A Combined Experimental (XRD, FT-IR, and UV-Vis) and DFT Computational Studies on (E)-N Methanimine

Abstract

(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. © 2015 Taylor & Francis.