Tailoring the Windows Sizes to Control the Local Concentration and Activity of salen(Co) Catalysts in Plugged Nanochannels of SBA-15

Organometallic complexes with excellent activity and selectivity have found many applications in homogeneous catalysis for the transformation of organic molecules. The use of chiral metal complexes in particular has facilitated the economically viable synthesis of enantiopure organic compounds with a global market of 5.3 billion US$ in 2011 with an annual growth rate of 6.5%.[1] Among these, chiral (salen)metal complexes catalyze many asymmetric transformations of, for example, the hydrolysis of terminal epoxides through hydrolytic kinetic resolution (HKR) into single enantiomers.[2–5] The reaction kinetics are second order in catalyst concentration through the close proximity of two metal complexes in the activation of the substrates, which resembles the active site of an enzyme (Supporting Information, Scheme S1).