Synthesis and characterization of CpMo(CO)(3)(CH2-pC(6)H(4)-CO2CH3) and its inclusion compounds with methylated cyclodextrins. Applications in olefin epoxidation catalysis

authors	Gomes, AC; Bruno, SM; Tome, C; Valente, AA; Pillinger, M; Abrantes, M; Goncalves, IS
nationality	International
journal	JOURNAL OF ORGANOMETALLIC CHEMISTRY
author keywords	Molybdenum; Cyclopentadienyl complexes; Carbonyl ligands; Methylated cyclodextrins; Olefin epoxidation
keywords	CYCLOPENTADIENYL-MOLYBDENUM COMPLEXES; TUNGSTEN COMPLEXES; ETA(5)-CYCLOPENTADIENYL MOLYBDENUM; MESOPOROUS MATERIALS; TRICARBONYL COMPLEX; CYCLOALKYL MOIETIES; CARBONYL-COMPLEXES; BETA-CYCLODEXTRIN; BRIDGING UNITS; ANSA COMPOUNDS
abstract	The cyclopentadienyl molybdenum tricarbonyl complex CpMo(CO)(3)(CH2-pC(6)H(4)-CO2CH3) (1) (Cp = eta(5)-C5H5) and its 1:1 inclusion complexes with heptakis(2,6-di-O-methyl)-beta-cyclodextrin (1@DIMEB) and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (1@TRIMEB) were prepared and characterized by elemental and thermogravimetric analyses, powder X-ray diffraction, NMR, FT-IR and Raman spectroscopy. All three compounds were investigated as catalyst precursors for olefin epoxidation using cis-cyclooctene (Cy) as a model substrate, a reaction temperature of 55 degrees C, and different types of oxidants (tert-butylhydroperoxide in decane;(TBHPdec) or in water (TBHPaq), and aqueous hydrogen peroxide). With the aim of facilitating recycling of the homogeneous catalytic systems, different solvent mixtures were tested: biphasic liquid-liquid solvent systems [(water, glycerol, ionic liquid)-(n-hexane, alpha,alpha,alpha-trifluorotoluene (TFT), iso-butyl methyl ketone)], and in some cases no cosolvent was added. Excellent epoxide selectivity (100%) was observed for all tested catalytic systems. An example of an interesting catalytic system is that of 1@TRIMEB/TBHPaq/TFT/H2O since the catalyst can be easily separated in the form of an aqueous solution, by decantation, from the organic phase containing the reaction products and recycled. (C) 2013 Elsevier B.V. All rights reserved.
publisher	ELSEVIER SCIENCE SA
issn	0022-328X
year published	2013
volume	730
beginning page	116
ending page	122
digital object identifier (doi)	10.1016/j.jorganchem.2012.12.019
web of science category	Chemistry, Inorganic & Nuclear; Chemistry, Organic
subject category	Chemistry
unique article identifier	WOS:000318667600018