The synthesis and characterization of coordination polymers and metal-organic frameworks (MOFs) has attracted a significant interest over the last decades due to their fascinating physical properties, as well as their use in a wide range of technological, environmental, and biomedical applications. The initial use of 2-pyridyl oximic ligands such as pyridine-2 amidoxime (H₂pyaox) and 2-methyl pyridyl ketoxime (Hmpko) in combination with 1,2,4,5-benzene tetracarboxylic acid (pyromellitic acid), H₄pma, provided access to nine new compounds whose structures and properties are discussed in detail. Among them, [Zn₂(pma)(H₂pyaox)₂(H₂O)₂]_n (3) and [Cu₄(OH)₂(pma)(mpko)₂]_n (9) are the first MOFs based on a 2-pyridyl oxime with 9 possessing a novel 3,4,5,8-c net topology. [Zn₂(pma)(H₂pyaox)₂]_n (2), [Cu₂(pma)(H₂pyaox)₂(DMF)₂]_n (6), and [Cu₂(pma)(Hmpko)₂(DMF)₂]_n (8) join a small family of coordination polymers containing an oximic ligand. 9 exhibits selectivity for Fe^III ions adsorption, as was demonstrated by a variety of techniques including UV-vis, EDX, and magnetism. DC magnetic susceptibility studies in 9 revealed the presence of strong antiferromagnetic interactions between the metal centers, which lead to a diamagnetic ground state; it was also found that the magnetic properties of 9 are affected by the amount of the encapsulated Fe³⁺ ions, which is a very desirable property for the development of magnetism-based sensors.

Auban Gérard

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