We believe that our manuscript on the preparation and coordination
chemistry of heterocyclic carbenes found interest in the scientific
community due to the importance heterocyclic carbenes have gained as
spectator ligands in organometallic chemistry and catalysis and as
organocatalysts themselves. The number of research groups worldwide working
with heterocyclic carbenes is still expanding and new and interesting
developments in this are reported regularly.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"This research has led to the
development of ruthenium-carbene-alkylidene
complexes, which are a highly efficient
catalyst for the
olefin-metathesis..."
We have aimed to summarize modern developments regarding the preparation of
heterocyclic carbenes and their metal complexes. For the beginner in this
field our account may serve as an introduction to the state of the art and
the description of the newest trends may keep the expert up to date.
Would you summarize the significance of your paper in
layman's terms?
The search for stable carbenes, i.e., of compounds possessing only two
bonds to a carbon atom, which at the same time bears a free electron pair,
has been going on for more than a century. The first derivative of this
type was reported by Professor Anthony J. Arduengo, III, of the University
of Alabama, in 1991, and this report has triggered a large research effort
regarding the preparation of new stable carbenes and their use as ligands
in metal complexes.
This research has led to the development of ruthenium-carbene-alkylidene
complexes, which are a highly efficient catalyst for the olefin-metathesis,
a discovery which, among others regarding olefin-metathesis, was honored
with the Nobel Prize in Chemistry in 2005, jointly to Yves Chauvin
(Institut Français du Pétrole, Rueil-Malmaison, France),
Robert H. Grubbs (California Institute of Technology, Pasadena, CA), and
Richard R. Schrock (Massachusetts Institute of Technology, Cambridge, MA)
"for the development of the metathesis method in organic synthesis."
How did you become involved in this research, and were
there any particular problems encountered along the way?
We have been working with isocyanide ligands and their metal complexes for
some years. Such complexes can be converted into complexes with
heterocyclic carbene ligands in a template-controlled reaction by a
nucleophilic attack at the coordinated isocyanide ligand. We have used this
reaction to generate complexes with heterocyclic carbene ligands, which
constitutes an alternative route to such derivatives when compared to the
direct coordination of a stable heterocyclic carbene to a metal center.
Where do you see your research leading in the
future?
The catalytic potential of complexes bearing heterocyclic carbene ligands
is enormous and new applications emerge practically monthly. Recently,
silver complexes with heterocyclic carbene ligands have been used as
antibiotics and palladium complexes bearing heterocyclic carbenes have been
shown to display potent anti-cancer activity.
Do you foresee any social or political implications for
your research?
Catalysis will be one of the tools to generate fuels and fine and bulk
chemicals in the future. The preparation of selective catalysts remains a
challenge and heterocyclic carbenes will have a significant impact on the
development of highly active and selective catalysts.
Prof. F. Ekkehardt Hahn
Anorganisch-Chemisches Institut der WWU Münster
Münster, Germany Web