Syntheses, Structures, Luminescence, and Magnetic Properties of One-dimensional Lanthanide Coordination Polymers with a Rigid 2,2′-Bipyridine-3,3′,6,6′-tetracarboxylic Acid Ligand

A series of novel one-dimensional (1-D) lanthanide coordination polymers (CPs), with the general formula an(bptcH)(H2O)(2)]center dot H2O)(n) (Ln = Nd-III (1), Eu-III (2), Gd-III (3), Tb-III (4), Dy-III (5), Ho-III (6), or Er-III (7)) have been synthesized by the solvothermal reactions of the corresponding lanthanide(III) picrates and 2,2'-bipyridine-3,3',6,6'-tetracarboxylic acid (bptcH(4)). These polymers have been structurally characterized by single-crystal X-ray diffraction, IR, PXRD, thermogravimetric (TGA), and elemental analysis. Coordination polymers 1-7 are isostructural; they possess the same 3D supramolecular architectures and crystallize in triclinic space group P (1) over bar. The frameworks constructed from dinuclear lanthanide building blocks exhibit one-dimensional doublestranded looplike chain architectures, in which the bptcH(3-) ions adopted hexadentate coordination modes. The Eu-III (2) and Tb-III (4) polymers exhibit characteristic photoluminescence in the visible region. The magnetic properties of polymers 2, 3, and 5 have been investigated through the measurement of their magnetic susceptibilities over the temperature range of 1.8-300 K.