Four novel lanthanide(III) coordination polymers with 3D network structures containing 2-fold interpenetration

Four novel lanthanide(III) coordination polymers [Ln(L)1.5(H2O)2]·5H2O [Ln = Sm (1), Eu (2), Tb (3), Dy (4)] have been hydrothermally synthesized by the reaction of 1,2-bis[4-amino-5-carboxylmethylthio-(1,2,4-triazol-3-yl)]ethane (H2L) with lanthanide(III) salts, and structurally characterized by single crystal X-ray diffraction. Polymers 1–4 are isostructural, in which all the LnIII atoms are nine-coordinated and the carboxylate groups adopt three different coordination modes (bidentate chelate, bidentate bridging, bidentate chelate bridging) to connect LnIII atoms. These polymers exhibit 3D network structures with 2-fold interpenetration, in which intriguing 1D channels are observed. Besides, the spectra properties of the title polymers are investigated, the strong luminescence characteristics of 2–3 are found.