Synthesis, Magnetic, and Spectral Studies of Mixed‐Ligand Complexes of Nickel(II) Involving Some Chelating 4‐Oximino‐2‐pyrazoline‐5‐one Derivatives

Abstract

The synthesis, magnetic and spectral studies of mixed‐ligand complexes of nickel(II) derived from chelating 4‐oximino‐2‐pyrazoline‐5‐one derivatives, viz., 4‐benzoyloxime‐3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one (bomppH), 4‐acetyloxime‐3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one (aomppH) and 3‐methyl‐1‐phenyl‐4‐propionyloxime‐2‐pyrazoline‐5‐one (mppopH), and certain heterocyclic ligands, viz., 3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one (mpp), 4‐amino‐2,3‐dimethyl‐1‐phenyl‐3‐pyrazoline‐5‐one (adpp), 2,3‐dimethyl‐1‐phenyl‐3‐pyrazoline‐5‐one (dpp), 2,3‐dimethyl‐4‐methylaminomethanesulfonate sodium‐1‐phenyl‐3‐pyrazoline‐5‐one (dmspp), benzimidazole (bzl) and benzothiazole (bzt) are described. The complexes, which have been characterized by conductance measurements, electron spin resonance, magnetic measurements, thermogravimetric analyses, electronic and infrared spectral studies have the general formulas [Ni(A–A)₂(L)₂] and [Ni(A–A)₂(L–L)] where, (A–A)H = bomppH, aomppH, or mppopH, L = mpp, dpp, bzl or bzt and L–L = adpp or dmspp. All the complexes were found to be non‐electrolytes and octahedral structures have been proposed for them.

Keywords:

• Mixed‐ligand Ni(II) chelates
• Spin free octahedral symmetry
• 4‐Oximino‐2‐pyrazoline‐5‐one derivatives
• Nuclear hyperfine coupling
• trans‐Octahedral structure
• cis‐Octahedral structure

Acknowledgments

We are thankful to Professor S. D. Tripathi, Vice‐chancellor of this University, for encouragement, and Professor K. K. Mishra, Head, Department of Chemistry, for laboratory facilities and helpful discussion. Analytical facilities provided by the Central Drug Research Institute, Lucknow, India, and the Regional Sophisticated Instrumentation Centre, Indian Institute of Technology, Chennai, India, are gratefully acknowledged.