New 3d−4f Heterometallic Coordination Polymers Based on Pyrazole-Bridged Cu^IILn^III Dinuclear Units and Sulfate Anions: Syntheses, Structures, and Magnetic Properties

A series of 3d−4f heterometallic coordination polymers {[CuLn2(pdc)2(SO4)(H2O)6]·H2O}n (Ln = Tb (1), Dy (2); H3pdc = 3,5-pyrazoledicarboxylic acid), {[CuLn2(pdc)2(SO4)(H2O)4]·H2O}n (Ln = Sm (3), Eu (4), Gd (5), Tb (6), Dy (7)) have been hydrothermally synthesized and structurally characterized. The sulfate anions were in situ obtained from oxidation of CuSCN during the reaction. Complexes 1−7 are all constructed from pyrazole-bridged CuIILnIII dinuclear units and sulfate anions. Complexes 1 and 2 are isostructural and possess an infinite double-stranded tapelike 1D coordination framework. However, complexes 3−7 are interesting 3d−4f heterometallic coordination polymers with similar 3D framework structures. The magnetic properties of compounds 2, 4−6 have been investigated through the magnetic measurements over the temperature range of 1.8−300 K.