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Tuning CuII coordination polymers derived from a bis(pyrazolecarboxylate) ligand by solvothermal C-H bond activation: Synthesis, structures, catalysis, and magnetic properties
Published in Wiley-VCH Verlag
Volume: 2014
Issue: 34
Pages: 5874 - 5884
A new bis(pyrazolecarboxylate) ligand, 1,3-phenylenebis(1H-pyrazole-5-carboxylic acid) (H2PBPC) has been synthesized to study the structure and intriguing properties of the resultant coordination polymers synthesized under solvothermal conditions. The reaction of H2PBPC with Cu(ClO4)2 in the presence of NaOH at two different temperatures (80 and 120 °C) resulted in two coordination polymers, namely, [{Cu2Na(H2OPBPC)}]∞ (1) and [{Cu4Na2(H2OPBPC)2}]∞ (2), which display 2D corrugated sheet and 3D staircase architectures, respectively; in these structures, the aromatic C-H bond flanked by the pyrazolecarboxylate moieties was oxidized to form a C-O bond. When 2,2′-bipyridine (2,2′-bpy) was used instead of NaOH, [{Cu2(2,2′-bpy)2(H2PBPC)}(H2O)]∞ (3) formed, and such C-H bond activation was not observed. Interestingly, one of the coordination polymers, namely, 1, displayed catecholase and phosphatase activity. Variable-temperature magnetic susceptibility data in the range 2-300 K showed that there is antiferromagnetic coupling between the metal centers of 1 and 2 that is mediated through the phenoxo and pyrazole bridges, whereas 3 revealed dominant ferromagnetic interactions between the bis(pyrazolato)-bridged CuII centers owing to its very unusual Cu-N-N-Cu torsion angles of 75.28 and 69.52°. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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JournalData powered by TypesetEuropean Journal of Inorganic Chemistry
PublisherData powered by TypesetWiley-VCH Verlag