Studies on high-coordination complexes of dioxouranium(VI) with a Schiff base

A new series of six complexes of dioxouranium(VI) with the Schiff base N-[(4-N,N-bis-(2'-cyanoethyl)aminobenzylidene)amino]benzene (L) derived from 4-N,N-bis-(2'-cyanoethyl)aminobenzaldehyde and aniline and having the general compositions UO2X2L2 (X = Br, I, NCS, CH3COO or NO3) and UO2X2L4 (X = ClO4) were prepared: The complexes were characterized on the basis of elemental analyses, molecular weight measurements, conductivity measurements and infrared spectroscopy. X-ray powder diffraction data of two representative complexes are also presented. In all of these complexes the Schiff base ligand behaves as a monodentate neutral ligand which coordinates to the metal via the azomethine nitrogen atom. On the basis of the analyses the probable coordination number either 6 or 8 for U(VI) is suggested depending upon the nature of the anion present.