Syntheses, Crystal Structures, And Properties Metal Phosphonates With Two Ligands

In this work, we have devoted effort toward hydrothermal synthesis of metal phosphonate coordination polymers by using (4-carboxypiperidyl)-N-methylenephosphonic acid (H2O3PCH2-NC5H9-COOH), and C6H5CH2(NH2)PO3H2as ligands to obtain possible new types of materials with potential applications. Eight novel metal phosphonate coordination polymers are hydrothermally synthesized by using the second metal linkers. All compounds were structurally characterized by X-ray single-crystal diffraction, X-ray powder diffraction, IR spectroscopy and thermogravimetric analysis. Meanwhile, the luminescent properties of compounds1,2,4,5,6,7and8have also been studied.Three kinds of second metal linker, including5-sulfoisophthalic acid monosodium salt (NaH2bts),5-sulfosalicylic acid (H3SSC) and1,4-benzenedicarboxylic acid (H2bdc) were used in the synthesis of metal phosphonate coordination polymers. These compounds are all three-dimensional open-framework. The chemical constitution formulas are listed as follow:(1)Pb4[(HL)(O3SC6H3(COO)2)2(H2O)]·2H2O(2)Pb3[(HL)2(O3SC6H3(COO)OH]·2H2O(3)Pr3[(H2L)(HL)2(OOCC6H4COO)2(H2O)]·7H2O(4) Sm3[(H2L)(HL)2(OOCC6H4COO)2(H2O)]·7H2O(5)Eu3[(H2L)(HL)2(OOCC6H4COO)2(H2O)]·7H2O(6)Gd3[(H2L)(HL)2(OOCC6H4COO)2(H2O)]·7H2O(7)Tb3[(H2L)(HL)2(OOCC6H4COO)2(H2O)]·7H2O(8) Zn[(HL’)(OOCC6H4COO)0.5]By using (4-carboxypiperidyl)-N-methylenephosphonic acid as the phosphonate ligand and by introduction of5-sulfoisophthalic acid monosodium salt (NaH2bts) and5-sulfosalicylic acid (H3ssc) as the second metal linkers, compounds1and2are synthesized. X-ray diffraction analysis exhibits that compounds1and2feature3D framework structures. Compounds3-7which are synthesized by using (4-carboxypiperidyl)-N-methylenephosphonic acid as the phosphonate ligand and1,4-benzenedicarboxylic acid as the second metal linker are isomorphous and feature a3D open-framework structure. Compounds5and6were not obtained single crystals suitable for X-ray structural analysis, however, X-ray powder diffraction analysis indicates compounds5and6are isomorphous and feature a3D pillared-layered architecture, which is the same as the structure of compounds3,4and7. Compound8is synthesized by using C6H5CH2(NH2)PO3H2as the phosphonate ligand and1,4-benzenedicarboxylic acid as the second metal linker. X-ray diffraction analysis shows that the compound8is3D framework structure.The thermal analysis of these compounds indicates that they form the stabilized framework structure. The luminescence analysis indicates that compounds1,2and8are good candidate for luminescent material. Compounds4,5,6and7which exhibit characteristic lanthanide-centered luminescence are new examples of luminescent rare-earth phosphonates.