Synthesis and crystal structure of hydroxyacetophenone Schiff bases containing propargyl moiety: Solvent effects on UV–visible spectra

Four tetradentate (N2O2) and tridentate (NO2) Schiff base compounds (L1–L4) with propargyl moiety were prepared by the condensation of 1-[2-hydroxy-4-(prop-2-yn-1-yloxy)phenyl]ethanone with various aliphatic amines. The newly synthesized compounds (L1–L4) were characterized on the basis of the results of elemental analysis, thermal analysis, FT-IR, 1H NMR spectroscopic studies and single crystal X-ray crystallography. The different bands observed in the electronic spectra of the compounds in various organic solvents have been assigned to the proper electronic transitions. The hydrogen bonding and tautomeric equilibria in both of solution and the solid state are explained. The solvatochromism of the synthesized compounds in different solvents in the UV–visible spectra are discussed.

Four novel tetradentate (N2O2) and tridentate (NO2) Schiff bases containing propargyl moiety have been synthesized. The structure of the synthesized Schiff bases is characterised by spectroscopic (IR, 1H NMR and UV–visible), and single crystal X-ray method. A detailed assignment of the spectra and the solvatochromic behaviour of the Schiff bases are discussed.Figure optionsDownload as PowerPoint slideHighlights
► Schiff bases containing propargyl moiety (L1–L4) are synthesised.
► Characterized by IR, 1H NMR, UV–visible spectroscopy & X-ray crystallography.
► Hydrogen bonding and tautomeric equilibria in solution and solid state are explained.
► Solvatochromism of the Schiff bases in different solvents are investigated.