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 {[Ln­(bptcH)­(H2O)2]·H2O}n (Ln = NdIII (1), EuIII (2), GdIII (3), TbIII (4), DyIII (5), HoIII (6), or ErIII (7)) have been synthesized
by the solvothermal reactions of the corresponding lanthanide­(III)
picrates and 2,2′-bipyridine-3,3′,6,6′-tetracarboxylic
acid (bptcH4). 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 P1̅. The frameworks constructed from dinuclear lanthanide building
blocks exhibit one-dimensional double-stranded looplike chain architectures,
in which the bptcH3– ions adopted hexadentate coordination
modes. The EuIII (2) and TbIII (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.