Synthesis and Characterization of Yttrium(III), Lanthanum(III), and Holmium(III) Complexes with a Heptadentate Schiff Base Ligand

Abstract

Yttrium(III), lanthanum(III), and holmium(III) complexes with tris‐(salicylideneamino)triethylenetetramine have been synthesized and characterized by elemental and spectral analyses as well as x‐ray crystal diffraction. The FAB and TOF (time‐of‐flight) mass spectra reveal that the ligand acts as a heptadentate and that the metal versus ligand stoichiometry is 2:2. The structure of the lanthanum(III) complex has been determined by x‐ray single crystal diffraction. The lanthanum(III) ion is coordinated through the four nitrogen and the four oxygen atoms of the two ligands to form an eight‐coordinate configuration. The two lanthanum(III) ions are bridged by the two phenolate oxygen atoms in the complex. The structure is similar to that of the ligand containing p‐bromo substituents. The proton NMR spectra also show that the lanthanum(III) complex is a dimer.