Syntheses and structures of three heterometallic coordination polymers derived from 4-pyridin-3-yl-benzoic acid

Three lanthanide-transition-metal coordination polymers, namely, [Er ₂L₆(H₂O)][Cu₂I₂] (1), [ErL₃][CuI] (2), and [Dy₂L₆(BPDC) _0.5(H₂O)₄][Cu₃I₂] (3) (HL=4-pyridin-3-yl-benzoic acid, H₂BPDC=4,4′- biphenyldicarboxylic acid) have been made by reacting Ln₂O ₃ and CuI with HL at different temperatures under hydrothermal conditions. All the complexes are characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction, respectively. 1-3 all construct from dimeric {Ln₂} and {Cu₂} units and exhibit two types of the structural features: 1 is a two-dimensional layer, 2-3 are three-dimensional frameworks. Interestingly, the in situ formation of the BPDC ligand is found in the structure of 3. The distinct architectures of these complexes indicated that the reaction temperature plays an important role in the formation of higher dimensional coordination polymers.