Structures and Properties of Porous Coordination Polymers Based on Lanthanide Carboxylate Building Units

A series of 3-D lanthanide porous coordination polymers, [Ln6(BDC)9(DMF)6(H2O)3·3DMF]n [Ln = La, 1; Ce, 2; Nd, 3], [Ln2(BDC)3(DMF)2(H2O)2]n [Ln = Y, 4; Dy, 5; Eu, 6], [Ln2(ADB)3(DMSO)4·6DMSO·8H2O]n [Ln = Ce, 7; Sm, 8; Eu, 9; Gd, 10], {[Ce3(ADB)3(HADB)3]·30DMSO·29H2O}n (11), and [Ce2(ADB)3(H2O)3]n (12) (H2BDC = benzene-1,4-dicarboxylic acid and H2ADB = 4,4′-azodibenzoic acid), have been synthesized and characterized. In 1−3, the adjacent LnIII ions are intraconnected to form 1-D metal−carboxylate oxygen chain-shaped building units, [Ln4(CO2)12]n, that constructed a 3-D framework with 4 × 7 Å rhombic channels. In 4−6, the dimeric LnIII ions are interlinked to yield scaffolds with 3-D interconnecting tunnels. Compounds 7−10 are all 3-D interpenetrating structures with the CaB6-type topology structure. Compound 11 is constructed by ADB spacers and trinulcear Ce nodes with a NaCl-type topology structure and a 1.9-nm open channel system. In 12, the adjacent CeIII ions are intraconnected to form 1-D metal−carboxylate oxygen chain-shaped building units, [Ln4(CO2)12]n, and give rise to a 3-D framework. Moreover, 6 exhibits characteristic red luminescence properties of EuIII complexes. The magnetic susceptibilities, over a temperature range of 1.8−300 K, of 3, 6, and 7 have also been investigated; the results show paramagnetic properties.