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‘ 2 Mo(OH)(H 2 O) + ( 1 ) (Cp‘ = η 5 -C 5 H 4 CH 3 ) and the stoichiometric oxidation of CO to CO 2 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 ∼7, ∼80 °C). 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 (Δ H ⧧ = 5.9 ± 0.7 kcal/mol and Δ S ⧧ = −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.