CHANDLER MEDAL AWARD LECTURE
"Perspectives in Chemistry: From Supramolecular Chemistry towards Adaptive Chemistry"
Presented by Jean-Marie Lehn, College de France
Supramolecular chemistry is actively exploring systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, on the basis of the molecular information stored in the covalent framework of the components and read out at the supramolecular level through specific non-covalent interactional algorithms, thus behaving as programmed chemical systems.
The design of molecular information controlled, “programmed” and functional self-organizing systems provides an original approach to nanoscience and nanotechnology. The spontaneous but controlled generation of well-defined, functional molecular and supramolecular architectures of nanometric size through self-organization represents a means of performing programmed engineering and processing of functional nanostructures. It offers a very powerful alternative to nanofabrication and to nanomanipulation for the development of nanotechnology.
Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their components. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.
CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.
Applications of this approach in biological systems as well as in materials science will be described.
The merging of the features: - information and programmability, - dynamics and structural diversity, -constitution and selection, points towards the emergence of adaptive and evolutive chemistry.
References
Lehn, J.-M., Supramolecular Chemistry: Concepts and Perspectives, VCH Weinheim, 1995.
Lehn, J.-M., Dynamic combinatorial chemistry and virtual combinatorial libraries,Chem. Eur. J., 1999, 5, 2455.
Lehn, J.-M., Programmed chemical systems : Multiple subprograms and multiple processing/expression of molecular information, Chem. Eur. J., 2000, 6, 2097.
Lehn, J.-M., Toward complex matter: Supramolecular chemistry and self-organization, Proc. Natl. Acad. Sci. USA, 2002, 99, 4763.
Lehn, J.-M., Toward self-organization and complex matter, Science, 2002, 295, 2400.
Lehn, J.-M., Dynamers : Dynamic molecular and supramolecular
polymers,
Prog. Polym. Sci., 2005, 30, 814.
Lehn, J.-M., From supramolecular chemistry towards constitutional dynamic chemistry and adaptive chemistry, Chem. Soc. Rev., 2007, 36, 151.
Jean-Marie Lehnwas born in Rosheim, France in 1939. He received his bachelor's degree in Chemistry from the University of Strasbourg in 1960. There he also did research towards his doctorate with Guy Ourisson for three years, earning his Ph.D. in 1963. The following year he worked in the laboratory of Robert Burns Woodward at Harvard, where he participated in the total synthesis of vitamin B12. On his return to Strasbourg he began to work in areas at the interface between organic and physical chemistry, later taking an interest in biological processes as well.
In 1968, his research led to the fabrication of cage-like molecules that contain a cavity into which another chemical species of appropriate size and shape may be included, to form a “cryptate”, like a key fits into a lock. With this began his work on the chemical basis of "molecular recognition" (i.e. the way in which a receptor molecule recognizes and selectively binds a substrate), which also plays a fundamental role in biological processes. For these studies Lehn received the Nobel Prize in Chemistry in 1987 with D.J. Cram and C.J. Pedersen.
From 1970, Lehn has been Professor of Chemistry at the Université Louis Pasteur in Strasbourg and in 1979 he was elected to the chair of Chemistry of Molecular Interactions at the Collège de France in Paris.He retired from the Collège de France in 2010 and is presently Professor Emeritus at the University of Strasbourg, where he directs the Laboratory of Supramolecular Chemistry at the ISIS (Institut de Science et d'Ingénierie Supramoléculaires).
Over the years his work led to the definition of a new field of chemistry, which he has named "supramolecular chemistry" as it deals with the complex entities formed by the association of two or more chemical species held together by intermolecular forces, whereas molecular chemistry studies the features of the entities constructed from atoms linked by covalent bonds. His research broadened from molecular recognition towards supramolecular catalysis and transport processes. It also extended to the elaboration of functional devices, for supramolecular photonics, electronics and ionics.
Thereafter, the main line of development concerned the chemistry of “self-organization” based on the design of "programmed" systems that undergo spontaneous assembly of suitable components into well-defined functional supramolecular architectures, directed by the supramolecular processing of molecular information. More recently, importing into molecular chemistry, the dynamic features characteristic of supramolecular chemistry, through the introduction of reversible covalent bonds, allowed the implementation of selection in addition to design in self-organization processes. It led to the definition and development of “constitutional dynamic chemistry”, whose molecular or supramolecular entities are able to undergo reorganization in response to external stimuli, thus pointing to the emergence of an “adaptive chemistry”.
Author of more than 850 scientific publications, Lehn is a member of many academies and institutions and has received numerous international honours and awards.
Hosted by Colin Nuckolls
Meet the Speaker at 1:30pm in The Miller Seminar Room, 328
Havemeyer
Tea & Cookies at 4:00pm in The Miller Seminar Room, 328 Havemeyer
Seminar at 4:30 in Room 309 Havemeyer
***Reception to follow***
Biographical information can be found here: http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1987/lehn-autobio.html
