Synthesis and characterization of dioxouranium(VI) complexes of polydentate ligands

The polydentate ligands, N,N'-ethylene-bis-(2- aminobenzamide) [EBAB], N,N' -propylene-bis-(2-aminobenzamide) [PBAB], N,N'-(o-phenylene)-bis-(2-aminobe nzamide) [PhBAB], N,N'-ethylene-bis-(3-carboxypropenamide) [EBCP], N,N'-pro pylene-bis-(3-carboxypropenamide) [PBCP] and 1-(2'-hydroxyphenyl)-3-phenyl- 1,3-propane-dione [HPPPD] react with uranyl acetate to form crystalline com plexes with different coordination environments. The geometries of the comp lexes have been confirmed with the help of the spectroscopic methods, condu ctance measurements and thermal studies. The neutral tetradentate ligands ( EBAB, PBAB and PhBAB) form eight coordinate hexagonal bipyramidal complexes , while anionic tetradentate ligands (EBCP and PBCP) and tridentate ligand (HPPPD) form seven coordinate pentagonal bipyramidal complexes.