On the activity of chiral chromium salen complexes covalently bound to solid silicates for the enantioselective epoxide ring opening
Applied Catalysis A: General, 2002•Elsevier
Two series of solid catalysts in which a chiral chromium salen complex has been anchored
on aminopropyl-functionalized SiO2, ITQ-2 or MCM-41 have been prepared. In those
catalysts in which anchoring of the complex was accomplished through coordination with the
metal high enantiomeric excesses were obtained (up to 70% enantiomeric excess (ee)), but
the complex leaches to the solution on a large extent. In contrast, for those other solids in
which the complex is attached to the surface by covalent linkage to the ligand no leaching …
on aminopropyl-functionalized SiO2, ITQ-2 or MCM-41 have been prepared. In those
catalysts in which anchoring of the complex was accomplished through coordination with the
metal high enantiomeric excesses were obtained (up to 70% enantiomeric excess (ee)), but
the complex leaches to the solution on a large extent. In contrast, for those other solids in
which the complex is attached to the surface by covalent linkage to the ligand no leaching …
Two series of solid catalysts in which a chiral chromium salen complex has been anchored on aminopropyl-functionalized SiO2, ITQ-2 or MCM-41 have been prepared. In those catalysts in which anchoring of the complex was accomplished through coordination with the metal high enantiomeric excesses were obtained (up to 70% enantiomeric excess (e.e.)), but the complex leaches to the solution on a large extent. In contrast, for those other solids in which the complex is attached to the surface by covalent linkage to the ligand no leaching was observed, but the e.e. were modest (below 20%) compared to those obtained in homogeneous catalysis under comparable conditions (above 50%).
Elsevier
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