Synthesis and characterization of copper(II), nickel(II), cobalt(II) and zinc(II) complexes of 3-(1-hydroxy-2-naphthyl)-5-(4-x-phenyl)pyrazolines

Abstract

Metal complexes of the type ML₂nB, [M= Cu(II), Ni(II), Co(II), Zn(I1); L= 3-(I-hydroxy-2-naphthyl)-5-(4-X-phenyl) pyrazoline (HONXPP); X = H, Me, MeO; B = H₂O, Py; n=0, 2] have been synthesized through different routes and characterized on the basis of analysis, infrared, ligand field and ¹H NMR spectra and magnetic susceptibility measurements. IR and ¹H NMR data indicate that the ligands act as bidentate, coordinating through the oxygen of phenolic group and tertiary nitrogen of pyrazoline ring. All the copper(II) and nickel(II) complexes are obtained in the anhydrous from with square-planer configuration whereas cobalt(II) and nicke(II) complexes are isolated as diaquates and dipyridinates with high-spin octahedral geometry. The corresponding anhydrous nickel(II) complexes are diamagnetic with square-planer structure, whereas and anhydrous cobalt(II) complexes are polymeric with cobalt in an octahedral environment. Enhanced π-bonding between nickel and C = N in the square complexes increases the LFSE.