Abstract

The thermal dissociation of 1-phenyl-3-methyl-4-(X-phenylhydrazo)-5-pyrazolone metal ch-lates [M(XPhHyPy)](X = m-OH (I), m-OCH3 (II), m-COOH (III), p-CH3 (IV), p-OCH3 (V) or p-COCH3 (VI) was studied by TG, I7IY3 and differential thermal analysis (DTA). A rough se-quence of thermal stability, obtained from the peak maximum temperatures, for the various metal chelates was Hg(lI) < Cu(II) < Fe(llI) < UO2(II). The bonding of the ligands to metal ions was investigated by elemental analysis and infrared spectroscopy. The number and relative energies of nitrate combination frequencies are discussed in terms of the complexation ofpara-substituted hydrazopyrazolone with Th(IV) and UO2(II) metal ions.