Isomeric Forms As Biological Probes

Although outside the main thrust of the book, attention should be drawn to the important use that octahedral complexes are receiving as molecular probes. Metal complexes can sometimes recognize specific sites on biological material. The array of isomeric forms possible with some metal complexes (previous section) adds a dimension to their use as probes. 

The racemic Fe(III) complex containing a hexadentate ligand, Fe(5-Br-ehpg) , can exist in racemic RR and SS) and meso (RS) forms (Structures 7a and 7b) which have different solubilities in methanol. 

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