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Construction of Lanthanide Metal−Organic Frameworks by Flexible Aliphatic Dicarboxylate Ligands Plus a Rigid m-Phthalic Acid Ligand

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posted on 05.09.2007, 00:00 by De-Xin Hu, Feng Luo, Yun-Xia Che, Ji-Min Zheng
Six rare earth coordination polymers, namely, [La2(H2O)4(Hip)2(L1)2]·4H2O (1) (H2L1 = succinate acid, H2ip = m-phthalic acid), Ln(H2O)(ip)0.5(L2) (Ln = Gd (2), Dy (3), Y (4), H2L2 = glutaric acid), [Sm2(H2O)2(ip)(L2)2]·3H2O (5), and Er(H2O)2(ip)(L3)0.5 (6) (H2L3 = adipic acid), have been synthesized hydrothermally from the self-assembly of the earth ions (Ln3+) with flexible aliphatic dicarboxylate ligands (H2L1, H2L2, H2L3) and the rigid m-phthalic acid ligand (H2ip). Compounds 2, 3, and 4 show the common α-Po nets built on six-connected dinuclear Ln2 units (Ln2 = Gd2, Dy2, and Y2). The structure of compound 5 can be viewed from the tetrahedral sra-nets based on Sm−O−C rods. In compounds 1 and 6, the La−O−C rods and Er−O−C rods are in turn linked by organic spacers to give two dimensional (2D) square nets, which can be further extended to three-dimensional (3D) supramolecular frameworks via hydrogen-bonding contacts. Furthermore, the thermogravimetric analyses of all the compounds were carried out.