Molecular structure, vibrational spectra and nonlinear optical properties of orthoarsenic acid–tris-(hydroxymethyl)-aminomethane DFT study (original) (raw)
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Asian Journal of Chemistry, 2016
In the present work, the ultraviolet absorption spectrum of 2-amino-4,6-dimethylpyridine has been carried out experimentally (in water, n-hexane, ethanol, methanol and MgO) and theoretically (in water, ethanol and methanol) in the range 3500-2300 cm-1 in the solution phase. Predicted electronic absorption spectra from time dependent density functional theory (TD-DFT) calculation have been analyzed and compared with the experimental UV-visible spectrum. The effects of amino and methyl group substituent in pyridine ring have been analyzed. The electronic properties such as excitation energy, wavelength corresponding to absorption maxima (λmax), oscillator strength (f), HOMO and LUMO energies are calculated by time-dependent density functional theory (TD-DFT) using HF/6-311++G(d,p) and B3LYP/6-311++G(d,p) as basis sets. The electric dipole moment (µ), polarizability (α) and the first hyperpolarizability (β) have been computed to evaluate the non-linear optical (NLO) response 2-amino-4,6-dimethylpyridine by Hartee-Fock (HF) and density functional theory (DFT) (B3LYP) with already mentioned basis sets. In addition, Mulliken atomic charges of the atoms are also calculated.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011
2-(4-Fluorophenyl)-1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole (fpmpdi) was synthesised and its structure was characterized by 1 H, 13 C, mass, elemental analysis and X-ray techniques. It belongs to monoclinic crystal system having the lattice dimensions of monoclinic with point group, P 21 /c; a = 8.5132 (1)Å, b = 9.5128 (2)Å, c = 19.2610 (3)Å,ˇ= 96.798 (2). Since (fpmpdi) is highly sensitive to different external stimulations such as UV irradiation, heat, increasing pressure and changing the environmental pH causing color change and so they can be used as a "multi-way" optically switchable material. A prominent fluorescence enhancement was found in the presence of transition metal ions such as Hg 2+ , Pb 2+ and Cu 2+ and this was suggested to result from the suppression of radiationless transitions from the n-* state in the chemosensors. The optimized geometrical parameters obtained by DFT calculation is in good agreement with single crystal XRD data. The Mulliken, NBO charge analysis and the HOMO-LUMO energies were also calculated. The molecular electrostatic potential surface (MEP) and first static hyperpolarisability have also been employed theoretically which reveal that the fpmpdi have non-linear optical (NLO) behavior with non-zero values. Ground and excited states DFT calculations were carried out in order to find out dipole moment and energy.
Indian Journal of Physics, 2019
The molecular geometrical parameters, vibrational frequencies, electronic properties and nonlinear optical (NLO) behavior of 3-amino-4-(Boc-amino)pyridine have been evaluated using the B3LYP, CAM-B3LYP and B3PW91 levels of density functional theory (DFT). The dipole moment (l) and first hyperpolarizability (b) values of the title complex show that the molecule can be a good candidate as NLO material. The energy of HOMO and LUMO levels and the HOMO-LUMO energy gap, hardness, softness and electronegativity have been analyzed using DFT/B3LYP method with the 6-31?G(d,p) basis set. To understand the effect of the different media (gas phase and in methanol solvent) in electronic transitions, the UV-Vis computations of the molecule have been performed using time-dependent DFT (TD-DFT)/6-31?G(d,p) by applying the integral equation formalism-polarized continuum model. The second-order interaction energies of 3-amino-4-(Boc-amino)pyridine have been calculated using natural bond orbital analysis.
Russian Journal of Physical Chemistry A, 2014
In this study, quantum chemical calculations of geometric parameters, conformational, natural bond orbital (NBO) and nonlinear optical (NLO) properties, vibrational frequencies, 1 H and 13 C NMR chemical shifts of the title molecule [C 9 H 7 F 5 N 2 O 3 ] in the ground state have been calculated with the help of Density Functional Theory (DFT-B3LYP/6 311++G(d,p)) and Hartree Fock (HF/6 311++G(d,p)) methods. The optimized geometric parameters, vibrational frequencies, 1 H and 13 C NMR chemical shifts values are compared with experimental values of the investigated molecules. Comparison between experi mental and theoretical results showed that B3LYP/6 311++G(d,p) method is able to provide more satisfac tory results. In order to understand this phenomenon in the context of molecular orbital picture, we examined the molecular frontier orbital energies (HOMO, HOMO 1, LUMO, and LUMO + 1), the energy difference (ΔE) between E HOMO and E LUMO , electronegativity (χ), hardness (η), softness (S) calculated by HF/6 311++G(d,p) and B3LYP/6 311++G(d,p) levels. The molecular surfaces, Mulliken, NBO, and Atomic polar tensor (APT) charges of the investigated molecule have also been calculated by using the same methods.
Indian Journal of Chemistry -Section A
In this paper, the structural, electronic, non-linear optical (NLO) properties and vibrational frequencies of 4-(methoxycarbonyl)-phenylboronic acid have been examined theoretically using ab initio Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) methods applying the standard 6-311++G(d,p) basis set. 1 Hand 13 C NMR chemical shifts are calculated by employing the direct implementation of the gauge including-atomic-orbital (GIAO) method at the B3LYP/6-311++G(d,p) and HF/6-31G(d) levels of the theory. There are two conformers, cis-trans(ct) and trans-cis (tc) for title molecule. The energy difference between ct and tc conformers of studied molecule are of 0.126 kcal/mol with B3LYP/6-311++G(d,p) and 0.138 kcal/mol with HF/6-311++G(d,p), respectively. The conformer ct is more stable than the conformer tc. Also, the energy gap differences between the highest occupied and the lowest unoccupied molecular orbitals, dipole moment, polarizability and first static hyperpolarizability are calculated as a function of both dihedral angle (C3-C4-C7-O3), between methoxycarbonyl group (CH 3-O-CO-) and benzene ring, and dihedral angle (C2-C1-B-O1), between boronic acid group (-B(OH) 2) and benzene ring. In the change of the energy gap and polarizability depending on dihedral angles, it is shown that the polarizabilities follow inverse relationship the energy gaps.
2018
3-Amino Pyrazole (3AP) is used as the remedial agent for the cure of cancer and cell proliferative disorders. In the present communication vibrational frequencies and the structural properties of 3AP have been investigated using Density Functional Theory (DFT) employing B3LYP exchangecorrelation with high level basis set 6-311++G (d, p). The FT-IR Liquid phase (4000-400cm-1) and FT-Raman spectra (4000-400cm-1) of 3AP was recorded at room temperature. By following the Scaled Quantum Mechanical Force Field method (SQMFF) the task of assigning the vibrational spectra by means of Normal Coordinate Analysis (NCA) was obtained and compared with experimental FT-IR and FT-Raman spectra. The NLO properties of 3AP have been computed using quantum mechanical calculations. The Natural Bond Orbital and HOMO, LUMO analysis has also been carried out for the title compound. Thermal properties of 3AP at different temperatures have been calculated on the basis of vibrational analysis. UV-visible spec...
2012
Insensitivity of the error of the minimally empirical hybrid functional revTPSSh to its parameters J. Chem. Phys. 137, 224104 (2012) A first-principles-based correlation functional for harmonious connection of short-range correlation and longrange dispersion J. Chem. Phys. 137, 204121 Determination of Kohn-Sham effective potentials from electron densities using the differential virial theorem J. Chem. Phys. 137, 164113 Harnessing the meta-generalized gradient approximation for time-dependent density functional theory Abstract. The vibrational contributions to the linear and nonlinear optical properties (L&NLO) of some selected systems are reported. The Bishop-Kirtman perturbation approach as well the Numerov-Cooley technique were employed for the computation of the vibrartional properies. Electron correlation and relativistic effects have been considered. The results show that the vibrational contributions are essential for the reasonably accurate description of the L&NLO properties and in particular of the first and second order hyperpolarizabilities.
Physical Chemistry Research, 2018
This work investigates the structural and nonlinear optical properties of a D-A type 1-[4-({(E)-[4-(methylsulfanyl)phenyl]methylidene}amino)phenyl]ethanone, MMP in which charge transfer occurs from -SCH3 donor to -COCH3 acceptor group through methylidene backbone; and some of its modeled analogues using quantum chemical calculations with pure BLYP and hybrid B3LYP correlation with high basis sets, 6-31G* and 6-31G* in gas phase in a bid to understand their structure-property relationship. The molecular properties like the FMOs energies, dipole moments (μ), polarizabilities (α), molecular first hyperpolarizabilities (β) were obtained. The results showed that the molecular properties were enhanced upon substitution with different groups. The β value is a measure of second order susceptibility of molecule; MMP has a β value of 2.44 x10-30 esu (B3LYP), 3.75 times of urea (0.65 x10-30 esu) and 2.61 x10-30(BLYP), 4.02 times that of urea. The experimental SHG efficiency of MMP is 4.13 time...
2018
In this work, we report a theoretical study on molecular structure, electrostatic potential and nonlinear optical properties of Zwitterionic 6-methyl-2-oxo-3-[1-(ureidoiminio)ethyl]-2H-pyran-4-olate monohydrate molecule (monomer and dimer ). The molecular geometry in the ground state was investigated by ab initio and density functional method (B3LYP) with 6-31G(d) and 6-31+G(d,p) basis sets. The results show that the computed geometrical parameters are in good agreement with experimental values. The molecular electrostatic potential and HOMO-LUMO of the title molecule have been also calculated using the theoretical methods. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. In order to investigate the nonlinear optical behavior, the electric dipole moment μ, the polarizability α and the hyperpolarizability β were computed. All β values that we report here are the magnitude of static hyperpolarizability. Theoretically predicted β values exhibi...