Nitro compounds are widely used in modern industries. Among them, 2, 4-dinitrophenylhydrazine (DNH) is extremely harmful. It is of great significance to develop methods for detection of DNH. In this work, chitosan was used as the substrate material, and fluoroborondipyrrole (BODIPY) was used as the fluorophores. The fluorescence sensing ability was endowed to chitosan by introduction of BODIPY units. Firstly, BODIPY derivatives (NO-3 and BO-1) with alkynyl group (C≡C) were synthesized. Secondly, small molecules NO-4 and BO-2 with aldehyde group (-CHO) were obtained. Finally, the -NH2 groups on chitosan occurred a click reaction (-NH2/C≡C) and a Schiff base formation reaction occurred (-NH2/-CHO) to obtain three polymer probes C1, C2 and C3. The C=C formed in click reaction can interact with DNH and can be used as recognizing sites for DNH. These chitosan probes have good thermal stability and could selectively recognize DNH, showing notable fluorescence quenching effects, which is visible to the naked eyes. DNH is a typical electron-deficient compound, and the polymer fluorescent probe contains electron-rich groups, which makes it easier for the two species to combine and cause fluorescence changes. C1 is flexible cross-linked, C3 is rigid cross-linked, and C2 is of a non-crosslinked structure, and they show different rheological properties. This work expands the application of chitosan.

Recently, tetracylines (TCs) has become the most used antibiotics in animal husbandry since it can kill most Gram-positive and negative bacteria. However, it is still a tough problem to accurately detect the residual TCs. Carbon dots (CDs) have attracted intensive attention owing to the excellent fluorescent performance, good biocompatibility and facile availability. Thus, many researches have been conducted to fabricate high-performance CDs fluorescence probes for the fast and accurate detection of TCs. Nevertheless, a comprehensive summary about the effective synthesis of CDs and their practical function in detecting TCs is still needed to further strengthen the wide application of CDs. We herein firstly made a detailed introduction of TCs and CDs. Then, based on the different synthetic technologies, the synthetic methods of CDs were divided into top-down and bottom-up strategies. In addition, from the different doped species, we classified the CDs fluorescent probes as undoped CDs, metal-doped CDs, nonmetal-doped CDs, co-doped CDs and CDs nanocomposites. Furthermore, the remained defects and prospects were highlighted to provide valuable guidance in preparing commendable CDs and detecting TCs.

Rational design and synthesis process are most important for giving the product an excellent performance. Sn-based anode materials with high theoretical capacity and suitable working potential usually suffer from severe capacity fading due to their inferior electronic conductivity and obvious volumetric variation, hindering their practical applications. Herein, hierarchical N doping graphene-supported SnO2/Zn2SnO4 (SnO2/Zn2SnO4-NG) are successfully prepared via a facile approach forming a 3D hierarchical configuration. As an anode for lithium-ion batteries, the SnO2/Zn2SnO4-NG anode can reach a high reversible capacity (837 mAh g-1 after 300 cycles at 0.2 A g-1) and rate capability (403 mAh g-1 at 5 A g-1) but also show extraordinary durability. Furthermore, it exhibits impressive rate performance and maintains superior cycling stability. Such significantly enhanced electrochemical performances of the SnO2/Zn2SnO4-NG anode can be attributed to the unique structural design, which can not only effectively reduce the stress from the discharging/charging process and maintain the structural stability of electrode during cycling but also alleviate aggregation of active material and facilitate electrolyte/ion transport. Meanwhile, the Zn2SnO4 can greatly improve electrical conductivity (confirmed by DFT calculations), and the SnO2/Zn2SnO4 can create more active sites for lithium storage. This work thus verifies the great potential of SnO2/Zn2SnO4-NG composite for applications as a high-performance anode material in next-generation Li storage.

A palladium-catalyzed decarboxylative domino reaction of imidazo[1,2-a]pyridines and coumarin-3-carboxylic acids has been developed, which provides access to dibenzoisochromenoimidazo[1,2-a]pyridin-6-ones possessing six fused rings.

Modifying backbone, side chains and end groups of non-fullerene acceptors (NFAs) in organic photovoltaics (OPVs) can tune their properties, and then impact on performance. Hence, understanding how the different functional groups influence properties and performances are critical for developing novel NFAs for OPVs. Here, to investigate the effects of introducing methyl groups and substituting dicyano with O, based upon extensive quantum chemistry calculations, we selected PM6:IT-4F heterojunction as reference system, and studied the geometries, electronic structures, excitation properties, electrostatic potentials (ESPs) of PM6, IT-4F, IM-4F and IO-4F, as well as PM6:IT-4F, PM6:IM-4F and PM6:IO-4F complexes as interface models. The rate constants of charge transfer (CT), exciton dissociation (ED) and charge recombination processes at heterojunction interface were also calculated. The results indicate that the better performance of PM6:IM-4F and PM6:IT-4F systems can be ascribed to redshift of optical absorptions that assure more photons can be harvested, larger ESP difference between PM6 and NFAs, and the larger excitation energy difference between NFA’s local excitation and CT that is favorable to efficient ED. However, the larger open-circuit voltage of PM6:IO-4F OPV results from that substituting dicyano with O generate a significant increase of the lowest unoccupied molecular orbital and CT excitation energies of PM6:NFA complexes, whereas the smallest short-circuit current density mainly related to less CT excitations, blue-shift optical absorption that isn’t complementary with that of PM6, inefficient ED and the smaller ESP difference between PM6 and IO-4F.

Novel hexaphenylbenzene derivatives (HPB-1 and HPB-2) were synthesized and their structural and optical properties were characterized by 1H NMR, 13C NMR, HRMS, absorption and fluorescence spectroscopies. The effect of various anions (AcOˉ, NO3ˉ, HSO4ˉ, ClOˉ, ClO4ˉ, SCNˉ, CNˉ, Fˉ, Clˉ, Brˉ, Iˉ and H2PO4ˉ) on the optical properties of these new compounds were investigated in THF. Among the different anions, significant changes in fluorescence spectra of HPB-1 and HPB-2 were observed in the presence of only Fˉ ions among different anions. The interaction ratios of HPB-1 and HPB-2 with Fˉ ions were determined to be 1:1 and the binding constants (KA) were found as 0.0417 M-1 and 0.982 M-1 for HPB-1 and HPB-2, respectively. LOD values were calculated as 2.79 µM and 1.04 µM for HPB-1 and HPB-2, respectively. The mechanism of Fˉ ion sensing was investigated by 1H NMR titration. The obtained results showed that the newly synthesized HPB-1 and HPB-2 compounds can be a turn-on fluorometric sensor with high selectivity for Fˉ ions.

A rhodium(I)-catalyzed regioselective hydroacylation of alkenyl-bearing allylic alcohols with simple aldehydes for the preparation of diverse 1,5-diketones is described. Mechanistic investigation suggests that this transformation might proceed through redox isomerization of the allylic alcohol followed by hydroacylation of the resulting enone with aldehyde involving a stable six-membered rhodacycle intermediate. This protocol highlights the role of in situ generated carbonyl group in controlling the site-selectivity of the intramolecular alkene moiety.

A facile solvothermally assisted g-C3N4 post-grafting technique with aromatic amine dyes via Schiff base chemical reaction was successfully developed in this study. Based on this strategy, three D-π-A type aromatic amine organic dyes (TPA-CNCHO, PTZ-CNCHO, and CZ-CNCHO) were covalently grafted to g-C3N4. The resulting composite photocatalyst was characterized using TEM, XPS, FT-IR, UV-Vis DRS, PL, and transient photocurrents, which confirmed the feasibility of the modification strategy. The values for the photocatalytic hydrogen production rates obtained for g-C3N4/TPA-CNCHO, g-C3N4/PTZ-CNCHO, and g-C3N4/CZ-CNCHO were 16232.7, 13266.9, and 11822.8 µmol·h-1·g-1 respectively. Each of these values is 40, 33, and 29 times higher than that of pure g-C3N4, respectively. Among them, g-C3N4/TPA-CNCHO exhibited the highest photocatalytic hydrogen-production activity and the highest recycling usage stability. In addition, a possible mechanism for the separation and transfer of photo-induced carriers was obtained based on DFT calculations and experimental results. This further confirmed that covalently post-grafting g-C3N4 with organic aromatic amine dyes through the Schiff base reaction was useful and could effectively enhance the photocatalytic hydrogen evolution reaction. This is a general facile solvothermal method because it can be used for the grafting of other types of functional aromatic organic dyes onto g-C3N4.

This work presents a theoretical study about the interaction between the carbon nanotubes (CNT), boron nitride nanotubes (BNNT) and gallium nitride nanotubes (GaNNT) with the pollutant diamines: cadaverine and putrescine, using Density Functional Theory (DFT) implemented in the SIESTA software. For this purpose, we analyzed the structural, energetic and electronic properties of the (10,0) nanotubes with the cadaverine and putrescine adsorbed on their external surfaces. From the results, two important conclusions were inferred: i) CNT and BNNT interacted with both molecules through a moderate adsorption process, making spontaneous desorption not so difficult; ii) GaNNT interacted very strongly with both molecules through a chemical adsorption process, which difficults the desorption process. Finally, the results are promising for the use of BNNT in environmental applications, such as pollutant sensors for detecting selectively cadaverine in presence of putrescine molecule.

A practical non-hazardous one-pot protocol for the synthesis of benzisothiazolones and benzisoselenazolones, involving magnetically retrievable nano-nickel ferrite catalyzed tandem annulation between 2-halobenzanilides and elemental S₈ or Se.