benhalima nadia

In this work, a comprehensive investigation of the salicylideneaniline derivatives is carried out using density functional theory to determine their linear and non-linear optical properties. Geometry optimizations, for gas and solvent phases, of the tautomers (enol and keto forms) are calculated using B3LYP levels with 6-31G (d,p) basis set. An intramolecular proton transfer, for 1SA-E and 2SA-E, is performed by a PES scan process at the B3LYP/6-31G (d,p) level. The optical properties are determined and show that they have extremely high nonlinear optical properties. In addition, the RDG analysis, MEP, and gap energy are calculated. The low energy gap value indicates the possibility of intramolecular charge transfer. The frontier molecular orbital calculations clearly show the inverse relationship of HOMO-LUMO gap with the first-order hyperpolarizability (β = 59.6471 × 10-30 esu), confirming that the salicylideneaniline derivatives can be used as attractive future NLO materials. Therefore, the reactive sites are predicted using MEP and the visible absorption maxima are analyzed using a theoretical UV-Vis spectrum. Natural bond orbitals are used to investigate the stability, charge delocalization, and intramolecular hydrogen bond. 1. Introduction Salicylideneaniline derivatives are of great interest due to the formation of O-H…N (phenolimine) and O…H-N (keto-amine) type hydrogen bonds, which result in tautomerization

Density functional theory (DFT) calculations were performed in the ground state of 2-phenylbenzofuran using the GGA-PBE, PBV86, and meta-GGA TPSS hybrid functionals with the 6-31G(d,p) basis set. First, theoretical calculations were performed using the above functionals to obtain the stable conformer of the molecule. In addition, Mulliken population, natural population, and natural bond orbital analyses were carried out. The molecular electrostatic potential, band gap energies, global and local reactivity descriptors, and nonlinear optical (NLO) properties were studied. Additionally, the NLO properties of 2-phenylbenzofuran and those of its derivatives were investigated by the GGA-PBE/6-31G(d,p) level of theory. The first-order hyperpolarizability of all 2-phenylbenzofuran derivatives was found to be varying from 4.00 × 10-30 to 43.57 × 10-30 (esu), indicating that they possess remarkable NLO properties. In addition, a multiple linear regression model was used to model the relationships between molecular descriptors and the activity of 2-phenylbenzofuran derivatives. Quantitative structure-activity relationship (QSAR) studies were performed using quantum chemical descriptors. The QSAR was applied to determine the relationship between various physico-chemical parameters of the studied compounds and their biological activities. The statistical quality of the QSAR models was assessed using statistical parameters, i.e., R 2 , R 2 adj , and R 2 cv .

We report here the synthesis of (Z)-5-(4-nitrobenzyliden)-3-N(2-ethoxyphenyl)-2-thioxo-thiazolidin-4-one (ARNO) compound. The crystal structure has been determined by X-ray diffraction. The compound crystallizes in the triclinic system with space group P " 1 and cell parameters: a = 9.1289(19), b = 9.3717(7), c = 12.136(3) Å , a = 102.133 (11)°, b = 90.99(2)°, c = 117.165(9)°, V = 895.4(3) Å 3 and Z = 2. The structure has been refined to a final R = 0.05 for 2591 observed reflections. The refined structure was found to be significantly non planar. The molecule exhibits intermolecular hydrogen bond of type C-H_O and C-H_S. ab initio calculations were also were performed at Hartree-Fock and density functional theory levels. The full HF and DFT geometry optimization was carried out using LANL2DZ, 6-31G* and B3LYP/6-31?G** basis sets. The optimized geometry of the title compound was found to be consistent structure determined by X-ray diffraction. The minimum energy of geometrical structure is obtained by using level HF/LANL2DZ basis sets.

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 ...

Density functional theory (DFT) calculations have been performed to obtain optimized geometries, vibrational wavenumbers, highest occupied molecular orbital (HOMO)lowest unoccupied molecular orbital (LUMO) energies, nonlinear optical (NLO), and thermodynamic properties as well as molecular surfaces for N-(2,3-dichlorophenyl)-2-nitrobenzene-sulfonamide in different solvents. B3LYP level gives similar results for geometric parameters and vibration frequencies in gas phase, water, and ethanol solvents. The most stable structure, which is defined by the highest energy gap between H O M O a n d L U M O , i s o b t a i n e d i n g a s p h a s e (ΔE = 10.7376 eV). Obtained small energy gaps between HOMO and LUMO demonstrate the high-charge mobility in the titled compound. The magnitude of first static hyperpolarizability (β) parameter increases by the decreasing HOMO-LUMO energy gap. The intensive interactions between bonding and antibonding orbitals of titled compound are responsible for movement of π-electron cloud from donor to acceptor, i.e., intramolecular charge transfer (ICT), inducing the nonlinear optical properties. So, the β parameter for title compound is found to be in the range of 5.5255-3.7187 × 10 −30 esu, indicating the considerable NLO character. All of these calculations have been performed in gas phase as well as water and ethanol solvents in order to demonstrate solvent effect on molecular structure, vibration frequencies, NLO properties, etc.