement between the observed and the calculated frequencies. The calculated first order hyperpolari z bility shows that the molecule is an attractive m olecule for future applications in non linear optics. The calcu lated Homo-Lumo energies show that charge transfer occurs within the molecule. Mullikan population analysis o n atomic charges is also calculated. The study is e xtended to study the thermodynamic properties of 6MQ.
Extensive quantum chemical calculations of energy, geometrical structure, harmonic vibrational fr... more Extensive quantum chemical calculations of energy, geometrical structure, harmonic vibrational frequencies and the construction of theoretical spectrograms of IR and Raman spectra of the molecule, methyl 2,4-dihydroxy-6-methyl benzoate(methyl orsellinate) have been carried out by Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) method with 6311++G(d, p) basis set. The assignments of normal modes of the vibration of the title molecule along with the observed frequencies (FT-IR and FTR) and scaled frequencies have been obtained by HF/DFT computation. The simulated NMR spectra are obtained by (GIAO) gauge independent atomic orbital method and their chemical shifts are compared with the experimental 13 C NMR and 1 H NMR spectra. Molecular geometric parameters, dipole moment, mullikan charge, thermodynamic properties, FMO analysis and NLO properties have also been computed and discussed in a detailed manner.The electrostatic potential surface and the mullikan charge analysis i...
The present work deals the structural and vibrational analysis of Quinoxaline molecule which is p... more The present work deals the structural and vibrational analysis of Quinoxaline molecule which is pharmaceutically and industrially important heterocyclic compound. The FTIR and FT-Raman spectra of Quinoxaline have been measured in the region of 0-3700 cm and UV-Visible spectrum also was recorded. The computations were carried out by employing DFT/B3LYP method with 6-311++G(d,p) basis set. The first order hyperpolarizability and its related properties (α0, μ and ∆α) were also calculated by the finite field approach. The HOMO-LUMO energy gap, chemical hardness, corrosion inhibition were studied. The thermodynamic functions of the title compound have been performed. The observed and calculated wave numbers are found to be in good agreement with the experimental values. The experimental spectra also coincide with the theoretically constructed spectra. From our study we find that the title compound is a good NLO material and posses corrosion inhibition character.
Experimental and computational study of molecular structure, vibrational and UV-spectral analysis... more Experimental and computational study of molecular structure, vibrational and UV-spectral analysis of Hydrazine (1, 3- Dinitrophenyl) (HDP) derivatives. The crystal was grown by slow cooling method and the crystalline perfection of single crystals was evaluated by high resolution X-ray diffractometry (HRXRD) using a multicrystal X–ray diffractometer. Fluorescence, FT-IR and FT-Raman spectra of HDP crystal were recorded. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) followed by scaled quantum force field methodology (SQMFF). NMR studies have confirmed respectively the crystal structure and functional groups of the grown crystal. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) result complements the experimental findings. The calculated MESP, UV, HOMO-LUMO energies show that charge transfer done within the molecule. And various thermodynamic parameters are studied. F...
Asian Journal of Organic & Medicinal Chemistry, 2020
In this work, the geometry optimization and harmonic vibrational wavenumbers of kaempferide (5,7-... more In this work, the geometry optimization and harmonic vibrational wavenumbers of kaempferide (5,7-dihydroxy-4-methoxyflavone) were computed by density functional theory (DFT) method. Theoretically computed vibrational wavenumbers were compared with experimental values and the interpretation of the vibrational spectra has been studied. Frontier molecular orbitals (FMO) and molecular electrostatic potential (MEP) analysis of the title compound have been carried out. The 1H & 13C NMR, UV visible and electronic properties of the compound were investigated theoretically and compared with the experimental values. Molecular docking study of the compound against cytochrome P450 family enzymes (CYPs 1A1, 1A2, 3A4, 2C8, 2C9 and 2D6) were also studied and the results revealed that the title compound interact with human CYP2C8 enzymes with minimum binding energy of -9.43 kcal/mol. The compound forms hydrogen bond with the residues of Thr302, Thr305, Leu361, Val362, Cys435, Gln356 and Ala297. Thu...
International Journal of Research in Engineering and Technology, 2016
The quantum chemical calculations by density functional theory method (DFT) with 6-311G ++(d, p) ... more The quantum chemical calculations by density functional theory method (DFT) with 6-311G ++(d, p) basis set were carried out to compute the parameters such as optimized geometry, dipole moment, mullikan atomic charge, HOMO-LUMO energies, natural bond analysis, polarizability, first order hyperpolarizability and hence non-linear optical properties of 2-aminopyridine, 3-aminopyridine,4-aminopyridine and 3,4-diaminopyridine.Total electron density mapped with molecular electrostatic potential surface, contour map with electrostatic potential surface have been constructed by Gaussian 09W package program to predict the reactive sites in the molecules. The study is extended to determine the thermodynamic properties like total energy, zero point vibrational energy, enthalpy, heat capacity and entropy of the chosen aminopyridines. Correlation fitting equations of thermodynamic properties with respect to temperature were also framed for the chosen molecules from 50K to 1000K.
Systematic interactions of hydrogenated & fluorinated tribromobenzene on Ag and Cu surfaces. Firs... more Systematic interactions of hydrogenated & fluorinated tribromobenzene on Ag and Cu surfaces. First bromine dehalogenation takes place right upon adsorption due to catalytic properties of Ag. Different adsorption geometries of monomers and dimmers of 1,3,5-tribromo-2,4,6-trifluorobenzene(TBFB) and 1,3,5-tribromobenzene(TBB). DFT calculations of the C-Br binding energy dependent on the amount of remaining bromine atoms for both TBFB and TBB were performed. The experiments were performed at low temperature of 80K.STM measurements where performed for of TBFB and TBB. STM show adsorbed molecules in a loose arrangement of molecules. NBO analysis the stability of the molecule arising within hyper-conjugative interactions. The HOMO and LUMO energies and electronic charge transfer (ECT) confirms that electronic transition. High field indicates that this molecule exhibit considerable electrical conductivity in atomic charges.The ESP map is found to be positive within the molecule. The negative charges have a tendency to drift from left to right. The computed thermodynamic parameters like heat capacities (Cº p,m), entropies (Sº m) and enthalpies changes (Hº m) are used for various electrical field.
Quantum chemical calculations of energies, geometrical structure, harmonic vibrational frequencie... more Quantum chemical calculations of energies, geometrical structure, harmonic vibrational frequencies and bonding features in the heterocyclic compounds of 2-amino-4-methylpyridine, 2-amino-4-methylpyrimidine and 2-amino-4-methyltriazine have been carried out by density functional theory (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The theoretical spectrogram for IR and Raman spectra of these compounds have been constructed. The vibrational frequencies are calculated and scaled values are compared with FT-IR experimental values (NIST) of these three compounds. The study is extended to compare and analyze the differences in some of the physical and chemical properties like bond parameters, atomic charges, thermodynamic properties, HOMO-LUMO analysis etc., in the heterocyclic compounds of 2-amino-4-methylpyridine, 2-amino-4-methylpyrimidine and 2-amino-4-methyltriazine using quantum computational methods.
Quinazoline is a compound made up of two fused six member aromatic rings-benzene and pyrimidine r... more Quinazoline is a compound made up of two fused six member aromatic rings-benzene and pyrimidine ring. It is a yellow coloured compound, found usually in crystalline form and it was first prepared by Gabriel in 1903 and first isolated from the Chinese plant Aseru. Quinazoline is the main sixmembered heterocyclic ring system with multiple pharmacophores [1] and notable for their biological activities. The derivatives of this class includes medicines with different biological actions like soporific, sedative, tranquilizing, analgesic, anticonvulsant, antitussive, myorelexant, antirheumatic, hypotensive, antiallergic, bronchodilating, antidiabetic, cholagogue, diuretic, cystatic, antimalarial, spermicidal, etc., [2]. A through literature survey indicates that a complete vibrational analysis of the quinazoline was not been carried so for and the aim of the present investigation is to undertake a complete vibrational and spectroscopic analysis of the quinazoline. The FTIR and FT-Raman spectroscopy combined with quantum chemical computations has been recently used as an effective tool in the vibrational analysis of drug molecules [3], biological compounds [4] and natural products [5].
Naphthalene is a simplest polyaromatic hydrocarbon, consist of a fused pair benzene rings which i... more Naphthalene is a simplest polyaromatic hydrocarbon, consist of a fused pair benzene rings which is a white crystalline volatile solid with a characteristic odour of coal-tar and the most familiar household fumigant. Fossil fuels such as petroleum and coal naturally contains naphthalene [1]. Naphthalene and its derivatives are biologically, industrially and pharmaceutically significant compound [2]. Although there are many derivatives in dimethylnaphthalene, one of its derivatives 1,2-dimethylnaphthalene attracts the attention due to its wide applications. It is most commonly used in moth repellents such as moth balls and also used to make tanning agents, resins, lubricants, plastics, antiseptics, toilet deodorants and in other insecticides [3]. Even though 1,2-dimethylnaphthalene has extensive applications, neither quantum chemical calculations nor the vibrational analysis of the compound is reported in the literature, thus we recorded the vibrational spectrum and carried out the quantum chemical computations of 1,2-dimethylnaphthalene. EXPERIMENTAL 1,2-Dimethylnaphthalene was purchased from Sigma-Aldrich Chemicals USA, with a spectroscopic grade (98 %) which was used as such without any further purification.
Abstract:In this work the FT-IR FT-Raman, UV-Visible absorption and 1H NMR spectra of Phthalazine... more Abstract:In this work the FT-IR FT-Raman, UV-Visible absorption and 1H NMR spectra of Phthalazine were registered, assigned and analyzed. The spectra were interpreted with aid of normal coordinate analysis based on DFT/B3LYP and HF methods using standard 6-311++G(d,p) basis set. After scaling there is good agreement between the observed and the calculated frequencies. Bond lengths, angles and dipole moments for the optimized structures of Phthalazine were also calculated. The calculated first order hyperpolarizability shows that the molecule is an attractive molecule for future applications in non linear optics. The calculated Homo-Lumo energies show that charge transfer occurs within the molecule. Mullikan population analysis on atomic charges is also calculated. The study is extended to study the thermodynamic properties of Phthalazine. The 1H nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge independent atomic orbital (GIAO) method and ...
The N-(4-Cholorobenzoyl)Fenamic acid crystal have been grown, the structural and the lattice para... more The N-(4-Cholorobenzoyl)Fenamic acid crystal have been grown, the structural and the lattice parameters are found through XRD analysis. The chemical bonding and their nature analysis was performed from the FTIR and FT-Raman spectra’s. The molecular structure optimized through DFT (Density Functional Theory) computations and correlated through experimental one. From the optimized geometry from the computations provide to the structural, frequencies and other parameters are match with experiments. From hyper-conjugative interactions, charge delocalization used to study the stabile nature of molecules through NBO analysis. The thermodynamic properties are linearly deepened with temperature. And susceptibility of the crystal can be performed is found to decrease at different temperatures is calculated. The spectral analysis agreed well with experiments.
In this work, a combined experimental and theoretical study on molecular structure, vibrational s... more In this work, a combined experimental and theoretical study on molecular structure, vibrational spectra of 1-amino-2,6-dimethylpiperidine (ADP) has been reported. The FTIR and FT-Raman spectrum have been recorded in the region 4000-400 cm -1 and 3500-50 cm -1 , respectively. The molecular geometry, harmonic vibrational frequencies and bonding features of ADP have been calculated by using ab initio /HF and density functional theory/B3LYP methods with 6-31+G(d,p) basis set. A detailed interpretation of the FTIR, FT-Raman, NMR spectra of ADP has also been reported. Natural bond orbital analysis has been carried out to explain the charge transfer or delocalization of charge due to the intra-molecular interactions. Energy of the highest occupied molecular (HOMO) orbital and lowest unoccupied (LUMO) molecular orbital have been predicted.
Quantum chemical calculations of energies, geometrical structures and electronic absorption spect... more Quantum chemical calculations of energies, geometrical structures and electronic absorption spectra of 3,5-diamino-1,2,4-triazole (DAT) were carried out by ab initio HF/6-311+G(d,p), DFT (B3LYP/6-311+G(d,p)). The optimized geometric bond lengths and bond angles obtained by HF method show best agreement with the experimental values. Comparison of the observed fundamental vibrational frequencies of DAT with calculated results by HF and density functional methods indicates that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems. The difference between the observed and scaled wave number values of most of the fundamentals is very small. A detailed interpretation of the FT-IR and FTRaman, NMR spectra of DAT was also reported. Thermodynamic properties were also calculated and discussed. UV– vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time dependent density functional theory...
Solid phase FTIR and FT-Raman spectra of 6-Methyl Quinoline (6MQ) have been recorded in the regio... more Solid phase FTIR and FT-Raman spectra of 6-Methyl Quinoline (6MQ) have been recorded in the region 3400-50 cm-1. The spectra were interpreted with aid of normal coordinate analysis based on DFT using standard B3LYP/6- 311++G (d, p) basis set. After scaling there is good agreement between the observed and the calculated frequencies. The calculated first order hyperpolarizability shows that the molecule is an attractive molecule for future applications in non linear optics. The calculated Homo-Lumo energies show that charge transfer occurs within the molecule. Mullikan population analysis on atomic charges is also calculated. The study is extended to study the thermodynamic properties of 6MQ.
Diphenyl ketone (DPK), a semi-organic nonlinear optical material, has been synthesized and single... more Diphenyl ketone (DPK), a semi-organic nonlinear optical material, has been synthesized and single crystals were grown from alcohol – ethanol solution at room temperature up to dimensions of 4.5cm×4.5cm×4cm. The unit cell parameters were determined from single crystal and powder X-ray diffraction studies. The structural perfection of the grown crystal has been analyzed by X-ray diffraction (XRD) study. The variation of dielectric properties of the grown crystal with respect to frequency has been investigated at different temperatures. Microhardness measurements revealed the mechanical strength of grown crystal. The relative second harmonic efficiency of the compound is found to be 1.4 times greater than that of KDP. And the theoretical studies were conducted on the molecular structure and vibrational spectra of diphenyl ketone (DPK). The FT-IR and FT-Raman spectra of DPK were recorded in the solid phase. The molecular geometry and vibrational frequencies of DPK in the ground state ha...
Solid phase FTIR and FT-Raman spectra of 6-Methyl Q uinoline (6MQ) have been recorded in the regi... more Solid phase FTIR and FT-Raman spectra of 6-Methyl Q uinoline (6MQ) have been recorded in the region 340 0-5 cm. The spectra were interpreted with aid of normal c oordinate analysis based on DFT using standard B3LY P/6311++G (d, p) basis set. After scaling there is goo d agreement between the observed and the calculated frequencies. The calculated first order hyperpolari z bility shows that the molecule is an attractive m olecule for future applications in non linear optics. The calcu lated Homo-Lumo energies show that charge transfer occurs within the molecule. Mullikan population analysis o n atomic charges is also calculated. The study is e xtended to study the thermodynamic properties of 6MQ.
Extensive quantum chemical calculations of energy, geometrical structure, harmonic vibrational fr... more Extensive quantum chemical calculations of energy, geometrical structure, harmonic vibrational frequencies and the construction of theoretical spectrograms of IR and Raman spectra of the molecule, methyl 2,4-dihydroxy-6-methyl benzoate(methyl orsellinate) have been carried out by Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) method with 6311++G(d, p) basis set. The assignments of normal modes of the vibration of the title molecule along with the observed frequencies (FT-IR and FTR) and scaled frequencies have been obtained by HF/DFT computation. The simulated NMR spectra are obtained by (GIAO) gauge independent atomic orbital method and their chemical shifts are compared with the experimental 13 C NMR and 1 H NMR spectra. Molecular geometric parameters, dipole moment, mullikan charge, thermodynamic properties, FMO analysis and NLO properties have also been computed and discussed in a detailed manner.The electrostatic potential surface and the mullikan charge analysis i...
The present work deals the structural and vibrational analysis of Quinoxaline molecule which is p... more The present work deals the structural and vibrational analysis of Quinoxaline molecule which is pharmaceutically and industrially important heterocyclic compound. The FTIR and FT-Raman spectra of Quinoxaline have been measured in the region of 0-3700 cm and UV-Visible spectrum also was recorded. The computations were carried out by employing DFT/B3LYP method with 6-311++G(d,p) basis set. The first order hyperpolarizability and its related properties (α0, μ and ∆α) were also calculated by the finite field approach. The HOMO-LUMO energy gap, chemical hardness, corrosion inhibition were studied. The thermodynamic functions of the title compound have been performed. The observed and calculated wave numbers are found to be in good agreement with the experimental values. The experimental spectra also coincide with the theoretically constructed spectra. From our study we find that the title compound is a good NLO material and posses corrosion inhibition character.
Experimental and computational study of molecular structure, vibrational and UV-spectral analysis... more Experimental and computational study of molecular structure, vibrational and UV-spectral analysis of Hydrazine (1, 3- Dinitrophenyl) (HDP) derivatives. The crystal was grown by slow cooling method and the crystalline perfection of single crystals was evaluated by high resolution X-ray diffractometry (HRXRD) using a multicrystal X–ray diffractometer. Fluorescence, FT-IR and FT-Raman spectra of HDP crystal were recorded. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) followed by scaled quantum force field methodology (SQMFF). NMR studies have confirmed respectively the crystal structure and functional groups of the grown crystal. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) result complements the experimental findings. The calculated MESP, UV, HOMO-LUMO energies show that charge transfer done within the molecule. And various thermodynamic parameters are studied. F...
Asian Journal of Organic & Medicinal Chemistry, 2020
In this work, the geometry optimization and harmonic vibrational wavenumbers of kaempferide (5,7-... more In this work, the geometry optimization and harmonic vibrational wavenumbers of kaempferide (5,7-dihydroxy-4-methoxyflavone) were computed by density functional theory (DFT) method. Theoretically computed vibrational wavenumbers were compared with experimental values and the interpretation of the vibrational spectra has been studied. Frontier molecular orbitals (FMO) and molecular electrostatic potential (MEP) analysis of the title compound have been carried out. The 1H & 13C NMR, UV visible and electronic properties of the compound were investigated theoretically and compared with the experimental values. Molecular docking study of the compound against cytochrome P450 family enzymes (CYPs 1A1, 1A2, 3A4, 2C8, 2C9 and 2D6) were also studied and the results revealed that the title compound interact with human CYP2C8 enzymes with minimum binding energy of -9.43 kcal/mol. The compound forms hydrogen bond with the residues of Thr302, Thr305, Leu361, Val362, Cys435, Gln356 and Ala297. Thu...
International Journal of Research in Engineering and Technology, 2016
The quantum chemical calculations by density functional theory method (DFT) with 6-311G ++(d, p) ... more The quantum chemical calculations by density functional theory method (DFT) with 6-311G ++(d, p) basis set were carried out to compute the parameters such as optimized geometry, dipole moment, mullikan atomic charge, HOMO-LUMO energies, natural bond analysis, polarizability, first order hyperpolarizability and hence non-linear optical properties of 2-aminopyridine, 3-aminopyridine,4-aminopyridine and 3,4-diaminopyridine.Total electron density mapped with molecular electrostatic potential surface, contour map with electrostatic potential surface have been constructed by Gaussian 09W package program to predict the reactive sites in the molecules. The study is extended to determine the thermodynamic properties like total energy, zero point vibrational energy, enthalpy, heat capacity and entropy of the chosen aminopyridines. Correlation fitting equations of thermodynamic properties with respect to temperature were also framed for the chosen molecules from 50K to 1000K.
Systematic interactions of hydrogenated & fluorinated tribromobenzene on Ag and Cu surfaces. Firs... more Systematic interactions of hydrogenated & fluorinated tribromobenzene on Ag and Cu surfaces. First bromine dehalogenation takes place right upon adsorption due to catalytic properties of Ag. Different adsorption geometries of monomers and dimmers of 1,3,5-tribromo-2,4,6-trifluorobenzene(TBFB) and 1,3,5-tribromobenzene(TBB). DFT calculations of the C-Br binding energy dependent on the amount of remaining bromine atoms for both TBFB and TBB were performed. The experiments were performed at low temperature of 80K.STM measurements where performed for of TBFB and TBB. STM show adsorbed molecules in a loose arrangement of molecules. NBO analysis the stability of the molecule arising within hyper-conjugative interactions. The HOMO and LUMO energies and electronic charge transfer (ECT) confirms that electronic transition. High field indicates that this molecule exhibit considerable electrical conductivity in atomic charges.The ESP map is found to be positive within the molecule. The negative charges have a tendency to drift from left to right. The computed thermodynamic parameters like heat capacities (Cº p,m), entropies (Sº m) and enthalpies changes (Hº m) are used for various electrical field.
Quantum chemical calculations of energies, geometrical structure, harmonic vibrational frequencie... more Quantum chemical calculations of energies, geometrical structure, harmonic vibrational frequencies and bonding features in the heterocyclic compounds of 2-amino-4-methylpyridine, 2-amino-4-methylpyrimidine and 2-amino-4-methyltriazine have been carried out by density functional theory (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The theoretical spectrogram for IR and Raman spectra of these compounds have been constructed. The vibrational frequencies are calculated and scaled values are compared with FT-IR experimental values (NIST) of these three compounds. The study is extended to compare and analyze the differences in some of the physical and chemical properties like bond parameters, atomic charges, thermodynamic properties, HOMO-LUMO analysis etc., in the heterocyclic compounds of 2-amino-4-methylpyridine, 2-amino-4-methylpyrimidine and 2-amino-4-methyltriazine using quantum computational methods.
Quinazoline is a compound made up of two fused six member aromatic rings-benzene and pyrimidine r... more Quinazoline is a compound made up of two fused six member aromatic rings-benzene and pyrimidine ring. It is a yellow coloured compound, found usually in crystalline form and it was first prepared by Gabriel in 1903 and first isolated from the Chinese plant Aseru. Quinazoline is the main sixmembered heterocyclic ring system with multiple pharmacophores [1] and notable for their biological activities. The derivatives of this class includes medicines with different biological actions like soporific, sedative, tranquilizing, analgesic, anticonvulsant, antitussive, myorelexant, antirheumatic, hypotensive, antiallergic, bronchodilating, antidiabetic, cholagogue, diuretic, cystatic, antimalarial, spermicidal, etc., [2]. A through literature survey indicates that a complete vibrational analysis of the quinazoline was not been carried so for and the aim of the present investigation is to undertake a complete vibrational and spectroscopic analysis of the quinazoline. The FTIR and FT-Raman spectroscopy combined with quantum chemical computations has been recently used as an effective tool in the vibrational analysis of drug molecules [3], biological compounds [4] and natural products [5].
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Papers by R Madivanane