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The simultaneous use of 2-pyridyl oximes (pyridine-2 amidoxime, H 2 pyaox; 2-methyl pyridyl ketoxime, Hmpko) and 1,3,5-benzenetricarboxylic acid (H 3 btc) provided access to five new compounds, namely [Zn(H 2 btc) 2 (H 2 pyaox) 2 ]•2H 2 O ( 1 •2H 2 O), [Zn(Hbtc)(H 2 pyaox) 2 ] n ( 2 ), [Cu(Hbtc)(H 2 pyaox)] n ( 3 ), [Cu(Hbtc)(HmpKo)] n ( 4 ) and [Cu 2 (Hbtc) 2 (Hmpko) 2 (H 2 O) 2 ]•4H 2 O ( 5 •4H 2 O). Among them, 3 is the first example of a metal-organic framework (MOF) containing H 2 pyaox. Its framework can be described as a 3-c uninodal net of hcb topology with the layers being parallel to the (1,0,1) plane. Furthermore, 3 is the third reported MOF based on a 2-pyridyl oxime in general. 2 and 4 are new members of a small family of coordination polymers containing an oximic ligand. 1-5 form 3D networks through strong intermolecular interactions. Dc magnetic susceptibility studies were carried out in a crystalline sample of 3 and revealed the presence of weak exchange interactions between the metal centres; the experimental data were fitted to a theoretical model with the fitting parameters being J = -0.16(1) cm -1 and g = 2.085(1). The isotropic g value was also confirmed by electronic paramagnetic resonance (EPR) spectroscopy. Reactivity studies were performed for 3 in the presence of metal ions; the reaction progress was studied and discussed for Fe(NO 3 ) 3 by the use of several characterization techniques, including single crystal X-ray crystallography and IR spectroscopy.

Ni 2 Mn (1), Ni 2 Mn 2 (2) and Mn 8 (3) species are reported from the employment of methyl-2-pyridyl oxime (in 1 and 2) and phenyl-2-pyridyl oxime (in 3). 1 and 2 are the first examples of a 3d–3d′ heterometallic cluster bearing the methyl-2-pyridyl oxime and exhibit a diamagnetic ground state. 3 contains 4 oxo-bridges and is a new member of the small family of high nuclearity Mn/(py)C(ph)NO− complexes. The initial employment of methyl 2-pyridyl ketoxime, (py)C(Me)NOH, in mixed metal Ni/Mn cluster chemistry, provided access to complexes [NiII 2 MnIII{(py)C(Me)NO} 6 ](ClO 4) (1) and [NiII 2 MnIII 2 {(py)C(Me)NO} 6 (OMe) 2 (MeOH) 2 ](ClO 4) 2 (2) that display a linear and a zig-zag metal arrangement, respectively. 1 and 2 are synthesized by reacting Ni(ClO 4) 2 ·6H 2 O, (py)C(Me)NOH, Mn(ClO 4) 2 ·6H 2 O and NaOMe in different molar ratios (2:6:1:6, 1 ; 1:3:1:3, 2) in MeOH, and they are the first examples of 3d–3d′ mixed-metal clusters bearing (py)C(Me)NOH. The employment of phenyl 2-pyridyl ketoxime, (py)C(ph)NOH, instead of (py)C(Me)NOH, provided access to the octanuclear homometallic compound [MnII 4 MnIII 4 O 4 (NO 3) 2 {(py)C(ph)NO} 8 (HCO 2) 2 (MeOH) 2 ] (3) that possesses a double-butterfly {MnII 4 MnIII 4 (μ 4 -O) 2 (μ 3 -O) 2 }12+ core. 3 joins the small family of Mn/(py)C(ph)NO− clusters. Variable-temperature, solid-state dc and ac magnetic susceptibility studies were carried out on 1 and 2 and revealed the presence of antiferromagnetic exchange interactions between the metal ions (J Mn–Ni = −6.34 ± 0.14 cm−1 in 1; J Mn–Ni = −4.57 ± 0.08 cm−1, J Mn–Mn = −12.72 ± 0.12 in 2) and a diamagnetic ground state for both compounds. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The first use of biacetylmonoxime picolinoylhydrazone in lanthanide(III) chemistry has provided access to a structurally interesting dinuclear praseodymium(III) complex. The ligand undergoes an impressive dysprosium(III)-assisted hydrolysis of its hydrazone and oxime functionalities to give a polydentate ligand containing two picolinoyl and two hydrazone moieties. [ABSTRACT FROM AUTHOR]