Synthesis, Structure, and Catalytic Performance in Cyclooctene Epoxidation of a Molybdenum Oxide/Bipyridine Hybrid Material: {[MoO3(bipy)][MoO3(H2O)]}n
authors Abrantes, M; Amarante, TR; Antunes, MM; Gago, S; Paz, FAA; Margiolaki, I; Rodrigues, AE; Pillinger, M; Valente, AA; Goncalves, IS
nationality International
journal INORGANIC CHEMISTRY
keywords TERT-BUTYL HYDROPEROXIDE; BOND-VALENCE PARAMETERS; DIFFRACTION BEAM LINE; CRYSTAL-STRUCTURES; OLEFIN EPOXIDATION; DIOXOMOLYBDENUM(VI) COMPLEXES; HYDROTHERMAL SYNTHESIS; DICHOTOMY METHOD; LEWIS-BASE; OXIDES
abstract The reaction of [MoO2Cl2(bipy)] (1) (bipy = 2,2'-bipyridine) with water in a Teflon-lined stainless steel autoclave (100 degrees C, 19 h), in an open reflux system with oil bath heating (12 h) or in a microwave synthesis system (120 degrees C, 4 h), gave the molybdenum oxide/bipyridine hybrid material {[MoO3(bipy)][MoO3(H2O)]}(n) (2) as a microcrystalline powder in yields of 72-92%. The crystal structure of 2 determined from synchrotron X-ray powder diffraction data is composed of two distinct neutral one-dimensional polymers: an organic-inorganic polymer, [MoO3(bipy)](n), and a purely inorganic chain, [MoO3(H2O)](n), which are interconnected by O-H center dot center dot center dot O hydrogen bonding interactions. Compound 2 is a moderately active, stable, and selective catalyst for the epoxidation of cis-cyclooctene at 55 degrees C with tert-butylhydroperoxide (tBuOOH, 5.5 M in decane or 70% aqueous) as the oxidant. Biphasic solid-liquid or triphasic solid-organic-aqueous mixtures are formed, and 1,2-epoxycyclooctane is the only reaction product. When n-hexane is employed as a cosolvent and tBuOOH(decane) is the oxidant, the catalytic reaction is heterogeneous in nature, and the solid catalyst can be recycled and reused without a loss of activity. For comparison, the catalytic performance of the precursor 1 was also investigated. The IR spectra of solids recovered after catalysis indicate that 1 transforms into the organic-inorganic polymer [MoO3(bipy)] when the oxidant is tBuOOH(decane) and compound 2 when the oxidant is 70% aqueous tBuOOH.
publisher AMER CHEMICAL SOC
issn 0020-1669
year published 2010
volume 49
issue 15
beginning page 6865
ending page 6873
digital object identifier (doi) 10.1021/ic100479a
web of science category Chemistry, Inorganic & Nuclear
subject category Chemistry
unique article identifier WOS:000280365300022

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