Synthesis, crystal structures and luminescent properties of two 4 d–4 f Ln–Ag heterometallic coordination polymers based on anion template

Abstract

Two new 4 d–4 f Ln–Ag heterometallic coordination polymers, {[ Ln 3Ag 5(IN) 10(H 2O) 7]·4(ClO 4)·4(H 2O)} n ( Ln=Eu ( 1) and Sm ( 2), HIN=isonicotinic acid), have been synthesized under hydrothermal conditions by reactions of Ln 2O 3, AgNO 3, HIN and HClO 4, and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. It is proved that HClO 4 not only adjusts the pH value of the reaction mixture, but also acts as anion template. The structure determination reveals that 1 and 2 are isostructural and feature a novel two-dimensional (2D) layered hetrometallic structure constructed from one-dimensional Ln–carboxylate chains and pillared Ag(IN) 2 units. The 2D layers are further interlinked through Ag⋯Ag and Ag⋯O(ClO 4 −) multiple weak interactions, which form a rare Ag–ClO 4 ribbon in lanthanide–transition metal coordination polymers, to give rise to a three-dimensional supramolecular architecture. Moreover, the luminescent properties of these two compounds have also been investigated at room temperature.