Ethylenediamine, ligand exchange reactions

Murmann (18) has investigated the reaction of some amineoximatonickel (II) complexes with EDTA as well as isotopic ligand exchange with the amineoximes. These systems are rather complicated, but the replacement rate of the chelate ligand does show the typical two term rate law (22). It was also observed that the reaction rate is catalyzed by the addition of other substances such as ammonia, ethylenediamine and oxalate ion. 

The competition between Cu and Ca for ethylenediamine tetraacetic acid (EDTA) and humic acid is an example of a double-exchange reaction (Table 9.4 Hering and Morel, 1989). If Cu is added to a solution of Ca EDTA and Ca humate, it replaces Ca in the weakly bound Ca humate initially, but, as time progresses, it is able to exchange with EDTA-bound Ca by either a ligand- or... 

In acid media, the complexes undergo rapid hydrolysis to yield free diamines, as shown for [Tc02(en)2] + [43]. The stability of the complexes is between that of O-coordinated and S-coordinated complexes, as shown in the reaction sequence of Tc(V) gluconate with pyridine, ethylenediamine or o-phenylenediamine to give the cationic N-coordinated species these, in turn, are able to exchange the nitrogen ligands by dithiols, such as DMSA [40]. 

---