bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anodic Cyclization Reactions and an Approach to the Chrysosporazine Family of Natural Products
Authors: Moeller Kevin D , Medcalf Zachary , Wu Tiandi 
Published: August 2024

Electrochemistry has long offered new opportunities for the construction of biologically relevant molecules. Many of these opportunities are based on the ability that electrochemistry provides for reversing the polarity of known functional groups. For example, consider the brief retrosynthetic analysis shown in the Scheme below. The analysis proposes a route to the Chrysosporazine family of natural products (specifically Chrysosporazine D in this case) from readily available amino acid and lignin derived starting materials. The Chrysosporazines are efflux inhibitors that improve the effectiveness of chemotherapy agents.1 The plan calls for a coupling of the two starting materials to afford a cyclization substrate. However, the proposed cyclization reaction would combine a nucleophilic amide nitrogen with a nucleophile electron rich styrene derivative. In principle, an anodic oxidation reaction can solve this issue by either converting the amide nitrogen into a radical or oxidizing the styrene derivative to form a radical cation. Either mode would effectively reverse the polarity of one of the nucleophilic groups and allow for the cyclization.
Previous efforts examining these cyclizations have focused on the generation of a N-radical intermediate.2 Yet while these efforts have been very successful, they require the presence of a phenyl ring on the amide nitrogen in order to lower its pKa. This is essential for the formation of an amide anion that is in turn oxidized to the desired N-radical. Such a plan is not compatible with the synthesis of the Chrysosporazines that simply do not have a phenyl ring on the nitrogen of the amide. Placing one there would prevent the intramolecular cyclization. So, how can this problem be resolved?
There are two possible answers to this question. One involves a change in the overall strategy that converts the amide into an electron-rich olefin equivalent that can be oxidized to from a radical cation. The second involves finding an alternative method for dropping the pKa of the amide so that the anion and subsequent N-radical can still be made. In the chemistry to be discussed, both strategies will be examined and the propensity for the cyclic product to undergo over-oxidation shown to be the determining factor for which pathway is preferred; a preference that has led to a new approach to N-based radical cyclizations.
1. Elbanna, A. H., Khalil, Z. G., Bernhardt, P., V., Capon, R. J. Org. Lett.
2019,
21, 8097–8100.
2. Xiong, P.; Xu, H-C. Acc. Chem. Res. 2019, 52, 3339-3350.

Figure 1
Electrochemical and Spectroscopic Investigations of Bismuth(III) Pharmaceuticals with L-Glutathione
Authors: Cheek Graham , Dierickx Abram 
Published: August 2024

Due to the importance of L-cysteine in the human system, the interaction of metals with this amino acid are worthy of investigation by various methods. In this laboratory1, we have investigated the interaction of bismuth(III) compounds with L-cysteine by both cyclic voltammetry and UV-VIS spectroscopy in an attempt to understand the role of bismuth in treating gastrointestinal maladies.2 The addition of bismuth(III) compounds to solutions of L-cysteine causes a negative potential shift for bismuth(III) reduction as an indication of complex formation between bismuth(III) and L-cysteine. This interaction is also evident by the appearance of a UV-VIS spectroscopic band at 340 nm (Bi-sulfur bond). Even at low pH values (pH 1.0), electrochemical studies show evidence of some kind of interaction even when there is no 340 nm band. These investigations have been conducted at pH 1.00 and 3.00 to simulate conditions in the human stomach and at pH 7.40 MOPS [(3-N-morpholino)propanesulfonic acid] to simulate general physiological conditions, in particular the intestinal tract. Recent work has involved extension of this work to L-glutathione, a tripeptide incorporating L-cysteine, under similar conditions. As might be expected, these interactions are considerably more complicated than those involving L-cysteine. As an example, there is a considerable positive potential shift for the reduction of bismuth(III) citrate in the presence of L-glutathione on the first and second voltammetric sweeps at gold and glassy carbon electrodes. This behavior evidently reflects the rather long (several seconds) time required for the re-formation of the bismuth complex with L-glutathione after its reductive ligand (L-glutathione) loss during bismuth(III) reduction on the first sweep. In addition, there is evidence of a film buildup on the electrode surface as observed by peak current increases during multiple potential sweeps. These observations are planned for inclusion in this symposium presentation.
References

T. Cheek and D. Peña, J. Electrochem. Soc.,
167, 155522 (2020)

Li, R. Wang, and H. Sun, Acc. Chem. Res.,
52, 216 (2019).
Electrochemical Quantification of Tobramycin Retention in Pseudomonas Aeruginosa as Antimicrobial Susceptibility Indicator
Authors: Lopes Luma Clarindo , Lima Dhésmon , Hayat Muhammad , Li Yanqi , Kumar Ayush , Kuss Sabine 
Published: August 2024

The emergence and spread of bacterial resistance to antibiotics has developed into one of the most challenging threats to public health. Antibiotic susceptibility tests (ASTs) for bacterial infections are now essential, because they provide guidance for physicians in the selection of antibiotics, to which bacteria will respond. Most current AST methods require long periods of time, because of bacterial growth and incubation, leading to a prolonged and overuse of broad-spectrum antibiotics. Thus, there is a growing demand for methods and technologies that enable rapid antibiotic susceptibility assessment. Due to advantages related to cost-effectiveness, rapid response time and high sensitivity,
electrochemical detection methods are promising analytical tools that can successfully quantify antibiotic uptake and retention in clinically relevant bacterial strains. This study presents the electroanalytical quantification of tobramycin (TOB) retention in susceptible and resistant bacterial strains of Pseudomonas aeruginosa. The electrochemical behavior of TOB was characterized by voltammetry, identifying redox potentials, the current dependence on pH conditions, and the detection limit at unmodified glassy carbon electrodes. The presented methodology was able to distinguish between susceptible and resistant bacterial strains, and is also capable of identifying varying degrees of resistance against TOB. The presented approach detects the immediate interaction of bacteria with an antibiotic, without the need of complex and cost-intense equipment related to genomic testing methods
Microelectrode-Based Diffusivity Measurements of Hydrogen in Molten 2LiF-BeF2
Authors: Pickarski Timothy Ryan , Chen Claire Tianyi , Smith Eric David , Scarlat Raluca O. , Su Guanyu 
Published: August 2024

Detailed knowledge of the mass transport behavior of hydrogen isotopes in molten 2LiF-BeF2 salt (FLiBe) is essential to the design of new nuclear fusion technologies that make use of this molten salt to breed tritium to fuel the fusion reaction. However, typical studies of hydrogen transport using macroelectrodes are limited to solely measuring the permeability of an analyte—a property defined as the product of concentration squared and diffusivity. This challenge necessitates the development of microelectrodes capable of dynamically measuring diffusion coefficients when concentrations are variable. Unlike macroelectrodes, microelectrodes can measure diffusivity and concentration independently due to a steady-state current proportional to the product of diffusivity and concentration captured in addition to the Cottrellian current response.
This steady-state current is established due to a continuously expanding diffusion layer from the electrode that cannot expand indefinitely within finite experimental setups. Therefore, COMSOL Multiphysics simulations mirroring experimental conditions were performed to validate the analytical mass transport model based on the solution of Fick’s Second Law in radial coordinates. These simulations employed a 2D axisymmetric model to examine the conditions under which the infinite bulk solution approximation is valid, confirming that our electrode design would yield true steady-state current responses indicative of radial diffusion.
Platinum microelectrodes developed in this study served a dual purpose: they not only addressed previous limitations in high-temperature molten salt experimentation but also enabled dynamic measurements of both the diffusion coefficient and concentration of hydrogen in molten FLiBe introduced by lithium hydride. Square wave voltammetry and chronoamperometry were performed on a three-electrode cell using a platinum working microelectrode, a tungsten counter electrode, and a Ni/Ni2+ thermodynamic reference electrode. The successful measurement of hydrogen diffusivity in these experiments not only offers essential insights into molten FLiBe behavior but also sets the stage for future investigations into the effects of redox conditions, impurities, and equilibration time on tritium within nuclear fusion reactors.
Proton Transport in Aqueous Phosphoric, Sulfuric, and Nitric Acids: An Ab Initio Study
Authors: Zhu Zhenghao , Popov Ivan , Sokolov Alexei P. , Paddison Stephen J. 
Published: August 2024

Proton transport plays a pivotal role in various electrochemical processes and technologies. It occurs through two primary mechanisms: the vehicular mechanism where a protonic defect moves with the aid of a molecular entity; and the ‘Grotthuss mechanism’ where a proton diffuses by being transferred between host molecules via hydrogen bonds. Recently, results from ab initio molecular dynamics (AIMD) simulations combined with dielectric spectroscopy, light, and quasielastic neutron scattering revealed that protons in neat phosphoric acid indeed move by surprisingly short jumps (~0.5-0.7 Å)1,2. In the present work, we continue to delve into the solvation and transport of protons in aqueous acid using AIMD simulations.
Aqueous systems of phosphoric acid (PA), sulfuric acid (SA), and nitric acid (NA) were examined at two different ratios of acid to water 1:1 and 1:3 to understand the similarities and differences in proton transport mechanisms in these aqueous acids. The solvation structure of H3O+ in these acid solutions resembles that in the slightly acidic water but varies in the strength of hydrogen bonds formed with the acid molecules. Our results demonstrate that the strong hydrogen bonds between the PA molecules are slightly influenced by the presence of water molecules. Furthermore, the simulations reveal that H3O+ diffuses significantly faster in the aqueous PA systems than in the solutions of either SA or NA due to the assistance of PA molecules. Proton transfer events in the process of H3O+ transport show that the acid molecule can accept a proton from H3O+, either enhancing the H3O+ diffusion by shuttling a proton through a collective proton hopping or impeding it via rattling. The shuttling event significantly contributes to the H3O+ diffusion in aqueous PA, rarely occurring in the aqueous SA and never in the aqueous NA. Moreover, decomposition of H3O+ diffusion into vehicular and structural diffusion components indicates that the higher diffusion in aqueous PA is primarily due to the structural mechanism aided by the PA molecules. In the aqueous NA systems, however, the vehicular diffusion is dominant at low water contents, while increasing water content enhances the structural diffusion via connected hydrogen bonds between the water molecules. These findings shed light on the role of acid molecules in proton transport within their aqueous solutions, advancing our understanding of these fundamental mechanisms.

References:

Popov, I., Zhu, Z., Young-Gonzales, A.R., Sacci, R. L., Mamontov, E., Gainaru, C., Paddison, S. J., and Sokolov, A. P. Search for a Grotthuss Mechanism through the Observation of Proton Transfer. Commun. Chem.
6, 77 (2023).

Zhu, Z., Popov, I., Sokolov, A. P., and Paddison, S. J. Mechanistic Insights into Proton Transport in Pure and Aqueous Phosphoric Acid,
In ECS Meet. Abstr.
MA2022-02,2178 (2022).
Modeling Interfacial Proton-Coupled Electron Transfer Reactions Involving Imidazolium Proton Donors
Authors: Bagbudar Zeynep , Warburton Robert 
Published: August 2024

Proton-coupled electron transfer (PCET) is an elementary reaction that plays a pivotal role in various electrochemical energy conversion and storage processes. PCET reactions involving nonaqueous proton donors are of interest for applications in energy storage such as redox flow batteries, as well as in CO2 and O2 reduction catalysis. Yet, there remains much to be understood about the molecular reactivity of these systems. In this talk, I will describe periodic density functional theory (DFT) studies of interfacial PCET reactions involving different imidazolium proton donors on Pt(111) electrode surfaces.
The imidazole conjugate bases adsorb strongly to the electrode surface; however, this adsorption behavior varies with isomers that feature distinct proton positions and with different functional substituent groups. Because the adsorption of imidazole conjugate bases could affect reactivity, these models are used as a foundation to understand the intrinsic PCET kinetics of these systems. The Volmer and Heyrovsky steps of hydrogen evolution reaction are two of the most basic heterogeneous electrochemical PCET reactions and are therefore chosen as model interfacial PCET reactions in this study. Potential-dependent reaction energies and activation barriers are calculated using the charge extrapolation method, where the electrode potential is tuned by modifying proton coverage for different-sized unit cells. This approach is used to develop relationships between PCET reaction thermodynamics and kinetics through Brønsted–Evans–Polanyi (BEP) relationships for different imidazoles, where BEP slopes are analogs to charge transfer coefficients in the Butler–Volmer equation. Investigating reaction parameters influencing charge transfer kinetics at the electrode-electrolyte interface is crucial for designing efficient energy storage systems, impacting overall device performance. These studies show trends in the kinetic behavior of different functionalized imidazoles, which can aid in the design of catalytic and energy storage systems.
Quantifying Aging-Induced Irreversible Volume Change of Porous Electrodes
Authors: Garrick Taylor R. , Miao Yong , Macciomei Eric , Fernandez Miguel , Weidner John W. 
Published: August 2024

Automotive manufacturers are working to improve cell and pack design by increasing their performance, durability, and range. One of the critical factors to consider as the industry moves towards materials with higher energy density is the ability to consider the irreversible volume change characteristic of the accelerated SEI layer growth tied to the large volume change and particle cracking typically associated with active material strain. Here, we add to a previously developed mechano-electrochemical model[1-8] to more practically understand the impact of irreversible volume change, primarily assigned to SEI layer growth. As the time from initial design to manufacture of electric vehicle is decreased in order to rapidly respond to consumer demands and widespread adoption of electric vehicles, the ability to link aging and volume change to end of life vehicle requirements using virtual tools is critical.[9] In this study[10], we apply a model to determine the irreversible volume change at the electrode and cell level, allowing for virtual design iterations to predict the volume change at battery cell aged states, and probe possible changes in the SEI layer over life.
References
1. T. R. Garrick, K. Kanneganti, X. Huang and J. W. Weidner, J Electrochem Soc, 161, E3297 (2014).
2. T. R. Garrick, Y. Dai, K. Higa, V. Srinivasan and J. W. Weidner, ECS Transactions, 72, 11 (2016).
3. T. R. Garrick, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3552 (2017).
4. T. R. Garrick, K. Higa, S.-L. Wu, Y. Dai, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3592 (2017).
5. D. J. Pereira, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 166, A1251 (2019).
6. D. J. Pereira, M. A. Fernandez, K. C. Streng, X. X. Hou, X. Gao, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 167, 080515 (2020).
7. D. J. Pereira, A. M. Aleman, J. W. Weidner and T. R. Garrick, J Electrochem Soc, 169, 020577 (2022).
8. T. R. Garrick, M. A. Fernandez, M. Verbrugge, C. Labaza, R. Mollah, B. J. Koch, M. Jones, J. Gao, X. Gao and N. Irish, J. Electrochem. Soc., 170 060548 (2023)
9. T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, J. Electrochem. Soc., 170 113502 (2023)
10. T. R. Garrick, Y. Miao, E. Macciomei, M. Fernandez and J. W. Weidner, J Electrochem Soc, 170, 100513 (2023).
Modeling the Impact of Microstructure Variation on Charging Capability in Lithium-Ion Batteries
Authors: Teel Hunter , Garrick Taylor R. , Lopata Joseph Steven , Wang Fengkun , Zhang Han , Zeng Yangbing , Shimpalee Sirivatch 
Published: August 2024

Battery models can be used to predict conditions ripe for lithium metal plating in the anode during rapid charging. One common procedure is to simulate a rapid charge using a pseudo-two-dimensional (P2D) model and determine if and when the minimum local potential reaches 0.0 V with respect to metallic lithium in the anode. This normally occurs at higher states of charge during a DC fast charging or rapid regenerative charging event. However, we have recently determined that three-dimensional (3D) models, while broadly agreeing with P2D results, demonstrate much variation in the in-plane and through plane direction, which P2D models cannot resolve. Because P2D models employ effective medium approximations, any “local” value in the P2D space along the through-plane coordinate represents an average across a slice of the domain. Therefore, it may be insufficient to use minimum anode potentials from P2D models as indicators of local plating and may only be representative of global lithium plating onset.
The results of rapid-charge 3D microstructure simulations are compared to P2D results. This allows us to verify whether rapid charging induces negative local potentials at the anode active material surface that are left undetected in a P2D model. The expected result implies that the 3D microstructure model is necessary to predict the onset of lithium plating. We then extend our previous study to look at the impact of design changes on the microstructure performance, and then link the microstructure performance changes to performance metrics at the battery cell, module, pack, and vehicle level. Finally, the impact of variation in the microstructure domain considering particle size variation is quantified to understand tolerances that may be necessary when developing charging schemes.
References:
1. J. S. Lopata, T. R. Garrick, F. Wang, H. Zhang, Y. Zeng and S. Shimpalee, J Electrochem Soc, 170, 020530 (2023).
2. T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, J. Electrochem. Soc., 170 113502 (2023)
(Keynote) Unified Quantum Theory of Electrochemical Kinetics Based on Coupled Ion-Electron Transfer
Authors: Bazant Martin Z. 
Published: August 2024

A general theory of coupled ion–electron transfer (CIET) is presented, which unifies quantum kinetics of electron transfer (ET) with classical kinetics of bond-breaking ion transfer (IT) in a general framework of non-equilibrium thermodynamics [1]. In the limit of large reorganization energy, the theory predicts Marcus kinetics of “electron-coupled ion transfer” (ECIT). In the limit of large ion-transfer energies, the theory predicts generalized Butler–Volmer kinetics of “ion-coupled electron transfer” (ICET), where the charge transfer coefficient and exchange current are connected to microscopic properties of the electrode/electrolyte interface. In the ICET regime, the reductive and oxidative branches of Tafel’s law are predicted to hold over a wide but finite range of overpotentials, bounded by the ion-transfer energies for oxidation and reduction, respectively. The probability distribution of transferring electron energies in CIET smoothly interpolates between a shifted Gaussian distribution for ECIT (as in the Gerischer–Marcus theory of ET) to an asymmetric, fat-tailed Meixner distribution centered at the Fermi level for ICET. The latter may help interpret asymmetric line shapes in x-ray photo-electron spectroscopy (XPS) and Auger electron spectroscopy (AES) for oxidized metal surfaces in terms of shake-up relaxation of the ionized atom and its image polaron by ICET. In the limit of large overpotentials, the theory predicts a transition to inverted Marcus ECIT, leading to a universal reaction-limited current for metal electrodes, dominated by barrierless quantum transitions. Uniformly valid, closed-form asymptotic approximations are derived that smoothly transition between the limiting rate expressions for ICET and ECIT for metal electrodes, using simple but accurate mathematical functions. The theory is applied to lithium intercalation in lithium iron phosphate (LFP) and found to provide a consistent description of the observed current dependence on overpotential, temperature and concentration, learned from x-ray images [2]. CIET theory thus provides a critical bridge between quantum electrochemistry and electrochemical engineering.
[1] M. Z. Bazant, Unified quantum theory of electrochemical kinetics by coupled ion-electron transfer, Faraday Discussions 246, 60-124 (2023).
[2] H. Zhao, H. D. Deng, A. E. Cohen, J. Lim, Y. Li, D. Fraggedakis, B. Jiang, B. D. Storey, W. C. Chueh, R. D. Braatz, and M. Z. Bazant, Learning heterogeneous reaction kinetics from X-ray movies pixel-by-pixel, Nature 621, 289-294 (2023).

Figure 1
(Invited) Probing Electrochemical Interfaces in Catalytic and Energy Materials and Process Using Operando Soft X-Ray Spectroscopy
Authors: Guo Jinghua 
Published: August 2024

Advanced energy technology arises from the understanding in fundamental science, thus rest in large on in-situ/operando characterization tools for observing the physical and chemical interfacial processes. Synchrotron based X-ray spectroscopic techniques offers unique characterization in many important energy materials of energy conversion, energy storage and catalysis in regards to the functionality, complexity of material architecture, chemistry and interactions among constituents within. However, it is challenging to reveal the real mechanism of the chemical processes.
In the operando soft X-ray spectroscopy characterization of interfacial phenomena in energy materials and devices, it has been found that the microstructure and composition of materials as well as the microstructure evolution process have a great influence on performances in a variety of fields, e.g., energy conversion and energy storage materials, chemical and catalytic processes. This presentation will show how to best use the in-situ/operando soft X-ray spectroscopy characterization techniques, including soft x-ray absorption spectroscopy (XAS) and resonant inelastic soft X-ray scattering (RIXS) to investigate the real electrochemical mechanism during the operation. The experimental results show how in-situ/operando soft X-ray spectra characterization techniques uncover the phase conversion, chemical and environmental change of elements and other very important information of solid/gas and solid/liquid interfaces in real time, thus further enhance the understanding of real reaction mechanism.