KAUST Catalysis Center (KCC), Physical Sciences and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
University of Tabuk, Chemistry Department, College of AlWajh, Al Wajh, Saudi Arabia.
Nat Chem. 2017 Sep;9(9):890-895. doi: 10.1038/nchem.2752. Epub 2017 Mar 27.
Elucidating the binding mode of carboxylate-containing ligands to gold nanoparticles (AuNPs) is crucial to understand their stabilizing role. A detailed picture of the three-dimensional structure and coordination modes of citrate, acetate, succinate and glutarate to AuNPs is obtained by C and Na solid-state NMR in combination with computational modelling and electron microscopy. The binding between the carboxylates and the AuNP surface is found to occur in three different modes. These three modes are simultaneously present at low citrate to gold ratios, while a monocarboxylate monodentate (1κO) mode is favoured at high citrate:gold ratios. The surface AuNP atoms are found to be predominantly in the zero oxidation state after citrate coordination, although trace amounts of Au are observed. Na NMR experiments show that Na ions are present near the gold surface, indicating that carboxylate binding occurs as a 2e L-type interaction for each oxygen atom involved. This approach has broad potential to probe the binding of a variety of ligands to metal nanoparticles.
阐明含羧酸盐配体与金纳米粒子（AuNPs）的结合模式对于理解其稳定作用至关重要。通过 C 和 Na 固态 NMR 结合计算建模和电子显微镜，获得了柠檬酸、醋酸盐、琥珀酸和戊二酸与 AuNPs 的三维结构和配位模式的详细图片。发现羧酸盐与 AuNP 表面的结合以三种不同的模式发生。这三种模式同时存在于低柠檬酸与金的比例下，而在高柠檬酸与金的比例下，则有利于单羧酸盐单齿（1κO）模式。尽管观察到痕量的 Au，但发现在柠檬酸配位后，表面 AuNP 原子主要处于零氧化态。Na NMR 实验表明，Na 离子存在于金表面附近，表明羧酸盐的结合发生作为涉及的每个氧原子的 2e L 型相互作用。这种方法具有广泛的潜力，可以探测各种配体与金属纳米粒子的结合。
