Catalysis Today, Vol.117, No.1-3, 141-147, 2006
Catalyst design for selective oxidation with molecular oxygen by metal-complex attachment
We have prepared novel metal-ensemble catalysts by chemical attachment of metal-complex precursors, N-interstitial Re-10 cluster supported on HZSM-5 and chiral self-dimerized V-dimer on SiO2, which are active and highly selective for selective oxidation with molecular oxygen. The Re-10(N)(2)/HZSM-5 catalyst exhibited 87.7% (steady-state reaction) and 93.9% (pulse reaction) selectivity for direct phenol synthesis from benzene with molecular oxygen. The structures of active metal species were characterized by EXAFS, TPD and DFT calculations. The chiral self-dimerized V-dimer catalyst was found to be the first heterogeneous catalyst for the asymmetric oxidative coupling of 2-naphthol with molecular oxygen, which exhibited 100% selectivity and 90% enantioselectivity. (C) 2006 Elsevier B.V. All rights reserved.