Synthesis,Crystal Structures And Recognition Properties Of Metal Phosphonate Coordination Polymers

In this work,the six novel metal phosphonates functional materials by employing3–ammonium–1–hydroxypropylidene–1,1–bisphosphonate(H₄apd),3–pyridyl–CH₂N(CH₂PO₃H₂)₂(H₄L),p–xylylenediphosphonic acid(H₄pmd),4–phosphono–benzoicacid(4–cpp H₃),as phosphonic acid ligands have been synthesized under hydrothermal conditions.All six compounds were structurally characterized by X-ray single-crystal diffraction,X-ray powder diffraction,infrared spectroscopy and thermogravimetric analysis.The luminescent properties of the synthesized compounds 1 and 7 have been studied.The compounds chemical formulas are listed as follow:(1)[Zn₂(pmd)(H₄pmd)_0.5(1,10–phen)₂]?H₂O(2)[Zn(H₂pmd)(1,10–phen)₂]?H₄pmd(3)[Cd(H₃apd)₂](4)[Cd(H₃apd)₂]?2H₂O(5)[Pb(H₂apd)]?2H₂O(6)Na₂[La₂(L)(C₂O₄)₃(H₂O)₂](7)[Zn₂(4–cpp H)(4–cpp H₂)₂(2,2?–bipy)]Compound 1 is synthesized by using p–benzyldiphosphonic acid(H₄pmd)as the phosphonate ligand,and 1,10–phen as the second metal linker.X?ray diffraction analysis shows that compound 1 features 3D network structure,and the compound 2 forms a 1D chain structure by hydrogen bonding.Compounds 3?5 are synthesized by using3–ammonium–1–hydroxypropylidene–1,1–bisphosphonate(H₄apd)as the phosphonate ligand.Compound 6 has been synthesized by using 3–pyridyl–CH₂N(CH₂PO₃H₂)₂(H₄L)as phosphonic acid ligand,it shows 3D framework structure.The luminescent properties of the synthesized compounds 1 and 7 are good candidate for fluorescent identification materials.The luminescence recognition properties of compound 1 for the sensing of 4?nitrophenol,and compound 7 for sensing of mercury ion were systematically investigated.The recognition mechanism of compounds 1 and 7 are discussed in detail.