SYNTHESES AND CHARACTERIZATION OF 4-ISO-BUTYRYL AND 4-ISO-VALEROYL DERIVATIVES OF 1-PHENYL-3-METHYL-PYRAZOLONE-5 AND THEIR URANIUM(VI), THORIUM(IV), LANTHANUM(III), IRON(III), LEAD(II) AND CALCIUM(II) COMPLEXES

4-iso-Butyryl and 4-iso-valeroyl derivatives of 1-phenyl-3-methyl-pyrazolones and some of their U(VI), Th(IV), La(III), Fe(III), Pb(II) and Ca(II) complexes have been synthesised. The compounds were characterized by elemental, UV-visible, IR (4000 - 200) cm-1, H-1 and C-13 NMR spectral analyses. The 4-iso-acyl-pyrazolones behave as bidentate keto-enol tautomers, forming neutral metal complexes which conform to a general molecular formula MLn.xH2O, where L is the 4-iso-acyl-pyrazolone anion and m(n)(x) is UO2(2)(2). Th(4)(0), La(3)(0), Fe(3)(0), Pb(2)(0) or Ca(2)(1/2). Spectral analyses revealed that apart from CO-U bond the other CO-M bonds are weak.