Publications by authors named "Haichao Xu"

Despite the increasing interest in radical-based fluoroalkylation techniques, the organofluorine compounds bearing the partially fluorinated hexafluoroisopropyl group remain extremely scarce due to the lack of appropriate reagents. Herein we report an unprecedented photoelectrocatalytic method for the C-H hexafluoroisopropylation of indoles and tryptophan peptides, utilizing the readily available hexafluoro-2-propanol (HFIP) as the fluoroalkylation reagent. In this process, HFIP is converted into hexafluoroisopropyl radicals, enabling fluoroalkylation reactions.

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ConspectusMolecular photoelectrocatalysis, which combines the merits of photocatalysis and organic electrosynthesis, including their green attributes and capacity to offer novel reactivity and selectivity, represents an emerging field in organic chemistry that addresses the growing demands for environmental sustainability and synthetic efficiency. This synergistic approach permits access to a wider range of redox potentials, facilitates redox transformations under gentler electrode potentials, and decreases the use of external harsh redox reagents. Despite these potential advantages, this area did not receive significant attention until 2019, when we and others reported the first examples of modern molecular photoelectrocatalysis.

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Article Synopsis
  • Emergent superconductivity at LaAlO/KTaO interfaces is influenced by the crystallographic orientations of KTaO, creating a mystery in its behavior.
  • Using soft X-ray angle-resolved photoemission spectroscopy, researchers analyzed the electronic structure of both superconducting and non-superconducting interfaces, finding that mobile electrons exhibit strong k dispersion and exist in a quasi-three-dimensional electron gas.
  • The study reveals that the electron-phonon coupling is orientation-dependent, with stronger coupling linked to higher superconducting transition temperatures, offering insights into how orientation affects electron interactions at oxide interfaces.
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  • Superconducting infinite-layer nickelates present a unique opportunity to explore high-temperature superconductivity, with ongoing debates regarding their electronic mechanics due to complex structures.
  • Recent advancements in angle-resolved photoemission spectroscopy allowed researchers to directly study the electronic structures of both the parent compound LaNiO and the superconducting LaCaNiO.
  • Findings reveal distinct Fermi surfaces and band structures that resemble those of cuprate superconductors, but with notable differences in hole doping between the two, shedding light on the superconducting mechanisms of nickelates.
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  • Interfacing single-unit cell (1 UC) FeSe with TiO or FeO significantly boosts its superconductivity compared to bulk FeSe, primarily due to enhanced interfacial electron-phonon coupling (EPC).
  • The introduction of a new interface, 1 UC FeSe/SrVO/SrTiO, shows that the metallic properties of SrVO effectively screen high-energy phonons, which is a first for FeSe/oxide systems while keeping the 1 UC thickness.
  • Despite similar doping levels, the new 1 UC FeSe/SrVO interface has a lower pairing temperature (∼ 48 K) than other interfaces, highlighting the complex roles of interfacial EPC and dimensional
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The discovery of interfacial superconductivity in monolayer FeSe/oxides has spurred intensive research interest. Here we not only extend the FeSe/FeO superconducting interface to FeSe/NdFeO but also establish robust interface-enhanced superconductivity at a very low doping level. Specifically, well-annealed FeSe/NdFeO exhibits a low doping level of 0.

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In the field of catalytic asymmetric synthesis, the less-treated path lies in oxidative catalytic asymmetric transformations. The hurdles of pinpointing the appropriate chemical oxidants and addressing their compatibility issues with catalysts and functionalities present significant challenges. Organic electrochemistry, employing traceless electrons for redox reactions, is underscored as a promising solution.

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Objective: Pulp regeneration with bioactive dentin-pulp complex has been a research hotspot in recent years. Stem cell therapy provided an interest strategy to regenerate the dental-pulp complex. Hence, this study aimed to evaluate the effects of photosensitive gelatin methacrylate (GelMA) hydrogel encapsulating dental pulp stem cells (DPSCs) and silver nanoparticles (AgNPs) for dental pulp regeneration in vitro.

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The difunctionalization of alkenes-a process that installs two functional groups in a single operation and transforms chemical feedstocks into value-added products-is one of the most appealing synthetic methods in contemporary chemistry. However, the introduction of two distinct functional groups via two readily accessible nucleophiles remains a formidable challenge. Existing intermolecular alkene azidocyanation methods, which primarily focus on aryl alkenes and rely on stoichiometric chemical oxidants.

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The selective oxygenation of ubiquitous C(sp )-H bonds remains a highly sought-after method in both academia and the chemical industry for constructing functionalized organic molecules. However, it is extremely challenging to selectively oxidize a certain C(sp )-H bond to afford alcohols due to the presence of multiple C(sp )-H bonds with similar strength and steric environment in organic molecules, and the alcohol products being prone to further oxidation. Herein, we present a practical and cost-efficient electrochemical method for the highly selective monooxygenation of benzylic C(sp )-H bonds using continuous flow reactors.

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The asymmetric difunctionalization of alkenes, a method transforming readily accessible alkenes into enantioenriched chiral structures of high value, has long been a focal point of organic synthesis. Despite tremendous efforts in this domain, it remains a considerable challenge to devise enantioselective oxidative dicarbofunctionalization of alkenes, even though these transformations can utilize stable and unfunctionalized functional group donors. In this context, we report herein a photoelectrocatalytic method for the enantioselective heteroarylcyanation of aryl alkenes, which employs unfunctionalized heteroarenes through C-H functionalization.

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The development of efficient and sustainable methods for decarboxylative transformations is of great importance due to the ease of availability and nontoxicity of carboxylic acids. Despite tremendous efforts in this area, it remains challenging to develop enantioselective transformations direct from carboxylic acids. Herein we disclose a photoelectrocatalytic method for the direct and enantioselective decarboxylative cyanation.

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Health geography provides a relational approach to understanding elders' wellbeing experience in relation to place. That the migrating grandparents move between their home and their adult children's home to support their children's life in the migrating city provides a particular pattern to supplement the place-based wellbeing literature. How they negotiate their wellbeing remains to be observed in the daily home-making practices related to their two homes.

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The direct hydroxylation of arene C-H bonds is a highly sought-after transformation but remains an unsolved challenge due to the difficulty in efficient and regioselective C-H oxygenation and high reactivity of the phenolic products leading to overoxidation. Herein we report electrochemical C-H hydroxylation of arenes in continuous flow for the synthesis of phenols. The method is characterized by broad scope (compatible with arenes of diverse electronic properties), mild conditions without any catalysts or chemical oxidants, and excellent scalability as demonstrated by the continuous production of 1 mol (204 grams) of one of the phenol products.

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The 1,2-diamine motif is prevalent in natural products, small-molecule pharmaceuticals, and catalysts for asymmetric synthesis. Transition metal catalyzed alkene diazidation has evolved to be an attractive strategy to access vicinal primary diamines but remains challenging, especially for practical applications, due to the restriction to a certain type of olefins, the frequent use of chemical oxidants, and the requirement for high loadings of metal catalysts (1 mol % or above). Herein we report a scalable Cu-electrocatalytic alkene diazidation reaction with 0.

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Objective: Retrospective study on the safety and efficacy of anlotinib in the treatment of advanced leiomyosarcoma in real-world.

Methods: Clinical data were collected from patients suffered from advanced leiomyosarcoma who received anlotinib treatment in Cancer Hospital of the University of Chinese Academy of Sciences from January 2018 to December 2020. Objective response rate (ORR) and disease control rate (DCR) were analyzed according to the RECIST 1.

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The performance of methylated in lower gastrointestinal (GI) cancer (colorectal cancer) has been extensively investigated; however, its performance in upper GI cancer (esophageal cancer and gastric cancer) and the comparison with lower GI cancer have rarely been studied. A total of 1854 subjects, including 344 upper GI cancer patients, 459 lower GI cancer patients, and 1051 noncancer subjects, were recruited in this prospective cohort study. A modified single polymerase chain reaction test for detecting was used for plasma detection.

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The direct functionalization of allylic C-H bonds with nucleophiles minimizes pre-functionalization and converts inexpensive, abundantly available materials to value-added alkenyl-substituted products but remains challenging. Here we report an electrocatalytic allylic C-H alkylation reaction with carbon nucleophiles employing an easily available cobalt-salen complex as the molecular catalyst. These C(sp )-H/C(sp )-H cross-coupling reactions proceed through H evolution and require no external chemical oxidants.

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Cyclopropane is a prevalent structural unit in natural products and bioactive compounds. While the transition metal-catalyzed alkene cyclopropanation of functionalized compounds such as α-diazocarbonyl derivatives has been well established and provides straightforward access to cyclopropanes, cyclopropanation directly from the more stable and simpler methylene compounds has remained an unsolved challenge despite the highly desirable benefits of minimal prefunctionalization and increased operational safety. Herein we report an electrocatalytic strategy for the cyclopropanation of active methylene compounds, employing an organic catalyst.

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Two-dimensional metal-organic nanosheets (2D MONs) are an emerging class of ultrathin, porous, and crystalline materials. The organic/inorganic hybrid nature offers MONs distinct advantages over other inorganic nanosheets in terms of diversity of organic ligands and metal notes. Compared to bulk three-dimensional metal-organic frameworks, 2D MONs possess merits of high density and readily accessible catalytic sites, reduced diffusion pathways for reactants/products, and fast electron transport.

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Organic electrosynthesis has been widely used as an environmentally conscious alternative to conventional methods for redox reactions because it utilizes electric current as a traceless redox agent instead of chemical redox agents. Indirect electrolysis employing a redox catalyst has received tremendous attention, since it provides various advantages compared to direct electrolysis. With indirect electrolysis, overpotential of electron transfer can be avoided, which is inherently milder, thus wide functional group tolerance can be achieved.

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Electrocatalytic dehydrogenative C(sp)-H/C(sp)-H cross-coupling of tetrahydroisoquinolines with terminal alkynes has been achieved in a continuous-flow microreactor through 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)/copper relay catalysis. The reaction is easily scalable and requires low concentration of supporting electrolyte and no external chemical oxidants or ligands, providing straightforward and sustainable access to 2-functionalized tetrahydroisoquinolines.

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This study aimed to explore the roles and relationship between FUsed in Sarcoma (FUS)-C/EBP HOmologous Protein (CHOP), microRNA (miR)-486 and cyclin dependent kinase 4 (CDK4) in myxoid liposarcoma, and determined whether FUS-CHOP can regulate proliferation and apoptosis of myxoid liposarcoma cells by regulating miR-486/CDK4 axis. The levels of miR-486, CDK4 and FUS-CHOP in myxoid liposarcoma samples/adjacent normal muscle tissues and myxoid liposarcoma/human adipose-derived stem cell line were evaluated using reverse transcription-quantitative polymerase chain reaction and western blotting. Cell proliferation and apoptosis were performed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and flow cytometry, respectively.

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The development of efficient and sustainable methods for carbon-phosphorus bond formation is of great importance due to the wide application of organophosphorus compounds in chemistry, material sciences and biology. Previous C-H phosphorylation reactions under nonelectrochemical or electrochemical conditions require directing groups, transition metal catalysts, or chemical oxidants and suffer from limited scope. Herein we disclose a catalyst- and external oxidant-free, electrochemical C-H phosphorylation reaction of arenes in continuous flow for the synthesis of aryl phosphorus compounds.

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