Incorporation of a (cyclopentadienyl)molybdenum oxo complex in MCM-41 and its use as a catalyst for olefin epoxidation
authors Abrantes, M; Gago, S; Valente, AA; Pillinger, M; Goncalves, IS; Santos, TM; Rocha, J; Romao, CC
nationality International
journal EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
author keywords molybdenum; sandwich complexes; mesoporous materials; supported catalysts; epoxidation
keywords LIQUID-PHASE OXIDATION; MOLECULAR-SIEVES; DIOXOMOLYBDENUM(VI) COMPLEXES; MOLYBDENUM; CYCLOOCTENE; REACTIVITY; MECHANISM; SILICA
abstract The tricarbonyl complex [(eta(5)-C(5)H(4)-COOMe)Mo(CO)(3)Cl]- was prepared from the reaction of sodium (methoxycarbonyl)-cyclopentadienide, (C(5)H(4)-CO(2)Me)Na, with (Bu(4)N)[Mo(CO)(5)I]. Heating the ester with 3-(triethoxysilyl)propylamine gave the amide derivative {[eta(5)-C(5)H(4)-CONH-C(3)H(6)Si(OEt)(3)]-MO(CO)(3)Cl}. The functionalised tricarbonyl complex was immobilised in the ordered mesoporous silica MCM-41 with a loading of 13 wt.-% Mo (1.4 mmol(.)g(-1)) by carrying out a grafting reaction in dichloromethane. Powder X-ray diffraction and nitrogen adsorption-desorption analysis indicated that the structural integrity of the support was preserved during the grafting and that the channels remained accessible, despite significant reductions in surface area, pore volume and pore size. The success of the coupling reaction was confirmed by (29)Si and (13)C (CP) MAS NMR spectroscopy. A supported dioxo complex of the type [(eta(5)-C(5)H(4)R)MoO(2)Cl] was subsequently prepared by oxidative decarbonylation of the tethered tricarbonyl complex using tert-butyl hydroperoxide (TBHP). The oxidised material is an active catalyst for the liquid phase epoxidation of cyclooctene with TBHP as the oxygen source. Similar catalytic results were obtained using the tethered tricarbonyl complex directly as a pre-catalyst since fast oxidative decarbonylation occurs under the reaction conditions used. For both systems, the desired epoxide was the only product and the initial activities were about 13 mol(.)mol(Mo)(-1.)h(-1). The solid catalysts were recycled several times. Some activity was lost between the first and second runs but thereafter tended to stabilise. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
publisher WILEY-BLACKWELL
issn 1434-1948
year published 2004
issue 24
beginning page 4914
ending page 4920
digital object identifier (doi) 10.1002/ejic.200400386
web of science category Chemistry, Inorganic & Nuclear
subject category Chemistry
unique article identifier WOS:000225995200025
  ciceco authors
  impact metrics
journal analysis (jcr 2019):
journal impact factor 2.529
5 year journal impact factor 2.284
category normalized journal impact factor percentile 65.556
dimensions (citation analysis):
altmetrics (social interaction):



 


Sponsors

1suponsers_list_ciceco.jpg