Complexing properties of 2-pyridylphoshonate and 2-pyridylsulfonate ligands for Zn2+ and Ag+ central atoms

The Zn2+/Ag+-pypo and pysu (pypo = 2-pyridylphosphonate, pysu = 2-pyridylsulfonate) complexes speciation in aqueous solution at I = 0.1 M (KNO3) and 25 degrees C is described in detail under our experimental synthetic conditions. Protonation and stability constants were determined, and distribution diagrams show protonated and deprotonated complexes formation in the case of Zn2+/Ag+ pypo/pysu binary system, respectively. Moreover, the new complex, {[Zn(H(2)pypo)(2)(H2O)(2)]}(n)(ClO4)(2n)center dot 2nH(2)O, was isolated and its spectral and structural properties were determined. An unusual pypo bidentate coordination mode is described and compared with published ones.