49,926 results match your criteria Angewandte Chemie-International Edition[Journal]


Alternating Terpolymers through Cyclopolymerization and Subsequent Orthogonal Functionalization.

Angew Chem Int Ed Engl 2022 May 27. Epub 2022 May 27.

Westfalische Wilhelms-Universitat Munster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149, Münster, GERMANY.

A method for the synthesis of functionalized alternating copolymers by reversible deactivation radical polymerization was developed. Copolymerization by reversible addition-fragmentation chain transfer of hexenyl vinyl ether with a novel fluorinated divinyl monomer yields alternating cyclopolymers that can be chemoselectively modified by three distinct orthogonal functionalization reactions. Along the thiol-ene click reaction and amidation, a third functionalization was achieved via NHC-catalyzed transesterification or acylation resulting in a small library of ABC-type alternating terpolymers. Read More

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Merging the Non-Natural Catalytic Activity of Lipase and Electrosynthesis: Asymmetric Oxidative Cross-Coupling of Secondary Amines with Ketones.

Angew Chem Int Ed Engl 2022 May 27. Epub 2022 May 27.

Southwest University, School of Chemistry and Chemical Engineering, No. 1, Tiansheng Rd., 400715, Chongqing, CHINA.

We describe the enantioselective oxidative cross-coupling of secondary amines with ketones by combining the non-natural catalytic activity of lipase with electrosynthesis. Various 2,2-disubstituted 3-carbonyl indoles with a stereogenic quaternary carbon center were synthesized from 2-substituted indoles in yields up to 78% with good enantio- and diastereoselectivities (up to 96:4 e.r. Read More

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Intramolecular C-H Activation as an Easy Toolbox to Synthesize Pyridine-Fused Bipolar Hosts for Blue Organic Light-Emitting Diodes.

Angew Chem Int Ed Engl 2022 May 27. Epub 2022 May 27.

Sichuan University, College of Chemistry, 29 Wangjiang Road, 610064, Chengdu, CHINA.

The development of high-performance blue organic light-emitting diodes (OLEDs) remains a challenging task. While exploiting new blue emitters has attracted great interest, developing host materials that considerably determine device performance obviously lags behind. Herein, we present an ease of access to the structurally diverse benzoheteroaromatic-fused pyridine skeletons by the iridium-catalyzed intramolecular C-H/C-H coupling reaction, which unlocks an unparalleled opportunity to rapidly assemble a library of pyridine-fused bipolar host materials. Read More

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Atroposelective Construction of Nine-Membered Carbonate Bridged Biaryls.

Angew Chem Int Ed Engl 2022 May 27. Epub 2022 May 27.

Chongqing University, Innovative Drug Research Center, No.55 Daxuecheng South Rd, 401331, Chongqing, CHINA.

We herein demonstrated an efficient method for the atroposelective construction of nine-membered carbonate bridged biaryls through vinylidene ortho-quinone methide (VQM) intermediates. Diverse products with desirable pharmacological features were synthesized in satisfying yields and good to excellent enantioselectivities. In subsequent bioassays, several agents showed considerable antiproliferative activity via the mitochondrial-related apoptosis mechanism. Read More

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Synthesis of an N-Heterocylic Boryl-Stabilized Disilyne and its Application to the Activation of Dihydrogen and C-H Bonds.

Angew Chem Int Ed Engl 2022 May 27. Epub 2022 May 27.

Nankai University, Institute of Elemento-Organic Chemistry, 94 Weijin Road, 300071, Tianjin, CHINA.

The synthesis of low-valent silicon compounds that enable the activation of small molecules has been of great current interest. Reduction of N-heterocyclic boryltribromosilane (NHB)SiBr 3 ( 2 , NHB = [ArN(CMe) 2 NAr]B, Ar = 2,6- i Pr 2 C 6 H 3 ) with three equiv. of lithium in diethyl ether yielded the NHB-stabilized disilyne (NHB)Si≡Si(NHB) ( 3 ). Read More

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Ultrafast Triplet-Singlet Exciton Interconversion in Narrowband Blue Organoboron Emitters Doped with Heavy Chalcogens.

Angew Chem Int Ed Engl 2022 May 26. Epub 2022 May 26.

Kyushu University, Institute for Advanced Study, 744 Motooka, Nishi-ku, 819-0395, Fukuoka, JAPAN.

Narrowband emissive organoboron emitters featuring the multi-resonance (MR) effect have now become a critical material component for constructing high-performance organic light-emitting diodes (OLEDs) with pure emission colors. These MR organoboron emitters are capable of exhibiting high-efficiency narrowband thermally activated delayed fluorescence (TADF) by allowing triplet-to-singlet reverse intersystem crossing (RISC). However, RISC involving spin-flip exciton upconversion is generally the rate-limiting step in the overall TADF; hence, a deeper understanding and precise control of the RISC dynamics are ongoing crucial challenges. Read More

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Bipolar Magnetic Molecules for Spin-Polarized Electric Current in Molecular Junctions.

Angew Chem Int Ed Engl 2022 May 26. Epub 2022 May 26.

USTC: University of Science and Technology of China, Department of Chemical Physics, CHINA.

Electrical control of spin transport at single molecule level is highly desired for molecular nanospintronics. By exploiting magnetic bistability of spin crossover complexes, the magnitude of spin polarization can be modulated. However, efficiently controlling the direction of spin polarization at single molecule level is still challenging. Read More

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Green-Light-Driven Reductive Elimination of Chlorine from a Carbene-Xanthylium Gold(III) Complex.

Angew Chem Int Ed Engl 2022 May 26. Epub 2022 May 26.

Texas A&M University, Chemistry, TAMU 3255, 77843-3255, College Station, UNITED STATES.

With the discovery of late transition metal platforms that support clean photoreductive halogen eliminations, we now describe an indazol-3-ylidene gold trichloride complex ([ 7 ] + ) decorated at the 4-position by a xanthylium unit. This orange complex features a low energy band in the visible part of the spectrum, assigned to the charge transfer excitation of the indazol-3-ylidene/xanthylium donor/acceptor dyad. Green-light irradiation of this complex in the presence of a chlorine trap elicits the clean photoelimination of chlorine radicals, producing the corresponding gold(I) complex. Read More

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Guest-modulated Circularly Polarized Luminescence by Ligand-to-Ligand Chirality Transfer in Heteroleptic Pd(II) Coordination Cages.

Angew Chem Int Ed Engl 2022 May 26. Epub 2022 May 26.

TU Dortmund University, Faculty for Chemistry and Chemical Biology, Otto-Hahn-Str. 6, 44227, Dortmund, GERMANY.

Multicomponent metallo-supramolecular assembly allows to rationally combine different building blocks. Discrete multifunctional hosts with an accessible cavity can be prepared in a non-statistical fashion. We employ our shape-complementary assembly (SCA) method to achieve for the first time integrative self-sorting of heteroleptic PdII cages showing guest-tunable circularly polarized luminescence (CPL). Read More

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A Modular Approach for Diversity-Oriented Synthesis of 1,3-trans-Disubstituted Tetrahydroisoquinolines: Seven-Step Asymmetric Synthesis of Michellamines B and C.

Angew Chem Int Ed Engl 2022 May 26. Epub 2022 May 26.

Wuhan University, College of Chemistry and Molecular Sciences, 299 Bayi Road, Wuchang, Wuhan, Hubei, China, 430072, 430072, Wuhan, CHINA.

1,3- trans -Disubstituted tetrahydroisoquinoline (THIQ) is a common heterocyclic structural unit of naphthylisoquinoline alkaloids. The assembly of this structural unit is not trivial, which constitutes a substantial challenge in the total synthesis of naphthylisoquinoline alkaloids and related pharmaceuticals. Herein, we report a modular and convergent method for the rapid assembly of 1,3- trans -disubstituted THIQ frameworks through a three-component Catellani reaction and a Au(I)-catalyzed cyclization/reduction cascade. Read More

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Robert Tuba.

Authors:

Angew Chem Int Ed Engl 2022 May 26:e202206450. Epub 2022 May 26.

"The most important quality of a role model is humility … My favorite science outreach activity is inviting young students to our labs and showing them how beautiful the chemistry is …" Find out more about Robert Tuba in his Introducing … Profile. Read More

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Synthesis of Si-Stereogenic Silanols by Catalytic Asymmetric Hydrolytic Oxidation.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

Southern University of Science and Technology, Chemistry, No 1088,xueyuan Rd., Xili, Nanshan District, 518055, Shenzhen, CHINA.

Despite a growing progress for the construction of chiral organosilicon compounds, the catalytic asymmetric synthesis of silicon-stereogenic silanols is less explored and remains a considerable challenge. Herein, we report the first enantioselective construction of silicon-stereogenic silanols via catalytic asymmetric hydrolytic oxidation of dihydrosilanes. This practical protocol features ambient reaction conditions, high atom economy, good functional-group compatibility, and cleaner manner with H2 as the only by-product, producing a wide range of valuable chiral silanols and bis-silanols in decent yields with excellent chemo- and stereoselectivity. Read More

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Catalytic Atroposelective Electrophilic Amination of Indoles.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

Huazhong University of Science and Technology, School of Chemistry and Chemical Engineering, Luoyu road 1037, 430074, Wuhan, CHINA.

Reported here is the first catalytic atroposelective electrophilic amination of indoles, which delivers functionalized atropochiral N-sulfonyl-3-arylaminoindoles with excellent optical purity. This reaction was furnished by 1,6-nucleophilic addition to p -quinone diimines. Control experiments suggest an ionic mechanism that differs from the radical addition pathway commonly proposed for 1,6-addition to quinones. Read More

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Access to Unexplored 3D Chemical Space: cis-Selective Arene Hydrogenation for the Synthesis of Saturated Cyclic Boronic Acids.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

Westfälische Wilhelms-Universität Münster: Westfalische Wilhelms-Universitat Munster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149, Münster, GERMANY.

A new class of saturated boron-incorporated cyclic molecules has been synthesized employing an arene-hydrogenation methodology. cis -Selective hydrogenation of easily accessible, and biologically important molecules comprising benzoxaborole, benzoxaborinin, and benzoxaboripin-derivatives is reported. Among the various catalysts tested, rhodium cyclic(alkyl)(amino)carbene [Rh-CAAC] ( 1 ) pre-catalyst revealed the best hydrogenation activity confirming turnover number up to 1400 with good to high diastereoselectivity. Read More

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Small Molecule Inhibitors of Interferon-Induced JAK-STAT Signalling.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

Institut Curie Research Center, Organic Synthesis and Cell Biology Group, 26 rue d'Ulm, 75248, Paris, FRANCE.

Interferons (IFN) are cytokines which, upon binding to cell surface receptors, trigger a series of downstream biochemical events including Janus Kinase (JAK) activation, phosphorylation of Signal Transducer and Activator of Transcription protein (STAT), translocation of pSTAT to the nucleus and transcriptional activation. Dysregulated IFN signalling has been linked to cancer progression and auto-immune diseases. Here, we report the serendipitous discovery of a small molecule that blocks IFNγ activation of JAK-STAT signalling. Read More

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The chemistry of Cu3N and Cu3PdN nanocrystals.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

University of Basel: Universitat Basel, Chemistry, Mattenstrasse 24a, BioPark Rosenthal 1096, 4058, Basel, SWITZERLAND.

The precursor conversion chemistry and surface chemistry of Cu 3 N and Cu 3 PdN nanocrystals are unknown or contested. Here, we first obtain phase pure, colloidally stable nanocubes. Second, we elucidate the pathway by which copper(II) nitrate and oleylamine form Cu 3 N. Read More

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Enhanced Photocatalytic CO2 Reduction through Hydrophobic Microenvironment and Binuclear Cobalt Synergistic Effect in Metallogels.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

University of Science and Technology Beijing, Department of Chemistry, 30 Xueyuan Road, Haidian District, 100083, Beijing, CHINA.

Assemblies that mimic natural lipid bilayers are theoretically efficient for photocatalytic CO2 reduction; however, such an approach has not been yet explored. Herein, metallogels (LG/Nico-Co) based on the co-assembly of L-glutamic acid lipid (LG/Nico) and cobalt (Co) ions exhibited excellent photocatalytic CO2 reduction, with 208724 μmol g-1 CO production within 24 h and 90% CO/H2 selectivity, or 166826 μmol g-1 CO production within 12 h and 46% CO/H2 selectivity, depending on the water content of the solvent. The alkyl chains of LG/Nico provide a hydrophobic microenvironment for efficient gas transfer, and the assembled bilayers induce a synergistic effect between two adjacent Co ions for catalyzing the CO2 reduction reaction. Read More

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An endo-Directing-Group Strategy Unlocks Enantioselective (3+1+2) Carbonylative Cycloadditions of Aminocyclopropanes.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

University of Liverpool, School of Chemistry, L69 3BX, Liverpool, UNITED KINGDOM.

An endo-directing group strategy enables enantioselective (3+1+2) cycloadditions that are triggered by carbonylative C-C bond activation of cyclopropanes. These processes are rare examples of cycloadditions where C-C bond oxidative addition is enantiodetermining, and the first where this is achieved within the context of a multicomponent (higher order) reaction design. Read More

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Li-N Interaction Induced Deep Eutectic Gel Polymer Electrolyte for High Performance Lithium-Metal Batteries.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

Peking University, School of Material Science and Engineering, 5 Yiheyuan Road, 100871, Beijing, CHINA.

As emerging eutectic mixtures, deep eutectic electrolytes (DEEs) show unique properties for Li metal batteries (LMBs). However, the limited choice and inferior electrode compatibility hinder their further development in LMBs. Herein, we report a new 1,2-dimethylimidazole (DMIm)-based deep eutectic gel polymer electrolyte induced by Li-N interaction . Read More

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Polarization-Dependent Ultrasensitive Dynamic Wrinkling on Floating Films Induced by Photo-Orientation of Azopolymer.

Angew Chem Int Ed Engl 2022 May 25. Epub 2022 May 25.

Tianjin University, Nankai District, Weijin Road No.92, 300384, Tianjin, CHINA.

Ubiquitous surface wrinkling has been well studied theoretically and experimentally. How to modulate the stress state of a liquid-supported system for the unexploited wrinkling capabilities remains a challenge. Here we report a simple linearly-polarized-light illumination to spatiotemporally trigger ultrasensitive in-situ dynamic wrinkling on a floating azo-film. Read More

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VPO4F Fluorophosphates Polyanion Cathodes for High-Voltage Proton Storage.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

Fudan University, Department of Chemistry, CHINA.

Proton batteries are emerging in electrochemical energy storage for the fast kinetics, low cost and high safety. However, their development is hindered by the relatively low energy density due to the limited choice of cathode materials. Herein, metal phosphates polyanion cathodes were proposed as the proton cathode for the first time. Read More

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Eutectic Electrolyte with Unique Solvation Structure for High-Performance Zinc-Ion Batteries.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

Wuhan University of Technology, 122 Luoshi Road, 430070, Wuhan, CHINA.

Zinc-ion battery (ZIB) presents great potential in energy storage due to low cost and high safety. However, the poor stability, dendrite growth, and narrow electrochemical window limit its practical application. Herein, we develop a new eutectic electrolyte consisting of ethylene glycol (EG) and ZnCl 2 for dendrite-free and long-lifespan ZIBs. Read More

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Nickel-Catalyzed Switchable Site-Selective Alkene Hydroalkylation by Temperature Regulation.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

University of Science and Technology of China, Chemistry, Jinzhai Road, 230026, Hefei, CHINA.

Regiodivergent alkene functionalization that produces either regioisomer starting from the same raw materials is desirable. Herein, we report a nickel-catalyzed switchable site-selective alkene hydroalkylation. The selection of reaction temperatures leads to protocols that provide regiodivergent hydroalkylated products starting from a single alkene substrate. Read More

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Oxidation Potential Gap (ΔEox): The Hidden Parameter in Redox Chemistry.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

Tokyo University of Agriculture and Technology: Tokyo Noko Daigaku, Applied Biological Science, 3-5-8 Saiwai-cho, Fuchu, 183-8509, Tokyo, JAPAN.

Oxidative biaryl coupling of aryls with different electronic features generally fails. However, this has not been systematically studied via theoretical analysis, and thus, the crucial factor governing coupling efficiency remains unclear. Herein, we propose that the "oxidation potential gap ( Δ E ox )" is a key parameter in predicting the efficiency of an intramolecular oxidative coupling reaction, with Δ E ox defined as a difference in the oxidation potentials of the relevant aromatic rings. Read More

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Dissecting Solvent Effects on Hydrogen Bonding.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

University of Edinburgh, EaStCHEM School of Chemistry, Joseph Black Building, David Brewster Road, EH9 3FJ, Edinburgh, UNITED KINGDOM.

The experimental isolation of H-bond energetics from the typically dominant influence of the solvent remains challenging. Here we use synthetic molecular balances to quantify amine/amide H-bonds in competitive solvents. Over 200 conformational free energy differences were determined using 24 H-bonding balances in 9 solvents spanning a wide polarity range. Read More

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Doping-Mediated Energy-Level Engineering of [email protected] Superatoms (M = Pd, Pt, Rh, Ir) for Efficient Photoluminescence and Photocatalysis.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

The University of Tokyo, Department of Chemistry, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, JAPAN.

We synthesized a series of MAu 12 (dppe) 5 Cl 2 ( MAu 12 ; M = Au, Pd, Pt, Rh, or Ir; dppe = 1,2-bis(diphenylphosphino)ethane), which have icosahedral [email protected] 12 superatomic cores, and systematically investigated their electronic structures, photoluminescence (PL) and photocatalytic properties. The energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) was expanded when doping an M element positioned at the lower left of the periodic table. The PL quantum yield was enhanced with an increase in the HOMO-LUMO gap and reached to 0. Read More

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Total Synthesis of (-)-Bastimolide A: A Showcase for Type I Anion Relay Chemistry.

Angew Chem Int Ed Engl 2022 May 24:e202204884. Epub 2022 May 24.

Department of Chemistry, University of Pennsylvania, 231 S. 34th street, Philadelphia, PA 19104, USA.

A highly convergent total synthesis of (-)-bastimolide A (1), a polyhydroxy antimalarial macrolide, has been achieved via a longest linear sequence of twenty steps from commercially available glycidyl ethers. Type I Anion Relay Chemistry (ARC) coupling tactics enable rapid construction of the molecule's 1,5-polylol backbone. A late-stage B-alkyl Suzuki-Miyaura union and an Evans-modified Mukaiyama macrolactonization generate the forty-membered Z-α,β-unsaturated macrocyclic lactone. Read More

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Ligand-Controlled NiH-Catalyzed Regiodivergent Chain-Walking Hydroalkylation of Alkenes.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

Tianjin Normal University, College of Chemistry, 393 Binshui West Raod, Xiqing District, 300387, Tianjin, CHINA.

A NiH-catalyzed migratory hydroalkylation of alkenyl amines with predictable and switchable regioselectivity is reported. By utilizing a ligand-controlled, directing group-assisted strategy, various alkyl units are site-selectively installed at inert sp 3 C - H sites far away from the original C=C bonds. A range of structurally diverse α- and b -branched protected amines are conveniently synthesized via stabilization of 5 and 6-membered nickelacycles respectively. Read More

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A Photoswitchable Ligand Targeting the β1-Adrenoceptor Enables Light-Control of the Cardiac Rhythm.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

Institute of Advanced Chemistry of Catalonia: Institut de Quimica Avancada de Catalunya, Chemical Biology, Jordi Girona, 20, 08034, Barcelona, SPAIN.

Catecholamine-triggered β-adrenoceptor (β-AR) signaling is essential for the correct functioning of the heart. Although both β1- and β2-AR subtypes are expressed in cardiomyocytes, drugs selectively targeting β1-AR have proven this receptor as the main target for the therapeutic effects of beta blockers in the heart. Here, we report a new strategy for the light-control of β1-AR activation by means of photoswitchable drugs with a high level of β1-/β2-AR selectivity. Read More

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Electrolyte Sieving Chemistry in Suppressing Gas Evolution of Sodium Metal Batteries.

Angew Chem Int Ed Engl 2022 May 24. Epub 2022 May 24.

Nanjing University, Xianlin 168, Nanjing, CHINA.

The sodium (Na) metal batteries hold great promise as a sustainable technology owing to the high element abundance and low cost. However, the generally used carbonate electrolytes remain highly reactive towards Na metal, leaving flammable gas evolution. Here, we propose an electrolyte sieving strategy to separate anion-mediated ion-pairs from dilute electrolytes by introducing a 3A zeolite molecular sieve film. Read More

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