bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Oxygenation of Hydrocarbons by Mono‐μ‐oxo Dicopper(II) Species Resulting from O−O Cleavage of Tetranuclear CuI/CuII Peroxo Complexes
Authors: Jurgeleit Ramona , Grimm‐Lebsanft Benjamin , Flöser Benedikt Maria , Teubner Melissa , Buchenau Sören , Senft Laura , Hoffmann Jonas , Naumova Maria , Näther Christian , Ivanović‐Burmazović Ivana , Rübhausen Michael , Tuczek Felix 
Published: April 2021

AbstractOne of the challenges of catalysis is the transformation of inert C−H bonds to useful products. Copper‐containing monooxygenases play an important role in this regard. Here we show that low‐temperature oxygenation of dinuclear copper(I) complexes leads to unusual tetranuclear, mixed‐valent μ4‐peroxo [CuI/CuII]2 complexes. These Cu4O2 intermediates promote irreversible and thermally activated O−O bond homolysis, generating Cu2O complexes that catalyze strongly exergonic H‐atom abstraction from hydrocarbons, coupled to O‐transfer. The Cu2O species can also be produced with N2O, demonstrating their capability for small‐molecule activation. The binding and cleavage of O2 leading to the primary Cu4O2 intermediate and the Cu2O complexes, respectively, is elucidated with a range of solution spectroscopic methods and mass spectrometry. The unique reactivities of these species establish an unprecedented, 100 % atom‐economic scenario for the catalytic, copper‐mediated monooxygenation of organic substrates, employing both O‐atoms of O2.
Expedient Dual Co/Organophotoredox Catalyzed Stereoselective Synthesis of All‐Carbon Quaternary Centers
Authors: Cristòfol Àlex , Limburg Bart , Kleij Arjan W. 
Published: April 2021

AbstractAn efficient and attractive Co/organophotoredox dual catalysis protocol has been developed allowing the stereoselective access to a wide variety of syn‐configured 1,3‐diols featuring quaternary carbon centers. The synthesis of the target molecules is achieved under ambient reaction conditions using modular and accessible reagents, substituted vinyl cyclic carbonates and aldehydes, and in short reaction times. Mechanistic control experiments suggest that the stereoselectivity can be rationalized via a preferred Zimmerman–Traxler transition state comprising a Co(allyl) species and an activated aldehyde. This newly developed process thus expands the use of base metal catalysis in the construction of challenging quaternary carbon stereocenters.
Observation of Borane–Olefin Proximity Interaction Governing the Structure and Reactivity of Boron‐Containing Macrocycles
Authors: Murata Yukihiro , Matsunagi Kenta , Kashida Junki , Shoji Yoshiaki , Özen Cihan , Maeda Satoshi , Fukushima Takanori 
Published: April 2021

AbstractWhile attractive interactions between borane and olefin have been postulated to trigger various boron‐mediated organic transformations, proximity structures of these functional groups, other than the formation of weak van der Waals complexes, have never been directly observed. Here we show that a close intramolecular borane–olefin interaction operates in macrocyclic systems containing borane and olefinic groups obtained by multi‐step 1,2‐carboboration between a strained alkyne and 9‐borafluorene derivatives. Depending on Lewis acidity of the borane moiety and the size of the macrocycles, the magnitude of interaction changes, resulting in different reaction modes. The whole picture of the multi‐step reactions has been revealed experimentally with theoretical supports. The present finding may not only provide a deeper understanding of the fundamental boron‐mediated interaction but also lead to the development of new organic transformations involving molecular activation by boranes.
Response to “What Shall We Do with Computed Detonation Performance? Comment on ‘1,3,4‐Oxadiazole Bridges: A Strategy to Improve Energetics at the Molecular Level’”
Authors: Ma Jinchao , Chinnam Ajay Kumar , Cheng Guangbin , Yang Hongwei , Zhang Jiaheng , Shreeve Jean'ne M. 
Published: April 2021

AbstractThe values obtained for detonation performance are a function of the computational methods utilized. Since there are many such methods, the literature may contain a range of values for a single compound.
Biodiesel production from milk thistle seed oil as nonedible oil by cosolvent esterification–transesterification process
Authors: Saeed Liqaa I. , Khalaf Ahmed M. , Fadhil Abdelrahman B. 
Published: April 2021

AbstractThe crude oil extracted from milk thistle seeds was employed as a precursor for creating biodiesel (BD) via the cosolvent esterification–transesterification process. The high acid value of the extracted oil (11.90 mg KOH/g) encouraged its pre‐esterification in the occurrence of hexane as a cosolvent. The cosolvent esterification of oil diminished its acidity index to below 2.0 mg KOH/g using 1.5:1 hexane:methanol volume ratio, 50°C, 60‐min reaction time, 6:1 methanol:oil molar ratio, and 0.75 wt.% HCl. Alcoholysis reaction of the esterified oil with methanol and a blend of methanol:ethanol to synthesize, respectively, methylic BD and methylic/ethylic BD was accomplished in the presence of hexane as a cosolvent as well. Under the ideal reaction conditions, methylic BD yield and methylic/ethylic BD yield were 96.23% and 95.63%, respectively. The Fourier‐transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR) spectra affirmed the lipid transformation from milk thistle seeds into BD. The attained samples of BD exhibited properties conforming to those specified by ASTM D6751. Also, the cosolvent methanolysis kinetic obeyed the pseudo‐first‐order with 35.94 KJ/mol activation energy and 6.32‐s frequency factor.
Characterization and antimicrobial properties of ferulic acid grafted self‐assembled bacterial cellulose‐chitosan membranes
Authors: Shen Runyan , Wang Haijun , Wu Kaizhang , Gao Jie , Li Jianbin 
Published: April 2021

AbstractBacterial cellulose (BC) is a biomaterial with many excellent properties, but its application as a food packaging and biomedical material is limited due to its lack of antibacterial properties. In this study, ferulic acid (FA) grafted self‐assembled bacterial cellulose‐chitosan (BCF) membranes were prepared by soaking BC films in chitosan‐ferulic acid (CF) solution to synthesize antibacterial biomaterials. 1H NMR confirmed that FA grafted onto chitosan successfully. The results of field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, and tensile analysis showed that CF were successfully incorporated into BC matrix and the BCF membranes had good physical properties. The antibacterial experiments demonstrated that BCF membranes had an excellent antibacterial effect against Staphylococcus aureus and Escherichia coli. Therefore, combining all these properties, BCF composite membranes would have potential application in food packaging or wound‐healing materials.
Polyoxometalates/polymer composites for the photodegradation of bisphenol‐A
Authors: Brahmi Chaima , Benltifa Mahmoud , Ghali Mariem , Dumur Frédéric , Simonnet‐Jégat Corine , Monnier Valérie , Morlet‐Savary Fabrice , Bousselmi Latifa , Lalevée Jacques 
Published: April 2021

AbstractNowadays water scarcity represents a threat for human and living beings. Therefore, to satisfy the demands of people for clean and safe water, new technologies for wastewater treatment have been developed. Thus, photocatalysis has emerged as a green chemical approach for such treatment. In this context, new polyoxometalate (POM)/polymer composites with relevant photocatalytic properties have been developed via an easy and cheap photopolymerization process upon mild visible light irradiation at 405 nm. This fruitful association between POM and polymer allowed the obtention of shaped materials facile to collect and reuse at the end of the photocatalytic treatment avoiding then the usual time‐consuming regeneration methods. The prepared photocomposites displayed excellent photocatalytic performance for the removal of bisphenol‐A from water under different sources of irradiation. Hence, 100%, 88%, and 50% of this model compound were decomposed by the phosphomolybdic composite under just 90 min of UV lamp, solar and LED@375 nm irradiations, respectively. The effectiveness of these developed photocatalysts towards the degradation of other organic compounds, as well as the degradation mechanism based on the generation of highly reactive chemicals such as •OH radicals promoting the degradation were already reported. Bisphenol‐A degradation pathway and the identification of the photoproducts were discussed using mass spectroscopy technique. Therefore, this paper highlighted the photocatalytic efficiency of the new manufactured materials for the photodegradation of the bisphenol‐A, thus expanding their application fields, under different sources of irradiation and under pure solar irradiation which make their applications more interesting and less energy consuming.
Results on controllability of Hilfer fractional differential equations with infinite delay via measures of noncompactness
Authors: Kavitha K. , Vijayakumar V. , Udhayakumar R. , Ravichandran C. 
Published: April 2021

AbstractThis manuscript mainly focuses on the controllability of Hilfer fractional differential system with infinite delay. We study our primary outcomes by employing fractional calculus, measures of noncompactness, and fixed‐point approach. Then, we extend our results to the concept of nonlocal conditions. Lastly, an example is given for illustration of theory.
Heterogeneous Solid‐Electrolyte Interphase in Graphite Electrodes Assessed by 4D‐Resolved Computational Simulations
Authors: Chouchane Mehdi , Arcelus Oier , Franco Alejandro A. 
Published: April 2021

AbstractGraphite is one of the most used active materials in lithium‐ion battery negative electrodes thanks to its high specific capacity and low equilibrium potential. For over 40 years, one of the most discussed issues with this material revolves around the complex formation mechanism of the solid‐electrolyte interphase (SEI), which acts as a protective layer against electrolyte decomposition but causes capacity losses. Due to the difficulties to experimentally observe the SEI (air sensibility, low contrast and nanometric size), its impact on the performance of graphite‐based porous electrodes has never been spatially assessed in regards of the three‐dimensional features of the electrodes. We report here a new 4D (3D+time) resolved computational model which gives insights about the SEI heterogeneity within such porous electrodes. The model is applied to different graphite morphologies and is able to assess the electrode mesostructure impact on the SEI formation and the impact of the latter on the electrodes’ electrochemical performance. This work paves the way towards a powerful tool to assist in the interpretation of SEI characterization experiments.
Can ketone bodies inactivate coronavirus spike protein? The potential of biocidal agents against SARS‐CoV‐2
Authors: Shaheen Alaa 
Published: April 2021

AbstractBiocidal agents such as formaldehyde and glutaraldehyde are able to inactivate several coronaviruses including SARS‐CoV‐2. In this article, an insight into one mechanism for the inactivation of these viruses by those two agents is presented, based on analysis of previous observations during electron microscopic examination of several members of the orthocoronavirinae subfamily, including the new virus SARS‐CoV‐2. This inactivation is proposed to occur through Schiff base reaction‐induced conformational changes in the spike glycoprotein leading to its disruption or breakage, which can prevent binding of the virus to cellular receptors. Also, a new prophylactic and therapeutic measure against SARS‐CoV‐2 using acetoacetate is proposed, suggesting that it could similarly break the viral spike through Schiff base reaction with lysines of the spike protein. This measure needs to be confirmed experimentally before consideration. In addition, a new line of research is proposed to help find a broad‐spectrum antivirus against several members of this subfamily.
Ultrafast dynamics on fluorescence quenching of rhodamine 6G by graphene oxide
Authors: Liu Dunli , Wang Qiuyun , Chen Anmin , Li Qingyi , Sui Laizhi , Jin Mingxing 
Published: April 2021

AbstractFluorescence quenching of rhodamine 6G by graphene oxide (GO) was investigated using steady‐state fluorescence spectroscopy and ultrafast time‐resolved absorption spectroscopy. The steady‐state fluorescence spectra showed that rhodamine 6G fluorescence was effectively quenched by titrating the GO to the rhodamine 6G solutions. For lower GO concentrations, transient dynamic curves followed two‐exponential decay parameters. For higher GO concentrations, the dynamic curves could not be fitted well, and three‐exponential decay parameters were appropriate. The results indicated that there was a new transition process (electron transfer) in the exited rhodamine 6G and GO solution.
Telocytes of the male urogenital system: Interrelationships, possible functions, and pathological implications
Authors: Sanches Bruno Domingos Azevedo , Tamarindo Guilherme Henrique , Maldarine Juliana Dos Santos , Da Silva Alana Della Torre , Dos Santos Vitória Alário , Góes Rejane Maira , Taboga Sebastião Roberto , Carvalho Hernandes F. 
Published: April 2021

AbstractThe male urogenital system is composed of the reproductive system and the urinary tract; they have an interconnected embryonic development and share one of their anatomical components, the urethra. This system has a highly complex physiology deeply interconnected with the circulatory and nervous systems, as well as being capable of adapting to environmental variations; it also undergoes changes with aging and, in the case of the reproductive system, with seasonality. The stroma is an essential component in this physiological plasticity and its complexity has increased with the description in the last decade of a new cell type, the telocyte. Several studies have demonstrated the presence of telocytes in the organs of the male urogenital system and other systems; however, their exact function is not yet known. The present review addresses current knowledge about telocytes in the urogenital system in terms of their locations, interrelationships, possible functions and pathological implications. It has been found that telocytes in the urogenital system possibly have a leading role in stromal tissue organization/maintenance, in addition to participation in stem cell niches and an association with the immune system, as well as specific functions in the urogenital system, lipid synthesis in the testes, erythropoiesis in the kidneys and the micturition reflex in the bladder. There is also evidence that telocytes are involved in pathologies in the kidneys, urethra, bladder, prostate, and testes.
A Synergistic Strategy with 3D Highly Conductive Carbon Matrix‐Decorated with Low Loading of CdS Quantum Dots as a Sulfur Host for Advanced Li−S Batteries
Authors: Li Yangping , Xu Jie , Xu Da , He Yun , Sun Xinyi , Niu Dongfang , Zhang Xinsheng 
Published: April 2021

AbstractLithium‐sulfur batteries (LSBs) have become one of the most competitive candidates for next generation energy storage systems due to the high theoretical energy density, nevertheless, the severe shuttle effect, volume expansion, and poor electrical conductivity restrict their practical application. Herein, we report a synergistic combination of 3D carbon matrix (CdS@NG‐CNT) composed of low‐defect carbon nanotubes (CNTs) and nitrogen‐doped graphene (NG) decorated with low loading of cadmium sulfide quantum dots as sulfur host and carbon black (CB) as separator layer to collectively solve these issues. Specifically, the developed host material possesses abundant macropores and mesopores and high electrical conductivity, which endow the carbon matrix multifaceted structural properties for polysulfides immobilization, electrons/Li+ transfer, and Li2S formation, as well as buffering the volume expansion during cycling. The CB‐modified separator can help to enhance the interconversion of intercepted polysulfides. Benefiting from these aspects, the cell equipped with CdS@NG‐CNT/S//CB‐PP exhibits a superior rate capacity of 1493.6 mA h/g at 0.2 C (1st), and maintains a capacity of 479.7 mA h/g after 1050 cycles with an ultralow capacity decay rate of 0.051 % at 1.0 C. This work provides a useful strategy to solve issues of the current LSBs, which may practically be used in the high‐energy density.
On the Differential Capacitance and Potential of Zero Charge of Au(111) in Some Aprotic Solvents
Authors: Shatla Ahmed S. , Landstorfer Manuel , Baltruschat Helmut 
Published: April 2021

AbstractVoltammetric and Gouy‐Chapman capacitance minimum measurements were conducted on Au(111) and roughened Au(111) electrodes in aprotic electrolytes in the absence and presence of specifically adsorbed ions for concentrations ranging from 0.001 to 0.5 M. Negative of the point of zero charge (pzc), the capacitance maximum increases in the order Ca2+<Li+<K+, but the pzc value is independent of cation nature. The capacitance values have a slight dependence on cation type at a more negative potential. The pzc depends on the solvent and is influenced by the dielectric constant, metal‐solvent interactions and donor number; it is shifted to more positive values with increasing water content. Specific anion adsorption shifts the pzc to more negative values. The pzc value is more negative for the roughened electrode compared to the single crystal electrode. Propylene carbonate (PC) adsorption in the presence of perchlorate and iodide was examined on gold film by surface‐enhanced infrared absorption spectroscopy (SEIRAS). The potential dependent intensity is explained by a stronger electric field and thus a better alignment of the PC molecules when the absolute potential difference to the pzc is large.The capacitance curves were theoretically modelled. From the capacitance maxima on both sides of the pzc the ionic volume and thus the solvation numbers were estimated. The width of the capacitance minimum is believed to be related to the layer of adsorbed solvent molecules.
An Ultrastable Crystalline Acylhydrazone‐Linked Covalent Organic Framework for Efficient Removal of Organic Micropollutants from Water
Authors: Zhao Yuling , Zhao Yue , Wu Cailing , Qiu Jikuan , Wang Huiyong , Li Zhiyong , Zhao Yang , Wang Jianji 
Published: April 2021

AbstractAs an important member of crystalline porous polymers, acylhydrazone‐linked covalent organic frameworks (COFs) have gained much attention in recent years. However, the low structural stability imparts a limit on their practical applications. To tackle this problem, we report a simple strategy to increase the chemical stability of acylhydrazone‐linked COFs by incorporating azobenzene groups in the conjugated framework. Through reinforcing the π‐π stacking interactions between the adjacent layers with increased π‐surface, it is surprising to find that the resulting materials exhibit extreme stability in harsh environments, such as in strong acid, strong base, aqueous educing agent and boiling water, even exposed to air for one year. As a proof‐of‐concept, such frameworks have been used to remove various organic micropollutants such as antibiotics, plastic components, endocrine disruptors, and carcinogens from water with high capacity, fast speed and excellent reusability over a wide pH range at environmentally relevant concentrations. The results provide a new avenue to significantly enhance the stability of COFs for practical applications.
1,2‐Carbopentafluorophenylation of Alkynes: The Metallomimetic Pull‐Push Reactivity of Tris(pentafluorophenyl)borane
Authors: Shibuya Masatoshi , Matsuda Miki , Yamamoto Yoshihiko 
Published: April 2021

AbstractWe report the novel single‐step 1,2‐dicarbofunctionalization of an arylacetylene with an allylsilane and tris(pentafluorophenyl)borane [B(C6F5)3] involving C−C bond formation with C−H bond scission at the β‐position to the silicon atom of an allylsilane and B→C migration of a C6F5 group. The 1,2‐carbopentafluorophenylation occurs smoothly without the requirement for a catalyst or heating. Mechanistic studies suggest that the metallomimetic “pull‐push” reactivity of B(C6F5)3 imparts consecutive electrophilic and nucleophilic characteristics to the benzylic carbon of the arylacetylene. Subsequent photochemical 6π‐electrocyclization affords tetrafluoronaphthalenes, which are important in the pharmaceutical and materials sciences. Owing to the unique reactivity of B(C6F5)3, the 1,2‐carbopentafluorophenylation using 2‐substituted furan proceeded with ring opening, and the reaction using silyl enolates formed a C−C bond with C−O bond scission at the silyloxy‐substituted carbon.
Highly Stereoselective Positional Isomerization of Styrenes viaAcid‐Catalyzed Carbocation Mechanism
Authors: Hu Xiao‐Si , He Jun‐Xiong , Zhang Ying , Zhou Jian , Yu Jin‐Sheng 
Published: April 2021

Main observation and conclusionThe first transition metal‐free highly stereoselective positional isomerization of various α‐alkyl styrenes through a carbocation mechanism triggered strategy is developed by using Al(OTf)3 as a hidden Brønsted acid catalyst, which provides facile access to value‐added acyclic tri‐ and tetra‐substituted alkenes in good yields with high stereoselectivity under mild conditions. The practicality of this protocol is further highlighted by the gram‐scale synthesis, high stereoselectivity, good functional group tolerance, and simple operation. Mechanistic studies support that Al(OTf)3 acts as a hidden Brønsted acid catalyst and a carbocation intermediate is formed.
Interaction of a Triantennary Quinoline Glycoconjugate with the Asialoglycoprotein Receptor
Authors: Palit Subhadeep , Banerjee Sayanika , Mahata Tridib , Niyogi Sougata , Das Tanusree , Sova Mandi Chandra , Chakrabarti Partha , Dutta Sanjay 
Published: April 2021

AbstractTargeted intracellular delivery is an efficient strategy for developing therapeutics against cancer and other intracellular infections. Nonspecific drug delivery shows limited clinical applications owing to high dosage, cytotoxicity, nonspecific action, high cost, etc. Therefore, targeted delivery of less cytotoxic drug candidates to hepatocytes through ASGPR‐mediated endocytosis could be an efficient strategy to surmount the prevailing shortcomings. In the present work, the gene encoding ASGPR‐H1‐CRD was amplified from Huh7 cells, cloned into pET 11a vector, and the ASGPR‐H1‐CRD protein was expressed and purified from E. coli. A novel triantennary galactose‐conjugated quinoline derivative 4 was synthesized that demonstrates 17‐fold higher binding affinity to isolated ASGPR‐H1‐CRD protein receptor (Kd∼54 μM) in comparison to D‐galactose (Kd∼900 μM). Moreover, micro‐calorimetric studies for the interaction of glycoconjugate 4 with ASGPR protein on live hepatocytes showed notable thermal response in case of ASGPR‐containing Huh7 cells, in comparison to non‐ASGPR Chang cells. These results might serve as an approach towards targeted delivery of small glycoconjugates to hepatocytes.