Organic–inorganic hybrids assembled by bis(undecatungstophosphate) lanthanates and dinuclear copper(ii)–oxalate complexes

Abstract

A series of organic–inorganic hybrid compounds, K₂H₇[{Ln(PW₁₁O₃₉)₂}{Cu₂(bpy)₂(μ-ox)}]·xH₂O (Ln = La, x≈ 18 (1); Ln = Pr, x≈ 18 (2); Ln = Eu, x≈ 16 (3); Ln = Gd, x≈ 22 (4); Ln = Yb, x≈ 19 (5); bpy = 2,2′-bipyridine and ox = oxalate), have been isolated by the conventional solution method. Single-crystal X-ray diffraction studies reveal that compounds 1–5 are isomorphic and consist of one-dimensional chains, which are constructed by alternating bis(undecatungstophosphate) lanthanates [Ln(PW₁₁O₃₉)₂]¹¹⁻ and dinuclear copper(II)–oxalate complexes [Cu₂(bpy)₂(μ-ox)]²⁺. π–π interactions of the bpy ligands from adjacent chains lead to their three-dimensional structures. An analogue of potassium K₂H₉[{K(PW₁₁O₃₉)₂}{Cu₂(bpy)₂(μ-ox)}]·∼20.5H₂O (6) has also been obtained. The syntheses and structures of these compounds are reported here. Magnetic properties of 1, 2 and 3 are discussed as well. Attempts to crystallize similar compounds containing Co(II) and Ni(II) were unsuccessful.