Synthesis and Characterization of Some Oximino Metal Complexes Using Magnetic and Spectral Data Predicting Anticipated Geometry

Abstract

This study presents the synthesis and characterization of four organic ligands: malon-di-anilide oxime (HINMAO), malon-di-(p-toluidide) oxime (HINM-p-TO), malon-di-(o-anisidide) oxime (HINM-o-ANISO), and malon-di-(p-anisidide) oxime (HINM-p-ANISO). Their molecular formulas were confirmed through elemental analysis, infrared (IR), and electronic spectral studies. These ligands were used to prepare solid-state metal complexes with Cu (II) acetate, Cu (II) nitrate, UO₂(II) nitrate, Mn (II) chloride, and Pb (II) acetate, which were further characterized for their structural and magnetic properties. The Cu (II) complexes exhibited subnormal magnetic moments following the Bleaney-Bowers equation, with ESR spectra (g = 2.015 – 2.150) confirming square planar geometry and oxygen-bridged dimeric structures. The UO₂(II) complexes displayed low magnetic moments due to ligand field effects and adopted pentagonal bipyramidal geometry, as confirmed by electronic and infrared spectral analysis. The Mn (II) complexes exhibited magnetic moments of 5.8–5.9 BM, indicative of tetrahedral coordination. The Pb (II) complexes were found to be diamagnetic, showing a single electronic absorption band at ~400 nm, suggesting a tetrahedral structure. All synthesized metal complexes were insoluble in water and most organic solvents, suggesting their polymeric nature. These findings provide valuable insights into the coordination chemistry of these novel ligands and their potential applications in materials science and catalysis.