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  • 1.
    Bartoszewicz, Agnieszka
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Marcos, Rocio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Norrby, Per-Ola
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic Studies on the Alkylation of Amines with Alcohols Catalyzed by a Bifunctional Iridium Complex2015In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 5, no 6, p. 3704-3716Article in journal (Refereed)
    Abstract [en]

    The mechanism of the N-alkylation of amines with alcohols catalyzed by an iridium complex containing an N-heterocyclic carbene (NHC) ligand with a tethered alcohol/alkoxide functionality was investigated by a combination of experimental and computational methods. The catalyst resting state is an iridium hydride species containing the amine substrate as a ligand, and decoordination of the amine, followed by coordination of the imine intermediate to the iridium center, constitute the rate-determining step (rds) of the catalytic process. The alcohol/alkoxide that is tethered to the NHC participates in every step of the catalytic cycle by accepting or releasing protons and forming hydrogen bonds with the reacting species. Thus, the iridium complex with the alcohol/alkoxide tethered to the N-heterocyclic carbene ligand acts as a bifunctional catalyst.

  • 2.
    Carson, Fabian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Marcos, Rocio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jansson, Kjell
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martin-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Effect of the functionalisation route on a Zr-MOF with an Ir-NHC complex for catalysis2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 54, p. 10864-10867Article in journal (Refereed)
    Abstract [en]

    A new iridium N-heterocyclic carbene (NHC) metallolinker has been synthesised and introduced into a metal-organic framework (MOF), for the first time, via two different routes: direct synthesis and postsynthetic exchange (PSE). The two materials were compared in terms of the Ir loading and distribution using X-ray energy dispersive spectroscopy (EDS), the local Ir structure using X-ray absorption spectroscopy (XAS) and the catalytic activity. The materials showed good activity and recyclability as catalysts for the isomerisation of an allylic alcohol.

  • 3.
    Carson, Fabian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Marcos, Rocío
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jansson, Kjell
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Introduction of an N-heterocyclic Carbene Iridium Complex into a Zirconium Metal–Organic Framework for CatalysisManuscript (preprint) (Other academic)
  • 4.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Homogeneous and heterogeneous Cp*Ir(III) catalytic systems: Mechanistic studies of redox processes catalyzed by bifunctional iridium complexes, and synthesis of iridium-functionalized MOFs2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The purpose of this doctoral thesis is to investigate and develop catalytic processes mediated by iridium(III) complexes. By understanding the mechanisms, the weaknesses of the designed catalysts can be identified and be overcome in the following generation.

    The thesis is composed of two general sections dedicated to the synthesis and applications of homogeneous catalysts and to the preparation of heterogeneous catalysts based on metal-organic frameworks (MOFs). After a general introduction (Chapter 1), the first part of the thesis (Chapters 2-4, and Appendix 1) covers the use of several homogeneous bifunctional [Cp*Ir(III)] catalysts in a variety of chemical transformations, as well as mechanistic studies.

    Chapter 2 summarizes the studies on the N-alkylation of anilines with benzyl alcohols catalyzed by bifunctional Ir(III) complexes. Mechanistic investigations when the reactions were catalyzed by Ir(III) complexes with a hydroxy-functionalized N-heterocyclic carbene (NHC) ligand are discussed, followed by the design of a new generation of catalysts. The chapter finishes presenting the improved catalytic performance of these new complexes.   

    A family of these NHC-iridium complexes was evaluated in the acceptorless dehydrogenation of alcohols, as shown in Chapter 3. The beneficial effect of a co-solvent was investigated too. Under these base-free conditions, a wide scope of alcohols was efficiently dehydrogenated in excellent yields. The unexpected higher activity of the hydroxy-containing bifunctional NHC-Ir(III) catalysts, in comparison to that of the amino-functionalized one, was investigated experimentally.

    In the fourth chapter, the catalytic process presented in Chapter 3 was further explored on 1,4- and 1,5-diols, which were transformed into their corresponding tetrahydrofurans and dihydropyrans, respectively. Mechanistic investigations are also discussed.

    In the second part of the thesis (Chapter 5), a Cp*Ir(III) complex was immobilized into a MOF. The heterogenization of the metal complex was achieved efficiently, reaching high ratios of functionalization. However, a change in the topology of the MOF was observed. In this chapter, the use of advanced characterization techniques such as X-ray absorption spectroscopy (XAS) and pair distribution function (PDF) analyses enabled to study a phase transformation in these materials.

  • 5.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nonclassical cyclodehydration of diols assisted by metal-ligand cooperation2017Article in journal (Refereed)
  • 6.
    González Miera, Greco
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bermejo Gómez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Chupas, Peter J.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Chapman, Karena W.
    Platero-Prats, Ana E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Topological Transformation of a Metal–Organic Framework Triggered by Ligand Exchange2017In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, no 8, p. 4576-4583Article in journal (Refereed)
    Abstract [en]

    Here we describe the topological transformation of the pores of a new framework in the bio-MOF-100 family (dia-c) into the known isomer (lcs) by doubling the pore volume, which occurs during postsynthesis modifications. During this transformation, reassembling of the metal–organic framework (MOF) building blocks into a completely different framework occurs, involving breaking/forming of metal–ligand bonds. MOF crystallinity and local structure are retained, as determined by powder X-ray diffraction (PXRD) and pair distribution function (PDF) analyses, respectively. We exploited the inherent dynamism of bio-MOF-100 by coupling chemical decorations of the framework using solvent-assisted ligand exchange to the topological change. Following this method and starting from the pristine dense dia-c phase, open lcs-bio-MOF-100 was prepared and functionalized in situ with an iridium complex (IrL). Alternatively, the dia-c MOF could be modified with wide-ranging amounts of IrL up to ca. 50 mol %, as determined by solution 1H NMR spectroscopy, by tuning the concentration of the solutions used and with no evidence for isomer transformation. The single-site nature of the iridium complexes within the MOFs was assessed by X-ray absorption spectroscopy (XAS) and PDF analyses. Ligand exchanges occurred quantitatively at room temperature, with no need of excess of the iridium metallolinker.

  • 7.
    González Miera, Greco
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    López, Aitor Bermejo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Norrby, Per-Ola
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nonclassical Mechanism in the Cyclodehydration of Diols Catalyzed by a Bifunctional Iridium Complex2019In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 25, no 10, p. 2631-2636Article in journal (Refereed)
    Abstract [en]

    1,4- and 1,5-diols undergo cyclodehydration upon treatment with cationic N-heterocyclic carbene (NHC)-Ir-III complexes to give tetrahydrofurans and tetrahydropyrans, respectively. The mechanism was investigated, and a metal-hydride-driven pathway was proposed for all substrates, except for very electron-rich ones. This contrasts with the well-established classical pathways that involve nucleophilic substitution.

  • 8.
    González Miera, Greco
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Acceptorless Alcohol Dehydrogenation: OH vs NH Effect in Bifunctional NHC–Ir(III) Complexes2018In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 37, no 5, p. 636-644Article in journal (Refereed)
    Abstract [en]

    Bifunctional complexes bearing N-heterocyclic carbene (NHC) ligands functionalized with hydroxy or amine groups were synthesized to measure the beneficial effect of different modes of metal–ligand cooperation in the acceptorless dehydrogenation of alcohols. In comparison to complexes with an amine moiety, hydroxy-functionalized iridium catalysts showed superior activity. In contrast to alcohols, 1,4-diols underwent cyclization to give the corresponding tetrahydrofurans without involving dehydrogenation processes. Mechanistic investigations to rationalize the “OH effect” in these types of complexes have been undertaken.

  • 9. Mahanti, Bani
    et al.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martínez-Castro, Elisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bedin, Michele
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ott, Sascha
    Thapper, Anders
    Homogeneous Water Oxidation by Half-Sandwich Iridium(III) N-Heterocyclic Carbene Complexes with Pendant Hydroxy and Amino Groups2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4616-4623Article in journal (Refereed)
    Abstract [en]

    Herein, we report three (IrCp)-Cp-III* complexes with hydroxy-or amino-functionalized N-heterocyclic carbene (NHC) ligands that catalyze efficient water oxidation induced by addition of ceric ammonium nitrate (CAN). The pendant hydroxy or amino groups are very important for activity, and the complexes with heteroatom-functionalized NHC ligands show up to 15 times higher rates of oxygen evolution in CAN-induced water oxidation than a reference (IrCp)-Cp-III* complex without heteroatom functionalization. The formation of molecular high-valent Ir intermediates that are presumably involved in the rate-determining step for water oxidation is established by UV/Vis spectroscopy and ESI-MS under turnover conditions. The hydroxy groups on the NHC ligands, as well as chloride ligands on the iridium center are proposed to structurally stabilize the highvalent species, and thereby improve the catalytic activity. The Ir-III complex with a hydroxy-functionalized NHC shows the highest catalytic activity with a TON of 2500 obtained in 3 h and with >90% yield relative to the amount of oxidant used.

  • 10.
    Nagendiran, Anuja
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bermejo Gómez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Verho, Oscar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mild and Selective Catalytic Hydrogenation of the C=C Bond in a,b-Unsaturated Carbonyl Compounds Using Supported Palladium Nanoparticles2016In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 22, no 21, p. 7184-7189Article in journal (Refereed)
    Abstract [en]

    Chemoselective reduction of the C=C bond in a variety of α,β-unsaturated carbonyl compounds using supported palladium nanoparticles is reported. Three different heterogeneous catalysts were compared using 1 atm of H2: 1) nano-Pd on a metal–organic framework (MOF: Pd0-MIL-101-NH2(Cr)), 2) nano-Pd on a siliceous mesocellular foam (MCF: Pd0-AmP-MCF), and 3) commercially available palladium on carbon (Pd/C). Initial studies showed that the Pd@MOF and Pd@MCF nanocatalysts were superior in activity and selectivity compared to commercial Pd/C. Both Pd0-MIL-101-NH2(Cr) and Pd0-AmP-MCF were capable of delivering the desired products in very short reaction times (10–90 min) with low loadings of Pd (0.5–1 mol %). Additionally, the two catalytic systems exhibited high recyclability and very low levels of metal leaching.

  • 11.
    Pascanu, Vlad
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. University of Zurich, Switzerland.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Inge, A. Ken
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Metal-Organic Frameworks as Catalysts for Organic Synthesis: A Critical Perspective2019In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 141, no 18, p. 7223-7234Article, review/survey (Refereed)
    Abstract [en]

    Recent advances in organic chemistry and materials chemistry have enabled the porosity of new materials to be accurately controlled on the nanometer scale. In this context, metal-organic frameworks (MOFs) have rapidly become one of the most attractive classes of solid supports currently under investigation in heterogeneous catalysis. Their unprecedented degree of tunability gives MOFs the chance to succeed where others have failed. The past decade has witnessed an exponential growth in the complexity of new structures. MOFs with a variety of topologies and pore sizes show excellent stability across wide ranges of pH and temperature. Even the controlled insertion of defects, to alter the MOF's properties in a predictable manner, has become commonplace. However, research on catalysis with MOFs has been sluggish in catching up with modern trends in organic chemistry. Relevant issues such as enantioselective processes, C-H activation, or olefin metathesis are still rarely discussed. In this Perspective, we highlight meritorious examples that tackle important issues from contemporary organic synthesis, and that provide a fair comparison with existing catalysts. Some of these MOF catalysts already outcompete state-of-the-art homogeneous solutions. For others, improvements may still be required, but they have merit in aiming for the bigger challenge. Furthermore, we also identify some important areas where MOFs are likely to make a difference, by addressing currently unmet needs in catalysis instead of trying to outcompete homogeneous catalysts in areas where they excel. Finally, we strongly advocate for rational design of MOF catalysts, founded on a deep mechanistic understanding of the events taking place inside the pore.

  • 12. Roy, Souvik
    et al.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pullen, Sonja
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ott, Sascha
    Catalyst accessibility to chemical reductants in metal-organic frameworks2017In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 53, no 22, p. 3257-3260Article in journal (Refereed)
    Abstract [en]

    A molecular H-2-evolving catalyst, [Fe-2(cbdt)(CO)(6)] ([FeFe], cbdt = 3-carboxybenzene-1,2-dithiolate), has been attached covalently to an amino-functionalized MIL-101(Cr) through an amide bond. Chemical reduction experiments reveal that the MOF channels can be clogged by ion pairs that are formed between the oxidized reductant and the reduced catalyst. This effect is lessened in MIL-101-NH-[FeFe] with lower [FeFe] loadings. On longer timescales, it is shown that large proportions of the [FeFe] catalysts within the MOF engage in photochemical hydrogen production and the amount of produced hydrogen is proportional to the catalyst loading.

  • 13. Roy, Souvik
    et al.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pullen, Sonja
    González-Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ott, Sascha
    A MOF-Supported H2 Evolution Photocatalyst with Remarkable Stability and Improved EfficiencyArticle in journal (Refereed)
  • 14.
    Vico Solano, Marta
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    González Miera, Greco
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Inge, A. Ken
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martín‐Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Versatile Heterogeneous Palladium Catalysts for Diverse Carbonylation Reactions under Atmospheric Carbon Monoxide Pressure2018In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 10, no 5, p. 1089-1095Article in journal (Refereed)
    Abstract [en]

    Herein, we report a versatile carbonylation protocol using heterogeneous Pd-0 nanoparticles supported on the metal-organic frameworks (MOFs) MIL-88B-NH2 (Fe/Cr). The synthesis of a vast array of carbonyls, which includes amides, esters, carboxylic acids, and -ketoamides, was achieved through mono- and dicarbonylation reactions. The selectivity could be controlled simply by tuning the reaction conditions. Superior activity and selectivity were recorded in some cases compared to that achieved with commercial Pd/C. However, the utility of an elaborate catalyst support is questionable and important reactivity and recyclability issues are discussed.

1 - 14 of 14
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