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A self-assembly/disassembly two-photo ratiometric fluorogenic probe for bacteria imaging
摘要： A fluorogenic probe for bacteria imaging was reported. The binding with anionic bacterial surfaces disassembled the self-assembly probe to turn-on the fluorescence and shift pyrene monomer/excimer ratiometric signals.
关键词： Self-assembly,Pyrene,Bacteria,Fluorogenic probe,Imidazolium
更新于2025-09-23 15:21:21
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Photocatalytic nucleophilic addition of alcohols to styrenes in Markovnikov and anti-Markovnikov orientation
摘要： The nucleophilic addition of methanol and other alcohols to 1,1-diphenylethylene (1) and styrene (6) into the Markovnikov- and anti-Markovnikov-type products was selectively achieved with 1-(N,N-dimethylamino)pyrene (Py) and 1,7-dicyanoperylene-3,4:9,10-tetracarboxylic acid bisimide (PDI) as photoredox catalysts. The regioselectivity was controlled by the photocatalyst. For the reductive mode towards the Markovnikov-type regioselectivity, Py was applied as photocatalyst and triethylamine as electron shuttle. This approach was also used for intramolecular additions. For the oxidative mode towards the anti-Markovnikov-type regioselectivety, PDI was applied together with Ph–SH as additive. Photocatalytic additions of a variety of alcohols gave the corres- ponding products in good to excellent yields. The proposed photocatalytic electron transfer mechanism was supported by detection of the PDI radical anion as key intermediate and by comparison of two intramolecular reactions with different electron density. Representative mesoflow reactor experiments allowed to significantly shorten the irradiation times and to use sunlight as “green” light source.
关键词： perylene bisimide,photochemistry,pyrene,photocatalysis,electron transfer
更新于2025-09-23 15:21:21
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Non-classically Controlled Sign in a 1.6 Tesla Magnetic Circularly Polarized Luminescence of Three Pyrenes in a Chloroform and a PMMA Film
摘要： Molecular pyrene, 1-hydroxylpyrene, and 2-hydroxypyrene in chloroform and embedded in poly(methyl methacrylate) film reveal mirror-image magnetic circularly polarized luminescence (MCPL) when south (S)-up or north (N)-up direction of the longitudinal external magnetic field of 1.6 T to unpolarized incident light (Faraday geometry) is employed. The |gMCPL| magnitude is on the order of 10–3 T–1 in 374–416 nm. The sign of MCPL is controlled by the S-up and N-up geometry and by the position (1- or 2-) of the hydroxy group.
关键词： magnetic circularly polarized luminescence,pyrene,chirality,fluorescence
更新于2025-09-23 15:21:01
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Development of a turn-on graphene quantum dot-based fluorescent probe for sensing of pyrene in water
摘要： Polycyclic aromatic hydrocarbons (PAHs) are potentially harmful pollutants that are emitted into the environment from a range of sources largely due to incomplete combustion. The potential toxicity and carcinogenic effects of these compounds warrants the development of rapid and cost-effective methods for their detection. This work reports on the synthesis and use of graphene quantum dots (GQDs) as rapid fluorescence sensors for detecting PAHs in water. The GQDs were prepared from two sources, i.e. graphene oxide (GO) and citric acid (CA) – denoted GO-GQDs and CA-GQDs, respectively. Structural and optical properties of the GQDs were studied using TEM, Raman, and fluorescence and UV-vis spectroscopy. The GQDs were then applied for detection of pyrene in environmental water samples based on a “turn-off-on” mechanism where ferric ions were used for turn-off and pyrene for turn-on of fluorescence emission. The fluorescence intensity of both GQDs was switched on linearly within the 2–10 × 10?6 mol L?1 range and the limits of detection were found to be 0.325 × 10?6 mol L?1 and 0.242 × 10?6 mol L?1 for GO-GQDs and CA-GQDs, respectively. Finally, the potential application of the sensor for environmental water samples was investigated using lake water and satisfactory recoveries (97–107%) were obtained. The promising results from this work demonstrate the feasibility of pursuing cheaper and greener environmental monitoring techniques.
关键词： Polycyclic aromatic hydrocarbons,Pyrene detection,Graphene quantum dots,Fluorescence sensors,Environmental water samples
更新于2025-09-23 15:21:01
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Suppressing the Photocatalytic Activity of Zinc Oxide Electron-Transport Layer in Nonfullerene Organic Solar Cells with a Pyrene-Bodipy Interlayer
摘要： Organic solar cells based on nonfullerene acceptors have recently witnessed a significant rise in their power conversion efficiency values. However, they still suffer from severe instability issues, especially in an inverted device architecture based on the zinc oxide bottom electron transport layers. In this work, we insert a pyrene-bodipy donor?acceptor dye as a thin interlayer at the photoactive layer/zinc oxide interface to suppress the degradation reaction of the nonfullerene acceptor caused by the photocatalytic activity of zinc oxide. In particular, the pyrene-bodipy-based interlayer inhibits the direct contact between the nonfullerene acceptor and zinc oxide hence preventing the decomposition of the former by zinc oxide under illumination with UV light. As a result, the device photostability was significantly improved. The π?π interaction between the nonfullerene acceptor and the bodipy part of the interlayer facilitates charge transfer from the nonfullerene acceptor toward pyrene, which is followed by intramolecular charge transfer to bodipy part and then to zinc oxide. The bodipy-pyrene modified zinc oxide also increased the degree of crystallization of the photoactive blend and the face-on stacking of the polymer donor molecules within the blend hence contributing to both enhanced charge transport and increased absorption of the incident light. Furthermore, it decreased the surface work function as well as surface energy of the zinc oxide film all impacting in improved power conversion efficiency values of the fabricated cells with champion devices reaching values up to 9.86 and 11.80% for the fullerene and nonfullerene-based devices, respectively.
关键词： bodipy,zinc oxide,photocatalytic activity,pyrene,organic solar cells,photostability,nonfullerene acceptors
更新于2025-09-23 15:21:01
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Photophysical properties and theoretical investigations of newly synthesized pyrene-naphthalene based Schiff base ligand and its copper(II) complexes
摘要： The present work describes the synthesis and characterization of a novel pyrene-naphthalene based Schiff base ligand and its copper complexes. The ligand was synthesized by reacting 1-Pyrenecarboxaldehyde and 1,8-Diaminonaphthalene in 2:1 molar ratio. The resulting Schiff base ligand, (N1E,N8E)-N1,N8-bis(pyren-1-ylmethylene)naphthalene-1,8-diamine (BPND) was characterized by NMR (1H and 13C), FT-IR and ESI-HRMS techniques. Further, BPND was used to synthesize two Cu(II) complexes (1 and 2) in 2:1 (ligand:metal) and 1:1:1 (ligand:metal:8-hyroxyquinoline) molar ratio, and characterized using electronic absorption, fluorescence spectroscopy, in addition to aforementioned spectroscopic techniques. DFT calculations have been used in order to obtain information on quantum-molecular descriptors reflecting the local reactivity properties. DFT calculations encompassed geometrical optimizations of title molecules and calculations of molecular electrostatic potential (MEP), average local ionization energies (ALIE) and atomic Fukui indices.
关键词： DFT,Fukui indices.,Cu(II) complex,Pyrene-naphthalene ligand,Spectroscopic characterization
更新于2025-09-23 15:21:01
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Water Soluble Fluorescent Graphene Nanodots
摘要： Water soluble fluorescent graphene nanodots (GND) have been successfully prepared through a bottom up approach from brominated pyrene via alkaline hydrothermal condensation. FT-IR, UV-Vis, Raman, XRD, AFM, and TEM studies have shown the formation of (cid:2)OH group rich nano-dots having graphene features with an approximate size of 90 nm. Steady state and 3D fluorescence studies have shown efficient fluorescence emission with maximum at 540 nm upon excitation at 450 nm in pH (cid:3) 7. Plasmid deoxyribonucleic acid (plasmid DNA) and bovine serum albumin (BSA) have shown their interaction with GND, which was studied via fluorescence quenching of GND and BSA, respectively. Selective quenching of the Fo¨ rster resonance energy transfer (FRET) of BSA-GND conjugate via ascorbic acid (AA) has been used to construct a calibration curve for AA estimation with a linear range and limit of detection of 34.00–112.00 mmole/L respectively. GND has also shown and 31.343 mmole/L, turn offchemosensing towards concentration-dependent heavy metals like Pb2 +, Cu2 +, Hg2 + and Zn2 +. In-vitromulti-color fluorescence imaging has been observed in GND-labelled HeLa (human cervical cancer) and NIH-3T3 (mouse embryonic fibroblast) cell lines with better uptake by HeLa cells. GND also has shown very high viability for both the cell lines up to the tested concentration of 300 mg/mL.
关键词： fluorescence,graphene nanodots,F?rster resonance energy transfer,brominated pyrene,bovine serum albumin
更新于2025-09-23 15:21:01
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Plasmon-Assisted Energy Transfer in Hybrid Nanosystems
摘要： While direct optical excitation of carbon nanotubes activates only the tube species strictly matching the excitation source, excitation energy transfer processes provide a single excitation channel for all the nanotubes species in a sample. The requirement of an overlap between donor emission and acceptor absorption limits the poll of donors able to trasfer their excitation to the tubes, leaving the high-energy part of the solar spectrum excluded from such processes. Here it is shown that the grafting of small metal nano-particles to the tubes alters those rules, enabling energy transfer process from molecules for which the standard energy transfer process is strongly suppressed. The onset of an energy transfer band in the UV/blue spectral region is demonstrated for an hybrid gold-pyrene-nanotube system, yielding collective emission from all the tubes present in our samples upon excitation of pyrene.
关键词： gold nanoparticles,pyrene dye,carbon nanotubes,plasmonic hybrids,energy transfer
更新于2025-09-23 15:21:01
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Electronically-tuned 2-(2′-Hydroxyphenyl)-4-pyrenylthiazole through Bond Energy Transfer Donor-Acceptor Couples: Sensing and Biological Applications
摘要： A novel pyrene-conjugated 2-(20-hydroxyphenyl)thiazole probe (HPTP, 1) was prepared, and its photophysical and sensing properties were investigated and compared to those of four model compounds. HPTP effectively detects CN? and glycerol in DMSO, with “turn off” at 425 nm and “turn on” at 495 nm. The sensing ability of 1 towards CN? ions in DMSO, mediated by the hydrogen bonding-induced disaggregation of aggregates, resulted in the quenching of ESIPT emission at 425 nm. By contrast, in a DMSO–glycerol mixed medium, the aggregate size increased together with the increased degree of intermolecular π–π interactions between two pyrene units located on adjacent molecules, and resulted in partial inhibition of energy/charge transfer from the pyrene unit to the thiazole unit in the excited state. Excitation energy transfer with increased photostability of the ESIPT core was effectively demonstrated in Candida albicans cell lines.
关键词： Glycerol,Pyrene,CN?,Excited state intramolecular proton transfer,2-(2’-Hydroxyphenyl)thiazole,Aggregation-induced emission
更新于2025-09-23 15:21:01
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Pyrene[4,5-d]imidazole-based Derivatives with Hybridized Local and Charge Transfer State for Highly Efficient Blue and White Organic Light-emitting Diodes with Low Efficiency Roll-off
摘要： A family of pyrene[4,5-d]imidazole derivatives, PyPA, PyPPA, PyPPAC and PyPAC, with different excited state are successfully developed. Among them, PyPPA and PyPPAC possess hybridized local and charge transfer (HLCT) state endowing them with pure blue fluorescence as well as high quantum yields. The nondoped organic light-emitting diode (OLED) based on PyPPA displays Commission Internationale de L’Eclairage coordinates of (0.14, 0.13) and achieves a maximum external quantum efficiency (EQE) of 8.47%, which are among the highest value reported to date for nondoped blue HLCT OLEDs. The nondoped OLED based on PyPPAC exhibits a maximum luminance of 50046 cd m-2 locating in blue region with CIE coordinates of (0.15, 0.21) and harvests the EQE of 6.74% even when the luminance reached over 10000 cd m?2. In addition, they both reveal ultimate exciton utilizing efficiencies of nearly 100%. The potential of blue emitter of PyPPA with HLCT character for application in white OLED (WOLED) is further tested. The efficient two-color hybrid warm WOLED is successfully achieved, which provides the total EQE, power efficiency and current efficiency of up to 21.19%, 61.46 lm W?1 and 62.13 cd A?1, respectively. The nondoped blue OLEDs and hybrid WOLEDs present good color stabilities with low efficiency roll-offs. Our results prove that taking advantage of the HLCT state, nondoped blue OLEDs as well as hybrid WOLEDs with high performance could be realized, which have a promising prospect for the displays and lightings in the future.
关键词： white OLED,blue luminophore,nondoped blue OLED,HLCT state,pyrene-imidazole
更新于2025-09-23 15:19:57