Latest ArticlesThree bench-stable difluoromethylene phosphonate hydrazones were prepared from simple diethyl(difluoromethyl)phosphonate within two steps in good yields. The [3 + 2] cycloaddition reaction of these diazo precursors with aryl diazonium salts has been accomplished under metal-free conditions with exclusive regioselectivity. This transformation provides practical access to a broad panel of 2-aryl-2H-tetrazol-5-yl difluoromethylene phosphonates, including the corresponding derivatives of amino acid (phenylalanine) and drug cores (Pomalidomide and Lapatinib fragment).
We demonstrate hole-transport-layer-free light-emitting diodes (LEDs) based on solution-processed multiple-quantum-well (MQW) perovskite. The MQW perovskite can self-assemble to a unique structure of vertically graded distribution with two-dimensional layered perovskite covered by three-dimensional-like perovskite at top, which can naturally form a barrier of electron transporting to the anode interface, thereby enhancing the charge capture efficiency. This leads to hole-transport-layer-free MQW perovskite LEDs reaching an external quantum efficiency (EQE) of 9.0% with emission peak at 528 nm, which is over 6 times of LEDs based on three-dimensional perovskite with the same device structure, representing the record EQE of hole-transport-layer-free perovskite LED.
Pomalidomide is an immunomodulatory agent (IMiD) that has been approved by the US Food and Drug Administration (FDA) for clinical treatment of patients with multiple myeloma. In this work, we developed a sensitive and validated LC-MS/MS method for high-throughput determination of pomalidomide over the range of 1.006–100.6 ng/mL (R2 = 0.9991) in human plasma and pharmacokinetic studies. A liquid-liquid extraction method using ethyl acetate was applied to extract pomalidomide and afatinib (as an internal standard, IS) from human plasma. Chromatographic separation was performed on a Hedera ODS column (150 mm × 2.1 mm, 5 µm) with security guard C18 column (4 mm × 2.0 mm) at 40 ℃. Methanol and 10 mmol/L aqueous solution of ammonium acetate containing 0.1% formic acid were used as a gradient elution mobile phase, and the flow rate was 0.4 mL/min. A triple quadruple tandem mass spectrometer using multiplex reaction monitoring mode (MRM) with electrospray ionization (ESI) positive ionization was employed. The precursor to product ion transitions for the quantitative analysis of pomalidomide and the IS were m/z 274.2→163.1 and m/z 486.1 → 371.1, respectively. This established method has been validated according to regulatory guideline, and the results were all within the acceptance criteria. The validated LC-MS/MS method was successfully applied to analyze samples obtained from clinical pharmacokinetics study after oral administration of pomalidomide (4 mg) capsules in human.
To address the challenge of treating complex pollutants containing heavy metals and organic compounds, a phenanthroline/TiO2 nanocomposite with rich oxygen vacancy defects was synthesized to integrate the functions of pollutant detection, adsorption, and photocatalytic degradation. The results showed that the nanocomposite could adsorb Cr3+ and the process could be transduced into a colorimetric signal for qualitative and quantitative detection. The adsorbed heavy metal also exhibited a synergistically enhanced photocatalytic degradation of a model organic pollutant under visible light. The simultaneous adsorption, detection, and photocatalysis could reduce the multifarious operations and high cost of traditional environmental remediation methods, indicating a strong application potential for the nanocomposite.
In this paper, the crystallization behavior of a novel poly(monothiocarbonate), poly(trimethylene monothiocarbonate) (PTMMTC), was investigated and compared with its polycarbonate analogue, poly(trimethylene carbonate) (PTMC). It is found that PTMMTC exhibits strong crystallizability, while unstretched PTMC is amorphous. DSC and DMA results reveal that PTMMTC possesses higher glass transition temperature (Tg) and β-transition temperature (Tβ) than PTMC. Simulation based on density functional theory (DFT) shows that, the bond angle of C-S-C is evidently smaller than that of C-O-C, and thus a larger dipole moment. This leads to the stronger intermolecular interaction and more rigid chain conformation in PTMMTC, which is the origin of sulfur-substitution enhanced crystallization. The crystal structure of PTMMTC was preliminarily determined for the first time. PTMMTC has an orthorhombic crystal structure with a planar zig-zag chain conformation. The parameters of unit cell are a = 10.74 Å, b = 4.79 Å, and c (fiber axis) = 7.74 Å.
Si coordination structures have been proven to greatly influence the ammonia-selective catalytic reduction (NH3-SCR) catalytic properties and the hydrothermal stability of Cu-based silicoaluminophosphate-form catalysts. However, the role of various Si coordination structures in the NH3-SCR reaction over Cu-SAPO-34 catalyst remains unknown. Herein, a batch of Cu-SAPO-34 samples with various Si contents was synthesized via a one-pot method to study the role of Si coordination structures in the NH3-SCR catalytic properties and hydrothermal stability. Cu/34–2 with the highest proportion of Si(xOAl) (x = 1~3) structures exhibits remarkable durability with 90% NO reduction efficiency within 200~450 ℃ even after a hydrothermal aging treatment at 850 ℃. In contrast, Cu/34–1 and Cu/34–4 with the highest proportions of Si(4OAl) and Si(0OAl) structures, respectively, are significantly deactivated by the same hydrothermal treatment. To better understand this phenomenon, the relationship between the Si coordination structures and SCR performance is established using characterization techniques and kinetics measurements. Results reveal that a high content of Si(4OAl) and Si(0OAl) is detrimental to the hydrothermal stability of Cu-SAPO-34 catalyst. However, Si(xOAl) (x = 1~3) structures are conducive to the stabilization of isolated Cu2+, thus enhancing the stability to severe hydrothermal treatment.
A reliable and sensitive strategy which can assess nucleic acid levels in living cells would be essential for fundamental research of biomedical applications. Some nanomaterial-based fluorescence biosensors recently developed for detecting nucleic acids, however, are often with expensive, complicated and time-consuming preparation process. Here, by using a facile bottom-up synthesis method, a two-dimensional (2D) coordination polymer (CP) nanosheet, [Cu(tz)] (Htz = 1, 2, 4-triazole), was successfully prepared after optimizing reaction conditions. These ultrathin CP nanosheets with thickness of 4.7 ± 1.1 nm could readily form nanosensors by assembly with DNA probes, which exhibited a low limit of detection (LOD) for p53 DNA fragment as 144 pmol/L. Furthermore, by integrating [Cu(tz)] nanosheets with hybridization chain reaction (HCR) probes, miR-21, one kind of microRNA upregulated in many cancer cells, can be sensitively detected with a LOD of 100 pmol/L and monitored in living cells, giving consistent results with those obtained by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis. Thus [Cu(tz)] nanosheets, which not only possess much better nucleic acids sensing performance than bulk cystals, but also exhibit nucleic acid delivery functions, could be used as a novel nanoplatform in biomedical imaging and sensing applications.
The preparation of amorphous pure organic room-temperature phosphorescence materials with high efficiency is still a challenging task. Herein, we introduce a CB[6] derivative-based supramolecular self-assembling strategy. A water soluble and ellipsoidal deformed CB[6] derivative is used to self-assemble with 4-(4-bromophenyl)-1-methylpyridin-1-ium chloride, bromide and hexafluorophosphate in water. After freeze-drying, the obtained amorphous complexes exhibit brilliant green phosphorescence emission under ambient conditions, with phosphorescence efficiency up to 59%, 60% and 72%, respectively. This is the first report of amorphous non-polymeric pure organic room-temperature phosphorescence with such a high efficiency. In view of the dynamic self-assembling property, the complexes are responsive to water, which could enable information encryption.
We report supramolecular AND logic gates based on host-guest complexation between acid-labile acyclic cucurbit[n]uril (CB[n]) molecular container and NaClO-responsive dye. Supramolecular AND logic gate is turned on due to acid-triggered degradation of molecular container and the release of the dye, followed by NaClO-induced fluorescence "switch on" effect of the dye. The reason for AND molecular logic gate is discovered to be the combination of oxidation inhibition and fluorescence "switch off" effect. Supramolecular AND logic gate is confirmed to be operational in live MCF-7 and HeLa cancer cells.
In this work, the nano-g-C3N4/UiO-66-NH2 composite was prepared by one-step solvothermal method. The as-prepared composite was characterized by scanning electron microscopy, Brunner-Emmet-Teller measurement, energy dispersive spectrometer, X-ray diffraction, and Fourier transform infrared spectroscopy. By using nano-g-C3N4/UiO-66-NH2 composite as sorbent, a dispersive solid-phase extraction coupled with high-performance liquid chromatography was developed to sensitive analysis of food colorants including tartrazine, amaranth, carmine, sunset yellow, allura red and bright blue. The experiment parameters including the amount of sorbent, adsorption time, the pH of adsorption solution, desorption time, desorption solvent, the pH of desorption solution as well as the proportion between desorption solvent and buffer solvent were investigated. Under the optimized conditions, the limits of detection (S/N = 3) and limits of quantitation (S/N = 10) were determined in the ranges of 0.08–0.8 and 0.2–2.0 ng/mL, respectively. With the developed sample pretreatment method, carmine and brilliant blue were determined from blueberry juice by HPLC-DAD. The contents were calculated as 1.53 µg/mL and 0.17 µg/mL, respectively.
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