Synthesis, structure, and magnetic properties of lanthanide ferrocenoylacetonates with nitrate and 2,2′-bipyridine ligands

<p>Ferrocenoylacetonate complexes of several lanthanides, [Ln(fca)₂(NO₃)(bpy)]·<i>n</i>MeC₆H₅ (Ln = Sm (<b>1</b>), Dy (<b>3</b>), Er (<b>4</b>), Yb (<b>5</b>), <i>n</i> = 1; Eu (<b>2</b>), <i>n</i> = 0.5; fca = FcC(O)CHC(O)Me; bpy = 2,2′-bipyridine), were synthesized and characterized by X-ray single-crystal analysis. Complexes <b>1</b>, <b>4,</b> and <b>5</b> are isostructural; <b>2</b> has a similar molecular structure with <i>cis</i>-disposition of fca ligands. The molecular structure of <b>3</b> is different, with <i>trans</i>-disposition of the fca ligands. Crystal lattices of the complexes are stabilized by <i>π</i>-stacking interactions. The Ln³⁺ ions in the complexes are eight-coordinate. According to mass spectroscopic data, the complexes are unstable in the gas phase. Magnetic properties of <b>2</b> and <b>4</b> were studied in a DC field; for <b>4</b>, AC studies were also carried out. The values of spin-orbital parameters obtained using two estimation methods for <b>2</b> are in satisfactory agreement. Slow relaxation of the magnetization was found for the Er complex.</p