查看更多>>摘要：Three new Cd(II) coordination polymers (CPs) [Cd(opda) (tib)]·H2O (1), [Cd4(mpda)4(tib)2(dib)2]·7H2O (2), [Cd (ppda) (tib)]·4H2O (3), have been synthesized by using isomeric phenylenediacetates (H2pda) and 1,3,5-tris(1-imidazolyl)benzene (tib) ligand under hydrothermal condition. Single crystal X-ray structures showed that CP 1 constitutes 3,5-connected 2-nodal net with a three-dimensional (3D) structure, while CP 2 forms an ring 1D chain, CP 3 has a interpenetrated 2D structure. The structural diversity of these CPs is mainly attributed to the different coordination modes and isomer conformations of the flexible phenylenediacetic acids. Three CPs are highly selective and sensitive luminescent sensors toward tetracycline (TEC). Compared with CPs 2 and 3, CP 1 has higher quenching percentage and adsorption capacities (64.493 mg g~(-1)) for TEC due to its large specific surface area (171.72 m~2 g~(-1)) and pore volume (0.31 cm~3 g~(-1)). The main adsorption mechanisms are phys-isorption and chemisorption, including pore filling effect and π-π interaction. This study provides new insights into the design of 3D CPs for removing pollutants from industrial wastewaters, with the potential to mitigate health risks to humans and natural ecosystems.
Mikhail B. BerezinSofya A. DogadaevaElena V. Antina
10页
查看更多>>摘要：Unsymmetrically substituted boron(III) and zinc(II) dipyrromethenates were synthesized in high yields, and the physico-chemical investigation results of them are presented. Comparative analysis of luminescence properties in a series of various organic solvents, photo- and thermal stability was carried out depending on the molecular structure. For the first time it was established that the methyl group absence in a-, p- or p'-position of one of the pyrrole fragments changes properties of pentamethyl-dipyrromethene ligands and complexes differently. It is shown unsubstituted α- or β-position of one pyrrole cycle leads to a hypsochromic shift of the maximum of the intense absorption band and free β'-position - to bathochromic shift. In the general case, the fluorescence quantum yield of BODIPY reaches 99% and depends little on the solvent properties. However, BODIPY unsubstituted in one of the α-position showed a sharp decrease of the fluorescence quantum yield upon going from non-polar solvents to polar. Unsymmetrically substituted zinc(II) dipyrromethenates are characterized by low value of the fluorescence quantum yield, the fluorescence almost completely quenching in weakly polar and polar solvents. It is found that the unsymmetrically substitution increases photostability of boron(III) and zinc(II) complexes but decreases their thermal stability in solid state.
查看更多>>摘要：Hypoxia is one of the common characteristics in tumor cells. It has been confirmed that the nitro reductase (NTR) overexpression is closely related to hypoxia cells. Thus, developing a facile method to detect nitro reductase is of great significance. Although several detection techniques have been designed for the NTR, these probes still have limitations, such as low sensitivity, poor water solubility, and compromised biocompatibility. In this study, we developed a nanocomposite (Nitro-BOD@ZIF-8) based on BODIPY fluorophore and zeolitic imidazolate framework-8 (ZIF-8). A red emission BODIPY small molecule probe (Nitro-BOD) was synthesized and then encapsulated in ZIF-8. Morpholine and nitro groups were introduced to Nitro-BOD for lysosome localization and NTR detection, respectively. The results showed that reduction of the nitro group on the probe by NTR blocked the photoinduced electron transfer (PET), resulting in fluorescence enhancement. The low detection limit for the NTR proved the sensitivity of the sensor. In addition, confocal microscopy con-firmed the fluorescence imaging feature of the Nitro-BOD@ZIF-8 for NTR in A549 cells. This work also opens a useful path for probe and MOF in the field of enzyme detection.
查看更多>>摘要：This study presents bulk configuration large-area luminescent solar concentrators (LSCs) incorporating a novel organic fluorophore (TPP1) based on tetraphenylpyrazine core symmetrically functionalized with electron-rich dimethylamine (donor) and electron-deficient cyano (acceptor) moieties. As confirmed experimentally and validated through a computational approach, TPP1 exhibits aggregation-induced emission and a large Stokes shift due to intramolecular charge transfer, making it an excellent candidate as a fluorophore in poly(methyl methacrylate) based LSCs. Based on promising photophysical properties, TPP1 LSCs with suitable concentration showed an internal and external photon efficiency of 23.7% and 2.33% under AM 1.5G illumination, respectively. The size scalability (up to 100 cm length) of TPP1 LSCs was also evaluated by employing analytical models. Moreover, the power conversion efficiency of 10 × 10 × 0.3 cm~3 LSC (geometrical factor 8.33) was found to be 0.66% and 0.34%, with and without scattering background, respectively. Such outstanding optical and PV performances of TPP1 LSCs clearly illustrate that TPP1 with combined AIE and ICT features is a viable alternative to most organic dyes. Additionally, stability and aesthetics analysis of TPP1 LSCs also suggest their long-term use and compatibility with the built environment.
查看更多>>摘要：Two novel aggregation-induced emission (AIE) active Schiff bases (P4C12 and P5C12) harnessing excited-state intramolecular proton transfer (ESIPT) process derived from tetraphenylethylene and 4-(dodecyloxy)-2-hydroxybenzaldehyde were reported. P4C12 exhibits photochromism in original powder and crystalline states. In contrast, P5C12 exhibits photochromism in original powder, but totally different photochromic and fluorescence properties in its two crystalline polymorphs. The reed leaf crystal (P5C12-A) exhibits very weak fluorescence and reversible photochromic behavior, while the small block crystal (P5C12-B) emits relatively stronger fluorescence without photochromism. Detailed investigations indicate that, different crystal packing styles result in different photoinactivation ways, accounting for different photochemical and photophysical properties. As photochromic molecules, P4C12 and P5C12 show reversible color and fluorescence changes upon UV light irradiation and visible light with good fatigue resistance, which makes them suitable for data storage and anti-counterfeiting materials. Moreover, P4C12 shows anisotropic crystal without liquid crystal texture, while P5C12 shows reversible liquid crystal with smectic phase.
查看更多>>摘要：Facile and accurate temperature measurement is crucial in daily life, industrial applications, and scientific research. Here, we present a new strategy for physiolpgical temperature sensing based on dual-emission from second harmonic generation (SHG) signal and two-photon luminescence in a dye-loaded nonlinear metal-organic framework (MOF) composite FIR-8(∪)DMASM (DMASM = 4-[p-(dimethylamino)styryl]-1-methylpyridinium). Powder X-ray diffraction (PXRD), thermal gravimetric analysis (TGA), infrared absorption spectrum, single-photon luminescence, and the quantum yield indicate that encapsulation not only provides a two-photon luminescence center, but also improves the stability and quantum efficiency of dyes. Temperature-dependent spectroscopy shows that FIR-8(∪)DMASM has excellent sensory performance in the physiological temperature region (20-60 °C) with high relative sensitivity of 1.36-2.98% °C~(-1). With good water stability and excellent biocompatibility, FIR-8(∪)DMASM can be potentially applied in biological temperature sensing.
查看更多>>摘要：A chemical clock reaction is a process where a periodic change in color is observed with the progress of a reaction. Nonlinear kinetic clock reactions are associated with a visible color change caused by redox phenomena or a change in the concentration of certain dye components. The redox activities of dyes are dependent on the reaction conditions and catalyst used. This review is based on the clock reaction using organic dyes. The choice of dye was based on the properties, such as water solubility. The dyes must show distinct and different visible color variations in the oxidation and reduction state of dyes. The various dyes were tested for the following: (1) color variation; (2) redox behavior of different dyes in various catalytic systems; (3) rate determination of clock reactions with the alteration of dyes; (4) study of the interaction of dyes with the catalyst and reaction medium. Water-soluble organic dyes can be applied as a redox indicator, where the redox behavior of dyes and the nature of catalysts are responsible for the alteration of formal oxidation and reduction potential values. Catalytic modifications were carried out to control the rate of the clock reaction to identify the redox kinetics in a free solution or organized media, such as micelles and reverse micelles. The use of nano-catalysts broadened the use and application range of the clock reaction. A wide range of pH can be used to control the redox activity of dyes and the rate of the clock reaction that might significantly improve the clock cycles. The visual detection of oxidation-reduction is simple to monitor using common instruments, such as UV-vis spectroscopy. Clear and concise documents for the clock reaction from classical blue bottle experiments and their development with various catalytic systems and modern and rapid versions are also included. A brief plausible mechanism for synthesizing catalytic systems and their effect on clock reactions are discussed. The difference in the clock reactions with adsorption and degradation are also described. The importance of the clock reactions in various fields is also documented.
查看更多>>摘要：This paper examines the suitability of azaindole appended pyridine core for selective sensing of Zn~(2+). The designed probe (TryPy) was prepared from biologically important tryptamine and pyridine-2-carboxaldehyde. TryPy gave a LOD of 0.15 μM of Zn~(2+), with a binding stoichiometry of 1:1. It exhibited a superior detection of Zn~(2+) in the presence of various cations and anions tested, including well-known interfering ions Cd~(2+) and Hg~(2+). Excitation experiments indicated the plausible mechanism of detection to be ESIPT which was validated by TD-DFT analysis. Neutral and weak acidic environments were most appropriate for Zn~(2+) detection. The developed Zn~(2+) probe demonstrated logic gate applications and was used for eukaryotic cell imaging.
查看更多>>摘要：Three new thiophenyl bridged triarylamine-donor based dyes with pyridyl anchoring groups and indolium acceptors have been synthesized and studied as sensitizers for the p-type dye-sensitized solar cell (p-DSSC). Compared to known dicyano and pyridinium dyes with the same triarylamine cores, these new sensitizers have broadened and red-shifted UV-vis absorption spectra, with high extinction coefficients and absorption extending beyond 700 nm. TD-DFT calculations on the indolium family indicate that these dyes combine strong donor acceptor communication, with a high degree of charge separation in the excited state - an ideal combination for sensitizer dyes. The phenylpyridyl anchored bis-indolium gives the highest power conversion efficiency (0.097%) through a short circuit photo-current (Jsc) of 3.04 mA cm~(-2), open circuit voltage (V_(OC)) of 97 mV and fill factor of 36%. This exceeds the performance of the P1 reference dye in this study, and represents the best performance so far for a cationic, pyridine anchored p-DSSC dye.
查看更多>>摘要：The latest tools for applications in chemical, environmental, and biological sciences are based on stimuli-responsive materials. Due to their easy detectable output, fluorochromic probes able to provide photo-luminescence response to a given parameter/analyte are in high demand. Here, we designed a monodimensional coordination polymer by zinc-driven self-assembly of symmetrical N,O mononegative ligands containing a flexible spacer. This easy-to-synthesize polymer exhibits the processability of organic polymers and an interesting emission pattern. By annealing the polymer above the glass transition temperature, a relevant fluorochromism was detected. The emission undergoes to a red-shift, turning its turquoise-blue emission to yellow emission, and accompanied by a decrease of the photoluminescence quantum yield of about 2.5 fold. Guided by a cross-analysis based on X-ray structural study, PL, FTIR data, and DFT calculations we explored the mechanism involved in the thermo-induced fluorochromism. We could associate the phenomenon to a structural rearrangement of the coordination environment, involving the pivotal role of zinc, which in turn leads to a change in the dimensionality of the polymer.
NSTL