all comments addressed... For the moment

nitroxides.tex

@@ -112,7 +112,7 @@ \section{Introduction}
 	\label{fig:states}
 \end{figure}
 
-Experimental studies have demonstrated that the performance of nitroxide-based batteries is influenced by substituents \cite{sugaCathodeAnodeActivePoly2007}, solvation, and the nature of the electrolytes used \cite{armandIonicliquidMaterialsElectrochemical2009,strehmelRadicalsIonicLiquids2012,wylieIncreasedStabilityNitroxide2019b}. Understanding the interplay between the nitroxides, the solvents, and the electrolytes is therefore crucial \replaced{to}{for} the rational design of high-performance batteries. Computational studies using quantum chemical methods provide valuable insights into the crucial solvation effects, enabling the prediction and tuning of redox properties \cite{madkourComputationalMonteCarlo2018,maftoon-azadElectrochemicalStabilityWindows2021,ritaccaExperimentalTheoreticalStudy2022,esmaeilbeigHydrolysisIronIons2022,jyothirmaiChangesStructureStability2022}.
+Experimental studies have demonstrated that the performance of nitroxide-based batteries is influenced by substituents \cite{sugaCathodeAnodeActivePoly2007}, solvation, and the nature of the electrolytes used \cite{armandIonicliquidMaterialsElectrochemical2009,strehmelRadicalsIonicLiquids2012,wylieIncreasedStabilityNitroxide2019b}. Understanding the interplay between the nitroxides, the solvents, and the electrolytes is therefore crucial \replaced{to}{for} the rational design of high-performance batteries. Computational studies using quantum chemical methods \added{(QC)} provide valuable insights into the crucial solvation effects, enabling the prediction and tuning of redox properties \cite{madkourComputationalMonteCarlo2018,maftoon-azadElectrochemicalStabilityWindows2021,ritaccaExperimentalTheoreticalStudy2022,esmaeilbeigHydrolysisIronIons2022,jyothirmaiChangesStructureStability2022}.
 
 From a phenomenological perspective, two approaches can be used: at low concentrations in electrolytes, the Debye-Hückel (DH) theory \cite{kontogeorgisDebyeHuckelTheoryIts2018,silvaDerivationsDebyeHuckel2022,silvaImprovingBornEquation2024} provides an initial estimate for interactions within an ionic liquid. While improvements have been proposed over the years to better account for ion-solvent interactions, particularly by including dipole-ion \cite{silvaImprovingBornEquation2024} and quadrupole-ion interactions \cite{slavchovQuadrupoleTermsMaxwell2014,slavchovQuadrupoleTermsMaxwell2014a,coxQuadrupolemediatedDielectricResponse2021}, there have been only a few attempts \cite{matsuiDensityFunctionalTheory2013,xiaoReorganizationEnergyElectron2013,xiaoMolecularDebyeHuckelApproach2014} to incorporate DH theory into the prediction of redox potentials. There is also a limited implementation of DH theory in the polarizable continuum model \cite{cossiInitioStudyIonic1998}. 
 
@@ -596,20 +596,20 @@ \subsection{Comparison to experiment} \label{sec:exp}
 \clearpage
 \section{Conclusions and outlooks} \label{sec:conclusion}
 
-In this paper, the impact of different solute-solvent \replaced{interactions}{effects}  on the redox potentials of nitroxides has been assessed using quantum chemistry approaches, with a particular emphasis on ionic interactions. The calculation have been performed at the DFT level ($\omega$B97X-D/6-311+G*), with implicit solvation (SMD) to account for the impact of the solvent.
+In this paper, the impact of \added{structure and of}  different solute-solvent \replaced{interactions}{effects}  on the redox potentials of nitroxides has been assessed using quantum chemistry approaches, with a particular emphasis on ionic interactions\added{. From an experimental point of view, the insights provided by this work pave the way towards improved design for radical polymers}. The calculation\added{s} have been performed at the DFT level ($\omega$B97X-D/6-311+G*), with implicit solvation (SMD) to account for the \deleted{impact of the} solvent\added{. Electrolytes have been considered in the calculations, and the results have been validated against experimental results and proved reliable. From a theoretical point of view, it highlights the importance of including these effects into the computation of redox potentials}.
 
-Different families of nitroxides have been considered: 5- (P6O, APO) and 6-membered rings (P5O, IIO) containing the nitroxyl moiety, and with (IIO, APO) or without an aromatic system (P5O, P6O) in close vicinity. The impact of such structural changes as well as of substituent\added{s} on the redox potentials is largely explained by the electrostatic interaction model (Fig.~\ref{fig:dipole}) developed by Zhang and co-workers \cite{zhangEffectHeteroatomFunctionality2018}: thought the dipole interaction between the substituent and the redox center can explain, in first approximation, the variation that are observed, the inclusion of the quadrupole moment is necessary to explain the increases of both the oxidation and reduction potentials of aromatic nitroxides. Furthermore, acceptor substituents (such as \ce{NO2}) further increase both potentials. While the impact remains moderate (+\SI{0.4}{\volt}), it is hoped that this will provide design rules for future investigations. 
+\added{Concerning the structural effects, d}ifferent families of nitroxides have been considered: 5- (P6O, APO) and 6-membered rings (P5O, IIO) containing the nitroxyl moiety, and with (IIO, APO) or without an aromatic system (P5O, P6O) in close vicinity. The impact of such structural changes as well as of substituent\added{s} on the redox potentials is largely explained by the electrostatic interaction model (Fig.~\ref{fig:dipole}) developed by Zhang and co-workers \cite{zhangEffectHeteroatomFunctionality2018}\added{ and refined, then validated against calculations, in this work}: thought the dipole interaction between the substituent and the redox center can explain, in first approximation, the variation that are observed, the inclusion of the quadrupole moment is necessary to explain the increases of both the oxidation and reduction potentials of aromatic nitroxides. Furthermore, acceptor substituents (such as \ce{NO2}) further increase both potentials. \replaced{This simple, yet powerful, model provide simple design rules for future applications}{While the impact remains moderate (+0.4V), it is hoped that this will provide design rules for future investigations}.
 
-While the Born model [Eq.~\eqref{eq:born}] shows that the solvent tends to stabilize charges due to changes in the dielectric constant (especially in polar solvents), other, more subtle effects arise from solute-ion interactions caused by the presence of electrolytes. These electrolytes are found in moderate concentrations (\textit{i.e.,} \SI{0.1}{\mole\per\liter}) during the experimental measurement of redox potentials and in higher concentrations (>$\SI{1}{\mole\per\liter}$) in ionic liquids used for batteries. 
+\added{Turning to the impact of the electrolytes, w}hile the Born model [Eq.~\eqref{eq:born}] shows that the solvent tends to stabilize charges due to changes in the dielectric constant (especially in polar solvents), other, more subtle effects arise from solute-ion interactions caused by the presence of electrolytes. These electrolytes are found in moderate concentrations (\textit{i.e.,} \SI{0.1}{\mole\per\liter}) during the experimental measurement of redox potentials and in higher concentrations (>$\SI{1}{\mole\per\liter}$) in ionic liquids used for batteries. 
 Their  impact is twofold:
 \begin{inparaenum}[(i)]
 	\item at any concentration, the background of charge stabilizes charged compounds, and
 	\item at high concentrations, the formation of ion-pairs modifies the redox properties of nitroxides.
 \end{inparaenum}
-Both effects have been examined: when the charge of the compound and of the electrolyte constituents is moderate  the correction proposed by the Debye-Hückel model is sufficient. However, the formation of pairs depends on the redox state of the nitroxide and the nature of the intermolecular interactions, which goes beyond a simple pair formation model (such as the one found in Fig.~\ref{fig:ionpair}). Indeed, two positions are possible for the ion: near the redox center of the nitroxide, and closer to its substituent, if any. The ion-substituent interaction (in the second position) generally leads to more favorable complexes (especially when the molecule contains aromatic moieties). However, in acetonitrile, the interaction between the reduced form (hydroxylamine anion) and its cation, positioned near the $>$\ce{N-O-} moiety, is the strongest. This seems to be the case in other low-dielectric environments, as noted by others in an even less polar solvent (using methanol, $\varepsilon_r$ = 25, in Ref.~\citenum{wylieImprovedPerformanceAllOrganic2019a}).
-It was, however, not possible to correlate the impact of the substitution on the formation of ion-pairs, but it was noticed that the favorable interactions between \ce{N-} and \ce{C+} was systematically hampered by the nitroxyl in an axial position in P6O. This is another important design rule for future applications.
+Both effects have been \replaced{scrutinized using our improved QC methodology}{examined}: when the charge of the compound and of the electrolyte constituents is moderate  the correction proposed by the Debye-Hückel model is sufficient. However, the formation of pairs depends on the redox state of the nitroxide and the nature of the intermolecular interactions, which goes beyond a simple pair formation model (such as the one found in Fig.~\ref{fig:ionpair}). Indeed, two positions are possible for the ion: near the redox center of the nitroxide, and closer to its substituent, if any. The ion-substituent interaction (in the second position) generally leads to more favorable complexes (especially when the molecule contains aromatic moieties). However, in acetonitrile, the interaction between the reduced form (hydroxylamine anion) and its cation, positioned near the $>$\ce{N-O-} moiety, is the strongest. This seems to be the case in other low-dielectric environments, as noted by others in an even less polar solvent (using methanol, $\varepsilon_r$ = 25, in Ref.~\citenum{wylieImprovedPerformanceAllOrganic2019a}).
+It was, however, not possible to correlate the impact of the substitution on the formation of ion-pairs, but it was noticed that the favorable interactions between \ce{N-} and \ce{C+} was systematically hampered by the nitroxyl in an axial position in P6O. \replaced{Altogether, this second part provides better understanding of the interaction between nitroxides and electrolytes, again helping in designing better devices.}{This is another important design rule for future applications}.
 
-Finally, a comparison with the experiment has been performed. It results in an excellent correlation, but the impact of the corrections presented above is small in the solvents considered here (water and acetonitrile) and with the concentrations of electrolytes used experimentally. \replaced{It would be valuable to compare redox potentials measured under different conditions, such as in less polar solvents or ionic liquids. Experimental redox potentials for other nitroxides in battery-relevant environments have already been reported in the literature}{As a matter of fact, it would be interesting to compare redox potentials measured under different conditions (such as in ionic liquids)} \cite{bergnerTEMPOMobileCatalyst2014,tkachevaTEMPOIonicLiquidsRedox2020}. Another factor that should be investigated is the temperature, which would affect both the DH correction (through $\kappa$, Eq.~\eqref{eq:kappa2}) and the complexation equilibrium constant (though the entropic contribution). For example, conventional lithium-ion batteries can operate up to \SI{60}{\degreeCelsius} \cite{maTemperatureEffectThermal2018}, and ionic liquids are stable over extended temperature ranges. The modification of the dielectric constant of the solution with increasing electrolyte concentration \cite{kontogeorgisDebyeHuckelTheoryIts2018, silvaTrueHuckelEquation2022}, is another point that should be considered in future studies.
+Finally, a comparison with the experiment has been performed. It results in an excellent correlation, but the impact of the corrections presented above is small in the solvents considered here (water and acetonitrile) and with the concentrations of electrolytes used experimentally. \replaced{It would be valuable to compare redox potentials measured under different conditions, such as in less polar solvents or ionic liquids. Experimental redox potentials for other nitroxides in battery-relevant environments have already been reported in the literature}{As a matter of fact, it would be interesting to compare redox potentials measured under different conditions (such as in ionic liquids)} \cite{bergnerTEMPOMobileCatalyst2014,tkachevaTEMPOIonicLiquidsRedox2020}. Another factor that should be investigated is the temperature, which would affect both the DH correction (through $\kappa$, Eq.~\eqref{eq:kappa2}) and the complexation equilibrium constant (though the entropic contribution). For example, conventional lithium-ion batteries can operate up to \SI{60}{\degreeCelsius} \cite{maTemperatureEffectThermal2018}, and ionic liquids are stable over extended temperature ranges \cite{tkachevaTEMPOIonicLiquidsRedox2020}. The modification of the dielectric constant of the solution with increasing electrolyte concentration \cite{kontogeorgisDebyeHuckelTheoryIts2018, silvaTrueHuckelEquation2022}, is another point that should be considered in future studies.
 
 \section*{Notes}
 The author declare no competing financial interest.