Synthesis and structural characterization of Ni(II) complexes containing a heterocyclic NO donor ligand

• Published in: Polyhedron 2011-11, Vol.30 (17), p.2849-2855
• Main Authors: Vimal Kumar, P.M., Radhakrishnan, P.K.
• Format: Article
• Language: English
• Subjects: Crystal structure; Magnetism; Ni(II) complexes; Schiff base; Spectra
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2011.08.013

The present investigation reports the synthesis of a series of nickel(II) complexes [Ni(Opdac) 2]Cl 2 ( 1), [Ni(Opdac) 2(CH 3OH) 2]Br 2(CH 3OH) 2 ( 2), [Ni(Opdac) 2]I 2 ( 3), [Ni(Opdac) 2NO 3]NO 3 ( 4) and [Ni(Opdac) 2ClO 4]ClO 4 ( 5) with the Schiff base ligand, 4-(1-H-1,3-benzimidazole-2-yl)-1,5-dimethyl-2-phenyl-1-2-dihydro-3-H-pyrazol-3-one (Opdac) and their characterization. In all the complexes, Opdac acts as neutral bidentate ligand forming six membered chelate ring around the central metal ion. [Display omitted] ► Ni(II) complexes of heterocyclic NO donor ligand. ► Synthesis, characterization and crystal structure. ► The complex 2 crystallizes in the monoclinic P2 1/ c space group. Five novel nickel(II) complexes have been successfully synthesized with a heterocyclic ligand, Opdac, [Ni(Opdac) 2]Cl 2 ( 1), [Ni(Opdac) 2(CH 3OH) 2]Br 2(CH 3OH) 2 ( 2), [Ni(Opdac) 2]I 2 ( 3), [Ni(Opdac) 2NO 3]NO 3 ( 4) and [Ni(Opdac) 2ClO 4]ClO 4 ( 5) where Opdac = 4-(1-H-1,3-benzimidazole-2-yl)-1,5-dimethyl-2-phenyl-1-2-dihydro-3-H-pyrazol-3-one. All the complexes were characterized by elemental analysis, molar conductivity, CHN analysis, magnetic susceptibility measurements, spectroscopic studies and TG/DTA methods. In all the complexes, Opdac acts as a bidentate ligand coordinating to Ni(II) ion via the benzimidazole imine nitrogen and the pyrazolone oxygen atoms. The complexes 1 and 3 have a tetrahedral geometry while 2, 4 and 5 have an octahedral geometry around the Ni(II) center.