THERMAL-DECOMPOSITION OF SOME METAL-CHELATES OF SUBSTITUTED HYDRAZOPYRAZOLONES

The thermal dissociation of 1-phenyl-3-methyl-4-(X-phenylhydrazo)-5-py razolone metal chelates [M(XPhHyPy)] (X = m-OH (I), m-OCH3 (II), m-COO H (III), p-CH3 (IV), p-OCH3 (V) or p-COCH3 (VI) was studied by TG, DTG and differential thermal analysis (DTA). A rough sequence of thermal stability, obtained from the peak maximum temperatures, for the variou s metal chelates was Hg(II) < Cu(II) < Fe(III) < UO2(II). The bonding of the ligands to metal ions was investigated by elemental analysis an d infrared spectroscopy. The number and relative energies of nitrate c ombination frequencies are discussed in terms of the complexation of p ara-substituted hydrazopyrazolone with Th(IV) and UO2(II) metal ions.