The advancement of multifunctional fluorescent probes for monitoring diverse environmental parameters is of paramount importance. In this study, we engineered dual-chromophore fluorescent probe, DBT, that responds to multiple stimuli by integrating functional groups with unique characteristics. Notably, the probe DBT exhibits pronounced bimodal emission under specific conditions, with its fluorescence shifting between red and blue in response to alterations in solvent composition, humidity levels, and temperature variations. Significantly, DBT facilitates the differentiation and visual identification of eight solvents, and permits the quantitative detection of trace water content in organic solvents. Additionally, it allows for the visual detection of gasoline. These findings herald the development of single-molecule fluorescent materials capable of responding to multiple stimulus, paving the way for simultaneous multi-stimuli detection and discrimination in various applications.

Excited-state intramolecular proton transfer (ESIPT) involves photochemical tautomerization between two excited states (E* and K*) via intramolecular proton transfer. Developing polymer photochromism based on the photochemical tautomerization of organic ESIPT molecules has been rarely reported. We report the ESIPT molecule HBT-2OH exhibits concentration-dependent photochromic behavior in a polyurethane (PU) network. At low concentrations, HBT-2OH primarily exists in the trans-enol configuration without intramolecular OH···N hydrogen bonds in PU, emitting blue fluorescence at ~464 nm (enol emission). Upon UV irradiation, the dihedral angle between the proton donor and acceptor twists to form an intramolecular OH···N H-bond, converting trans-enol to cis-enol and resulting in ESIPT with pale yellow fluorescence at ~603 nm (keto emission). The photochromic effect of HBT-2OH@PU diminishes at high concentrations due to that aggregation favors the cis-enol form. Control molecules HBT, HBO-2OH, and HBI-2OH show no photochromism in PU, confirming that ethanolyl branches and intramolecular OH···S hydrogen bonds stabilize the trans-enol configuration of HBT-2OH. Incorporating these molecules into PMMA and PCL networks demonstrates that increased free volume and smaller aggregates enhance photochromism by reducing resistance to dihedral angle twisting. Density functional theory (DFT) calculations further confirm stable intramolecular heteroatomic hydrogen bonds (OH···S) exist in HBT-2OH. This study offers new theoretical insights and opens avenues for research on polymer based photochromic materials.

The nickel-rich layered ternary cathode material (NCM) has been extensively studied due to its high specific capacity and low cost. Nevertheless, with the increase of Ni content, the unstable structure of NCM material has gradually become prominent. Residual alkali on the surface and Li⁺/Ni²⁺ mixing before cycling, phase change, transition metal ions dissolution, microcracking, and other issues during the cycle, are the primary causes for the fast capacity fading of Ni-rich materials. In this study, Sc³⁺ is doped into the LiNi_0.8Co_0.1Mn_0.1O₂ material, which has been demonstrated to impede the Li⁺/Ni²⁺ mixing, while simultaneously increasing the layer spacing. This results in the stabilization of the material structure and an enhancement of both the cycling stability and the rate performance. Notably, single-particle force testing and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging further demonstrate reduced stress accumulation and mitigated chemo-mechanical failure. This study underscores the efficacy of a minor addition of multifunctional rare-earth doping in enhancing the chemo-mechanical stability of Ni-rich cathodes, offering a straightforward and comprehensive solution to optimize the design and performance of energy storage cathodes.

The N–H methylsulfoxidation of sulfoximines using DMSO as a methylsulfinyl source, induced by electrochemistry, has been developed. This method is the first example of an electrochemical reaction in which DMSO serves as a methylsulfinyl source. Unlike previous electrochemical reactions involving DMSO as a substrate, which exclusively proceed via radical mechanisms, this reaction follows an S-cation pathway. A wide range of N-methylsulfinyl sulfoximines were successfully obtained.

Herein, we report a photo-induced, metal-/additive-free protocol for the difluoromethylation of N-heteroaromatics with [bis(difluoroacetoxy)iodo]benzene as the difluoromethylation reagent. The protocol affords difluoromethylated N-heteroaromatics in moderate to good yield (up to 91%). The transformation is compatible with a wide range of substrates and has good tolerance towards various functional groups. Moreover, the synthetic value of this method is further demonstrated by applications in gram-scale synthesis and the late-stage functionalization of biologically important molecules.

We have developed a series of 1-methylpyridine-2(1H)-thione (MPT) analogues to be used as organocatalysts. The MPT catalysts are easily prepared and bench-stable. In our previous work, we found that the ground-state MPT catalyst could act as a nucleophile to generate primary radicals via an S_N2 pathway. However, this reaction was limited to benzyl radicals. Herein, we reported a new catalytic property of the MPT catalyst. The photoexcited MPT catalyst (E(MPT^·+/MPT*) = –1.60 V vs. Ag/AgCl in MeCN) could reduce NHPI esters through a single electron transfer process. Various carbon radicals, including benzyl radical, as well as primary, secondary and tertiary alkyl radicals, could be generated easily. Notably, amino acids, peptide, pharmaceuticals, and other biologically active molecules could be modified by using this methodology showing the potential synthetic utility of this method.

The development of sustainable and efficient catalytic systems for the formation C—C, C—N, C—O bonds is a fundamental goal in modern synthetic chemistry. We present a biomass-derived Cu/Chitosan-800 catalyst that facilitates a range of carbenoid insertion reactions into C—H, N—H, and O—H bonds. This catalyst demonstrates remarkable activity, enabling the functionalization of diverse substrates, including the late-stage modification of drug molecules with up to 95% yield and good recyclability. Our findings highlight the catalyst's potential in advancing environmentally friendly chemical transformations, offering a promising tool for pharmaceutical synthesis and organic synthesis.

N-Methylimidazole borane adducts were synthesized and their reactivities with different electrophiles after deprotonation were compared. Subsequently, we used the more stable and reactive imidazole adducts with B₃H₇, a multinuclear borane, to generate various C2, C2 benzyl, and C2,5-disubstituted imidazole adducts of B₃H₇ under mild reaction conditions. Some 2,5-disubstituted imidazole products are usually difficult to synthesize directly from imidazole molecules. Furthermore, the borane moiety of these adducts can be easily removed to obtain the corresponding imidazoles. The higher reactivity of the imidazole adducts of B₃H₇ compared to their corresponding imidazoles may be attributed to the σ-aromaticity of B₃H₇ or mediated by double hydrogen bonds.

Artemisieverolides A—G (1—7), seven unreported sesquiterpenoid trimers, were isolated from Artemisia sieversiana (Asteraceae), and elucidated by comprehensive spectral data and electronic circular dichroism (ECD) calculations. Compounds 1, 2, 4 and 6 were unambiguously determined by the single-crystal X-ray diffraction. Artemisieverolide A (1) was an unprecedented guaianolide sesquiterpenoid trimer featuring a rare 5/7/4/7/5 carbon skeleton biogenetically derived from [2+2] cycloaddition and a 2-methylbicyclo[2.2.1]-2-heptene ring through a Diels-Alder (D-A) reaction. Artemisieverolides B—G (2—7) were guaianolide sesquiterpenoid trimers generated by two D-A reactions. Compounds 3, 4, and 5 exhibited inhibitory activities on the proliferation of HSC-LX-2 with the IC₅₀ values of 52.6, 58.4, and 54.8 μmol/L, and were about 3 folds more active than silybin (IC₅₀ = 149.4 μmol/L). Furthermore, compounds 2 and 7 suppressed the expression of collagen I in TGF-β1-stimulated HSC-LX-2.

A novel carboanion relay enabled [1 + 2 + 2 + 1] cascade cyclization reaction utilizing rarely used isatin-derived β-silylcarbinols and aryl methyl ketones as readily available starting materials has been developed, endowing a powerful platform for the streamline synthesis of cyclohexane-tethered bispirooxindoles in decent yields with high diastereoselectivities. This protocol was realized by merging triple Michael additions and C—C bond cleavage using Cs₂CO₃ as a robust promotor under transition metal-free conditions. The practicability of this method is demonstrated by its simple operation, broad substrate scope as well as easy scale-up.

Allenylboronates are valuable synthetic building blocks and have garnered significant interest. However, their 1,3-diboyl substituted analogs have not been reported. Herein, we disclosed a novel method for creating 1,3-diboyl allenes from gem-iododiboron compounds and alkynyl Grignard reagents. The starting materials are initially converted into the corresponding propargylic gem-bis(boronates), which then undergo an intermolecular boryl group transfer to afford 1,3-diboyl allenes, as confirmed by mechanistic studies. This method features good tolerance to steric hindrance and is compatible with a wide variety of functional groups.

Metal-organic frameworks (MOFs) contain ordered metal nodes, organic linkers, and guest species, which generally determine their properties respectively and/or synergistically. Guest species play a crucial role in maintaining charge balance and structural stability of MOFs. In addition to metal nodes and organic linkers, the type and distribution of guests can significantly influence the properties of MOFs, such as optics, magnetism, chirality, and catalysis. Understanding the role of guests to the properties of MOFs remains great challenge due to the complex chemical and electronic structures of MOFs. Recently, progresses on guest-dependent properties of MOFs have been reported, which not only advanced our knowledge of host-guest interactions and energy transfer mechanisms but also led to intriguing applications such as luminescent sensors, tunable magnetic materials, enantioselective materials, and catalysts. Crucially, the interactions between the host and guest can be finely tuned by altering the type and amount of guests without changing the core framework, allowing for precise regulation of targeted properties. In this review, we will explore how guest-induced variations impact the optic, magnetic, chiral, and catalytic properties of MOFs, followed by an examination of the synergistic effects between hosts and guests, which is highly important for the development of advanced functional materials.