A simple synthesis and a structural survey of homoleptic rare earth(III) 2,6-diphenylphenolates

Abstract

Reactions of 2,6-diphenylphenol (HOdpp) and rare earth metals, in the presence of mercury, at elevated temperatures in sealed tubes followed by extraction with toluene yielded homoleptic tris(aryloxo)lanthanoid(III) complexes, [Ln(Odpp)₃] (Ln = Y (1), La (2), Ce (3), Pr (4), Nd (5), Gd (6), Ho (7), Er (8), Lu (9)). Single crystal X-ray diffraction studies of 1–4 and 9 established monomeric structures with the coordination sphere comprising a triangular array of Odpp oxygen atoms with capping phenyl groups above and below. In the isomorphous (triclinic P1) 1, 3, 4 and 9, there are additional intramolecular π-interactions of the phenyl substituents with the metals (η⁶-Ph–Ln and η¹-Ph–Ln). The cell parameters for 2, though similar, suggest a different form, and the structure has additional intramolecular η⁶-Ph–La and η³-Ph–La interactions with the capping phenyl groups near parallel.