The Ln-Cu(II)-Hpic-H₂BDC system showing interesting production variety upon different reaction conditions: hydrothermal synthesis, structures, thermostability, and magnetism

摘要

Herein, we report research regarding the Ln-Cu(II)-Hpic-H₂BDC system, where Ln, Hpic, and H₂BDC are lanthanide ions, picolinic acid, and 1,2-benzenedicarboxylic acid, respectively. Under different reaction temperatures (160°C and 170°C), the self-assembly of Gd₂O₃, CuCl₂, Hpic, and H₂BDC in water at pH = 2 adjusted by HClO₄ generates two Ln-containing coordination compounds, GdCu(pic)(PhCOO)₄ (1) and Gd(pic)(BDC)(µ-H₂O)₂(H₂O) (2) (PhCOOH = benzenecarboxylic acid). Under the same reaction conditions, if Gd₂O₃ is replaced by Pr₃O₄, then polymer Pr₄(BDC)₆(µ-H₂O)₂ (3) is obtained. The structural features are 1-D tape or 2-D irregular (6, 3) net. We also explored their phase purity by X-ray diffraction analysis and evaluated their thermostability by thermogravimetric analysis studies.