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Influence of the Base on Pd@MIL-101-NH2(Cr) as Catalyst for the Suzuki-Miyaura Cross-Coupling Reaction
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Visa övriga samt affilieringar
2015 (Engelska)Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, nr 30, s. 10896-10902Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The chemical stability of metal-organic frameworks (MOFs) is a major factor preventing their use in industrial processes. Herein, it is shown that judicious choice of the base for the Suzuki-Miyaura cross-coupling reaction can avoid decomposition of the MOF catalyst Pd@MIL-101-NH2(Cr). Four bases were compared for the reaction: K2CO3, KF, Cs2CO3 and CsF. The carbonates were the most active and achieved excellent yields in shorter reaction times than the fluorides. However, powder XRD and N-2 sorption measurements showed that the MOF catalyst was degraded when carbonates were used but remained crystalline and porous with the fluorides. XANES measurements revealed that the trimeric chromium cluster of Pd@MIL-101-NH2(Cr) is still present in the degraded MOF. In addition, the different countercations of the base significantly affected the catalytic activity of the material. TEM revealed that after several catalytic runs many of the Pd nanoparticles (NPs) had migrated to the external surface of the MOF particles and formed larger aggregates. The Pd NPs were larger after catalysis with caesium bases compared to potassium bases.

Ort, förlag, år, upplaga, sidor
2015. Vol. 21, nr 30, s. 10896-10902
Nyckelord [en]
cross-coupling, heterogeneous catalysis, metal-organic frameworks, nanoparticles, palladium
Nationell ämneskategori
Kemi
Forskningsämne
organisk kemi
Identifikatorer
URN: urn:nbn:se:su:diva-119544DOI: 10.1002/chem.201500843ISI: 000357984900039OAI: oai:DiVA.org:su-119544DiVA, id: diva2:847432
Forskningsfinansiär
VetenskapsrådetVINNOVAKnut och Alice Wallenbergs StiftelseTillgänglig från: 2015-08-20 Skapad: 2015-08-17 Senast uppdaterad: 2018-03-12Bibliografiskt granskad
Ingår i avhandling
1. Catalytic Processes Mediated by Metal−Organic Frameworks: Reactivity and Mechanistic Studies
Öppna denna publikation i ny flik eller fönster >>Catalytic Processes Mediated by Metal−Organic Frameworks: Reactivity and Mechanistic Studies
2016 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The present thesis describes the development of heterogeneous catalytic methodologies using metal−organic frameworks (MOFs) as porous matrices for supporting transition metal catalysts. A wide spectrum of chemical reactions is covered. Following the introductory section (Chapter 1), the results are divided between one descriptive part (Chapter 2) and four experimental parts (Chapters 3–6).

Chapter 2 provides a detailed account of MOFs and their role in heterogeneous catalysis. Specific synthesis methods and characterization techniques that may be unfamiliar to organic chemists are illustrated based on examples from this work.

Pd-catalyzed heterogeneous C−C coupling and C−H functionalization reactions are studied in Chapter 3, with focus on their practical utility. A vast functional group tolerance is reported, allowing access to substrates of relevance for the pharmaceutical industry. Issues concerning the recyclability of MOF-supported catalysts, leaching and operation under continuous flow are discussed in detail.

The following chapter explores puzzling questions regarding the nature of the catalytically active species and the pathways of deactivation for Pd@MOF catalysts. These questions are addressed through detailed mechanistic investigations which include in situ XRD and XAS data acquisition. For this purpose a custom reaction cell is also described in Chapter 4.

The scope of Pd@MOF-catalyzed reactions is expanded in Chapter 5. A strategy for boosting the thermal and chemical robustness of MOF crystals is presented. Pd@MOF catalysts are coated with a protecting SiO2 layer, which improves their mechanical properties without impeding diffusion. The resulting nanocomposite is better suited to withstand the harsh conditions of aerobic oxidation reactions. In this chapter, the influence of the nanoparticles’ geometry over the catalyst’s selectivity is also investigated.

While Chapters 3–5 dealt with Pd-catalyzed processes, Chapter 6 introduces hybrid materials based on first-row transition metals. Their reactivity is explored towards light-driven water splitting. The heterogenization process leads to stabilized active sites, facilitating the spectroscopic probing of intermediates in the catalytic cycle.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Organic Chemistry, Stockholm University, 2016. s. 122
Nationell ämneskategori
Organisk kemi
Forskningsämne
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-132711 (URN)978-91-7649-485-1 (ISBN)
Disputation
2016-10-07, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Submitted. Paper 8: Submitted.

 

Tillgänglig från: 2016-09-14 Skapad: 2016-08-19 Senast uppdaterad: 2017-02-03Bibliografiskt granskad
2. Development of Metal–Organic Frameworks for Catalysis: Designing Functional and Porous Crystals
Öppna denna publikation i ny flik eller fönster >>Development of Metal–Organic Frameworks for Catalysis: Designing Functional and Porous Crystals
2015 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Metal–organic frameworks, or MOFs, have emerged as a new class of porous materials made by linking metal and organic units. The easy preparation, structural and functional tunability, ultrahigh porosity, and enormous surface areas of MOFs have led to them becoming one of the fastest growing fields in chemistry. MOFs have potential applications in numerous areas such as clean energy, adsorption and separation processes, biomedicine, and sensing. One of the most promising areas of research with MOFs is heterogeneous catalysis.

This thesis describes the design and synthesis of new, carboxylate-based MOFs for use as catalysts. These materials have been characterized using diffraction, spectroscopy, adsorption, and imaging techniques. The thesis has focused on preparing highly-stable MOFs for catalysis, using post-synthetic methods to modify the properties of these crystals, and applying a combination of characterization techniques to probe these complex materials.

In the first part of this thesis, several new vanadium MOFs have been presented. The synthesis of MIL-88B(V), MIL-101(V), and MIL-47 were studied using ex situ techniques to gain insight into the synthesis–structure relationships. The properties of these materials have also been studied.

In the second part, the use of MOFs as supports for metallic nanoparticles has been investigated. These materials, Pd@MIL-101–NH2(Cr) and Pd@MIL-88B–NH2(Cr), were used as catalysts for Suzuki–Miyaura and oxidation reactions, respectively. The effect of the base on the catalytic activity, crystallinity, porosity, and palladium distribution of Pd@MIL-101–NH2(Cr) was studied.

In the final part, the introduction of transition-metal complexes into MOFs through different synthesis routes has been described. A ruthenium complex was grafted onto an aluminium MOF, MOF-253, and an iridium metallolinker was introduced into a zirconium MOF, UiO-68–2CH3. These materials were used as catalysts for alcohol oxidation and allylic alcohol isomerization, respectively.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Materials and Environmental Chemistry (MMK), Stockkholm University, 2015. s. 144
Nyckelord
Metal–organic frameworks, heterogeneous catalysis, nanoparticles, metallolinkers, postsynthetic modification, postsynthetic exchange
Nationell ämneskategori
Oorganisk kemi
Forskningsämne
oorganisk kemi
Identifikatorer
urn:nbn:se:su:diva-115819 (URN)978-91-7649-166-9 (ISBN)
Externt samarbete:
Disputation
2015-06-05, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Manuscript.

Tillgänglig från: 2015-05-13 Skapad: 2015-04-01 Senast uppdaterad: 2016-08-26Bibliografiskt granskad

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