From 1D Coordination Polymers to Metal Organic Frameworks by the Use of 2-Pyridyl Oximes

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 (H(2)pyaox) and 2-methyl pyridyl ketoxime (Hmpko) in combination with 1,2,4,5-benzene tetracarboxylic acid (pyromellitic acid), H(4)pma, provided access to nine new compounds whose structures and properties are discussed in detail. Among them, [Zn(2)(pma)(H(2)pyaox)(2)(H(2)O)(2)](n) (3) and [Cu(4)(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. [Zn(2)(pma)(H(2)pyaox)(2)](n) (2), [Cu(2)(pma)(H(2)pyaox)(2)(DMF)(2)](n) (6), and [Cu(2)(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 Fe(3+) ions, which is a very desirable property for the development of magnetism-based sensors.