Equimolar and bimolar reactions of zirconium isopropoxide with bibasic tridentate azomethine (AZH₂) having the donor system ONO have been carried out and derivatives of the type Zr(OPr¹)₂(AZ) and Zr(AZ)₂ [Where AZ²⁻ is the anion of the azomethine molecule] have been isolated. The labile nature of the isopropoxy groups in 1∶1 derivatives has been shown by carrying out exchange reactions with equimolar amount of 2-methylpentane-2,4-diol. All the newly synthesized derivatives have been characterized on the basis of elemental analysis, conductance measurements, molecular weight determinations and infrared, ultraviolet, visible and proton magnetic resonance spectral studies.

Equilibria between the derivatives ofo-hydroxy naphthaldehyde and protons or bivalent metal ions have been investigated potentiometrically at constant ionic strength while varying the solvents in definite ratios (solvent: water). The method of Bjerrum and Calvin as modified by Irving and Rossotti (1954) has been used to find the values of$$\tilde n$$ and pL. The formation constants of metal chelates have been calculated using a weighted least squares method. The values of$$S_{\min } = \chi ^2 $$ have also been calculated. The order of stability constants is determined as Mg²⁺<Mn²⁺<Cd²⁺<Pb²⁺<Zn²⁺<Co²⁺<Ni²⁺<Cu²⁺<UO₂²⁺ Solvent effects on stability constants and comparative studies of both the derivatives ofo-hydroxy naphthaldehyde have been reported.