ChemCatChem最新文献

Nitric oxide (NO) is an essential signaling molecule with several biological functions and holds great promise in biomedical applications. However, NO delivery strategies have been challenged with its inherent short half-life and limited transport distance in human tissues. Strategies focused on the catalytic production of NO at the target site would afford an effective biomaterial. Herein, we introduce a carbon dot (CD) platform featuring multivalent amine groups that catalyze the denitrosylation from S-nitrosothiols. In the present study, we have developed a novel multivalent amine functionalized carbon dots to catalytically transform endogenous prodrugs S-nitrosothiols to generate NO at physiological conditions. The mechanism of NO generation follows a nucleophilic attack of the surface primary amine groups on the electrophilic thiol group of S-nitrosothiols, which is supported by various control studies and electron paramagnetic resonance (EPR). Notably, the release of NO is easily tuned by the prodrug concentration and surface density of amines on the CDs. Significantly, the NO-releasing feature of CDs is integrated with the prototissue module to evaluate the NO release profile in the biological environment. This study will deepen our understanding of designing useful multivalent systems to generate NO from endogenous prodrugs to realize their therapeutic potential.

The research of aggregation-induced emission (AIE) materials has aroused extensive interests during the past 20 years. Until recently, biomass-inspired AIE (BioAIE) materials have become highly attractive owing to the advantages of natural structural diversity, renewability, biocompatibility, and biodegradability of the biomass. In this concept, we focus on the sustainable production of BioAIE materials from biomass resources (biomacromolecules and small natural products) through extraction, chemical conversion, and physical conversion. Chemical conversion is especially stated, including catalytic conversion, schiff base reaction, “in water” reaction, and other chemical modifications. The luminescence mechanism of AIE behaviors along with their structure–property relationships is emphasized, and the applications are addressed as well. An outlook is provided to highlight the challenges and opportunities associated with the future development trend in this field.

The Front Cover highlights an immobilization method of four Keggin-type polyoxometalates (POMs) ([H₂W₁₂O₄₀]⁶⁻, [BW₁₂O₄₀]⁵⁻ [SiW₁₂O₄₀]⁴⁻, [PW₁₂O₄₀]³⁻) by using the reaction with an ionic liquid, 1-butyl-3-vinylimidazolium (BVIM) bromide. The reaction yields a hybrid material (BVIM-POM) as a water-insoluble salt. Cross polarization ¹H-³¹P NMR evidenced the presence of BVIM in the structure of (BVIM)₃[PW₁₂O₄₀]. The salt is mixed with carbon powder and Nafion to prepare an ink and casted on glassy carbon electrodes. The electrochemical behavior of immobilized POMs material is preserved while the electrochemical activity for nitrite reduction is measured. Differential electrochemical mass spectrometry (DEMS) shows the formation of NO and N₂O. More information can be found in the Research Article by Laurent Ruhlmann, Vasilica Badets, and co-workers (DOI: 10.1002/cctc.202400226).

The Cover Feature depicts a composite of processable conjugated polyelectrolytes and ionomers, forming a photocatalytic thin film with visible light activity. This film facilitates the creation of stable, versatile, and scalable photoreactors with enhanced charge separation and transfer for diverse photocatalytic applications. More information can be found in the Research Article by Jeehye Byun and co-workers (DOI: 10.1002/cctc.202400981).

A new type of alkyne esterification was developed under electrochemical conditions using alkyne aldehydes and alcohol compounds as starting materials and carbene and iodine as mediators. Through this method, external oxidants and transition metals are excluded and the alkyne bond is fully preserved. This approach is compatible with a wide range of substrates and various functional groups and provides a green and mild new route for directly converting alkyne aldehydes into alkyne esters.

Alumina-supported PtSn catalysts have been industrialized as the major catalysts for propane dehydrogenation, where Sn serves as an essential promoter. Herein, we synthesized a variety of Sn-doped alumina supports by regulating the precipitation order of Sn and Al precursors as follows: Sn precursor precipitated before Al, coprecipitated with Al, precipitated immediately after Al, or precipitates after 2 h of Al. The effect of Sn promoter on the surface acidic properties of alumina and, ultimately, on propane dehydrogenation was further investigated. The Sn species introduced by coprecipitation in alumina created additional surface strong acid sites, attributed to more Sn⁴⁺ species on the surface, which are able to remain stable during the subsequent treatment. Consequently, the coprecipitated Sn species in the corresponding catalyst donate more electrons to Pt and reduce the metal particle size. As a result, the catalyst with Pt supported on the coprecipitated support (Sn+Al) exhibits superior initial propane conversion (43.2%) and stability (k_d = 0.035 h⁻¹). This study provides new insight into the interaction between the two key components, tin promoter and alumina support, of Pt/Sn-Al₂O₃ catalysts.

Catalysis-based approaches offer versatile strategies for activating anticancer prodrugs, potentially allowing precise control over drug release and localization within tumor tissues while reducing systemic toxicity. In this study, we explore the role of the phenothiazine dye methylene blue (MB⁺) as a photocatalyst in conjunction with biologically relevant electron donors to facilitate the red-light conversion of two Pt(IV) complexes, denoted as cis,cis,trans-[PtCl₂(NH₃)₂(O₂CCH₂CH₂COOH)₂] (1) and trans-[Pt(O₂CCH₂CH₂COOH)₂1R,2R-(DACH)(ox)] (2), into cisplatin and oxaliplatin, respectively. Combining spectroscopic techniques (NMR, UV–vis, and flash photolysis) with computational methods, we reveal that the doubly reduced MB⁺ (leucomethylene blue, LMB) triggers the reductive elimination of axial ligands in the two Pt(IV) precursors, generating the corresponding Pt(II) anticancer drugs. In vitro experiments conducted on the human cervical cancer cell line CaSki, which harbors multiple copies of the integrated HPV-16 genome, and on nontumoral cells (HaCat) demonstrate that coadministration with Pt(IV) prodrugs improves MB⁺’s antiproliferative efficacy in cancer cells, particularly under red light exposure. This enhancement could be attributed to the catalytic production of Pt(II) species within the cellular environment.

Designing efficient and stable electrocatalysts for the hydrogen and oxygen evolution reactions (HER and OER) is crucial for green hydrogen production via the water-splitting system. The bifunctional electrocatalyst offers a promising strategy due to the simplified preparation process and reduced expenses. However, the single-component bifunctional catalysts often struggle to match the redox potential of water and to achieve proper adsorption/desorption of Gibbs free energy for both hydrogen and oxygen intermediates simultaneously. Herein, through precisely controlling the topological transformation path of the RuNiO_x precursor, we successfully prepared high-performance RuNi/Ni and Ru/NiO heterostructure electrocatalysts for the HER and OER, respectively. The energy level matching between the fabricated electrocatalyst and water oxidation/reduction potential confirms the feasibility of HER and OER. The synergistic effect between the active sites ensures rapid intermediate adsorption/desorption kinetics. As a result, the assembled alkaline overall water splitting setup achieves a current density of 1 A cm⁻² at 2 V and maintains stable operation at 100 mA cm⁻² for 100 hours.

Herein, an efficient and green procedure for the synthesis of lactic acid via the dehydrogenative coupling of ethylene glycol with methanol is reported. The reaction is carried out under mild conditions in the presence of a catalytic amount of ^CyPNP-Mn as the catalyst and ^tBuOK as the base and is an example of the deoxygenative coupling of a lower alcohol to form lactic acid via elegant metal–ligand cooperation with a homogeneous non-noble-metal catalyst in >99% conversion and selectivity. This transformation proceeds at low catalyst loading (0.00625 mol%) with a high turnover number (TON) of up to 6080 for lactic acid.

The photocatalytic conversion of biomass-derived compounds into value-added chemicals presents a promising protocol for the sustainable production of renewable chemicals. Our study explores the hydrogenation of biomass model compounds under visible light illumination. Zr was incorporated into the CeO₂ framework, forming a CeZrOx(1:0.5) solid solution, confirmed by powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS) analyses. The light uptake capacity of the CeZrOx solid solution was characterized using UV–visible spectroscopy. Additionally, the band structure of the CeZrOx solid solution was assessed using valance band X-ray photoelectron spectroscopy (VB-XPS) and Ultraviolet photoelectron spectroscopy (UPS) analysis, revealing a Z-Scheme, which was further confirmed by various control experiments. Upon decorating the CeZrOx(1:0.5) solid solution with 1 wt% palladium (Pd), the resulting 1Pd/CeZrOx(1:0.5) composite exhibited improved charge separation and enhanced visible light absorption capacity. This composite achieved ∼99% conversion of furfural to tetrahydrofurfuryl alcohol under a 15 W blue LED illumination and 0.2 MPa hydrogen. Similarly, it demonstrated ∼99% conversion of benzyl phenyl ether (BPE) to toluene and phenol under a 10 W blue LED illumination. Our findings elucidate the active sites and demonstrate the recyclability of mixed metal oxides for selective furfural hydrogenation and BPE hydrogenolysis under visible light.