Journal of The Chinese Chemical Society最新文献

Focus of the figure: Naturally occurring xanthohumol O (2) and related compounds (3 and 4) were synthesized successfully. The core structure of chalcone was synthesized by Claisen–Schmidt condensation from appropriate acetophenones and benzaldehydes. The synthetic xanthohumol O showed a strong anti-inflammatory effect with an EC₅₀ value of 0.79 μM. More details about this figure will be discussed by Dr. Ming-Jaw Don and his co-workers on pages 902–909 in this issue.

A large amount of SO₂ produced by large ships during fuel burning is a serious threat to people's health. It is urgently required to develop a method of detection with rapid response time and low detection limits. HPQRB has great fluorescent properties; it has a low detection limit and rapid response time. In this article, the detection mechanism of fluorescent probe HPQRB for HSO₃⁻ and the excited-state intramolecular proton transfer (ESIPT) process have been unveiled by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). HPQRB and HPQRB-HSO₃ both have planar structures in the ground state (S₀) and the first excited (S₁) state. Combining structural parameters and infrared vibrations, the hydrogen bond has been strengthened upon photoexcitation, providing the driving force for the ESIPT process. Orbital-weighted Fukui function and dual descriptor confirm that C₉ (shown in Figure 1) of HPQRB is the reaction site of HSO₃⁻ attacking. The calculated absorption and emission are consistent with the experiment, indicating that our calculations are reliable. By building potential energy curves (PECs), we find that the high reaction barrier from keto form to enol form in the S₁ state is the reason why HPQRB-HSO₃ only has one emission peak. Natural transition orbitals (NTOs) and hole–electron show that both HPQRB and HPQRB-HSO₃ are local excitation (LE) and exhibit ππ* properties. Compared with HPQRB, the conjugated structure of HPQRB-HSO₃ after Michael addition is disrupted, causing a weaker electron transfer after photoexcitation, which leads to the blue shift of the emission peaks.

A series of [5]phenacene (picene) incorporating (triisopropylsilyl)ethynyl functionality, TSEPs, was conveniently synthesized via a Mallory photoreaction–Sonogashira reaction sequence. For the Sonogashira reaction of 1-bromopicene, an unexpected 14-(triisopropylsilyl)ethynyl-substituted product, 14-TSEP, was afforded along with the normal Sonogashira-reaction product, 1-TSEP. The UV–Vis and fluorescence spectra of TSEPs were observed to reveal the effects of the position and number of ethynyl functionalities on the electronic features of TSEPs. All TSEPs investigated displayed a small absorption band (¹L_b) in the 382–398 nm wavelength region, and a larger one (¹L_a) in the 325–371 nm wavelength region. The shift of the absorption bands was more pronounced for the ¹L_a band compared with the ¹L_b band. Within the TSEP series, a fluorescence quantum yield of 5,8-TSEP (Φ_F = 0.25) was the largest and that of 2-TSEP was the smallest (0.08). The spectral features of the picene chromophore were found to be manipulated by the position and number of TIPS substituents.

A novel C₃-symmetric organogelator based on a tris(triazolylmethyl)benzene core functionalized with three long-chain pyridine-2,6-dicarboxamide branches has been successfully synthesized using a straightforward and modular “click chemistry” approach. This design enables efficient molecular construction while allowing for precise control over supramolecular functionality. The resulting molecule exhibits robust self-assembly behavior, driven by a synergistic interplay of noncovalent interactions, including intermolecular hydrogen bonding, π–π stacking between aromatic moieties, and van der Waals forces among the flexible alkoxyl chains. Upon self-organization in suitable solvents, the organogelator forms a three-dimensional network that immobilizes the liquid phase, resulting in gelation. Advanced imaging techniques such as atomic force microscopy and fluorescence microscopy reveal the formation of intricate supramolecular nanostructures, including lemniscate (figure-eight) and toroidal morphologies, underscoring the unique self-assembly capabilities associated with the compound 1. These findings not only demonstrate the potential of triazole-linked aromatic cores integrated with long-chain pyridine-2,6-dicarboxamides as versatile scaffolds for supramolecular gelators but also highlight their promise for applications in nanomaterials, soft matter, and functional supramolecular architectures.

In this work, a ternary composite electrode consisting of reduced graphene oxide (rGO), copper oxide (Cu₂O), and molybdenum oxide (MoO₂) was developed using a feasible and cost-effective hydrothermal method. The rGO/Cu₂O/MoO₂ ternary composite electrodes exhibited superior electrochemical performance compared to individual and binary composite electrodes. Cyclic voltammetry results demonstrated that the prepared composite electrodes could detect glucose concentrations linearly in the range of 0.1 to 0.8 mM, achieving a high sensitivity of 7474.29 μA mM⁻¹ cm⁻² and a detection limit of 1.30 μM. Additionally, the composites exhibited good reproducibility, with a Relative Standard Deviation (RSD) of 2.75%, and excellent stability, retaining 99% of their performance over time. The outstanding performance of the ternary composites is attributed to the synergistic effects of Cu and Mo metal oxides, along with the high surface area of the rGO sheets, making rGO/Cu₂O/MoO₂ a promising composite material for non-invasive glucose-sensing applications.

Galvanic displacement in an ionic liquid was utilized to deposit palladium (Pd) or platinum (Pt) onto a copper (Cu) surface. Compared to water and conventional organic solvents, the relatively high viscosity of ionic liquids offers a distinct advantage in controlling the modification process, as the reduced mass transfer leads to a slower and more manageable displacement rate. This control is crucial; excessive deposition of Pd or Pt on the Cu surface can result in diminished, rather than enhanced, electrochemical nitrate reduction activity. Cu surfaces modified with an appropriate amount of Pd or Pt exhibited improved electrochemical performance toward both nitrate (NO₃⁻) and nitrite (NO₂⁻) reduction. This enhancement is likely attributed to the increased porosity induced during the galvanic displacement process, as well as synergistic effects between Pd/Pt and Cu. Overall, galvanic displacement in ionic liquids represents a practical and effective strategy for the synthesis of Cu-based electrocatalysts for electrochemical nitrate reduction.

We herein report the design, synthesis, and characterization of novel dye molecules based on bis-Pd(II) complexes of bis(TIPS-ethynyl)-substituted doubly N-confused hexaphyrins (t-Pd₂-3 and c-Pd₂-3). These complexes exhibit distinct absorption and emission properties in a sub-channel of the second near-infrared (NIR-IIb) region. The anisotropic π-extended derivative, t-Pd₂-3, which features two silyl-protected ethynyl groups at the 5,20-positions, has a rigid, rectangular hexapyrrolic core that provides distinct NNNC coordination environments. The resulting bis-Pd(II) complex, t-Pd₂-3, exhibits characteristic molecular orbital mixing in the S₀ → S₁ transition—specifically in the Q-state band—with reduced configuration interaction between the HOMO and LUMO, which leads to enhanced NIR-IIb absorption and emission beyond 1500 nm. This pronounced Q-band absorption contributes to the generation of NIR-IIb photoacoustic (PA) signals, rendering it a potential PA contrast agent. The current study offers new insights into the design of stable, expanded porphyrinic dyes for applications in photon-to-thermal therapy and imaging.

Stainless steel is widely employed as a substrate for electrocatalytic water splitting due to its low cost, high availability, and ease of fabrication. However, its intrinsic oxygen evolution reaction (OER) activity remains nonoptimal, particularly under high current densities. In this study, a simple and energy-efficient low-temperature (90°C) liquid-phase sulfidation method was applied for the surface modification of 316L stainless steel mesh (SSM), which was subsequently transformed into sulfidation SSM (S-SSM) to enhance the OER activity. The S-SSM was confirmed by X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses, and the resulting material exhibited excellent OER performance, which the potential required to reach current densities of 10, 100, and 1000 mAcm⁻² were 1.475, 1.523, and 1.603 V, respectively. This work demonstrates that through a simple and low-energy surface treatment, SSM can be easily transformed into S-SSM as a high-performance OER catalyst, showing the great prospect of low-cost and scalable production toward the realization of electrocatalytic water splitting.

Chiral helicene radicals having a combination of molecular chirality and unpaired electron spin(s) are of increasing interest from both fundamental science and technological fields. We have synthesized a helicene compound, wherein a 1,1′-biazulene skeleton is fused with an isobenzopyrrole unit that has bulky mesityl groups for steric protection. The final cyclization reaction for the target compound was accomplished very efficiently by using a microflow method. The helical structure was confirmed by X-ray crystallography, and the optical resolution was achieved by HPLC with a chiral stationary phase. Upon one-electron oxidation of this compound, its cation radical was successfully produced with enough stability for isolation.