Department of Chemistry and the Centre of Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
Langmuir. 2012 Jan 10;28(1):864-71. doi: 10.1021/la203662n. Epub 2011 Nov 30.
The chemical interfacial modification of organic solvent soluble 2.4 ± 0.5 nm maleimide-modified monolayer protected gold nanoparticles (2-C(12)AuNPs) with primary or secondary amines via Michael addition reactions is demonstrated. Michael addition reactions between 2-C(12)AuNPs and primary or secondary amines at ambient temperature and pressure and under the conditions where the AuNP is soluble and stable are possible albeit sluggish, often taking days to weeks to go to completion. The rates and efficacies of the these same reactions are drastically increased at hyperbaric pressure conditions (11 000 atm) with no observed adverse effect to the gold nanoparticle stability. The resulting Michael addition adducts (3-C(12)AuNPs) formed from 2-C(12)AuNPs and the corresponding amines were characterized by TEM and by comparison of the (1)H NMR spectra of the 3-C(12)AuNPs with those of model reactions of the same amines with N-dodecylmaleimide, 2. The Michael addition reactions occur more readily with 2 rather than 2-C(12)AuNPs, consistent with the local environment of the latter imposing additional steric or other barriers to the reaction. The use of hyperbaric conditions makes the reaction of the organic solvent soluble 2-C(12)AuNP via Michael addition a viable interfacial modification process that is otherwise impractical. The results also suggest that it is a useful protocol for facilitating Michael addition reactions generally in solution at low temperatures.
有机溶剂可溶性 2.4 ± 0.5nm 马来酰亚胺修饰的单分子层保护金纳米粒子（2-C(12)AuNPs）通过迈克尔加成反应与伯胺或仲胺进行化学界面修饰得到证明。在室温、常压下，AuNP 可溶且稳定的条件下，2-C(12)AuNP 与伯胺或仲胺之间的迈克尔加成反应虽然缓慢，但有可能发生，通常需要数天到数周才能完成。在超高压条件（11000atm）下，这些反应的速率和效率大大提高，而对金纳米粒子的稳定性没有观察到不利影响。由 2-C(12)AuNP 和相应胺形成的迈克尔加成加合物（3-C(12)AuNPs）通过 TEM 以及通过 3-C(12)AuNPs 的（1）H NMR 光谱与相同胺与 N-十二烷基马来酰亚胺的模型反应的比较进行了表征，2。迈克尔加成反应更容易与 2 而不是 2-C(12)AuNP 发生，这与后者的局部环境对反应施加额外的空间或其他障碍一致。超高压条件的使用使得通过迈克尔加成反应对有机溶剂可溶性 2-C(12)AuNP 进行反应成为一种可行的界面修饰过程，否则这种过程是不切实际的。结果还表明，这是一种在低温下在溶液中促进迈克尔加成反应的有用方案。
