- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Rapid syntheses of (?)-FR901483 and (+)-TAN1251C enabled by complexity-generating photocatalytic olefin hydroaminoalkylation
摘要： We report a common strategy to facilitate the syntheses of the polycyclic alkaloids (?)-FR901483 (1) and (+)-TAN1251C (2). A divergent synthetic strategy provides access both natural products through a pivotal spirolactam intermediate (3), which can be accessed on a gram-scale. A photocatalytic olefin hydroaminoalkylation brings together three readily available building blocks and forges the majority of the carbon framework present in 1 and 2 in a single operation, leading to concise total syntheses. The complexity-generating photocatalytic process also provides direct access to novel non-racemic spirolactam scaffolds that are likely to be of interest to early-stage drug discovery programs.
关键词： medicinal chemistry,natural product synthesis,amine synthesis,photoredox chemistry,radical chemistry
更新于2025-09-12 10:27:22
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Metal-free and photo-controlled fabrication of fluorinated anti-fouling film
摘要： We reported a new photo-controlled synthesis route to fabricate a fluorine-containing thin film for protecting the oxidation of indium tin oxide (ITO) and other derivatives such as the fluorine-doped tin oxide (FTO) coated glasses. A relatively inexpensive, color/metal-free organic phenothiazine-based photocatalyst for atom transfer radical polymerization (ATRP) was successfully adopted by an ultraviolet light source to modified substrates. The fluorine thin film had a contact angle (CA) with water of 105.1°, an advancing angle of 112.2°, and a receding angle of 84.6°; leading to a hydrophobic nature with self-cleaning and anti-fouling properties. Our fluorinated conductive glass shows an optical transmittance up to 80 – 90% in the visible wavelength range. This work demonstrates the great value in the anti-fouling of electronics that secures itself from chemical contaminations in outdoor environments and use at high temperature and chemical erosions.
关键词： Atom Transfer Radical Polymerization (ATRP),ITO,Photo-controlled,Polymer brushes,FTO
更新于2025-09-12 10:27:22
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Observation of vibronic emission spectrum of jet-cooled 4-chloro-m-xylyl radical
摘要： We report the vibronic emission spectrum of 4-chloro-m-xylyl radical using a long-path monochromator in a corona-excited supersonic expansion (CESE). By the precursor 4-chloro-m-xylene, we identi?ed 4-chloro-m-xylyl from the two isomeric benzyl-type radicals analyzing a Franck-Condon simulation and ab initio calculations. From an analysis of the vibronic emission spectrum of the 4-chloro-m-xylyl radical, the D1 → D0 electronic transition energy was con?rmed and the assignments of vibrational frequencies were accomplished in the ground state.
关键词： 4-chloro-m-xylyl radical,Corona discharge,Spectroscopy
更新于2025-09-12 10:27:22
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Determining a Line Strength in the ν <sub/>3</sub> Band of the Silyl Radical Using Quantum Cascade Laser Absorption Spectroscopy
摘要： Silane (SiH4) plasmas are widely used for the deposition of hydrogenated amorphous silicon (a-Si:H) films. Nevertheless, the chemical processes governing film deposition are still incompletely understood. Moreover, there is still no general method available to determine the absolute concentration of the silyl radical (SiH3), which is the accepted chemical precursor of a-Si:H films. In this study, a 10% silane in helium RF plasma was spectroscopically investigated between 2085 and 2175 cm?1 using an external cavity quantum cascade laser (EC-QCL) based spectrometer. This led to the identification of 4 distinct species from their absorption features: SiH4, disilane (Si2H6), SiH3, and an unassigned short-lived species. Furthermore, 17 absorption features of SiH3 were identified and unambiguously assigned. Fast spectral scanning of selected absorption features belonging to the four species in a 10 Hz pulsed RF plasma enabled the measurement and interpretation of their temporal behavior in terms of plausible chemical reactions involving silicon containing species. By quantitatively measuring the decay of the SiH3 a ← a pP4 (5) transition at 2151.3207 cm?1 after the discharge was stopped, its line strength (S) was determined to be (7.5 ± 5.5) × 10?20 cm2 cm?1 mol?1.
关键词： quantum cascade laser absorption spectroscopy,hydrogenated amorphous silicon,Silane plasmas,line strength,silyl radical
更新于2025-09-12 10:27:22
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Carbon Dots as Promising Green Photocatalyst for Free Radical and ATRP-Based Radical?Photopolymerization with Blue LEDs
摘要： This contribution reports for the first time about the use of carbon dots (CDs) as sensitizer to initiate and activate free radical and controlled radical polymerization based on an ATRP protocol with blue LEDs, respectively. Consideration of diverse heteroatom-doped CDs indicated well-functioning of N-doped CDs as effective photocatalyst and photosensitizer in combination with LEDs emitting either at 405 nm or 470 nm. Initiation of free radical polymerization occurred by combining the CDs with an iodonium or sulfonium salt in tri(propylene glycol) diacrylate. Polymerization of methyl methacrylate (MMA) by photo-induced ATRP was achieved with CDs and ethyl a-bromophenylacetate using Cu(II) as catalyst in the ppm range. The polymers obtained showed temporal control, narrower dispersity ?1.5, and chain-end fidelity. The first order obtained from kinetic slope and ON/OFF experiments additionally approved constant concentration of polymer radicals. No remarkable cytotoxic activity was observed of the CDs underlining their biocompatibility.
关键词： blue LED,free radical photopolymerization,photo-ATRP,cytotoxicity,Carbon dot
更新于2025-09-12 10:27:22
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A Facile Photocontrolled Iodine‐Mediated Reversible‐Deactivation Radical Polymerization System: Solution Polymerization of Methacrylates under Irradiation with NIR LED Light
摘要： Herein, near-infrared (NIR) photocontrolled iodine-mediated reversible-deactivation radical polymerization (RDRP) of various methacrylates without external photocatalyst was developed using alkyl iodide (e.g., 2-iodo-2-methylpropionitrile, CP-I) as the initiator at room temperature. We report the first example of using a series of special solvents containing carbonyl groups (e.g., 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), tetramethylurea (TMU), 1,3-dimethyl-tetrahydropyrimidin-2(1H)-one (DMPU), and N-methyl pyrrolidone (NMP)) as both solvent and catalyst for photocontrolled RDRP under irradiation with a long wavelength (λmax = 730 nm) light-emitting diode (LED) light. Therefore, the NIR photocontrolled polymerization system has the simplest components: monomer, alkyl iodide initiator and solvent. Well-defined polymers were synthesized with excellent control over the molecular weights and molecular weight distributions (Mw/Mn < 1.21). The “living” features of this promising NIR photocontrolled iodine-mediated RDRP system were confirmed by polymerization kinetics, multiple controlled “on-off” light switching cycle regulation, and chain extension experiments. Importantly, the radical polymerizations were also proceeded successfully with various thickness of skin of pork and A4 paper to demonstrate the unique advantages of this simplest polymerization system, which benefitting from the high penetration of NIR light.
关键词： radical polymerization,photopolymerization,alkyl iodide,NIR light,photocatalyst-free
更新于2025-09-12 10:27:22
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A Facile Photocontrolled Iodine-Mediated Reversible-Deactivation Radical Polymerization System: Solution Polymerization of Methacrylates under Irradiation with NIR LED Light
摘要： Herein, near-infrared (NIR) photocontrolled iodine-mediated reversible-deactivation radical polymerization (RDRP) of various methacrylates without external photocatalyst was developed using alkyl iodide (e.g., 2-iodo-2-methylpropionitrile, CP-I) as the initiator at room temperature. We report the first example of using a series of special solvents containing carbonyl groups (e.g., 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), tetramethylurea (TMU), 1,3-dimethyl-tetrahydropyrimidin-2(1H)-one (DMPU), and N-methyl pyrrolidone (NMP)) as both solvent and catalyst for photocontrolled RDRP under irradiation with a long wavelength (λmax = 730 nm) light-emitting diode (LED) light. Therefore, the NIR photocontrolled polymerization system has the simplest components: monomer, alkyl iodide initiator and solvent. Well-defined polymers were synthesized with excellent control over the molecular weights and molecular weight distributions (Mw/Mn < 1.21). The “living” features of this promising NIR photocontrolled iodine-mediated RDRP system were confirmed by polymerization kinetics, multiple controlled “on-off” light switching cycle regulation, and chain extension experiments. Importantly, the radical polymerization were also proceeded successfully with various thickness of skin of pork and A4 paper to demonstrate the unique advantages of this simplest polymerization system, which benefitting from the high penetration of NIR light.
关键词： radical polymerization,photopolymerization,alkyl iodide,NIR light,photocatalyst-free
更新于2025-09-12 10:27:22
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Enhanced triplet state generation through radical pair intermediates in BODIPY-quantum dot complexes
摘要： Generation of triplet excited states through radical pair intermediates has been extensively studied in molecular complexes. Similar schemes remain rare in hybrid structures of quantum dot-organic molecules, despite intense recent interest of quantum dot sensitized triplet excited state generation. Herein, we demonstrate that the efficiency of the intersystem crossing from the singlet to the triplet state in boron dipyrromethene (BODIPY) can be enhanced in CdSe quantum dot-BODIPY complexes through a radical pair intermediate state consisting of an unpaired electron in the quantum dot conduction band and that in oxidized BODIPY. By transient absorption spectroscopy, we show that the excitation of BODIPY with 650 nm light leads to the formation of a charge separated state by electron transfer from BODIPY to CdSe (with a time constant of 6.33 ± 1.13 ns), competing with internal conversion to the ground state within BODIPY, and the radical pair state decays subsequently by back charge recombination to generate a triplet excited state (with a time constant of 158 ± 28 ns) or the ground state of BODIPY. The overall quantum efficiency of BODIPY triplet excited state generation was determined to be (27.2 ± 3.0)%. The findings of efficient triplet state formation and intermediate radical pair states in this hybrid system suggest that quantum dot-molecule complexes may be a promising platform for spintronics applications.
关键词： CdSe quantum dot,radical pair intermediates,transient absorption spectroscopy,intersystem crossing,spintronics,triplet excited states,BODIPY,quantum dot-organic molecules
更新于2025-09-12 10:27:22
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Carbon Dots as Promising Green Photocatalyst for Free Radical and ATRP‐Based Radical?Photopolymerization with Blue LEDs
摘要： This contribution reports for the first time about the use of carbon dots (CDs) as sensitizer to initiate and activate free radical and controlled radical polymerization based on an ATRP protocol with blue LEDs, respectively. Consideration of diverse heteroatom-doped CDs indicated well-functioning of N-doped CDs as effective photocatalyst and photosensitizer in combination with LEDs emitting either at 405 nm or 470 nm. Initiation of free radical polymerization occurred by combining the CDs with an iodonium or sulfonium salt in tri(propylene glycol) diacrylate. Polymerization of methyl methacrylate (MMA) by photo-induced ATRP was achieved with CDs and ethyl a-bromophenylacetate using Cu(II) as catalyst in the ppm range. The polymers obtained showed temporal control, narrower dispersity ?1.5, and chain-end fidelity. The first order obtained from kinetic slope and ON/OFF experiments additionally approved constant concentration of polymer radicals. No remarkable cytotoxic activity was observed of the CDs underlining their biocompatibility.
关键词： blue LED,free radical photopolymerization,photo-ATRP,cytotoxicity,Carbon dot
更新于2025-09-12 10:27:22
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Beyond DPPH: Use of Fluorescence-Enabled Inhibited Autoxidation to Predict Oxidative Cell Death Rescue
摘要： Shah et al. develop a fluorescence-enabled inhibited autoxidation (FENIX) approach that permits accurate quantitation of radical-trapping antioxidant activity in phospholipid bilayers. The methodology is far superior to existing assays (e.g., DPPH) and enables reliable prediction of the anti-ferroptotic potency of redox-active compounds. The approach is easily amenable to high-throughput screening.
关键词： anti-ferroptotic potency,high-throughput screening,radical-trapping antioxidant activity,DPPH assay,phospholipid bilayers,FENIX
更新于2025-09-12 10:27:22