One-dimensional lanthanide coordination polymers supported by pentadentate Schiff-base and diphenyl phosphate ligands: single molecule magnet behavior and photoluminescence

Abstract

Four lanthanide complexes formulated as [Ln₂(DAPBH)₂(DPP)₃(CH₃OH)](NO₃)(ClO₄)₂·3CH₃OH [Ln = Tb (1), Dy (2), Er (3) and Yb (4), DAPBH = 2,6-diacetylpyridine bis(benzoyl hydrazone), DPP = diphenyl phosphate] have been synthesized and investigated. Crystallographic studies demonstrate that these complexes are composed of one-dimensional (1D) chains with alternating eight- and nine-coordinate Ln(III) ions. The coordination geometries around Ln(III) centers can be described as a triangular dodecahedron and muffin. Magnetic measurements show the presence of weak ferromagnetic interactions in complex 2. Complexes 3 and 4 display field-induced single molecule magnet (SMM) behaviour, whereas such behaviour was not found in the Tb(III) and Dy(III) analogues. Ligand-centered luminescence was observed in complexes 1 and 2, while the characteristic emission spectrum of Yb(III) ion was detected in complex 4.