Lanthanide complexes of potentially heptadentate Schiff base ligands

Abstract

The potentially heptadentate trianionic Schiff base ligands derived from tris(2-aminoethyl)amine and 3 mol of (substituted) salicylaldehyde react with lanthanide metal nitrates to form neutral 1:1 compounds of formula Ln(X-Saltren). Physicochemical measurements are described for the following complexes: Ln = La, Pr, Nd, Eu, Gd, Dy, Ho, Yb, X = 3,5-Cl 2 ; Ln = La, X = 5-Cl and 5-NO 2 ; and the analogous complexes, M = Sc, Y, Co, X = 3,5-Cl 2 . Discussion of the spectroscopic data focuses on far infrared ν(Ln—O) and ν(Ln—N) bands, 1 H nmr pseudocontact shifts and hypersensitive f–f transitions.