Synthesis and Structures of Tris(cyclononatetraenyl) Rare-Earth Complexes [Ln(C₉H₉)₃] (Ln = Y, Gd, Tb, Dy, Ho, Er, Tm)

The article reports the synthesis and structural characterization of a series Ln(C9H9)3 complexes with cyclononatetraenyl (Cnt, C9H9) ligand (Ln = Y, Gd, Tb, Dy, Ho, Er, Tm). Yb Sm were not obtained, reaction potassium salt Cnt trivalent halide salts corresponding metals led to known bis-Cnt sandwich compounds Ln(C9H9)2. X-ray diffraction studies on show that is significantly bent in order accommodate large size while it maintains its aromaticity. When lanthanide ion decreases, does switch away but swings over metal maximize electrostatic interactions. 1H NMR UV–visible spectra, as well solid-state magnetism, recorded. spectroscopy highlights remarkable charge-transfer band Tm complex, ligand-based transitions are principally observed all other ions. magnetic behavior agrees ions, computations at CASSCF level confirm electronic structure.