Latest ArticlesRegioselevtive functionalization of perylene diimides (PDIs) at bay area often requires multistep synthesis and strenuous recrystallization. Direct bromination of perylene diimides only afford the 1, 6 and 1, 7-regioisomers. More importantly, the 1, 6-dibromo regioisomers could only be separated by preparative HPLC. Herein, we report a promising strategy for constructing Janus backbone of BN-doped perylene diimide derivatives. This Janus-type configuration results in the unique regioselective functionalization of BN-JPDIs, which yields exclusively the 1, 6-regioisomers. Further investigation shows that the Janus-type configuration leads to a net dipole moment of 1.94 D and intramolecular charge transfer, which causes substantial changes on the optoelectronic properties. Moreover, the single crystal organic field-effect transistors based on BN-JPDIs exhibit electron mobilities up to 0.57 cm2 V−1 s−1, showcasing their potential as versatile building block towards high-performance n-type organic semiconductors.
Fluorescence imaging-guided photodynamic therapy holds great promise for application in precise cancer diagnosis and treatment, which has motivated high requirements for phototheranostic agents. However, current photosensitizers (PSs) generally face limitations such as short emission wavelength and inadequate reactive oxygen species (ROS) production. Aggregation-caused quenching issue also hinders the phototheranostic efficiency of PSs. Herein, the π-bridge modulation strategy is proposed to construct ionic PSs with enhanced bioimaging and therapeutic outcomes. Two donor-π-acceptor (D-π-A) molecules TPCPY and TFCPY were obtained by incorporating phenyl and furan units as π-bridge, respectively. Both PSs feature aggregation-induced near-infrared emission. Under light irradiation, TPCPY and TFCPY can produce both type Ⅰ and Ⅱ ROS. Introducing furan ring in TFCPY enhances the ROS generation capacity by type Ⅰ photosensitization process, which is consistent with the reduced energy gap between singlet and triplet states from theoretical calculation. Furthermore, TFCPY can achieve quick cellular uptake, accumulate in mitochondria, and then efficiently kill cancer cells, which is superior to TPCPY. Consequently, TFCPY exhibited good antitumor outcomes and excellent in vivo fluorescence imaging ability. This work provides an efficient molecular engineering of introducing heterocycles into the D-π-A skeleton to develop high-performance PSs with both type Ⅰ and Ⅱ ROS generation.
Carbon dots (CDs)-based composites have shown impressive performance in fields of information encryption and sensing, however, a great challenge is to simultaneously implement multi-mode luminescence and room-temperature phosphorescence (RTP) detection in single system due to the formidable synthesis. Herein, a multifunctional composite of Eu&CDs@pRHO has been designed by co-assembly strategy and prepared via a facile calcination and impregnation treatment. Eu&CDs@pRHO exhibits intense fluorescence (FL) and RTP coming from two individual luminous centers, Eu3+ in the free pores and CDs in the interrupted structure of RHO zeolite. Unique four-mode color outputs including pink (Eu3+, ex. 254 nm), light violet (CDs, ex. 365 nm), blue (CDs, 254 nm off), and green (CDs, 365 nm off) could be realized, on the basis of it, a preliminary application of advanced information encoding has been demonstrated. Given the free pores of matrix and stable RTP in water of confined CDs, a visual RTP detection of Fe3+ ions is achieved with the detection limit as low as 9.8 µmol/L. This work has opened up a new perspective for the strategic amalgamation of luminous guests with porous zeolite to construct the advanced functional materials.
Electrochemical nitrate reduction (NO3RR) offers a promising avenue for treating nitrate-contaminated water and recovering ammonia (NH3), yet the complexities of direct electron transfer (DET) and hydrogen atom transfer (HAT) mechanisms crucial for efficiency remain elusive. This study bridges the gap with a combined experimental and theoretical approach, elucidating the impact of catalyst structure on NO3RR pathways. We discover that catalysts favoring strong NO3− adsorption and efficient water dissociation were more inclined towards DET, enhancing denitrification. The Fe@Fe3O4/FF cathode, leveraging the synergistic interplay between metallic Fe and Fe3O4, excelled in NO3RR via DET, achieving an NH3 yield of 0.28 mmol h−1 cm−2 and a Faradaic efficiency of 95.7% for NH3 at -1.6 V (vs. SCE), with minimal nitrite accumulation at 100 mmol/L nitrate. Conversely, the Fe/FF and Fe3O4/CC cathodes showed reduced NH3 production and increased nitrite levels, attributed to the lack of Fe3O4 and metallic Fe, respectively, resulting in a dominant HAT mechanism. Moreover, Fe@Fe3O4/FF facilitated complete denitrification in real wastewater treatment by harnessing Cl− for electrochemically mediated breakpoint chlorination. This research not only deepens our understanding of NO3RR mechanisms but also paves the way for designing superior nitrate reduction catalysts.
Studies widely acknowledge the enhancement of permanganate (Mn(Ⅶ)) oxidation of organic contaminants by coexisting matrices in water. This study investigated the positive influence of Mn(Ⅱ), a common soluble metal ion, on the removal of trace organic pollutants by Mn(Ⅶ). Results showed that introducing 20 µmol/L Mn(Ⅱ) at pH 5.0 accelerated trace organic pollutant removal by promoting colloidal MnO2 formation. UV−vis spectrum, quenching, and probe experiments confirmed role of MnO2 in sulfamethoxazole (SMX) oxidation, with Mn(Ⅲ) playing a predominant role. Meanwhile, in situ-generated MnO2 facilitated Mn(Ⅶ)* formation, enhancing oxidation performance, as indicated by Raman spectroscopy and electrochemical analysis. Eleven transformation products (TPs) of SMX in the Mn(Ⅶ)/Mn(Ⅱ) process were detected by UPLC-QTOF-MS/MS. Subsequently, the reaction pathways of SMX were elucidated through Fukui index analysis and the identification of TPs. Additionally, toxicity simulations with Toxicity Estimation Software Tool (T.E.S.T.) software revealed significantly lower cytotoxicity of TPs of SMX compared to the parent compound. This study unveils an effective strategy to enhance Mn(Ⅶ)-mediated degradation of organic pollutants in water, elucidating Mn(Ⅱ)-induced Mn(Ⅶ) activation mechanisms.
Metal halide perovskite nanocrystals (MHP NCs) are of great candidates in photocatalytic applications due to their extreme light utilization efficiency. However, the instability towards humid environment severely restrict their practical application. Herein, the CsPbBr3/CsPb2Br5 heteronanocrystals (HNCs) were successfully encapsulated into ZIF-8 through a thermal injection method via controlling the molar ratio of Cs+/Pb2+. The surface of ZIF-8 was then modified with hydrophobic copolymer of poly(methyl methacrylate) (PMMA) to improve the water stability. Benefiting from the intimate interfacial interaction and staggered energy band structure, the type-Ⅱ heterojunction of CsPbBr3/CsPb2Br5 guarantees efficient separation and migration of photogenerated electron/hole pairs. Meanwhile, the formation of Z-scheme heterojunction between ZIF-8 and CsPbBr3/CsPb2Br5 HNCs contributes to the adsorption and enrichment of pollutants, further accelerates the photocatalytic antibiotic degradation efficiency towards tetracycline hydrochloride (TCH) in aqueous solution. Nearly 87% of TCH (40 mg/L, 50 mL) was degraded by 40 mg catalyst within 100 min. This work offers a feasible approach in assembling high-performance MHP NCs-based efficient photocatalyst with expanding application in aqueous solution.
In the fight against bacterial infections, it is critical to effectively disrupt biofilms. However, disruption of biofilms becomes exceptionally difficult due to the low permeability of therapeutic agents. Herein, we present a self-propelled nanovesicle (PCL-PLG@CHX) strategy for eliminating biofilms and further expediting the healing of wounds. PCL-PLG@CHX is synthesized by assembling vesicles from amphiphilic polymers, which incorporate both poly-ε-caprolactone and guanidinated-poly-ε-lysine (PCL-PLG) and are infused with chlorhexidine (CHX). Upon application to sites of bacterial infection, PCL-PLG@CHX, abundant in guanidinium structures, effectively accumulates on the negatively charged surface of biofilms. It interacts with reactive oxygen species (ROS) within the biofilm, leading to nitric oxide (NO) production. The generated NO cannot only propel the nanovesicle to penetrate deeper into the biofilm, but also act as a signaling molecule to disperse the biofilm, working in conjunction with the subsequent release of CHX for an enhanced antibacterial impact. Following the eradication of bacteria, the residual guanidine component continues to produce small quantities of NO, facilitating angiogenesis and epithelial growth, thereby accelerating the healing of wounds. Together, our study shows that PCL-PLG@CHX utilizes the potential of guanidine moieties to efficiently break down biofilms and support tissue restoration, tackling the pivotal challenge of biofilm-related diseases.
A novel organocatalytic asymmetric approach to oxazoline derivatives that proceeds through Mannich/annulation reaction of N-acylimines with 3-chlorooxindoles is presented. This strategy provides an efficient and convenient method to access enantioenriched oxazolines such as valuable chiral S, N-oxazoline ligand as well as Ferrox ligand in high yields with excellent enantio– and diastereroselectivity. Furthermore, the optically active oxazoline products can be converted to valuable 1, 2-amino alcohols. More importantly, the synthetic utility of this transformation is demonstrated in the expeditious assembly of chiral Phox-type ligand, which shows excellent catalytic activities.
Herein, we report the design and synthesis of alternating donor-acceptor nanorings [3]C-NA and [4]C-NA, along with a reference linear molecule [3]L-NA, via electrochemical oxidation-induced reductive elimination of alkynyl platinum(Ⅱ) complexes. Unlike [3]L-NA, which exhibits charge defects at its end-groups, the cyclic structures of [3]C-NA and [4]C-NA facilitate enhanced electron delocalization, enabling efficient charge transfer in low-polarity toluene. In the polar solvent dichloromethane (DCM), the increased flexibility of [4]C-NA promotes intramolecular charge transfer and suppresses charge recombination. The observed faster intramolecular charge transfer and slower charge recombination rates in these nanoring acceptor materials suggest their potential for improving the power conversion efficiency of organic solar cells, providing valuable insights for the design of nanoring acceptor materials.
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is an attractive technology for the visualization of metabolite distributions in tissues. However, detection and identification of low-abundance or poorly ionized metabolites remains challenging. Although on-tissue chemical derivatization (OTCD) holds great promise for improving MALDI MS detection sensitivity and selectivity by modification of specific chemical groups, the available methods for subsequent metabolite annotation are limited. Herein, a laser-assisted chemical transfer (LACT)-based parallel OTCD strategy was established for visualizing and annotating carbonyl metabolites in murine brain tissues. Girard's T and Girard's P reagents were applied for parallel OTCD to generate the characteristic m/z pairs with a 19.969 Da mass shift (±0.020 Da tolerance) for rapid recognition of derivatized metabolites. The similarity of spatial distribution patterns of each m/z pair was further statistically evaluated to remove the ambiguous annotations due to the occurrence of interference compounds. As a result, 90 ion pairs were annotated as candidate carbonyl metabolites, 66 were previously known and 24 were potential unreported carbonyls. Furthermore, the spatial alterations of carbonyl metabolites in the ischemic rat brain were successfully visualized and characterized, including small molecule aldehydes and ketones, long-chain fatty aldehydes, and monosaccharides. This further emphasizes great potential of parallel OTCD strategy for efficient and confident molecular annotation of spatial submetabolomics data associated with brain diseases.
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