THE COORDINATION CHEMISTRY OF DIOXOURANIUM(VI) - STUDIES ON SOME NOVEL DINUCLEAR AND TRINUCLEAR DIOXOURANIUM(VI) COMPLEXES WITH PYRAZOLONE BASED SCHIFF-BASES

A new series of eight complexes of dioxouranium(VI) with some Schiff b ases derived from methyl-4-p-nitrobenzoyl-1-phenyl-2-pyrazolin-5-one a nd certain aromatic amines, viz., p-anisidine (MNBHP-PAH), m-phenetidi ne (MNBPHP-MPH), o-toluidine (MNBPHP-OTH), ethylenediamine (MNBPHP-END H2), g-phenylenediamine (MNBPHP-OPHDH2), m-phenylenediamine (MNBPHP-MP HDH2), p-phenylenediamine (MNBPHP-PPHDH2) or benzidine (MNBPHP-BZH(2)) have been synthesized. These complexes have been characterized by ele mental analyses, molar conductances, magnetic measurements, electronic and infrared spectral studies, and are formulated as [(UO2)(2)( mu-OH )(2)(L)(2)(H2O)(2)] (1), (2) and (3) (where LH = MNBPHP-PAH, MNBPHP-MP H or MNBPHP-OTH), [(UO2)(3)(mu-OH)(4)(mu-MNBPHP-END)] (4), [(UO2)(2)( mu-L)( mu-OH)(2)] (5) and (6) (where LH2 = MNBPHP-OPHDH2 or MNBPHP-MPH DH2) and [(UO2)(2)(H2O)(2) = ( mu-L)(OH)(2)] (7) and (8) (where LH2 =M NBPHP-PPHDH2 or MNBPHP-BZH(2)). Di- and trinuclear structures have bee n proposed for these complexes where complexes (1)-(3) appear to conta in hydroxo bridges, complexes (4)-(6) hydroxo and ligand bridges, and complexes (7) and (8) ligand bridges.