Molecular Magnets Based on Mononuclear Aqua and Aqua-Chloro Lanthanide (Tb, Dy, Er, Yb) Complexes with Bipyridine

The complexes [Tb(Bipy)2(H2O)2Cl2]Cl (I), [Ln(Bipy)(H2O)6]Cl3·2H2O·0.5Bipy (Ln = Dy (II), Yb (IV)), [Er(Bipy)2(H2O)3Cl]Cl2·2H2O (III), and [Yb(Bipy)(H2O)6]Cl3 (V) were prepared using salts LnCl3·6H2O (Ln = Tb, Dy, Er, Yb) and 2,2'-bipyridine (Bipy). The structure of complex V was determined by X-ray diffraction (CIF file CCDC no. 2024688). Magnetic characteristics of the complexes indicate that the replacement of water molecules in the coordination sphere of aqua chlorides by bidentate Bipy ligand gives single-molecule magnets with significant barriers for magnetization reversal, especially in the case of ytterbium compound, ΔE/kB([Yb(Bipy)(H2O)6]Cl3·2H2O·0.5Bipy) = 43 K.