Reactions of Nickel (II) Sulfate Hexahydrate with Methyl(2-pyridyl)ketone Oxime: Two Mononuclear Sulfato Complexes Containing the Neutral Ligand

The reactions of methyl(2-pyridyl)ketone oxime, (py)C(Me)NOH, with nickel(II) sulfate hexahydrate, in the absence of an external base, have been investigated. The reaction between equimolar quantities of NiSO4 ·6 H2O and (py)C(Me)NOH in H2O leads to the mononuclear complex [Ni(SO4){(py)C(Me)NOH}(H2O)3] ·H2O (1 ·H2O), while an excess of the organic ligand affords the 1 : 2 compound [Ni(SO4){(py)C(Me)NOH}2(H2O)] ·H2O (2 ·H2O). The structures of both compounds have been determined by single crystal X-ray diffraction. In both complexes the organic ligand chelates through its nitrogen atoms and the sulfate anion acts as a monodentate ligand. The thermal decomposition of complexes 1 ·H2O and 2 ·H2O has been studied. The IR data are discussed in terms of the nature of bonding and the structures of the two complexes.