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The synthesis and crystal structure of benzyl 4-([1,1'-biphenyl]-4-yl)-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate are described. Single crystal X-ray diffraction of title molecule was used to investigate the crystal structure. The most stable optimised structure was identified using the B3LYP/6-31 + G(d) method. IR, 1H-NMR and elemental analysis of the title compound were performed. Besides, frontier molecular orbitals, molecular electrostatic potential, and thermodynamic properties were investigated by theoretically. In order to explore the nonlinear optical properties were performed theoretically. Hirshfeld analysis was also performed to determine the interactions of the molecule. [ABSTRACT FROM AUTHOR]

(E)-N-[4-bromo-2-(trifluromethoxy)phenyl]-1-(5-nitrothiophen-2-yl)methanimine, an organic Schiff base compound has been synthesised and characterised by FT-IR, UV-Vis, and X-ray single-crystal determination. The molecular geometry from X-ray experiment in the ground state has been compared using the density functional theory (DFT)/B3LYP with the 6−311++G(d,p) basis set. The calculated results show that the DFT can well reproduce the crystal structure, and the calculated frequencies show good agreement with experimental values. The TD-DFT calculations were carried out using the B3LYP and CAM-B3LYP functionals with the 6−311++G(d,p) basis set to determine the maximum absorbtion wavelength of the UV-Vis spectra for the title compound. In addition, solvent effects on the excitation energies were computed through the integral equation formalism of the polarisable continuum model (IEF-PCM). The energetic and chemical reactivity behaviours of the title compound in solvent media have been examined using the B3LYP method with the 6−311++G(d,p) basis set by applying the IEF-PCM model. The non-linear optical properties are also addressed theoretically. According to the results, the title compound shows non-zero, the first hyperpolarisability value revealing second-order non-linear optic behaviour. Besides, DFT calculations of the molecular electrostatic potential, natural bond orbital analysis, and thermodynamic properties were also performed at B3LYP/6−311++G(d,p) level of theory. [ABSTRACT FROM PUBLISHER]

Density functional calculations of the structure, vibrational spectra, molecular electrostatic potential and thermodynamic functions have been performed at the B3LYP/6-311++G(d,p) level of theory for the Schiff base compound 2-[(2,4-Dimethylphenyl)iminomethyl]-6-methylphenol. Experimental and theoretical Fourier transform infrared (FT-IR) studies of the title compound show the preference of enol form, as supported by X-ray analysis results. Using the time-dependent density functional theory (TD-DFT) method, electronic absorption spectra of the compound have been predicted and a good agreement is determined with the experimental ones. To investigate the tautomeric stability, optimisation calculations at B3LYP/6-311++G(d,p) level were performed for the enol and keto forms of the title compound. Calculated results show that its enol form is more stable than that of the keto form. The predicted non-linear optical properties of the title compound are much greater than those of urea. The changes in thermodynamic properties for the formation of the title compound with the temperature ranging from 200 K to 500 K have been obtained using the statistical thermodynamic method. At 298.15 K the change of Gibbs free energy for the formation reaction of the title compound is 37.03 kJ/mol. The title compound cannot be spontaneously produced from the isolated monomers at room temperature. The tautomeric equilibrium constant is also computed as 1.23×10−3at 298.15 K for enol ↔ keto tautomerisation of the title compound. [ABSTRACT FROM AUTHOR]