Room-temperature synthesis of 4-alkyl/aryl-2-aminothiazoles from vinyl azides and ammonium thiocyanate was accomplished with the aid of copper salts and blue LED irradiation. Mechanism investigation indicates that in situ-formed Cu­(NCS)2 – plays dual important roles in the reaction: (1) as the photocatalyst to activate vinyl azides, (2) as the Lewis acid catalyst to promote ring opening of 2H-azirines with thiocyanide. This process is distinguished by high yields, mild conditions, low catalyst loadings, and tolerating numerous alkyl- and aryl vinyl azides with an array of functional groups.

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Eosin Y, a common organo-photocatalyst in visible-light photoredox processes, was found to show excellent catalytic activities for thermal redox reactions under a catalytic amount of Cu­(OAc)2. With this catalytic system, vinyl azides and ketene silyl acetals combine to form formal [3 + 2] cycloadducts by α-ester radical addition without light irradiation. This method provides a mild and straightforward paradigm to prepare important synthons of five-membered ene-γ-lactams and bridge ring lactams. It is the first example of an eosin Y-catalyzed redox reaction in the dark.

Foods contaminated by foodborne pathogens have always been a great threat to human life. Herein, we constructed an electrochemical immunosensor for Salmonella detection by using a Fe 3 O 4 @ graphene modified electrode. Because of the excellent electrical conductivity and mechanical stability of graphene and the large specific surface area of Fe 3 O 4 , the Fe 3 O 4 @ graphene nanocomposite exhibits an excellent electrical signal, which greatly increased the sensitivity of the immunosensor. Gold nanoparticles were deposited on Fe 3 O 4 @ graphene nanocomposite by electrochemical technology for the immobilization of the antibody. Cyclic voltammetry was selected to electrochemically characterize the construction process of immunosensors. The microstructure and morphology of related nanocomposites were analyzed by scanning electron microscopy. Under optimized experimental conditions, a good linear relationship was achieved in the Salmonella concentration range of 2.4 × 10 2 to 2.4 × 10 7 cfu/mL, and the limit of detection of the immunosensor was 2.4 × 10 2 cfu/mL. Additionally, the constructed immunosensor exhibited acceptable selectivity, reproducibility, and stability and provides a new reference for detecting pathogenic bacteria in milk.