Young Adam J, Sauer Markus, Rubio Guilherme M D M, Sato Akiko, Foelske Annette, Serpell Christopher J, Chin Jia Min, Reithofer Michael R
Gray Centre for Advanced Materials, School of Mathematics and Physical Sciences, University of Hull, Cottingham Road, Hull, East Riding of Yorkshire, HU6 7RX, UK.
Nanoscale. 2019 Apr 25;11(17):8327-8333. doi: 10.1039/c9nr00905a.
Although N-heterocyclic carbenes (NHCs) have been demonstrated as suitable ligands for the stabilisation of gold nanoparticles (AuNPs) through a variety of methods, the manner in which such AuNPs form is yet to be fully elucidated. We report a simple and fast one-step synthesis of uniform chiral (l/d)-histidin-2-ylidene stabilised gold nanoparticles using the organometallic Au(i) complex as a well defined starting material. The resulting nanoparticles have an average size of 2.35 ± 0.43 nm for the L analog whereas an average size of 2.25 ± 0.39 nm was found for the D analog. X-ray photoelectron spectroscopy analyses reveal the presence of Au(i) and Au(0) in all NHC stabilised AuNPs. In contrast, measured X-ray photoelectron spectra of dodecanethiol protected gold nanoparticles showed only the presence of a Au(0) species. This observation leads us to postulate that AuNPs synthesised from organometallic NHC-Au(i) complexes exhibit a monolayer of Au(i) surrounding a Au(0) core. This work highlights the importance of synthetic method choice for NHC-stabilized AuNPs, as this could determine Au oxidation states and resulting AuNP properties such as catalytic activities and stabilities.
尽管通过多种方法已证明N-杂环卡宾（NHCs）是稳定金纳米颗粒（AuNPs）的合适配体，但此类AuNPs的形成方式尚未完全阐明。我们报道了一种简单快速的一步法合成，使用有机金属Au（i）配合物作为明确的起始原料，合成出均匀的手性（l/d）-组氨酸-2-亚基稳定的金纳米颗粒。所得纳米颗粒中，L型类似物的平均尺寸为2.35±0.43nm，而D型类似物的平均尺寸为2.25±0.39nm。X射线光电子能谱分析表明，在所有NHC稳定的AuNPs中均存在Au（i）和Au（0）。相比之下，十二烷硫醇保护的金纳米颗粒的X射线光电子能谱测量结果仅显示存在Au（0）物种。这一观察结果使我们推测，由有机金属NHC-Au（i）配合物合成的AuNPs在Au（0）核周围呈现出单层Au（i）。这项工作突出了合成方法选择对NHC稳定的AuNPs的重要性，因为这可能决定Au的氧化态以及由此产生的AuNP性质，如催化活性和稳定性。
