SOLID STATE SYNTHESIS AND CHARACTERIZATION OF PYRAZOLE AND PYRAZOLATES COMPLEXES OF COPPER (II) IONS

Authors

  • T. Abubakar
  • M. A. Kurawa
  • S. Isyaku

Abstract

Two synthetic routes were used to synthesize  copper (II) complexes of pyrazole mechanochemically.The first route involved direct reaction of the appropriate copper (II) acetates with pyrazole and pyrazolium chloride to form bispyrazole copper (II) salts, [(HPz)2CuCl2]. This was further ground in the second route with a two equivalents of a base (KOH) to make polymeric copper (II) pyrazolate [Cu(Pz)2]. In all the syntheses above the ratio of ligand to copper (II) acetate was 2:1. All the copper (II) complexes were found to be of different colour and were characterized by solubility test, which showed that the complexes have poor solubility in most of the solvents used except in dimethylsulfoxide where they were soluble and the complexes studied have low values of molarconductivity  (ranging from 3.46-3.52Ω-1cm2mol-1) which showed that they are non-electrolytes. All the complexes have relatively low decomposition temperatures (80°C- 81°C). Characterization of the complexes via infrared analysis confirmed the coordination of metal with the ligand through pyridine-nitrogen and deprotonated-nitrogen in the range of 459.07cm-1Cu-N 425.32cm-1 Cu-N bonds (for the route A and B respectively). The magnetic susceptibility measurements were carried out at room temperature and the effective magnetic moment values for all the complexes further confirmed complexation of the metal (II) ions with the ligand and also indicates that the copper (II) complexes are paramagnetic (1.74B.M and 1.72 B.M). The plot of absorbance against mole fraction in each case gives a curve with maximum absorbance corresponding to the ligand mole fraction used in calculating the number of coordinated ligands and 1:2 metal-ligand ratios were obtained in all the complexes.Keywords:  Mechanochemical, Pyrazole, Pyrazolate, Pyrazolium Chloride, Grinding, Mechanochemical Elimination, Copper (II) Complex.

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Published

2020-02-09

How to Cite

Abubakar, T., Kurawa, M. A., & Isyaku, S. (2020). SOLID STATE SYNTHESIS AND CHARACTERIZATION OF PYRAZOLE AND PYRAZOLATES COMPLEXES OF COPPER (II) IONS. Journal of Chemical Society of Nigeria, 45(1). Retrieved from http://journals.chemsociety.org.ng/index.php/jcsn/article/view/428