Investigation of the MSO_4 xH_2O (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

摘要

The reactions of methyl 2-pyridyl ketone oxime, (py)C(Me)NOH, with MSO_4 xH_2O (M = Zn, x = 7; M = Cd, x = 8/3), in the absence of an external base, have ken investigated. The synthetic study has led to the two new complexes [Zn(SO_4){(py)C(Me)NOH)(H_2O)_3] H_2O (1_ H_2O) and [Zn_2(SO_4)_2{(py)C(Me)- NOH}_4] (py)C(Me)NOH [2 _ (py)C(Me)NOH], and the coordination polymer [Cd(SO_4){(py)C(Me)NOH} (H_2O)]n_ [Cd(SO_4)[(py)C(Me)NOH}(H_2O)_2]n(3). In the three complexes the organic ligand chelates through its nitrogen atoms. The sulfate anion in 1 H_2O is monodentate; the complex molecule is the mer isomer considering the positions of the aqua ligands. The Zn~(11) centers in 2 (py)C(Me)NOH are bridged by two syn, anti η~1:η~1:μ_2 SO_4~(2-) ligands; each metal ion has the cis-cis-trans disposition of the coordinated sulfate oxygen, pyridyl nitrogen and oxime nitrogens, respectively. The molecular struc ture of 3 is unique consisting of two different linear and ladder - type chains. π-πstacking 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.