bluuebunny/crossref_metadata_2025_split huggingface dataset:
Balancing Carrier Dynamics in Oxygen‐Vacancy‐Tuned Amorphous Ga2O3 Thin‐Film Self‐Powered Photoelectrochemical‐Type Solar‐Blind Photodetector Arrays for Underwater Imaging
Authors: Ding Ke , Zhang Hong , Jiang Jili , Luo Jiangshuai , Wu Rouling , Ye Lijuan , Tang Yan , Pang Di , Li Honglin , Li Wanjun 
Published: September 2024

AbstractUnderwater imaging technology plays a pivotal role in marine exploration and reconnaissance, necessitating photodetectors (PDs) with high responsivity, fast response speed, and low preparation costs. This study presents the synergistic optimization of responsivity and response speed in self‐powered photoelectrochemical (PEC)‐type photodetector arrays based on oxygen‐vacancy‐tuned amorphous gallium oxide (a‐Ga2O3) thin films, specifically designed for solar‐blind underwater detection. Utilizing a low‐cost one‐step sputtering process with controlled oxygen flow, a‐Ga2O3 thin films with varying oxygen vacancy (VO) concentrations are fabricated. By balancing the trade‐offs among electrocatalytic reactions, charge transfer, carrier recombination, and trapping, both the responsivity and response speed of a‐Ga2O3‐based self‐powered PEC‐PDs are simultaneously improved. Consequently, the optimized PEC‐PDs demonstrated exceptional performance, achieving a responsivity of 33.75 mA W−1 and response times of 12.8 ms (rise) and 31.3 ms (decay), outperforming the vast majority of similar devices. Furthermore, a pronounced positive correlation between anomalous transient photocurrent spikes and the concentration of VO defects is observed, offering compelling evidence for VO‐mediated indirect recombination. Finally, the proof‐of‐concept solar‐blind underwater imaging system, utilizing an array of self‐powered PEC‐PDs, demonstrated clear imaging capabilities in seawater. This work provides valuable insight into the potential for developing cost‐effective, high‐performance a‐Ga2O3 thin‐film‐based PEC‐PDs for advanced underwater imaging technology.
Optimizing Molecular Packing and Film Morphology in Organic Solar Cells via Additive‐Modulated Growth Processes
Authors: Cui Xinyue , Ji Yitong , Liu Yuqiang , Ma Xueqing , Li Hongxiang , Cheng Pei , Huang Wenchao , Bo Zhishan 
Published: September 2024

AbstractControlling the packing feature and film morphology of active layers is the precondition for achieving highly efficient organic solar cells (OSCs). The growth transition of donors and acceptors from solution to solid films plays an intrinsic role in shaping these features. In this study, two simple additives, cyanobenzene (CNB) and 1,4‐dicyanobenzene (DCNB), are presented to modulate the growth process of active layers to investigate the impact of growth behaviors on molecule packing quality, film morphology, and device performances. Both additives prolong the nucleation and growth period of active layers, resulting in improved molecular packing quality, domain purity, and crystallization. This optimization enhances charge extraction efficiency as well as reduces charge recombination losses. Consequently, devices based on D18:BTP‐eC9‐4F processed with additives obtain a 19.43% power conversion efficiency (PCE). Furthermore, a PCE of 14.35% is achieved for bladed‐coated organic solar modules on 5 cm × 5 cm substrates. These findings underscore the importance of growth processes on film quality and illustrate their fundamental relationship, which promises further advancements in OSC technology.
Mechano‐Electrochemical Behavior of Nanostructured Li‐ and Mn‐Rich Layered Oxides with Superior Capacity Retention and Voltage Decay for Sulfide‐Based All‐Solid‐State Batteries
Authors: Song Gawon , Lee Suyeon , Kim Taehun , Jung Min Soo , Kim Kanghyeon , Choi Seung Hyun , Lee Seunghyun , Park Junsung , Lee Minseon , Park Chanhwi , Kwon Mi‐Sook , Lee Kyu Tae 
Published: September 2024

AbstractLi‐ and Mn‐rich layered oxides (LMROs) are recognized as promising cathode materials for lithium‐ion batteries (LIBs) due to their high specific capacity and cost efficiency. However, LMROs encounter challenges such as manganese dissolution in electrolytes and the release of oxygen gas from irreversible oxygen redox reactions, leading to structural degradation and voltage decay that reduce energy density. Consequently, recent research has shifted toward employing LMROs in all‐solid‐state batteries (ASSBs), where Mn dissolution is negligible. Herein, nanostructured LMROs demonstrate superior electrochemical compatibility with sulfide‐based solid electrolytes in ASSBs compared to conventional LIBs. Nanostructured LMRO exhibits outstanding capacity retention (97.1% after 1300 cycles at 30 °C) with significantly suppressed voltage decay. Furthermore, the initial electrochemical activation of Li2MnO3 domains within LMRO is explored in terms of the mechano‐electrochemical interactions in the composite cathode. At elevated temperatures, interfacial degradation accelerates due to the chemical oxidation of Li6PS5Cl solid electrolytes, driven by oxygen released from LMRO. To address this, LMRO surfaces are modified with thioglycolic acid through esterification, suppressing interfacial degradation of Li6PS5Cl and ensuring stable capacity retention over 500 cycles at 60 °C. These findings underscore the potential of LMRO materials as promising cathode options for ASSBs, surpassing those used in LIBs.
Surface Lattice Engineering Enables Efficient Inverted Perovskite Solar Cells
Authors: Zhang Tianchi , Liu Tiantian , Wang Xingtao , Zhou Yuhan , Wen Yehui , Li Junhang , Bao Chunqiong , Wan Li , Yu Xuegong , Ning Weihua , Wang Yong , Yang Deren 
Published: September 2024

AbstractState‐of‐the‐art inverted perovskite solar cells (PSCs) have exhibited considerable promise for commercialization due to their prospective stability. However, the intricate crystallization of halide perovskite, especially for multi‐component perovskites, not only distorts the surface lattice from its ideal form but also introduces numerous unsaturated dangling bonds to form surface defects, which can easily lead to reduced stability and poor performance. Herein, a surface lattice engineering is developed by coupling surface unsaturated ions and regulating ion bonding lengths/angles to achieve efficient and stable inverted PSCs. The renovated surface lattice not only eliminates shallow/deep level defects on the surface of perovskite, but also enhances photo/thermal stability of the materials. Moreover, the surface lattice engineering contributes to uniform potential surface, and improves energy‐level alignment at the interfaces of the perovskite and C60 carrier transport layer, enhancing charge carrier extraction and transportation. Finally, the champion PSC delivers an impressive efficiency of 25.82% (certified 25.5%). Moreover, these PSCs exhibit excellent operational stability, retaining 94% initial efficiency after more than ≈1 000h maximum power point test.
Intrinsic Electron Transfer in Heteronuclear Dual‐Atom Sites Facilitates Selective Electrocatalytic Carbon Dioxide Reduction
Authors: Tang Qi , Hao Qi , Zhu Qian , Wu Junxiu , Huang Keke , Liu Kai , Lu Jun 
Published: September 2024

AbstractThe metal–metal (M1–M2) interactions in heteronuclear dual‐atom catalysts (HNDACs) significantly optimize the electronic properties of the active sites, resulting in the promotion of the reaction kinetics in electrocatalysis. However, the regulation mechanisms in these M1–M2 dual‐atom sites still remain unclear. Herein, the intrinsic electron transfer in Fe–Zn dual‐atom sites are revealed for facilitating electrocatalytic carbon dioxide reduction (ECO2R) to carbon monoxide (CO). The electronegativity difference between the Fe and Zn centers induces the specific electron transfer from Zn to Fe, which regulates the electron structures of the active Zn sites, leading to the optimized reaction pathway of CO2‐to‐CO conversion on these sites. The Fe–Zn HNDAC (FeZnNC) exhibits superior ECO2R performances than the single‐atom Fe/Zn catalysts (FeNC and ZnNC) in the typical H‐cell system, the maximum CO partial current density on FeZnNC reaches more than 3.3 and 1.8 folds of those on FeNC and ZnNC, respectively. More importantly, in a strongly acidic medium (pH = 1), FeZnNC achieves CO Faradaic efficiencies greater than 94% in the current density range of 100–400 mA cm−2. This work uncovers the intrinsic electron transfer at the heteronuclear diatomic sites, providing new insights for the rational design of high‐performance HNDACs toward industrial electrocatalysis.
Regulating Fe Intermediate Spin States via FeN4‐Cl‐Ti Structure for Enhanced Oxygen Reduction
Authors: Zhang Shuren , Han Yitong , Zhang Rui , Zhang Zhiyuan , Sun Genban 
Published: September 2024

AbstractModulating the spin states of FeN4 moieties is critical for enhancing the electrocatalytic oxygen reduction reaction (ORR). In this study, Ti4N3Clx and Ti4N3Ox MXenes are synthesized and functionalized with iron phthalocyanine (FePc) to form model catalysts with well‐defined FeN4‐Cl‐Ti and FeN4‐O‐Ti structures, respectively. The FeN4‐Cl‐Ti structure, formed within the Ti4N3Clx/FePc composite, enables precise modulation of FeN4 spin states from low to intermediate spin, significantly enhancing ORR performance. In contrast, the FeN4‐O‐Ti structure in Ti4N3Ox/FePc shows less effective spin state modulation, leading to comparatively lower ORR activity. Compared to FePc and Ti4N3Ox/FePc, Ti4N3Clx/FePc demonstrates superior electrochemical performance, with an ORR half‐wave potential of +0.91 V versus RHE and doubled power densities in Zn–air batteries (214.5 mW cm−2). Theoretical studies confirm that the intermediate spin states induced by the weak‐field ligand‐modified FeN4‐Cl‐Ti structure in Ti4N3Clx/FePc facilitate electron filling in the antibonding orbital composed of Fe 3dz2 and O2 π* orbitals, greatly enhancing O₂ activation and ORR activity. These findings underscore the superior catalytic properties of FeN4‐Cl‐Ti compared to FeN4‐O‐Ti, advancing the understanding of spin state‐related catalytic mechanisms and guiding the design of high‐performance ORR catalysts.
Regioselektiver, photoredox‐katalysierter Wasserstoffisotopenaustausch an benzylischen Positionen
Authors: Stinglhamer Martin , Kuhlmann Jan Hendrik , Martinelli Elisa , Perulli Stefania , Sandvoss Martin , Mück‐Lichtenfeld Christian , Derdau Volker , García Mancheño Olga 
Published: September 2024

AbstractEs wird ein hochgradig regioselektiver, von sichtbarem Licht photoredox‐katalysierter Wasserstoff‐isotopenaustausch (WIA) an benzylischen Positionen von einfachen und komplexen Molekülen beschrieben. Der Prozess folgt einem dual katalytischen Ansatz, basierend auf der Kombination eines Acridinium‐Photokatalysators mit einem Thiol basierten Wasserstoffatomtransfer Katalysator (HAT). Die Verwendung von D2O als Isotopenquelle gewährleistet hierbei eine einfache Handhabung und Kosteneffizienz. Es konnte eine hohe Reaktivität für elektronenreiche benzylische Positionen erreicht werden. Die gezielte Bildung von Radikalen ermöglicht einen selektiven WIA an intramolekular konkurrierenden Benzyl‐ und alpha zu Heteroatom‐positionen mit moderatem bis ausgezeichnetem Deuteriumeinbau. Der Nutzen dieser Reaktion wurde durch WIA an verschiedenen Naturstoff‐ und Arzneimittelderivaten demonstriert. Experimentelle Studien und Dichtefunktionaltheorieberechnungen (DFT) legen einen Ein‐Elektronen‐Übertragungsmechanismus (SET) nahe, gefolgt von einer Deprotonierung zur Bildung des benzylischen Radikals. Hierbei konnte die Bedeutung von halogenierten Lösungsmitteln oder Additiven demonstriert werden. Die schwache Interaktion der Halogenspezies mit dem Substrat führt zur Bildung eines Komplexes. Dies resultiert in einer Senkung des Oxidationspotenzials und einer Stabilisierung der Radikal‐Kation‐Spezies durch Spin‐Delokalisierung.
Pyrrolic‐Nitrogen Chemistry in 1‐(2‐hydroxyethyl)imidazole Electrolyte Additives toward a 50,000‐Cycle‐Life Aqueous Zinc‐Iodine Battery
Authors: Chen Jiajun , Ou Genyuan , Liu Peifen , Fan Wenju , Li Bing , Hu Zuyang , Wen Zhipeng , Zhang Yufei , Tang Yongchao , Liu Xiaoqing , Ye Minghui , Li Cheng Chao 
Published: September 2024

AbstractRechargeable aqueous zinc iodine (Zn‐I2) batteries offer benefits such as low cost and high safety. Nevertheless, their commercial application is hindered by hydrogen evolution reaction (HER) and polyiodide shuttle, which result in a short lifespan. In this study, 1‐(2‐hydroxyethyl)imidazole (HEI) organic molecules featuring pyrrole‐N groups are introduced as dually‐functional electrolyte additives to simultaneously stabilize Zn anode and confine polyiodide through ion‐dipole interactions. The pyrrole‐N groups in HEI can preserve the interfacial pH equilibrium at Zn anode by reversibly capturing H+ ions and dynamically neutralizing OH− ions, thereby suppressing the HER. Notably, the H2 evolution rate at the Zn anode is reduced to a mere 2.20 μmol h−1 cm−2. Furthermore, the pyrrole‐N moieties in HEI effectively curtail the polyiodide shuttle at I2 cathode, which show adsorption energies of −0.174 eV for I2, −0.521 eV for I3−, and −0.768 eV for I−, as indicated by density functional theory calculations. Electrochemical testing demonstrates that the Zn//Zn symmetric cell maintains stable cycling for up to 4,200 hours at 1 mA cm−2. Most strikingly, at a high I2 mass loading of 9.7 mg cm−2, the Zn‐I2 battery achieves an extraordinary cycle life of 50,000 cycles.
Increasing the Donor Strength of Alkenylphosphines by Twisting the C=C Double Bond
Authors: Yu Cheng‐Han , Hsiao Yu‐Wen , Löffler Julian , Kaiser Nicolas , Huang Bo‐Hong , Lee Chao‐Hsien , Hung Chen‐Hsun , Shen Jiun‐Shian , Yap Glenn P. A. , Gessner Viktoria H. , Ong Tiow‐Gan 
Published: September 2024

AbstractElectron‐rich phosphines play a crucial role in transition metal‐based homogeneous catalysis. While alkyl groups have traditionally been employed to increase the phosphine donor strength, recent studies have shown that zwitterionic functional groups such as phosphorus ylides can result in a further enhancement. Herein we report the concept of twisting a C=C double bond to introduce a zwitterionic substituent by the synthesis and application of N‐heterocyclic olefin phosphines with a sulfonyl substituent (sNHOP). This sulfonyl group enables the twisting of the olefin moiety due to steric and electronic stabilization of the carbanionic center. The resulting zwitterionic structure leads to a significant increase of the donor strength of the sNHOP ligands compared to conventional NHOP systems with a planar N‐heterocyclic olefin moiety. The potential of this new ligand platform for catalysis is demonstrated by its application in the gold‐catalyzed hydroamination and cyclo‐isomerization of alkynes. Here, the ligands outperform the original NHOP ligands suggesting favorable properties for future catalysis applications.
Synthesis, Structural Determination, DFT Calculation and Biological Evaluation Supported by Molecular Docking Approach of Some New Complexes Incorporating (E)‐N'‐(3,5‐di‐Tert‐Butyl‐2‐Hydroxybenzylidene) Isonicotino Hydrazide Ligand
Authors: Al‐Farraj Eida S. , Qasem Hamza A. , Aouad Mohamed Reda , Al‐Abdulkarim Hessah A. , Alsaedi Wael H. , Khushaim Muna S. , Feizi‐Dehnayebi Mehran , Al‐Ghamdi Khalaf , Abu‐Dief Ahmed M. 
Published: September 2024

ABSTRACTThe synthesis and structural analysis of complexes derived from (E)‐N′‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene) isonicotino hydrazide (ITB ligand) were examined using multiple analytical techniques. These techniques included TGA, decomposition point determination, elemental analysis (CHN), spectroscopic (IR, NMR, mass spectrometry) analysis, magnetic susceptibility, conductivity, as well UV–Vis spectrum analysis, along with theoretical studies. Molar conductance values indicated that the Cd (II), Co (II), Cu (II), Ni (II), and Zn (II) complexes are non‐electrolytes in fresh DMSO solutions, with conductance values ranging from 8.5 to 14.35 Ω−1 cm2 mol−1. IR spectra suggested which the ligand coordinates through the metal ions in a tridentate fashion, utilizing the (N & O) donor sites from the (CN & CO & CO) groups in the hydroxybenzylidene moiety. Analytical data from solution complexation, job's method suggested a 1:1 (metal:ligand) molar ratio. The stability order of the complexes was determined as ITBCo > ITBCu > ITBNi > ITBZn > ITBCd, consistent with the stability constant (Kf) values. The pH profile indicated that the studied complexes exhibit stability upon a wide pH scale, typically between (pH = 4:10). Magnetic and electronic spectral analyses helped deduce the ligand coordination abilities and the geometric structures of the complexes. In vitro (antimicrobial & anticancer) performances of the studied complexes were tested versus various (microbial strains & cancer cell lines), revealing higher activity in the chelates assessed to the free (ITB) ligand. The antioxidant potential was also assessed using the DPPH assay. Finally, molecular docking was performed toward estimate the binding efficiency between various protein receptors and the compounds, with results aligning with the biological investigations.
High Surface Area Nanoporous Carbon‐Ceria Composites for CO2 Capture and Enzyme‐Mimicking Action
Authors: Singh Gurwinder , Maria Ruban Ajanya , Kaur Harleen , Patel Vaishwik , Ismaili Arsh A. , Bahadur Rohan , Vinu Ajayan 
Published: September 2024

AbstractNanoporous carbon‐based composites with metal oxides have great potential for various applications including adsorption and sensing owing to their multiple properties. However, the fabrication of these nanocomposites without affecting these multiple properties is challenging. Herein, a series of nanoporous carbon‐based nanocomposites with cerium nanoparticles are synthesized through a combination of high‐temperature carbonization and ex‐situ modification with cerium precursor. The prepared nanocomposites have appreciable surface areas, pore volumes, tunable pore sizes, and a controlled amount of surface nanoceria, all of which can be precisely controlled by varying the amount of KOH and cerium nitrate hexahydrate used for nanoceria generation. The porous carbon PC‐3 was used for modification using nanoceria and the modified materials showed higher performance for the intended applications. The CO2 adsorption per unit surface of PC‐3 (2.4 μmol m−2) increased to 2.9 μmol m−2 in Ce‐PC‐3–0.5. Furthermore, the composite materials displayed higher heat of adsorption (Qst) than bare materials, indicating stronger interactions with CO2. Interestingly, the least amount of nanoceria (CePC‐3–0.25) was effective in enhancing the superoxide dismutase (SOD) and catalase activity.
Effect of acute kidney injury and overall survival in patients with postoperative head and neck cancer who received chemoradiotherapy with cisplatin: A supplementary analysis of the phase II/III trial of JCOG1008
Authors: Imamura Yoshinori , Kiyota Naomi , Tahara Makoto , Kodaira Takeshi , Hayashi Ryuichi , Nishino Hiroshi , Asada Yukinori , Mitani Hiroki , Iwae Shigemichi , Nishio Naoki , Onozawa Yusuke , Hanai Nobuhiro , Ohkoshi Akira , Hara Hiroki , Monden Nobuya , Nagaoka Masato , Minami Shujiro , Kitabayashi Ryo , Sasaki Keita , Homma Akihiro ,   the Head and Neck Cancer Study Group of the Japan Clinical Oncology Group (JCOG‐HNCSG)
Published: September 2024

AbstractBackgroundIn a randomized phase II/III trial (JCOG1008), weekly cisplatin (40 mg/m2) was non‐inferior to 3‐weekly cisplatin (100 mg/m2) for postoperative high‐risk head and neck cancer. We investigated how acute kidney injury (AKI), a major dose‐limiting toxicity effect of cisplatin, affects overall survival (OS).MethodsWe analyzed 251 patients from JCOG1008 receiving chemoradiotherapy. AKI was defined based on AKI Network criteria (serum creatinine increase of ≥0.3 mg/dL or ≥1.5‐fold [≥ stage I]) within 30 days after completing chemoradiotherapy. OS in the two arms was compared according to AKI development using the log‐rank test.ResultsThe total incidence of AKI was lower in the weekly arm than in the 3‐weekly arm (38/122 [31.1%] vs. 56/129 [43.4%]). Additionally, stage II/III AKI occurred less frequently in the weekly arm than in the 3‐weekly arm (8/122 [6.6%] vs. 19/129 [14.7%]). Cisplatin doses were similar in the weekly arm for patients with and without AKI (median, 238.6 mg/m2 vs. 239.2 mg/m2; p = 0.94), but lower in the 3‐weekly arm for those who developed AKI (median, 276.3 mg/m2 vs. 297.4 mg/m2; p = 0.007). In the weekly arm, there was no difference in OS between patients with and without AKI (hazard ratio [HR], 1.06; 95% confidence interval [CI], 0.53 to 2.10). However, in the 3‐weekly arm, patients with AKI had poorer OS than those without AKI (HR, 1.83; 95% CI, 1.04 to 3.21).ConclusionsIn this supplementary analysis of JCOG1008 data, AKI impacted the OS of patients with head and neck cancer undergoing postoperative chemoradiotherapy in the 3‐weekly arm but not in the weekly arm. Our results further endorse the utilization of weekly cisplatin at 40 mg/m2 in this setting.
Efficacy and Effectiveness Outcomes of Treatments for Double‐Exposed Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma Patients: A Systematic Literature Review
Authors: Zuber Mohammed , Akkala Sreelatha , Li Niying , Veettil Sajesh K. , Tan Chia Jie , Villa Zapata Lorenzo 
Published: September 2024

ABSTRACTBackgroundBruton's tyrosine kinase inhibitors (BTKi) and the B‐cell lymphoma 2 (BCL2) inhibitor venetoclax have significantly improved outcomes and achieved durable remission in patients with chronic lymphocytic leukemia (CLL). BTKi/venetoclax‐treated patients with exposure to both novel agents (regardless of the reason for discontinuation) are classified as “double‐exposed,” and often have poor prognoses. This study aims to assess the efficacy and effectiveness of treatments in double‐exposed CLL patients.MethodsPubMed, Embase, and Web of Science databases were searched until December 2023.ResultsWe retrieved 3948 articles for screening and included 13 publications covering nine distinct studies. Three clinical trials reported a median PFS of 16.8 months with pirtobrutinib, 13 months with lisocabtagene maraleucel, and 10.1 months with nemtabrutnib. ORR ranged from 58% with nemtabrutinib and 80% with lisocabtagene maraleucel. In observational studies, PFS ranged from 3 months with chemoimmunotherapy to 12 months with BTKi, and ORR ranged from 31.8% with chemoimmunotherapy to 85.7% with chimeric antigen receptors (CAR) T‐cell therapy.ConclusionThis study highlights the limited clinical data on efficacy outcomes for double‐exposed CLL/SLL patients. Pirtobrutinib, lisocabtagene maraleucel, and a combination of ibrutinib and venetoclax have shown promising effects. However, the scarcity of treatment options and efficacy data for patients who have failed BTKi and venetoclax underscores a significant unmet medical need.
Phytochemical Analysis and Assessment of Antioxidant and Enzyme Inhibitory Activity of Alchemilla pseudocartalinica Juz.
Authors: Uzunkaya Çağla , Gökkaya İçim , Akkaya Didem , Šoral Michal , Seyhan Gökçe , Barut Burak , Abdullah Yilmaz Mustafa , Renda Gülin 
Published: September 2024

AbstractThis study aimed to evaluate and compare the antioxidant capacity and enzyme inhibitory activity of extracts, sub‐extracts, and fractions prepared from the aerial parts and roots of A. pseudocartalinica. The phytochemical content of the active extracts was also analyzed. According to the results, ellagic acid (38.42 mg/g) was the major compound in the aerial part methanol extract and catechin (185.30 mg/g) in the root methanol extract. The DPPH inhibition activity of all fractions was monitored, with the most active one (Fr B) reaching an IC50 value of (4.92±0.59 μg/mL). All the fractions prepared from the aerial parts’ water sub‐extract showed higher a‐glucosidase inhibitory activity than the positive control acarbose. In the tyrosinase assay, Fr B (58.81±7.50 μg/mL) exhibited the highest inhibitory actions among all fractions. The structure of the major substances of the most active fraction were elucidated as quercetin 7‐O‐β‐glucopyranosyl‐3‐O‐β‐glucuronopyranoside‐ (1), and α‐[(2‐formyl‐5‐hydroxymethyl)pyrrol‐1‐yl]aspartic acid (2).