Nature of bonding in mixed chelate complexes of dioxouranium(VI) with benzhydroxamic Acid

Several anions and coordinating amines have been successfully employed along with benzhydroxamic acid (BH) for chelation and subsequent expansion of coordination number of dioxouranium(VI) in the established bis complex of dioxouranium(VI) with BH. DTA and TG data of the mixed chelate complexes indicate the following order of relative stabilities:acetato = iodo bipyridyl less than carbonato less than chloro=phenanthroline less than urea less than nitrato less than sulphato. Far infrared data of the complexes have been utilised to predict geometry of the complexes. The lowering in symmetry of the anions as revealed by the IR data indicates their coordination.The broad and split ν3 (O-U-O) in phenanthroline and bipyridyl complexes favours bridged structures. The linearity of UO22+ moiety in the complexes has been suggested. (author)