Aqueous phase organometallic catalysis using (MeCp)2Mo(OH)(H2O)+.: Intramolecular attack of hydroxide on organic substrates

The hydrolysis of esters and difunctional ethers catalyzed by Cp'Mo-2(OH)(H2O)(+) (1) (Cp' = eta(5)-C5H4CH3) and the stoichiometric oxidation of CO to CO2 in the presence of 1 are described. These reactions, combined with the previously reported nitrile hydrations and phosphate esters hydrolyses catalyzed by 1, demonstrate that 1 is an effective homogeneous catalyst for hydration, hydrolysis, and oxidation reactions in aqueous solution under mild conditions (pH similar to7, similar to80 degreesC). Each reaction is proposed to proceed by intramolecular attack of the hydroxide ligand on a bound substrate. The intramolecular nature of the reaction is supported by the ester hydrolysis activation parameters (DeltaH(double dagger) = 5.9 +/- 0.7 kcal/mol and DeltaS(double dagger) = -48 +/- 9 eu), the lack of H/D exchange, and the significant increase (10(6)-10(8)) in the rate of hydrolysis over uncatalyzed hydrolysis.