Multifunctional organic molecules and materials derived from (c 1-c 5) alkyl imidazole 2,2,6,6-tetramethylpiperidine-1-oxyl

Abstract

The invention relates to compounds of general formula (1) : in which The invention also relates to specific applications of these compounds associated with their electrochemical and / or catalytic properties.

Description

[0001] DESCRIPTION

[0002] TITLE: MULTIFUNCTIONAL ORGANIC MOLECULES AND MATERIALS DERIVED FROM ALKYL (C1-C5) IMIDAZOLE 2,2,6,6-TETRAMETHYLPIPERIDINE-l-OXYL

[0003] FIELD OF INVENTION

[0004] The invention relates to multifunctional electroactive organic compounds derived from alkyl (C1-C5) imidazole 2,2,6,6-tetramethylpiperidine-l-oxyls and capable of constituting electroactive protic ionic liquids, electroactive zwitterions, and bicationic electroactives; compounds of this family can therefore give rise to a wide variety of applications, for example, but not limited to, electrochemical, bioelectrochemical, energy storage applications (such as in supercapacitors, organic batteries and redox flow batteries) or as organic catalysts for the conversion of biomass into chemicals of industrial interest or as enzymatic cofactors.

[0005] STATE OF THE ART

[0006] Organic radicals are molecular entities possessing an unpaired electron. Due to their electronic structure, organic radicals possess specific magnetic, optical, and redox properties. These properties can be applied to numerous functional materials, such as spin probes, magnetic materials, optoelectronic materials, and electroactive materials.

[0007] Acid-base equilibrium is one of the most widespread reactions in chemistry and plays a vital role in both basic research and technological applications. In electrochemistry, in particular, acid-base reactions are crucial because proton transfer is one of the most common processes in electrocatalysis, which often involves electron-proton coupled transfer reactions. These reactions determine the state and adsorption of reactive molecules, as well as the effects of pH on electrochemical reactions such as water electrolysis, CO2 reduction, and biomass valorization. Consequently, the acid dissociation constant (pKa) of molecules at electrified metal / water interfaces is a key parameter for understanding and optimizing electrocatalytic performance.Macroscopic concepts differ considerably at the electrified electrode / solution interfaces where the key steps of electrocatalysis take place. Indeed, the presence of a high electric field at the interface drastically alters the physicochemical environment, which can modulate reactivity and selectivity in complex reactions. There is currently a need for new molecules with diverse properties and applications in various environments, whose synthesis processes do not use catalysts based on critical and / or expensive materials, and which are less energy-intensive than conventional processes. Furthermore, it is now essential to meet increasingly stringent standards in terms of ease of implementation and operator safety, both with regard to the toxicity of the compounds being handled and the reaction conditions.

[0008] The inventors have developed synthetic processes for alkyl (C1-C5) imidazole derivatives, 2,2,6,6-tetramethylpiperidine-l-oxyl, which meet these conditions and allow for the production of a wide variety of compounds with diverse applications, such as those mentioned above, due to the variety of functional groups they can contain. Furthermore, these compounds allow for the control of the acid-base conditions of the reactions, contributing to their versatility in use and application.

[0009] The synthesized molecules are electroactive and constitute in particular new electroactive ionic liquids, and more particularly new electroactive protic ionic liquids, electroactive bicationic and new electroactive zwitterionic compounds, with various applications in the fields of energy storage, electrocatalysis, biocatalysis, electro-biocatalysis, electroactive (pH) buffers, thermo-electrochemical cells and imaging (optical contrast).

[0010] BRIEF SUMMARY OF THE INVENTION

[0011] Thus, a first object of the invention relates to a compound of general formula (I)

[0012] [Cheml] in which, with respect to the cation, l ≤ n ≤ 5 and R is selected from the following groups: a hydrogen atom, a C1-C5 alkyl, a C1-C5 alkyl sulfonate, a C1-C6 alkyl carboxylate, a C1-C5 hydroxyalkyl, a C1-C5 alkyl amine, a C1-C5 alkyl trimethylammonium, an alpha C3-C5 olefin or [Chem2] and in which A- is at least one anion derived from an acid.

[0013] The electroactive compounds of this family which include an imidazolium group combined with the TEMPO radical, due to the presence of functional groups have applications in very diverse physicochemical conditions.

[0014] In particular, the invention relates to a multifunctional electroactive compound having acid-base properties capable of receiving / donating a proton and / or zwitterion and / or bicationic and / or magnetic, of general formula (I):

[0015] [Cheml] in which, concerning the cation, l≤n≤5 and R is selected from the following groups: a hydrogen atom, a C1-C5 alkyl sulfonate, a C1-C6 alkyl carboxylate, a C1-C5 hydroxyalkyl, a C1-C5 alkyl amine, a C1-C5 alkyl trimethylammonium or [Chem2] and wherein A- is at least one anion derived from an acid. The present invention relates to multifunctional electroactive molecules possessing at least one of the following characteristics: acid-base, zwitterionic, bicationic, and magnetic properties. Multifunctional means that the present electroactive compound can be used in various applications: electrocatalysis, biocatalysis, bioelectrocatalysis, electrobiocatalysis, electroactive buffers (pH), thermoelectrochemical cells, imaging (optical contrast), or energy storage.

[0016] In the present invention, the R group exhibits Brønsted acid-base properties, meaning it allows proton transfer. Indeed, the Brønsted acid-base properties of the electroactive compound are provided by the R group, which comprises a substituent chemical group of the imidazolium nucleus, such as -OH, NH₂, COO-, or SO₃-, and the imidazole lone pair. Thus, the proton transfer capacity is so enhanced that it is no longer necessary to add an acid-base buffer during electrocatalytic reactions, for example. These R groups, and more generally these electroactive compounds, contribute significantly, by virtue of their structure, to stabilizing pH and transferring hydrogen. + allowing biocatalytic, bio-electrocatalytic, electro-biocatalytic reactions to proceed smoothly and chemically efficiently.

[0017] The proposed R groups also allow for the creation of electroactive bicationic and zwitterionic compounds. The functionalities provided by these specific R groups contribute, in particular, to regulating the interfacial properties of electrodes or improving ionic conductivity by promoting ion dissociation, in the context of energy storage applications.

[0018] The present invention relates to electroactive compounds with novel functionalities due to specific substituents in the imidazolium ring. These compounds represent opportunities in numerous application areas, such as: electrochemical energy storage with supercapacitors, organic batteries, and redox flow batteries in aqueous media; an opportunity for an all-organic catalyst; electrocatalysis for biomass valorization; and electrochemical information storage.

[0019] According to other optional features of the compounds and / or multifunctional electroactive compounds according to the invention, the latter may comprise one or more of the following features, alone or in combination: at least one anion derived from a protic acid is selected from chloride, bromide, iodide, bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate ions or mixtures thereof; these anions are of particular interest for electrochemical applications, and in particular for ionic liquids.

[0020] R is selected from the following groups: a C1-C5 alkyl, a C1-C5 hydroxyalkyl, a C1-C5 alkylamine, a C1-C5 alkyl trimethylammonium, a C3-C5 alpha olefin and A- is selected from chloride, bromide or iodide ions or mixtures thereof; These groups can have a varied impact on intermolecular interactions, thus diversifying their applications, and may be of particular, but not exclusive, interest in catalytic and biocatalytic applications (e.g., modulation of low-energy interactions with reactants in the medium).In particular, R is selected from the following groups: a C1-C5 hydroxyalkyl, a C1-C5 alkyl amine, a C1-C5 alkyl trimethylammonium, and A- is selected from chloride, bromide, or iodide ions or mixtures thereof; These groups can have a varied impact on intermolecular interactions, thus diversifying their applications, and may be of particular, but not exclusive, interest in catalytic and biocatalytic applications (e.g., modulation of low-energy interactions with reactants in the medium).

[0021] R = H and A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate or mixtures thereof; these compounds constitute electroactive protic ionic liquids of particular, but not exclusively, interest for reactions involving electron and proton transfers.

[0022] R is selected from a C1-C5 alkyl sulfonate, a C1-C6 alkyl carboxylate, or

[0023] [Chem2] and A- is selected from the ions: chloride, bromide, and TFSI or mixtures thereof; these compounds constitute zwitterionic compounds which can have applications under very diverse pH conditions, and whose solubility can be controlled by these conditions. The cation is selected from the following compounds:

[0024] [Table]

[0025]

[0026] The electrochemical properties of compounds containing these cations are specifically illustrated in the experimental section. In particular, the cation is selected from the following compounds:

[0027] [Table 2]

[0028]

[0029] The electrochemical properties of compounds including these imidazo ium cationic groups are specifically illustrated in the experimental part.

[0030] A second object of the invention relates to an electrochemical system comprising at least one compound as described above.

[0031] A third object of the invention relates to energy storage devices such as supercapacitors, batteries, symmetrical batteries, supercapacitor batteries, organic batteries, and redox flow batteries comprising such an electrochemical system. The compounds according to the invention have very diverse transfer rate properties (which allow for very diverse power outputs) and can be used in both capacitors and batteries.

[0032] A fourth object of the invention relates to an electroactive protic ionic liquid comprising as a cation a compound of formula (I):

[0033] [Cheml] in which l ≤ l ≤ 5 and R = H and A- is selected from the following anions: bistriflix oxide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, chloride, bromide, iodide, or mixtures thereof. Ionic liquids are of particular need in industry due to their diverse applications, such as organic synthesis, catalysis, chromatography, electrochemistry, extractions, nanoparticle preparation, polymer additives, etc.

[0034] In particular, the invention relates to an electroactive ionic liquid comprising as a cation a compound of formula (I):

[0035] [Cheml] in which concerning the cation, l≤n≤5 and R is selected from the following groups: a hydrogen atom, a C1-C5 alkyl sulfonate, a C1-C6 alkyl carboxylate, a C1-C5 hydroxyalkyl, a C1-C5 alkyl amine, a C1-C5 alkyl trimethylammonium or [Chem2] and in which A- is at least one anion derived from an acid.

[0036] According to other optional characteristics of the ionic liquids according to the invention, the latter may include the following characteristic: l≤n≤5 and R = H, and A- is selected from the following anions: bistrifli imidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, chloride, bromide, iodide or mixtures thereof;

[0037] A fifth object of the invention relates to the use of protic ionic liquids according to the invention as an organic electrocatalyst.

[0038] A sixth object of the invention relates to the use of the compounds according to the invention as an electrocatalyst in an electrochemical oxidation reaction.

[0039] In particular, the invention relates to the use of the multifunctional electroactive compounds according to the invention as an electrocatalyst in an electrochemical oxidation reaction.

[0040] Depending on optional characteristics of this use as an electrocatalyst in an electrochemical oxidation reaction, this may be: an oxidation of a compound comprising at least one alcohol function, in particular an indirect oxidation of 5-(hydroxy-methyl)furfural, or involved in the production of 2,5-furandicarboxylic acid.

[0041] According to optional characteristics of this use as an electrocatalyst in an electrochemical oxidation reaction, the electrocatalyst can be entirely made of organic compounds, preferably the electrocatalyst does not contain any metallic atoms.

[0042] A seventh object of the invention relates to an electro-active ionic liquid polymer comprising repeating motifs of formula (II):

[0043] [Chem3] in which, the <m<5 - l≤n≤5

[0044] A- is chosen from chloride, iodide or bromide ions, or mixtures thereof

[0045] X is chosen from Cl, Br, I.

[0046] Indeed, some of the compounds of the invention, by virtue of their vinylic function, are particularly suited to the formation of polymers, in particular brush polymers, on all types of supports; these polymers are of particular interest, for example, on the surface of electrodes in electrochemical systems.

[0047] Thus, an eighth object of the invention relates to a substrate modified on its surface by such an electro-active polymer ionic liquid of formula (II). According to an optional feature, the substrate is a current collector of an electrode.

[0048] A ninth object of the invention relates to the use of the compound of formula (III):

[0049] [Chem4] with l≤n≤5, as an intermediate product in a synthesis process of the compound of formula I according to the first object of the invention;

[0050] Indeed, this compound makes it possible to obtain, via an easy and safe synthesis process, the compounds of the invention.

[0051] In particular, the invention relates to a use of the aforementioned multifunctional electroactive compound for the electrochemical storage of energy, carried out for example in a supercapacitor, a battery, a symmetric battery, a supercapacitor battery, an organic battery, a redox flow battery comprising the electrochemical system.

[0052] Brief descriptions of the drawings

[0053] [Fig 1]: Voltammogram characteristic of an electroactive protic ionic liquid according to the invention (example of 3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium hydrogen sulfate).

[0054] [Fig 2]: Characterization by cyclic voltammetry of compounds of the invention, at the top the compound: 1-methyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium iodide; at the bottom the preferred compound: 1-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide.

[0055] [Fig 3]: Characterization by cyclic voltammetry of compounds of the invention, at the top the compound: 1- allyl -3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide; at the bottom the preferred compound: l-(2-aminoethyl) -3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide.

[0056] [Fig 4]: Characterization by cyclic voltammetry of a compound of the invention, l-(3- (trimethylammoniotrimethylammonio) propyl)-3-(2-oxo-2-(2,2,6,6-tetramethyltetramethyl-l-oxyl-4-piperidoxylpiperidoxyl)ethylethyl)imidazolium dibromide.

[0057] [Fig 5]: Characterization by cyclic voltammetry of electroactive zwitterionic compounds of the invention.

[0058] [Fig 6]: Schematic of the electrochemical oxidation of 5-(hydroxymethyl)furfural (HMF) mediated by the compounds of the invention, illustrated by l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium. HMF: 5-(hydroxymethyl)furfural, DFF: 2,5-diformylfuran; FFCA: 5-formylfuranoic acid, FDCA: 2,5-furandicarboxylic acid.

[0059] [Fig. 7]: Electrochemical oxidation of 5-(hydroxymethyl)furfural (HMF) by the compound of the invention, l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide: Cyclic voltammogram of the glassy carbon electrode for different electrolyte mixtures. The concentrations of compound 6 of the invention and HMF are each 1.0 mM in a borate buffer electrolyte (pH 9.2). Top: Cyclic voltammograms obtained at 100 mV·s 1, bottom: Cyclic voltammograms obtained at 5 mV.s 1 . HMF: 5-(hydroxymethyl)furfural.

[0060] Detailed description of the invention

[0061] Definitions The terms "(C1-C5) alkyl" or "C1-C5 alkyl" used in the present invention refer to a saturated, linear or branched hydrocarbon chain comprising from 1 to 5 carbon atoms, including, but not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, a branched pentyl, and n-pentyl. Preferably, the terms "(C1-C5) alkyl" or "C1-C5 alkyl" used in the present invention refer to a linear (i.e., unbranched) saturated hydrocarbon chain.

[0062] Bistriflimidide (or TFSI), or, in English, "bistriflimid", refers to the anion 1,1,1-trifluoro-N-(trifluoromethylsulfonyl)-methanesulfonimidate (IUPAC name) with the formula:

[0063] [Chem5]

[0064] "TEMPO" or "TEMPO radical" or "TEMPO group" refers to the (2,2,6,6-tetramethylpiperidin-l-yl)oxy or l-Xl-oxidanyl-2,2,6,6-tetramethylpiperidin (IUPAC name) group with the formula: [Chem6]

[0065] For the purposes of the invention, an imidazolium derivative or an "imidazole-based" compound refers to a compound comprising at least one such positively charged group.

[0066] Unless otherwise stated, the intervals mentioned include the bounds. Thus, unless otherwise specified, a value that is said to be between the values ​​x and y can be equal to x or y, and of course to any intermediate value.

[0067] The inventors developed and synthesized multifunctional organic molecules and materials from an imidazole-based synthon linked to a TEMPO group (l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole). From this same synthon, the inventors were able to obtain not only electroactive protic ionic liquids but also various families of organic molecules and materials. These molecules also possess acid-base properties due to the electron pair on the nitrogen of their imidazolium ring.This imidazolium nucleus can be functionalized via various groups, leading to a wide variety of compounds such as novel electroactive ionic liquids, protic electroactive ionic liquids, and electroactive zwitterions. These allow for the development of new organic materials for applications such as electrochromic devices, energy storage (including supercapacitors, organic batteries, redox flow batteries, and supercapacitor batteries), catalysis, electrocatalysis, biocatalysis, electrobiocatalysis, organocatalysis, thermoelectrochemical cells, and imaging (optical contrast). The diversity of these compounds allows for variability in the physicochemical conditions of use, such as pH and solvents.

[0068] The syntheses of these compounds do not use catalysts based on critical materials or expensive compounds. The synthesis conditions are not energy-intensive and pose a limited risk to the operator in terms of reagent toxicity or reaction conditions, which is a particular advantage.

[0069] Protic ionic liquids

[0070] Thus, a particular object of the invention relates to protic ionic liquids of the following formula:

[0071] [Chem7] where l≤n≤5 and A- is an anion known to form ionic liquids.

[0072] In a particular embodiment, these anions, in these protic ionic liquids are of the type tetrafluoroborate, hexafluorophosphate, halide, mesylate, tosylate, or triflate or mixtures thereof. In a preferred embodiment, A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, chloride, bromide, iodide or mixtures thereof.

[0073] In a particularly preferred embodiment, A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate or mixtures thereof.

[0074] In another particular embodiment, n=1, 2, 3, 4, or 5.

[0075] In another particular embodiment, n=l.

[0076] In another particular embodiment, n=l and A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, chloride, bromide, iodide or mixtures thereof.

[0077] In another particular embodiment, n=2 and A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, or mixtures thereof.

[0078] In another particular embodiment, n=3 and A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate or mixtures thereof.

[0079] In another particular embodiment, n=4 and A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate or mixtures thereof.

[0080] In another particular embodiment, n=5 and A- is selected from the following anions: bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate or mixtures thereof.

[0081] The protic ionic liquids of the invention have very diverse electrochemical properties, as illustrated by their electrochemical characterization and the wide range of current amplitudes they allow, as reported in the experimental section. This contributes to the wide variety of applications for which they can be used.

[0082] Compounds functionalized by an alkyl chain

[0083] Another particular object of the invention relates to derivatives of l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole comprising a functionalized alkyl group of the following formula: [Cheml] Or

[0084] - l ≤ n ≤ 5,

[0085] R is chosen from a C1-C5 alkyl, a C1-C5 hydroxyalkyl, a C1-C5 alkylamine, a C1-C5 alkyl trimethylammonium, a C3-C5 alpha olefin, and preferably chosen from a C1-C5 hydroxyalkyl, a C1-C5 alkylamine, a C1-C5 alkyl trimethylammonium, and

[0086] A- is selected from chloride, bromide or iodide ions or mixtures thereof.

[0087] In a particular embodiment, n=1, 2, 3, 4, or 5.

[0088] In a particular embodiment R is chosen from among the branched methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, or n-pentyl groups.

[0089] In a preferred embodiment, R is a C1-C5 hydroxyalkyl, chosen from hydroxymethyl,

[0090] 2-Hydroxyethyl, 1-Hydroxyethyl, 3-Hydroxypropyl, 2-Hydroxypropyl, 1-Hydroxypropyl, 4-Hydroxybutyl, 3-Hydroxybutyl, 2-Hydroxypropyl, 1-Hydroxypropyl, 5-Hydroxypentyl, 4-Hydroxypentyl, 3-Hydroxypentyl, 2-Hydroxypentyl, 1-Hydroxypentyl. Preferably, the hydroxyl group is in the terminal position of the alkyl chain at C1-C5, with R being selected from hydroxymethyl, 2-Hydroxyethyl, 3-Hydroxypropyl, 4-Hydroxybutyl, and 5-Hydroxypentyl.

[0091] In a preferred embodiment, R is a C1-C5 alkyl amine selected from the following groups: methylamine, 1-aminoethyl, 2-aminoethyl, 3-aminopropyl, 2-aminopropyl, 1-aminopropyl, 4-aminobutyl, 3-aminobutyl, 2-aminopropyl, 1-aminopropyl, 5-aminopentyl, 4-aminopentyl, 3-aminopentyl, 2-aminopentyl, and 1-aminopentyl. Preferably, the amine group is in the terminal position of the C1-C5 alkyl chain, with R then being selected from methylamine, 2-aminoethyl,

[0092] 3-aminopropyl, 4-aminobutyl, and 5-aminopentyl.

[0093] In a preferred embodiment R is a C1-C5 alkyl trimethylammonium group, selected from the following trimethylammonium methyl, 1-trimethylammonium ethyl, 2-trimethylammonium ethyl, 3-trimethylammonium propyl, 2-trimethylammonium propyl, 1-trimethylammonium propyl, 4-trimethylammonium butyl, 3-trimethylammonium butyl, 2-trimethylammonium butyl, 1-trimethylammonium butyl, 5-trimethylammonium pentyl, 4-trimethylammonium pentyl, 3-trimethylammonium pentyl, 2-trimethylammonium pentyl, 1-trimethylammonium pentyl groups. Preferably, the trimethylammonium group is in the terminal position of the alkyl chain at C1-C5, R then being selected from trimethylammonium methyl, 2-trimethylammonium ethyl, 3-trimethylammonium propyl, 4-trimethylammonium butyl, and 5-trimethylammonium pentyl.

[0094] In one particular embodiment, R is an alpha olefin selected from the allyl, 3-butenyl, and 5-pentenyl groups. These compounds are of particular interest because their alpha vinyl function can be used for polymerization purposes, and to modify, for example, functionalized surfaces such as electrode surfaces.

[0095] Another particular object of the invention relates to zwitterionic compounds derived from l-(2-oxo- 2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole of the following formula:

[0096] [Cheml]

[0097] - l ≤ n ≤ 5

[0098] R is chosen from R is selected from a C1-C5 alkyl sulfonate, an alkyl carboxylate

[0099] A- is selected from the ions: chloride, bromide and bistriflimidide (TFSI) or their mixtures.

[0100] In a particular embodiment, n=1, 2, 3, 4, or 5. In a particular embodiment, R is a C1-C5 alkyl sulfonate selected from sulfonatomethyl, 2-sulfonatoethyl, 1-sulfonatoethyl, 3-sulfonatopropyl, 2-sulfonatopropyl, 1-sulfonatopropyl, 4-sulfonatobutyl, 3-sulfonatobutyl, 2-sulfonatobutyl, 1-sulfonatobutyl, 5-sulfonatopentyl, 4-sulfonatopentyl, 3-sulfonatopentyl, 2-sulfonatopentyl, and 1-sulfonatopentyl. Preferably, the sulfonate group is in the terminal position of the alkyl chain at C1-C5, R then being selected from sulfonatomethyl, 2-sulfonatoethyl, 3-sulfonatopropyl, 4-sulfonatobutyl, and 5-sulfonatopentyl.

[0101] In a particular embodiment, R is a C1-C6 alkyl carboxylate selected from carboxymethyl, 2-carboxyethyl, 1-carboxyethyl, 3-carboxypropyl, 2-carboxypropyl, 1-carboxypropyl, 4-carboxybutyl, 3-carboxybutyl, 2-carboxybutyl, 1-carboxybutyl, 5-carboxypentyl, 4-carboxypentyl, 3-carboxypentyl, 2-carboxypentyl, 1-carboxypentyl, 6-carboxyhexyl, 5-carboxyhexyl, 4-carboxyhexyl, 3-carboxyhexyl, 2-carboxyhexyl, 1-carboxyhexyl. Preferably, the carboxyl group is in the terminal position of the alkyl chain in C1-C6, R then being selected from carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl, 5-carboxypentyl, 6-carboxyhexyl.

[0102] In a particular embodiment, R is [Chem2]

[0103] These compounds are therefore zwitterions whose solubility can be modulated according to the ionic strength of the solvent in which they are contained. This is advantageous for the recycling and / or reuse of these compounds, and diversifies the possibilities for interaction with other components (and therefore the choice of these compounds), for example, polar solvents or electrodes. In electrochemical applications, for example, these compounds have the advantage of being usable as both cathodic and anodic materials, which is particularly beneficial in terms of resource conservation and ease of recycling.

[0104] Electro-active ionic liquid polymers

[0105] Another particular object of the invention relates to an electro-active ionic liquid polymer comprising repeating motifs of formula (II): [Chem3] in which, l ≤ m ≤ 5

[0106] - l ≤ n ≤ 5

[0107] A- is chosen from chloride, iodide or bromide ions, or mixtures thereof

[0108] X is chosen from Cl, Br, I.

[0109] In a particular embodiment of the ionic liquid polymer according to the invention, n=1, n=2, n=3, n=4, or n=5. Preferably, n=1, which contributes to giving the polymer an ordered, brush-like structure, advantageous for heterogeneous electron transfer, that is, electron transfer between species in different phases. The imidazole group advantageously contributes to this structure.

[0110] In a particular embodiment of the ionic liquid polymer according to the invention, m=1, m=2, m=3, m=4 or m=5.

[0111] This ionic liquid polymer of the invention can be grafted onto a surface such as a glass surface, or a current collector, such as the current collector of an electrode.

[0112] When the surface is an electrode, it is preferably a carbon electrode, more preferably a flexible carbon electrode, advantageously transparent, preferably to sunlight, such as a graphene electrode.

[0113] The surface can be flat or have a 3D structure such as nickel foam, graphene foam, or carbon nanotube and graphene composites.

[0114] When grafted onto the surface of a substrate, the polymeric ionic liquids of the invention exhibit a controlled, so-called "brush" architecture in which they are arranged in a controlled and ordered manner. This structure is particularly advantageous because it is highly ordered and facilitates electron exchange and potentially increases catalytic activity.

[0115] These brush polymers are of particular application in electrochemical devices, sensors, especially microfluidic devices.

[0116] Use of the compounds of the invention as organic catalysts.

[0117] The compounds of the invention, due to the presence of the tempo radical, are of particular interest in electrocatalytic applications, for example as enzymatic cofactors, or in electrochemical oxidation reactions.

[0118] Such electrochemical oxidation reactions, such as the electrochemical oxidation of alcohol derivatives, are of particular interest in the context of biomass valorization (and the valorization of compounds such as cellulose or other saccharide derivatives, for example). For instance, the compounds according to the invention can catalyze the oxidation of glycerol, which is known to be a co-product of biodiesel production, or the oxidation of 5-(hydroxymethyl)furfural, which is a cellulose degradation product. Examples of the efficiency of the electrocatalytic oxidation process of 5-(hydroxymethyl)furfural with the compounds of the invention are presented in the experimental section and illustrated in Figures 6 and 7 for the compounds.

[0119] Thus, a particular object of the invention relates to the use of the compounds according to the invention as organic electrocatalysts. A particular embodiment is such use in an electrochemical oxidation reaction of a compound comprising at least one alcohol functional group.

[0120] In a preferred embodiment, at least one compound comprising at least one alcohol function is glycerol or 5-(hydroxymethyl)furfural.

[0121] The oxidation of 5-(hydroxymethyl furfural) by the compounds of the invention leads to the production of 2,5-furandicarboxylic acid.

[0122] Also, electroactive protic ionic liquids are of particular interest for catalyzing reactions associating electron and proton transfers such as the regeneration of enzymatic cofactors or their use as artificial enzymatic cofactors.

[0123] One embodiment consists of using a protic ionic liquid according to the invention as an organic electrocatalyst.

[0124] Another particular embodiment of the invention relates to the use of a protic ionic liquid according to the invention in enzymatic biocatalysis processes, to regenerate enzymatic cofactors or as an enzymatic cofactor.

[0125] The electrochemical characterization data for the compounds of the invention, as illustrated in the experimental section, highlight the potential of these compounds in the field of electrochemical systems, and more specifically in electrochemical energy storage. This obviously applies to the protic ionic liquids according to the invention, but also to other compounds, as demonstrated by the experimental data.

[0126] An object of the invention is therefore an electrochemical system comprising at least one compound according to the invention. In a particular embodiment, such a system is selected from:

[0127] Electrochemical energy storage systems,

[0128] Supercapacitors,

[0129] Supercapacitor batteries

[0130] Organic batteries,

[0131] Redox flow batteries, and

[0132] Symmetrical batteries.

[0133] Supercapacitors result from the marriage between supercapacitors and batteries; they combine high energy density and high power.

[0134] The bipolar bi-redox molecules of the invention also allow the development of all-solid or quasi-solid electrochemical energy storage systems. Thanks to their configuration, redox flow batteries decouple the energy density, which is determined by the reservoir volume and the concentration of electroactive species, from the power density, which is controlled by the electrode surface area and the electron transfer rate. (based on imidazole linked to a...) TEMPO

[0135] Another object of the invention is the imidazole-based synthon linked to a TEMPO group (which serves as an intermediate product for the synthesis of all the compounds of the invention.

[0136] In a particular embodiment, said synthon has formula (III):

[0137] [Chem4]

[0138] with l ≤ n ≤ 5, preferably 2 <n<5. Dans un mode de réalisation n =2.

[0139] In an embodiment n=3.

[0140] In another embodiment n=4.

[0141] A particular object of the invention relates to the use of this synthon (alkyl (C1-C5) imidazole 2,2,6,6-tetramethylpiperidine-l-oxyl) of formula (III):

[0142] [Chem4] with l≤n≤5, in a process for synthesizing a compound of the invention as previously described.

[0143] In an embodiment n = 2.

[0144] In an embodiment n=3.

[0145] In another embodiment n=4 Synthesis processes for the compounds of the invention

[0146] Process for the synthesis of electroactive protic ionic liquids:

[0147] [Chem8]

[0148] 5

[0149] One object of the invention is a process for synthesizing the protic ionic liquids of the invention which comprises the following steps: i) Mixing and dissolving 1 equivalent of the imidazole-based synthon linked to a group

[0150] TEMPO (1 equiv.) and 1 equivalent of practical dissolved acid of distilled acetonitrile,

[0151] 10 ii Agitation for at least 6 hours, preferably at least 8 hours, preferably at least 12 hours, at room temperature, iii Removal of solvent by evaporation.

[0152] In one particular embodiment, at step i), the reaction volume is between 5 mL and

[0153] 15 50 mL, preferably between 10 mL and 40 mL, preferably between 20 mL and 30 mL.

[0154] In a preferred embodiment, the practical acid is selected from: sulfuric acid, phosphoric acid, bistriflimidic acid, triflic acid, citric acid, acetic acid, or mixtures thereof.

[0155] In one particular embodiment in step iii) the solvent is removed using an evaporator

[0156] 20 rotary and traces of water are removed by vacuum pump for at least 3 hours, at least 6 hours, preferably at least 8 hours, preferably at least 12 hours.

[0157] Synthesis process for imidazole-based synthon derivatives linked to a TEMPO group

[0158] 25 comprising a functionalized alkyl:

[0159] [Chem9]

[0160] With m = 1 to 5 and n = 1 to 5, m and n being independent, X selected from Cl, Br, I and Z selected from OH, NH2, [-N(CH3) 3+ ], an ethenyl group, H, and preferably Z selected from H, OH, NH2 and [-N(CH3) 3+ and even more preferably Z selected from among OH, NH2 and [-N(CH3) 3+ ].

[0161] One object of the invention is a process for synthesizing imidazole-based synthon derivatives linked to a TEMPO group comprising a functionalized alkyl group, said process comprising the following steps: i) Mixing and dissolving 1 equivalent of imidazole-based synthon linked to a TEMPO group (1 equiv.) and 1 to 5 equivalents of halide reagent in distilled acetonitrile, ii) Stirring for at least 12 hours, preferably at least 18 hours, preferably at least 20 hours, or even 24 hours at a temperature between 30°C and 50°C, preferably 40°C, iii) Removal of the solvent by evaporation at room temperature, iv) Washing and drying

[0162] In a particular embodiment, at step i), the reaction volume is between 5 mL and 50 mL, preferably between 10 mL and 40 mL, preferably between 20 mL and 30 mL.

[0163] In one particular embodiment in step iii) the solvent is removed using a rotary evaporator.

[0164] In one particular embodiment in step iv) the product is washed with ethyl acetate and dried by vacuum pump for at least 12 h, preferably at least 18 h, preferably at least 24 h, to remove any residual solvent and reagent.

[0165] Synthesis process for zwitterionic derivatives of synthon based on imidazole linked to a group

[0166] TEMPO:

[0167] [ChemlO]

[0168] With the <m<5, l≤n≤5, Y choisi parmi [Chem2] 0 , S03 _ , and COO , and X chosen from the following anions: chloride, bromide, bistriflimidide.

[0169] Another object of the invention is a process for synthesizing zwitterionic derivatives of imidazole-based synthon linked to a TEMPO group, said process comprising the following steps: i) Dissolving 1 equivalent of imidazole-based synthon in acetonitrile; ii) Adding the second reagent (1 equivalent) to the reaction mixture and then heating for at least

[0170] 12h, preferably at least 18h, preferably at least 24h, between 40°C and 70°C, iii) Removal of solvent by evaporation at room temperature, iv) Washing and drying.

[0171] In a particular embodiment, at step i), the reaction volume is between 5 mL and 50 mL, preferably between 10 mL and 40 mL, preferably between 20 mL and 30 mL.

[0172] In one particular embodiment in step iii) the solvent is removed using a rotary evaporator.

[0173] In one particular embodiment in step iv) the product is washed with dichloromethane and ethyl acetate and dried by vacuum pump for at least 12 h, preferably at least 18 h, preferably at least 24 h.

[0174] Methods for obtaining polymers from the compounds of the invention comprising an α-olefin function.

[0175] Surface-initiated atom transfer-controlled radical polymerization (SI-ATRP) is particularly suited to the compounds of the invention; it is illustrated in the experimental part.

[0176] Another object of the invention is therefore a process for obtaining polymers from the compounds of the invention comprising an α-olefin function, said process taking place in two steps: i) Preparation of the initiator layer

[0177] This involves grafting, by electrochemical oxidative grafting, an organic radical precursor (terminated by a halogen) onto a surface (for example, an electrode), such as a primary alkyl bromide. Halogen-terminated substrates are thus obtained. ii) Functionalization of the organic radical precursor by a radical reaction to covalently link the compounds of the invention comprising a vinyl functional group.

[0178] In one particular embodiment, at step i), the primary alkyl bromide is 2-bromoethylamine.

[0179] In one embodiment, at step i), grafting is carried out by cyclic voltammograms, in aqueous solution containing between 10" 3 M and 10 -2 M of 2-bromoethylamine and between 10 -2 M and 1 M of LiCIO4, from 0.5 to 1.6 V vs SCE for 20 cycles.

[0180] In another embodiment, at step i), after the electrochemical modification, the substrates are rinsed with water and then subjected to sonication.

[0181] In one embodiment, in step ii) the compound of the invention to be grafted is dissolved in acetone with the pentamethyldiethylenetriamine (PMDETA) ligand. The catalyst, CuCl, and the deactivator, CuCl, are then introduced, followed by two additional freeze-pump-out cycles. The surface modified by the initiator is immersed in the reaction mixture under argon flow. The SI-ATRP is carried out at 50 °C for 30 minutes. Afterward, the electrode is rinsed with acetone and sonicated in acetone for 2 minutes.

[0182] Synthesis process of synthon (alkyl (C1-C5) imidazole 2,2,6,6-tetramethylpiperidine-l-oxyl) according to the invention:

[0183] Step 1: Synthesis of 2,2,6,6-tetramethyl-l-oxyl-4-piperidinyl 2-chloro C1-C5 carboxylate i) Dissolve 1 equivalent of 4-OH TEMPO (Sigma-Aldrich) and 1 equivalent of C1-C5 carboxylate chloride (Sigma-Aldrich) from distilled dichloromethane (40 mL) with rapid stirring, ii) Add 1 equivalent of pyridine (Sigma-Aldrich) dropwise while cooling to a temperature between 0-5°C, iii) Maintain the reaction with stirring at a temperature between 0-5°C for at least 1 hour, preferably at least 2 hours, preferably at least 3 hours, and even more preferably at least 4 hours, iv) Maintain with stirring at room temperature for at least 12 hours, preferably at least 14 hours, preferably at least 16 hours, and even more preferably at least 18 hours, v) The precipitate is collected, then washed with a 3M aqueous HCl solution and a saturated aqueous NaCl solution,vi) Recovery of the organic phase, which is dried over anhydrous MgSO4, vii) Evaporation of the solvents, preferably under vacuum, viii) Precipitation of the solvent by evaporation at room temperature.

[0184] A solid orange is obtained with a yield of 90%.

[0185] Step 2: Preparation of l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)alkyl(C1-C5))imidazole i) Dissolve 1 equivalent of imidazole (Sigma-Aldrich) from distilled THF with stirring, ii) Dissolve 1 NaH in distilled THF with stirring, iii) Add dropwise the NaH solution to the imidazole solution, iv) Keep under stirring for at least one hour at room temperature, v) Add 1 equivalent of the product obtained in step 1, vi) Heat between 45°C and 55°C for at least 8 hours, preferably at least 10 hours, preferably at least 12 hours.vii) Maintaining the previous solution under stirring for at least one hour at room temperature with 4-OH TEMPO (Sigma-Aldrich) and 1 equivalent of C1-C5 carboxylate chloride (Sigma-Aldrich) of distilled dichloromethane (40 mL) under rapid stirring, viii) Hydrolysis of the reaction solution by adding distilled water, ix) Evaporation of the THF, x) Dissolution of the precipitate in dichloromethane, washing with water, xi) Separation of the organic phase, drying over anhydrous MgSO4 and evaporation preferably under vacuum, the viscous solid obtained being l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)alkyl(C1-C5))imidazole, synthon according to the invention. EXAMPLES.

[0186] Abbreviations used:

[0187] DCM: dichloromethane

[0188] DMF: dimethylformamide

[0189] ACN: acetonitrile

[0190] 4-OH-Tempo: 4-hydroxy-2,2,6,6-tetramethyl-l-piperidin-l-yloxy, free radical

[0191] SCE: saturated calomel electrode

[0192] RT: ambient temperature

[0193] THF: tetrahydrofuran

[0194] HTFSI: bistriflimidic acid

[0195] HMF: 5-(hydroxymethyl)furfural

[0196] DFF: 2,5-diformylfuran

[0197] FFCA: 5-Formylfuranoic acid

[0198] FDCA: 2,5-furandicarboxylic acid

[0199] PMDETA: pentamethyldiethylenetriamine equiv.: equivalent 1. Synthesis of the imidazole-based synthon linked to a TEMPO group of formula III

[0200] The synthesis involves two steps, as specified below:

[0201] [Chemll]

[0202] They are detailed below for the synthesis of l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (n=l) and readily derivable for n=2, 3, 4, or 5. 1.1 Step 1: Preparation of the intermediate 2,2,6,6-tetramethyl-l-oxyl-4-piperidinyl 2-chloroacetate

[0203] 4.3 g (25 mmol) of 4-OH-TEMPO (Sigma-Aldrich) and 3.11 g (27.5 mmol) of chloroacetyl chloride (Sigma-Aldrich) are added to 40 mL of distilled dichloromethane with rapid stirring. Then, 2.18 g (27.5 mmol) of pyridine (Sigma-Aldrich) is slowly added dropwise to the previous solution while cooling to 0–5°C. The resulting mixture is stirred at 0–5°C for 4 hours and then at room temperature for 18 hours. After the reaction, the precipitate is collected and washed with 3 M aqueous HCl and saturated aqueous NaCl. The organic phase is separated, dried over anhydrous MgSO4, and evaporated using a rotary evaporator, yielding an orange solid. Yield: 90% 1.16 (12H, CH3), 2.07 (2H, CH2), 4.34 (4H, CH2), 5.15 (1H, CH).

[0204] 1.2 Step 2: Preparation of l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole

[0205] 0.81 g (12 mmol) of imidazole (Sigma-Aldrich) is added to 30 mL of distilled THF with stirring. Then, 0.36 g (15 mmol) of NaH in 10 mL of distilled THF is slowly added dropwise to the previous solution with stirring. The resulting mixture is stirred for 1 hour at room temperature. After 1 hour, 3 g (12 mmol) of the intermediate 2,2,6,6-Tetramethyl-1-oxyl-4-piperidinyl 2-chloroacetate is added to the reaction solution. The solution is heated to 50°C overnight. After the reaction, two phases (solid and liquid) are observed. The reaction solution is then hydrolyzed with 5 mL of distilled water. The THF is then evaporated. The precipitate is dissolved in 50 mL of dichloromethane, then washed with water (100 mL x 3 times). The organic phase is separated, dried over anhydrous MgSO4, and evaporated using a rotary evaporator, yielding a viscous orange compound.

[0206] Yield: 65%

[0207] TH NMR (400 MHz, DMSO-d6) 6 0.8-1.9 (12H, CH3), 2.16 (2H, CH2), 4.9 (4H, CH2), 5.35 (1H, CH), 6.9 (1H, CH), 7.16 (1H, CH), 7.69 (1H, CH)

[0208] 2. Electroactive protic ionic liquids

[0209] 2.1 General Protocol for the Synthesis of Protic Ionic Liquids Imidazole-based synthon linked to a TEMPO group (1 equiv.) and protic acids (1 equiv., selected from sulfuric acid, phosphoric acid, bistriflimidic acid, triflic acid, citric acid, and acetic acid) dissolved in 20 mL of distilled acetonitrile are mixed together in a round-bottom flask. The reaction is then stirred overnight at room temperature. The solvent is removed using a rotary evaporator, and traces of water are removed by vacuum pump overnight to obtain a reddish-brown liquid, which constitutes the protic ionic liquid.

[0210] [Cheml2]

[0211] 2.2 Electrochemical characterization of protic ionic liquids

[0212] For the electrochemical characterization of protic ionic liquids according to the invention, a conventional three-electrode cell is used. A platinum wire is used as an auxiliary electrode. An AgCl / Ag electrode is used as a reference electrode. A 3 mm diameter glassy carbon (GCE) electrode is used as the working electrode. Before use, the working electrodes are successively polished with silicon carbide (SiC) paper with a 5 µm grain size (Struers) and DP-Nap paper with a 1 µm grain size (Struers) containing a 0.3 µm Al₂O₅ suspension (Struers). After polishing, the electrode is thoroughly rinsed with ultrapure water (resistivity of 18.2 Ω·cm). The potentiostat used in this study is the CHI 660C (CH Instruments, manufactured in Texas, USA).

[0213] As an example, the voltammogram of the protic ionic liquid obtained with sulfuric acid is shown in Figure 1; similar voltammograms are observed for the other protic ionic liquids of the invention. Cyclic voltammograms (CVs) were obtained in an aqueous solution of protic ionic liquid at a concentration of 1 mM at a scan rate of 100 mV / s. The measured standard potentials (or half-wave potential, E1 / 2) are reported in Table 3 below. [Tables]

[0214] 3. Derivatives of l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole comprising a functionalized alkyl.

[0215] 3.1 General synthesis protocol

[0216] Synthesis process for derivatives of l-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole comprising a functionalized alkyl: [Chem13]

[0217] With n=l to 5, X selected from Cl, Br, I and Z selected from an alkyl group, OH, NH2, [-N(CH3) 3+ ], an ethenyl group, H, and preferably Z selected from H, OH, NH2 and [-N(CH3) 3+ ]and even more preferably Z selected from among OH, NH2 and [-N(CH3) 3+ 1-(2-oxo-2-(2,2,6,6-tetramethyl-1-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in ethyl acetate (20 mL), and then halide reagent (1-5 mmol, 1-5 equiv.) is added to the reaction mixture before heating for 18-24 hours at 40°C. After returning to room temperature, the solvent is evaporated using a rotary evaporator, yielding a viscous reddish-brown liquid. The product is then washed with ethyl acetate and vacuum-dried for 24 hours to remove any residual solvent and reagent.

[0218] 3.2 Example of Synthesis of l-Methyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium iodide (iodide of compound 5)

[0219] [Cheml4]

[0220] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then methyl iodide (Sigma-Aldrich, 5 mmol, 5 equiv.) is added dropwise to the reaction mixture before heating for 18 hours at 40°C. After returning to room temperature, the solvent and methyl iodide are removed using a rotary evaporator, yielding a viscous reddish-brown oil. The product is then washed with ethyl acetate and vacuum-dried for 24 hours to remove any residual solvent and methyl iodide. Yield: 99% -1.4 (12H, 4CH3), 1.9 (2H, CH2), 3.7 (3H, CH2), 4.2 (4H, CH2), 5.2 (1H,

[0221] CH), 7.75 (2H, 2CH), 9.12 (1H, CH).

[0222] 3.3 Example of the synthesis of 1-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-1-oxyl-4-piperidoxyl)ethyl)imidazolium bromide

[0223] [Cheml5]

[0224] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then 2-bromoethanol (Sigma-Aldrich, 3 mmol, 3 equiv.) is added to the reaction mixture before heating for 18 hours at 40°C. After returning to room temperature, the solvent and reagent are removed using a rotary evaporator, yielding a viscous reddish-brown oil. The product is then washed with ethyl acetate and vacuum-dried for 24 hours to remove any residual solvent and reagent.

[0225] Yield: 82% -1.4 (12H, 4CH2), 1.9 (2H, CH2), 3.6 (1H, OH ), 3.7 (6H, CH2), 5.3 (1H, CH), 7.4 (1H, 1CH), 7.8 (1H, 1CH), 8.4 (1H, CH)

[0226] 3.4 Example of synthesis of 1-allyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-1-oxyl-4-piperidoxyl)ethyl)imidazolium bromide

[0227] [Cheml6]

[0228] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then 2-bromoallyl (Sigma-Aldrich, 2 mmol, 2 equiv.) is added dropwise to the reaction mixture before heating for 18 hours at 40°C under argon. After cooling to room temperature, the solvent and reagent are removed using a rotary evaporator, yielding a viscous reddish-brown oil. The product is then washed with ethyl acetate and vacuum-dried for 24 hours to remove any residual solvent and reagent.

[0229] Yield: 65% -1.7 (12H, 4CH2), 2.2 (2H, CH2), 4.94 (2H, CH2), 5.26 (2H, CH2), 5.4 (4H, 2CH2), 5.76 (1H, CH), 6.07 (1H, CH), 7.78 (2H, 2CH), 9.20 (1H, CH)

[0230] 3.5 Example of the synthesis of l-(2-aminoethyl)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide

[0231] [Cheml7] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then 2-bromoethylamine (Sigma-Aldrich, 2 mmol, 2 equiv.) is added to the reaction mixture before heating for 18–24 hours at 40°C. After returning to room temperature, the solvent and reagent are removed using a rotary evaporator, yielding a viscous reddish-brown oil. The product is then washed with ethyl acetate and vacuum-dried for 24 hours to remove any residual solvent and reagent.

[0232] Yield: 83% -1.2 (12H, 4CH3), 2.42 (2H, CH2), 4.22 (2H, CH2), 4.40 (2H, CH2), 4.51 (4H, 2CH2), 5.17 (1H, 1CH), 5.36 (2H, NH2), 8.7 (1H, 1CH), 8.9 (1H, 1CH), 9.20 (1H, CH).

[0233] 3.6 Example of synthesis of l-(3-(trimethylammonio)propyl)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium dibromide

[0234] [Cheml8]

[0235] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then (3-bromopropyl)trimethylammonium bromide (Sigma-Aldrich, 2 mmol, 2 equiv.) is added to the reaction mixture before heating for 18–24 hours at 40°C. After returning to room temperature, the solvent and reagent are removed using a rotary evaporator, yielding a viscous reddish-brown oil. The product is then washed with ethyl acetate and vacuum-dried for 24 hours to remove any residual solvent and reagent. Yield: 91% 1.65 (12H, 4CH3), 1.90 (2H, CH2), 2.07 (3H, CH3), 2.22 (3H, CH3), 2.33 (3H, CH3), 3.43 (2H, CH2), 3.60 (2H, CH2), 3.73 (2H, CH2), 4.39 (2H, CH2), 5.01 (1H, 1CH), 5.53 (2H, CH2), 7.87 (1H, 1CH), 7.97 (1H, 1CH), 9.38 (1H, CH)

[0236] 3.7 Electrochemical Properties

[0237] Electrochemical characterization of protic ionic liquids

[0238] For the electrochemical experiments, a conventional three-electrode cell is used. A platinum wire is used as the auxiliary electrode. An AgCl / Ag electrode is used as the reference electrode. A 3 mm diameter glassy carbon (GCE) electrode is used as the working electrode. Before use, the working electrodes are polished successively with 5 µm SiC paper (Struers) and 1 µm DP-Nap paper (Struers) with a 0.3 µm Aloa suspension (Struers). After polishing, the electrode is thoroughly rinsed with ultrapure water (18.2 MO cm⁻¹). The potentiostat used in this study is the CHI 660C (CH Instruments, manufactured in Texas, USA).

[0239] The cyclic voltammograms (CVs) shown in Figures 2, 3, and 4 were obtained in a 0.1 M aqueous KCl solution of redox-active functional derivatives at a concentration of 1 mM and a scan rate of 100 mV / s. The measured standard potentials (or half-wave potential, EI / 2) are reported in Table 4 below.

[0240] [Table 4] 4. Electroactive zwitterionic compounds

[0241] 4.1 General synthesis protocol

[0242] [Cheml9] the following: chloride, bromide, bistriflimidide.

[0243] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and the second reagent (1 mmol, 1 equiv.) is added to the reaction mixture before heating for 24 hours at 40–70°C. After returning to room temperature, the solvent is evaporated using a rotary evaporator. The crude product is then washed with dichloromethane and ethyl acetate and vacuum-dried for 24 hours, yielding a viscous reddish-brown liquid.

[0244] 4.2 Synthesis of l-(3-sulfonatopropyl)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium chloride

[0245] [Chem20]

[0246] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then 1,3-propanesultone (Sigma-Aldrich, 1 mmol, 1 equiv.) is added to the reaction mixture before heating for 24 hours at 70°C. After returning to room temperature, the solvent is evaporated using a rotary evaporator. The crude product is then washed with dichloromethane and ethyl acetate and dried under vacuum for 24 hours, resulting in a viscous reddish-brown liquid. Yield: 87% 1.41 (12H, 4CH3), 2.40 (4H, 2CH2), 3.532 (2H, CH2), 3.40 (2H, CH2), 4.41 (2H, CH2), 4.47 (2H, CH2), 5.20 (1H, 1CH), 7.75 (H, CH), 7.84 (1H, CH), 9.19 (1H, CH)

[0247] 4.3 Synthesis of l-(pentanoate)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium

[0248] [Chem21]

[0249] L-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazole (1 mmol, 1 equiv.) is dissolved in acetonitrile (20 mL), and then 5-bromovaleric acid (Sigma-Aldrich, 1 mmol, 1 equiv.) is added to the reaction mixture before heating for 24 hours at 70°C. After returning to room temperature, the solvent is evaporated using a rotary evaporator. The crude product is then washed with dichloromethane and ethyl acetate and subsequently dried under vacuum for 24 hours, yielding a viscous reddish-brown liquid.

[0250] Yield: 70% 1.85 (12H, 4CH3), 2.25 (4H, 2CH2), 3.53 (2H, CH2), 3.60 (2H, CH2), 5.54 (1H, 1CH), 5.11 (2H, CH2), 5.53 (2H, CH2), 7.79 (2H, 2CH), 9.15 (1H, CH)

[0251] 4.4 Synthesis of 3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium l-chlorosulfonyl(trifluoromethylsulfonyl)imide

[0252] This synthesis involves two steps starting from l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide, as illustrated and detailed below:

[0253] Step 1: Synthesis of 1-chlorosulfate-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide [Chem22]

[0254] Starting from l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide, the first step is to synthesize the intermediate compound l-chlorosulfateethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide.

[0255] A suspension of l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium bromide (30 mmol, 1 equiv.) in anhydrous diethyl ether (50 mL) is cooled in an ice bath. Chlorosulfonic acid (30 mmol, 1 equiv., 2.0 mL) is then added dropwise over 2.5 hours. The mixture is then stirred for 40 hours at room temperature. The reaction mixture is cooled in an ice bath before the addition of phosphorus trichloride (5.4 mL, 60 mmol). After 2 hours of cold stirring, the reaction mixture is stirred continuously for 24 hours at room temperature. The solvent is then evaporated under reduced pressure, and the residual solid is washed with boiling petroleum ether (boiling point 45-60°C) (100 mL) to obtain reddish-brown crystals. The crude product was then recrystallized in boiling petroleum ether (100 mL twice). Reddish-orange crystals are obtained with a yield of 65%.

[0256] Step 2: Synthesis of 3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium 1-chlorosulfonyl(trifluoromethylsulfonyl)imide

[0257] [Chem23]

[0258] (i) Ethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-1-oxyl-4-piperidoxyl)ethyl)imidazolium bromide (leq.) from step 1 is placed in acetonitrile and trifluoromethanesulfonamide (leq.) to which sodium carbonate is added, and the mixture is then maintained at 70°C with stirring for at least 24 hours, (ii) the acetonitrile is evaporated, the crude product is dissolved in absolute ethanol, and the resulting mixture is filtered to remove the carbonate,

[0259] (iii) the liquid phase is evaporated under reduced pressure to give the electroactive magnetic product.

[0260] Yield: 65% -1.2 (12H, 4CH3), 2.42 (2H, CH2), 4.22 (2H, CH2), 4.40 (2H, CH2), 4.51 (4H, 2CH2), 57.4 (1H, 1CH), 7.8 (1H, 1CH), 8.4 (1H, CH) 19 F NMR (DMSO): 78.70 (s, 3F).

[0261] 4.5 Electrochemical Properties

[0262] Electrochemical characterization

[0263] For the electrochemical experiments, a conventional three-electrode cell is used. A platinum wire is used as the auxiliary electrode. An AgCl / Ag electrode is used as the reference electrode. A 3 mm diameter glassy carbon (GCE) electrode is used as the working electrode. Before use, the working electrodes are polished successively with 5 µm SiC paper (Struers) and 1 µm DP-Nap paper (Struers) with a 0.3 µm Aloa suspension (Struers). After polishing, the electrode is thoroughly rinsed with ultrapure water (18.2 MO cm⁻¹). The potentiostat used in this study is the CHI 660C (CH Instruments, manufactured in Texas, USA).

[0264] Cyclic voltammograms were performed in a 0.1 M aqueous KCl solution of redox-active functional derivatives at a concentration of 1 mM and a scan rate of 100 mV / s. They are shown in Figure 5 for the compounds tested. The measured standard potentials (or half-wave potential, EI / 2) are reported in Table 5 below.

[0265] [Table 5] 5. Obtaining polymers from compounds containing an α-olefin function

[0266] Surface-initiated atom transfer-controlled radical polymerization (SI-ATRP)

[0267] 5.1 General Protocol

[0268] One of the advantages of this technique is that very robust and stable polymer brushes are attached to the covalently bonded initiator films.

[0269] The immobilization of polymers based on the SI-ATRP process is divided into two steps. The first step is the preparation of the substrate modified by an initiator. Thus, halogen-terminated substrates can be obtained by the electrochemical oxidative grafting of amino derivatives onto a glassy carbon electrode. This immobilization creates an initiator for the ATRP process via the halogen group. This step is illustrated below: The second step is based on ATRP from the initiator-modified substrate. The initiator-modified electrode is immersed in a solution containing the monomer and the Cu(l) / Cu(ll) catalytic system. This typical and straightforward technique allows SI-ATRP polymerization to proceed at the electrode. This step is illustrated below:

[0270] [Chem25]

[0271] 5.2 Step 1: Example of initiator layer preparation on a glassy carbon electrode

[0272] Bromide-terminated substrates were obtained by electrochemical oxidative grafting of 2-bromoethylamine onto a glassy carbon electrode (GCE). Grafting was performed by cyclic voltammograms in aqueous solution containing 0.005 M 2-bromoethylamine and 0.1 M LiCICU, at 0.5 to 1.6 V vs SCE for 20 cycles. After electrochemical modification, the substrates were thoroughly rinsed with water and then sonicated.

[0273] 5.3 Step 2: Example of polymerization by the SI-ATRP procedure

[0274] 2 mM of monomer (compound 2) in acetone was added to a dry Schlenk flask, along with the pentamethyldiethylenetriamine ligand (PMDETA, 1.2 pL). The catalyst, CuCl₂ (4 pM), and the deactivator, CuCl₂ (1.4 pM), were then introduced, followed by two additional freeze-pump-out cycles. The initiator-modified electrodes were immersed in the reaction mixture under argon flow. The SI-ATRP was carried out at 50 °C for 30 minutes. The electrode was then rinsed with acetone and sonicated in acetone for 2 minutes. 6. Catalytic Properties

[0275] The compounds of the invention, due to the presence of the TEMPO radical, are particularly well-suited to the selective oxidation of alcohols. In particular, the compounds of the invention constitute highly promising homogeneous electrocatalysts for the oxidation of alcohols.

[0276] One example is the use of the compounds of the invention to facilitate the indirect electrochemical oxidation of 5-(hydroxy-methyl)furfural. Indeed, 5-(hydroxy-methyl)furfural is of considerable interest due to its role as a platform for the synthesis of various monomers, pharmaceutical raw materials, and fuels. In particular, the oxidation product of 5-(hydroxy-methyl)furfural, 2,5-furandicarboxylic acid (FDCA), has been proposed as an economically viable and biorenewable product to replace terephthalic acid in polymers.

[0277] Figure 7 shows the cyclic voltammogram of compound 6 (l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium) with a glassy carbon electrode in a borate buffer electrolyte (pH 9.2). Compound 6 exhibits reversible oxidation / reduction waves; it is oxidized to the oxoammonium cation (O=N +) during anodic sweep and then reduced again to the nitroxyl radical during cathodic sweep. After the addition of HMF to the electrolyte containing compound 6, the anodic current increases. This is attributed to the regeneration of the TEMPO radical following the reaction between HMF and the oxoammonium cation (Figure 6). The regeneration of the TEMPO radical can occur either by the reoxidation of hydroxylamine (-N-OH) or by the comproportionation of the oxoammonium cation (O=N + ) and hydroxylamine (-N-OH). No oxidation current of HMF is observed in the electrolyte compound according to the invention, demonstrating that unmediated oxidation of HMF is not operational under these conditions. Figure 7 shows that the oxidation of HMF can proceed via two pathways, both leading to FDCA.

[0278] The catalytic properties of other zwitterionic compounds (e.g., compound 8, l-(3-sulfonatopropyl)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium or compound 7, (l-(pentanoate)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium) were also confirmed. The catalytic properties of l-(3-sulfonatopropyl)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium appear to be less significant than those of compounds such as l-(pentanoate)-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium piperidoxyl)ethyl)imidazolium) or l-hydroxyethyl-3-(2-oxo-2-(2,2,6,6-tetramethyl-l-oxyl-4-piperidoxyl)ethyl)imidazolium.

Claims

AMENDED CLAIMS received by the International Bureau on March 3, 2026 (03.03.2026) 1. Multifunctional electroactive compound derived from alkyl (C1-c5)imidazole 2,2,6,6-tetramethylpiperidine-l-oxyl, which is magnetic and has acid-base properties capable of receiving / donating a proton and / or zwitterion and / or bicationic, and which has the general formula (I): in which, concerning the cation, the <n<5 et R est sélectionné parmi les groupes suivant : un alkyle sulfonate en C1-C5, un alkyle carboxylate en C1-C5, un hydroxyalkyle en C1-C5, une alkyle amine en C1-C5, un alkyle triméthylammonium en C1-C5ou and in which A" is at least one anion derived from an acid.

2. A multifunctional magnetic electroactive compound according to claim 1, characterized in that R is selected from the following groups: a C1-C5 alkyl sulfonate or a C1-C5 alkyl carboxylate, giving the multifunctional electroactive compound acid-base and zwitterion functions 3. A multifunctional magnetic electroactive compound according to claim 1, characterized in that R is selected is AMENDED SHEET (ARTICLE 19) the compound being a zwitterion.

4. A multifunctional magnetic electroactive compound according to claim 1, characterized in that R is a C1-C5 alkyl amine, giving the multifunctional electroactive compound acidic and basic functions.

5. A multifunctional magnetic electroactive compound according to claim 1, characterized in that R is a C1-C5 trimethylammonium alkyl making the compound bicationic.

6. A multifunctional magnetic electroactive compound according to claim 1, characterized in that R is a C1-C5 hydroxyalkyl giving the multifunctional electroactive compound acidic and basic functions.

7. A multifunctional electroactive compound according to any one of claims 1 to 6, characterized in that at least one anion derived from a protic acid is selected from chloride, bromide, iodide, bistriflimidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, or mixtures thereof.

8. Magnetic multifunctional electroactive compound according to any one of the claims 1 to 7, the cation being selected from the following compounds: AMENDED SHEET (ARTICLE 19) AMENDED SHEET (ARTICLE 19) 9. Electro-active ionic liquid comprising as a cation a compound of formula (I) (O in which, with respect to the cation, l≤n≤5 and R is selected from the following groups: a C1-C5 alkyl sulfonate, a C1-C5 alkyl carboxylate, a C1-C5 hydroxyalkyl, a C1-C5 alkyl amine, a C1-C5 akyl trimethylammonium -or and in which A" is at least one anion derived from an acid.

10. Electroactive protic ionic liquid according to claim 9 in which l≤n≤5 and A" is selected from the following anions: bistrifli imidide (TFSI), triflate, citrate, acetate, hydrogen sulfate, dihydrogen phosphate, chloride, bromide, iodide or mixtures thereof. AMENDED SHEET (ARTICLE 19) 11. Use of the multifunctional electroactive compound according to any one of claims 1-8, as an electrocatalyst in an electrochemical oxidation reaction.

12. Use of the multifunctional electroactive compound according to claim 11, wherein the electrocatalyst is entirely made up of organic compounds, preferably the electrocatalyst does not contain any metallic atoms.

13. Use according to any one of claims 11 to 12, characterized in that the electrochemical oxidation reaction is an oxidation of a compound comprising at least one alcohol function.

14. Use according to any one of claims 11 to 13 characterized in that the electrochemical oxidation reaction is an indirect oxidation of 5-(hydroxy-methyl)furfural.

15. Use according to the preceding claim in the production of 2,5-furandicarboxylic acid.

16. Use of the multifunctional electroactive compound according to any one of claims 1-8, for the electrochemical storage of energy, carried out for example in a supercapacitor, a battery, a symmetric battery, a supercapacitor battery, an organic battery, a redox flow battery comprising the electrochemical system.

17. Use of synthon (alkyl (C1-C5) imidazole 2,2,6,6-tetramethylpiperidine-l-oxyl) of formula (III): to produce the compound according to any one of claims 1 to 8. AMENDED SHEET (ARTICLE 19)

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