Precision Chemistry最新文献

A silver-catalyzed intermolecular (3 + 2) annulation of siloxy alkynes and 3-aminooxetanes has been developed. This process provides mild and convenient access to useful γ-butyrolactams with high regio- and stereoselectivity. Mechanistically, intermolecular C–N bond formation likely precedes oxetane ring opening.

The synergistic integration of metal catalysis with electrochemistry has emerged as a powerful tool for organic synthesis. However, in nickel-catalyzed electrochemical cross-coupling reactions, mismatches between external conditions and reaction rates often lead to side reactions such as catalyst deactivation, homocoupling, and protonation. Addressing this issue through the development of strategies is highly desirable. Herein, we report the successful merging of photochemistry with electrochemistry to facilitate nickel-catalyzed C–O cross-coupling reactions, providing a practical method for the synthesis of alkyl aryl ethers. Preliminary mechanistic studies suggest that this photoelectrochemical strategy effectively enhances the efficiency of nickel-catalyzed C–O cross-coupling reactions compared to traditional electrochemical methods by regenerating the active Ni^I catalyst from the Ni^II species through photochemistry.

Organic singlet diradicaloids are promising photothermal agents owing to their exceptional light-harvesting capabilities and efficient light-to-heat conversion. In this study, two stable dibenzononazethrene isomers, DBNZ1 and DBNZ2, are synthesized through a concise method and isolated in crystalline form. An open-shell singlet diradical ground state, with diradical indices of 0.67 and 0.69, is confirmed through a combination of theoretical and experimental approaches. Steady-state and time-resolved absorption spectroscopy demonstrated efficient light absorption in the far-red region and excellent light-to-heat conversion, attributed to a rapid nonradiative process. Encapsulation of DBNZ1 with an amphiphilic polymer produced water-dispersible nanoparticles (DBNZ1-NPs) with enhanced stability, achieving an impressive photothermal conversion efficiency of 72.9%. An in vitro photothermal therapy study demonstrated that DBNZ1-NPs functioned as biocompatible tumor ablation agents when activated by an 808 nm laser, highlighting their potential application in cancer photothermal therapy.

Gold nanospheres with uniform sizes greater than 30 nm are essential to quantitative lateral flow immunoassays for the rapid detection of pathogens such as viruses, bacteria, and fungi. However, scaling up their synthesis for commercial applications remains challenging due to the necessity to introduce the precursor dropwise. Herein, we report the synthesis of Au cubes with an edge length of 30 nm using one-shot injection of the precursor, followed by aging to transform the cubes into uniform spheres of 35 nm in diameter. Our mechanistic study based on qualitative and quantitative analyses using surface-enhanced Raman scattering and inductively coupled plasma mass spectrometry, respectively, suggests that Br^- desorption from the surface of Au nanocubes at an elevated temperature was responsible for the shape transformation by inducing oxidative etching and atomic migration in the outermost layer. By eliminating the need for dropwise addition, this protocol is well-suited for the mass production of Au nanospheres in a continuous flow reactor for future incorporation into quantitative point-of-care sensors.

Extracellular vesicles (EV) have emerged as key factors for intercellular communication, disease biomarkers, and vaccines, but EV populations generally exhibit broad heterogeneity, making single-vesicle measurements critical in order to understand the roles played by EVs and the pathways they utilize. To circumvent the exhaustive isolation and concentration protocols and/or long incubation periods required by common single-vesicle characterization methods, we have developed a method for the in situ study of single EVs from crude Pseudomonas aeruginosa culture in real-time with minimal sample preparation using nanopore-based zero-mode waveguides (ZMW). The dimensions of the ZMW allow only a single EV to occupy the nanopore volume, making it possible to monitor large arrays of single EVs one-at-a-time in parallel. Furthermore, the attoliter-volume ZMW nanopores restrict the much larger P. aeruginosa cells from entering the observation volume, eliminating the need to isolate EVs from their parent cells. Lipophilic fluorophores are used to selectively tag the EV membrane, thereby restricting optical observations to single EVs captured one-at-a-time in individual ZMW nanopores. By fashioning the ZMWs into 21 × 21 arrays, 441 individual observation volumes can be observed in parallel, revealing the heterogeneity of single EV responses, which is usually masked by ensemble averaging when examining hundreds of events at once without spatial segregation. The minimal sample preparation and ability to monitor the sample in situ enables real-time analysis of changes in the bacterial culture environment, since detection of EVs is governed solely by diffusion of the particle into the ZMW optical volume. The work described here presents an approach for studying EV heterogeneity in crude bacterial culture and makes it possible to observe shifts in the vesicle population in response to culture perturbations in real-time.

Canted antiferromagnets have attracted considerable research interest due to their distinctive physical characteristics. However, suitable material platforms for such investigations remain limited. In this study, we present the exceptional magnetic and magneto-transport properties of Fe₃SnSb polycrystals synthesized via a two-step solid-state reaction process. A comprehensive investigation into the magnetic properties and specific heat of Fe₃SnSb polycrystals has determined that the compound possesses a Néel temperature of 156 K. Furthermore, we have identified the coexistence of ferromagnetism and antiferromagnetism in Fe₃SnSb below 50 K, alongside the relatively rare phenomenon of canted antiferromagnetism, which is proved by a nonsaturating nonlinear increase in magnetization with increasing magnetic field. Electrical transport measurements on Fe₃SnSb reveal metallic behavior, and the material demonstrates a pronounced negative magnetoresistance across the entire temperature range examined, peaking at 14.1%, surpassing the values observed in most known antiferromagnetic materials. The discovery of Fe₃SnSb as a canted antiferromagnetic material expands the family of such materials and paves the way for extensive future research into interesting physical phenomena and the potential development of innovative device applications.