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107. New directions in metal phosphonate and fhosphinate chemistry

Author

Shearan, Stephen J.I., Stock, Norbert, Emmerling, Franziska, Demel, Jan, Wright, Paul A., Demadis, Konstantinos D., Vassaki, Maria, Costantino, Ferdinando, Vivani, Riccardo, Sallard, Sébastien, Salcedo, Inés R., Cabeza-Diaz, Aurelio, and Taddei, Marco

Subjects
Fosfatos, Metal–organic frameworks, Baterías de estado sólido, Gas sorption/separation, Pilas de combustible, Rechargeable batteries, Hterogeneous catalysis, Synthesis, Metal phosphonates and phosphinate, X-ray and electron diffraction, Drug delivery, Layered materials, Conductividad eléctrica, In situ characterisation, Fósforo - Compuestos, Proton conduction
Abstract

In September 2018, the First EuropeanWorkshop on Metal Phosphonates Chemistry brought together some prominent researchers in the field of metal phosphonates and phosphinates with the aim of discussing past and current research e orts and identifying future directions. The scope of this perspective article is to provide a critical overview of the topics discussed during the workshop, which are divided into two main areas: synthesis and characterisation, and applications. In terms of synthetic methods, there has been a push towards cleaner and more e cient approaches. This has led to the introduction of high-throughput synthesis and mechanochemical synthesis. The recent success of metal–organic frameworks has also promoted renewed interest in the synthesis of porous metal phosphonates and phosphinates. Regarding characterisation, the main advances are the development of electron di raction as a tool for crystal structure determination and the deployment of in situ characterisation techniques, which have allowed for a better understanding of reaction pathways. In terms of applications, metal phosphonates have been found to be suitable materials for several purposes: they have been employed as heterogeneous catalysts for the synthesis of fine chemicals, as solid sorbents for gas separation, notably CO2 capture, as materials for electrochemical devices, such as fuel cells and rechargeable batteries, and as matrices for drug delivery.

Published
2019

108. In situ XAS study of the local structure and oxidation state evolution of palladium in a reduced graphene oxide supported Pd(II) carbene complex during an undirected C–H acetoxylation reaction

Author

Yuan, Ning, Majeed, Maitham H., Bajnóczi, Éva G., Persson, Axel R., Wallenberg, L. Reine, Inge, A. Ken, Heidenreich, Niclas, Stock, Norbert, Zou, Xiaodong, Wendt, Ola F., and Persson, Ingmar

Subjects
Inorganic Chemistry, ddc:540
Abstract

Catalysis science & technology 9(8), 2025 - 2031 (2019). doi:10.1039/C8CY02430H, In situ X-ray absorption spectroscopy (XAS) investigations have been performed to provide insights into the reaction mechanism of a palladium(II) catalyzed undirected C–H acetoxylation reaction in the presence of an oxidant. A Pd(II) N-heterocyclic carbene complex π-stacked onto reduced graphene oxide (rGO) was used as the catalyst. The Pd speciation during the catalytic process was examined by XAS, which revealed a possible mechanism over the course of the reaction. Pd(II) complexes in the as-synthesized catalyst first go through a gradual ligand substitution where chloride ions bound to Pd(II) are replaced by other ligands with a mean bond distance to Pd matching Pd–C/N/O. Parallel to this the mean oxidation state of Pd increases indicating the formation of Pd(IV) species. At a later stage, a fraction of the Pd complexes start to slowly transform into Pd nanoclusters. The mean average oxidation state of Pd decreases to the initial state at the end of the experiment which means that comparable amounts of Pd(0) and Pd(IV) are present. These observations from heterogeneous catalysis are in good agreement with its homogeneous analog and they support a Pd(II)–Pd(IV)–Pd(II) reaction mechanism., Published by RSC Publ., London

Published
2019
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117. Probing the Evolution of Palladium Species in Pd@MOF Catalysts during the Heck Coupling Reaction: An Operando X-ray Absorption Spectroscopy Study

Author

Yuan, Ning, Pascanu, Vlad, Martín-Matute, Belén, Zou, Xiaodong, Huang, Zhehao, Valiente, Alejandro, Heidenreich, Niclas, Leubner, Sebastian, Inge, A. Ken, Gaar, Jakob, Stock, Norbert, and Persson, Ingmar

Subjects
ddc:540
Abstract

Journal of the American Chemical Society 140(26), 8206 - 8217 (2018). doi:10.1021/jacs.8b03505, The mechanism of the Heck C���C coupling reaction catalyzed by Pd@MOFs has been investigated using operando X-ray absorption spectroscopy (XAS) and powder X-ray diffraction (PXRD) combined with transmission electron microscopy (TEM) analysis and nuclear magnetic resonance (1H NMR) kinetic studies. A custom-made reaction cell was used, allowing operando PXRD and XAS data collection using high-energy synchrotron radiation. By analyzing the XAS data in combination with ex situ studies, the evolution of the palladium species is followed from the as-synthesized to its deactivated form. An adaptive reaction mechanism is proposed. Mononuclear Pd(II) complexes are found to be the dominant active species at the beginning of the reaction, which then gradually transform into Pd nanoclusters with 13���20 Pd atoms on average in later catalytic turnovers. Consumption of available reagent and substrate leads to coordination of Cl$^���$ ions to their surfaces, which causes the poisoning of the active sites. By understanding the deactivation process, it was possible to tune the reaction conditions and prolong the lifetime of the catalyst., Published by American Chemical Society, Washington, DC

Published
2018
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118. Layered Lanthanide Sulfophosphonates and Their Proton Conduction Properties in Membrane Electrode Assemblies

Author

Bazaga-García, Montse, primary, Salcedo, Inés R., additional, Colodrero, Rosario M. P., additional, Xanthopoulos, Konstantinos, additional, Villemin, Didier, additional, Stock, Norbert, additional, López-González, Mar, additional, del Río, Carmen, additional, Losilla, Enrique R., additional, Cabeza, Aurelio, additional, Demadis, Konstantinos D., additional, and Olivera-Pastor, Pascual, additional

Published
2019
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121. Aqueous Flow Reactor and Vapour-Assisted Synthesis of Aluminium Dicarboxylate Metal-Organic Frameworks for Use as Water Adsorbents

Author

Stassin, Timothée, primary, Waitschat, Steve, primary, Heidenreich, Niclas, primary, Reinsch, Helge, primary, Puschkell, Finn, primary, Kravchenko, Dmitry, primary, Stassen, Ivo, primary, van Dinter, Jonas, primary, Verbeke, Rhea, primary, Dickmann, Marcel, primary, Egger, Werner, primary, Vankelecom, Ivo, primary, De Vos, Dirk, primary, Ameloot, Rob, primary, and Stock, Norbert, primary

Published
2019
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122. Systematically Designed Periodic Electrophoretic Deposition for Decorating 3D Carbon-Based Scaffolds with Bioactive Nanoparticles

Author

Taale, Mohammadreza, primary, Krüger, Diana, additional, Ossei-Wusu, Emmanuel, additional, Schütt, Fabian, additional, Rehman, Muhammad Atiq Ur, additional, Mishra, Yogendra Kumar, additional, Marx, Janik, additional, Stock, Norbert, additional, Fiedler, Bodo, additional, Boccaccini, Aldo R., additional, Willumeit-Römer, Regine, additional, Adelung, Rainer, additional, and Selhuber-Unkel, Christine, additional

Published
2019
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123. New Directions in Metal Phosphonate and Phosphinate Chemistry

Author

Shearan, Stephen J.I., primary, Stock, Norbert, additional, Emmerling, Franziska, additional, Demel, Jan, additional, Wright, Paul A., additional, Demadis, Konstantinos D., additional, Vassaki, Maria, additional, Costantino, Ferdinando, additional, Vivani, Riccardo, additional, Sallard, Sébastien, additional, Ruiz Salcedo, Inés, additional, Cabeza, Aurelio, additional, and Taddei, Marco, additional

Published
2019
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126. Reversible Optical Writing and Data Storage in an Anthracene‐Loaded Metal–Organic Framework

Author

Tu, Min, primary, Reinsch, Helge, additional, Rodríguez‐Hermida, Sabina, additional, Verbeke, Rhea, additional, Stassin, Timothée, additional, Egger, Werner, additional, Dickmann, Marcel, additional, Dieu, Bjorn, additional, Hofkens, Johan, additional, Vankelecom, Ivo F. J., additional, Stock, Norbert, additional, and Ameloot, Rob, additional

Published
2019
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127. Metal–organic frameworks in Germany: From synthesis to function

Author

Evans, Jack D., primary, Garai, Bikash, additional, Reinsch, Helge, additional, Li, Weijin, additional, Dissegna, Stefano, additional, Bon, Volodymyr, additional, Senkovska, Irena, additional, Fischer, Roland A., additional, Kaskel, Stefan, additional, Janiak, Christoph, additional, Stock, Norbert, additional, and Volkmer, Dirk, additional

Published
2019
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129. Five New Coordination Polymers with a Bifunctional Phosphonate-Sulfonate Linker Molecule

Author

Wöhlbrandt, Stephan, Beyer, Ole, Reinsch, Helge, Inge, A. Ken, Svensson Grape, Erik, Lüning, Ulrich, Stock, Norbert, Wöhlbrandt, Stephan, Beyer, Ole, Reinsch, Helge, Inge, A. Ken, Svensson Grape, Erik, Lüning, Ulrich, and Stock, Norbert

Abstract

The bifunctional linker molecule [5-(phosphonomethyl)-2,4-bis(sulfonomethyl)phenyl]methanesulfonic acid (HO3S-CH2)(3)-C6H2-CH2PO3H2 (abbreviated as H(5)L4) was employed in systematic high-throughput investigations in order to discover new coordination polymers (CPs). Employing 27 metal salts of 17 different metals in this investigation, five new compounds [Mg-2(HL4)(H2O)(6)] (1), [Pb-4(L4)(OH)(3)] (2), [Ba-2(H(2)L4)(OH)(H2O)] (3), [Ba-2(HL4)(H2O)(4)] (4), and [Cd-2,Cd-5(L4)(H2O)(7)] (5) were discovered and their crystal structures were determined. In all compounds, the sulfonate and phosphonate groups could not be resolved since the P and S atoms are statistically occupying the atom site with a ratio of 0.25 to 0.75. This is reflected in the P-O and S-O bond lengths. Four of the structures were determined from single-crystal X-ray diffraction data, whereas the structure of 4 was solved ab initio from powder data using real-space methods and refined using Rietveld methods.

Published
2019
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130. In Situ XAS Study of the Local Structure and Oxidation State Evolutions of Palladium in a Reduced Graphene Oxide Supported Pd(II) Carbene Complex during an Undirected C−H Acetoxylation Reaction

Author

Yuan, Ning, Majeed, Maitham H., Bajnóczi, Éva G., Persson, Axel R., Wallenberg, L. Reine, Ken Inge, Andrew, Heidenreich, Niclas, Stock, Norbert, Zou, Xiaodong, Wendt, Ola F., Persson, Ingmar, Yuan, Ning, Majeed, Maitham H., Bajnóczi, Éva G., Persson, Axel R., Wallenberg, L. Reine, Ken Inge, Andrew, Heidenreich, Niclas, Stock, Norbert, Zou, Xiaodong, Wendt, Ola F., and Persson, Ingmar

Abstract

In situ X-ray absorption spectroscopy (XAS) investigations have been performed to provide insights into the reaction mechanism of a palladium(II) catalyzed undirected C–H acetoxylation reaction in the presence of an oxidant. A Pd(II) N-heterocyclic carbene complex p-stacked onto reduced graphene oxide (rGO) was used as catalyst. The Pd speciation during the catalytic process was examined by XAS, which revealed a possible mechanism over the course of the reaction. Pd(II) complexes in the as-synthesized catalyst first go through a gradual ligand substitution where chloride ions bound to Pd(II) are replaced by other ligands with a bond distance to Pd corresponding to carbon, nitrogen and/or oxygen (L). Parallel to this the mean oxidation state of Pd increases indicating the formation of Pd(IV) species. At a later stage, a fraction of the Pd complexes start to slowly transform into Pd nanoclusters. The mean average oxidation state of Pd decreases to the initial state at the end of the experiment which means that comparable amounts of Pd(0) and Pd(IV) are present. These observations from heterogeneous catalysis are in good agreement with its homogeneous analog and they support a Pd(II)-Pd(IV)-Pd(II) reaction mechanism.

Published
2019
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131. Metal-Organic Frameworks in Germany: From Synthesis to Function

Author

Evans, Jack. D., Garai, Bikash, Reinsch, Helge, Li, Weijin, Disegna, Stefano, Bon, Volodymyr, Senkovska, Irena, Fischer, Roland A., Kaskel, Stefan, Janiak, Christoph, Stock, Norbert, Volkmer, Dirk, Evans, Jack. D., Garai, Bikash, Reinsch, Helge, Li, Weijin, Disegna, Stefano, Bon, Volodymyr, Senkovska, Irena, Fischer, Roland A., Kaskel, Stefan, Janiak, Christoph, Stock, Norbert, and Volkmer, Dirk

Abstract

Metal–organic frameworks (MOFs) are constructed from a combination of inorganic and organic units to produce materials which display high porosity, among other unique and exciting properties. MOFs have shown promise in many wide ranging applications, such as catalysis and gas separations. In this review, we highlight MOF research conducted by Germany-based research groups. Specifically, we feature approaches for the synthesis of new MOFs, high-throughput MOF production, advanced characterization methods and examples of advanced functions and properties.:1. Introduction 2. Chemistry and materials 3. Towards an industrial scale 4. Advanced characterization 5. Advanced function 6. Conclusion Acknowledgements References

Published
2019

133. In Situ X‐ray Diffraction Investigation of the Crystallisation of Perfluorinated CeIV‐Based Metal–Organic Frameworks with UiO‐66 and MIL‐140 Architectures**.

Author

Shearan, Stephen J. I., Jacobsen, Jannick, Costantino, Ferdinando, D'Amato, Roberto, Novikov, Dmitri, Stock, Norbert, Andreoli, Enrico, and Taddei, Marco

Subjects
METAL-organic frameworks, X-ray diffraction, CRYSTALLIZATION, X-ray powder diffraction, CRYSTAL growth, AMMONIUM acetate
Abstract

We report on the results of an in situ synchrotron powder X‐ray diffraction study of the crystallisation in aqueous medium of two recently discovered perfluorinated CeIV‐based metal–organic frameworks (MOFs), analogues of the already well investigated ZrIV‐based UiO‐66 and MIL‐140A, namely, F4_UiO‐66(Ce) and F4_MIL‐140A(Ce). The two MOFs were originally obtained in pure form in similar conditions, using ammonium cerium nitrate and tetrafluoroterephthalic acid as reagents, and small variations of the reaction parameters were found to yield mixed phases. Here, we investigate the crystallisation of these compounds, varying parameters such as temperature, amount of the protonation modulator nitric acid and amount of the coordination modulator acetic acid. When only HNO3 is present in the reaction environment, only F4_MIL‐140A(Ce) is obtained. Heating preferentially accelerates nucleation, which becomes rate determining below 57 °C. Upon addition of AcOH to the system, alongside HNO3, mixed‐phased products are obtained. F4_UiO‐66(Ce) is always formed faster, and no interconversion between the two phases occurs. In the case of F4_UiO‐66(Ce), crystal growth is always the rate‐determining step. A higher amount of HNO3 favours the formation of F4_MIL‐140A(Ce), whereas increasing the amount of AcOH favours the formation of F4_UiO‐66(Ce). Based on the in situ results, a new optimised route to achieving a pure, high‐quality F4_MIL‐140A(Ce) phase in mild conditions (60 °C, 1 h) is also identified. [ABSTRACT FROM AUTHOR]

Published
2021
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134. [M2(μ‐OH)2(DHBQ)3] (M = Zr, Hf) ‐ Two New Isostructural Coordination Polymers based on the Unique M2O14 Inorganic Building Unit and 2,5‐Dioxido‐p‐benzoquinone as Linker Molecule

Author

Poschmann, Mirjam P. M., Reinsch, Helge, and Stock, Norbert

Abstract

Two new isostructural porous coordination polymers (CPs) were obtained under solvothermal reaction conditions using 2,5‐dihydroxy‐p‐benzoquinone (H2DHBQ) or 1,2,4,5‐tetrahydroxybenzene (H4THB) as linker molecule and Zr4+ or Hf4+ salts. Highly crystalline compounds with composition [M2(μ‐OH)2(DHBQ)3]·xH2O (M = Zr4+ or Hf4+, x = 0–3.6/3.3) were found in a wide temperature range (120–200 °C) and a reaction time of 70 h. The crystal structures were determined ab initio from powder X‐ray diffraction data and the oxidation state of the linker was confirmed spectroscopically. The dinuclear inorganic building unit M2O14 is new for Zr‐ and Hf‐CPs. For both compounds a full characterization was carried out, i.e. crystal structure determination, spectroscopic measurements, elemental‐ and thermogravimetric analyses. [M2(OH)2(DHBQ)3] (M = Zr4+ or Hf4+) is stable up to 250 and 220 °C, respectively. Water sorption measurements proofed an uptake of 3.6 mol H2O per mol and 3.3 mol H2O per mol, respectively. [ABSTRACT FROM AUTHOR]

Published
2021
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135. A Flexible and Porous Ferrocene‐Based Gallium MOF with MIL‐53 Architecture.

Author

Benecke, Jannik, Fuß, Alexander, Engesser, Tobias A., Stock, Norbert, and Reinsch, Helge

Subjects
GALLIUM, X-ray powder diffraction, CHEMICAL formulas, METAL-organic frameworks, SURFACE area, IODINE
Abstract

A new gallium based metal‐organic framework, denoted as Ga‐MIL‐53‐FcDC, with the chemical formula [Ga(OH)(FeC12H8O4)] was synthesized using the ferrocene containing linker molecule 1,1'‐ferrocenedicarboxylic acid (H2FcDC, FeC12H10O4). The porous nature of the compound could be confirmed by nitrogen sorption and a specific surface area of 270 m2/g was determined. The persistence of the ferrocene complex inside the structure was confirmed by Mössbauer‐, EPR and UV/VIS‐spectroscopy. Ga‐MIL‐53‐FcDC shows structural flexibility depending on which guest molecule is located in the pores of the compound. The mechanism of structural flexibility was analyzed by means of powder X‐ray diffraction adsorbing pyrazine or iodine. The flexibility of the crystal structure can be attributed to the torsion of the GaO6 octahedra in the IBU respective to each other and the torsion of the carboxylate groups of FcDC2− relative to the aromatic ring. [ABSTRACT FROM AUTHOR]

Published
2021
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136. The Influence of Isomerism on Crystallization in Aluminum Pyridinedicarboxylate Coordination Compounds

Author

Wharmby, Michael T. and Stock, Norbert

Subjects
ddc:540
Abstract

Zeitschrift für anorganische und allgemeine Chemie 644(24), 1816 - 1825 (2018). doi:10.1002/zaac.201800353, The reactions of three isomeric pyridinedicarboxylic acid linkers - 2,4-, 2,6-, and 3,5-pyridinedicarboxylic acid - with various aluminum salts were investigated by high-throughput solvothermal synthesis. Two coordination compounds were obtained from the symmetrical linkers (2,6- and 3,5-pyridinedicarboxylic acid). The former is based on molecular Al-O dimers, similar to those reported in the coordination polymer CAU-16. The latter forms a porous extended framework and is a member of the CAU-10 family of compounds. Full characterization of both compounds is reported. Crystal structures were determined from high-resolution synchrotron powder diffraction data. The number of guest water molecules determined crystallographically is in excellent agreement with the number found by thermogravimetric and elemental analyses. It was found that the CAU-10 analogue undergoes a reversible, displacive phase transition from a non-centrosymmetric to a centrosymmetric space group on loss of guest water molecules, due to guest-framework interactions., Published by Wiley-VCH, Weinheim

Published
2018
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137. New multifunctional sulfonato-containing metal phosphonates proton conductors

Author

Ruiz Salcedo, Inés, Bazaga García, Montse, Pérez Colodrero, Rosario Mercedes, Xanthopoulos, Konstantinos, Demadis, Konstantinos, Stock, Norbert, Cabeza-Diaz, Aurelio, Ramirez-Losilla, Enrique, and Olivera-Pastor, Pascual

Subjects
Metal phosphonates, Coordination polymers, Proton conductivity, Hybrid materials, Protones
Abstract

Anchoring of acidic functional groups to organic linkers acting as ligands in metal phosphonates has been demonstrate to be a valid strategy to develop new proton conductor materials, which exhibit tunable properties and are potentially applicable to proton exchange membranes, such as those used in PEMFCs [1,2]. In this work, the structural and proton conductivity properties of several families of divalent and trivalent metal amino-sulfophosphonates are presented. The chosen ligand, (H2O3PCH2)2-N-(CH2)2-SO3H, was reacted with the appropriate metal salt using highthrough-put screening and/or microwave-assisted synthesis. Different crystal structures haven been solved displaying a variety of metal ligand coordination modes, in whose frameworks acidic groups contribute to create strong H-bond networks; together with lattice and bound water molecules. Proton conductivity values oscillate between 10-4 and 10-2 S.cm-1, at 80 ºC and 95 % relative humidity, most of them showing activation energies characteristic of a Grotthuss-type proton transport mechanism. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. MINECO: MAT2016-77648-R Junta de Andalucía: P-12-FQM-1656 y FQM-113

Published
2018

142. In situ XAS study of the local structure and oxidation state evolution of palladium in a reduced graphene oxide supported Pd(ii) carbene complex during an undirected C–H acetoxylation reaction

Author

Yuan, Ning, primary, Majeed, Maitham H., additional, Bajnóczi, Éva G., additional, Persson, Axel R., additional, Wallenberg, L. Reine, additional, Inge, A. Ken, additional, Heidenreich, Niclas, additional, Stock, Norbert, additional, Zou, Xiaodong, additional, Wendt, Ola F., additional, and Persson, Ingmar, additional

Published
2019
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