Investigation of the MSO4 · xH2O (M = Zn, x = 7; M = Cd, x = 8/3)/methyl 2-pyridyl ketone oxime reaction system: A novel Cd(II) coordination polymer versus mononuclear and dinuclear Zn(II) complexes

The reactions of methyl 2-pyridyl ketone oxime, (py)C(Me)NOH, with MSO4 · x H2O (M = Zn, x = 7; M = Cd, x = 8/3), in the absence of an external base, have been investigated. The synthetic study has led to the two new complexes [Zn(SO4){(py)C(Me)NOH}(H2O)3] · H2O (1 · H2O) and [Zn2(SO4)2{(py)C(Me)NOH}4] · (py)C(Me)NOH [2 · (py)C(Me)NOH], and the coordination polymer [Cd(SO4){(py)C(Me)NOH}(H2O)]n · [Cd(SO4){(py)C(Me)NOH}(H2O)2]n (3). In the three complexes the organic ligand chelates through its nitrogen atoms. The sulfate anion in 1 · H2O is monodentate; the complex molecule is the mer isomer considering the positions of the aqua ligands. The ZnII centers in 2 · (py)C(Me)NOH are bridged by two syn, anti η1:η1:μ2View the MathML sourceSO42- ligands; each metal ion has the cis–cis–trans disposition of the coordinated sulfate oxygen, pyridyl nitrogen and oxime nitrogens, respectively. The molecular structure of 3 is unique consisting of two different linear and ladder – type chains. π–π stacking interactions and/or hydrogen bonds lead to the formation of interesting supramolecular architectures in the three complexes. The thermal decomposition of complex 3 has been studied. Characteristic vibrational (IR, Raman) bands are discussed in terms of the nature of bonding and the structures of the three complexes.