Theoretical and Experimental Electrostatic Potential around the m-Nitrophenol Molecule

This work concerns a comparison of experimental and theoretical results of the electron charge density distribution and the electrostatic potential around the m-nitrophenol molecule (m-NPH) known for its interesting physical characteristics. The molecular experimental results have been obtained from a high-resolution X-ray diffraction study. Theoretical investigations were performed using the Density Functional Theory at B3LYP level of theory at 6-31G* in the Gaussian program. The multipolar model of Hansen and Coppens was used for the experimental electron charge density distribution around the molecule, while we used the DFT methods for the theoretical calculations. The electron charge density obtained in both methods allowed us to find out different molecular properties such us the electrostatic potential and the dipole moment, which were finally subject to a comparison leading to a good match obtained between both methods. The intramolecular charge transfer has also been confirmed by an HOMO-LUMO analysis

Solvent Effects on Molecular Structure, Vibrational Frequencies, and NLO Properties of N-(2,3-Dichlorophenyl)-2-Nitrobenzene-Sulfonamide: a Density Functional Theory Study

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 HOMO and LUMO, is obtained in gas phase (a dagger E = 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 (beta) 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 pi-electron cloud from donor to acceptor, i.e., intramolecular charge transfer (ICT), inducing the nonlinear optical properties. So, the beta parameter for title compound is found to be in the range of 5.5255-3.7187 x 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

Investigation of NLO properties and molecular docking of 3,5-dinitrobenzoic acid with some benzamide derivatives

International audienceThe linear and nonlinear optical (NLO) properties of 3,5-dinitrobenzoic acid and some benzamide derivatives are determined using density functional theory. The B3LYP levels with a 6−311+G(d,p) basis are used to geometrically optimize 3,5-dinitrobenzoic acid with benzamide derivatives (DBBZM, DB1BZM, DB2BZM, DB3BZM, and DB4BZM). The low energy gap value indicates the possibility of intramolecular charge transfer. These calculations clearly show that the studied molecules can be used as attractive future NLO materials. Their first-order hyperpolarizability is found to be in the [3.479×10−30, 12.843×10−30 esu] range, indicating that they have significant NLO properties. Furthermore, the RDG, AIM, NBO analyses, the MEP, and gap energy are calculated. The presence of intermoleculars O–H⋯O and N–H⋯O is confirmed by a topological feature at the bond critical point, determined by AIM theory and NBO analyses. All of these calculations have been performed in gas phase as well as cyclohexane, toluene, and water solvents in order to demonstrate solvent effect on molecular structure and NLO properties. In a final step, a molecular docking study was performed to understand the structure–activity relationship