beta-cyclodextrin and permethylated beta-cyclodextrin inclusion compounds of a cyclopentadienyl molybdenum tricarbonyl complex and their use as cyclooctene epoxidation catalyst precursors
authors Braga, SS; Gago, S; Seixas, JD; Valente, AA; Pillinger, M; Santos, TM; Goncalves, IS; Romao, CC
nationality International
journal INORGANICA CHIMICA ACTA
author keywords cyclodextrins; inclusion compounds; sandwich complexes; molybdenum; olefin epoxidation; oxidative decarbonylation
keywords METAL-CARBONYL-COMPLEXES; HALF-SANDWICH COMPLEXES; C-13 CHEMICAL-SHIFTS; OLEFIN EPOXIDATION; CRYSTAL-STRUCTURE; SOLID-STATE; 2ND-SPHERE COORDINATION; MESOPOROUS MATERIALS; ENCAPSULATION; CPMO(CO)(3)CL
abstract The complex CpMo(CO)(3)CH2CONH2 was immobilized in plain P-cyclodextrin (P-CD) and permethylated beta-CD (TRIMEB), and the resultant inclusion compounds were characterized in the solid-state by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), C-13{H-1} CP/MAS NMR spectroscopy and FTIR spectroscopy. The non-included tricarbonyl complex can be used directly as a precursor to an active (TOF ca. 250 mol mol(Mo)(-1), h(-1)) and selective homogeneous catalyst for the epoxidation of cyclooctene. Under the reaction conditions, rapid oxidative decarbonylation of the complex by the oxidant tert-butyl hydroperoxide (t-BuOOH) takes place to give the active Mo-VI catalyst. The cyclodextrin inclusion compounds were also tested as pre-catalysts for homogeneous or heterogeneous cyclooctene epoxidation. With no additional co-solvent, the TRIMEB inclusion compound was soluble under the reaction conditions and gave rise to catalytic activity similar to that observed for the pure non-included complex. The P-CD adduct was insoluble and exhibited comparatively lower activity, but could be recycled without loss of activity. The catalytic behavior of the two inclusion compounds was also tested in the presence of the ethanol, n-hexane and 1,2-dichloroethane solvents, as well as in a biphasic system comprising water and n-hexane. (c) 2006 Elseiver B.V. All rights reserved.
publisher ELSEVIER SCIENCE SA
issn 0020-1693
year published 2006
volume 359
issue 15
beginning page 4757
ending page 4764
digital object identifier (doi) 10.1016/j.ica.2006.03.017
web of science category Chemistry, Inorganic & Nuclear
subject category Chemistry
unique article identifier WOS:000243018300007
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journal impact factor 2.304
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