Study On Synthesis, Crystal Structures And Properties Of Co(Ⅱ), Cu(Ⅱ), Zn(Ⅱ) And Cd(Ⅱ) Complexes With Bromo-substituted Salen-type Ligands

Salen (N, N'-bis(saliylaldehyde)ethylendiamin) is based on the quadridentate Schiff bases. Salen ligands are usually synthesized by condensation of monomolecular diamine and two aldehyde molecules. Its coordination atoms normally include: two imine nitrogen atoms, the other two substituents from aldehyde, which is oxygen atoms of phenol. The characteristics of the ligand is that its distribution sites often located in the same plane, making the transition metals and ligands into the first coordination plane, leaving the two axial ligand to coordinate with auxiliary ligand. Salen ligands have well coordinated capability to the transition metal ions. Salen complexes are used as catalysts for a number of organic redox reactions, models of reaction centers of metalloenzymes, optical materials and magnetic materials etc, and also have widespread application prospect in medicine, analytical chemistry, metal corrosion and function materials. Salen-type ligands and their complexes have been extensively studied, especially have observable progress in synthesis, structures and application etc. So, preparing new Salen complexes and studying their properties and applications are of great importance to the development of coordination chemistry.In this paper, a series of diamine (1,2-bis(aminooxy)ethane, 1,3-bis(aminooxy)propane and 1,4-bis(aminooxy)butane) have been synthesized, three kinds of novel Salen-type ligands which are 4,4',6,6'-Tetrabromo-2,2'-[ethylenedioxybis(nitrilomethy-lidyne)]diphenol] (H₂L¹), 4,4',6,6'-Tetrabromo-2,2'-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol] (H₂L²), 4,4',6,6'-Tetrabromo-2,2'-[(1,4-butylene)dioxybis(nitrilomethylidyne)]diphenol] (H₂L³) have also been synthesized by the reaction of diamine and 3,5-dibromo-2-hydroxybenzaldehyde, The complexes have been synthesized by the reaction of the ligands with transition metal acetate in this article. The complexes were characterized by elementary analysis, IR spectra, ¹H-NMR, molar conductance analysis and X-ray single crystal diffraction et.al.Five single crystals of the complexes which are Cu(â…¡) acetate monohydrate complex with H₂L¹, Co(â…¡) acetate monohydrate complex with H₂L¹, Zn(â…¡) acetate monohydrate complex with H₂L¹, Cd(â…¡) acetate monohydrate complex with H₂L¹ and Zn(â…¡) acetate monohydrate cluster with H₂L⁴ have been obtained by nature evaporation method, their space structures which are determined by X-ray single crystal diffraction are as follows:Cu(â…¡) acetate monohydrate complex with H₂L¹([Cu(L¹)]), empirical formula: C₁₆H₁₀Br₄CuN₂O₄, Mr: 677.44, monoclinic, space group: P2(1)/c, cell parameters: a = 14.076(2), b = 6.9801(14), c= 19.858 (2)(?),α= 90°,β= 107.613(2)°,γ= 90°, V= 1859.6(5) (?)³, Dc = 2.420 Mg·m^-3,μ= 9.796 mm^-1, F(000) = 1284, Z= 4, R₁ = 0.0638, wR₂ = 0.1463.Co(â…¡) acetate monohydrate complex with H₂L¹([CoL¹(H₂O)₂]n), empirical formula: C₁₆H₁₄Br₄CoN₂O₆, Mr: 708.86, monoclinic, space group: P2(1)lc, cell parameters: a = 2.5168(3), b=1.02343(18), c = 0.78917(14)(?),β= 91.375(2)°, V= 2.0321(5)(?)³, D_c = 2.317 Mg·m^-3,μ( Mo Kα) = 8.747 mm^-1, F(000) = 1356, Z=4,R₁ = 0.0492, wR₂ = 0.0983.Zn(â…¡) acetate monohydrate complex with H₂L¹([ZnL¹(H₂O)₂]_n), empirical formula:1 C₁₆H₁₄Br₄N₂O₆Zn, Mr: 715.30, monoclinic, space group: P2(1)/c, cell parameters: a = 25.155(9), b = 10.200(4), c = 7.944(3)(?),β= 91.317(5)°, V= 2037.8(13)(?)³, D_c = 2.332 Mg****** m^-3,μ(Mo Kα) = 9.086 mm^-1, F(000) = 1368, Z= 4, R₁ = 0.0381, wR₂= 0.0699.Cd(â…¡) acetate monohydrate complex with H₂L¹([CdL¹(H₂O)₂]_n), empirical formula: C₁₆H₁₄Br₄CdN₂O₆, Mr: 762.33, monoclinic, space group: C2/c, cell parameters: a = 17.913(2), b = 15.303(2), c = 8.0091(14)(?),β= 95.933(3)°, V= 2183.7(6)(?)³, D_c = 2.319 Mg·m^-3,μ(Mo Kα) = 8.354 mm^-1, F(000) = 1440, Z = 4, R₁ = 0.0757, wR₂ = 0.1303.Zn(â…¡) acetate monohydrate cluster with H₂L⁴({[ZnL⁴(OAc)]₂Zn}·CH₃COCH₃), empirical formula: C₄₂H₄₂Br₄N₄O₁₄Zn₃, Mr: 1342.55, triclinic, space group: P-1, cell parameters: a = 10.1556(14), b = 11.4608(16), c = 11.9817(18)(?),α= 108.171(2)°,β= 107.662(2)°,γ=95.9960(10)°, V= 1231.7(3)(?)³, D_c = 1.810 Mg·m^-3,μ(Mo Kα) = 4.760 mm^-1, F(000) = 664, Z=1,R₁ = 0.0361, wR₂ = 0.0740.X-ray single crystal diffraction results show that there are intermolecularÏ€-Ï€stacking interactions between the nearest benzene rings in the Co(â…¡), Zn(â…¡), Cd(â…¡) complex, chain supramolecular structure was formed by hydrogen bonds andÏ€-Ï€stacking of neighboring benzene rings.The bioactivities experiments show that bromo-substituted Salen-type ligands and their complexes have remarkable antifungal effect to staph ylococcus aureus and Escherichia coli. The ntifungal effect of bromo-substituted Salen-type complexes is higher than the antifungal effect of the ligands.