Molecular design of ambipolar redox-active open-shell molecules: Principles and implementations

Sentyurin, Vyacheslav V.; Levitskiy, Oleg A.; Magdesieva, Tatiana V.

doi:10.1016/j.coelec.2020.05.006

Cited by 21 publications

(34 citation statements)

References 56 publications

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“…Nevertheless, the insufficient stability of aminoxyl anions limits their applications to be used only as a cathodic material [32] . Some neutral radicals, however, are stabilized in all three oxidation states and have revealed their potential in BRM applications [17,32a] . In this section, we will highlight these radicals, particularly the methods applied in improving their stability and other critical physicochemical properties.…”

Section: Strategies In Developing Bipolar Redox‐active Moleculesmentioning

confidence: 99%

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Bipolar Redox‐Active Molecules in Non‐Aqueous Organic Redox Flow Batteries: Status and Challenges

Case

2021

ChemElectroChem

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Section: Strategies In Developing Bipolar Redox‐active Moleculesmentioning

confidence: 99%

“…With the rapid development of O−NRFBs, the past decade has seen a surge of interest in developing SRFBs to address active‐species crossover [32a,43a,58] . Aside from preparing BRMs, one alternative strategy is utilizing a mixture of catholyte and anolyte.…”

Section: Strategies In Developing Bipolar Redox‐active Moleculesmentioning

confidence: 99%

Bipolar Redox‐Active Molecules in Non‐Aqueous Organic Redox Flow Batteries: Status and Challenges

Case

2021

ChemElectroChem

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“…The solid was washed extensively with Et 2 O and air-dried yielding [3a + ][BF 4 ] as a solid (128 mg, 0.35 mmol, 97%). 1 H NMR (600 MHz, 25 °C, CD 3 CN): δ 8.81-8.78 (m, 2H), 8.66-8.63 (m, 1H), 8.43-8.41 (dt, 1H), 8.03-7.98 (m, 1H), 7.92-7.89 (d, 4H); 19 F NMR (565 MHz, 25 °C, CD 3 CN) δ -75.09 (s, 3F, CF 3 ), -152.0 (4F, BF 4 ); 13…”

Section: Synthesis Of 1-phenyl-3-(trifluoromethyl)benzo[e]-[124]triazin-1-ium Tetrafluoroborate ([3a + ][Bf4])mentioning

confidence: 99%

“…Young valve and shaken for 2 hours under inert atmosphere during which the color turned orange. 1 H NMR (600 MHz, 25 °C, CD 3 CN): δ 7.27-7.25 (m, 2H), 7.18-7.13 (mz, 2H), 6.74-6.71 (tt, 1H), 6.49-6.46 (td, 1H), 6.36-6.31 (m, 2H), 6.12-6.10 (dd, 1H); 19 F NMR (565 MHz, 25 °C, CD 3 CN) δ -72.27; 13 C NMR (151 MHz, 25 °C, CD 3 CN): δ 159.4 (q, ipso-C, C-CF3, 2 J( 19 F, 13 C) = 29 Hz), 150.8 (ipso-C), 148.2 (ipso-C), 136.4 (ipso-C), 129.3 (CH), 122.1 (q, CF3, 1 J( 19 F, 13 C) = 275 Hz), 124.7 (CH), 120.5 (CH), 119.8 (CH), 118.6 (CH), 117.3 (CH), 115.0 (CH).…”

Section: Synthesis Of Sodium 1-phenyl-3-(trifluoromethyl)benzo[e][124]triazin-4-ide ([3a -][Na]mentioning

confidence: 99%

“…9,11 In addition to closed-shell compounds, 12 several classes of stable organic radicals are known to possess bipolar electrochemistry and are thus of potential interest as battery materials. 13 Examples of bipolar organic radicals that have been explored to date include nitronyl nitroxides 14 and verdazyls, 15 but these systems show relatively rapid degradation 16 in the charged state and high capacity retention is yet to be achieved. Here we show that 1,2,4benzotriazin-4-yl radicals (commonly known as Blatter radicals) 17,18 combine the tunable redox-potentials and high stability in all relevant redox states necessary for application as redox active components in RFBs.…”

Section: Introductionmentioning

confidence: 99%

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Blatter Radicals as Bipolar Materials for Symmetric Redox-Flow Batteries

Steen

Nuismer

Eiva

et al. 2021

Preprint

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Redox-active organic molecules are promising charge-storage materials for redox-flow batteries (RFBs), but material crossover between posolyte/negolyte and chemical degradation are limiting factors in the performance of all-organic RFBs. We demonstrate that the bipolar electrochemistry of 1,2,4-benzotriazin-4-yl (Blatter) radicals allows construction of batteries with symmetric electrolyte composition. Cyclic voltammetry shows that these radicals retain reversible bipolar electrochemistry also in the presence of water. The redox potentials of derivatives with a C(3)-CF3 substituent are least affected by water and, moreover, these compounds show >90% capacity retention after charge/discharge cycling in a static H-cell for seven days (ca. 100 cycles). Testing these materials in a flow regime at 0.1 M concentration of active material confirmed the high cycling stability under conditions relevant for RFB operation, and demonstrated that polarity inversion in a symmetric flow battery may be used to rebalance the cell. Chemical synthesis provides insight in the nature of the charged species by spectroscopy and (for the oxidized state) X-ray crystallography. The stability of these compounds in all three states of charge highlights the potential for application in symmetric organic redox-flow batteries.

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Geometrical and Electronic Structure of Cation Radical Species of Tetraarylanthraquinodimethane: An Intermediate for Unique Electrochromic Behavior

Ishigaki

Fukagawa

Sugawara

et al. 2022

Chemistry An Asian Journal

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Two tetraarylanthraquinodimethane (Ar 4 AQD) derivatives having two different aryl groups (aminophenyl and methoxyphenyl) were prepared by sequential dibromomethylation and Suzuki-coupling reactions. X-ray analyses showed that they adopt a folded structure in the neutral state whereas the corresponding dications have a planar anthracene ring, to which diarylmethylium units are perpendicularly attached. Different from Ar 4 AQD having the same substituents that undergoes facile two-electron transfer during interconversion with the dicationic state, the intermediary cation radical becomes long-lived in the newly prepared unsymmetric derivatives. The geometric and electronic structures of the open-shell intermediates were elucidated through electrochemical and theoretical investigation, with revealing that the cation radicals adopt the twisted geometry like dications. Upon electrolyses of the dications, the twisted cation radicals were involved in the electrochromism whereas their steady-state concentration is negligible in the oxidation process, thus realizing unique tricolor electrochromic behavior with a hysteretic pattern of color change (colorless -> purple -> blue -> colorless).

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Molecular design of ambipolar redox-active open-shell molecules: Principles and implementations

Cited by 21 publications

References 56 publications

Bipolar Redox‐Active Molecules in Non‐Aqueous Organic Redox Flow Batteries: Status and Challenges

Bipolar Redox‐Active Molecules in Non‐Aqueous Organic Redox Flow Batteries: Status and Challenges

Blatter Radicals as Bipolar Materials for Symmetric Redox-Flow Batteries

Geometrical and Electronic Structure of Cation Radical Species of Tetraarylanthraquinodimethane: An Intermediate for Unique Electrochromic Behavior

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