Heterogeneous Catalytic Oxidation by MFU‐1: A Cobalt(II)‐Containing Metal–Organic Framework

Tonigold, Markus; Lu, Yaojie; Bredenkötter, Björn; Rieger, Bernhard; Bahnmüller, Stefan; Hitzbleck, Julia; Langstein, Gerhard; Volkmer, Dirk

doi:10.1002/anie.200901241

Cited by 194 publications

(122 citation statements)

References 47 publications

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“…The formation of the tert-butyl-2-cyclohexenyl-1-peroxide 4 must be ascribed to a radical pathways between the substrate and the oxidant TBHP and was recently further investigated for unsaturated Co-MOFs. 14,46 Freely diffusing peroxy radicals can be generated by a variety of mechanisms in which the oxidation state of vanadium changes. It is well known that radicals are better stabilized in water than in decane and thus such radical pathways are more prominent present in such polarisable media.…”

Section: Reaction Kinetics: Direct Versus Radical Pathwaymentioning

confidence: 99%

“…Moreover, unlike traditional immobilized catalysts 9,10,11 , the active catalytic sites in MOFs are well protected by the coordination bonds which prevents leaching to a higher extent. Although the research in this field is relatively new, MOFs have been studied as catalysts in hydrogenation and oxidation reactions 12,13,14,15,16,17,18 enantioselective reactions 19,20,21 , photocatalysis 22 , carbonyl cyanosilylation 23,24,25 , hydrodesulfurization 26 and esterification 27 .…”

Section: Introductionmentioning

confidence: 99%

“…They carried out a preliminary catalytic investigation on this modified MOF structure for the oxidation of cyclohexene with tert-butylhydroperoxide (TBHP) as the oxidant. Volkmer and co-workers 14 have designed and synthesized a MOF containing unsaturated cobalt sites, namely MFU-1. MFU-1 showed a cyclohexene conversion of 22.5% after 22 h of reaction (theoretically maximum 50% conversion), with tert-butyl-2-cyclohexenyl-1-peroxide as the main product (66% selectivity).…”

Section: Introductionmentioning

confidence: 99%

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The coordinatively saturated vanadium MIL-47 as a low leaching heterogeneous catalyst in the oxidation of cyclohexene

Leus

Vandichel

Liu

et al. 2012

Journal of Catalysis

101

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A Metal Organic Framework, containing coordinatively saturated V +IV sites linked together by terephthalic linkers (V-MIL-47) is evaluated as a catalyst in the epoxidation of cyclohexene. Different solvents and conditions are tested and compared. If the oxidant TBHP is dissolved in water, a significant leaching of V-species into the solution is observed and also radical pathways are 2 prominently operative leading to the formation of an adduct between the peroxide and cyclohexene. If however the oxidant is dissolved in decane, leaching is negligible and the structural integrity of the V-MIL-47 is maintained during successive runs. The selectivity towards the epoxide is very high in these circumstances. Extensive computational modelling is performed to show that several reaction cycles are possible. EPR and NMR measurements confirm that at least two parallel catalytic cycles are co-existing: one with V +IV sites and one with pre-oxidized V +V sites, and this in complete agreement with the theoretical predictions.

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Section: Reaction Kinetics: Direct Versus Radical Pathwaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The coordinatively saturated vanadium MIL-47 as a low leaching heterogeneous catalyst in the oxidation of cyclohexene

Leus

Vandichel

Liu

et al. 2012

Journal of Catalysis

101

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“…Therefore, a breakthrough in this research area calls upon the synthesis of new nanostructured materials that can provide a stronger nanoscale effect. Metal-organic frameworks (MOFs) are promising candidates as new scaffolds due to their ordered crystalline lattice, adjustable pore sizes and acceptable thermal stabilities, as well as especially excellent catalytic performances [22]. It has been shown that metal clusters and hydrides could be confined in MOFs [23,24].…”

Section: Introductionmentioning

confidence: 99%

Improved hydrogen desorption properties of ammonia borane by Ni-modified metal-organic frameworks

Sun

et al. 2011

International Journal of Hydrogen Energy

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“…This product is formed due to a radical reaction pathway between the substrate and the oxidant TBHP and has been recently observed for unsaturated Co-MOFs. 10 Freely diffusing peroxy radicals can be generated by a variety of mechanisms in which the oxidation state of vanadium changes.…”

mentioning

confidence: 99%

The remarkable catalytic activity of the saturated metal organic framework V-MIL-47 in the cyclohexene oxidation

et al. 2010

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The remarkable catalytic activity of the saturated metal organic framework MIL-47 in the epoxidation of cyclohexene is elucidated by means of both experimental results and theoretical calculations.Metal organic frameworks (MOFs) are crystalline porous solids composed of a three-dimensional network of metal ions held in place by multidentate organic molecules. 1,2 Recently, the catalytic applications of MOFs have been reviewed by Hupp et al. and Farrusseng et al. 3,4 However, catalytic reaction mechanisms in metal organic frameworks and in particular at saturated coordinated centres are still poorly understood.In this study, we describe the high catalytic activity of a coordinative saturated V-MOF in the liquid phase oxidation of cyclohexene. The metal organic framework MIL-47 consists of a porous terephthalate framework built from infinite chains of V 4+ O 6 octahedra and has a three-dimensional orthorhombic structure that exhibits large pores. 5 Every structure unit in MIL-47 contains an O-V +IV -O bridge. The linkage of the V +IV to dicarboxylate groups of the terephthalate linkers results in an octahedral structure unit. Hence each vanadium(+IV) centre is saturated.The selective oxidation of cyclohexene is particularly interesting as it can yield, depending on the catalyst and the reaction conditions, several products as shown in Scheme 1. In this study, the reaction was carried out with tert-butyl hydroperoxide (70 wt% TBHP in water) as oxidant and chloroform as solvent. The internal standard used was 1,2,4-trichlorobenzene. The molar ratios were chloroform : cyclohexene : TBHP : 1,2,4-trichlorobenzene = 462 : 1 : 2 : 1. The reaction temperature was kept constant at 323 K. Samples were taken out from the reaction mixture at certain times and analyzed by gas chromatography. Next, MIL-47 was compared with a homogeneous vanadium catalyst vanadyl acetylacetonate VO(acac) 2 . Prior to the reaction, all the catalysts were dried under vacuum. Blank tests were performed without catalyst and no cyclohexene conversion was observed. Fig. 1 depicts the cyclohexene conversion and the detailed product distributions for MIL-47 and the homogeneous VO(acac) 2 catalyst. In both reactions, we used an identical amount of V-sites (0.4 mmol, 0.095 g MIL-47 and 0.106 g VO(acac) 2 ). The four main reaction products formed are cyclohexene oxide 2, cyclohexane-1,2-diol 3, tert-butyl-2-cyclohexenyl-1-peroxide 4 and 2-cyclohexen-1-one 5. From these figures it can be seen that the homogeneous catalyst VO(acac) 2 and the MIL-47 show high reaction rates for the conversion of cyclohexene. The initial turnover frequencies considered at the first 20 min are 57 h À1 and 43 h À1 for the VO(acac) 2 and the MIL-47 respectively. Both catalysts showed an almost linear conversion rate during the first 2 h of reaction and finally topped out at 60% conversion. The turnover numbers calculated at the end of the reaction were 62 and 68 for VO(acac) 2 and MIL-47 respectively. Moreover, considering the product distributions, truly interesting similaritie...

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Heterogeneous Catalytic Oxidation by MFU‐1: A Cobalt(II)‐Containing Metal–Organic Framework

Cited by 194 publications

References 47 publications

The coordinatively saturated vanadium MIL-47 as a low leaching heterogeneous catalyst in the oxidation of cyclohexene

The coordinatively saturated vanadium MIL-47 as a low leaching heterogeneous catalyst in the oxidation of cyclohexene

Improved hydrogen desorption properties of ammonia borane by Ni-modified metal-organic frameworks

The remarkable catalytic activity of the saturated metal organic framework V-MIL-47 in the cyclohexene oxidation

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