The employment of di-2-pyridyl ketone, (py)CO, in heterometallic Mn/4f and homometallic Mn cluster chemistry has yielded six MnLn and two MnMn structurally related clusters, namely, [MnLnO{(py)CO}(NO)(RCO)(HO)](NO) (Ln = Gd, 1, 5; Dy, 2; Tb, 3; R = Et, 1-3; Me, 5), [MnDyO{(py)CO}(NO)(EtCO)(HO)(MeOH)]·0.7MeOH·0.8HO (4·0.7MeOH·0.8HO), [MnGdO{(py)CO}(NO)(CHClCO)(MeOH)(py)]·2MeOH (6·2MeOH), [MnO{(py)CO}(py)(HO)](ClO)·4HO (7·4HO), and [MnO{(py)CO}(NO)(py)] (8), where (py)CO is the dianion of the gem-diol derivative of (py)CO. The compounds possess a new type of cross-shaped structural core, which in the case of 1-6 is essentially planar, whereas in 7 and 8 it deviates from planarity. Clusters 1-6 are rare examples of Mn/4f species bearing (py)CO or its derivatives, despite the fact that this ligand has been well-studied and proven a rich source of more than 200 metal compounds so far. Variable-temperature, solid-state direct-current and alternating-current magnetization studies were performed on complexes 1-5, 7, and 8 revealing that the dominant exchange interactions between the metal ions are antiferromagnetic and indicating ground-state spin values of S = 5 (for 1), 6 (for 5), and 2 (for 7 and 8).

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 FeIII 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.

Three new nanosized clusters and single molecule magnets ([Mn24] and [Mn23]) with uncommon supertetrahedral T4 – like Mn/O cores prepared from the combination of pdH2 with (py)2CO in Mn cluster chemistry are reported.

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