Three isophthalate coordination polymers with formula of [Ln2(ip)3(H2O)2]n•n(H2O) (H2ip＝isophthalic acid, Ln＝Pr (1), Eu (2), n＝0; Ln＝Ho (3), n＝1), were prepared under a hydrothermal condition and characterized by elemental analysis, infrared spectrum, thermal analysis and X-ray single crystal diffraction techniques. All these complexes crystallized in a monoclinic crystal system, P2(1)/n space group. Complexes 1 and 2 are isostructural with dinuclear Ln(III) units in which two metal ions lie in seven- and eight-coordinated environments, respectively, belonging to penta bipyramid and bicapped trigonal prism geometries, while complex 3 is slightly different with the complexes 1 and 2, in which Ho(III) centers locate in monocapped and bicapped trigonal prism geometries, respectively. In these complexes, adjacent metal ions are linked by ip ligands causing right- and left-handed helical chains to form a two dimensional network. Fluorescence spectrum in solid state of complex 2 and its dehydrated products showed strong fluorescence properties.

Key words: isophthalic acid, lanthanide complex, crystal structure, fluorescence spectrum