Synthesis and Spectroscopic Studies of a Novel Schiff Base Derived from o‐Acetoacetylphenol and Ethylamine and Its Metal Complexes

Abstract

A Schiff base ligand, H2L, was prepared by the condensation of o‐acetoacetylphenol with ethylamine in the molar ratio 1:1. The Schiff base acts either as monobasic or dibasic ligand and contains O,O,N coordination sites. It reacts with the cations Cu(II), Ni(II), Co(II), Mn(II), VO(IV), UO2(VI), Fe(III) and Cr(III) to yield either mono‐ or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, ESR and UV‐Visible spectra. Also, the magnetic moments and electrical conductances of the complexes were determined. The Cu(II), Ni(II), VO(IV) and UO2(VI) complexes are mononuclear, the first two being coordinated to N,N,O,O sites of two ligand molecules, while the latter to O,O,O,O sites. The Cu(II) complex has a square‐planar geometry distorted towards tetrahedral, the Ni(II) complex is octahedral while the VO(IV) and UO2(VI) complexes have their favored penta‐and hepta‐coordinations, respectively. The Co(II), Mn(II) complexes and also another Ni(II) complex, which was obtained in the presence of LiOH as a deprotonating agent, are binuclear and coordinated via the N,N,O,O and O,O,O,O sites of two ligand molecules. The Fe(III) and Cr(III) complexes consist of two mononuclear units, where the cation in each unit is coordinated to O,O,N sites of a ligand molecule, and are linked together by chlorine atoms or two hydroxyl groups, respectively. All the binuclear complexes have octahedral geometries.