Abstract Electrochemical stimuli‐responsive systems via macrocyclic host–guest interactions are of practical significance in realizing functions of biological materials and synthetic molecular machines. In this study, a cyclo[6]aramide‐ferrocenium ( Fc + ) recognition motif was demonstrated to be a novel redox‐responsive system based on two‐dimensional (2D) macrocycle in organic media, in which the host strongly binds the oxidized form Fc + and shows no complexation towards the reduced form ferrocene. Results from cyclic voltammetric experiments clearly show the redox responsiveness of the claimed system, in sharp contrast to a control system based on an acyclic compound that contains the same number of introverted amide oxygens, highlighting the importance of the macrocyclic effect in the redox process. This study provides a rare example of using 2D hydrogen‐bonded aromatic amide macrocycles to form a ferrocene‐based redox‐responsive inclusion complex and thus paves the way for future applications.
Fused bicyclic cyclopropanols were achieved via an unprecedented HAT-triggered radical cascade reaction of alkene-tethered enones in the presence of an iron catalyst.
A technique is developed for photomodulated spectroscopy in a long-wavelength region, based on a step-scan Fourier transform infrared spectrometer. The experimental setup is discussed, and photoreflectance (PR) spectra of narrow-gap HgCdTe materials are given as examples at the wavelengths of 5 and 9μm. The photoluminescence spectra suggest that the PR features are related to the material fundamental gap. The signal-to-noise ratio and spectral resolution of the PR spectrum are quite good for line-shape analysis. The results indicate that the PR spectrum can be well fitted by a third-derivative line-shape function. Advantages and extendability are emphasized, and the potential for advancing the study of narrow-gap materials’ band structures is foreseen.
Temperature- and excitation-dependent modulated photoluminescence measurements are performed on narrow-gap liquid phase epitaxy (LPE) Hg 1-x Cd x Te (MCT). By combining with the second-order derivative and curve fitting, the band-acceptor transition is identified which is related to Hg vacancies. The energy level of this Hg vacancy locates at 12 meV (at 11 K) above the valence band.
Ge-Se thin film waveguide is used in optical devices because of its excellent optical properties. We investigated the structural and optical properties of as-deposited and thermally annealed Ge 18 Se 82 films and the associated waveguides. The optimized annealing condition at 170 °C was determined for Ge 18 Se 82 films. This study reveals that the annealing process can reduce the density of homopolar bonds and voids in the films. After the annealing process, Ge 18 Se 82 waveguides with the dimensions of 1.0 µm×4.0 µm and 1.5 µm×4.0 µm present 0.22 dB/cm and 0.26 dB/cm propagation loss reduction, respectively. This finding suggests that thermal annealing is an appropriate method for improving the performance of chalcogenide glass devices.
The Fe2+:ZnSe crystal is an important material for 3–5 μm mid-infrared lasers. In this work, we have grown different doping concentrations of Fe2+:ZnSe and Fe2+, Cr2+:ZnSe by the chemical vapor transport method. The doped crystals have the same structure. The lattice constant increases slightly with a higher Fe2+ concentration, while the doped Cr2+ has a great influence on the lattice constant. Besides, with a higher Fe2+ concentration, the TO mode has no change and the LO mode presents a small blue shift. The doped ZnSe crystals all have a wide absorption peak in the range of 2.3–4.5 μm, and these absorption peaks widen with the increase of the Fe2+ doping concentration. Besides, in the range of 5–20 μm, the crystals have good transparency. The concentrations of 3, 2, and 1% Fe2+ samples are calculated to be 4.15 × 1019, 3.27 × 1019, and 3.02 × 1019 cm–3, respectively, and the Fe2+ concentration of the Fe2+, Cr2+:ZnSe sample is 3.71 × 1019 cm–3. The band gap decreases from 2.52 to 2.27 eV with a higher Fe2+ doping concentration. Therefore, we can modulate the absorption bandwidth and band gap by doping the ion concentration, which is more suitable for developing mid-infrared gain medium applications.
A novel molecularly imprinted electrochemiluminescence (MIECL) sensor based on the luminescence of molecularly imprinted polymer-perovskite (MIP-CsPbBr 3 ) layer and Ru(bpy) 3 2+ was fabricated for simazine detection. MIP-CsPbBr 3 layers were immobilized onto the surface of glassy carbon electrode as the capture and signal amplification probe, and Ru(bpy) 3 2+ and co-reactant tripropylamine exhibited stronger electrochemiluminescence (ECL) emission. Under optimal conditions, the ECL signal of the MIECL sensor was linearly quenched, with the logarithm of simazine concentration ranging from 0.1 μg/L to 500.0 μg/L, correlation coefficient of 0.9947, and limit of detection of 0.06 μg/L. The practicality of the developed MIECL sensor method for simazine determination in biological samples was validated. Excellent recoveries of 86.5%–103.9% with relative standard deviation below 1.6% were obtained for fish and shrimp samples at three different spiked concentrations. The MIECL sensor exhibited excellent selectivity, sensitivity, reproducibility, accuracy, and precision for simazine determination in actual biological samples.
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