Stable organic radicals and their untapped potential in ionic liquids
Theo A. Ellingsen
A , Natasha Hoffmann B , Wesley J. Olivier A , Stuart C. Thickett A , Debbie S. Silvester B and Rebecca O. Fuller A *
+ Author Affiliations
- Author Affiliations
A School of Natural Sciences – Chemistry, University of Tasmania, Hobart, Tas., Australia.
B School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Australian Journal of Chemistry 75(11) 893-898 https://doi.org/10.1071/CH22126
Submitted: 2 June 2022 Accepted: 26 July 2022 Published: 19 August 2022
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)
Abstract
Stable organic radicals have an open shell structure that makes them suitable for use in a diverse set of applications. Specifically, it is the reversible one-electron redox behaviour that makes these species suitable for energy storage and in molecular electronics. Maintaining chemical stability, low redox potential and charge transfer capabilities, are key to the further development of these materials. To date, researchers have largely focused on the the preparation of new molecules with improved redox capabilities for use in traditional solvents. More recently exploration into the use of ionic liquids to stabilise charged species and reduce side reactions has shown promise. Computational and preliminary experimental studies have explored the impact of ionic liquids on radical stabilisation, and notable improvements have been observed for nitroxide-based materials when traditional solvents are replaced by ionic liquids. However, these gains require significant refinement based on the identity of the radical species and the ionic liquid. In this highlight, we focus on the current state of using ionic liquids as solvents to stabilise organic radicals and suggestions on the future direction of the field.
Keywords: Blatter, electrochemistry, ionic liquids, nitroxide, polymer composite, radicals, redox active material, verdazyl.
References
[1] D Griller, KU Ingold, Persistent carbon-centered radicals. Acc Chem Res 1976, 9, 13.| Persistent carbon-centered radicals.Crossref | GoogleScholarGoogle Scholar |
[2] M Gomberg, An instance of trivalent carbon: triphenylmethyl. J Am Chem Soc 1900, 22, 757.
| An instance of trivalent carbon: triphenylmethyl.Crossref | GoogleScholarGoogle Scholar |
[3] RG Hicks, What’s new in stable radical chemistry? Org Biomol Chem 2007, 5, 1321.
| What’s new in stable radical chemistry?Crossref | GoogleScholarGoogle Scholar |
[4] B Tang, J Zhao, J-F Xu, X Zhang, Tuning the stability of organic radicals: from covalent approaches to non-covalent approaches. Chem Sci 2020, 11, 1192.
| Tuning the stability of organic radicals: from covalent approaches to non-covalent approaches.Crossref | GoogleScholarGoogle Scholar |
[5] Z Yang, M Bridges, MT Lerch, C Altenbach, WL Hubbell, Saturation recovery EPR and nitroxide spin labeling for exploring structure and dynamics in proteins. Methods Enzymol 2015, 564, 3.
| Saturation recovery EPR and nitroxide spin labeling for exploring structure and dynamics in proteins.Crossref | GoogleScholarGoogle Scholar |
[6] RO Fuller, MR Taylor, M Duggin, AC Bissember, AJ Canty, MM Judd, N Cox, SA Moggach, GF Turner, Enhanced synthesis of oxo-verdazyl radicals bearing sterically-and electronically-diverse C3-substituents. Org Biomol Chem 2021, 19, 10120.
| Enhanced synthesis of oxo-verdazyl radicals bearing sterically-and electronically-diverse C3-substituents.Crossref | GoogleScholarGoogle Scholar |
[7] JB Gilroy, SDJ McKinnon, BD Koivisto, RG Hicks, Electrochemical studies of verdazyl radicals. Org Lett 2007, 9, 4837.
| Electrochemical studies of verdazyl radicals.Crossref | GoogleScholarGoogle Scholar |
[8] ZX Chen, Y Li, F Huang, Persistent and stable organic radicals: design, synthesis, and applications. Chem 2021, 7, 288.
| Persistent and stable organic radicals: design, synthesis, and applications.Crossref | GoogleScholarGoogle Scholar |
[9] I Ratera, J Veciana, Playing with organic radicals as building blocks for functional molecular materials. Chem Soc Rev 2012, 41, 303.
| Playing with organic radicals as building blocks for functional molecular materials.Crossref | GoogleScholarGoogle Scholar |
[10] M Winter, B Barnett, K Xu, Before Li ion batteries. Chem Rev 2018, 118, 11433.
| Before Li ion batteries.Crossref | GoogleScholarGoogle Scholar |
[11] K-A Hansen, JP Blinco, Nitroxide radical polymers – a versatile material class for high-tech applications. Polym Chem 2018, 9, 1479.
| Nitroxide radical polymers – a versatile material class for high-tech applications.Crossref | GoogleScholarGoogle Scholar |
[12] MB Casu, Nanoscale studies of organic radicals: surface, interface, and spinterface. Acc Chem Res 2018, 51, 753.
| Nanoscale studies of organic radicals: surface, interface, and spinterface.Crossref | GoogleScholarGoogle Scholar |
[13] T Janoschka, N Martin, U Martin, C Friebe, S Morgenstern, H Hiller, MD Hager, US Schubert, An aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials. Nature 2015, 527, 78.
| An aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials.Crossref | GoogleScholarGoogle Scholar |
[14] S Muench, A Wild, C Friebe, B Häupler, T Janoschka, US Schubert, Polymer-based organic batteries. Chem Rev 2016, 116, 9438.
| Polymer-based organic batteries.Crossref | GoogleScholarGoogle Scholar |
[15] C Karlsson, T Suga, H Nishide, Quantifying TEMPO redox polymer charge transport toward the organic radical battery. ACS Appl Mater Interfaces 2017, 9, 10692.
| Quantifying TEMPO redox polymer charge transport toward the organic radical battery.Crossref | GoogleScholarGoogle Scholar |
[16] Y Chen, C Wang, Designing high performance organic batteries. Acc Chem Res 2020, 53, 2636.
| Designing high performance organic batteries.Crossref | GoogleScholarGoogle Scholar |
[17] K Nakahara, S Iwasa, M Satoh, Y Morioka, J Iriyama, M Suguro, E Hasegawa, Rechargeable batteries with organic radical cathodes. Chem Phys Lett 2002, 359, 351.
| Rechargeable batteries with organic radical cathodes.Crossref | GoogleScholarGoogle Scholar |
[18] L Bugnon, CJH Morton, P Novak, J Vetter, P Nesvadba, Synthesis of poly(4-methacryloyloxy-TEMPO) via group-transfer polymerization and its evaluation in organic radical battery. Chem Mater 2007, 19, 2910.
| Synthesis of poly(4-methacryloyloxy-TEMPO) via group-transfer polymerization and its evaluation in organic radical battery.Crossref | GoogleScholarGoogle Scholar |
[19] A Wild, M Strumpf, B Häupler, MD Hager, US Schubert, All-organic battery composed of thianthrene- and TCAQ-based polymers. Adv Energy Mater 2017, 7, 1601415.
| All-organic battery composed of thianthrene- and TCAQ-based polymers.Crossref | GoogleScholarGoogle Scholar |
[20] T Janoschka, MD Hager, US Schubert, Powering up the future: radical polymers for battery applications. Adv Mater 2012, 24, 6397.
| Powering up the future: radical polymers for battery applications.Crossref | GoogleScholarGoogle Scholar |
[21] TP Nguyen, AD Easley, N Kang, S Khan, S-M Lim, YH Rezenom, S Wang, DK Tran, J Fan, RA Letteri, X He, L Su, C-H Yu, JL Lutkenhaus, KL Wooley, Polypeptide organic radical batteries. Nature 2021, 593, 61.
| Polypeptide organic radical batteries.Crossref | GoogleScholarGoogle Scholar |
[22] GL Soloveichik, Flow batteries: current status and trends. Chem Rev 2015, 115, 11533.
| Flow batteries: current status and trends.Crossref | GoogleScholarGoogle Scholar |
[23] J Cao, J Tian, J Xu, Y Wang, Organic flow batteries: recent progress and perspectives. Energy Fuels 2020, 34, 13384.
| Organic flow batteries: recent progress and perspectives.Crossref | GoogleScholarGoogle Scholar |
[24] M Li, J Case, SD Minteer, Bipolar redox-active molecules in non-aqueous organic redox flow batteries: status and challenges. ChemElectroChem 2021, 8, 1215.
| Bipolar redox-active molecules in non-aqueous organic redox flow batteries: status and challenges.Crossref | GoogleScholarGoogle Scholar |
[25] L Wylie, T Blesch, R Freeman, K Hatakeyama-Sato, K Oyaizu, M Yoshizawa-Fujita, EI Izgorodina, Reversible reduction of the TEMPO radical: one step closer to an all-organic redox flow battery. ACS Sustain Chem Eng 2020, 8, 17988.
| Reversible reduction of the TEMPO radical: one step closer to an all-organic redox flow battery.Crossref | GoogleScholarGoogle Scholar |
[26] JP Blinco, JL Hodgson, BJ Morrow, JR Walker, GD Will, ML Coote, SE Bottle, Experimental and theoretical studies of the redox potentials of cyclic nitroxides. J Org Chem 2008, 73, 6763.
| Experimental and theoretical studies of the redox potentials of cyclic nitroxides.Crossref | GoogleScholarGoogle Scholar |
[27] N Dotti, E Heintze, M Slota, R Hübner, F Wang, J Nuss, M Dressel, L Bogani, Conduction mechanism of nitronyl–nitroxide molecular magnetic compounds. Phys Rev B 2016, 93, 165201.
| Conduction mechanism of nitronyl–nitroxide molecular magnetic compounds.Crossref | GoogleScholarGoogle Scholar |
[28] T Suga, Y-J Pu, S Kasatori, H Nishide, Cathode- and anode-active poly(nitroxylstyrene)s for rechargeable batteries: p- and n-type redox switching via substituent effects. Macromolecules 2007, 40, 3167.
| Cathode- and anode-active poly(nitroxylstyrene)s for rechargeable batteries: p- and n-type redox switching via substituent effects.Crossref | GoogleScholarGoogle Scholar |
[29] L Wylie, K Hakatayama-Sato, C Go, K Oyaizu, EI Izgorodina, Electrochemical characterization and thermodynamic analysis of TEMPO derivatives in ionic liquids. Phys Chem Chem Phys 2021, 23, 10205.
| Electrochemical characterization and thermodynamic analysis of TEMPO derivatives in ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[30] P Wasserscheid, W Keim, Ionic liquids – new “solutions” for transition metal catalysis. Angew Chem Int Ed 2000, 39, 3772.
| Ionic liquids – new “solutions” for transition metal catalysis.Crossref | GoogleScholarGoogle Scholar |
[31] M Armand, F Endres, DR MacFarlane, H Ohno, B Scrosati, Ionic-liquid materials for the electrochemical challenges of the future. Nat Mater 2009, 8, 621.
| Ionic-liquid materials for the electrochemical challenges of the future.Crossref | GoogleScholarGoogle Scholar |
[32] M Watanabe, ML Thomas, S Zhang, K Ueno, T Yasuda, K Dokko, Application of ionic liquids to energy storage and conversion materials and devices. Chem Rev 2017, 117, 7190.
| Application of ionic liquids to energy storage and conversion materials and devices.Crossref | GoogleScholarGoogle Scholar |
[33] J Zhang, B Sun, Y Zhao, A Tkacheva, Z Liu, K Yan, X Guo, AM McDonagh, D Shanmukaraj, C Wang, T Rojo, M Armand, Z Peng, G Wang, A versatile functionalized ionic liquid to boost the solution-mediated performances of lithium-oxygen batteries. Nat Commun 2019, 10, 602.
| A versatile functionalized ionic liquid to boost the solution-mediated performances of lithium-oxygen batteries.Crossref | GoogleScholarGoogle Scholar |
[34] J Lee, C Caporale, AJ McKinley, RO Fuller, DS Silvester, Electrochemical properties of a verdazyl radical in room temperature ionic liquids. Aust J Chem 2020, 73, 1001.
| Electrochemical properties of a verdazyl radical in room temperature ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[35] VM Ortiz-Martínez, L Gómez-Coma, G Pérez, A Ortiz, I Ortiz, The roles of ionic liquids as new electrolytes in redox flow batteries. Sep Purif Technol 2020, 252, 117436.
| The roles of ionic liquids as new electrolytes in redox flow batteries.Crossref | GoogleScholarGoogle Scholar |
[36] F Endres, S Zein El Abedin, Air and water stable ionic liquids in physical chemistry. Phys Chem Chem Phys 2006, 8, 2101.
| Air and water stable ionic liquids in physical chemistry.Crossref | GoogleScholarGoogle Scholar |
[37] P Gerlach, A Balducci, A critical analysis about the underestimated role of the electrolyte in batteries based on organic materials. ChemElectroChem 2020, 7, 2364.
| A critical analysis about the underestimated role of the electrolyte in batteries based on organic materials.Crossref | GoogleScholarGoogle Scholar |
[38] LE Barrosse-Antle, AM Bond, RG Compton, AM O’Mahony, EI Rogers, DS Silvester, Voltammetry in room temperature ionic liquids: comparisons and contrasts with conventional electrochemical solvents. Chem Asian J 2010, 5, 202.
| Voltammetry in room temperature ionic liquids: comparisons and contrasts with conventional electrochemical solvents.Crossref | GoogleScholarGoogle Scholar |
[39] W Kunz, K Häckl, The hype with ionic liquids as solvents. Chem Phys Lett 2016, 661, 6.
| The hype with ionic liquids as solvents.Crossref | GoogleScholarGoogle Scholar |
[40] RG Evans, AJ Wain, C Hardacre, RG Compton, An electrochemical and ESR spectroscopic study on the molecular dynamics of TEMPO in room temperature ionic liquid solvents. ChemPhysChem 2005, 6, 1035.
| An electrochemical and ESR spectroscopic study on the molecular dynamics of TEMPO in room temperature ionic liquid solvents.Crossref | GoogleScholarGoogle Scholar |
[41] Y Maruyama, K Nagamine, A Nomura, S Iwasa, S Tokito, Electrochemical characterization of TEMPO radical in ionic liquids. Electrochemistry 2020, 88, 34.
| Electrochemical characterization of TEMPO radical in ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[42] V Strehmel, Radicals in ionic liquids. ChemPhysChem 2012, 13, 1649.
| Radicals in ionic liquids.Crossref | GoogleScholarGoogle Scholar |
[43] G Gryn’ova, ML Coote, Origin and scope of long-range stabilizing interactions and associated SOMO–HOMO conversion in distonic radical anions. J Am Chem Soc 2013, 135, 15392.
| Origin and scope of long-range stabilizing interactions and associated SOMO–HOMO conversion in distonic radical anions.Crossref | GoogleScholarGoogle Scholar |
[44] L Wylie, ZL Seeger, AN Hancock, EI Izgorodina, Increased stability of nitroxide radicals in ionic liquids: more than a viscosity effect. Phys Chem Chem Phys 2019, 21, 2882.
| Increased stability of nitroxide radicals in ionic liquids: more than a viscosity effect.Crossref | GoogleScholarGoogle Scholar |
[45] L Wylie, K Oyaizu, A Karton, M Yoshizawa-Fujita, EI Izgorodina, Toward improved performance of all-organic nitroxide radical batteries with ionic liquids: a theoretical perspective. ACS Sustain Chem Eng 2019, 7, 5367.
| Toward improved performance of all-organic nitroxide radical batteries with ionic liquids: a theoretical perspective.Crossref | GoogleScholarGoogle Scholar |
[46] S Zhang, G Wang, Y Lu, W Zhu, C Peng, H Liu, The interactions between imidazolium-based ionic liquids and stable nitroxide radical species: a theoretical study. J Phys Chem A 2016, 120, 6089.
| The interactions between imidazolium-based ionic liquids and stable nitroxide radical species: a theoretical study.Crossref | GoogleScholarGoogle Scholar |
[47] B Gizatullin, C Mattea, S Stapf, Molecular dynamics in ionic liquid/radical systems. J Phys Chem B 2021, 125, 4850.
| Molecular dynamics in ionic liquid/radical systems.Crossref | GoogleScholarGoogle Scholar |
[48] TM Ismail, N Mohan, PK Sajith, Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals. New J Chem 2021, 45, 3866.
| Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals.Crossref | GoogleScholarGoogle Scholar |
[49] Z Chang, D Henkensmeier, R Chen, Shifting redox potential of nitroxyl radical by introducing an imidazolium substituent and its use in aqueous flow batteries. J Power Sources 2019, 418, 11.
| Shifting redox potential of nitroxyl radical by introducing an imidazolium substituent and its use in aqueous flow batteries.Crossref | GoogleScholarGoogle Scholar |
[50] T Hagemann, J Winsberg, M Grube, I Nischang, T Janoschka, N Martin, MD Hager, US Schubert, An aqueous all-organic redox-flow battery employing a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-containing polymer as catholyte and dimethyl viologen dichloride as anolyte. J Power Sources 2018, 378, 546.
| An aqueous all-organic redox-flow battery employing a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-containing polymer as catholyte and dimethyl viologen dichloride as anolyte.Crossref | GoogleScholarGoogle Scholar |
[51] M Aqil, F Ouhib, A Aqil, A El Idrissi, C Detrembleur, C Jérôme, Polymer ionic liquid bearing radicals as an active material for organic batteries with ultrafast charge-discharge rate. Eur Polym J 2018, 106, 242.
| Polymer ionic liquid bearing radicals as an active material for organic batteries with ultrafast charge-discharge rate.Crossref | GoogleScholarGoogle Scholar |
[52] MY Ivanov, OA Krumkacheva, SA Dzuba, MV Fedin, Microscopic rigidity and heterogeneity of ionic liquids probed by stochastic molecular librations of the dissolved nitroxides. Phys Chem Chem Phys 2017, 19, 26158.
| Microscopic rigidity and heterogeneity of ionic liquids probed by stochastic molecular librations of the dissolved nitroxides.Crossref | GoogleScholarGoogle Scholar |
[53] Y Tan, NC Casetti, BW Boudouris, BM Savoie, Molecular design features for charge transport in nonconjugated radical polymers. J Am Chem Soc 2021, 143, 11994.
| Molecular design features for charge transport in nonconjugated radical polymers.Crossref | GoogleScholarGoogle Scholar |
[54] VJ Kumar, J-Z Wu, M Judd, E Rousset, M Korb, SA Moggach, N Cox, PJ Low, The syntheses, structures and spectroelectrochemical properties of 6-oxo-verdazyl derivatives bearing surface anchoring groups. J Mater Chem C 2022, 10, 1896.
| The syntheses, structures and spectroelectrochemical properties of 6-oxo-verdazyl derivatives bearing surface anchoring groups.Crossref | GoogleScholarGoogle Scholar |
[55] JT Price, JA Paquette, CS Harrison, R Bauld, G Fanchini, JB Gilroy, 6-Oxoverdazyl radical polymers with tunable electrochemical properties. Polym Chem 2014, 5, 5223.
| 6-Oxoverdazyl radical polymers with tunable electrochemical properties.Crossref | GoogleScholarGoogle Scholar |
[56] F Magnan, JS Dhindsa, M Anghel, P Bazylewski, G Fanchini, JB Gilroy, A divergent strategy for the synthesis of redox-active verdazyl radical polymers. Polym Chem 2021, 12, 2786.
| A divergent strategy for the synthesis of redox-active verdazyl radical polymers.Crossref | GoogleScholarGoogle Scholar |
[57] JA Grant, Z Lu, DE Tucker, BM Hockin, DS Yufit, MA Fox, R Kataky, V Chechik, AC O’Donoghue, New Blatter-type radicals from a bench-stable carbene. Nat Commun 2017, 8, 15088.
| New Blatter-type radicals from a bench-stable carbene.Crossref | GoogleScholarGoogle Scholar |
[58] A Saal, C Friebe, US Schubert, Polymeric Blatter's radical via CuAAC and ROMP. Macromol Chem Phys 2021, 222, 2100194.
| Polymeric Blatter's radical via CuAAC and ROMP.Crossref | GoogleScholarGoogle Scholar |
[59] FJM Rogers, PL Norcott, ML Coote, Recent advances in the chemistry of benzo[e][1,2,4]triazinyl radicals. Org Biomol Chem 2020, 18, 8255.
| Recent advances in the chemistry of benzo[e][1,2,4]triazinyl radicals.Crossref | GoogleScholarGoogle Scholar |
[60] AC Savva, SI Mirallai, GA Zissimou, AA Berezin, M Demetriades, A Kourtellaris, CP Constantinides, C Nicolaides, T Trypiniotis, PA Koutentis, Preparation of Blatter radicals via Aza-Wittig chemistry: the reaction of N-aryliminophosphoranes with 1-(Het)aroyl-2-aryldiazenes. J Org Chem 2017, 82, 7564.
| Preparation of Blatter radicals via Aza-Wittig chemistry: the reaction of N-aryliminophosphoranes with 1-(Het)aroyl-2-aryldiazenes.Crossref | GoogleScholarGoogle Scholar |
[61] AA Berezin, G Zissimou, CP Constantinides, Y Beldjoudi, JM Rawson, PA Koutentis, Route to benzo- and pyrido-fused 1,2,4-triazinyl radicals via N′-(Het)aryl-N′-[2-nitro(het)aryl]hydrazides. J Org Chem 2014, 79, 314.
| Route to benzo- and pyrido-fused 1,2,4-triazinyl radicals via N′-(Het)aryl-N′-[2-nitro(het)aryl]hydrazides.Crossref | GoogleScholarGoogle Scholar |
