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The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h(-1) , which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2 . Furthermore, the catalyst is tolerant toward a variety of amines, which includes aromatic, aliphatic, secondary, and primary amines. Preliminary mechanistic studies suggest that the N-alkyl formamide might be an intermediate in the N-methylation of amine process. Moreover, through a one-pot process, it is possible to convert primary amines, aldehydes, and CO2 into unsymmetrical tertiary amines with H2 as a reductant in the presence of the Au catalyst.

Specific detection or imaging protein has high potential to contribute greatly to medical diagnosis, biological research, and therapeutic applications. The level of human serum albumin (HSA) in blood is related to a variety of diseases and thus serves as an important biomarker for fast clinical diagnosis. Here we report the use of aggregation-induced emission (AIE) based supramolecular assembly to design biomolecular responsive smart organic nanomaterials for detection protein HSA. The designed nanoprobes were aggregates of small molecules and silent in fluorescence, but in the presence of HSA they disassembled and produced a clear turn-on fluorescent signal. Of a small library of nanoprobes constructed for HSA detection, structure-optical signaling and screening studies revealed that nanoprobe 7 is the most efficient one. Mechanism studies showed that nanoprobe 7 was bonded with Site I of HSA through the multiple noncovalent interactions. The resultant restriction of intramolecular rotation of nanoprobe 7 in the hydrophobic cavity of HSA induced fluorescent emission, which was validated by competitive binding assays and molecular docking. More importantly, nanoprobe 7 was successfully applied to recognize and quantify HSA in human serum samples. This study demonstrates nanoprobe 7 is a promising tool for clinical real and fast detection of HSA and thus may find many applications, and the molecular assembly based on AIE also opens a new avenue for designing smart nanomaterials for the sensitive and selective detection for varied analytes.

Semiconductor photocatalysis may be a promising strategy to face energy and environmental issues because it utilizes the solar energy as energy source. The artificially Z‐scheme photocatalytic system has attracted special interests owing to its high efficiency and strong redox ability. Graphitic carbon nitride nanosheets (g‐C3N4 NSs) display prominent performances, which are intensively investigated. Herein, we constructed an all‐solid‐state Z‐scheme photocatalytic system and firstly immobilized g‐C3N4 nanosheets on TiO2 nanotube arrays (TNTAs) by a simple method. The microstructures of prepared g‐C3N4 NSs/TNTAs photocatalyst were characterized by XRD, X‐ray photoelectron spectroscopy, SEM and TEM. The features of light absorption, charge separation, and charge transfer were analyzed by UV/Vis diffuse reflectance techniques, photoluminescence spectroscopy, electrochemical atomic force microscopy, and photocurrent measurement. The synthesized g‐C3N4 NSs/TNTAs samples shows enhanced photocatalytic efficiency for rhodamine B degradation under visible light, which is four times more than that of pure TNTAs. Tetracycline hydrochloride could also be effectively degraded under visible light, which contributes to reducing antibiotic residues in wastewater. Additionally, g‐C3N4 NSs/TNTAs also possess other advantages such as well long‐term stability and easily recyclable properties. A reaction mechanism is also proposed.

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