bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Tetrabutylammonium Tri(1,1,1,3,3,3-hexafluoro-2-propanol)-Coordinated Fluoride and Its Application to Anodic Fluorination
Authors: Mochizuki Aika , Homma Haruka , Kitajima Nobutaka , Tajima Toshiki 
Published: December 2024

Organofluorine compounds are widely used in pharmaceuticals, agrochemicals, and functional materials due to their specific properties. However, organofluorine compounds are rarely found in nature. Therefore, organofluorine compounds must be synthesized using fluorinating agents. While Hydrogen fluoride (HF) is the most typical nucleophilic fluorinating agent, it is toxic and corrosive. Furthermore, HF is a gas at room temperature, making it difficult to handle in the ordinary laboratory. On the other hand, potassium fluoride (KF) is one of the safest and cheapest fluorinating agents, but KF is insoluble in most organic solvents. In contrast, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) dissolves KF at high concentrations.
Tetrabutylammonium fluoride (TBAF) is a highly reactive fluorinating agent that is soluble in organic solvents. However, preparation of anhydrous TBAF is difficult, because TBAF readily forms hydrates due to its high hygroscopicity. The reaction of tetrabutylammonium cyanide with hexafluorobenzene is one of the most promising methods for the synthesis of TBAF. On the other hand, TBAF-alcohol complexes such as TBAF(t-BuOH)4 have been reported as fluorinating agents with low hygroscopicity. With these facts in mind, we investigated the synthesis of TBAF from KF based on the ion exchange reaction between KF and tetrabutylammonium bromide (TBABr) in HFIP in this work.
First, TBAF was synthesized by the ion exchange reaction between KF and TBABr in HFIP. 1H and 19F NMR measurements of the obtained product revealed that it is not TBAF but TBAF(HFIP)3 with three molecules of HFIP coordinated to TBAF. The TBAF(HFIP)3 was obtained in excellent yield without complicated operations. Next, anodic fluorination of a sulfide was investigated using TBAF hydrate or TBAF-alcohol complexes. As results, the corresponding fluorinated product was obtained in good yield only when TBAF(HFIP)3 was used. These results may be due to the low nucleophilicity and oxidation resistance of HFIP. From these results, TBAF(HFIP)3 would be a promising new supporting electrolyte and fluorinating agent.

Figure 1
Transition-Metal-Catalyst-Free Electroreductive Hydroarylation of Alkenes with Aryl Halides
Authors: Yamamoto Kosuke , Arita Kazuhisa , Shiota Masashi , Kuriyama Masami , Onomura Osamu 
Published: December 2024

The radical hydroarylation of alkenes provides synthetically valuable linear alkylarenes with high anti-Markovnikov selectivity. Aryl halides are ideal radical precursors owing to their chemical stability and wide commercial availability. Over the past few decades, electrochemistry has proven to be an convenient approach for accessing open-shell intermediates through a single-electron transfer process, and the electroreduction of aryl halides has been demonstrated as a powerful method to generate aryl radical species.1 Despite recent progress in the development of aryl radical-involved electroreductive coupling reactions, the reported intermolecular radical hydroarylation of alkenes without transition-metal catalysts still has some drawbacks, such as the use of a Hg pool cathode and liquid NH3 solvent.2

Hearin, we report a transition-metal-catalyst-free elctroreductive hydroarylation of alkenes using aryl halides as radical precursors. The hydroarylation was performed in acetonitrile using an undivided cell equipped with an Al anode and a Pt cathode, and the use of 1,3-dicyanobenzene as a redox mediator under visible-light irradiation enabled the desired transformation to proceed with high efficiency. Electron-deficient (hetero)aryl chlorides and electron-rich aryl iodides successfully reacted with various Michael acceptors and styrene derivatives, providing a variety of linear alkylarenes in good to high yields. Mechanistic investigations indicated that this transformation would proceed through a reductive radical-polar crossover pathway.
(1) Xiang, H.; He, J.; Qian, W.; Qiu, M.; Xu, H.; Duan, W.; Ouyang, Y.; Wang, Y.; Zhu, C. Molecules
2023, 28, 857.
(2) Chami, Z.; Gareil, M.; Pinson, J.; Savéant, J.-M.; Thiébault, A. J. Org. Chem. 1991, 56, 586–595.

Figure 1
Synthesis of Thienoacenes By Electrochemical Double C–S Cyclization Promoted By a Halogen Mediator
Authors: Mitsudo Koichi , Nagahara Takuya , Suga Seiji 
Published: December 2024

Thienoacenes, sulfur-containing π-conjugated molecules, have been widely used as active compounds for organic materials such as organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). In particular, thienoacenes bearing thieno[3,2-b]thiophene (TT) moieties, such as [1]benzothieno[3,2-b][1]benzothiophene (BTBT), dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT), and dibenzo[d,d’]thieno[3,2-b;4,5-b’]dithiophene (DBTDT), exhibited excellent OFET properties. While there have been many reports on the synthesis of thienoacenes, one of the most efficient ways to synthesize such thienoacenes is multiple C–S bond formation in one step. Because unprotected S–H bonds are easily oxidized to S–S bonds, protection of the S atom is often required and methyl protection has been used widely. For instance, Takimiya and co-workers reported the reaction of bis(naphthalenyl)ethene bearing two methylsulfanyl groups with an excess amount of iodine to afford a highly π-expanded thienoacene such as DNTT.1 While this strategy is efficient for constructing a BTBT skeleton, an excess amount of iodine was required, and highly π-extended substrates could only be applicable. Therefore, developing an efficient method for the one-step construction of multiple C–S bonds is still challenging, and it should be a powerful tool to construct thienoacenes efficiently.
We recently reported an electrochemical dehydrogenative C-S bond formation to synthesize thienoacenes.2 This time, we developed a more straightforward method to construct thienoacenes: an electrochemical approach for synthesizing BTBT derivatives from S-protected bis(o-sulfanylphenyl)acetylene derivatives. In the presence of Bu4NBr as a halogen mediator, electrochemical double C–S cyclization proceeded smoothly. Using the Bu4NBr as a mediator is important, and only a trace amount of the desired product was obtained without Bu4NBr. Appropriate protection was also essential for the reaction. While S-Me or S-p-methoxybenzyl (PMB) protected bis(o-sulfanylphenyl)acetylenes did not afford BTBT and bromocyclized products were obtained, the electrochemical reaction of S-MOM protected bis(o-sulfanylphenyl)acetylenes afforded BTBT derivatives selectively. Adding H2O was required for efficient reaction progression, which works as a sacrificial agent and a trapping agent for the eliminated MOM group. Various symmetrical and asymmetrical BTBT derivatives were obtained under the optimal conditions. The S-MOM protection strategy is also effective for the electrochemical synthesis of a more π-expanded thienoacene, such as DBTDT.
(1) Yamamoto, T.; Takimiya, K. J. Am. Chem. Soc.
2007, 129, 2224–2225.
(2) Mitsudo, K.; Matsuo, R.; Yonezawa, T.; Inoue, H.; Mandai, H.; Suga, S. Angew. Chem., Int. Ed.
2020, 59, 7803–7807.

Figure 1
Autonomous and Closed-Loop Exploration and Optimization of Bioelectrocatalytic Systems
Authors: Pence Michael A. , Boucher Dylan G. , Nguyen Zachary A , Rodriguez Lopez Joaquin , Minteer Shelley D. 
Published: December 2024

Automated electrochemistry platforms provide a pathway for speeding up the discovery and optimization of electrochemical systems, especially when a broad range of molecules and reaction conditions must be explored.1-3 Additionally, incorporation of machine learning enables closed-loop optimization campaigns, where the obtained experimental data guides the selection of the next set of experimental parameters to test. This type of autonomous exploration is ideally suited for the study of enzyme electrocatalysis, as the combinatorics of different enzymes, substrates, and redox mediators creates a prohibitively large parameter space. Even within a single enzyme class, mutations to the amino acid sequence can significantly impact rate, function, and selectivity of the catalyzed reaction. Thus, an automated electrochemical platform that enables rapid sampling both reaction parameters and amino acid sequence space would enable discovery of new, non-native enzymatic reactions.
In this work we use an open source and modular automated electrochemistry platform to study enzyme electrocatalysis in several common bioelectrocatalytic systems, such as glucose oxidase, glucose dehydrogenase, and aldehyde dehydrogenase. We use automated cyclic voltammetric substrate titration experiments (Figure 1) to gain insight into the kinetics of the redox-mediated enzymatic catalysis and demonstrate the reaction conditions in which traditional mechanistic simplifications, like Michaelis-Menten, break down. Additionally, the automated electrochemistry platform allows for the rapid screening of different substrate molecules, enabling the quantification of substrate promiscuity in these enzymatic catalysts. We show how Bayesian Optimization can be incorporated into our workflow to autonomously tune solution parameters to promote increased reaction rates. These studies demonstrate the power of autonomous electrochemistry for understanding and screening biocatalytic systems and represent a significant step towards totally machine-guided biocatalyst evolution.
[1] Oh, I. ; Pence, M. A.; Lukhanin, N.; Rodriguez, O.; Schroeder, C. M.*; Rodriguez-Lopez, J.*, “The Electrolab: An open-source, modular platform for automated characterization of redox-active electrolytes” Device,
2023,
1, 5, 100103
[2] Rodriguez, O.; Pence, M. A.; Rodriguez-Lopez, J.*, “Hard Potato: An Open Source Python Library to Control Commercially Available Potentiostats and Automate Electrochemical Experiments” Anal. Chem.,
2023,
95, 4840–4845
[3]Pence, M. A.; Rodriguez, O.; Lukhanin, N.; Schroeder, C. M.*; Rodriguez-Lopez, J.*, “Automated Measurement of Electrogenerated Redox Species Degradation Using Multiplexed Interdigitated Electrode Arrays”, ACS Meas. Sci. Au,
2023,
3, 62–72

Figure 1
(Invited) Improving Low-Temperature Lithium-Ion Battery Performance through 3D Structure-Controlled Anodes with Optimized Charge Storage Mechanisms
Authors: Lee Michael J , Lee Kyungbin , Ryu Kun , Lee Seung Woo 
Published: December 2024

The performance of lithium (Li)-ion batteries (LIBs) significantly decreases at low temperatures, primarily due to the slow diffusion of Li ions within the graphite anode. This issue often necessitates the use of complex thermal control systems to safeguard the batteries, enhancing their cost, mass, and volume, especially under extreme conditions. Here, we introduce both structure-controlled graphene and graphite composite anodes, which employ controlled charge storage mechanisms to accelerate Li-ion charge storage kinetics and maintain structural stability under low-temperature conditions. [1-3] By transitioning from layered graphite to crumpled graphene or expanded graphite (composite), we effectively utilize diffusion- and surface-controlled charge storage mechanisms. These structure-controlled anodes exhibit superior rate capability and exceptional performance at temperatures as low as -50 °C. Through comprehensive low-temperature analyses, this research provides a detailed understanding of the relationships between anode structure, charge storage mechanisms, and performance under low-temperature conditions. Our findings offer valuable insights for the development of advanced energy storage devices optimized for low-temperature operation.

References

[1] K. Lee†, M. J. Lee†, J. Lim, K. Ryu, M. Li, S. Noda, S. J. Kwon*, S. W. Lee*, Controlled Nitrogen Doping in Crumpled Graphene for Improved Alkali Metal-Ion Storage under Low-Temperature Conditions. Advanced Functional Materials, 33, 2209775, 2023.
[2] K. Ryu†, M. J. Lee†, K. Lee, S. W. Lee*, ZnO-Embedded Expanded Graphite Composite Anodes with Controlled Charge Storage Mechanism Enabling Operation of Lithium-Ion Batteries at Ultra-Low Temperatures. Energy & Environmental Materials, 0, e12662, 2023.
[3] M. J. Lee, K. Lee, J. Lim, M. Li, S. Noda, S. J. Kwon, B. DeMattia, B. Lee*, S. W. Lee*, Outstanding Low-Temperature Performance of Structure-Controlled Graphene Anode Based on Surface-Controlled Charge Storage Mechanism. Advanced Functional Materials, 31, 2009397, 2021.
Experimental Extraction of Carbon-Binder-Domain Characteristic for Simulation Purposes
Authors: Pinilla Sergio , Zanotto Franco , Dominguez Diana Zapata , Rodríguez Tomás , A. Franco Alejandro 
Published: December 2024

In the last years, there has been a substantial push in the lithium ion battery field to develop accurate electrochemical models that are capable of reproducing the response of experimental electrodes. There are myriad applications and uses of these models that range from material design to cell integration, providing means for a rational design of electrodes and cells, as well as diagnosis and prognosis tools during its life.1

Among all the models, electrode scale 3D mesoscopic electrochemical modeling approaches have gained substantial relevance due to the possibility of linking the electrochemical model with manufacturing models, creating a unique simulation pipeline that gathers all information from slurry to cell. 2

These 3D mesoscopic models count with an additional advantage compared to simpler models such as the p2D approaches, and it is the fact they account better for the microstructure, which is known to be very determinant in the electrode performance.3 These models usually consider three main domains inside the electrode, the active material, the carbon-binder domain and the pores. While the active material and its pore network have been better studied and can be more easily obtained by tomography, the carbon-binder domain and its distribution in the microstructure is harder to study 4 but extremely determinant in the properties of the electrodes.5 The carbon binder domain properties, such as its conductivity, porosity and tortuosity factor will determine the heterogeneity of the reactions happening in the electrodes. 5 However, until now, there is a lack of experimental approaches able to characterize the porosity and tortuosity factor of the carbon binder domain, and this is precisely the topic of this work. We propose a methodology to extract the characteristics of the carbon binder domain, namely its porosity and tortuosity factor, by combining electrode manufacturing, characterization and computational simulations.
Our methodology is based on the study of electrochemical impedance data over a wide matrix of cases in a systematic way using, as a proof of concept, well-characterized NMC electrodes and relating it with electrode-level simulation results.
The proposed methodology is completely general and independent of the cell chemistry, and not only provides a tool to better understand and simulate the behaviour of the carbon binder domain, but it is also demonstrated how it can be used to obtain experimental data that was not easily available before.

A. A. Franco et al., Chem.
Rev., 119, 4569–4627 (2019).

C. Liu, T. Lombardo, J. Xu, A. C. Ngandjong, and A. A. Franco, Energy Storage Materials, 54, 156–163 (2023).

T.-T. Nguyen et al., npj Comput Mater, 6, 123 (2020).

J. Landesfeind, M. Ebner, A. Eldiven, V. Wood, and H. A. Gasteiger, J. Electrochem. Soc., 165, A469–A476 (2018).

M. Chouchane and A. A. Franco, Energy Storage Materials, 47, 649–655 (2022).
Structural Evolution of Mn-Based Disordered Rock Salt Cathodes
Authors: Li Tianyu , Geraci Tullio Salvatore , Koirala Krishna Prasad , Wang Chongmin , Navrotsky Alexandra , Clement Raphaele J 
Published: December 2024

Manganese-based disordered rock salt (DRX) oxides are promising new generation lithium-ion cathode materials due to the low costs and the high theoretical capacities. Recent research has revealed that DRX compounds with high manganese content, denoted as Li1+xMnyM1-x-yO2 (where y>0.5 and M represents hypervalent d0 ions such as Ti4+ and Nb5+), undergo a gradual capacity increase over initial charge-discharge cycles. This phenomenon coincides with the development of localized domains exhibiting a spinel-like cation arrangement within the overall disordered structure, termed the "δ phase."
In my presentation, I will detail our effort on systematically investigating the structural changes occurring in manganese-based DRX compounds at various levels of lithium removal through heating. Analysis using synchrotron X-ray, neutron diffraction and 7Li solid state NMR reveals that , during the structural relaxation of delithiated DRX, lithium and manganese/titanium cations selectively migrate to different crystallographic sites within the rock salt structure, driving the observed structural rearrangements. We confirm that the structural evolution is the major factor contributing to the capacity enhancement. Furthermore, our research shows that both manganese-rich and manganese-poor DRX oxides can undergo thermal relaxation into the δ phase at delithiated states. However, the relaxation processes in DRX with different Mn content result in distinct domain structures. Calorimetry measurements and in-situ heating XRD experiments suggest that the structural relaxation exhibits a stronger thermodynamic driving force and lower activation energy for manganese-rich DRX compounds compared to manganese-poor systems. This difference explains why the observed structural evolution occurs predominantly in the former category during battery cycling.

Figure 1
(Invited) Nanostructured Positive Electrode Materials for Li-Ion Battery Applications
Authors: Yabuuchi Naoaki 
Published: December 2024

Ni-enriched layered materials are used as electrode materials of Li-ion batteries for electric vehicle applications. Stoichiometric LiNiO2 with cationic Ni3+/Ni4+ redox is the ideal electrode material, but the gradual loss of capacity at the high voltage region, associated with Ni ion migration, hinders its use for practical applications.1 Recently, the importance of non-stoichiometry and anti-site defects is discussed for LiNiO2, and highly reversible pure Ni-based layered materials without metal substitution is successfully developed through defects engineering.1

Another important target is the development of a practical and high-energy Co-/Ni-free Mn-based positive electrode material, which is necessary for the economical electric vehicles. Nanostructured Mn-based electrode materials are proposed as emerging materials for this purpose.2 However, these materials are generally synthesized by high-energy milling, which cannot be adopted for mass production. Recently, nanostructured LiMnO2 with high-energy density (~800 Wh kg–1) is successfully synthesized by using a conventional calcination reaction, which is potentially used for economical electric vehicle applications.3

To develop safe and high-energy Li-ion batteries, the use of solid electrolyte is an important strategy. Nevertheless, inevitable volume changes of electrode materials on cycling lead to the difficulty to maintain the stable interface between electrode materials and electrolyte. Recently, a nanostructured cation-disordered rocksalt oxide with a dimensionally invariable character is developed. Indeed, the excellent reversibility with solid electrolyte is achieved.5

From these results, the importance of nano-structured lithium insertion materials for practical Li-ion battery applications is discussed.

References
1) Konuma et al., and N. Yabuuchi, Energy Storage Materials, 66, 103200 (2024).
2) Kanno et al., and N. Yabuuchi, ACS Energy Letters, 8, 2753 (2023).
3) Miyaoka et al., and N. Yabuuchi, submitted
4) R. Fukuma et al., and N. Yabuuchi, ACS Central Science, 8, 775 (2022).
5) I. Konuma et al., and N. Yabuuchi, Nature Materials, 22, 225 (2023).
Electrochemical Investigations of Chlorpyrifos-Induced Toxicity Effects in Astrocytic Glutamate Regulation
Authors: Xu Kaixuan , Neely M. Diana , Guel Camilla , Cliffel David E. 
Published: December 2024

Glutamate is a major excitatory neurotransmitter in the central nervous system, and its homeostasis is critically regulated by astrocytic glutamate transporters. Dysregulation of astrocyte function has been implicated in the pathogenesis of various neurodegenerative diseases. The organophosphate pesticide chlorpyrifos (CPF) has raised significant public health concerns due to its documented neurotoxic effects, but the specific impacts of CPF on glutamate neurotransmission and metabolism within astrocytes remain poorly understood.
Here we designed and modified an electrochemical sensor to detect changes in glutamate levels following acute CPF exposure in astrocyte cultures. Our microclinical analyzer (µCA) paired with screen-printed electrodes (SPE) offers an automated sensing system that enables high-resolution monitoring of extracellular glutamate dynamics, providing insights into the effects of CPF on astrocytic glutamate regulation. Immobilized glutamate oxidase on electrode surfaces provided selective and sensitive glutamate detection. The temperature modification of electrodes through incubation (37°C) led to a nearly four-fold improvement in sensitivity (0.84±0.04 nA/µM), with low limits of detection (2.8±0.1 µM), and quantitation (9.3±0.5 µM). Our SPE detected glutamate from 1 to 600 µM which comprehends the physiological range in the brain region. These sensors were used to assess the glutamate uptake efficiency via challenging escalating concentrations of glutamate (10-200 µM) in astrocytes. Glutamate uptake was most efficient when astrocytes were exposed to 50 µM glutamate for 30min (50% net uptake). Efficiencies of glutamate uptake after 24-hour 100 µM CPF exposure were significantly diminished compared with the DMSO control.
The results shed light on the potential mechanisms by which CPF-induced disruption of astrocytic glutamate homeostasis may contribute to neurological damage and dysfunction. This work demonstrates the utility of electrochemical biosensing techniques for investigating the neurotoxicological impacts of environmental toxicants on specific cell types and neurochemical pathways. Further development of these analytical tools may aid in elucidating the complex relationships between astrocyte dysregulation, excitotoxicity, and neurodegenerative processes.