From 1D zigzag chains to 3D chiral frameworks: synthesis and properties of praseodymium(iii) and neodymium(iii) coordination polymers

Abstract

Reaction of H₃TDA with Pr^III/Nd^III salts resulted in two coordination polymers, [Ln(H₂O)₄(HTDA)(H₂TDA)]·H₂O (Ln = Pr(1) and Nd(2), H₃TDA = 1H-[1,2,3]-triazole-4,5-dicarboxylic acid), crystallizing in the monoclinic P2₁/c space group with a one-dimensional zigzag chain structure. The number of ligands and water molecules coordinated to the Ln^III ions can be reduced by a hydrothermal method and the products transformed into {[Ln(TDA)(H₂O)]·2.5H₂O}_n (Ln = Pr(3) and Nd(4)), crystallizing in the trigonal P3₁21 space group with a three-dimensional chiral framework structure. The compounds were characterized by elemental analysis, IR, PXRD, circular dichroism spectra and single crystal X-ray diffraction. The variable temperature magnetic susceptibility studies indicated that there are antiferromagnetic interactions between the Ln^III ions in 1–4. Gas sorption and separation were studied as well.