Hydrothermal synthesis and crystal structure of two new lanthanide coordination polymers with 1,2-phenylenediacetate

Two new compounds {[Ln(2)(1,2-pda)(3)(H2O)(2)]center dot 2H(2)O}n (1,2-H(2)pda = 1,2-phenylenediacetic acid, Ln = Tb, 1; Ho, 2) were prepared by hydrothermal reaction and characterized by X-ray crystallography. The Ln(3+) is nine-coordinate by eight oxygen atoms of six 1,2-pda ligands and one oxygen of water. Ln(3+) ions are bridged by 1,2-pda ligands via bridging/chelating-bridging pentadentate and chelating-bridging/chelating-bridging hexadentate coordination to form 3-D framework structures. Complex 1 emits strong green fluorescence corresponding to D-5(4) -> F-7(j) (j = 6-3) transitions of the Tb3+.