Acid hydrolysis of platinum(II)-glycylglycine and platinum(II)-dipicolinate complexes. - Kinetics of ring opening and chloride release

Aquation reactions of. [Pt(digly)Cl](-) and [Pt(dipic)Cl](-) where H(2)digl y = glycylglycine and H(2)dipic = pyridine-2,6-dicarboxylic acid have been studied at [H+] = 0.1 - 1.0 mol dm(-3), I = 1.0 (NaClO4) and temperature ra nge 25 - 50 degreesC. Both the complexes show biphasic reaction traces; the first acid-dependent phase corresponds to the carboxylate ring-opening and the second acid-independent one to the release of chloride ion. The mechan isms of hydrolytic phenomenon have been discussed. The DeltaH(not equal) an d DeltaS(not equal) values for the carboxylate ring-opening have been compa red with the corresponding values for the first step ring-opening in cis-di ammine(cyclobutane-1,1-dicarboxylato)platinum(II), carboplatin.