4-BENZOYL-3-METHYL-1-PHENYLPYRAZOL-5-ONE BASED COMPLEXES OF NICKEL(II) AND COBALT(III) WITH A SCHIFF BASE

Coordination compounds of cobalt and nickel with an azomethine ligand (a product of 4-benzoyl-3-methyl-1-phenylpyrazol-5-one and 2-aminophenol condensation) are prepared and studied by XRD. It is established that Co(II) ions under the reaction conditions are oxidized to Co(III) to form (Et3NH)[CoL2]center dot 2H(2)O complexes, whereas Ni(II) ions form the (Et3NH)(H3L)[NiL(HL)]center dot H2O center dot Solv compound. The anionic part of the nickel complex is a supramolecular dimer [Ni(L)(HL)](2)(2-) assembled due to hydrogen bonds. The complexes are studied by static magnetic susceptibility techniques. It is shown that the Co compound is diamagnetic; this is confirmed by the oxidation of this compound and indicates that the metal ion occurs in the low-spin state. Weak ferromagnetic interactions of Ni(II) ions through bridging hydrogen bonds are discovered.