Structure and properties of tungsten peroxopolyoxo complexes – promising catalysts for organics oxidation. II: Cation type influence on the tungsten peroxocomplex structure

Kochubey, D. I.; Berdnikova, P. V.; Pai, Z. P.; Chesalov, Yu. A.; Kanazhevskiy, Vladislav V.; Khlebnikova, T. B.

doi:10.1016/j.molcata.2012.10.013

Cited by 15 publications

(4 citation statements)

References 13 publications

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“…2C support that the W coordination shells of CN-PTA are similar to that of PTA clusters. In addition, the peak at 1.2 Å can be assigned to the tungsten-oxygen bond ( 24 ), but W─O and W═O are indistinguishable due to the influence of interaction between the oxygen atoms and surface ligands ( 25 ). Moreover, the strong feature centered around 3.2 Å is assigned to W─O─W scattering in CN-PTA and PTA clusters ( 24 ).…”

Section: Resultsmentioning

confidence: 99%

A monolayer crystalline covalent network of polyoxometalate clusters

Hao-Yang

Zheng

et al. 2023

Sci. Adv.

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Monolayer two-dimensional (2D) materials are of great interest because of their unique electronic structures, noticeable in-plane confinement effect, and exceptional catalytic properties. Here, we prepared 2D covalent networks of polyoxometalate clusters (CN-POM) featuring monolayer crystalline molecular sheets, formed by the covalent connection between tetragonally arranged POM clusters. The CN-POM shows a superior catalytic efficiency in the oxidation of benzyl alcohol, and the conversion rate is five times higher than that of the POM cluster units. Theoretical calculations show that in-plane electron delocalization of CN-POM contributes to easier electron transfer and increases catalytic efficiency. Moreover, the conductivity of the covalently interconnected molecular sheets was 46 times greater than that of individual POM clusters. The preparation of monolayer covalent network of POM clusters provides a strategy to synthesize advanced cluster-based 2D materials and a precise molecular model to investigate the electronic structure of crystalline covalent networks.

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Section: Resultsmentioning

confidence: 99%

A monolayer crystalline covalent network of polyoxometalate clusters

Hao-Yang

Zheng

et al. 2023

Sci. Adv.

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“…EXAFS results support the presence of WO x clusters in PW 12 @NU-1000 and isolated W atoms in W-SIM. Although the W coordination shells could not be readily fit in a quantitative manner, a strong feature centered around 3.2 Å in Figure a has been assigned to W–O–W scattering in WO x clusters . On the other hand, W-SIM does not present strong features in this regime, indicating negligible WO x cluster formation (Table ).…”

Section: Resultsmentioning

confidence: 99%

“…Although the W coordination shells could not be readily fit in a quantitative manner, a strong feature centered around 3.2 Å in Figure 4a has been assigned to W−O−W scattering in WO x clusters. 53 On the other hand, W-SIM does not present strong features in this regime, indicating negligible WO x cluster formation (Table 1). Furthermore, the two peaks at 1.2 and 1.5 Å in Figure 4b are assigned to WO and WO, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Pushing the Limits on Metal–Organic Frameworks as a Catalyst Support: NU-1000 Supported Tungsten Catalysts for o-Xylene Isomerization and Disproportionation

et al. 2018

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Acid-catalyzed skeletal C-C bond isomerizations are important benchmark reactions for the petrochemical industries. Among those, o-xylene isomerization/disproportionation is a probe reaction for strong Brønsted acid catalysis, and it is also sensitive to the local acid site density and pore topology. Here, we report on the use of phosphotungstic acid (PTA) encapsulated within NU-1000, a Zr-based metal-organic framework (MOF), as a catalyst for o-xylene isomerization at 523 K. Extended X-ray absorption fine structure (EXAFS), P NMR, N physisorption, and X-ray diffraction (XRD) show that the catalyst is structurally stable with time-on-stream and that WO clusters are necessary for detectable rates, consistent with conventional catalysts for the reaction. PTA and framework stability under these aggressive conditions requires maximal loading of PTA within the NU-1000 framework; materials with lower PTA loading lost structural integrity under the reaction conditions. Initial reaction rates over the NU-1000-supported catalyst were comparable to a control WO-ZrO, but the NU-1000 composite material was unusually active toward the transmethylation pathway that requires two adjacent active sites in a confined pore, as created when PTA is confined in NU-1000. This work shows the promise of metal-organic framework topologies in giving access to unique reactivity, even for aggressive reactions such as hydrocarbon isomerization.

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“…That is because the vibration bands of the N + R 4 cation are sensitive to local interactions to Cl À . 17,18 The existence of IBr will disturb the cation-anion interactions in TEAC, which might influence the force constant of the N + -C stretching mode. Similar results could be observed with other XDES systems as well (Fig.…”

mentioning

confidence: 99%