Synthesis and magnetic properties of poly(p-phthaloyl-disacetylaceton-ethylenediimine) metal complexes

Macrocyclic Schiff-base ligand, bisacetylaceton-ethylene-diimine (BAE) and its transition metal complexes M(BAE) (M = Cu²⁺, Ni²⁺) were synthesized. The complexes having characteristics of aromatic systems and well-defined one-dimensional structures, reacted with p-phthaloyl chloride, to obtain polymer complexes. The complexes were characterized by elemental analysis, inductively coupled plasma (ICP), FT-IR, and thermal analysis and show good thermal stability. ESR spectra analysis discovered that there are free radicals in the chain of polymers, indicating that a weak magnetic spin-exchange interaction operates between the metal ions and free radicals. It is found that, as the bridging p-phthaloyl group is able to propagate the magnetic exchange interaction, the polymer complexes show paramagnetic properties by measurement of temperature dependence of the magnetic property, and obey Curie-Weiss law.