Anions as stabilizing ligands for Ni(III)(cyclam) in aqueous solutions

Several new anions were shown to be good stabilizing ligands for Ni(III)L(H2O)23+, (L = 1,4,8,11-tetraazacyclotetradecane, cyclam) in aqueous solutions. Mo7O246-, phosphonates, phosphates, including the biological relevant ATP were shown to have the highest binding constants to the tervalent nickel ion. The results suggest that the charge density of the anion at the binding site and the basicity of the anion are the main factors affecting the binding constant to the central Ni(III) cation.

The stability constants K = [Ni(III)LX23-2n]/[Ni(III)L(H2O)23+][Xn-]2 increase with the n and with the basicity of Xn−.Figure optionsDownload as PowerPoint slide