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

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