Complexes of hydroxamates VI: Binary and ternary complexes involved in the palladium(II) monohydroxamic acids—glycylglycine systems

Abstract

Binary complexes of dl-serine-, l-histidine-, glycine-, aceto-, methionine- hydroxamic acids as well as glycylglycine (Glygly) with Pd(II) have been studied in solution. Only Pd(II) complexes with methionine hydroxamic (MX) acid were successfully studied potentiometrically because the other hydroxamic acids formed instant black precipitates. The potentiometric data for Pd(II)-MX were assessed by the SUPERQUAD program. The formation constants of only two species were determined in a limited pH range. The ternary complexes of Pd(II) with Glygly and MX were also studied, in which only two species were formed. It has been possible to determine only one species for the binary interaction of Pd(II) with Glygly, which is not usually simple to obtain in the absence of MX. The differential pulse polarographic technique was applied to the binary and ternary complexes involved in the system of Pd(II)-MX-Glygly in a wider pH range than that in the potentiometric study.