Abstract
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.