Journal of The Chinese Chemical Society最新文献

Amidst the global endeavor toward sustainable energy sources, photocatalysis appears as a promising gateway toward the production of solar fuels, in particular hydrogen. Hydrogen is currently a crucial reagent for vital industries such as petrol desulfurization, iron reduction and ammonia production, so the decarbonization of its production is a major challenge. CuMnO₂ (CMO), a p-type semiconductor, has been shown to enhance the efficiency of catalysts such as TiO₂ for the photoelectrocatalytic water splitting reaction. However, since pure CMO thin films have never been reported, its potential and limitations remain elusive. We used spray pyrolysis as a low-cost synthesis technique to simplify and accelerate the synthesis of CMO thin films directly on FTO substrates. CMO prepared in this manner exhibits activity toward photoeletrocatalytic water splitting and O₂ reduction. The activity has been found to be highly dependent on synthesis conditions, especially on the ratio and volume of precursors.

Bioactive peptides have been emerging as drug candidates with increasing importance in the last few decades. In this study, to evaluate the anticancer and antiviral properties of EER (Glu-Glu-Arg), EPR (Glu-Pro-Arg), and PRP (Pro-Arg-Pro) tripeptides, firstly their conformation preferences were searched, and the most stable optimized structure of each tripeptide was determined, using the molecular mechanics force field (MMFF) method and the Spartan06 program. Afterwards, each tripeptide was docked to SARS-CoV-2 spike protein receptor-binding domain (6M0J), SARS-CoV-2 main protease (6M03, 6LU7), spike glycoprotein (6VXX), DNA (1BNA), integrins (4WK0, 3ZDX, 1JV2) and epidermal growth factor receptor tyrosine kinase (4HJO). Moreover, molecular dynamics (MD) simulations were performed to validate the stability of the EER, EPR and PRP tripeptides docked to SARS-CoV-2 main protease, M^Pro (6M03) and epidermal growth factor receptor tyrosine kinase (4HJO) within 100 ns time scale and ligand-receptor interactions were evaluated. The metrics root-mean-square deviation, root-mean-square fluctuation, intermolecular hydrogen bonding, and radius of gyration revealed that the EER, EPR, and PRP tripeptides form energetically stable complexes with the target proteins. The binding free energies were calculated by the combination of Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) and Molecular Mechanics/Poisson-Boltzmann Surface Area (MM-PBSA) methods (MM/PB(GB)SA). Principal Component Analysis on MD data was performed to evaluate the energy and structural information of the tripeptide-protein complexes. Additionally, in-silico structure-based pharmacological predictions were made and the anticancer and antibacterial activities of the tripeptides were predicted.

Hg²⁺ is one of the most toxic heavy metals, posing a serious threat to the human body and the environmental ecosystem. In order to detect Hg²⁺ rapidly, accurately, and sensitively, a kind of boron, nitrogen, and sulfur co-doped carbon dots (B,N,S-CDs) were synthesized by a simple, economical, and direct hydrothermal method. The average size of the prepared B,N,S-CDs is 2.7 ± 0.7 nm, and the high photoluminescence quantum yield is 67.6%. Furthermore, due to the efficient quenching effect of Hg²⁺, such B,N,S-CDs are considered to serve as an efficient fluorescence sensing platform for label-free and sensitive detection of Hg²⁺ with a detection limit of 72 nM. The selectivity experiments reveal that the B,N,S-CDs are selective and specific for Hg²⁺ even in the presence of other interfering substances. Most importantly, the Hg²⁺ sensing platform based on B,N,S-CDs can be successfully applied to the determination of Hg²⁺ in tap water and real lake water samples. This stable and inexpensive carbon material exhibits excellent sensitivity and selectivity, potentially suitable for Hg²⁺ monitoring in environmental applications.

Motivated by the captivating allure of exquisitely regulated characteristics exhibited by 2-(2-hydroxyphenyl)-benzoxazole and its derivatives in the domains of photochemistry and photophysics, our current endeavor primarily focuses on delving into the intricacies of photo-induced excited state reactions for derivatives of 2,5-bis(benzoxazol-2-yl)-thiophene-3,4-diol (BTD). Given the profound impact of chalcogen element doping, our primary focus lies in investigating the excited state behaviors of BTD-O, BTD-S, and BTD-Se fluorophores. Through simulations encompassing variations in geometry and vertical excitation charge reorganization, we unveil atomic-electronegativity-dependent hydrogen bonding interactions and photoexcitation-induced charge recombination that can significantly augment the intramolecular double proton transfer (ESDPT) reaction in the excited state for BTD-O, BTD-S, and BTD-Se fluorophores. By constructing potential energy surfaces and identifying transition state forms, we elucidate the ultrafast stepwise ESDPT mechanism facilitated by the low potential barriers. Moreover, we rigorously validate the chalcogen atomic electronegativity-driven regulation of the stepwise ESDPT mechanism. We sincerely anticipate that manipulating solvent polarity will pave the way for groundbreaking advancements in luminescent materials.

Lead, a prevalent heavy metal, poses significant risks to human health through various exposure pathways. Herein, we propose an extremely sensitive assay toward lead ion (Pb²⁺) using gold nanorods (GNRs) as probes based on its catalytic activity on etching gold in the presence of 2-mercaptoethanol and sodium thiosulfate. In the presence of Pb²⁺, etching predominantly occurs at the two ends of GNRs, leading to the reduction of aspect ratio and the corresponding blueshift of the localized surface plasmon resonance (LSPR). With increasing Pb²⁺ concentration over the range of 0–50 μM, the color of GNR solution lightens, ultimately becoming colorless. The wavelength shift (Δλ) of LSPR is highly dependent on Pb²⁺ concentration, with a linear regression equation of Δλ = 10.05ln[Pb²⁺] + 9.59 and an R² = 0.995. The assay demonstrates high selectivity for Pb²⁺ over other potentially interfering ions such as Cu²⁺ because of its special catalytic activity in the etching of GNRs and the complexing ability of 2-mercaptoethanol and sodium thiosulfate. Validation of the assay was accomplished by analyzing several forest-derived food samples, affirming the accuracy in real-world scenarios. The assay we developed holds promise for many applications in environmental protection and food safety.

In this work, the effects of different functional groups on the excited-state intramolecular proton transfer behavior and fluorescent features of 3-hydroxy-2-(naphthalen-2-yl)-4H-chromen-4-one (HFN) are explored in detail. Three new compounds (HFN-1, HFN-2, and HFN-3) are designed based on the HFN by introducing the electron-donating groups (–NH₂, –N(CH₃)₂). The mainly geometrical parameters of optimized configuration showed that the intramolecular hydrogen bonds of the studied compounds are enhanced in the excited (S₁) state, confirming by the ground (S₀) and excited states infrared spectra, electron densities and reduced density gradient isosurfaces. The S₀ → S₁ transitions of HFN derivatives are dominated by ππ* charge transfer transition. The introduction of electron-donating group (–NH₂, –N(CH₃)₂) weakens the intramolecular hydrogen bond, increases the excited-state intramolecular proton transfer barrier and red-shifts the absorption/fluorescence peak. The coexistence of –NH₂ and –N(CH₃)₂ make the absorption and fluorescence wavelengths of HFN-1/HFN-2 red-shift/blue-shift.

As an important reactive oxygen species (ROS) signal molecule in plant physiological regulation, H₂O₂ maintains cellular homeostasis through concentration regulation. It is worth paying attention to the concentration imbalance of H₂O₂ caused by various stresses, resulting in programed cell death or even developmental arrest in plants. To accurately quantify alterations in H₂O₂ concentration induced by these stress factors, and deeply understand the H₂O₂-related physiological processes, a highly efficient hybrid electrode material of thionine@Ti₃C₂T_x (Th@MXene) composite was developed. MXene nanosheets not only performed as carriers with high specific surface area for loading Th but also contributed to the enhancement of electrical conductivity. Meanwhile, Th was uniformly loaded on the MXene surface, facilitating electron transport from the analyte to the modified electrode. Under the optimal detection conditions, the sensing electrode (Th@MXene/GCE) was employed to quantify H₂O₂ through Square-wave Voltammetry signals with a good linear relationship (correlation coefficient is 0.9997), and a wide calibration range of the sensor was 0.1 to 10,000 nM. Above all, the detection limit can be as low as 34 pM, demonstrating excellent sensitivity. Additionally, the sensor exhibited repeatability in real samples, demonstrating exceptional practicality.

In this work, we presented the results of density functional theory calculations for the static first hyperpolarizability for one representative push–pull π-conjugated molecule, 2-dimethylamino-7-nitrofluorene, in six organic solvents (p-dioxane, chloroform, tetrahydrofuran, acetone, acetonitrile, and dimethylsulfoxide) spanning a large range of dielectric constant. The finite-field formalism was used to calculate the longitudinal component of the static first hyperpolarizability. The solvent effect was calculated using two distinct polarizable continuum solvation models: the linear response and the state-specific polarizable continuum models. The calculations demonstrated the existence of solvation model effects on the property of interest, which warranted further analysis. The two-level model was then employed to illustrate the impact of solvation model. Our findings suggested that the state-specific polarizable continuum model gave a decrease of the dipole moment of the excited state in high polarity solvent for a bathochromic molecule whose excited state should have a larger polarization than its ground state.

This work designed and synthesized the first organic fluorescent sensor for lutein in aqueous solutions based on blue to yellow fluorescence change of thiosemicarbazide-bridged bis-tetraphenylene (Bis-TPE). By condensing monohydroxy tetraphenylene derivatives with p-phenylene di-isothiocyanate, Bis-TPE was produced. A fluorescence spectrophotometer was used to scan the fluorescence emission spectra from 380 to 700 nm with 360 nm as the excitation wavelength. The fluorescence spectra showed that Bis-TPE exhibited high selective sensing ability for lutein in aqueous medium, and the fluorescence showed red-shift phenomenon with a limit of detection as low as 0.26 μM for lutein. The sensing mechanism was confirmed by mass spectrometry, infrared, and fluorescence Job's plots based on the 1:1 stoichiometric ratio of double hydrogen bonding. The successful application of Bis-TPE in sensing test strips means that Bis-TPE can achieve efficient detection of lutein in complex environments. As a result, an aggregation-induced luminescence-based lutein fluorescence sensor was constructed, which exhibited highly selective and sensitive sensing of lutein, and provided a new research idea for the object detection of such structures.