The efficient functionalization and coupling of macromolecular building
blocks has remained a major challenge for several decades. The introduction
of "click chemistry" methods—a chemical philosophy introduced by
K. Barry Sharpless of The Scripps Research Institute
in 2001, which describes chemistry tailored to generate substances
quickly and reliably by joining small units together—seems to have
solved this challenge by allowing efficient functionalization under mild
conditions with readily available reagents.
"...the use of click chemistry in
macromolecular science has flourished over
the past several years."
Therefore, the combination of click chemistry and macromolecules was widely
accepted within the polymer society within only a few years. This critical
review article summarizes recent efforts of click chemistry to
functionalize macromolecules and to engineer new macromolecular articles.
As such, the article serves as a source of inspiration as well as a
database for people working in the field.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
The article summarizes and critically discusses the use of click chemistry
in macromolecular science, which has found widespread adaptation within
just a few years.
Would you summarize the significance of your paper
in layman's terms?
Doing chemistry with large macromolecular building blocks provides a major
challenge in purification if the transformation does not go to completion.
In fact, separating two macromolecules with, e.g., different end-groups, is
very difficult. Therefore, a very efficient reaction procedure is required
to circumvent the purification problem.
Click chemistry in general and the copper(I) catalyzed azide-alkyne
cycloaddition in particular represents a highly efficient coupling
procedure that was introduced by Sharpless, the 2001 Nobel Prize Laureate
in Chemistry, with a stringent sets of requirements including high yields,
mild conditions, readily available starting materials, and easy
purification. These requirements perfectly fit the longstanding challenge
of performing efficient chemical transformations on macromolecules.
Therefore, the use of click chemistry in macromolecular science has
flourished over the past several years. Click chemistry not only allowed
efficient functionalization of macromolecular structures, but also enabled
coupling of polymeric building blocks, leading to new macromolecular
architectures that were not easily accessible without click chemistry, such
as cyclic polymer structures.
How did you become involved in this research, and
were there any problems along the way?
In 2006, we were interested in the preparation of star-shaped
poly(caprolactone) in an efficient way. After several attempts, we found
that the use of click chemistry, in combination with microwave irradiation,
yielded the star-shaped polymer in a high yield in only 15 minutes (Benz A,
Hartig JS, "Redesigned tetrads with altered hydrogen bonding patterns
enable programming of quadruplex topologies," Chem Commun
34:4010-12, Sep 14, 2008). At that time, this was the first report of using
click chemistry to make star-shaped polymers, and after that many more
reports appeared in the literature.
Where do you see your research leading in the
In current research, many studies demonstrate that click chemistry can be
used to prepare functionalized macromolecules and new macromolecular
architectures. However, many of these reports focus on the synthetic aspect
only. The focus of research combining macromolecules and click chemistry
will change from demonstrating the advantages and feasibility towards using
click chemistry to prepare and apply novel functional macromolecular
architectures that were previously not accessible.
Prof. Dr. Ulrich S. Schubert
Chair for Organic and Macromolecular Chemistry
Jena, Germany Web
Keywords: macromolecular building blocks, click chemistry, k.
barry sharpless, macromolecules, performing efficient chemical
transformations on macromolecules, functionalized macromolecules,
star-shaped poly(caprolactone), star-shaped polymer, microwave