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

Two new 4d–4f Ln–Ag heterometallic coordination polymers, {[Ln3Ag5(IN)10(H2O)7]·4(ClO4)·4(H2O)}n (Ln=Eu (1) and Sm (2), HIN=isonicotinic acid), have been synthesized under hydrothermal conditions by reactions of Ln2O3, AgNO3, HIN and HClO4, and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. It is proved that HClO4 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(ClO4−) multiple weak interactions, which form a rare Ag–ClO4 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.