Sensing Performance Enhancement via Acetate-Mediated N-Acylation of Thiourea Derivatives: A Novel Fluorescent Turn-On Hg²⁺ Chemodosimeter

A Hg²⁺ chemodosimeter <b>P3</b> derived from a perylenebisimide scaffold and thiourea fragments was systematically studied with focus on the photophysical, chemodosimetric mechanistic, as well as fluorogenic behaviors toward various metal cations for the sake of improving selectivity to Hg²⁺. As demonstrated, Hg²⁺ can promote a stepwise desulfurization and N-acylation of <b>P3</b> with the help of an acetate anion (OAc^–), resulting in an N-acylated urea derivative. Interestingly, OAc^– has the effect of improving the selectivity of <b>P3</b> to Hg²⁺ among other metal ions; that is, in an acetone/Britton–Robinson buffer (9:1, v/v; pH 7.0) upon excitation at 540 nm, the relative fluorescence intensity is increased linearly with increasing concentration of Hg²⁺ in the range of 2.5–20 μM with a detection limit of 0.6 μM, whereas the fluorescence intensity of <b>P3</b> to other metal ions, including Na⁺, K⁺, Mg²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Ni²⁺, Co²⁺, Zn²⁺ Ag⁺, Cd²⁺, Pb²⁺, and Cu²⁺, is negligible. The fluorescent bioimaging of chemodosimeter <b>P3</b> to detect Hg²⁺ in living cells was also reported

A Multiaddressable Photochromic Bisthienylethene with Sequence-Dependent Responses: Construction of an INHIBIT Logic Gate and a Keypad Lock

A photochromic bisthienylethene derivative (<b>BIT</b>) containing two imidazole units has been synthesized and fully characterized. When triggered by chemical ions (Ag⁺), protons, and light, <b>BIT</b> can behave as an absorbance switch, leading to a multiaddressable system. <b>BIT</b> exhibits sequence-dependent responses via efficient interaction of the specific imidazole unit with protons and Ag⁺. Furthermore, an INHIBIT logic gate and a keypad lock with three inputs are constructed with the unimolecular platform by employing an absorption mode at different wavelengths as outputs on the basis of an appropriate combination of chemical and photonic stimuli

DataSheet1_Potential distribution prediction of Deyeuxia angustifolia in the Tumen River Basin and analysis of major impact factors.docx

Deyeuxia angustifolia acts as an indicator of the changes in wetland ecosystems and plays an important ecological role in their functions. Previous studies have shown that the Tumen River Basin is of wide global interest as a transboundary basin area with abundant wetland ecological resources. Despite the implementation of wetland conservation measures in recent years, the distribution area of D. angustifolia in this basin has been reduced due to climate change and anthropogenic activities. Therefore, we used MaxEnt and geographic information system to model a suitable habitat for this species, simulated changes in the habitat, and applied Jackknife to assess the influencing environmental variables. The Jackknife tests showed that slope orientation, solar radiation in September, and total nitrogen were the dominant environmental factors affecting the potential distribution of D. angustifolia. Compared to the current distribution, the total area of land highly and moderately suitable for this species will decrease in the 2050’s and 2070’s, respectively, under two representative concentration paths (RCPs), shifting the centroid of its suitable area and direction of wetland degradation to the northeast. Our study of the projected potential distribution of D. angustifolia in the basin under future climate change could provide important information for its conservation, management, sustainable use, and early warning to prevent its extinction.</p

α‑Monoacylated and α,α′- and α,β′-Diacylated Dipyrrins as Highly Sensitive Fluorescence “Turn-on” Zn²⁺ Probes

With the purpose of developing readily synthesized CHEF (chelation-enhanced fluorescence) type Zn²⁺ probes with relatively simple molecular structures and excellent sensing behavior, <i>p</i>-anisoyl chloride was used for the acylation of 5-(penta­fluoro­phenyl)­dipyrro­methane. Interestingly, the α,β′-diacylated product <b>PS2</b> with a unique substitution mode was obtained in high yield in addition to the normal α-substituted mono- and diacylated products <b>PS1</b> and <b>PS3</b>. Further oxidation of <b>PS1</b>–<b>PS3</b> afforded dipyrrins <b>S1</b>–<b>S3</b>. Crystal structure and ¹H NMR measurements of <b>S2</b> demonstrate the existence of a pure tautomer, which is consistent with DFT calculations. <b>S1</b>–<b>S3</b> show highly Zn²⁺ selective “turn-on” fluorescence based on a CHEF mechanism by the formation of 2:1 (probe:metal) Zn²⁺ complexes. The emission colors can be easily tuned from green to red by changing the dipyrrin substitution modes. Furthermore, these probes demonstrate fast responses and wide applicable pH ranges. Among them, <b>S2</b> shows the highest Zn²⁺ sensitivity, with a detection limit of 4.4 × 10^–8 M

D-A-π-A Featured Sensitizers Bearing Phthalimide and Benzotriazole as Auxiliary Acceptor: Effect on Absorption and Charge Recombination Dynamics in Dye-Sensitized Solar Cells

Two organic D-A-π-A sensitizers <b>LS-2</b> and <b>WS-5</b> containing <i>N</i>-octyl substituted phthalimide and benzotriazole as auxiliary electron withdrawing units with similar dimension and structure architecture were systematically studied, focusing on photophysical and electrochemical as well as photovoltaic properties in nanocrystalline TiO₂-based dye-sensitized solar cells (DSSCs). Interestingly, with similar five-member benzo-heterocycles, the two auxiliary acceptors of phthalimide and benzotriazole play exactly different roles in absorption and intramolecular charge transfer: (i) in contrast with <b>WS-5</b> delocalized throughout the entire chromophore, the HOMO orbital of <b>LS-2</b> is mainly located at the donor part due to the twist conformation with the existence of two carbonyl groups in phthalimide; (ii) the dihedral angles of “D-A” plane and “A-π” plane in <b>LS-2</b> further suggest that the incorporation of phthalimide moiety results in curvature of electron delocalization over the whole molecule, in agreement with its blue-shifted, relatively narrow absorption spectra and low photocurrent density; (iii) in contrast with the beneficial charge transfer of benzotriazole in <b>WS-5</b>, the phthalimide unit in <b>LS-2</b> plays an oppositely negative contribution to the charge transfer, that is, blocking intramolecular electron transfer (ICT) from donor to acceptor to some extent; and (iv) in electrochemical impedance spectroscopy, the incorporated benzotriazole unit enhances electron lifetime by 18.6-fold, the phthalimide only increases electron lifetime by 5.0-fold. Without coadsorption of chenodeoxylic acid (CDCA), the DSSCs based on <b>WS-5</b> exhibited a promising maximum conversion efficiency (η) of 8.38% with significant enhancement in all photovoltaic parameters (<i>J</i>_SC = 15.79 mA cm^–2, <i>V</i>_OC = 791 mV, <i>ff</i> = 0.67). In contrast, with the very similar D-A-π-A feature changing the additional acceptor from benzotriazole to phthalimide unit, the photovoltaic efficiency based on <b>LS-2</b> was only 5.11%, decreased by 39%, with less efficient photovoltaic parameters (<i>J</i>_SC = 10.06 mA cm^–2, <i>V</i>_OC = 748 mV, <i>ff</i> = 0.68). Therefore, our results demonstrate that it is essential to choose proper subsidiary withdrawing unit in D-A-π-A sensitizer configuration for DSSCs

α‑Monoacylated and α,α′- and α,β′-Diacylated Dipyrrins as Highly Sensitive Fluorescence “Turn-on” Zn²⁺ Probes

With the purpose of developing readily synthesized CHEF (chelation-enhanced fluorescence) type Zn²⁺ probes with relatively simple molecular structures and excellent sensing behavior, <i>p</i>-anisoyl chloride was used for the acylation of 5-(penta­fluoro­phenyl)­dipyrro­methane. Interestingly, the α,β′-diacylated product <b>PS2</b> with a unique substitution mode was obtained in high yield in addition to the normal α-substituted mono- and diacylated products <b>PS1</b> and <b>PS3</b>. Further oxidation of <b>PS1</b>–<b>PS3</b> afforded dipyrrins <b>S1</b>–<b>S3</b>. Crystal structure and ¹H NMR measurements of <b>S2</b> demonstrate the existence of a pure tautomer, which is consistent with DFT calculations. <b>S1</b>–<b>S3</b> show highly Zn²⁺ selective “turn-on” fluorescence based on a CHEF mechanism by the formation of 2:1 (probe:metal) Zn²⁺ complexes. The emission colors can be easily tuned from green to red by changing the dipyrrin substitution modes. Furthermore, these probes demonstrate fast responses and wide applicable pH ranges. Among them, <b>S2</b> shows the highest Zn²⁺ sensitivity, with a detection limit of 4.4 × 10^–8 M

Near-Infrared Colorimetric and Fluorescent Cu²⁺ Sensors Based on Indoline–Benzothiadiazole Derivatives via Formation of Radical Cations

The donor–acceptor system of indoline–benzothiadiazole is established as the novel and reactive platform for generating amine radical cations with the interaction of Cu²⁺, which has been successfully exploited as the building block to be highly sensitive and selective near infrared (NIR) colorimetric and fluorescent Cu²⁺ sensors. Upon the addition of Cu²⁺, an instantaneous red shift of absorption spectra as well as the quenched NIR fluorescence of the substrates is observed. The feasibility and validity of the radical cation generation are confirmed by cyclic voltammetry and electron paramagnetic resonance spectra. Moreover, the introduction of an aldehyde group extends the electron spin density and changes the charge distribution. Our system demonstrates the large scope and diversity in terms of activation mechanism, response time, and property control in the design of Cu²⁺ sensors

Light-Triggered Reversible Supramolecular Transformations of Multi-Bisthienylethene Hexagons

It is very challenging to realize well-controlled structural transformations in artificial supramolecules. Herein we report the construction of a novel family of multi-bisthienylethene hexagons with precise control of the shape and size as well as the specific number of photochromic units via coordination-driven self-assembly. These newly developed multi-bisthienylethene hexagons are highly sensitive and responsive to photostimuli, especially allowing for quantitative reversible supramolecular transformations triggered by light irradiation

Screen-Printed Red Luminescent Copolymer Film Containing Cyclometalated Iridium(III) Complex as a High-Permeability Dissolved-Oxygen Sensor for Fermentation Bioprocess

The novel hydrophobic luminescent copolymer P­(Ir-TFEMA) was developed as an online dissolved-oxygen (DO) sensor. The phosphorescent moiety of cyclometalated iridium­(III) complex exhibits red emission near 650 nm with a large Stokes shift of about 245 nm and minimal optical interference from the fermentation system. The covalent incorporation of the chromophore into the polymeric matrix rather than physical doping was used to avoid phase-separation and leaching problems. The low molar ratio between the introduced chromophore and polymeric matrix within the range of 1:135–1:250 was confirmed to have little influence on the luminescence response ability. To assess its potential utility, this copolymer was applied to the online monitoring of DO during the cephalosporin C fermentation process. The screen-printing technique was utilized as a rapid and reliable automatic approach to preparing sensor films with good photostability and fatigue resistance, showing promise in bioprocess monitoring as a low-cost DO indicator for high-throughput microbioreactors

Optimizing the Chemical Recognition Process of a Fluorescent Chemosensor for α‑Ketoglutarate

α-Ketoglutarate (α-KA) can convert to 2-hydroxyglutarate (2-HG), which is confirmed to be associated with many diseases, especially with acute myeloid leukemia (AML). In this paper, a novel reaction-based chemosensor DT based on the typical Schiff-base reaction was designed for sensing the biomarker of α-KA, in which a diazanyl group as the recognition group was linked with a benzothiadiazole unit as the fluorophore moiety. Considering the typical Schiff-base reaction to generate hydrazones suffering from slow kinetics, particularly under neutral conditions, a series of parallel experiments was conducted for optimizing the chemical recognition process, including varying the solvent, reaction temperature, reactant concentration, and reaction rate. The optimum condition was established as a pH value, temperature, α-KA concentration, and response time of 5.7, 30 °C, 100 μM, and 20 min, respectively. Notably, in contrast with the initial 6.3-fold fluorescence enhancement, the remarkable 75-fold fluorescence enhancement ((<i>I</i> – <i>I</i>₀)/<i>I</i>₀ at 560 nm) was observed by optimizing the chemical recognition process of DT and α-KA. Finally, DT was carried out for the chemical recognition processing of α-KA in serum. We demonstrated that DT is selective for α-KA over other potential biologically interferences with similar structures and thus is suitable for detecting α-KA in serum. On the basis of the optimized chemical recognition process, DT shows high potential application for sensing α-KA with remarkable fluorescence enhancement. This work provided a potential method that is quick and convenient for sensing biomarker α-KA in serum. It is worth noting that without complicated pretreatment, utilizing a novel reaction-based fluorescent chemosensor may establish a new promising platform for clinical diagnosis biomarker