Structures and properties of porous coordination polymers based on lanthanide carboxylate building units.

A series of 3-D lanthanide porous coordination polymers, Ln(6)(BDC)(9)(DMF)(6)(H(2)O)(3)·3DMF [Ln = La, 1; Ce, 2; Nd, 3], Ln(2)(BDC)(3)(DMF)(2)(H(2)O)(2) [Ln = Y, 4; Dy, 5; Eu, 6], Ln(2)(ADB)(3)(DMSO)(4)·6DMSO·8H(2)O [Ln = Ce, 7; Sm, 8; Eu, 9; Gd, 10], {[Ce(3)(ADB)(3)(HADB)(3)]·30DMSO·29H(2)O}(n) (11), and Ce(2)(ADB)(3)(H(2)O)(3) (12) (H(2)BDC = benzene-1,4-dicarboxylic acid and H(2)ADB = 4,4'-azodibenzoic acid), have been synthesized and characterized. In 1-3, the adjacent Ln(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, Ln(4)(CO(2))(12), that constructed a 3-D framework with 4 × 7 Å rhombic channels. In 4-6, the dimeric Ln(III) 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 Ce(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, Ln(4)(CO(2))(12), and give rise to a 3-D framework. Moreover, 6 exhibits characteristic red luminescence properties of Eu(III) 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.