Ligand exchange mechanism for

Stability of Metal Complex. - The stability of the metal complex towards ligand exchange reaction plays a major role in determining the mechanism by which the metal complex becomes anchored to the surface. The ligand exchange mechanism for anchoring the metal complex to the surface proceeds as... 

Much experimental evidence has been adduced in support of the ligand exchange mechanism for oxyanion adsorption. The principal lines of reasoning that lead to this mechanism can be summarized as follows. 

Fig. 1.14. Reaction diagram for the dissociative ligand exchange mechanism for d-l cations.

The most widely used approach for the separation of enantiomers by TLC is based on a ligand exchange mechanism using commercially available reversed-phase plates impregnated with a solution of copper acetate and (2S,4R,2 RS)-4-hydroxy-l-(2-hydroxydodecyl)proline in optimized amounts. Figure 7.9 (10,97,98,107-109). Enantiomers are separated based on the differences in the stability of the diastereomeric complexes formed between the sample, copper, and the proline selector. As a consequence, a prime requirement for separation is that the seumple must be able to form complexes with copper. Such compounds include... 

In microbial iron assimilation, one mechanism for the release of iron from siderophores is the enzymatic reduction to the Fe state. Siderophore stability constants are much lower for Fe +, which has a lower charge-to-radius ratio. Moreover, ligand exchange reactions for the high-spin Fe ion are much faster than for the Fe ion. Stability constants of ferrous siderophores are experimentally difficult to obtain. Limiting pH-independent redox potentials can be utilized, however, to describe the electrochemical and chemical equilibria between fidly coordinated Fe + and Fe +-siderophore complexes and the uncomplexed Fe(H20)6 + and Fe(H20)e +, respectively, in a simple model as described in equation (5) ... 

To confirm fhat a dissociative ligand exchange mechanism is in operation, the kinetics of fhe rapid reaction of fhese complexes wifh efhyl vinyl ether was studied by NMR and UV/VIS spectroscopies. The results were in complete agreement with a dissociative hgand exchange mechanism for aU complexes in this series, with the possible exception of fhe diiodo derivatives [101]. 

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