1
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Radicke J, Busse K, Jerschabek V, Hashemi Haeri H, Abu Bakar M, Hinderberger D, Kressler J. 1-Ethyl-3-methylimidazolium Acetate as a Reactive Solvent for Elemental Sulfur and Poly(sulfur nitride). J Phys Chem B 2024; 128:5700-5712. [PMID: 38822794 PMCID: PMC11182232 DOI: 10.1021/acs.jpcb.4c01536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/03/2024]
Abstract
We investigate the reactive dissolution process of poly(sulfur nitride) (SN)x in the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate [EMIm][OAc] in comparison to the process of elemental sulfur in the same IL. It has been known from the literature that during the reaction of S8 with [EMIm][OAc], the respective thione is formed via a radical mechanism. Here, we present new results on the kinetics of the formation of the respective imidazole thione (EMImS) via the hexasulfur dianion [S6]2- and the trisulfur radical anion [S3]•-. We can show that [S6]2- is formed first, which dissociates then to [S3]•-. Also, long-term stable radicals occur, which are necessary side products provided in a reaction scheme. During the reaction of [EMIm][OAc] with (SN)x chains, two further products can be identified, one of which is the corresponding imine. The reactions are followed by time-resolved NMR spectroscopic methods that showed the corresponding product distributions and allowed the assignment of the individual signals. In addition, continuous-wave (CW) EPR and UV/vis spectroscopic measurements show the course of the reactions. Another significant difference in both reactions is the formation of a long-term stable radical in the sulfur-IL system, which remains active over 35 days, while for the (SN)x-IL system, we can determine a radical species only with the spin trap 5,5-dimethyl-1-pyrrolin-N-oxide, which indicates the existence of short-living radicals. Since the molecular dynamics are restricted based on the EPR spectra, these radicals must be large.
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Affiliation(s)
- Julian Radicke
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Karsten Busse
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Vanessa Jerschabek
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Haleh Hashemi Haeri
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Muhammad Abu Bakar
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Dariush Hinderberger
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Jörg Kressler
- Department of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
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Hemmeter D, Merlinsky LS, Baraldo LM, Maier F, Williams FJ, Steinrück HP. Exploring the interfacial behavior of ruthenium complexes in ionic liquids: implications for supported ionic liquid phase catalysts. Phys Chem Chem Phys 2024; 26:7602-7610. [PMID: 38363127 DOI: 10.1039/d4cp00247d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
The interaction of metal complexes with ionic liquids, with a particular focus on the stability and surface concentration of the metal centers, is crucial in applications involving catalysts based on supported ionic liquids. In this study, we synthesized the complexes [Ru(tpy)(bpy)Cl][PF6] and [Ru(tpy)(dcb)Cl][PF6] (tpy = 2,2',2''-terpyridine, bpy = 2,2'-bipyridine, dcb = 4,4'-dicarboxy-2,2'-bipyridine) and we prepared solutions using the ionic liquids (ILs) 1-ethyl-3-methylimidazolium acetate [C2C1Im][OAc] and 1-butyl-3-methylimidazolium hexafluorophosphate [C4C1Im][PF6]. The chemical environment of the Ru(II) metal center and the interfacial behavior of the complexes in the different IL solutions were determined using angle-resolved X-ray photoelectron spectroscopy (ARXPS). In [C4C1Im][PF6], [Ru(tpy)(bpy)Cl][PF6] maintains its chemical structure, while in [C2C1Im][OAc], partial changes in the chemical environment of the Ru center are indicated by XPS, likely due to ligand exchange. The presence of carboxylic acid functional groups in the bipyridyl ligand seems to inhibit this ligand exchange. The investigated complexes do not exhibit surface activity but are depleted from the IL/gas interface. These findings hold significance for the design of new supported ionic liquid phase catalysts based on Ru complexes.
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Affiliation(s)
- Daniel Hemmeter
- Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße 3, Erlangen, Germany.
| | - 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
| | - Luis M Baraldo
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie II, 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
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße 3, Erlangen, Germany.
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Aysin RR, Galkin KI. Adaptive carbonyl umpolung involving a carbanionic carbene Breslow intermediate: an alternative mechanism for NHC-mediated organocatalysis. Org Biomol Chem 2023; 21:8702-8707. [PMID: 37867444 DOI: 10.1039/d3ob01195j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Herein, we propose a novel mechanistic model for NHC-mediated carbonyl umpolung which involves the formation of a carbanionic carbene Breslow intermediate (CCBI). We have demonstrated theoretically that this reactive intermediate can be formed by inserting an aldehyde into the C4-H position of an N-aryl-substituted imidazolium-derived NHC via the generation of an H-bonded ditopic carbanionic NHC (dcNHC). Our DFT study on benzoin condensation has revealed that the mechanism of polarity inversion proceeding through the CCBI may be more energetically favorable than the classical mechanism of umpolung that uses the C2 carbene position in NHC. The potential existence of the CCBI highlights the dynamic and adaptive nature of NHC-mediated organocatalysis, particularly in relation to carbonyl umpolung. This finding also sheds light on new pathways in organocatalytic transformations employing the ambident reactivity of NHC, which may be particularly attractive for reactions involving furanic aldehydes and sterically encumbered N-aryl-substituted carbenes.
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Affiliation(s)
- Rinat R Aysin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova, 28, 119991 Moscow, Russia
| | - Konstantin I Galkin
- Bauman Moscow State Technical University, 2nd Baumanskaya ul., 5/1, 105005 Moscow, Russia.
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, ul. Leninsky Prospekt, 47, 119991, Moscow, Russia
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Radicke J, Roos E, Sebastiani D, Brehm M, Kressler J. Lactate‐based ionic liquids as chiral solvents for cellulose. JOURNAL OF POLYMER SCIENCE 2022. [DOI: 10.1002/pol.20220687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Julian Radicke
- Department of Chemistry Martin Luther University Halle–Wittenberg Halle (Saale) Germany
| | - Eliane Roos
- Department of Chemistry Martin Luther University Halle–Wittenberg Halle (Saale) Germany
| | - Daniel Sebastiani
- Department of Chemistry Martin Luther University Halle–Wittenberg Halle (Saale) Germany
| | - Martin Brehm
- Department of Chemistry Martin Luther University Halle–Wittenberg Halle (Saale) Germany
| | - Jörg Kressler
- Department of Chemistry Martin Luther University Halle–Wittenberg Halle (Saale) Germany
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5
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El‐Dash YS, Mahmoud AM, El‐Mosallamy SS, El‐Nassan HB. Electrochemical Synthesis of 5‐Benzylidenebarbiturate Derivatives and Their Application as Colorimetric Cyanide Probe. ChemElectroChem 2022. [DOI: 10.1002/celc.202200954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Yara S. El‐Dash
- Pharmaceutical Organic Chemistry Department Faculty of Pharmacy Cairo University 33 Kasr El-Aini street Cairo 11562 Egypt
| | - Amr M. Mahmoud
- Analytical Chemistry Department Faculty of Pharmacy Cairo University 33 Kasr El-Aini street Cairo 11562 Egypt
| | - Sally S. El‐Mosallamy
- Analytical Chemistry Department Faculty of Pharmacy Cairo University 33 Kasr El-Aini street Cairo 11562 Egypt
| | - Hala B. El‐Nassan
- Pharmaceutical Organic Chemistry Department Faculty of Pharmacy Cairo University 33 Kasr El-Aini street Cairo 11562 Egypt
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Belesov AV, Shkaeva NV, Popov MS, Skrebets TE, Faleva AV, Ul’yanovskii NV, Kosyakov DS. New Insights into the Thermal Stability of 1-Butyl-3-methylimidazolium-Based Ionic Liquids. Int J Mol Sci 2022; 23:ijms231810966. [PMID: 36142873 PMCID: PMC9502186 DOI: 10.3390/ijms231810966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
One of the most promising applications of ionic liquids (ILs) with 1-butyl-3-methylimidazolium (bmim) cation is based on their unique ability to dissolve and fractionate lignocellulosic biomass, allowing for the development of green biorefining technologies. A complete dissolution of lignocellulose requires prolonged treatment at elevated temperatures, which can cause the partial degradation of ILs. In the present study, a combination of various analytical techniques (GC-MS, HPLC-HRMS, 2D-NMR, synchronous thermal analysis) was used for the comprehensive characterization of bmim acetate, chloride, and methyl sulfate degradation products formed at 150 °C during 6- and 24-h thermal treatment. A number of volatile and non-volatile products, including monomeric and dimeric alkyl substituted imidazoles, alcohols, alkyl amines, methyl and butyl acetates, and N-alkylamides, was identified. By thermal lability, ILs can be arranged in the following sequence, coinciding with the decrease in basicity of the anion: [bmim]OAc > [bmim]Cl > [bmim]MeSO4. The accumulation of thermal degradation products in ILs, in turn, affects their physico-chemical properties and thermal stability, and leads to a decrease in the decomposition temperature, a change in the shape of the thermogravimetric curves, and the formation of carbon residue during pyrolysis.
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Osman EO, Mahmoud AM, El-Mosallamy SS, El-Nassan HB. Electrochemical synthesis of tetrahydrobenzo[b]pyran derivatives in deep eutectic solvents. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Grasser MA, Müller U, Ruck M. Low‐Temperature Synthesis of NiSb2, Cu2Sb, InSb and Sb2Te3 Starting from the Elements. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Michael Ruck
- Technische Universität Dresden Faculty of Chemistry and Food Chemistry Helmholtzstr. 10 01069 Dresden GERMANY
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9
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Liu XB, Rong Q, Tan J, Chen C, Hu YL. Recent Advances in Catalytic Oxidation of Organic Sulfides: Applications of Metal–Ionic Liquid Catalytic Systems. Front Chem 2022; 9:798603. [PMID: 35296037 PMCID: PMC8918828 DOI: 10.3389/fchem.2021.798603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/20/2021] [Indexed: 11/13/2022] Open
Abstract
Catalytic oxidation of organic sulfides is of considerable significance in industrial chemistry and fuel industry. Therefore, numerous methods have been developed for the oxidation. Metal-containing ionic liquid-based catalysts can catalyze the selective oxidation reactions and are highly used in chemical processes, which have also been used as effective solvents, reaction media, extractants, and catalysts for the oxidation of organic sulfides including oxidative desulfurization of fuel oil. Recently, much attention is being drawn to the preparation of heterogenous catalysts based on the immobilization of metal- or nonmetal-containing ILs on diverse solid supports, which can be easily separated after the completion reaction and recycled. Therefore, there is still an increasing interest in developing new and efficient catalytic procedures for the oxidation of organic sulfides. In this review, we have outlined the recent advances in catalytic oxidation of organic sulfides including oxidative desulfurization of fuel oil. The versatilities and adaptabilities of metal–ionic liquid catalytic systems in the selective oxidation of sulfides are considered a powerful research field in these transformations.
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Affiliation(s)
- Xiao Bing Liu
- College of Chemistry and Chemical Engineering, Jinggangshan University, Ji’an, China
| | - Qi Rong
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang, China
| | - Jin Tan
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang, China
| | - Chen Chen
- College of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Yu Lin Hu
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang, China
- *Correspondence: Yu Lin Hu,
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10
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Water sorption by ionic liquids: Evidence of a diffusion-controlled sorption process derived from the case study of [BMIm][OAc]. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Stoppelman JP, McDaniel JG. Physics-based, neural network force fields for reactive molecular dynamics: Investigation of carbene formation from [EMIM +][OAc -]. J Chem Phys 2021; 155:104112. [PMID: 34525833 DOI: 10.1063/5.0063187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Reactive molecular dynamics simulations enable a detailed understanding of solvent effects on chemical reaction mechanisms and reaction rates. While classical molecular dynamics using reactive force fields allows significantly longer simulation time scales and larger system sizes compared with ab initio molecular dynamics, constructing reactive force fields is a difficult and complex task. In this work, we describe a general approach following the empirical valence bond framework for constructing ab initio reactive force fields for condensed phase simulations by combining physics-based methods with neural networks (PB/NNs). The physics-based terms ensure the correct asymptotic behavior of electrostatic, polarization, and dispersion interactions and are compatible with existing solvent force fields. NNs are utilized for a versatile description of short-range orbital interactions within the transition state region and accurate rendering of vibrational motion of the reacting complex. We demonstrate our methodology for a simple deprotonation reaction of the 1-ethyl-3-methylimidazolium cation with acetate to form 1-ethyl-3-methylimidazol-2-ylidene and acetic acid. Our PB/NN force field exhibits ∼1 kJ mol-1 mean absolute error accuracy within the transition state region for the gas-phase complex. To characterize the solvent modulation of the reaction profile, we compute potentials of mean force for the gas-phase reaction as well as the reaction within a four-ion cluster and benchmark against ab initio molecular dynamics simulations. We find that the surrounding ionic environment significantly destabilizes the formation of the carbene product, and we show that this effect is accurately captured by the reactive force field. By construction, the PB/NN potential may be directly employed for simulations of other solvents/chemical environments without additional parameterization.
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Affiliation(s)
- John P Stoppelman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
| | - Jesse G McDaniel
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
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12
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Ray A, Saruhan B. Application of Ionic Liquids for Batteries and Supercapacitors. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2942. [PMID: 34072536 PMCID: PMC8197857 DOI: 10.3390/ma14112942] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 11/17/2022]
Abstract
Nowadays, the rapid development and demand of high-performance, lightweight, low cost, portable/wearable electronic devices in electrical vehicles, aerospace, medical systems, etc., strongly motivates researchers towards advanced electrochemical energy storage (EES) devices and technologies. The electrolyte is also one of the most significant components of EES devices, such as batteries and supercapacitors. In addition to rapid ion transport and the stable electrochemical performance of electrolytes, great efforts are required to overcome safety issues due to flammability, leakage and thermal instability. A lot of research has already been completed on solid polymer electrolytes, but they are still lagging for practical application. Over the past few decades, ionic liquids (ILs) as electrolytes have been of considerable interest in Li-ion batteries and supercapacitor applications and could be an important way to make breakthroughs for the next-generation EES systems. The high ionic conductivity, low melting point (lower than 100 °C), wide electrochemical potential window (up to 5-6 V vs. Li+/Li), good thermal stability, non-flammability, low volatility due to cation-anion combinations and the promising self-healing ability of ILs make them superior as "green" solvents for industrial EES applications. In this short review, we try to provide an overview of the recent research on ILs electrolytes, their advantages and challenges for next-generation Li-ion battery and supercapacitor applications.
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Affiliation(s)
| | - Bilge Saruhan
- German Aerospace Center (DLR), Department of High-Temperature and Functional Coatings, Institute of Materials Research, 51147 Cologne, Germany;
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13
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Salvitti C, Bortolami M, Chiarotto I, Troiani A, de Petris G. The Knoevenagel condensation catalysed by ionic liquids: a mass spectrometric insight into the reaction mechanism. NEW J CHEM 2021. [DOI: 10.1039/d1nj03594k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mass spectrometry was used to study the Knoevenagel condensation catalysed by imidazolium-based ionic liquids. Two pathways were highlighted by intercepting two different reaction intermediates: a base-catalysed and a carbene-catalysed mechanism.
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Affiliation(s)
- Chiara Salvitti
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
| | - Martina Bortolami
- Dipartimento di Scienze di Base e Applicate per l’Ingegneria, Sapienza Università di Roma, Via Castro Laurenziano 7, Roma, Italy
| | - Isabella Chiarotto
- Dipartimento di Scienze di Base e Applicate per l’Ingegneria, Sapienza Università di Roma, Via Castro Laurenziano 7, Roma, Italy
| | - Anna Troiani
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
| | - Giulia de Petris
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Roma, Italy
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14
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Salvitti C, Chiarotto I, Pepi F, Troiani A. Charge-Tagged N-Heterocyclic Carbenes (NHCs): Revealing the Hidden Side of NHC-Catalysed Reactions through Electrospray Ionization Mass Spectrometry. Chempluschem 2020; 86:209-223. [PMID: 33252194 DOI: 10.1002/cplu.202000656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/16/2020] [Indexed: 01/08/2023]
Abstract
N-heterocyclic carbenes (NHCs) are key intermediates in a variety of chemical reactions. Owing to their transient nature, the interception and characterization of these reactive species have always been challenging. Similarly, the study of reaction mechanisms in which carbenes act as catalysts is still an active research field. This Minireview describes the contribution of electrospray ionization mass spectrometry (ESI-MS) to the detection of charge-tagged NHCs resulting from the insertion of an ionic group into the molecular scaffold. The use of different mass spectrometric techniques, combined with the charge-tagging strategy, allowed clarification of the involvement of NHCs in archetypal reactions and the study of their intrinsic chemistry.
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Affiliation(s)
- Chiara Salvitti
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, Rome, Italy
| | - Isabella Chiarotto
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria, Sapienza Università di Roma, Via Castro Laurenziano 7, Rome, Italy
| | - Federico Pepi
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, Rome, Italy
| | - Anna Troiani
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, Rome, Italy
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15
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Dzieszkowski K, Barańska I, Mroczyńska K, Słotwiński M, Rafiński Z. Organocatalytic Name Reactions Enabled by NHCs. MATERIALS 2020; 13:ma13163574. [PMID: 32823580 PMCID: PMC7475904 DOI: 10.3390/ma13163574] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 12/20/2022]
Abstract
Giving reactions the names of their discoverers is an extraordinary tradition of organic chemistry. Nowadays, this phenomenon is much rarer, although already named historical reactions are still often developed. This is also true in the case of a broad branch of N-heterocyclic carbenes catalysis. NHCs allow many unique synthetic paths, including commonly known name reactions. This article aims to gather this extensive knowledge and compare historical reactions with current developed processes. Furthermore, this review is a great opportunity to highlight some of the unique applications of these procedures in the total synthesis of biologically active compounds. Hence, this concise article may also be a source of knowledge for scientists just starting their adventure with N-heterocyclic carbene chemistry.
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16
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Galkin KI, Karlinskii BY, Kostyukovich AY, Gordeev EG, Ananikov VP. Ambident Reactivity of Imidazolium Cations as Evidence of the Dynamic Nature of N-Heterocyclic Carbene-Mediated Organocatalysis. Chemistry 2020; 26:8567-8571. [PMID: 32227612 DOI: 10.1002/chem.201905704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/27/2020] [Indexed: 11/10/2022]
Abstract
This work reveals ambident nucleophilic reactivity of imidazolium cations towards carbonyl compounds at the C2 or C4 carbene centers depending on the steric properties of the substrates and reaction conditions. Such an adaptive behavior indicates the dynamic nature of organocatalysis proceeding via a covalent interaction of imidazolium carbenes with carbonyl substrates and can be explained by generation of the H-bonded ditopic carbanionic carbenes.
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Affiliation(s)
- Konstantin I Galkin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991, Moscow, Russia
| | - Bogdan Ya Karlinskii
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991, Moscow, Russia
| | - Alexander Yu Kostyukovich
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991, Moscow, Russia
| | - Evgeniy G Gordeev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991, Moscow, Russia
| | - Valentine P Ananikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991, Moscow, Russia
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17
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Hollóczki O. The Mechanism of N-Heterocyclic Carbene Organocatalysis through a Magnifying Glass. Chemistry 2020; 26:4885-4894. [PMID: 31797448 PMCID: PMC7187225 DOI: 10.1002/chem.201903021] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Indexed: 11/11/2022]
Abstract
The term "N-Heterocyclic carbene organocatalysis" is often invoked in organic synthesis for reactions that are catalyzed by different azolium salts in the presence of bases. Although the mechanism of these reactions is considered today evident, a closer look into the details that have been collected throughout the last century reveals that there are many open questions and even contradictions in the field. Emerging new theoretical and experimental results offer solutions to these problems, because they show that through considering alternative reaction mechanisms a more consistent picture on the catalytic process can be obtained. These novel perspectives will be able to extend the scope of the reactions that we call today N-heterocyclic carbene organocatalysis.
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Affiliation(s)
- Oldamur Hollóczki
- Mulliken Center for Theoretical ChemistryUniversity of BonnBeringstrasse 4+653115BonnGermany
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18
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WO3 and Ionic Liquids: A Synergic Pair for Pollutant Gas Sensing and Desulfurization. METALS 2020. [DOI: 10.3390/met10040475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This review deals with the notable results obtained by the synergy between ionic liquids (ILs) and WO3 in the field of pollutant gas sensing and sulfur removal pretreatment of fuels. Starting from the known characteristics of tungsten trioxide as catalytic material, many authors have proposed the use of ionic liquids in order to both direct WO3 production towards controllable nanostructures (nanorods, nanospheres, etc.) and to modify the metal oxide structure (incorporating ILs) in order to increase the gas adsorption ability and, thus, the catalytic efficiency. Moreover, ionic liquids are able to highly disperse WO3 in composites, thus enhancing the contact surface and the catalytic ability of WO3 in both hydrodesulfurization (HDS) and oxidative desulfurization (ODS) of liquid fuels. In particular, the use of ILs in composite synthesis can direct the hydrogenation process (HDS) towards sulfur compounds rather than towards olefins, thus preserving the octane number of the fuel while highly reducing the sulfur content and, thus, the possibility of air pollution with sulfur oxides. A similar performance enhancement was obtained in ODS, where the high dispersion of WO3 (due to the use of ILs during the synthesis) allows for noteworthy results at very low temperatures (50 °C).
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Pandolfi F, Chiarotto I, Mattiello L, Petrucci R, Feroci M. Two Different Selective Ways in the Deprotonation of β‐Bromopropionanilides: β‐Lactams or Acrylanilides Formation. ChemistrySelect 2019. [DOI: 10.1002/slct.201902841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Fabiana Pandolfi
- Department of Scienze di Base e Applicate per l'Ingegneria (SBAI)Sapienza University of Rome via del Castro Laurenziano, 7 00161 Roma Italy
| | - Isabella Chiarotto
- Department of Scienze di Base e Applicate per l'Ingegneria (SBAI)Sapienza University of Rome via del Castro Laurenziano, 7 00161 Roma Italy
| | - Leonardo Mattiello
- Department of Scienze di Base e Applicate per l'Ingegneria (SBAI)Sapienza University of Rome via del Castro Laurenziano, 7 00161 Roma Italy
| | - Rita Petrucci
- Department of Scienze di Base e Applicate per l'Ingegneria (SBAI)Sapienza University of Rome via del Castro Laurenziano, 7 00161 Roma Italy
| | - Marta Feroci
- Department of Scienze di Base e Applicate per l'Ingegneria (SBAI)Sapienza University of Rome via del Castro Laurenziano, 7 00161 Roma Italy
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Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration. Polymers (Basel) 2019; 11:polym11121917. [PMID: 31766402 PMCID: PMC6960809 DOI: 10.3390/polym11121917] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 10/31/2019] [Accepted: 11/03/2019] [Indexed: 11/17/2022] Open
Abstract
This review is focused on assessment of solvents for cellulose dissolution and the mechanism of regeneration of the dissolved biopolymer. The solvents of interest are imidazole-based ionic liquids, quaternary ammonium electrolytes, salts of super-bases, and their binary mixtures with molecular solvents. We briefly discuss the mechanism of cellulose dissolution and address the strategies for assessing solvent efficiency, as inferred from its physico-chemical properties. In addition to the favorable effect of lower cellulose solution rheology, microscopic solvent/solution properties, including empirical polarity, Lewis acidity, Lewis basicity, and dipolarity/polarizability are determinants of cellulose dissolution. We discuss how these microscopic properties are calculated from the UV-Vis spectra of solvatochromic probes, and their use to explain the observed solvent efficiency order. We dwell briefly on use of other techniques, in particular NMR and theoretical calculations for the same purpose. Once dissolved, cellulose is either regenerated in different physical shapes, or derivatized under homogeneous conditions. We discuss the mechanism of, and the steps involved in cellulose regeneration, via formation of mini-sheets, association into “mini-crystals”, and convergence into larger crystalline and amorphous regions. We discuss the use of different techniques, including FTIR, X-ray diffraction, and theoretical calculations to probe the forces involved in cellulose regeneration.
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Filippov A, Antzutkin ON, Shah FU. Rapid carbene formation increases ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates. Phys Chem Chem Phys 2019; 21:22531-22538. [PMID: 31588443 DOI: 10.1039/c9cp04504j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1-Ethyl-3-methyl-imidazolium acetate ([EMIM][OAc]) is one of the most widely used ionic liquids for various applications. This study is focussed on the chemical stability of [EMIM][OAc] on the surfaces of polar glass plates. 1H and 13C NMR spectroscopy and NMR diffusometry of [EMIM][OAc] IL confined between glass plates with a specific surface area 105-106 m-1 are thoroughly investigated. A rapid and spontaneous reaction took place on the surfaces of glass plates leading to the formation of neutral chemical moieties as evident by the appearance of new signals in the 1H NMR spectra. These new products are assigned as N-heterocyclic carbene (NHC) and acetic acid. These neutral chemical moieties have significantly increased the ion diffusivity by dissociation of the cation and the anion in [EMIM][OAc] IL. The yield and rate of formation of NHC and acetic acid are found to increase with the increasing surface area of polar glass plates and the time of contact between the IL and glass surfaces. Based on NMR spectroscopy, a dissociative reaction mechanism is proposed for the formation of free NHC in the neat [EMIM][OAc] IL.
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Affiliation(s)
- Andrei Filippov
- Chemistry of Interfaces, Luleå University of Technology, SE-97187 Luleå, Sweden. and Kazan State Medical University, 420012 Kazan, Russia
| | - Oleg N Antzutkin
- Chemistry of Interfaces, Luleå University of Technology, SE-97187 Luleå, Sweden. and Department of Physics, Warwick University, Coventry CV4 7AL, UK
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, SE-97187 Luleå, Sweden.
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Mezzetta A, Poderelli L, D'Andrea F, Pomelli CS, Chiappe C, Guazzelli L. Unexpected Intrinsic Lability of Thiol-Functionalized Carboxylate Imidazolium Ionic Liquids. Molecules 2019; 24:E3571. [PMID: 31623295 PMCID: PMC6804084 DOI: 10.3390/molecules24193571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/26/2019] [Accepted: 09/30/2019] [Indexed: 11/16/2022] Open
Abstract
New thiol-functionalized carboxylate ionic liquids (ILs), varying both for the cation and for the anion structures, have been prepared as new potential redox switching systems by reacting either 3-mercapto propionic acid (3-MPA) or N-acetyl-cysteine (NAC) with commercially available methyl carbonate ILs. Different ratios of thiol/disulfide ILs were obtained depending both on the acid employed in the neutralization reaction and on the reaction conditions used. Surprisingly, the imidazolium ILs displayed limited thermal stability which resulted in the formation of an imidazole 2-thione and a new sulfide ionic liquid. Conversely, the formation of the imidazole 2-thione was not observed when phosphonium disulfide ILs were heated, thus confirming the involvement of the imidazolium ring in an unexpected side reaction. An insight into the mechanism of the decomposition has been provided by means of DFT calculations.
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Affiliation(s)
- Andrea Mezzetta
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy.
| | - Lorenzo Poderelli
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy.
| | - Felicia D'Andrea
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy.
| | | | - Cinzia Chiappe
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy.
| | - Lorenzo Guazzelli
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy.
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