Inclusion Complex Formation by Transition-Metal Complexes Containing a Void in Proximity to a Site That Can Be Made Catalytically Active

Carbon-13 chemical shift studies show that, in aqueous solutions, a variety of alcohols and phenols enter the hydrophobic void of a new family of host molecules. Each carbon atom of the host shows a distinctive chemical shift change as the concentration of inclusion complex is increased by incrementally increasing the guest concentration. This and the fact that all of the chemical shift changes reach saturation simultaneously establish the proposed guest-host association. The signs and magnitudes of the total chemical shift changes at saturation of the equilibrium can be accounted for semiquantitatively with a model in which solvent water is displaced from the cavity by the guest. The significance of inclusion complex formation in these systems to the development of a new class of oxidation catalysts is discussed.