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Sanchez Merlinsky L, Hemmeter D, Baraldo LM, Maier F, Steinrück HP, Williams FJ. Unlocking the Fluorine-Free Buoy Effect: Surface-Enriched Ruthenium Polypyridine Complexes in Ionic Liquids. ChemistryOpen 2024; 13:e202400092. [PMID: 38687137 PMCID: PMC11230926 DOI: 10.1002/open.202400092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Indexed: 05/02/2024] Open
Abstract
Controlling the local concentration of metal complexes at the surface of ionic liquids (ILs) is a highly sought-after objective due to its pivotal implications in supported ionic liquid phase (SILP) catalysis. Equally important is to avoid per- and polyfluorinated substances due to environmental concerns. Herein, we investigate the surface enrichment of Ru polypyridyl complexes with fluorine-free alkylic side groups of varying lengths and shapes, using the hydrophilic IL [C2C1Im][OAc] as solvent. Additional charged carboxylate groups are included into the polypyridyl ligands to increase the solubility of the complex in the IL. When the ligand system is functionalized with long and hydrophobic alkyl side chains, the complex predominantly localizes at the IL/vacuum interface, as deduced from angle-resolved X-ray photoelectron spectroscopy. Conversely, in the presence of short or more bulky substituents, no surface enrichment is observed. This buoy-like behaviour with fluorine-free side groups is explored for 0.05 %mol to 1 %mol solutions. Intriguingly, surface saturation occurs at approximately 0.5 %mol, which is beneficial to the efficient operation of catalytic systems featuring high surface areas, such as SILP catalysts.
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Affiliation(s)
- Luciano Sanchez Merlinsky
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía, CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Daniel Hemmeter
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, Erlangen, Germany
| | - Luis M Baraldo
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía, CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, Erlangen, Germany
| | - Federico J Williams
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía, CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
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Luo J, Kar S, Rauch M, Montag M, Ben-David Y, Milstein D. Efficient Base-Free Aqueous Reforming of Methanol Homogeneously Catalyzed by Ruthenium Exhibiting a Remarkable Acceleration by Added Catalytic Thiol. J Am Chem Soc 2021; 143:17284-17291. [PMID: 34617436 PMCID: PMC8532156 DOI: 10.1021/jacs.1c09007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 12/11/2022]
Abstract
Production of H2 by methanol reforming is of particular interest due the low cost, ready availability, and high hydrogen content of methanol. However, most current methods either require very high temperatures and pressures or strongly rely on the utilization of large amounts of base. Here we report an efficient, base-free aqueous-phase reforming of methanol homogeneously catalyzed by an acridine-based ruthenium pincer complex, the activity of which was unexpectedly improved by a catalytic amount of a thiol additive. The reactivity of this system is enhanced by nearly 2 orders of magnitude upon addition of the thiol, and it can maintain activity for over 3 weeks, achieving a total H2 turnover number of over 130 000. On the basis of both experimental and computational studies, a mechanism is proposed which involves outer-sphere dehydrogenations promoted by a unique ruthenium complex with thiolate as an assisting ligand. The current system overcomes the need for added base in homogeneous methanol reforming and also highlights the unprecedented acceleration of catalytic activity of metal complexes achieved by the addition of a catalytic amount of thiol.
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Affiliation(s)
- Jie Luo
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Sayan Kar
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Michael Rauch
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Michael Montag
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - Yehoshoa Ben-David
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
| | - David Milstein
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot, 76100, Israel
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3
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Schwarz CH, Kraus D, Alberico E, Junge H, Haumann M. Immobilized Ru‐Pincer Complexes for Continuous Gas‐Phase Low‐Temperature Methanol Reforming‐Improving the Activity by a Second Ru‐Complex and Variation of Hydroxide Additives. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Christian H. Schwarz
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Lehrstuhl für Chemische Reaktionstechnik (CRT) Egerlandstr. 3 91058 Erlangen Germany
| | - Dominik Kraus
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Lehrstuhl für Chemische Reaktionstechnik (CRT) Egerlandstr. 3 91058 Erlangen Germany
| | - Elisabetta Alberico
- Leibniz-Institut für Katalyse, e. V. Albert-Einstein Straße 29a 18059 Rostock Germany
- Istituto di Chimica Biomolecolare Consiglio Nazionale delle Ricerche tr. La Crucca 3 07100 Sassari Italy
| | - Henrik Junge
- Leibniz-Institut für Katalyse, e. V. Albert-Einstein Straße 29a 18059 Rostock Germany
| | - Marco Haumann
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Lehrstuhl für Chemische Reaktionstechnik (CRT) Egerlandstr. 3 91058 Erlangen Germany
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Carvalho FM, Kiametis AS, de Araújo Oliveira AL, Pirani F, Gargano R. Spectroscopy, lifetime, and charge-displacement of the methanol-noble gas complexes: An integrated experimental-theoretical investigation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 246:119049. [PMID: 33080517 DOI: 10.1016/j.saa.2020.119049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/08/2020] [Accepted: 10/02/2020] [Indexed: 05/26/2023]
Abstract
An integrated experimental-theoretical investigation was employed to determine rovibrational energies, spectroscopic constants, lifetime as a function of temperature in gas phase complexes of methanol with noble gas (NgHe, Ne, Ar, Kr, Xe, and Rn). Beside that, a parallel effort has been addressed to theoretically characterize the nature of intermolecular interactions determining the dissociation energy and equilibrium distance of the formed adducts. Dynamics and lifetime results reveal that, except for the CH3OH-He aggregate, all other methanol-Ng compounds are sufficiently stable under thermal conditions. Their lifetimes are larger than 1 ps for the temperature of the bulk in the range between 200 and 500 K. In addition, the current lifetime results suggest that the aggregates formed by methanol and Ng are globally more stable than corresponding complexes formed by water with Ng. From the point of view of the CCSD(T)/aug-cc-pVTZ level calculation, in all compounds, the electron densities of Ng partners are weakly polarized in the presence of CH3OH molecule. The charge-displacement curves and NBO analysis indicate that the charge transfer from Ng to methanol molecule, in general, plays a minor role, being appreciable only in the aggregate involving Ar. Finally, it was verified from the SAPT2 + (CCD)-δMP2/aug-cc-pVTZ calculations and NCI analysis that the dispersion is the essential long-range attractive contribution to the interaction energy for all studied complexes. This feature strongly suggests that these compounds are held bonded substantially by van der Waals forces. Then non-covalent intermolecular bonds are effectively formed in the gas phase, which is disturbed by small stabilizing charge-transfer contributions.
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Affiliation(s)
- Fernando M Carvalho
- Institute of Physics, University of Braslia, Campus Darcy Ribeiro, Braslia, DF, Brazil
| | | | | | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá degli studi di Perugia, via Elce di Sotto 8, Perugia, Italy; Istituto CNR di Scienze e Tecnologie Chimiche (CNR-SCITEC), via Elce di Sotto 8, Perugia, Italy
| | - Ricardo Gargano
- Institute of Physics, University of Braslia, Campus Darcy Ribeiro, Braslia, DF, Brazil.
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Abstract
Our planet urgently needs sustainable solutions to alleviate the anthropogenic global warming and climate change. Homogeneous catalysis has the potential to play a fundamental role in this process, providing novel, efficient, and at the same time eco-friendly routes for both chemicals and energy production. In particular, pincer-type ligation shows promising properties in terms of long-term stability and selectivity, as well as allowing for mild reaction conditions and low catalyst loading. Indeed, pincer complexes have been applied to a plethora of sustainable chemical processes, such as hydrogen release, CO2 capture and conversion, N2 fixation, and biomass valorization for the synthesis of high-value chemicals and fuels. In this work, we show the main advances of the last five years in the use of pincer transition metal complexes in key catalytic processes aiming for a more sustainable chemical and energy production.
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