Structural Diversity of Heteroleptic 1,2,4-Triphenylcyclopentadienyl-Bipyridine Complexes of Rare Earth Metals

The reaction of triphenylcyclopentadienyl potassium and bipyridine with lanthanum, praseodymium, erbium, lutetium, and scandium chloride tetrahydrofuranates results in the formation of binuclear [Cp^Ph3Ln(Bipy)Cl(μ₂-Cl)]₂ (Ln = La (I), Pr (II)) and mononuclear [Cp^Ph3Ln(Bipy)Cl₂(THF)] (Ln = Er (III), Lu (IV), [Cp^Ph3Sc(Bipy)Cl₂] (V) complexes (Cp^Ph3 = 1,2,4-triphenylcyclopentadienyl, Bipy = bipyridine). The decrease in the REE radius in the series La…Sc results in the formation of mononuclear instead of binuclear complexes and in a decrease in the coordination number of the central ion. The coplanar arrangement of two different π-systems gives rise to stacking interactions between the triphenylcyclopentadienyl ligand and bipyridine. The molecular structure of complexes I–V was established by X-ray diffraction analysis (CCDC nos. 2308609 (I), 2308608 (II), 2308610 (III), 2308611 (IV), 2308607 (V)).