Understanding the oxidative stability of gold monolayer-protected clusters in the presence of halide ions under ambient conditions
Understanding the oxidative stability of gold monolayer-protected clusters in the presence of halide ions under ambient conditions
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DOI：
10.1021/la0627415
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发表时间：
2007-03-13
期刊：
影响因子：
3.9
通讯作者：
Scott, Robert W. J.
中科院分区：
文献类型：
--
作者：
Dasog, Mita;Scott, Robert W. J.
我们报告了通过改进的 Brust-Schiffrin 方法制备的硫醇钝化金单层保护簇 (MPC) 的氧化稳定性。在卤化物阴离子存在的情况下，当 Au MPC 暴露在空气中时，可以观察到锚定的硫醇基团依次氧化为二硫化物和磺酸盐基团，以及 Au 原子氧化为 Au3+ 物质。此外，平均纳米颗粒尺寸通过MPC的聚集而增长，最终导致Au MPC的部分氧化和剩余纳米颗粒从溶液中沉淀，或在高卤化物浓度下完全氧化金原子。这些结果表明，在卤化物阴离子存在的情况下，Au MPC 在空气中容易氧化，因此，必须彻底去除使用四辛基溴化铵等相转移试剂制成的颗粒，以避免 Au MPC 的粒径增长、氧化和沉淀。此外，对于涉及 Au MPC 的生物应用，必须注意确保在含有卤化物阴离子的介质中工作时，空气中的 MPC 氧化不会出现问题。
We report on the oxidative stability of thiol-passivated Au monolayer-protected clusters (MPCs) made via a modified Brust-Schiffrin method. A sequential oxidation of the anchored thiol groups to disulfide and sulfonate groups and the oxidation of Au atoms to Au3+ species is observed upon exposure of Au MPCs to air in the presence of halide anions. In addition, the average nanoparticle size grows via aggregation of the MPCs, leading eventually to partial oxidation of the Au MPCs and precipitation of the remaining nanoparticles from solution or to complete oxidation of the gold atoms at high halide concentrations. These results show that Au MPCs are prone to oxidation in air in the presence of halide anions, and therefore, particles made using phase transfer reagents such as tetraoctylammonium bromide must be thoroughly removed to avoid particle size growth, oxidation, and precipitation of the Au MPCs. In addition, for biological applications involving Au MPCs, care must be taken to ensure that oxidation of MPCs in air is not problematic when working in media containing halide anions.