On Thallium(I) Chelates of 1,2-Cyclohexanediamine-N,N,N′,N′-tetraacetic Acid and Diethylenetriaminepentaacetic Acid

The stability constants of the complexes mentioned in the title obtained by us by potentiometric pH measurements are compared with those of Kodama et al. Because sodium ion forms quite a stable 1,2-cyclohexanediamine-N,N,N′,N′-tetraacetate (CyDTA) complex, the discrepancy of the values can be explained. Further new calculations confirm the formation of protonated chelate with CyDTA but in a very limited pH range.