DIOXOURANIUM(VI) AND THORIUM(IV) COMPLEXES OF 1-METHYL-2,2'-BISIMIDAZOLE

The biheterocyclic nitrogen donor ligand 1-methyl-2,2'-bisimidazole (M BIM) reacts with UO(2)X(2) and ThX(4) to form mononuclear complexes of the types UO2 (MBIM)X(2) (X = Cl, I, NCS, NO3, CH3COO, 0.5 SO4) and T h(MBIM)(2)X(4) (X = NO3, I). The complexes are characterised by elemen tal analyses, conductivity, thermogravimetry and IR, NMR as well as ma ss spectra The IR spectra of uranyl complexes exhibit nu(U = 0) in the regions 900-925 and 825-860 cm(-1) in addition to the vibrational ban ds of the ligand and those of the polyatomic anions. The H-1 NMR spect ra of the ligand and the complexes are identical, with the -CH3 group resonating at 3.5 ppm and the NH proton at 3.9 ppm region. The ring pr otons are observed as multiplets in the region of 7.0 to 8.0 ppm. The mass spectra of the ligand gives molecular ion peak at m/z 148 and oth er fragmentation products, which are appropriately assigned. However, for the complexes neither the molecular ion peak nor the metallated fr agmentation patterns are observed. Thermogravimetry shows the loss of ligands in stages, finally forming the stable metal oxides as the end product.