Structural and topological analysis of some isobutyl acetophenone azines sprouting out their asymmetrization effect

In this research, three asymmetrical p-isobutyl acetophenone azine 1-3 named 1-(1-(4-isobutylphenyl)ethylidene)-2-(1-phenylethylidene) hydrazine, 1-(1-(4-isobutylphenyl)ethylidene)-2-(1-4-nitrophenylethylidene) hydrazine, 1-(1-(4-isobutylphenyl)ethylidene)-2-(1-4-methoxyphenylethylidene) hydrazine respectively are prepared and characterized by elemental analyses, FT-IR and NMR spectral studies. The stable optimized conformers of the asymmetrical azines (1-3) are predicted using density functional theory (DFT) method. The theoretical IR frequencies are found to be in good agreement with the experimental values. The asymmetrization effect is observed for the three azines 1-3 from their natural population analysis. The comparative analysis of the computed structural properties of the asymmetrical azines (1-3) and symmetrical p-isobutyl acetophenone azine is accomplished. The topological properties of electronic charge density are analyzed employing Atoms In Molecules (AIM) theory. The electron density (ρ) and Laplacian ( ∇ ρ 2 ) properties indicates the presence of two CH⋯N intramolecular bridges in the methoxy substituted asymmetrical azine 3 which paves way for the reduction of electron density in the aromatic systems of the azine 3. Nonlinear optical behavior of the asymmetrical azines is also examined by the theoretically predicted values of dipole moment (μ), polarizability (α0) and first hyperpolarizability (βtot). The α0 and βtot values clearly depicted that the azine 2 is found to have a good non-linear optical (NLO) property than 1 and 3. The azine 2 is found to be NLO active when it had been subjected to experimental second harmonic generation (SHG) test. The UV–Visible methods are also used to characterize the synthesized azines 1-3.