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 19th,
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.
|