cg401365x_si_005.cif (11.92 kB)

Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln–Pyridine-3,5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand

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posted on 02.01.2014, 00:00 by Xiao Wang, Quan-Guo Zhai, Shu-Ni Li, Yu-Cheng Jiang, Man-Cheng Hu
Nine members of the novel Ln–pyridine-3,5-dicarboxylate coordination polymer family, namely, [Ln­(PDC)­(GA)]n (Ln = Gd (1), Tb (2), Dy (3), Er (4)), [Ln­(PDC)­(OAc)­(H2O)]n·nH2O (Ln = Sm (5), Eu (6), Gd (7)), [Gd­(PDC)­(OAc)­(H2O)2]n·nH2O (8), and [Tb­(PDC)1.5­(H2O)]n (9) (PDC = pyridine-3,5-dicarboxylate, GA = glycolate, OAc = acetate), have been successfully obtained by carefully regulating the ancillary ligand or reaction temperatures. Complexes 14 are isomorphous two-dimensional networks generated by Ln–glycolate chains and bridging PDC ligands. When the HOAc was utilized instead of glycolic acid, isomorphic three-dimensional compounds 57 were isolated. The Ln3+ atoms are first bridged by acetate anions to give dinuclear clusters, which are extended by nearby six PDC ligands forming a 3D (3,6)-connected flu-topological framework. Notably, the increase of reaction temperature from 160 to 180 °C during the synthesis of compound 7 led to compound 8, the other 3D (3,6)-connected structure on the base of dinuclear subunits with rtl topology. Furthermore, the absence of HOAc introduced the formation of compound 9, in which each binuclear cluster links adjacent eight PDC anions to give a 3D (3,8)-connected tfz-d topological structure. The elemental analyses, XRPD, FT-IR, and TGA were also investigated to characterize compounds 19. Furthermore, solid-state photoluminescence measurements show that these Ln–pyridine-3,5-dicarboxylate coordination polymers produce strong emissions at room temperature.