Synthesis, crystal structure, and magnetic properties of two 3d–4f heterometallic coordination polymers

Abstract

Two new 4f–3d heterometallic coordination polymers, [Gd 2 IIICo II(pydc) 3(ox)(H 2O) 4)·2H 2O] ( 1) and [Dy IIICu II(pydc) 2(ox) 1/2(H 2O) 2·H 2O] ( 2) (pydc = pyridine-2,5-dicarboxylate anion, ox = oxalate dianion) were successfully synthesized under hydrothermal condition. Structure and magnetism of the two coordination polymers were characterized by single crystal X-ray diffraction and Quantum Design (MPMS) SQUID magnetometer. In both compounds, metal centers were connected by double ligand bridges. In 1 the gadolinium ions were linked in sheets by O C O ligand bridges and these sheets were connected by separated cobalt coordination spheres to generate the overall 2-D structure. In 2 the dysprosium centers were constructed into one dimensional chain by O C O bridges from pydc ligand bridges and these chains were linked by oxalate bridges to form sheets and different sheets were connected by copper coordination planes. The copper centers in 2 were linked in chain by elongated O C O brides and the chains were connected by hydrogen bond to generate 3-D structure. Magnetic properties of the two complexes were investigated by variable temperature magnetic susceptibility. The magnetic data suggest that overall antiferromagnetic interactions are present in the two compounds.