Interaction of K2PdCl4 with aminoalkyldiphosphonic acids

Complexing of K2PdCl4 with 3-amino-1-hydroxypropylidene-1,1-diphosphonic acid (AHPDP) and 1-aminoethylidene-1,1-diphosphonic acid (AEDP) was studied by pH titration, spectrophotometry, and 31P NMR spectroscopy using metal to ligand mole ratios of 1: 1 and 1: 2. In equimolar complexes, AHPDP is coordinated to palladium(II) via two phosphonic oxygen atoms, whereas AEDP is coordinated via the amino nitrogen atom and a phosphonic oxygen atom. In the bisligand palladium(II) complex with AEDP, both ligand molecules are coordinated in a bidentate mode by the amino nitrogen atom and a phosphonic oxygen atom.