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The molecular geometry and vibrational frequencies of 1-[N-(2-pyridyl)aminomethylidene}-2(1H)-Naphtalenone in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-311++G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The computed vibrational frequencies were used to determine the types of molecular motions associated with each of the experimental bands observed. In addition, calculated results are related to the linear correlation plot of computed data versus experimental geometric parameters and IR data. From the results it was concluded that the B3LYP method is superior to the HF method for the vibrational frequencies. Using the time-dependent density functional theory (TD-DFT) and Hartree-Fock (TD-HF) methods, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and experimental ones is determined., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In the present work, a combined experimental and theoretical study on ground state molecular structure, spectroscopic and nonlinear optical properties of azo compound 3'-chloro-4-dimethlamino azobenzene are reported. The molecular geometry, vibrational wavenumbers and the first order hyperpolarizability of the title compound were calculated with the help of density functional theory computations. The optimized geometric parameters obtained by using DFT (B3LYP/6-311++G(d,p)) show good agreement with the experimental data. The vibrational transitions were identified based on the recorded FT-IR spectra in the range of 4000-400cm(-1) for solid state. The (1)H isotropic chemical shifts with respect to TMS were also calculated using the gauge independent atomic orbital (GIAO) method and compared with the experimental data. Using the TD-DFT method, electronic absorption spectra of the title compound have been predicted, and good agreement is determined with the experimental ones. To investigate the NLO properties of the title compound, the polarizability and the first hyperpolarizability were calculated using the density functional B3LYP method with the 6-311++G(d,p) basis set. According to results, the title compound exhibits non-zero first hyperpolarizability value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential and frontier molecular orbitals were also performed at 6-311++G(d,p) level of theory., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The Schiff base compound (E)-N'-((5-nitrothiophen-2-yl)methylene)-2-phenoxyaniline has been synthesized and characterized by IR, UV-Vis, and X-ray diffraction (XRD) methods. The molecular geometry from X-ray experiment in the ground state has been compared using the density functional theory (DFT) with the 6-311++G(d,p) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequency values show good agreement with experimental values. By using TD-DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental one is determined. The energetic behavior of the title compound in solvent media has been examined using B3LYP method with the 6-311++G(d,p) basis set by applying the Onsager and the integral equation formalism polarizable continuum model (IEF-PCM). The predicted nonlinear optical properties of the title compound are greater than ones of urea. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), natural bond orbital (NBO) and thermodynamic properties were performed at B3LYP/6-311++G(d,p) level of theory., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The molecular geometry and vibrational frequencies of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II) in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-311G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The energetic and atomic charge behavior of the title compound in solvent media has been examined by applying the Onsager and the polarizable continuum model. To investigate second order nonlinear optical properties of the title compound, the electric dipole (μ), linear polarizability (α) and first-order hyperpolarizability (β) were computed using the density functional B3LYP and CAM-B3LYP methods with the 6-31+G(d) basis set. According to our calculations, the title compound exhibits nonzero (β) value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), frontier molecular orbitals, and thermodynamic properties were performed at B3LYP/6-311G(d,p) level of theory., (Copyright © 2013 Elsevier B.V. All rights reserved.)

4-(4-Methoxyphenethyl)-3,5-dimethyl-4H-1,2,4-triazole (3) was synthesized from the reaction of ethyl N'-acetylacetohydrazonate (1) with 2-(4-methoxyphenyl)ethanamine (2). The structure of the title compound 3 has been inferred through IR, (1)H/(13)C NMR, mass spectrometry, elemental analyses and combination of X-ray crystallography and theoretical methods. In addition to the molecular geometry from X-ray determination, the molecular geometry and vibrational frequencies of the title compound 3 in the ground state, were calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure and the theoretical vibrational frequencies show good agreement with experimental values. The nonlinear optical properties are also addressed theoretically. The predicted nonlinear optical properties of 3 are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials and frontier molecular orbitals of the title compound were carried out at the B3LYP/6-31G(d) level of theory., (Copyright © 2012. Published by Elsevier B.V.)

The experimental and theoretical vibrational spectra of Bis(melaminium) terephthalate dihydrate were studied. The Fourier transform infrared (FT-IR) spectra of the Bis(melaminium) terephthalate dihydrate and its deuterated analogue were recorded in the solid phase. The molecular geometry and vibrational frequencies of Bis(melaminium) terephthalate dihydrate in the ground state have been calculated by using the density functional method (B3LYP) with 6-31++G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The molecule contains the weak hydrogen bonds of N-H···O, N-H···N and O-H···O types, and those bonds are calculated with DFT method. In addition, molecular electrostatic potential, frontier molecular orbitals and natural bond orbital analysis of the title compound were investigated by theoretical calculations. The lack of the second harmonic generation (SHG) confirms the presence of macroscopic center of inversion., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The triazol compound 4-(4-methoxyphenethyl)-5-benzyl-2H-1,2,4-triazol-3(4H)-one monohydrate (I) has been synthesized and characterized by (1)H NMR, (13)C NMR, IR, and X-ray single-crystal determination. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of (I) in the ground state have been calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies and chemical shift values show good agreement with experimental values. The energetic behavior of (I) in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The predicted non-linear optical properties of (I) are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials, frontier molecular orbitals and thermodynamic properties of (I) were carried out at the B3LYP/6-31G(d) level of theory., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The Schiff base compound (E)-2-[(2-Bromophenyl)iminomethyl]-4-trifluoromethoxyphenol has been synthesised and characterised by IR, UV-vis, and X-ray single-crystal determination. The molecular geometry from X-ray determination of the title compound in the ground state has been compared using the Hartree-Fock (HF) and density functional theory (DFT) with the 6-311++G(d,p) basis set. The calculated results show that the DFT and HF can well reproduce the structure of the title compound. Using the TD-DFT and TD-HF methods, electronic absorption spectra of the title compound have been predicted and good agreement with the TD-DFT method and the experimental determination was found. The predicted nonlinear optical properties of the title compound are much greater than those of urea. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), natural bond orbital (NBO), and thermodynamic properties were performed at B3LYP/6-311++G(d,p) level of theory., (Copyright © 2011 Elsevier B.V. All rights reserved.)