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.

Keywords:

• Yttrium(III), lanthanum(III), and holmium(III) complexes
• Heptadentate
• Schiff base
• Time‐of‐flight

Acknowledgments

We are grateful to the Center for Instrumental Analysis, Kyushu Institute of Technology for elemental analyses, mass spectra and ¹H NMR spectra. We also thank Prof. Y. Hisaeda and Dr. I. Aritome at Kyushu University for x‐ray single crystal analyses and TOF mass spectra.