Mononuclear and binuclear lanthanide acetates with chelating and bridging triethanolamine ligands

Abstract The interaction of lanthanide acetates with triethanolamine in pyridine medium yields mononuclear cationic complexes [Ln(teaH3)2(MeCOO)](MeCOO)2·0.5Py (teaH3 = N(CH2CH2OH)3, Py – pyridine) in cases Ln = Ce (1) and Pr (2), and binuclear heteroleptic complexes containing deprotonated triethanolamine [Ln2(MeCOO)4(teaH2)2] (Ln = Gd (3), Dy (4), Ho (5), and Er (6)). In the complexes of the first type, tetradentate chelating triethanolamine is a neutral ligand, while the metal core of the complexes of the second type is formed of lanthanide ions and bridging oxygen atoms of deprotonated teaH3. In the processes of thermal decomposition of complexes, systematic changes related to the character of the Ln3+ ions are noted. The complexes 1–6 were characterized by dc magnetic measurements, the Dy, Ho, and Er derivatives were also investigated in ac field. In the Gd complex, antiferromagnetic interactions between the Gd3+ ions were found. Results for complex 3, along with the literature data for eight complexes with the [Gd2O2] core, allowed to complement and to confirm the correlation between the value of the exchange interaction energy JGd–Gd′ and the interionic distances DGd…Gd′ for the complexes of this type that we found earlier. Complex of Dy exhibits field-induced slow relaxation of the magnetization.