URANYL(VI) AND LANTHANUM(III) COMPLEXES WITH FUNCTIONALIZED MACROCYCLIC AND MACROACYCLIC SCHIFF-BASES

Acyclic Schiff bases have been prepared by [2+1] condensation of 2,6-diformyl-4-chlorophenol and H2NCH2[CH(2)XCH(2)]nCH2NH2(n=O H-2-I; X=NH, S, O n=1 H-2-II ... H-2-IV; X=O n=2 H-2-V; X=O n=3 H-2-VI). The related uranyl(VI) and lanthanum(III) complexes have been synthesized by reaction of the preformed ligands with the appropriate salt or by the template procedure, in the presence of base. No base was employed in the preparation of lanthanum(III) complexes, La(H-2-II)(NO3)(3), La(H-2-IV)(NO3)(3) where the Schiff bases coordinate as neutral chelate ligands. These acyclic complexes have been used for further condensation, and symmetric and asymmetric cyclic complexes have been obtained by their reaction with the polyamines H2NCH2[CH(2)XCH(2)]nCH2NH2 or with 4,4'-diaminodibenzo-18-crown-6. By reaction with 4-aminobenzo-15-crown-5 or 2-amino-methyl-15-crown-5, the same acyclic complexes give rise to functionalized complexes bearing crown-ether moieties. Analogously, the acyclic ligand H-3-IXX, prepared by condensation of 2,6-diformyl-4-chlorophenol and tris(aminoethyl)amine, forms mono-and homodinuclear lanthanum(III) complexes, which may undergo further condensation when reacted with primary functionalized amines.