Complexes of platinum(II) and palladium(II) with aminomethylphosphonic acid and glycylaminomethylphosphonic acid

Abstract

The complexing properties of aminomethylphosphonic acid, Gly-(P), and glycylaminomethylphosphonic acid, Gly-Gly-(P), with Pt ^II and Pd ^II were investigated pH-metrically at 25 °C and at an ionic strength of 0.1 mol dm ^-3 (KNO ₃ ) using ‘out of cell’ titrations. The stability constants calculated indicate formation of complexes with a metal∶ligand molar ratio of 1∶1 and 1∶2. The species and their distribution determined pH-metrically were confirmed by ³¹ P and ¹ H NMR titrations. Comparison of our results for Gly-(P) and Gly-Gly-(P) with those for glycine and glycylglycine and other common dipeptides shows that the complexing properties of Pd ^II and Pt ^II towards both types are very similar.