Two new 2p–3d–4f heterometallic coordination polymers based on 3,5-pyrazoledicarboxylic acid: synthesis, crystal structures and magnetic properties

Two new 2p–3d–4f heterometallic coordination polymers, [NaCuGd(pdc)2(H2O)7 ∙ 2H2O]n (1) and [NaCuEu(pdc)2(H2O)7 ∙ 2H2O]n (2), have been synthesized based on 3,5-pyrazoledicarboxylic acid (H3pdc). Single-crystal X-ray diffraction analysis reveals that complexes 1−2 are isostructural and both of them display an infinite two-dimensional brickwall-like layer structure consisting of three metal ions and bridged pyrazoledicarboxylate ligands. Magnetic properties of the complexes have been investigated in detail. Furthermore, free-ion approximation was used to fit the magnetic data and a good theory-experiment agreement was obtained for both 1 and 2.