Latest ArticlesTwo-dimensional (2D) carbon nitride sheets (CNs) with atomically thin structures are regarded as one of the most promising materials for solar energy conversion. However, due to their substantially enlarged bandgap caused by the strong quantum size effect and their incomplete polymerisation with a large number of non-condensed surface amino groups, the practical applicability of CNs in photocatalysis is limited. In this study, CNs with broad visible-light absorption were synthesised using a 5-min fast thermal annealing. The removal of uncondensed amine groups reduces the bandgap of CNs from 3.06 eV to 2.60 eV, increasing their absorption of visible light. Interestingly, the CNs were distorted after annealing, which can differentiate the spatial positions of electrons and holes, enhancing the visible-light absorption efficiency. As a result, when exposed to visible light, the photocatalytic hydrogen production activity of atomically thin 2D CNs rose by 8.38 times. This research presents a dependable and speedy method for creating highly effective visible-light photocatalysts with narrowed bandgaps and improved visible-light absorption.
Understanding the relationship between structure and properties is critical to the development of solid-state luminescence materials with desired characteristics and performance optimization. In this work, we elaborately designed and synthesized a pair of mononuclear iridium(Ⅲ) complexes with similar structures but different degrees of cationization. [Ir2-f][2PF6] with two counterions is obtained by simple N-methylation of the ancillary ligand of [Ir1-f][PF6] which is a classic cationic iridium(Ⅲ) complex. Such a tiny modification results in tremendously different optical properties in dilute solutions and powders. [Ir1-f][PF6] exhibits weak light in solution but enhanced emission in solid-state as well as poly(methyl methacrylate) matrix, indicative of its aggregation-induced emission (AIE) activity. On the sharp contrary, [Ir2-f][2PF6] is an aggregation-caused quenching (ACQ) emitter showing strong emission in the isolated state but nearly nonemissive in aggregation states. Benefiting from the appealing characteristics of mechanochromic luminescence and AIE behavior, [Ir1-f][PF6] has been successfully applied in reversible re-writable data recording and cell imaging. These results might provide deep insights into AIE and ACQ phenomenon of iridium(Ⅲ) complexes and facilitate the development of phosphorescent materials with promising properties.
We report the photo-mediated 1,2-aryl migration of 2–chloro-1-arylpropanones to 2-arylpropionic acids using HCOONa as an acid scavenger. This pragmatically focused study obviates the multiple-step sequence in the industrially employed, ZnO-promoted rearrangement strategy, and offers rapid access to various 2-arylpropionic acids under environmentally friendly conditions. Furthermore, the successful transfer of this batch photochemistry to a continuous flow platform led to improved scalability and enabled the gram-scale synthesis of loxoprofen.
Biomass pyrolysis oil can be improved effectively by electrocatalytic hydrogenation (ECH). However, the unclear interactions among different components lead to low bio-oil upgrading efficiency in the conversion process. Herein, benzaldehyde and phenol, as common compounds in bio-oil, were chosen as model compounds. The interactions between the two components were explored in the ECH process by combining experiments and theoretical calculations. Results showed that phenol could accelerate the conversion of benzaldehyde in the ECH. The selectivity of benzyl alcohol was increased from 60.9% of unadded phenol to 99.1% with 30 mmol/L phenol concentration at 5 h. Benzaldehyde inhibited the ECH of phenol. In the presence of benzaldehyde, the conversion rate of phenol was below 10.0% with no cyclohexanone and cyclohexanol formation at 5 h. The density functional theory (DFT) calculations revealed that the phenol could promote the adsorption of benzaldehyde and facilitate the targeted conversion of benzaldehyde on the active site by lowering the reaction energy barrier. The research on the interaction between phenol and benzaldehyde in the ECH provides a theoretical basis for the application of ECH in practical bio-oil upgrading.
Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting. Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery. Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools. Synthetic host-guest pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity, easy modification, and high chemo-selectivity. Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting. In order to further promote the development of host-guest pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages; next, we summarize the recent research progress in this area. The future perspectives and limitations of these unique tools will be discussed. This review will provide a systemic overview of the development of synthetic host-guest pairs as novel bioorthogonal tools for pre-targeting, and may serve as a "go for" resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.
Predictive modeling of photocatalytic NO removal is highly desirable for efficient air pollution abatement. However, great challenges remain in precisely predicting photocatalytic performance and understanding interactions of diverse features in the catalytic systems. Herein, a dataset of g-C3N4-based catalysts with 255 data points was collected from peer-reviewed publications and machine learning (ML) model was proposed to predict the NO removal rate. The result shows that the Gradient Boosting Decision Tree (GBDT) demonstrated the greatest prediction accuracy with R2 of 0.999 and 0.907 on the training and test data, respectively. The SHAP value and feature importance analysis revealed that the empirical categories for NO removal rate, in the order of importance, were catalyst characteristics > reaction process > preparation conditions. Moreover, the partial dependence plots broke the ML black box to further quantify the marginal contributions of the input features (e.g., doping ratio, flow rate, and pore volume) to the model output outcomes. This ML approach presents a pure data-driven, interpretable framework, which provides new insights into the influence of catalyst characteristics, reaction process, and preparation conditions on NO removal.
Remodeling tumor microenvironment (TME) is a very promising and effective strategy to enhance the effects of chemotherapy, photodynamic therapy, and immunotherapy. Normalization of tumor vasculature as well as depletion of glutathione (GSH) can improve the TME. Here, we developed a novel therapeutic nanoparticle functional enzyme ultra QDAU5 nanoparticles (FEUQ Nps) based on a fluorescence-on and releasable strategy by combining a vascular normalization inducer, a GSH depleting agent, and an activated fluorophore. In which the cleavage of disulfide bonds releases active molecules that induce vascular normalization and improve the hypoxic microenvironment. In addition, it may deplete GSH in cancer cells, thus inducing the production of reactive oxygen species (ROS) and lipid peroxide (LPO) and promoting iron toxicity. It may also lead to endoplasmic stress and release of calmodulin, which activates the immune system. Meanwhile, quenched fluorophores are turned on in the presence of galactosidase (GLU) for tumor-specific labeling. In summary, we developed novel therapeutic agent nanoparticles with the function of vascular normalization inducers to achieve specific labeling of hepatocellular carcinoma while exerting efficient antitumor effects in vivo.
Multifunctional molecules with both optical signal and pharmacological activity play an important role in drug development, disease diagnosis, and basic theoretical research. Aminopeptidase N (APN), as a representative tumor biomarker with anti-tumor potential, still lacks a high-precision theranostic probe specifically targeting it. In this study, a novel quaternity design strategy for APN theranostic probe was developed. This proposed strategy utilizes advanced machine learning and molecular dynamics simulations, and cleverly employs the strategy of conformation-induced fluorescence recovery to achieve multi-objective optimization and integration of functional fragments. Through this strategy, a unique "Off–On" theranostic probe, ABTP-DPTB, was ingeniously constructed to light up APN through fluorescence restoration, relying on conformation-induced effects and solvent restriction. Differ from the common diagnostic probes, the intelligent design with non-substrated linkage makes ABTP-DPTB for long-term in-situ imaging. The fabricated probe was used for detecting and inhibiting APN in various environments, with a better in vitro inhibitory than golden-standard drug bestatin.
An additive-free and environmentally friendly strategy has been realized for the construction of S-substituted isothioureas through visible-light-induced multicomponent reaction starting from α-diazoesters, aryl isothiocyanates, amines and cyclic ethers. This methodology features simple operation, mild reaction conditions, favorable functional group tolerance, easily available starting materials and high efficiency.
Bridged polycyclic lactams are important structural units in organic functional materials, natural products, and pharmaceuticals. A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1, 4-dien-3-ones. Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of BuOK in commercially available EtOH solvent at 60 ℃. Notably, the simple reactions can be run on a gram scale. Mechanistically, bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.
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