One Trinuclear Copper(II) Polymer Based on Pyridine-2,4,6-Tricarboxylic Acid: Synthesis, Structure, and Magnetic Analysis

Resumo

The reaction of CuCl₂ · 2H₂O with pyridine-2,4,6-tricarboxylic acid (H₃Pyta) in ethanol and water under hydrothermal synthesis conditions leads to the formation of a trinuclear copper polymer {[Cu₃(Pyta^3–)₂(H₂O)₈] · 4H₂O}n (I) (C₁₆H₂₈N₂O₂₄Cu₃, Mr = 823.05, ρ_calcd = 1.955 g cm^–3). The polymer was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction (СIF file CCDC no. 1525203). The result showed that I belongs to the monoclinic system, P2₁/c space group. TGA curve shows that polymer I first removes water molecules, and then the ligand split for polymer I, and the remained residue is CuO. The magnetic measurement reveals the pyridine-2,4,6-tricarboxylic acid as bridge ligand can mediate the antiferromagnetic coupling interaction between magnetic centers.