Formation of N-oxido copper ethylenediaminetetraacetate and propanediaminetetraacetate and their selective degradation to iminodiacetate and propanediaminediacetate.

N-Oxido copper(ii) ethylenediaminetetraacetate Na4n[Cu2(edtaO2)2(H2O)4]n·13nH2O (2) (H4edta = ethylenediaminetetraacetic acid, C10H16O8N2) and N-oxido copper(ii) 1,3-propanediaminetetraacetate Na5nOn[Cu2(HpdtaO2)2Cl]n·12.5nH2O (4) (H4pdta = 1,3-propanediaminetetraacetic acid, C11H18O8N2) were obtained from the reactions of copper(ii) edta and pdta respectively with hydrogen peroxide. The copper ions in 2 and 4 are hexa-coordinated by edtaO2 or pdtaO2 ligands, forming 1D chain structures. Further reactions of 2 and 4 at lower pH values result in the isolation of copper(ii) iminodiacetate K[Cu(ida)(H2O)2Cl] (3) (H2ida = iminodiacetate acid, C4H7O4N) and copper(ii) propanediaminediacetate [Cu2(pdda)2]n·nH2O (5) (H2pdda = propanediaminediacetic acid, C7H10O4N2), respectively, which show the selective degradation of ethylenediaminetetraacetate and propanediaminetetraacetate.