Spectroscopic studies on the complexation of some transition metals with Chloramphenicol drug

Complexes of Chloramphenicol (CHL, H2L) with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) were obtained in methanolic solution at similar to pH 7.00-7.50 using NaOH. Elemental analyses are consistent with the formulas: Na-2[M(CHL)(2)(H2O)(2)]center dot nH(2)O where (M = Mn(II), Co(II) and Ni(II), and n = 2, 4 and 6), Na-2[M(CHL)(2)]center dot nH(2)O where (M = Zn(II), Cd(II) and Hg(II), and n = 0, 1, and 2), and [Cu(CHL)(2)]center dot 4H(2)O. The IR spectra of the prepared complexes indicate that, the metal coordinated via both hydroxyl groups, while the Cu(II) complex is coordinated through one of the hydroxyl groups and carbonyl of the amide group. Except for Cu2+ all the metal ions form six membered ring complexes with Chloramphenicol. These complexes have been characterized by elemental analysis, magnetic susceptibility, molar conductance, infrared, electronic spectral and thermogravimetric (TGA/DTG) measurements. The CHL ligand as well as their complexes have been checked against some kinds of bacteria and fungi and give a significant effect. The kinetic thermodynamic parameters such as: E*, Delta H*, Delta S* and Delta G* are estimated using Coats and Redfern as well as Horowitz-Metzger equations. (C) 2008 Elsevier B.V. All rights reserved.