A Series of CuII-LnIII Metal-Organic Frameworks Based on 2,2'-Bipyridine-3,3'-dicarboxylic Acid: Syntheses, Structures, and Magnetic Properties

A series of Cu(II)Ln(III) heterometallic metalorganic frameworks (HMOFs), displaying three types of structures with the formulas of {[Ln(2)Cu(BDPC)(4)(H2O)(6)]center dot 9H(2)O}(n) (Ln = La, 1; Pr, 2; Nd, 3; BPDC2 = 2,2'-bipyridine-3,3'-dicarboxylate), {[Ln(2)Cu(2)(BPDC)(5)(H2O)(6)]center dot 9H(2)O}n (Ln = Pr, 4; Nd, 5; Sm, 6; Eu, 7; Gd, 8; Tb, 9) and [DyCu3(BPDC)(4)(NO3)(H2O)(6)](n) (10), have been successfully synthesized and well characterized. Single crystals available for X-ray diffraction measurements were carried out for MOFs 3, 7, 9, and 10. Powder X-ray diffraction and Fourier transform infrared analysis demonstrate the isomorphism for MOFs 13, as well as MOFs 49. The BPDC2 ligand herein exhibits seven different coordination modes to link metal centers for the construction of different three-dimensional structures. The structures of the three types of Cu-II-Ln(III) HMOFs can be described topologically with the Schlafli symbol {3 center dot 6 (2)}{3 (2) center dot 6 (6) center dot 7 (3 center dot)8 (3)center dot 9}{6 (2) center dot 7}, {4 center dot 6 (2)}(2){4 (2) center dot 6 (4) center dot 8 (6)center dot 10 (3)}{6 center dot 8 (2)}(2), and {4 center dot 8 center dot 9}(2){6 center dot 8 center dot 9}(2){6 center dot 8 (2)center dot 9 (3)}{8 (2)center dot 9}(2), of which the latter two are new topologies. The static magnetic properties of the 10 HMOFs and dynamic magnetic properties of 9-Tb2Cu2 and 10-DyCu3 have been studied.