A fresh look at the structural diversity of dibenzoylmethanide complexes of lanthanides

An analysis of known synthetic methods for dibenzoylmethanide (dbm(-)) complexes of lanthanides of different nuclearity, viz. [Ln(dbm)(3)(H2O)], [Ln(4)(dbm)(10)(OH)(2)], [Ln(5)(dbm)(10)(OH)(5)] and [KLn(dbm)(4)](n) (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) has been carried out. These methods have been optimized, the range of lanthanides for the compounds extended, and novel complex species, viz. [KLn(Me2CO)(dbm)(4)](2) (Ln = Eu, Dy, Yb) and [Nd-3(dbm)(8)(OH)(H2O)], have been produced. The nature of the lanthanides in some cases affects the composition of the products formed. The compound [KEu(Me2CO)(dbm)(4)](2) in solution can transform to [KEu(dbm)(3)(OBz)](n), containing benzoate (OBz(-)). For the seven new complexes, the crystal structures have been determined by X-ray diffraction. Photoluminescent properties of the europium complexes have been studied. Their composition and structure influence the emission band shape and quantum yields. Two solid solutions of heterolanthanide complexes [ErxYb5-x(dbm)(10)(OH)(5)] (x = 1.2, 2.0) have been prepared, as shown by high-resolution powder XRD analysis.