Synthesis and structural characterizations of tris(hydroxymethyl)aminomethane complexes with group IIA metals

Abstract

Herein, this article aimed to investigate the tendency of tris(hydroxymethyl) aminomethane (THAM) to form stable complexes with group IIA metals. Four new colorless solid complexes of group IIA metals [Ba(II), Ca(II), Sr(II) and Mg(II)] with THAM were prepared and well characterized. The chemical reactions between group IIA metals and THAM were conducted by stoichiometry of 2:1 (Ligand: Metal ion) at 65 °C and pH of ~ 8.5. Under these conditions, the THAM molecule (C4H11NO3) was deprotonated and converted to the (C4H10NO3-; L-) chelate with the metal ions. The structures of these complexes were suggested by UV-visible, IR, Raman and 1H NMR spectroscopies and other physicochemical and analytical methods (elemental analysis, thermogravimetry, and SEM). The results shows that the general composition of the complexes obtained with Ba(II), Ca(II), Sr(II) and Mg(II) ions are [BaL2(H2O)2], [CaL2(H2O)2]·2H2O, [SrL2(H2O)2], and [MgL2(H2O)2]·4H2O, respectively, and in all complexes, the geometry was octahedral.