Nucleophilic Attack by OH2 or OH–: A Detailed Investigation on pH-Dependent Performance of a Ru Catalyst

The considerable rate enhancements along with the increase in pH values may be due to the direct involvement of hydroxide anion in attacking electrophilic [RuV(tda)­(py)2O]+ (1; tda = [2,2′:6′,2″-terpyridine]-6,6″-dicarboxylate, py = pyridine). The enhanced reaction rate is well in agreement with the descending activation barriers in our calculation. The addition of four extra water molecules in the geometry optimization plays a key role in stabilizing hydroxide anion as well as building a reasonable hydrogen-bonding network, and three of these molecules are required to stabilize the OH as an anion instead of a radical.