bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Real‐Time Process Analytics for Multistep Synthesis in Continuous Flow**
Authors: Sagmeister Peter , Lebl René , Castillo Ismael , Rehrl Jakob , Kruisz Julia , Sipek Martin , Horn Martin , Sacher Stephan , Cantillo David , Williams Jason D. , Kappe C. Oliver 
Published: January 2021

AbstractIn multistep continuous flow chemistry, studying complex reaction mixtures in real time is a significant challenge, but provides an opportunity to enhance reaction understanding and control. We report the integration of four complementary process analytical technology tools (NMR, UV/Vis, IR and UHPLC) in the multistep synthesis of an active pharmaceutical ingredient, mesalazine. This synthetic route exploits flow processing for nitration, high temperature hydrolysis and hydrogenation reactions, as well as three inline separations. Advanced data analysis models were developed (indirect hard modeling, deep learning and partial least squares regression), to quantify the desired products, intermediates and impurities in real time, at multiple points along the synthetic pathway. The capabilities of the system have been demonstrated by operating both steady state and dynamic experiments and represents a significant step forward in data‐driven continuous flow synthesis.
Rigid Polyimides with Thermally Activated Delayed Fluorescence for Polymer Light‐Emitting Diodes with High External Quantum Efficiency up to 21 %
Authors: Long Yubo , Chen Xiaojie , Wu Huiyan , Zhou Zhuxin , Sriram Babu Seenivasagaperumal , Wu Minming , Zhao Juan , Aldred Matthew P. , Liu Siwei , Chen Xudong , Chi Zhenguo , Xu Jiarui , Zhang Yi 
Published: January 2021

AbstractA series of rigid nonconjugated polyimide (PI)‐based thermally activated delayed fluorescence (TADF) polymers were reported for the first time, based on a “TADF‐Linker‐Host” strategy. Among of which, the TADF unit contains a typical TADF luminous core structure, the “Host” unit exhibits effective conjugation length that endows polyimide with high triplet energy, and the “Linker” unit has an aliphatic ring structure to improve solubility and inhibits intramolecular charge transfer effect. All the TADF polymers exhibit high thermal stability (Tg>308.7 °C) and refractive index (1.76–1.79). Remarkably, highly‐efficient polymer light‐emitting diodes (PLEDs) based on the polymers are successfully realized, leading to a maximal external quantum efficiency of 21.0 % along with low efficiency roll‐off. Such outstanding efficiency is amongst the state‐of‐the‐art performance of nonconjugated PLEDs, confirming the effectiveness of structural design strategy, providing helpful and valuable guidance on the development of highly‐efficient fluorescent polymer materials and PLEDs.
Exclusive Strain Effect Boosts Overall Water Splitting in PdCu/Ir Core/Shell Nanocrystals
Authors: Li Menggang , Zhao Zhonglong , Xia Zhonghong , Luo Mingchuan , Zhang Qinghua , Qin Yingnan , Tao Lu , Yin Kun , Chao Yuguang , Gu Lin , Yang Weiwei , Yu Yongsheng , Lu Gang , Guo Shaojun 
Published: January 2021

AbstractCore/shell nanocatalysts are a class of promising materials, which achieve the enhanced catalytic activities through the synergy between ligand effect and strain effect. However, it has been challenging to disentangle the contributions from the two effects, which hinders the rational design of superior core/shell nanocatalysts. Herein, we report precise synthesis of PdCu/Ir core/shell nanocrystals, which can significantly boost oxygen evolution reaction (OER) via the exclusive strain effect. The heteroepitaxial coating of four Ir atomic layers onto PdCu nanoparticle gives a relatively thick Ir shell eliminating the ligand effect, but creates a compressive strain of ca. 3.60%. The strained PdCu/Ir catalysts can deliver a low OER overpotential and a high mass activity. Density functional theory (DFT) calculations reveal that the compressive strain in Ir shell downshifts the d‐band center and weakens the binding of the intermediates, causing the enhanced OER activity. The compressive strain also boosts hydrogen evolution reaction (HER) activity and the strained nanocrystals can be served as excellent catalysts for both anode and cathode in overall water‐splitting electrocatalysis.
Assembly of Dynamic Supramolecular Polymers on a DNA Origami Platform
Authors: Schill Jurgen , Rosier Bas J. H. M. , Gumí Audenis Berta , Magdalena Estirado Eva , de Greef Tom F. A. , Brunsveld Luc 
Published: January 2021

AbstractBiological processes rely on transient interactions that govern assembly of biomolecules into higher order, multi‐component systems. A synthetic platform for the dynamic assembly of multicomponent complexes would provide novel entries to study and modulate the assembly of artificial systems into higher order topologies. Here, we establish a hybrid DNA origami‐based approach as an assembly platform that enables dynamic templating of supramolecular architectures. It entails the site‐selective recruitment of supramolecular polymers to the platform with preservation of the intrinsic dynamics and reversibility of the assembly process. The composition of the supramolecular assembly on the platform can be tuned dynamically, allowing for monomer rearrangement and inclusion of molecular cargo. This work should aid the study of supramolecular structures in their native environment in real‐time and incites new strategies for controlled multicomponent self‐assembly of synthetic building blocks.
Stanene‐Based Nanosheets for β‐Elemene Delivery and Ultrasound‐Mediated Combination Cancer Therapy
Authors: Chen Wei , Liu Chuang , Ji Xiaoyuan , Joseph John , Tang Zhongmin , Ouyang Jiang , Xiao Yufen , Kong Na , Joshi Nitin , Farokhzad Omid C. , Tao Wei , Xie Tian 
Published: January 2021

AbstractUltrasound (US)‐mediated sonodynamic therapy (SDT) has emerged as a superior modality for cancer treatment owing to the non‐invasiveness and high tissue‐penetrating depth. However, developing biocompatible nanomaterial‐based sonosensitizers with efficient SDT capability remains challenging. Here, we employed a liquid‐phase exfoliation strategy to obtain a new type of two‐dimensional (2D) stanene‐based nanosheets (SnNSs) with a band gap of 2.3 eV, which is narrower than those of the most extensively studied nano‐sonosensitizers, allowing a more efficient US‐triggered separation of electron (e−)‐hole (h+) pairs for reactive oxygen species (ROS) generation. In addition, we discovered that such SnNSs could also serve as robust near‐infrared (NIR)‐mediated photothermal therapy (PTT) agents owing to their efficient photothermal conversion, and serve as nanocarriers for anticancer drug delivery owing to the inherent 2D layered structure. This study not only presents general nanoplatforms for SDT‐enhanced combination cancer therapy, but also highlights the utility of 2D SnNSs to the field of nanomedicine.
Silver‐Catalyzed Enantioselective Sulfimidation Mediated by Hydrogen Bonding Interactions
Authors: Annapureddy Rajasekar Reddy , Burg Finn , Gramüller Johannes , Golub Tino P. , Merten Christian , Huber Stefan M. , Bach Thorsten 
Published: January 2021

AbstractAn enantioselective sulfimidation of 3‐thiosubstituted 2‐quinolones and 2‐pyridones was achieved with a stoichiometric nitrene source (PhI=NNs) and a silver‐based catalyst system. Key to the success of the reaction is the use of a chiral phenanthroline ligand with a hydrogen bonding site. The enantioselectivity does not depend on the size of the two substituents at the sulfur atom but only on the binding properties of the heterocyclic lactams. A total of 21 chiral sulfimides were obtained in high yields (44–99 %) and with significant enantiomeric excess (70–99 % ee). The sulfimidation proceeds with high site‐selectivity and can also be employed for the kinetic resolution of chiral sulfoxides. Mechanistic evidence suggests the intermediacy of a heteroleptic silver complex, in which the silver atom is bound to one molecule of the chiral ligand and one molecule of an achiral 1,10‐phenanthroline. Support for the suggested reaction course was obtained by ESI mass spectrometry, DFT calculations, and a Hammett analysis.
Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1‐Methylimidazolium Thiocyanate
Authors: Andreev Ivan A. , Ratmanova Nina K. , Augustin André U. , Ivanova Olga A. , Levina Irina I. , Khrustalev Victor N. , Werz Daniel B. , Trushkov Igor V. 
Published: January 2021

AbstractWe propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Brønsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate‐based protic ionic liquids for the ring‐opening of donor‐acceptor cyclopropanes. A wide variety of activated cyclopropanes were found to react with 1‐methylimidazolium thiocyanate under mild metal‐free conditions via unusual nitrogen attack of the ambident thiocyanate ion on the electrophilic center of the three‐membered ring affording pyrrolidine‐2‐thiones bearing donor and acceptor substituents at the C(5) and C(3) atoms, respectively, in a single time‐efficient step. The ability of 1‐methylimidazolium thiocyanate to serve as a triplex reagent was exemplarily illustrated by (4+2)‐annulation with 1‐acyl‐2‐(2‐hydroxyphenyl)cyclopropane, epoxide ring‐opening and other organic transformations.
Ligand‐Directed Approach in Polyoxometalate Synthesis: Formation of a New Divacant Lacunary Polyoxomolybdate [γ‐PMo10O36]7−
Authors: Li Chifeng , Yamaguchi Kazuya , Suzuki Kosuke 
Published: January 2021

AbstractPolyoxometalates (POMs) have received increasing attention over the last decades for extending their application and properties that originate from novel structures. For the synthesis of a variety of POM structures, multivacant lacunary POMs are key precursors, which are typically synthesized by empirically controlling the complex equilibrium in aqueous solvents. Unfortunately, despite the excellent catalytic and electrochemical properties of “polyoxomolybdates”, only one multivacant lacunary species, i.e., [A‐α‐PMo9O34]9−, has been identified and isolated because multivacant lacunary polyoxomolybdates are typically unstable. Here we report a ligand‐directed approach for the selective formation of an unprecedented lacunary polyoxomolybdate in organic solvents. By structure transformation of a pyridine‐coordinated [A‐α‐PMo9O34]9−, a new γ‐Keggin‐type divacant lacunary polyoxomolybdate [γ‐PMo10O36]7− was obtained, which can be further used as a precursor for synthesizing a POM–organic hybrid.
Die entscheidende Rolle von lokalen Ladungsfluktuationen beim Wachstum von Dendriten auf Lithium‐Elektroden
Authors: Santos Elizabeth , Schmickler Wolfgang 
Published: January 2021

AbstractObwohl sich sehr viele theoretische Arbeiten mit der Ursache der Dendritenbildung an reinen Lithium‐Elektroden befasst haben, wurde bisher ein entscheidender Faktor übersehen: Bei der Abscheidung von Lithium ist die Elektrode stark negativ geladen, und diese Ladung ist nicht gleichmäßig über die Oberfläche verteilt. Explizite Modellrechnungen zeigen, dass sich die Überschussladung auf der Spitze kleiner Unebenheiten, die durch Fluktuationen entstehen, konzentriert. Sie erzeugt dort ein starkes elektrisches Feld, welches Lithium‐Ionen anzieht, die Spitze weiter wachsen lässt und schließlich zur Bildung von Dendriten führt. Selbst eine kleine Spitze, die nur aus wenigen Atomen besteht, trägt eine Überschussladung von der Größenordnung eines Zehntels der Elektronenladung oder mehr. Zudem erniedrigt eine negative Ladung lokal die Oberflächenspannung, was die Dendritenbildung zusätzlich begünstigt. Derselbe Mechanismus kann auch die Dendritenbildung an anderen Metallen erklären, deren Abscheidungspotential tiefer liegt als der Ladungsnullpunkt.
Electrochemical Splitting of Methane in Molten Salts To Produce Hydrogen
Authors: Fan Zeyu , Xiao Wei 
Published: January 2021

AbstractIndustrial hydrogen production based on methane steam reforming (MSR) remains challenges in intensive carbon emissions, retarded hydrogen generation owing to coke deposition over catalysts and huge consumption of water. We herein report an electrochemical splitting of methane (ESM) in molten salts at 500 °C to produce hydrogen in an energy saving, emission‐free and water‐free manner. Following the most energy‐saving route on methane‐to‐hydrogen conversion, methane is electrochemically oxidized at anode to generate carbon dioxide and hydrogen. The generated anodic carbon dioxide is in situ captured by the melts and reduced to solid carbon at cathode, enabling a spatial separation of anodic hydrogen generation from cathodic carbon deposition. Life‐cycle assessment on hydrogen‐generation technologies shows that the ESM experiences an equivalent carbon emission much lower than MSR, and a lower equivalent energy input than alkaline water electrolysis.
A Fast Room‐Temperature Self‐Healing Glassy Polyurethane
Authors: Xu JianHua , Chen JiaoYang , Zhang YaNa , Liu Tong , Fu JiaJun 
Published: January 2021

AbstractWe designed and synthesized a colorless transparent glassy polyurethane assembled using low‐molecular‐weight oligomers carrying a large number of loosely packed weak hydrogen bonds (H‐bonds), which has a glass transition temperature (Tg) up to 36.8 °C and behaves unprecedentedly robust stiffness with a tensile Young's modulus of 1.56±0.03 GPa. Fast room‐temperature self‐healing was observed in this polymer network: the broken glassy polyurethane (GPU) specimen can recover to a tensile strength up 7.74±0.76 MPa after healing for as little as 10 min, which is prominent compared to reported room‐temperature self‐healing polymers. The high density of loose‐packed hydrogen bonds can reversibly dissociate/associate below Tg of GPU (that is secondary relaxation), which enables the reconfiguration of the damaged network in the fractured interfaces, despite the extremely slow diffusion dynamics of molecular chains under room temperature. This GPU shows potential application as an optical lens.
Enzyme‐Loaded Nanoreactors Enable the Continuous Regeneration of Nicotinamide Adenine Dinucleotide in Artificial Metabolisms
Authors: Jo Seong‐Min , Wurm Frederik R. , Landfester Katharina 
Published: January 2021

AbstractNicotinamide adenine dinucleotide (NAD) is an essential coenzyme for numerous biocatalytic pathways. While in nature, NAD+ is continuously regenerated from NADH by enzymes, all synthetic NAD+ regeneration strategies require a continuous supply of expensive reagents and generate byproducts, making these strategies unattractive. In contrast, we present an artificial enzyme combination that produces NAD+ from oxygen and water continuously; no additional organic substrates are required once a minimal amount pyruvate is supplied. Three enzymes, i.e., LDH, LOX, and CAT, are covalently encapsulated into a substrate‐permeable silica nanoreactor by a mild fluoride‐catalyzed sol–gel process. The enzymes retain their activity inside of the nanoreactors and are protected against proteolysis and heat. We successfully used NAD+ from the nanoreactors for the continuous production of NAD+ i) to sense glucose in artificial glucose metabolism, and ii) to reduce the non‐oxygen binding methemoglobin to oxygen‐binding hemoglobin. This latter conversion might be used for the treatment of Methemoglobinemia. We believe that this versatile tool will allow the design of artificial NAD+‐dependent metabolisms or NAD+‐mediated redox‐reactions.
Synthesis of Core@Shell Cu‐Ni@Pt‐Cu Nano‐Octahedra and Their Improved MOR Activity
Authors: Li Can , Chen Xiaobo , Zhang Lihua , Yan Shaohui , Sharma Anju , Zhao Bo , Kumbhar Amar , Zhou Guangwen , Fang Jiye 
Published: January 2021

AbstractFabrication of 3d metal‐based core@shell nanocatalysts with engineered Pt‐surfaces provides an effective approach for improving the catalytic performance. The challenges in such preparation include shape control of the 3d metallic cores and thickness control of the Pt‐based shells. Herein, we report a colloidal seed‐mediated method to prepare octahedral CuNi@Pt‐Cu core@shell nanocrystals using CuNi octahedral cores as the template. By precisely controlling the synthesis conditions including the deposition rate and diffusion rate of the shell‐formation through tuning the capping ligand, reaction temperature, and heating rate, uniform Pt‐based shells can be achieved with a thickness of <1 nm. The resultant carbon‐supported CuNi@Pt‐Cu core@shell nano‐octahedra showed superior activity in electrochemical methanol oxidation reaction (MOR) compared with the commercial Pt/C catalysts and carbon‐supported CuNi@Pt‐Cu nano‐polyhedron counterparts.
Biodegradable Charge‐Transfer Complexes for Glutathione Depletion Induced Ferroptosis and NIR‐II Photoacoustic Imaging Guided Cancer Photothermal Therapy
Authors: Ou Changjin , Na Weidan , Ge Wei , Huang Han , Gao Fan , Zhong Liping , Zhao Yongxiang , Dong Xiaochen 
Published: January 2021

AbstractSuffering from the laborious synthesis and undesirable tumor microenvironment response, the exploitation of novel NIR‐II absorbing organic photothermal agents is of importance to promote phototherapeutic efficacy. Herein, two kinds of charge‐transfer complex nanoparticles (TMB‐F4TCNQ and TMB‐TCNQ) are prepared by supramolecular assembly. Because of the larger energy gap between donor and acceptor, TMB‐F4TCNQ presents higher charge‐transfer degree (72 %) than that of TMB‐TCNQ (48 %) in nanoaggregates. Therefore, TMB‐F4TCNQ exhibits stronger NIR‐II absorption ability with a mass extinction coefficient of 15.4 Lg−1 cm−1 at 1300 nm and excellent photothermal effect. Impressively, the specific cysteine response can make the TMB‐F4TCNQ effectively inhibit the intracellular biosynthesis of GSH, leading to redox dsyhomeostasis and ROS‐mediated ferroptosis. TMB‐F4TCNQ can serve as a contrast agent for NIR‐II photoacoustic imaging to guide precise and efficient photothermal therapy in vivo.
Controllable Self‐Assembly of Peptide‐Cyanine Conjugates In Vivo as Fine‐Tunable Theranostics
Authors: Zheng Rui , Yang Jia , Mamuti Muhetaerjiang , Hou Da‐Yong , An Hong‐Wei , Zhao Yuliang , Wang Hao 
Published: January 2021

AbstractThe fabrication of functional assemblies with defined structures through controllable molecular packing under physiological conditions is challenging. Here, modularly designed peptide‐cyanine conjugates that intracellularly self‐assembly into 1D columnar superstructures with controlled cyanine aggregation were designed, and they exhibit distinct imaging or photothermal properties. The peptide backbone is cleaved by caspase‐3/7 after entering the cells. Then the self‐assembled residue, with a double cyanine substitution (Pr‐2Cy), forms a P helical column in which H‐aggregated cyanine dyes show 3.4‐fold photothermal conversion efficiency compared to free ones. The self‐assembled residue with a single cyanine substitution (Pr‐1Cy) forms a loose column, in which cyanine dyes with undefined structure have a fluorescence quantum yield of up to 9.5 % (emission at 819 nm in H2O). This work provides a simple way to modify in vivo self‐assembled peptides with functional molecules for achieving desired bio‐applications.
Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide‐Functionalized Phosphine Ligands
Authors: Hu Zhiyong , Wei Xiao‐Jing , Handelmann Jens , Seitz Ann‐Katrin , Rodstein Ilja , Gessner Viktoria H. , Gooßen Lukas J. 
Published: January 2021

AbstractThe coupling of aryl chlorides with Reformatsky reagents is a desirable strategy for the construction of α‐aryl esters but has so far been substantially limited in the substrate scope due to many challenges posed by various possible side reactions. This limitation has now been overcome by the tailoring of ylide‐functionalized phosphines to fit the requirements of Negishi couplings. Record‐setting activities were achieved in palladium‐catalyzed arylations of organozinc reagents with aryl electrophiles using a cyclohexyl‐YPhos ligand bearing an ortho‐tolyl‐substituent in the backbone. This highly electron‐rich, bulky ligand enables the use of aryl chlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively over triflate electrophiles, which permits consecutive coupling strategies.
Generation of Elemental Fluorine through the Electrolysis of Copper Difluoride at Room Temperature
Authors: Matsumoto Kazuhiko , Shima Keita , Sugimoto Takuya , Inoue Takahiro , Hagiwara Rika 
Published: January 2021

AbstractThe safe generation of F2gas at room temperature by using simple cell configurations has been the “holy grail” of fluorine research for centuries. Thus, to address this issue, we report generation of F2gas through the electrolysis of CuF2in a CsF‐2.45HF molten salt without the evolution of H2gas. The CuF2is selected through a series of thermodynamic and kinetic assessments of possible metal fluorides. Anode assessments on graphite and glass‐like carbon demonstrate the effect of the absence of the anode during generation of F2gas owing to stabilized operations at room temperature. Although the Ni anode dissolves during electrolysis in the conventional medium‐temperature cell, herein, it facilitates stable electrolysis over 100 h, achieving an F2gas purity of over 99 % with the potential to operate using one‐compartment electrolysis. This work presents a safe and propitious method for the generation of high‐purity F2gas for small‐scale lab and industrial applications.
Boosting Zinc Electrode Reversibility in Aqueous Electrolytes by Using Low‐Cost Antisolvents
Authors: Hao Junnan , Yuan Libei , Ye Chao , Chao Dongliang , Davey Kenneth , Guo Zaiping , Qiao Shi‐Zhang 
Published: January 2021

AbstractAntisolvent addition has been widely studied in crystallization in the pharmaceutical industries by breaking the solvation balance of the original solution. Here we report a similar antisolvent strategy to boost Zn reversibility via regulation of the electrolyte on a molecular level. By adding for example methanol into ZnSO4electrolyte, the free water and coordinated water in Zn2+solvation sheath gradually interact with the antisolvent, which minimizes water activity and weakens Zn2+solvation. Concomitantly, dendrite‐free Zn deposition occurs via change in the deposition orientation, as evidenced by in situ optical microscopy. Zn reversibility is significantly boosted in antisolvent electrolyte of 50 % methanol by volume (Anti‐M‐50 %) even under harsh environments of −20 °C and 60 °C. Additionally, the suppressed side reactions and dendrite‐free Zn plating/stripping in Anti‐M‐50 % electrolyte significantly enhance performance of Zn/polyaniline coin and pouch cells. We demonstrate this low‐cost strategy can be readily generalized to other solvents, indicating its practical universality. Results will be of immediate interest and benefit to a range of researchers in electrochemistry and energy storage.
Complementary Syntheses Giving Access to a Full Suite of Differentially Substituted Phthalocyanine‐Porphyrin Hybrids
Authors: Alkorbi Faeza , Díaz‐Moscoso Alejandro , Gretton Jacob , Chambrier Isabelle , Tizzard Graham J. , Coles Simon J. , Hughes David L. , Cammidge Andrew N. 
Published: January 2021

AbstractPhthalocyanines and porphyrins are often the scaffolds of choice for use in widespread applications. Synthetic advances allow bespoke derivatives to be made, tailoring their properties. The selective synthesis of unsymmetrical systems, particularly phthalocyanines, has remained a significant unmet challenge. Porphyrin‐phthalocyanine hybrids offer the potential to combine the favorable features of both parent structures, but again synthetic strategies are poorly developed. Here we demonstrate strategies that give straightforward, controlled access to differentially substituted meso‐aryl‐tetrabenzotriazaporphyrins by reaction between an aryl‐aminoisoindolene (A) initiator and a complementary phthalonitrile (B). The choice of precursors and reaction conditions allows selective preparation of 1:3 Ar‐ABBB and, uniquely, 2:2 Ar‐ABBA functionalized hybrids.