The Brust-Schiffrin (BS) method for gold nanoparticle (Au NP) synthesis is celebrated for its ability to produce highly monodisperse NPs from toluene-water solutions, in contrast to aqueous methods, such as the Turkevich method. Despite the method’s success, the actual formation mechanisms remain largely unknown due to difficulty in studying the intermediates with species-differentiating techniques such as mass spectrometry (MS) or nuclear magnetic resonance (NMR). The issue lies in the use of solvents poorly compatible with these techniques and the difficulty in differentiating useful intermediate species from side products and impurities in such one-pot reactions. Herein, we use our recently formulated fully aqueous BS reaction to study the formation mechanisms. MS is chiefly employed to capture the intermediate species, and the Au₂₅(SR)₁₈ nanocluster is used as a thermodynamically reliable end-point. We find that the BS method may comprise a unilateral complex-shedding stage in addition to the known thiol-etching stage.

中文翻译：

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通过质谱揭示 Au25(SR)18 的 Brust-Schiffrin 形成机制

与 Turkevich 等水性方法相比，用于金纳米颗粒 (Au NP) 合成的 Brust-Schiffrin (BS) 方法因其能够从甲苯水溶液中生产高度单分散的 NP 而闻名。尽管该方法取得了成功，但由于难以使用质谱（MS）或核磁共振（NMR）等物种区分技术来研究中间体，因此实际的形成机制仍然很大程度上未知。问题在于使用与这些技术相容性差的溶剂，以及在此类一锅反应中难以区分有用的中间体物质与副产物和杂质。在这里，我们使用我们最近制定的全水 BS 反应来研究形成机制。 MS 主要用于捕获中间物质，Au ₂₅ (SR) ₁₈纳米团簇用作热力学可靠的终点。我们发现，除了已知的硫醇蚀刻阶段外，BS 方法还可能包括单侧复杂脱落阶段。