Characterization of some arylhydrazone-5-pyrazolones and their chelates with divalent Fe, Co, Ni, Cu, and Zn ions

ABSTRACT

The pK values of two substituted arylhydrazo-5-pyrazolones are assigned to the dissociation of a proton from the corresponding functional groups. The stability constants of their chelates with some divalent metal ions, viz. Fe [II], Co [II], Ni [II], Cu [II] and Zn [II] have also been determined. The structure of the compounds prepared has been elucidated by IR and NMR spectra which indicate the quinone-hydrazone form rather than the hydroxy-azo or Zwitter ion structures. Solid chelates were isolated and characterized