 Ministry of Science, ICT and Future Planning* together with the Institute for Basic Science** (IBS), the main organization of the International Science and Business Belt project in South Korea, have announced that the Center for Self-assembly and Complexity*** have succeeded in developing new technology that introduces metal nanoparticles on the surface of polymer nanocapsules made of cucurbit[6]uril.

* Minister, Mun-Kee Choi ** Acting president, Hee-Sup Shin
*** Led by Kimoon Kim, both a director of the center and a professor at Pohang University of Science and
Technology (POSTECH)

。The metal-nanoparticle-decorated polymer nanocapsules exhibit the following properties in water: high stability for up to 6 months; high dispersibility; excellent catalytic activity; and reusability in carbon-carbon and carbon-nitrogen bond-forming reactions with 100% conversion efficiency. It also has many useful applications as various metal nanoparticles can be employed on the surface.

 The research outcomes were published online, May 19^th, in the prestigious chemistry journal, Angewandte Chemie (Impact Factor of 13.734).

* Title of paper: Highly Stable, Water-Dispersible Metal-Nanoparticle-decorated Polymer Nanocapsules and Their Catalytic Applications

* First author: Gyeongwon Yun, PhD student in the Department of Chemistry at Pohang University of Science and Technology (POSTECH)

* Corresponding author: Kimoon Kim, director of the Center for Self-assembly and Complexity at IBS

 The researchers have found that using polymer nanocapsules made of cucurbit[6]uril and metal salts can serve as a versatile platform where equal sized metal nanoparticles can be evenly distributed on the surface of the polymer nanocapsules.

。Cucurbit[6]uril has properties which strongly and selectively recognize organic and inorganic chemical species. This makes it possible to use it as a protecting agent which can stabilize metal nanoparticles by preventing them from clustering together.

。The size of metal nanoparticles can be adjusted by changing the rate of cucurbit[6]uril and metal salts. Various metal nanoparticles can also be employed.

。Moreover, the researchers have found that metal-nanoparticle-decorated polymer nanocapsules have high stability; catalytic activity; and reusability in carbon-carbon and carbon-nitrogen bond-forming reactions in water.

 These findings are meaningful in respect of the fact that these metal-nanoparticle-decorated polymer nanocapsules were developed with high stability and catalytic activity in environmentally benign solvents such as water. The investigation of the structure and the principles behind them are also of great significance.

。Metal nanoparticles have been researched and used in various areas due to their unique properties such as high surface to volume ratio, quantum confinement and surface plasmon effect.

。However, even though metal nanoparticles are variously used in industrial, pharmaceutical and agricultural (fertilizer) applications as a catalyst, toxic liquids such as toluene and hexane are usually used as solvents in the carbon-carbon and carbon-nitrogen bond-forming reactions. These toxic liquid solvents raise many issues for concern including environmental pollution, high cost of disposal, health problems and poisoning during the disposal process.

。However, this new technology is able to replace those toxic liquids as it allows carbon-carbon and carbon-nitrogen bond-formation with the use of metal nanoparticles as a catalyst, which has high stability in environmentally preferable solvents such as water. This suggests a possible application of eco-friendly solvents that can address environmental, safety and economic issues all at once. Since various kinds of metal nanoparticles can be employed on the surface of polymer nanocapsules, it is also potentially useful for other applications in the field of nano-medicine and bioimaging.

  “The research results demonstrated that this new technology shows high stability, dispersibility, catalytic activity, and reusability in water, which other existing metal nanoparticles on solid supports have not been able to do. It is important as it presents new possible applications in green solvents or bioimaging and nanomedicine fields,” says Kimoon Kim, director of the Center for Self-assembly and Complexity at IBS.