Catalytic transfer hydrogenation of biomass-derived furfural to furfuryl alcohol with formic acid as hydrogen donor over CuCs-MCM catalyst

Catalytic transfer hydroge nation(CTH) of furfural(FF) to furfu ryl alcohol(FFA) has received great intere st in recent years.He rein,Cu-Cs bimetallic supported catalyst,CuCs(2)-MCM,was developed for the CTH of FF to FFA using formic as hydrogen donor.CuCs(2)-MCM achieved a 99.6% FFA yield at an optimized reaction conditions of 170℃,1 h.Cu species in CuCs(2)-MCM had dual functions in catalytically decomposing formic acid to generate hydrogen and hydrogenating FF to FFA.The doping of Cs made the size of Cu particles smaller and improved the dispersion of the Cu active sites.Impo rtantly,the Cs species played a favorable role in enhancing the hydrogenation activity as a promoter by adjusting the surface acidity of Cu species to an appropriate level.Correlation analysis showed that surface acidity is the primary factor to affect the catalytic activity of CuCs(2)-MCM.     

Site-Specific Detection of Free Radicals in Membranes Using an Amphiphilic Spin Trap

The detection of free radicals and related species has attracted considerable attention in recent years due to their critical roles in physiological and pathological processes. Among the various methods for the detection of free radicals, electron spin resonance coupled with spin-trapping technique has been an effective approach for the characterization and quantification of free radicals due to its high specificity. In this study, we designed and synthesized a novel amphiphilic spin trap, 2-(diethoxyphosphoryl)-2-heptadecanyl-3,4-dihydro-2H-pyrrole-1-oxide (DEPHdPO), from 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide with a long hydrocarbon chain at the C-5 position of the pyrroline ring, providing the amphiphilic character. The free-radical-trapping ability of DEPHdPO was evaluated by capturing hydroxyl radicals (^·OH), superoxide anions (\( {\text{O}}_{2}^{ \cdot - } \)), and carbon-centered free radicals in a model membrane prepared from sodium dodecyl sulfate (SDS). The results indicate that the hydrophobic hydrocarbon chain of DEPHdPO can be inserted into the inner core of SDS micelles, and the hydrophilic nitronyl functional moiety is located on the surface layer. Thus, various free radicals, including ^·OH radicals, \( {\text{O}}_{2}^{ \cdot - } \) anions, and carbon-centered radicals could be site-specifically detected near the membrane surface. Moreover, DEPHdPO could be successfully located on the surface of thylakoid membranes, and the nearby photo-initiated \( {\text{O}}_{2}^{ \cdot - } \) anions could be trapped site-specifically.     

Water‐Soluble Monolayer Molybdenum Disulfide Quantum Dots with Upconversion Fluorescence

Uniform water‐soluble monolayer MoS₂ quantum dots (MQDs) with lateral sizes of ≈2.1 nm, a clearly zigzag‐terminated edge, and a hexagonal lattice structure are achieved using ammonium molybdate, thiourea, and N‐acetyl‐l ‐cysteine (NAC) as precursors and the capping reagent in a facile one‐pot hydrothermal approach. MQDs have good dispersity and high stability in aqueous suspension and exhibit a significantly larger direct bandgap (3.96 eV) compared to monolayer MoS₂ nanosheets (1.89 eV). Pronounced blue‐shifts in the wavelengths of both the excitonic absorption and intrinsic state emission with activated strong luminescence at room temperature beyond monolayer MoS₂ nanosheets is demonstrated. Unusual upconversion photoluminescence is also observed and is caused by two successive transfers of energy from the near‐infrared (NIR) absorption generated by the NAC capping reagent to the hexagonal structure of MQDs. Additional optical properties of MQDs may provide numerous exciting technological applications. Here, MQDs are demonstrated as a highly selective fluorescent reagent for detecting tetracycline hydrochloride under UV and NIR irradiation.