bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Dual Cobalt‐Photoredox Catalytic Approach for Asymmetric Dearomatization of Indoles with Aryl Amides via C−H Activation
Authors: Das Abir , Kumaran Subramani , Ravi Sankar Harihara Subramanian , Premkumar J. Richard , Sundararaju Basker 
Published: June 2024

AbstractIn this study, we unveil a novel method for the asymmetric dearomatization of indoles under cobalt/photoredox catalysis. By strategically activating C−H bonds of amides and subsequent migratory insertion of π‐bonds present in indole as reactive partner, we achieve syn‐selective tetrahydro‐5H‐indolo[2,3‐c]isoquinolin‐5‐one derivatives with excellent yields and enantiomeric excesses of up to >99 %. The developed method operates without a metal oxidant, relying solely on oxygen as the oxidant and employing an organic dye as a photocatalyst under irradiation. Control experiments and stoichiometric studies elucidate the reversible nature of the enantiodetermining C−H activation step, albeit not being rate‐determining. This study not only expands the horizon of cobalt‐catalyzed asymmetric C−H bond functionalization, but also showcases the potential synergy between cobalt and photoredox catalysis in enabling asymmetric synthesis of complex molecules.
A Hexaarylbiimidazole‐Terarylene Hybrid: Visible‐to‐NIR‐II Absorption via Sequential Photochromic Reactions
Authors: Mutoh Katsuya , Kobayashi Yoichi , Nakashima Takuya 
Published: June 2024

AbstractA synergetic interaction between two or more photochromic chromophores has a potential to achieve advanced photochemical properties beyond conventional photochromic molecules and to realize photochemical control of complex systems using only a single molecule. Herein, we report a hybrid photochromic molecule consisting of hexaarylbiimidazole (HABI) and terarylene that exhibits multi‐state photochromism. The biphotochrome hybrid shows four‐state photochromic reaction involving sequentially proceeding photoreactions. The UV or visible light irradiation to the biphotochrome leads to the C−N bond breaking reaction of the HABI in preference to the ring‐closing reaction of the 6π‐electron system in the terarylene unit, leading to two terarylene radical molecules. The photogenerated terarylene radical further exhibits the 6π‐electrocyclization reaction by UV irradiation. The delocalized π‐radical on the closed‐ring form of the terarylene is efficient to enhance the photosensitivity to the NIR−I and ‐II region. Furthermore, a recombination reaction of radicals between the open‐ and closed‐ring isomers of terarylene affords an unprecedented photochromic dimer as a structural isomer of the initial molecule. This is a consequence of the sequential hybrid photochromic system involving the HABI and terarylene units.
Highly Stable Perovskite Oxides for Electrocatalytic Acidic NOx− Reduction Streamlining Ammonia Synthesis from Air
Authors: Guo Xuecheng , Wang Zhongliao , Gao Yuan , Zhang Chao , Zhang Shuai , Sang Shuaikang , Ma Jun , Sun Shuhui , Murzin Dmitry Yu. , Low Jingxiang , Shao Tao , Xiong Yujie 
Published: June 2024

AbstractElectrochemical nitrogen oxide ions reduction reaction (NOx−RR) shows great opportunity for ammonia production under ambient conditions. Yet, performing NOx−RR in strong acidic conditions remains challenging due to the corrosion effect on the catalyst and competing hydrogen evolution reactions. Here, we demonstrate a stable La1.5Sr0.5Ni0.5Fe0.5O4 perovskite oxide for the NOx−RR at pH 0, achieving a Faradaic efficiency for ammonia of approaching 100 % at a current density of 2 A cm−2 in a H‐type cell. At industrially relevant current density, the NOx−RR system shows stable cell voltage and Faradaic efficiency for >350 h in membrane electrode assembly (MEA) at pH 0. By integrating the catalyst in a stacked MEA with a series connection, we have successfully obtained a record‐breaking 2.578 g h−1 NH3 production rate at 20 A. This catalyst‘s unique acid‐operability streamlines downstream ammonia utilization for direct ammonium salt production and upstream integration with NOx sources. Techno‐economic and lifecycle assessments reveal substantial economic advantages for this ammonia production strategy, even when coupled with a plasma‐based NOx production system, presenting a sustainable complement to the conventional Haber–Bosch process.
Enhancing the thermal and mechanical properties of sulfonated peek fiber composites with reduced smoke density and toxicity
Authors: Gurung Dinesh , Murad Md Shafinur , Asmatulu Eylem , Gürsoy Mustafa , Bahçeci Ersin , Bakir Mete , Asmatulu Ramazan 
Published: June 2024

AbstractPolyether ether ketone (PEEK) sulfonation process is a reasonably easy but time‐consuming to manufacture composites. This study focuses on altering PEEK powder in a sulfuric acid solution via a sulfonation process to develop sulfonated PEEK (SPEEK) resin for the fiber‐reinforced thermoplastic composite manufacturing and characterization steps. In this study, about 5 wt% PEEK powder was sulfonated in 98% sulfuric acid solution for 12 h at 65°C. The water bath technique was used for the precipitation process to obtain the SPEEK polymer. After proper washing and drying, the SPEEK matrix (resin) was obtained by dissolving it in dimethylformamide in a ratio of 1:2. This resin solution was then used to manufacture thermoplastic Kevlar and glass fiber‐reinforced composites employing wet layup process and cured at an elevated temperature under pressure. These SPEEK composites passed the flame retardancy UL94 test with a V0 rating. The average water contact angle of the glass fiber‐ and Kevlar‐SPEEK composites is 93.67° and 102.24°, respectively. The average tensile strength values of these composites were found 222.22 and 284.35 MPa, correspondingly. The smoke density and toxicity tests of the glass fiber‐SPEEK composite confirmed lower smoke generation with the modifications. These SPEEK‐fiber composites can be considered for various industrial applications, including aviation, energy, drone, defense, and automotive.
Monitoring natural organic matter in drinking water treatment with photoelectrochemical oxygen demand
Authors: DeMont Isobel , Anderson Lindsay E. , Bennett Jessica L. , Sfynia Chrissa , Bjorndahl Paul , Jarvis Peter , Stoddart Amina K. , Gagnon Graham A. 
Published: June 2024

AbstractConventional metrics such as total organic carbon (TOC) and ultraviolet absorbance at 254 nm (UV254) may oversee aspects of natural organic matter (NOM) reactivity in drinking water treatment. The novel photoelectrochemical oxygen demand (peCOD) analyzer indirectly measures the oxygen consumed during NOM oxidation with photo‐ and electrochemical methods, quantifying NOM reactivity. peCOD was valuable for tracking NOM degradation in nine drinking water treatment facilities, particularly in processes where conventional metrics failed to capture changes in NOM from partial oxidation (e.g., biofiltration and oxidation). However, peCOD exhibited moderate correlations with TOC (R2 = 0.67) and UV254 (R2 = 0.48), indicating the need for its concurrent use with conventional methods. While peCOD was not a significant predictor of disinfection by‐product formation potential (R2 < 0.20), its inclusion alongside standard NOM metrics improved the performance of multivariable regression models. Thus, peCOD provided a rapid, standardized, operator‐friendly, environmentally conscious, concentration‐based approach for evaluating NOM characteristics in drinking water samples.
Smart Electrolytes for Lithium Batteries with Reversible Thermal Protection at High Temperatures
Authors: Yu Qian , Sun Wei , Wang Shuai , Qiu Qian , Zhang Wenjun , Tian Haoran , Xia Lan , Müller‐Buschbaum Peter 
Published: June 2024

AbstractBattery safety is a multifaceted concern, with thermal runaway standing out as a primary issue. In this work, we introduce a novel temperature‐responsive, self‐protection electrolyte governed by the phase separation dynamics of poly (butyl methacrylate) (PBMA) in lithium salt/tetraglyme (G4) blends. This innovation effectively mitigates the risks associated with thermal runaway in lithium batteries. Our electrolyte exhibits a temperature‐responsive‐recovery characteristic, imparting intelligent capabilities to lithium batteries. At temperatures of >105 °C, the electrolyte transitions from a homogeneous phase to a segregated state, comprising a PBMA‐rich phase with low conductivity and a high conductivity phase containing dissolved lithium salt in G4. The deposition of the PBMA‐rich phase on the electrode surface obstructs the ion transport, thereby averting a thermal runaway. Subsequently, upon returning to room temperature of 25 °C, the electrolyte reverts to its homogeneous, highly conductive state, with battery capacity resuming at approximately 94 %. Thus, our electrolyte offers a robust, reversible, smart self‐protection for batteries. Additionally, it demonstrates exceptional cycling performance at room temperature. Our findings open new avenues for thermo‐reversible and self‐protective electrolytes, advancing the safe and widespread adoption of lithium‐ion batteries.
ER stress‐induced transcriptional response reveals tolerance genes in yeast
Authors: Xie Jingrong , Xiao Chufan , Pan Yuyang , Xue Songlyu , Huang Mingtao 
Published: June 2024

AbstractSaccharomyces cerevisiae is important for protein secretion studies, yet the complexities of protein synthesis and secretion under endoplasmic reticulum (ER) stress conditions remain not fully understood. ER stress, triggered by alterations in the ER protein folding environment, poses substantial challenges to cells, especially during heterologous protein production. In this study, we used RNA‐seq to analyze the transcriptional responses of yeast strains to ER stress induced by reagents such as tunicamycin (Tm) or dithiothreitol (DTT). Our gene expression analysis revealed several crucial genes, such as HMO1 and BIO5, that are involved in ER‐stress tolerance. Through metabolic engineering, the best engineered strain R23 with HMO1 overexpression and BIO5 deletion, showed enhanced ER stress tolerance and improved protein folding efficiency, leading to a 2.14‐fold increase in α‐amylase production under Tm treatment and a 2.04‐fold increase in cell density under DTT treatment. Our findings contribute to the understanding of cellular responses to ER stress and provide a basis for further investigations into the mechanisms of ER stress at the cellular level.
Modulation of habenular and nucleus accumbens functional connectivity by ketamine in major depression
Authors: Taraku Brandon , Loureiro Joana R. , Sahib Ashish K. , Zavaliangos‐Petropulu Artemis , Al‐Sharif Noor , Leaver Amber M. , Wade Benjamin , Joshi Shantanu , Woods Roger P. , Espinoza Randall , Narr Katherine L. 
Published: June 2024

AbstractIntroductionMajor depressive disorder (MDD) is associated with dysfunctional reward processing, which involves functional circuitry of the habenula (Hb) and nucleus accumbens (NAc). Since ketamine elicits rapid antidepressant and antianhedonic effects in MDD, this study sought to investigate how serial ketamine infusion (SKI) treatment modulates static and dynamic functional connectivity (FC) in Hb and NAc functional networks.MethodsMDD participants (n = 58, mean age = 40.7 years, female = 28) received four ketamine infusions (0.5 mg/kg) 2−3 times weekly. Resting‐state functional magnetic resonance imaging (fMRI) scans and clinical assessments were collected at baseline and 24 h post‐SKI. Static FC (sFC) and dynamic FC variability (dFCv) were calculated from left and right Hb and NAc seeds to all other brain regions. Changes in FC pre‐to‐post SKI, and correlations with changes with mood and anhedonia were examined. Comparisons of FC between patients and healthy controls (HC) at baseline (n = 55, mean age = 32.6, female = 31), and between HC assessed twice (n = 16) were conducted as follow‐up analyses.ResultsFollowing SKI, significant increases in left Hb‐bilateral visual cortex FC, decreases in left Hb‐left inferior parietal cortex FC, and decreases in left NAc‐right cerebellum FC occurred. Decreased dFCv between left Hb and right precuneus and visual cortex, and decreased dFCv between right NAc and right visual cortex both significantly correlated with improvements in mood ratings. Decreased FC between left Hb and bilateral visual/parietal cortices as well as increased FC between left NAc and right visual/parietal cortices both significantly correlated with improvements in anhedonia. No differences were observed between HC at baseline or over time.ConclusionSubanesthetic ketamine modulates functional pathways linking the Hb and NAc with visual, parietal, and cerebellar regions in MDD. Overlapping effects between Hb and NAc functional systems were associated with ketamine's therapeutic response.
Selective Activity Against Amastigote Forms of Trypanosoma cruzi and Leishmania infantum of Diastereomeric Dicentrine N‐oxides
Authors: Tristão Daniela C. , Barbosa Henrique , de Castro Levatti Erica V. , Andrade Beatriz A. , Romanelli Maiara M. , Antar Guilherme M. , Tempone Andre G. , Lago João Henrique G. 
Published: June 2024

AbstractAs part of our continuous research for the discovery of bioactive compounds against Trypanosoma cruzi and Leishmania infantum, the alkaloid (6aS)‐dicentrine (1) was oxidized to afford (6aS,6S)‐ (2) and (6aS,6R)‐ (3) dicentrine‐N‐oxides. Evaluation of the cytotoxicity against NCTC cells indicated that 2 and 3 are non‐toxic (CC50>200 μM) whereas 1 demonstrated CC50 of 52.0 μM. Concerning T. cruzi activity against amastigotes, derivatives 2 and 3 exhibited EC50 values of 9.9 μM (SI>20.2) and 27.5 μM (SI>7.3), respectively, but 1 is inactive (EC50>100 μM). Otherwise, when tested against L. infantum amastigotes, 1 and 3 exhibited EC50 values of 10.3 μM (SI=5.0) and 12.7 μM (SI>15.7), respectively, being 2 inactive (EC50>100 μM). Comparing the effects of positive controls benznidazol (EC50=6.5 μM and SI>30.7) and miltefosine (EC50=10.2 μM and SI=15.2), it was observed a selective antiparasitic activity to diastereomers 2 and 3 against T. cruzi and L. infantum. Considering stereochemical aspects, it was suggested that the configuration of the new stereocenter formed after oxidation of 1 played an important role in the bioactivity against amastigotes of both tested parasites.
Linkage Conversion in Covalent Organic Frameworks: An Efficient Strategy to Promote Photocatalytic Organic Transformations
Authors: Pang Huaji , Huang Dekang , Xiang Yonggang 
Published: June 2024

AbstractCovalent organic frameworks (COFs) are emerging as promising heterogeneous photocatalysts for organic transformations, owing to their fascinating optical properties, excellent recyclability, and customizable chemical structures. To maximize the photocatalytic activity of COFs, various strategies have been explored, including metal complexation, construction of donor‐acceptor structures, modification of functional groups, hybridization with inorganic semiconductors, and linkage conversion. Among these, linkage conversion has proved to be particularly effective, driving the production of numerous value‐added organic chemicals. In this concept article, we present a comprehensive overview of the latest advancements in linkage conversion and highlight the most enlightening examples that have adopted such a strategy to boost the photocatalytic capabilities of COFs for organic transformations. It is anticipated that this concept will assist researchers in designing novel COFs with multifunctional linkages, paving the way towards their broader application in organic synthesis.
Facile Construction of Quaternary Carbon Centers via Dinuclear Titanium(III)‐Catalyzed Reductive Coupling of Tertiary Chlorides and Activated Olefins
Authors: Chen Wanjiao , Sun Huaxi , Jiang Jie , Zhang Yong‐Qiang 
Published: June 2024

AbstractThe establishment of all‐carbon quaternary carbon centers represents a pivotal aspect in the synthesis of numerous natural products and pharmaceutical compounds, underscoring its paramount significance in synthetic organic chemistry. Herein, we present a novel synthetic strategy for the generation of quaternary carbon centers through the reductive coupling of tertiary halides, catalyzed by dinuclear (salen)titanium catalysts. This catalytic framework demonstrates notable reactivity towards tertiary chlorides while maintaining inertness towards secondary and primary chlorides, thereby facilitating exceptional chemoselectivity for C−C bond formation. The reaction proceeds with remarkable efficiency across a diverse range of substrates under mild reaction conditions.
Electrochemical Behaviour of (n‐Bu4N)4[AsVMo11O40] and (n‐Bu4N)4[AsV2Mo10O40] Doped PEDOT Film and Its Quartz Crystal Microbalance Studies
Authors: Sakthinathan Indherjith , Ueda Tadaharu , McCormac Timothy 
Published: June 2024

AbstractKeggin‐type polyoxometalates (POMs), (n‐Bu4N)4[AsVMo11O40] (AsVMo11) and (n‐Bu4N)4H[AsV2Mo10O40] (AsV2Mo10), have been immobilised with the conducting polymer poly (3,4‐ethylenedioxythiophene) (PEDOT) on the surface of the glassy carbon electrode via chronocoulometry technique. The voltammetric behaviour of these modified electrodes was investigated with cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The resulting films showed the surface adsorbed behaviour and dependence on the pH of the electrolyte solution. By using AC impedance, it was found that the resulting POM‐doped PEDOT films were highly conductive. The redox switching stability of the polymer films was investigated, and it was found that the AsVMo11/PEDOT hybrid film is significantly more stable for continuous potential sweep than the AsV2Mo10/PEDOT hybrid film. Additionally, the EQCM measurements confirm that during the redox potential cycling, the anions in the supporting electrolyte replace the POMs anion doped onto the film.
Domain adaptation via gamma, Weibull, and lognormal distributions for fault detection in chemical and energy processes
Authors: Yang Lingkai , Cheng Jian , Luo Yi , Zhou Tianbai , Zhang Xiaoyu , Shi Linsong , Xu Yuan 
Published: June 2024

AbstractThe burgeoning development of supervised machine learning (ML) has led to its widespread applications in chemical and energy processes, such as fault detection. However, in some scenarios, collecting labelled data can be costly, hazardous, or impossible. Moreover, data of the same process can follow varying distributions due to changes in, for example, devices and environment, causing ML models to be ineffective. These challenges pose a domain adaptation task, necessitating the refinement of existing ML models to tackle issues from related applications. This study proposes a domain adaptation approach to address label scarcity and data distribution variation. The method has three stages: data distribution modelling (knowledge discovery), adaptation of target domain samples to source domains (knowledge transformation), and classifier ensemble for fault detection (knowledge fusion). Gamma, Weibull, and lognormal distributions are applied for data modelling and domain adaptation. The effectiveness of the method is validated on synthetic datasets and then applied to identify anomalies in coal mine pressure data and detect faults in the Tennessee Eastman (TE) process.
Emergent Physics in Metal−Organic Frameworks
Authors: Wang Shaoze , Wang Yingchao , Sun Haozhou , Sun Lei 
Published: June 2024

AbstractMany‐body interactions in condensed matter could lead to emergent phenomena spanning superconductivity, ferromagnetism, exciton condensation, etc. The emergence of these phenomena often requires highly ordered spatial arrangements of the interacting species to enforce specific space symmetries and interacting strengths. Metal−organic frameworks (MOFs), crystalline materials formed by self‐assembly of metal ions and organic ligands, allow for precise design of their crystal structures and sophisticated tuning of Coulombic interaction or magnetic coupling among lattice sites. Such atomic‐level designability combined with high crystallinity and versatile types of lattices (e.g., kagome and honeycomb lattices) render MOFs as a great platform to investigate emergent physics. In this Emerging Topic, we summarize recent studies evidencing emergent phenomena in MOFs including strong correlations, superconductivity, charge density wave, long‐range magnetic order, and quantum spin liquid. We highlight the great potential of MOFs as quantum materials and discuss challenges including growth of high‐quality single crystals and in‐depth physical characterizations to reveal insights into the nature of physical properties of MOFs.
Key Scientists
Comparison – An Approach for chemistry beginners to improve a basic cognitive competence
Authors: Heimann Rebekka , Rienäcker Ina 
Published: June 2024

AbstractIn diesem Beitrag werden Arbeitsblätter zu zehn thematischen Feldern des Chemieanfangsunterrichts vorgestellt, die dazu dienen sollen, die Grundfertigkeit des Vergleichens und die wichtige naturwissenschaftliche Fähigkeit der Faktorenkontrolle zu schulen. Sie wurden in Anlehnung an ein kognitives Lerntraining von Feuerstein entwickelt.
Suppression of Lattice Doubling in Quasi‐Skutterudite La3Rh4Sn13: A Comparison of Temperature and Hydrostatic Pressure Routes
Authors: Sundaramoorthy Muthukumaran , Lingannan Govindaraj , Kumar Mondal Pradip , Lue C. S. , Kuo C. N. , Arumugam Sonachalam , Joseph Boby 
Published: June 2024

AbstractWe present structural properties at different temperatures and high‐pressure (HP) of La3Rh4Sn13 which is one of the interesting systems in the Remika phase RE3Rh4Sn13 (RE=Sr, Ca, La, Pr, Ce) quasi‐skutterudite series using synchrotron diffraction. Data at ambient conditions revealed the presence of several weak reflections, which could be accounted only with a superlattice I* structure (I4132) with lattice parameter a~19.457 Å. However, above 350 K, a complete suppression of the weak superlattice reflections of the I* structure is observed. Data at higher temperatures is found to be well described by the I structure (Pm‐3n) having half the lattice parameter compared to the I* structure. HP‐XRPD at ambient temperature showed that pressures greater than 7.5 GPa result in similar suppression of the weak I* superlattice reflections. Data at higher pressures is found to be well described by the I structure (Pm‐3n), similar to the high‐temperature phase. HP Raman measurements demonstrated changes that seem to be consistent with a locally more ordered structure as in the case of the I*→I transition. Our findings on La3Rh4Sn13 open up new avenues to study unexplored HP phenomena, especially the superconductivity in these Remika phase quasi‐skutterudites.
Dihedral Angles and Photoluminescence Quantum Yields: An NMR Analysis
Authors: Goll Felix D. , Dießner Nicolas , Kuehne Alexander J. C. , Ziener Ulrich 
Published: June 2024

AbstractThe synthesis of two different series of donor–acceptor (D−A) molecules is reported, consisting of a series of four structurally related donors and two different acceptors. The subtle differences in the electron density of these D−A−D and D−A compounds are clearly reflected in the different chemical shifts of certain donor protons in the 1H NMR spectra. These shifts show a cosine squared correlation of the dihedral angle between the donor units and the neighbouring phenyl unit of the acceptor. This correlation is also related to optical properties such as the photoluminescence quantum yield, which shows a similar trend due to the different degree of charge transfer during excitation and relaxation processes. In this way, it is possible to directly correlate a molecular structural parameter with a material property on a purely experimental basis, which should be applicable to many donor‐acceptor systems.