Molecular structures of some bivalent metal complexes of 1-(4-acetylphenyl)imidazole and co-ligands

Abstract

A series of bivalent metal complexes having compositions [Co(L)2Cl2] (1), [Zn(L)2Cl2] (2), [Co(L)2(H2O)4](NO3)2·2H2O (3), [Zn(L)2(H2O)4](NO3)2·2H2O (4), [Co(L)2(OAc)2(H2O)]·3H2O (5), [Mn(L)2(OAc)2(H2O)]·3H2O (6) [Co(L)4(NCS)2] (7), {[Co(L)2(Fum)(H2O)2]·2H2O}n (8) and {[Mn(L)2(Fum)]}n (9) were synthesized using L {L = 1-(4-acetylphenyl)imidazole} and respective co-ligands. The mononuclear sets 1–2, 3–4 and 5–6 are isomorphous and isostructural in nature. Complex 7 is a mononuclear complex, 8 is a 1D coordination polymer and 9 is a 2D-coordination polymer. All the compounds were structurally characterized using IR spectroscopy, thermogravimetric analyses, powder X-ray and single crystal X-ray diffraction studies. In general, coordinated/lattice water molecules are found to be involved in OH⋯O hydrogen bonding and counter ions, in other weak interactions like CH⋯S, CH⋯Cl and CH⋯O. The aromatic ring of L also is involved in CH⋯π and π⋯π stacking interactions. In 3 and 4, hydrogen bonding interactions between coordinated water molecules, lattice water and nitrate ion contain cyclic hydrogen-bonded architectures. In 5 and 6, acetyl group present in L act as hydrogen bond acceptor through O⋯HO interaction. In 8 and 9 Fum coordinate to metal center in μ-η1:η1 bidentate and μ4-η1:η1:η1:η1 tetradentate fashions resulting in formation of 1D and 2D coordination polymers, respectively.