Redox properties ligand bonding

A further example of the change in redox properties due to the effective charge transfer from the metal to a ji-bonding ligand will be given in the following section. 

The equatorial ligands, which influence the redox properties of the central metal ion, depending on their a-donor character. Thus structure and identity of the equatorial ligands affect the properties of the transient complex, i.e., the stability of the M-C bond. 

When the 7r-bonding ligand contains a sulfur or phosphorus atom, the redox properties of the corresponding complexes are much more like the corresponding metallocene. Thus the Fen(B10H10S)22- and Fen(B9H9 CHP)22 ions are more stable than the Fe(III) species. 

Metal-based pharmaceuticals offer unprecedented versatility in medicinal chemistry because of the different building blocks from which they can be constructed, the variety of available interactions (H-bond, 7t-stacking, coordinative bond, spatial recognition), the combination of rigidity around the metal and flexibility in the ligands, the kinetics of ligand substitution when coordinative bonds with biomolecules are formed and because of their redox properties. 

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