The organic ligands as template: the synthesis, structures and properties of a series of the layered structure rare-earth coordination polymers

A series of new 2D-layered structural rare-earth coordination polymers with the general formal [Ln(C8H4O5)(H2O)5]·(H2O)·(C8H4O5)1/2 (Ln ¼ Eu for (1); Gd for (2); Tb for (3); Dy for (4); and Er for (5)) have been yielded by hydrothermal synthesis. The coordination polymers crystallize in monoclinic space group C/2c with a ¼ 19:838ð16Þ; b ¼ 10:529ð8Þ; c ¼ 17:752ð14Þ A° , b ¼ 107:503ð14Þ8 for (1), with a ¼ 19:823ð7Þ; b ¼ 10:552ð4Þ; c ¼ 17:762ð6Þ A ° , b ¼ 107:443ð6Þ8 for (2), with a ¼ 19:770ð4Þ; b ¼ 10:519ð2Þ; c ¼ 17:698ð4Þ A ° , b ¼ 107:52ð3Þ8 for (3), with a ¼ 19:632ð2Þ; b ¼ 10:492ð2Þ; c ¼ 17:617ð3Þ A ° , b ¼ 107:470ð12Þ8 for (4), with a ¼ 19:648ð7Þ; b ¼ 10:480ð3Þ; c ¼ 17:598ð6Þ A ° , b ¼ 107:502ð6Þ8 for (5), respectively. And the metal ions (Ln3þ) are located in nine-member coordination environment. The carboxyl groups from 5-hydroxyisophthalate chelate the metal ions to form 1D helical cation chains. It is interesting that these helical cation chains are arranged to form 2D anion–cation layers by the uncoordinated ligands’ anions as template. And the luminescence properties of the rare-earth ions are studied in the paper. q 2003 Elsevier B.V. All rights reserved.