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 Ph3 Ln(Bipy)Cl(μ 2 -Cl)] 2 (Ln = La ( I ), Pr ( II )) and mononuclear [Cp Ph3 Ln(Bipy)Cl 2 (THF)] (Ln = Er ( III ), Lu ( IV ), [Cp Ph3 Sc(Bipy)Cl 2 ] ( 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 )).