Synthesis, characterization and equilibrium studies of copper(ll), nickel(II), manganese(II), zinc(II), cobalt(II) and chromium(lll) complexes of 5-cyano-1,6-dihydro-4-methyl-1-<i>p</i>-tolyl-6-oxopyridazine- 3-carboxylic acid hydrazide

Abstract

The formation constants of a series of complexes of 5-cyano-1, 6-dihydro-4-methyl-1-<i>p</i>-tolyl-6-oxopyridazine-3-carboxylic acid hydrazide (II) with some bivalent metal ions viz. Cu(ll), Ni(ll), Mn(II), Zn(ll) and Co(lI) have been determined potentiometrically in 70% aq. ethanol. The compIexes of Cr(III), Co(II), Mn(II), Cu(ll) and Ni(ll) have also been isolated and characterised by elemental analysis, thermogravimetry, IR, NMR, electronic spectra, conductance and magnetic measurements. The ligand forms complexes of the type [MLCI] with Cu(ll) and Mn(lI) and of the type [ML₂ ]^.nH₂O (where n = 1, 2 and 4) with Co(ll), Ni(lI) and Cr(lll) respectively. L is found to be a uninegatively charged tridentate ligand. The ligand field parameters of the octahedral complexes have been calculated.