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Stereoselective Intermolecular [2+2] Cycloadditions of Erlenmeyer-Pl?chl Azlactones using Visible Light Photoredox Catalysis
摘要： The first report of the preparation of symmetric and non-symmetric diaminotruxinic derivatives through the photoredox [2+2] cycloadditions of Erlenmeyer azlactones is described, affording the desired compounds in high regio- and diastereocontrol (only head-to-head coupling). Mechanistic studies by DFT suggest that the reaction proceeds through a neutral photocatalytic pathway.
关键词： photoredox catalysis,diaminotruxinic derivatives,[2+2] cycloaddition,Erlenmeyer azlactones,DFT studies
更新于2025-09-09 09:28:46
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Exploration of highly efficient blue-violet light conversion agents for agricultural film based on structure optimization of TPA
摘要： To obtain highly efficient blue-violet light conversion agents used for agricultural film, six triarylacrylonitrile derivatives and their doping films were prepared. Further, the luminogens have the ability to convert UV light into blue-violet light, and exhibit aggregation dependent fluorescence emission and high-contrast fluorescence quantum yields from 0.004 to 0.833. Based on X-ray single crystal diffraction analysis and aggregation-induced emission activity tests, the variant fluorescence quantum yields are attributed to intermolecular π-π stacking and phase transition between crystalline state and amorphous state. In simulated greenhouse environment, the luminogens exhibit excellent photostability. However, their fluorescence intensity drop to 17%-40% of prime intensity after outdoor radiation for one month due to the ring-closing oxidation reaction (In summer). By comprehensively considering the above photophysical properties and mechanical properties of the doping film, Ph4TPA is a potential light conversion agent for agricultural film in winter. More importantly, the results indicate the properties of the light conversion films are expected to be further improved by molecular design inhibiting the ring-closing oxidation reaction and dispersion of crystalline nanoparticles in the doping film.
关键词： Light conversion film,Light conversion agents,Fluorescence,Photosynthesis,Acrylonitrile derivatives
更新于2025-09-09 09:28:46
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Tripyridine-Derivatives-Derived Semiconducting Iodo-argentate/cuprate Hybrids with Excellent Visible-light Induced Photocatalytic Performance
摘要： Through regulating the pH values, a series of iodo-argentate/cuprate hybrids, [Me3(4-TPT)]4[Ag6I18] (1, Me3(4-TPT) = N,N’,N’’-trimethyl-2,4,6-tris(4-pyridyl)-1,3,5-triazine), [Me3(4-TPT)][M5I8] (M=Ag/2, Cu/2a), [Me3(3-TPT)][M5I8] (Me3(3-TPT) = N,N’,N’’-trimethyl-2,4,6-tris(3-pyridyl)-1,3,5-triazine, M=Ag/3, Cu/4), exhibit adjustable structural variations with different dimensional structures, have been obtained under solvothermal conditions. They are directed by two types of in situ N-alkylation TPT-derivatives (Me3(4-TPT) for 1/2/2a and Me3(3-TPT) for 3/4) and represent the isolated units (1), 1-D polymeric chain (4), 2-D layered structures (2/2a, 3) based on diverse metal iodide clusters. These compounds possess reducing band gaps comparing with the bulk β-AgI and CuI and belong to potential semiconductor materials. Iodocuprates feature highly efficient photocatalytic activity in sunlight-induced degradation of organic dyes. The detailed study on the possible photocatalytic mechanism, including the radical trapping tests and theoretical calculations, reveals that the N-alkylation TPT moieties contribute to the narrow semiconducting behavior and effectively inhibit the recombination of photogenerated electron–hole pairs, which result in an excellent visible-light induced photocatalytic performance.
关键词： visible-light-driven,photocatalysis,structural variations,inorganic–organic hybrid metal halides,polypyridine-derivatives
更新于2025-09-09 09:28:46
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Photoluminescent properties in perylene PVD films: Influence of molecular aggregates and supramolecular arrangement
摘要： Organic thin films are at the forefront of basic studies and applications in the field of physics, chemistry, biochemistry and materials science. For example, the intrinsic supramolecular arrangement, or simply the formation of aggregates may alter the optical and electrical properties, which would impact the potential applications of the material. Here, an attempt is made to correlate the molecular structures of two perylene derivatives, bis butylimido perylene (BuPTCD) and bis phenethylimido perylene (PhPTCD), with their film formation, in particular, the supramolecular arrangement and the photoluminescent properties. Emission spectra show that the PhPTCD has a radiative efficiency (RE) higher than that for BuPTCD when both are in solutions (monomers). Complementary, regarding PVD films, UV-Vis absorption measurements reveal that PhPTCD forms, predominantly, J aggregates, which are responsible for perylene derivative emission. However, BuPTCD PVD films are found to provide higher RE than PhPTCD PVD film. This apparent controversy could be explained considering other features such as crystallinity and molecular organization. The PVD film of BuPTCD is crystalline while PhPTCD PVD film is amorphous; BuPTCD has an edge-on while PhPTCD has a face-on molecular organization in PVD films.
关键词： perylene derivatives,PVD thin films,aggregates,photoluminescent properties,supramolecular arrangement
更新于2025-09-09 09:28:46
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Disubstituted Aminoanthraquinone-Based Photoinitiators for Free Radical Polymerization and Fast 3D Printing under Visible Light
摘要： The development of highly efficient and rapid photoinitiating systems for free radical photopolymerization under the irradiation of visible light has attracted increasing attention due to their widespread potential applications in, for example, 3D printing or dental polymers. Unfortunately, currently available visible-light-sensitive photoinitiators are not efficient enough for 3D printing applications suffering from low printing speeds. Here we describe a series of photoinitiating systems consisting of disubstituted amino-anthraquinone derivatives (i.e., 1-amino-4-hydroxy-anthraquinone, 1,4-diaminoanthraquinone, and 1,5-diamino-anthraquinone) and various additives (e.g., tertiary amine and phenacyl bromide) toward the free radical photopolymerization of various acrylate monomers (such as commercial 3D resin) under the irradiation of blue to red LEDs. It is shown that the type and position of substituents of the aminoanthraquinone derivative can significantly affect its photoinitiation properties. The most efficient disubstituted aminoanthraquinone derivative-based photoinitiating system was selected and used for the 3D printing of a commercial 3D resin in a 3D printer with polychromatic visible light as the irradiation source. It is shown that its printing speed was dramatically enhanced compared to a commercial photoinitiator 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO).
关键词： aminoanthraquinone derivatives,free radical photopolymerization,photoinitiating systems,visible light,3D printing
更新于2025-09-09 09:28:46
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Construction of a Layered Hydrogen-Bonded Organic Framework Showing High-Contrast Mechanoresponsive Luminescence Turn-On
摘要： This paper probes the mechanoresponsive luminescence and aggregation-induced emission (AIE) properties of N-phenylcarbazole-based thiophene/dicyanovinyl (T?DCV) derivatives. In bis-T?DCV planar molecule 1, a layered hydrogen-bonded organic framework (HOF) structure is formed with the assistance of multiple C?H···N and strong interlayer interactions. The formation of such a layer packing HOF structure can quench the solid fluorescent emission when aggregated as nanosuspensions but guarantees the high-contrast luminescence on?off switching (1.2 × 103 fold) in the solid state. Moreover, the grinding-induced destruction of HOF 1 is reflected by powder X-ray diffraction measurements, in which the destruction of the α and β rings in the planar HOF stripe and the close interlayer stacking could be observed. This work achieves the successful construction of long-wavelength emission AIE molecules (2 and 3) by introducing sufficient steric hindrance rotors to disturb the intermolecular π?π stacking and/or dipole?dipole interactions.
关键词： high-contrast luminescence,aggregation-induced emission,mechanoresponsive luminescence,hydrogen-bonded organic framework,thiophene/dicyanovinyl derivatives
更新于2025-09-04 15:30:14
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From graphyne to cata-condensed (Acenographynes) and peri-condensed PAHs-graphyne derivatives
摘要： The standard enthalpy of formation DHf(cid:1) and the free energy of formation DGf(cid:1) were calculated using group increment approach on graphyne (called benzographyne in this work) and on graph-diyne (benzographdiyne) and higher homologues. The DHf(cid:1) and DGf(cid:1) values were compared with those reported in literature and obtained by quantum chemical calculations and found in good agreement. Furthermore, the DHf(cid:1) and DGf(cid:1) were calculated also on two new families of graphyne derivatives called respectively acenographynes and peri-condensed PAHs-graphyne derivatives obtained by substituting the benzenoid ring in a graphyne sheet with larger PAHs taken from the acene and from the peri-condensed PAHs series. Larger PAHs cores inserted in the graphyne sheet and connected with short acetylene bridges are characterized by the lowest DHf(cid:1) and DGf(cid:1) even lower than those of benzographyne and C60 and C70 fullerenes, suggesting that peri-condensed PAHs-graphyne derivatives could be experimentally accessible.
关键词： benzographyne,peri-condensed PAHs-graphyne derivatives,acenographynes,Graphyne
更新于2025-09-04 15:30:14
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Alkyl chain-dependent cyano-stilbene derivative's molecular stacking, emission enhancement and fluorescent response to the mechanical force and thermal stimulus
摘要： Two cyano-stilbene derivatives with butyl (C4MPA) and octyl groups (C8MPA) were synthesized to investigate the effects of alkyl chains on molecular stacking, emission enhancement, and mechanofluorochromism. The two compounds displayed weak emissions in monomolecular state and emitted an enhanced fluorescence in crystal state. However, the fluorescence quantum yield of C4MPA (19%) was lower than that of C8MPA (76%). Face-to-face dimer stacking was found only in the C4MPA crystal, in which molecules adopted a nonplanar configuration. The C8MPA crystal presented two kinds of antiparallel 1D arrangement. One involved the antiparallel stacking of nonplanar aromatic moieties. The other consisted of coplanar molecules without π-π stacking, which were responsible for the higher luminescence yield. Moreover, the emission of the C4MPA solid was quenched under mechanical force, whereas the C8MPA solid still emitted a strong fluorescence after grinding. C8MPA lost fluorescence when heated at above 60 °C because of its low melting point, and the supercooling viscous liquid without fluorescence was observed even the sample was cooled to room temperature for 10 h, meaning a very slowly crystallization process. Such non-emissive supercooling viscous liquid might rapidly transform into strongly emissive solid under the mechanical force shearing stimulus. Thus, C8MPA films could be used as sensors for mechanical force and thermal stimuli.
关键词： mechanofluorochromism,emission enhancement,molecular stacking,thermal stimulus,cyano-stilbene derivatives,alkyl chains
更新于2025-09-04 15:30:14
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Carbon Nitride Dots: A Selective Bioimaging Nanomaterial
摘要： In contrast to the recent immense attention in carbon nitride quantum dots (CNQDs) as a heteroatom-doped carbon quantum dot (CQD), their biomedical applications have not thoroughly investigated. The targeted cancer therapy is a prominently researched area in biomedical field. Here, the ability of CNQDs as a selective bioimaging nanomaterial was investigated to assist the targeted cancer therapy. CNQDs were first synthesized using four different precursor sets, involving urea derivatives and the characteristics were compared to select the best candid material for bioapplications. Characterization techniques such as UV-vis, luminescence X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy and transmission electron microscopy were used. These CNQDs were analyzed in in vitro studies of bioimaging and labeling using pediatric glioma cells (SJGBM2) for possible selective biolabeling and nano-distribution inside the cell membrane. The in vitro cellular studies were conducted under long-wavelength emission without the interference of blue autofluorescence. Thus, excitation-dependent emission of CNQDs was proved to be advantageous. Importantly, CNQDs selectively entered SJGBM2 tumor cells while it did not disperse in to normal human embryonic kidney cells (HEK293). The distribution studies in the cell cytoplasm indicated that CNQDs disperse into lysosomes within approximately 6 h after the incubation. The CNQDs exhibited great potential as a possible nanomaterial in selective bioimaging and drug-delivery for targeted cancer therapy.
关键词： Pediatric glioma cells,Long-wavelength emission,Urea derivatives,Carbon nitride Quantum dots,Fluorescence,Selective bioimaging
更新于2025-09-04 15:30:14
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Fluorescence Behavior of Bis(cyanostyryl)pyrrole Derivatives Depending on Substituent Position of Cyano Groups in Solution and in Solid State
摘要： We synthesized a novel fluorophores of distyrylpyrrole derivatives possessing cyano groups at different position on olefin. Their fluorescence properties in solution and solid state were investigated by photoluminescence quantum yield and lifetime measurement, which provided radiative decay constant (kf) and nonradiative decay constant (knr). The derivative with cyano groups at inner position of molecule, inner isomer, shows high fluorescence quantum yield (Φf = 0.43) in solution while another derivative with cyano group at outer position, outer isomer, hardly shows fluorescence (Φf < 0.01) due to the large nonradiative decay (knr > 10 ns?1). Upon formation of single crystal or nanoparticles, these difference were inverted; the quantum yield of outer and inner isomer was enhanced and diminished, respectively. We explained these differences between in solution and solid state by means of analysis of single X-ray structure and computation study.
关键词： solid emission,pyrrole derivatives,substituent effect,Solid-state luminescence enhancement
更新于2025-09-04 15:30:14