Linear Tetranuclear Lanthanide Cymantrenecarboxylates with Diethylene Glycol Ligand: Synthesis, Magnetism, and Thermolysis

• Published in: European journal of inorganic chemistry 2021-01, Vol.2021 (2), p.147-155
• Main Authors: Koroteev, Pavel S., Ilyukhin, Andrey B., Babeshkin, Konstantin A., Belova, Ekaterina V., Gavrikov, Andrey V., Efimov, Nikolay N.
• Format: Article
• Language: English
• Subjects: Antifreeze solutions; Argon; Cymantrenecarboxylate; Dysprosium; Gadolinium; Heterometallic complexes; Inorganic chemistry; Lanthanides; Magnetic measurement; Magnetic properties; Magnetism; Magnets; Mixed oxides; Neodymium; Thermal decomposition; Thermochemistry
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202000700

Exchange reactions of LnCl3 and CymCO2K in aqueous‐organic medium in the presence of diethylene glycol (DEG) bring about isostructural tetranuclear cluster complexes with linear core, [Ln4(CymCO2)12(O(CH2CH2OH)2)2(H2O)4] ⋅ 2THF (Ln=Nd (1), Gd (2), Tb (3), Dy (4), Ho (5); Cym=(η5‐C5H4)Mn(CO)3). The complexes have centrosymmetric structure and contain two types of Ln3+ coordination centers. Thermal decomposition of the complexes under argon and air atmospheres was studied; in the latter case it brings about mixed oxides LnMn2O5 as one of the products. The complexes 1–5 were characterized by dc‐ and ac‐magnetic measurements. Complexes of Nd, Gd, and Dy exhibit the properties of single‐molecule magnets (SMMs) with remagnetization barriers Δeff/kB of 14 K for 1 under 2500 Oe dc‐field, 13 K for 2 under 1500 Oe dc‐field, and with two barriers, 18 and 19 K, for 4 in zero field. The presence of field‐induced slow relaxation of the magnetization detected for the complex 2 is a rare case for Gd complexes. Lanthanide and cymantrenecarboxylate ions combine in aqueous‐organic media with diethylene glycol to form carboxylate clusters having tetranuclear core and organometallic shell. Dy complex is a zero‐field SMM, while Nd and Gd complexes are field‐induced SMMs, which is unusual for Gd complexes. Thermolysis of compounds in air gives Mn3O4 and multiferroics LnMn2O5.