Journal of The Chinese Chemical Society最新文献

In the current study, microporous activated carbons (ACs) were synthesized from gum Arabic tree seed shells (GT) using a hydrothermal method, followed by activation of KOH (KOH to Biomass is 1:3) and carbonization at various temperatures. The resulting ACs were evaluated for their CO₂ adsorption capacity. Among all the prepared ACs, GTC-750 exhibited a high CO₂ uptake of 3.49 mmol/g at ambient conditions. This superior CO₂ adsorption performance was primarily attributed to its high microporous surface area (1195 m²/g), substantial micropore volume (0.79 cm³/g), narrow pore size (0.75 nm), and the existence of more abundant basic oxygen functional groups. The textural properties of the ACs were characterized by using various kinds of characterization techniques, such as N₂ adsorption–desorption, X-ray diffraction, Fourier-Transform Infrared Spectroscopy, X-ray photoelectron spectroscopy, Field Emission Scanning Electron Microscopy, Raman, and CHNS elemental analysis. Furthermore, the dynamic CO₂ adsorption behavior was evaluated using the Yoon-Nelson model, Bohr-Adams, and Thomas models. In addition to its high CO₂ uptake, GTC-750 demonstrated excellent recyclability during adsorption–desorption up to ten consecutive cycles.

In halide perovskites, the hole transport material determines the high charge transport properties. Therefore, highly efficient hole transport materials have been developed. On the other hand, the hole transport layer is sensitive to environmental conditions such as water and oxygen due to ionic treatments such as cation doping, and the issue of environmental durability has always been raised. Carbon materials are promising as new hole transport layers in halide perovskite materials because they are hydrophobic materials and have hole transport properties. Furthermore, various carbon materials can be used and are expected to be an alternative material for expensive hole transport layers. Leveraging the advantages of carbon materials, their combination with halide perovskites has been applied to fabricate air-stable solar cells. Moreover, the excellent water resistance of carbon materials has enabled the development of photoanodes that use halide perovskites as the photosensitive layer.

In this paper, silver-loaded Ag/P-C₃N₄ (Ag/PCN) was prepared by simple calcination, sol–gel, and hydrothermal synthesis methods. The morphological structures and photo-electro-chemical properties of the photocatalysts were characterized, and the results show that silver-loaded P-C₃N₄ (PCN) can effectively modify the energy band structure to enhance light absorption and greatly increase the conductivity to accelerate charge transfer and photo-generated carrier separation. The photocatalytic degradation of the organic pollutant MO showed that Ag/PCN achieved a 69.8% degradation rate in 120 min, which was 1.76 times higher than the pure PCN degradation rate (39.6%) and greatly enhanced the catalytic performance. The kinetic constant of catalyzed degradation by Ag/PCN (0.01319 min⁻¹) was 3.26 times higher than that of PCN (0.00405 min⁻¹). The enhanced catalytic performance is attributed to the fact that Ag doping can act as an electron-trapping agent to slow down the complexation of photogenerated electrons and holes, which further promotes the photoreduction performance of the photocatalytic polymer composites. This suggests that silver doping in PCN has the potential for the preparation of high-performance photocatalysts for organic pollutant removal.

Given the importance of oxygen group element doping in designing novel multifunctional organic molecules, herein, the classical 3,7-dihydroxy-4-oxo-2-phenyl-chroman-6-carbaldehyde (DOPCC) has been selected to probe into the related excited-state double-proton-transfer (ESDPT) mechanism. Three DOPCC chalcogen-doped derivatives (DOPCC, DOPCC-S, and DPOCC-Se) are considered in this work based on DFT and TDDFT methods. Analyses of principal geometrical variations, infrared (IR) spectral shifts, core-valence bifurcation (CVB), and electronic density ρ(r) within the framework of bond critical point (BCP) confirm that dual hydrogen bonds of DOPCC, DOPCC-S, and DPOCC-Se are enhanced by photo-induced excitation facilitating the ESDPT process. From the perspective of theoretical vertical excitation, the charge reorganization further confirms the tendency of the ESDPT reaction. The constructed potential energy surfaces (PESs) on the S1 state present three kinds of reaction paths, which all could support the ESDPT reactional behaviors. Comparing the reactional barriers among DOPCC, DOPCC-S, and DPOCC-Se derivatives, it could be found that DPOCC-Se should be the most favorable ESDPT reaction since it owns the lowest atomic electronegativity of chalcogen elements among DOPCC, DOPCC-S, and DPOCC-Se compounds. In brief, we present the atomic electronegativity of chalcogen elements regulating the ESDPT mechanism for DPOCC derivatives.

This study introduces a novel photoelectrochemical (PEC) biosensor for the detection of carbamazepine (CBZ), emphasizing the crucial role of precisely engineered multiwalled carbon nanotubes (MWCNTs). We transformed MWCNTs into short-cut MWCNTs (SC-MWCNTs) and graphene nanoribbons (GONRs) through controlled microwave and acid treatments and investigated the impact of these modifications on their electrochemical effective area (EA) and sensing performance. Transmission electron microscopy (TEM) was employed to characterize the resulting morphology and microstructure. Cyclic voltammetry (CV) measurements were conducted to assess the faradaic current response and quantify the EA of the synthesized materials. A strong correlation was observed between the EA and the CBZ sensing capabilities of the modified MWCNTs. Notably, the SC-MWCNT electrode treated for 2 h exhibited a remarkable 123% enhancement in PEC faradaic current compared with its electrochemical counterpart, demonstrating exceptional potential for highly sensitive PEC-based CBZ detection. This research highlights the significance of controlled modification of MWCNTs to optimize their EA for efficient and reliable CBZ monitoring, paving the way for advancements in carbon-based nanomaterial applications in PEC biosensor development and potentially reducing the reliance on extensive analyte testing during optimization.

Transition metal dichalcogenides are considered excellent cocatalysts for photocatalytic hydrogen production, and their cocatalytic activity depends on the number of layers and their contact state with the photocatalysts. Herein, monolayer WS₂ is generated by anchoring (NH₄)₂WS₄ nanocrystals on the CdS spheres with a continuous surface using a solid-state thermal reduction reaction. Due to the difference in Fermi levels between WS₂ and CdS, as well as their intimate contact, electrons from the conduction band of CdS swiftly flow to WS₂, achieving the spatioselective redistribution of carriers. The monolayer WS₂ shortens the longitudinal distance for electron migration from CdS to WS₂. Benefiting from the abundance of active edge sites on monolayer WS₂, the electrons enriched on WS₂ quickly capture and reduce protons to produce H₂. The H₂-generating rate of 0.75% WS₂/CdS is 6.95 mmol·g⁻¹·h⁻¹, with an AQE of 44.6% at λ = 420 nm. This work not only provides a facile method to anchor monolayer 2D materials on photocatalysts but also helps to understand the mechanism by which ultrathin cocatalysts enhance photocatalytic activity.

N⁶-adenosine methylation, or N⁶-methyladenosine (m6A), is the most prevalent and reversible modification event in mammalian messenger and noncoding RNAs, which can be dynamically regulated by writers, erasers, and readers in a context-dependent manner. The human YTHDF3 is a widely documented m6A reader that recognizes and interacts with m6A through its YTH domain, where the N⁶-methyl group of m6A is tightly captured by an aromatic cage defined by the YTH tryptophan residue triad Trp438–Trp492–Trp497. Considering that the aromatic cage has only a limited size that can accommodate only small atoms and moieties, we herein attempted to investigate the substitution effects of halogen modification of m6A's N⁶-methyl group (N⁶HCH₃) on YTHDF3 YTH recognition and binding. The N⁶-methyl group possesses three chemically equivalent hydrogens; each of which can be substituted by four halogens (X₁, X₂ and X₃ = F, Cl, Br and I). An integrated in silico-in vitro (iSiV) strategy was employed to examine the structural, energetic, and affinity effects of halogen modification on the binding of m6A mononucleotide to YTHDF3 YTH domain by systematically substituting one or more of the three N⁶-methyl hydrogens of m6A with four halogens, totally resulting in 34 N⁶-halomethyladenosine analogs (xm6A), including 4 single-, 10 double-, and 20 triple-substituted xm6A. It is revealed that the halogen modification can create favorable halogen–π interactions with the π-electron-rich aromatic cage, thus conferring affinity and specificity to the binding of xm6A to YTHDF3 YTH domain. However, multiple substitutions with bulky halogen atoms such as I would cause unfavorable steric overlaps and clashes against the small aromatic cage, thus considerably impairing the binding potency of the resulting xm6A. The native m6A mononucleotide binds to YTH with a moderate affinity, which can be modestly or considerably improved by different single-halogen substitutions. The single Br-substitution and double Cl-Br-substitution were determined as the best candidates to improve xm6A binding affinity, which are good compromises between the favorable halogen–π interactions and unfavorable steric effects eliciting from the substitutions.

The fluorescence of nitroaromatic fluorophores is highly sensitive to their environment and often exhibits a narrow “fluorescent window” in both solution and solid states. This limitation arises from the various fluorescence-quenching pathways, including S₁ → T_n intersystem crossing (ISC), formation of a twisted intramolecular charge transfer (TICT) state, and antiparallel molecular stacking. Here, we report a series of nitro-substituted triphenylamines (nitro-TPAs), in particular the pentiptycene-derived nitro-TPAs PX series, to investigate whether combined steric and electronic engineering can broaden the fluorescent window across a wide polarity range and in the solid state. While substituent electronic effects tune the push-pull character, the bulky pentiptycene scaffold shields the nitrogen center from solvation and suppresses intermolecular stacking in the solid phase. Notably, the isocyanide derivative PNC exhibits fluorescence in all six tested solvents, n-hexane, toluene, dichloromethane, N,N-dimethylformamide, and acetonitrile, as well as in both crystalline and powdered forms. This work demonstrates the effectiveness of integrating steric and electronic strategies to expand the fluorescence window of flexible nitroaromatic systems.

Recently, numerous heterohelicene derivatives have been synthesized; however, creating unsymmetrical heterohelicenes, particularly those with embedded nitrogen atoms, remains a challenge. In this study, we successfully synthesized unsymmetric azahelicenes through oxidative cyclodehydrogenation of N-bridged π-conjugated molecules. Due to the high regioselectivity at the 1-positions of amino-substituted anthracenes during oxidative couplings, we were able to obtain the corresponding azahelicenes by oxidizing N-bridged phenanthrene, anthracene and pyrenes. The UV/vis absorption spectra of these products exhibited a bathochromic shift as π-conjugation increased, while the fluorescence quantum yields correspondingly decreased. DFT calculations revealed that the configuration of the allowed HOMO–1 to LUMO transition in the lowest energy S₀–S₁ transition enhanced the quantum yield of anthracene-based azahelicenes. These findings offer valuable insights for designing emissive helicenes with unsymmetrical structures.