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C. R. Chimie 19 (2016) 1371e1373
lable at ScienceDirectContents lists avaiComptes Rendus Chimie
www.sciencedirect.comEditorial/EditorialWarmest congratulations to Jean-Pierre Sauvage on the occasion
of the award of the Nobel Prize in Chemistry 2016The Nobel Prize in Chemistry 2016 was awarded jointly
to Jean-Pierre Sauvage, Sir J. Fraser Stoddart, and Bernard L.
Feringa “for the design and synthesis of molecular machines”.
Chemists worldwide are delighted and congratulate the
three laureates for their spectacular achievements and the
development of new concepts associatedwith fundamental
synthetic chemistry.
Jean-Pierre Sauvage (Fig. 1) did his PhD thesis under the
supervision of Professor Jean-Marie Lehn, on macrobicyclic
compounds (cryptands and cryptates) and their complex-
ing properties. He obtained his Doctorate degree from
Strasbourg University in 1971. He then spent a year as a
post-doctoral fellow at Oxford University, under Dr. M.L.H.
Green, after which he came back to Strasbourg, where he
joined Jean-Marie Lehn as a CNRS researcher. After 1976, he
became more and more involved in photochemistry. In
particular, with Jean-Marie Lehn, he developed new
photochemical systems related to photochemical splitting
of water to H2 and O2. In 1977, they proposed one of the
very first systems leading to the catalytic reduction of H2O
to H2 under the action of light and, in 1979, symmetrical
reactions (oxidation of H2O to O2 by visible light irradia-
tion) were made possible, using related reactions and
photochemical principles.
Jean-Pierre Sauvage created his own research laboratory
in 1980, within the University and in association with the
CNRS (“Laboratoire de chimie organo-minerale”). Through
his early work on catenanes and rotaxanes, he rapidly
established himself as a master of molecular topology.
Catenanes and rotaxanes are essential components of
molecular systems displaying novel properties in relation
to electron transfer, organic materials, polymers, etc.
Presently, the most popular field utilising catenanes and
rotaxanes is that of controlled dynamic systems, often
referred to as “molecular machines” or “molecular motors”.
When Sauvage and his group started to work in the field
of interlocking rings, the situation was very different from
what it is now. These compounds had beenmuch discussed
in the 1960s. Because of their intriguing topology, they
seemed to have triggered a lot of interest among molecularhttp://dx.doi.org/10.1016/j.crci.2016.11.002
1631-0748/© 2016 Published by Elsevier Masson SAS on behalf of Académie deschemists, even very long ago (from the beginning of the
20th century to the 1970s). Unfortunately, their synthesis
was exceedingly difficult. Elegant work, based on pure
organic chemistry, had been carried out in the 1960s and in
the 1970s by German chemists (Schill and coworkers). In
spite of the elegance of the synthetic route proposed by
German chemists, a practical synthesis of catenanes
seemed to be out of reach and the organic chemistry
community lost gradually interest in such compounds. At
the beginning of the 1980s, therewere virtually no research
teams working on catenanes and rotaxanes anymore and,
as expected, only very fewdif anydpublications dealing
with these compounds could be found in the literature.
In 1983, Sauvage and Dietrich-Buchecker proposed a
novel strategy for making interlocking rings (catenanes),
based on the three-dimensional template effect of a metal
centre (copper(I)). The templating core is able to gather two
(or several) organic ligands and to dispose them in a given
geometrical arrangement. Subsequent reactions allow one
to incorporate these fragments into desired chemical
structures and, in particular, to synthesize catenanes. This
first report clearly demonstrated that catenanes are
accessible species that can be obtained on a macroscopic
scale. It was a new birth for molecules which had fascinated
chemists for decades, but which were more discussion
objects or laboratory curiosities than real chemical species.
This early report was followed by other studies describing
the templated synthesis of new catenanes, either using
purely organic templates (Stoddart et al., 1989; Hunter,
Voegtle, 1992) or based on transition-metal-incorporating
assemblies (Fujita, 1994), to cite just a few. Many groups
then joined the field and, subsequently, proposed various
efficient synthetic routes also based on template effects.
Since 1983, the concept has been generalized and used
to create a whole family of topologically and chemically
fascinating molecules in Sauvage's group. Among the cat-
enanes, the record, reported in 1991, consisted of a gigantic
cycle (132-membered ring) and, separately interlocked to
it, six smaller rings. Some of the catenanes prepared in the
team could be crystallized and characterized by X-raysciences.
Fig. 1. Jean-Pierre Sauvage (photo: Catherine Schroder).
Editorial/Editorial / C. R. Chimie 19 (2016) 1371e13731372diffraction. In particular, the molecular arrangement of a 3-
ring system is particularly appealing from a chemical and
an aesthetic viewpoint. The compound and its derivatives
are also of interest in relation to energy and electron-
transfer processes. In addition, they constituted the pro-
totype of future macromolecular systems consisting of
interlocking rings arranged in a chain.
By applying a strategy derived from that described in
the first report on catenanes, the first molecular knot,
namely the trefoil knot, was synthesized in 1989 by Sauvage
and Dietrich-Buchecker. The compound is a topologically
fascinating object (the simplest non-trivial knot), and it is
clear that its preparation represents an interesting link
between topology, art, and biology. In fact, many of the
interlocking ring systems and knots made in the group
display topological properties identical to those of the
molecular objects formed by DNA in the course of recom-
bination or replication processes, and recognized by mo-
lecular biologists since the beginning of the seventies. This
first chemical knot can also be considered as a real syn-
thetic achievement, since chemists had discussed knots as
hypothetical chemical objects for several decades before
they were actually made.
In recent synthesis, performed in collaboration with
Grubbs (Nobel laureate 2005) and coworkers (Caltech,
USA), the original preparation of the [2]catenane (consist-
ing of two interlocking rings), published in the 1980s, was
improved in a spectacular fashion by using a methodology
based on the ring-closing metathesis of olefins. In a few
steps from commercially available compounds, a [2]cate-
nane was obtained with an overall yield of about 70%, the
cyclisation reaction, which is certainly the key reaction,
being almost quantitative. Furthermore, the use of a second
metal centre (Pd(II)) to make the rings allowed the cate-
nane to be formed under thermodynamic control, allowingthe system to reach the most stable situation, which is
indeed the catenane. This work, carried out in association
with M. Fujita and his group (Tokyo), demonstrated that
catenanes can be obtained quantitatively and very simply,
from organic fragments, using the concepts of coordination
chemistry.
Another spectacular synthesis improvement was the
trefoil knot, which could be made in only small amounts
(50 mg) 15 years ago, but which could be obtained at the
gram scale thanks to new preparative methodologies.
A fascinating aspect of knots is their chirality. A trefoil
knot could be resolved into its enantiomers (right- and left-
handed knots) and their absolute configuration could even
be determined by X-ray crystallography. The chiroptical
properties of these resolved knots show in particular huge
optical rotation.
The original copper(I)-templated synthesis of catenanes
was generalised and afforded a broad family of porphyrin-
containing catenanes and rotaxanes. In association with
photophysicists (Harriman et al., Austin, USA, and Flamigni
and colleagues, Bologna, Italy), it was shown that ultrafast
electron transfer takes place between a photoexcited
electron donor and an acceptor, in a way which is remi-
niscent of the natural photosynthetic reaction centre, or
that long-range energy transfer processes are operative in
transition-metal-assembled multiporphyrins.
Controlling and triggering motion at the molecular level
became a rapidly expanding field of research. In molecular
biology, several extremely important systems contain
motor-like assemblies. Given parts of the ensemble are set
in motion under the action of an external signal (most of
the time, of chemical nature), while other fragments are
regarded as motionless. ATP-synthase is probably the most
spectacular example, acting as a rotary motor. Bi- or multi-
stable highly functional [2]catenanes, which can be set in
motion in a precisely defined fashion, have been elaborated
in Sauvage's group as early as in 1994. One ring glides
within the other ring under the action of an electro-
chemical signal, the process being reversible. Further im-
provements afforded new “pirouetting” machines, able to
move within milliseconds or even less, after an electro-
chemical signal has been sent to the molecule.
Another contribution from the group of Sauvage is a
rotaxane dimer whose behaviour is reminiscent of natural
muscles. In this particular case, two filaments can glide
along one another in a controlled fashion. The overall effect
is that the synthetic rotaxane dimer can be stretched or
contracted at will, using a chemical signal. The linearly ar-
ranged two-component assembly is about 85 Å long in its
stretched geometry. After the chemical stimulus has been
sent to the molecular system, contraction occurs so as to
afford a species whose overall length is only 65 Å.
Electrochemically driven machines, based on the cop-
per(I)/copper(II) couple, have also been assembled on
electrode surfaces, with the hope that real electronic and
memory storage devices will be fabricated.
Sauvage's group also developed a new family of dy-
namic systems, incorporating octahedral ruthenium(II)
complexes of the rotaxane or catenane family. These new
compounds behave as light-driven molecular machines,
photonic or thermal energy being the only source of energy
Editorial/Editorial / C. R. Chimie 19 (2016) 1371e1373 1373responsible for the motion. They represent an important
class of controlled dynamic systems besides the now well-
established electrochemically driven systems. Two-
dimensional interlocking networks were also assembled,
which could lead to highly flexible and dynamic mem-
branes, whose pore size could be controlled by an external
stimulus.
These chemically or electrochemically driven machine-
like molecules, as well as recently proposed photoactive
species based on ruthenium(II) complexes, can be thought
of as the molecular components of future nano- or micro-
scopic chemo-, photo-, or electromechanical devices. Mo-
lecular machines andmotors could find applications in, e.g.,the elaboration of microrobots or nanometric systems
acting as information storage and processing devices.
The pioneering role of Jean-Pierre Sauvage in chemical
synthesis towards controlled molecular topology has been
recognized by a number of national and international
awards. He was elected a member of the French “Academie
des sciences” in 1997 and belongs to the Editorial Board of
Comptes rendus Chimie.
Pierre Braunstein, Editor-in-Chief
Strasbourg, France


Warmest congratulations to Jean-Pierre Sauvage on the occasion of the award of the Nobel Prize in Chemistry 2016

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Comparaison de différentes méthodes d'extraction d'acides dicaféoylquiniques à partir d'une plante halophile

A tribute to Edmond Payen: A singular vision between academia and industry

An epoxide ring-opening reaction by using sol–gel-synthesized palladium supported on a strontium hydroxyl fluoride catalyst

Recent progress in catalytic NO decomposition

Co-K and Mo-K edges Quick-XAS study of the sulphidation properties of Mo/Al<sub>2</sub>O<sub>3</sub> and CoMo/Al<sub>2</sub>O<sub>3</sub> catalysts

Warmest congratulations to Jean-Pierre Sauvage on the occasion of the award of the Nobel Prize in Chemistry 2016

Mineral studies in enamel, an exemplary model system at the interface between physics, chemistry and medical sciences

Targeting protein–protein interactions, a wide open field for drug design

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Manganese(III) porphyrin supported onto multi-walled carbon nanotubes for heterogeneous oxidation of synthetic textile dyes and 2,6-dimethylphenol by <i>tert</i>-butyl hydroperoxide

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