Effects on Solubility and Catalyst Separation

Since all the complexes under discussion are ionic, it is not surprising to find that most are soluble only in polar solvents. This can be very useful in separating the desired product from the spent catalyst. For example. Professor Bill Suggs has shown that our catalyst, [Ir(cod)PCy3(py)]PF6, is useful in certain steroid reductions. Here, the reaction solvent is CH2CI2. To isolate the steroidal product, the solvent is removed and the residue extracted with hexane. The extract contains only the steroid and not the insoluble catalyst. 

An ion exchange resin has been used to immobilize a cationic catalyst. Although in this case the cationic center was formed by 

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