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

A series of 3d-4f heterometallic coordination polymers {[CuLn(2)(pdc)(2)(SO4)(H2O)(6)]center dot H2O}(n) (Ln = Tb (1), Dy (2); H(3)pdc = 3,5-pyrazoledicarboxylic acid), {[CuLn(2)(pdc)(2)(SO4)(H2O)(4)]center dot H2O}(n) (Ln = Sm (3), Eu (4), Gd (5), Th (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 Cu(II)Ln(III) dinuclear units and sulfate anions. Complexes 1 and 2 are isostructural and possess an infinite double-stranded tapelike I D 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.