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

Exchange reactions of LnCl 3 and CymCO 2 K in aqueous‐organic medium in the presence of diethylene glycol (DEG) bring about isostructural tetranuclear cluster complexes with linear core, [Ln 4 (CymCO 2 ) 12 (O(CH 2 CH 2 OH) 2 ) 2 (H 2 O) 4 ] ⋅ 2THF (Ln=Nd ( 1 ), Gd ( 2 ), Tb ( 3 ), Dy ( 4 ), Ho ( 5 ); Cym=(η 5 ‐C 5 H 4 )Mn(CO) 3 ). The complexes have centrosymmetric structure and contain two types of Ln 3+ coordination centers. Thermal decomposition of the complexes under argon and air atmospheres was studied; in the latter case it brings about mixed oxides LnMn 2 O 5 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 Δ eff / k B 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.