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oe1(光电查) - 科学论文

8 条数据
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  • Synthesis of cyclo-PLAI using a combination of solid- and solution-phase methods

    摘要： Cyclo-PLAI was successfully synthesized using a combination of solid- and solution-phase methods. This current synthesis was found to be faster than the previously reported synthesis for the cyclic peptide. The linear precursor was synthesized on 2-chlorotrityl resin with Fmoc/t-Bu strategy. HATU/HOAt was employed as the coupling reagent in the amide bond formation on the resin. Cyclization of the linear precursor was experimented with HATU/HOAt reagents with different conditions. However, the linear precursor was best cyclized using HATU reagent in DIPEA by stirring the reaction mixture at 0 °C for 1 h and followed by stirring the reaction mixture at room temperature for 30 min, giving the cyclic product in 70% yield (calculated from the linear peptide). Both linear and cyclic products were characterized using HR-TOF-ESMS, 1H-NMR, 13C-NMR, and compared with previously reported spectral data for the cyclic product.

    关键词： 2-chlorotrityl resin,Cyclo-PLAI,cyclotetrapeptide,HATU cyclization,solid-phase peptide synthesis

    更新于2025-09-23 15:23:52

  • Planar Antiaromatic Core-Modified 24π Hexaphyrin(1.0.1.0.1.0) and 32π Octaphyrin(1.0.1.0.1.0.1.0) Bearing Alternate Hybrid-Diheterole Units

    摘要： Lewis acid catalyzed self-condensation of hybrid diheterole (furan-pyrrole and thiophene-pyrrole) precursors afforded novel Hückel antiaromatic 24π hexaphyrin(1.0.1.0.1.0) and 32π octaphyrin(1.0.1.0.1.0.1.0) without β-annulated bridges. Single-crystal X-ray diffraction analysis of the hybrid porphyrinoids (S3N3-ox and O4N4-ox) revealed nearly planar conformation and the 1H NMR spectra suggested the presence of paratropic ring currents. These antiaromatic macrocycles showed the characteristic optical features and undergo reversible two-electron reduction to Hückel aromatic 26π- and 34π-electron species, respectively, as is evident from the spectroscopic and theoretical studies (NICS and ACID calculations). Implementation of hybrid diheteroles alternately into the expanded porphyrin skeletons would be a novel approach for fine-tuning of the electronic structures of the planar antiaromatic macrocycles.

    关键词： cyclization,antiaromaticity,conformation,redox,porphyrinoids

    更新于2025-09-23 15:22:29

  • Chiral Carbazoles

    摘要： Asymmetric Synthesis of Axially Chiral Benzocarbazole Derivatives Based on Catalytic Enantioselective Hydroarylation of Alkynes

    关键词： cyclization,axial chirality,benzocarbazoles

    更新于2025-09-23 15:21:21

  • Five Points for Graphene Nanobowls!

    摘要： Given the difficulty of studying the chemical properties of graphene directly, many researchers have turned to the use of small molecules as model systems. In this report, the authors demonstrate the synthesis of a model system for porous nanographenes. Anion binding, electronic properties, and aggregation are probed in the final product.

    关键词： Scholl cyclization,polycyclic aromatic hydrocarbons,nanographenes

    更新于2025-09-23 15:21:21

  • A highly selective “turn-on” fluorescent probe for detecting Cu2+ in two different sensing mechanisms

    摘要： A new coumarin-derived hydrazone (1) has been developed as a “turn-on” fluorescent probe for the detection of Cu2+ in two different sensing mechanisms. In anhydrous acetonitrile, the strong fluorescence response of 1 to Cu2+ was mainly attributed to the chelation-controlled C=N isomerisation. Besides, S-donor is indispensable in protecting from the Cu2+-induced fluorescence quenching. In aqueous acetonitrile, 1 as a chemodosimeter can highly selectively sense of Cu2+, which was ascribed to the Cu2+-promoted cyclization reaction affording the strong fluorescent cyclization product (2). The proposed cyclization reaction was confirmed by the single-crystal structure of 2. Furthermore, 1 was utilized for imaging intracellular Cu2+ with good performance.

    关键词： Live cell imaging,Fluorescent probe,Copper ion,Coumarin,Cyclization

    更新于2025-09-23 15:19:57

  • Efficient ambient-air-stable HTM-free carbon-based perovskite solar cells with hybrid 2D–3D lead halide photoabsorbers

    摘要： The title reaction has been established, which offers a useful method for the construction of dihydrocoumarin frameworks in generally good chemical yields (up to 99%) and high diastereoselectivities (up to >95 : 5 dr). This reaction represents a good example of [4 + 2] cyclizations of para-quinone methide derivatives with electron-rich reaction partners under catalyst-free conditions.

    关键词： [4 + 2] cyclization,dihydrocoumarin frameworks,Catalyst-free,para-quinone methide derivatives,homophthalic anhydrides

    更新于2025-09-11 14:15:04

  • 23.5: Improvement of Ambient Contrast of Micro‐LED Devices with High Reliability

    摘要： Rhodium (Rh)-catalysed [4 + 2] annulation of aromatic oximes with common terminal alkenes for the synthesis of 3,4-dihydroisoquinolines is presented. Through the cooperation of a Rh (III) catalyst and a catalytic amount of K2HPO4 base, the reaction enables the formation of two new bonds, a C(sp2)(cid:0) C(sp3) bond and a C(sp3)(cid:0) N bond, in a single reaction via functionalization of both the C(cid:0) H and N(cid:0) O bonds and provides a practical method to produce 3,4-dihydroisoquinolines with exquisite selectivity and excellent compatibility of functional groups.

    关键词： oximes,dihydroisoquinolines,cyclization,rhodium,annulation,alkenes

    更新于2025-09-11 14:15:04

  • Visual colorimetric and fluorescence turn-on probe for Cu(II) ion based on coordination and catalyzed oxidative cyclization of ortho amino azobenzene

    摘要： 2,2′-diaminoazobenzene (L1), a visual colorimetric and fluorescence turn-on detection probe for Cu2+ ion, has been discovered successfully. The yellow L1 solution changed into light-purple solution rapidly with dropping of Cu2+ ion observed by the naked eyes, for the formation of 1:1 complex of L1 and Cu2+ ion calculated by Job-plot method. Non-emissive L1 transformed into 2-(2-aminophenyl) benzotriazole (L1-BTA) with strong fluorescence at the peak around 475 nm, owing to the Cu2+ catalyzed oxidative cyclization of L1, accompanied by the fluorescence intensity gradually increasing within 20 min. And L1 was applied for quantitative detection of Cu2+ with good linear relationship between its UV absorbance and Cu2+ concentration, and exhibited high fluorescence selectivity toward Cu2+ over other metal ions (Fe3+, Zn2+, Cd2+, Co2+, Ni2+, Mn2+, Na+, Al3+ and Ca2+) in EtOH solution.

    关键词： Cu(II) ion,Oxidative cyclization,Fluorescence probe,Coordination,Amino azobenzene

    更新于2025-09-04 15:30:14