Dioxouranium(VI) and Thorium(IV) Complexes of a Linear Pentadentate Schiff Base Ligand

Abstract
The linear, potentially pentadentate Schiff base ligand bis(salicylidene)aminodiethylenetriamine, H2L (donor set N3O2), derived from salicylaldehyde and diethylenetriamine, when reacted with dioxouranium(VI) and thorium(IV) forms complexes of the type UO2(H2L)X2 (X = Cl, I, NO3, 0.5 SO4) and Th(H2L)X4 (X = Cl, I, NCS, NO3). The neutral ligand molecule and not the deprotonated, dinegative anion is involved in bonding. The coordination number for all these complexes is found to be 9. With the metal perchlorates the ligand behaved as a deprotonated, dinegative anion to form the 7-coordinated UO2(L) and the 9-coordinated Th(L)(ClO4)2 complexes. The latter compound involves the ClO4 groups in bidentate coordination. All these complexes were characterized by elemental analyses, electrical conductivity in non-aqueous solvents and vibrational spectra.