Concepts Characteristic of the Scientific Programme of SMC
What is SMC? The Larousse dictionary actually provides the following definition: it is a sub-discipline of chemistry which studies weak, non-covalent interactions between molecules. SMC is concerned with the complex entities formed by the association of two or several chemical species linked together by intermolecular forces, whereas molecular chemistry studies the properties of the entities made of atoms linked by covalent forces.
Jean-Marie Lehn was the first to lay its foundations and formalise its concepts in a seminal article published in 1978 (Lehn 1978). This work (especially the synthesis of cryptands performed in his laboratory
ten years earlier) earned him the 1987 Nobel Prize for Chemistry, which he shared with Charles J. Pedersen (DuPont) and Donald J. Cram (University of California, Los Angeles) ‘for their development and use of molecules with structure-specific interactions of high selectivity’.
SMC is a term coined by Lehn as the ‘“chemistry beyond the molecule”, bearing to the organised entities of higher complexities that result from the association of two or more chemical species held together by intermolecular forces’ (Lehn 1987). In an editorial published on the occasion of the 50th anniversary of Pedersen’s discovery, Lehn stated that he introduced the term SMC, ‘which is now widely accepted and has deeply permeated chemical literature, in order to define, consolidate and generalise the areas of crown ether chemistry, host–guest chemistry and the chemistry of molecular recognition, thus allowing for the emergence of the concepts and perspectives offered’ (Lehn 2017). As I will emphasise later, the vocabulary of the SMC stabilised quite late, while a small number of authors like Siegel (1996) or Dance (2003) still questioned its novelty and the usefulness of its concepts in the late 1990s.
Prominent aspects of Lehn’s work are its intense concern with chemical semiotics and its wide scope. As show in Table 2.1, this translates into a massive presence of the term ‘supramolecular’ and a large number of references in Lehn’s Nobel lecture compared to the other laureates.
Table 2.1 Number of occurrences of ‘supramolecular’ in the 1987 Nobel lectures of the three laureates In the late 1960s, a whole range of macro(poly)cyclic composites with spherical cavities were synthesised, and cryptands are now found in chemical product catalogues. After having explored the particular properties of these three-dimensional assemblies in catalysis and molecular recognition, for the transport of ions or molecules, Lehn and colleagues extended their research to the study of ‘supramolecular’ (a term introduced by Lehn in 1978) entities formed by self-organisation processes using molecular recognition to control and direct the spontaneous formation of complex architectures.
Supramolecular structures are a result of various noncovalent interactions, including electrostatic interactions, hydrogen bonding, van der Waals forces, hydrophobic interaction, coordination, etc., some of which are often cooperating in one supramolecular complex. More importantly, properties of the formed supramolecular complexes are far beyond summation of the individual components. The early 1990s saw the introduction of the notions of adaptation and evolution into chemistry, the extension of self-organisation processes to the selection of the species contributing to it, and the implementation of ‘informed’ chemical and dynamic diversity. Relying on the dynamic aspects of SMC (named ‘by essence’ a dynamic chemistry), Lehn proposed the definition of a general concept, covering molecular as well as supramolecular chemistry—that of Constitutional Dynamic Chemistry (CDC) which introduced a paradigm shift with respect to what he called constitutionally static chemistry (Lehn
2007).
Where does the specialty
stand today? Around 20 to 30 per cent of publications in leading chemistry journals such as Angewandte Chemie, Chemical Communications, Chemistry: A European Journal, and The Journal of the American Chemical Society
are concerned with the practical achievements arising from concepts and visions that have been developed in this domainFootnote 14 (Diederich 2007). There are currently two facets to the specialty
: one is oriented mainly towards synthesis, attempting to design constructions with given molecular bricks, while the other seeks to explain, understand, and partly control existing self-assemblages. The rise of SMC has also been accompanied by a development of new concepts and methods able to monitor the sometimes quite fast dynamics of supramolecular systems. With this, SMC has become fruitful also for other areas in chemistry.
A Three-Period Chronology
As with other specialities (see McCray (2005) on the existence of ‘creation stories’ that reconstruct the development of a particular idea or invention back to a singularity), SMC comes with narratives about its leaders and ‘founding fathers’. In their textbook
‘Supramolecular Chemistry
’, Steed and Atwood (2009) trace its roots to the early days of modern chemistry. In this study, I chose to start in the year of Jean-Marie Lehn’s first publications (1961) and cover a period of 50 years.
Jean-Marie Lehn is a prolific author (nearly 900 publications between 1961 and 2011), whose articles have been frequently and progressively cited to this day.Footnote 15 Using co-authorship as a proxy for collegiality
(Laudel 2002; Larivière et al. 2016), his co-publications profile is reproduced with the ‘Demography’ module of the CorText Manager tool. The module analyses a .txt file built from a Web of Science request (set of 897 publications released between 1961 and 2011 (Noël 2019), 488 co-authors, number of co-authored publications ≥2).Footnote 16 Lehn’s co-publications profile (Fig. 2.1) identifies a set of co-authors, with whom he has primarly published (49 names are extracted from a list of 488 co-authors). Their names and profiles are shown in different colours; for instance, on the left hand side of the graph one can see Ourisson’s (Lehn’s supervisor) contribution in yellow.
This profile features some interesting elements: first, there is an increase in the pace of co-authored publications at the turn of the 1990s (the slope, which seems quite stable since 1966, suddenly increases). This is probably related to the ‘Nobel effect’ but is also emblematic of the growing importance of teamwork and the increasing division of labour in contemporary chemistry (Cronin et al. 2004). Second, co-authors diversify in the most recent period: they are more numerous and different from those of the previous ones.
Based on slope variations of the profile, I have identified three periods of almost equal duration.
Period 1: The Emergence of the Supramolecular Chemistry Paradigm (1961–1978)
The 1960s, when Lehn entered the University, were a time of rapid growth of synthetic organic chemistry. After a thesis on triterpene NMR obtained under Ourisson’s supervision, Jean-Marie Lehn left for a year to do a post-doc at Harvard, where he took part in the total synthesis of vitamin B12 (the most complex natural product synthesised to date), finally completed in 1971. Like so many other chemists of this period, Lehn was actively engaged in research related to organic synthesis. He participated in this landmark work in the history of organic chemistry that represented in his eyes ‘the modern apogee’ (Lehn 1980) since it showed that organic chemists were able to create very complex molecules by forming covalent bonds (Woodward 1973).
Upon his return from Harvard in 1964, Jean-Marie Lehn went to Strasbourg and entered the CNRS to create his own laboratory
. He had become a recognised specialist in the use of NMR for understanding the physical properties of organic molecules. Searching for themes different to those he had studied with Ourisson and Woodward, he decided to direct his research towards physical chemistry. NMR studies of the movements of a liquid’s molecules ensued. In parallel, he developed an entirely theoretical theme in his group
: ab initio calculations of structural and conformational properties (Lehn in Kleinpeter and Eastes 2008).
In 1966, Lehn’s interest turned to ‘how a chemist
might contribute to the study of … highest biological functions’ (Lehn 1987, p. 448). In this context, the first synthesis of crown ethers performed by Pedersen, an engineer
for DuPont in 1967, supported his idea that it was possible for a cage molecule (which has a cavity) to capture another molecule with a complementary form. This led to the development of the chemistry of cryptands and cryptates in his laboratory
.
The first cryptand was synthesised in September 1968 by two researchers doing their PhDs—Jean-Pierre Sauvage and Bernard Dietrich. It had been theoretically designed by Lehn by taking into account the little information available at that time on the complexation and transport of alkali metal ions by natural ionophores. It was a cage molecule, capable of selectively fixing a chemical substance (of the appropriate shape and size, in this case a potassium ion) in its cavity, called a crypt. The cryptand (from the Greek word kryptos meaning hidden) was a new molecular object, with a bond between the potassium ion and the crypt which had nothing to do with the covalent bond. Even though the first cryptand was synthesised ‘by chance’ (as mentioned in the closing lecture on 4 June 2010Footnote 17 at the Collège de France
), this situation was not artificial. The first direct proof of the cryptands’ structure
was provided by Raymond Weiss, professor at the University of Strasbourg since 1957, using X-ray diffraction techniques.Footnote 18 In the following years the power of the concept of ‘molecular recognition’ and its generality were demonstrated.
Although Lehn made an effort to clarify terms in his 1978 publication, his definition of SMC remained unclear. Mullins (1972) sees this as a condition of emergence, the paradigm being an object to be adjusted and specified under new or stricter conditions.
For his part, Donald J. Cram at UCLA recognised that the work of C.J. Pedersen provided [him/them] ‘an entree into a general field’ (Cram 1987, p. 419). In his Nobel Lecture (1987, p. 419), he said: ‘Although we tried to interest graduate students in synthesizing chiral crown ethers from 1968 on, the efforts were unsuccessful. In 1970 we insisted that several postdoctoral co-workers enter the field’. By 1974, he published (with his wife, Dr. Jane M. Cram) a first general article entitled ‘Host-Guest Chemistry’ summarising their thoughts, methods, and results (Cram and Cram 1974). Along their definition, hosts are synthetic counterparts of the receptor sites of biological chemistry and guests the counterparts of substrates, inhibitors, or cofactors. He and his colleagues designed and prepared more than 1000 hosts, each with unique chemical and physical properties (Cram and Cram 1994). Cram underscored the importance of visualisation and the use of Cory-Pauling-Koltun (CPK) molecular models that provide better insights than the usual graphs, tables, and figures.
Period 2: The Emergence of a Specialty
: From Supramolecular Chemistry to a Science of Supramolecular Systems (1979–1997)
The second period (1979–1997) consisted of two phases: the network phase followed by the cluster phase. In the network phase, certain participants recruited students. In groups of two or three, the scientists began to homogenise their vocabulary, to build fragments of a paradigm: the term ‘molecular machine’ was fully discussed for the first time in an article by V. Balzani,Footnote 19 J. Fraser Stoddart, and collaborators in 1993. They also built new resources which contributed to the dynamic of their relationships: textbooks and curricula, originally written in mother tongue, became key components of the educational agenda.Footnote 20 A host of collaborations developed and gave rise to co-publications. In 1987 Vincenzo Balzani gathered contributions (including those of Lehn and Pedersen) collected in a workshop on Capri Island in a textbook
entitled ‘Supramolecular Photochemistry’. Beyond Strasbourg, Lehn’s network extended to colleagues at Collège de France (notably J.-P. Vigneron) where he was appointed in 1979, a position that gave him prestige and time to do research. The radial structure
around Lehn expanded to form crosscutting branches between his former students and foreign colleagues—for instance M.W. Hosseini and R. Ziessel co-authored publications with V. Balzani. For their part, J.-P. Sauvage and B. Dietrich entered the CNRS in 1971 and 1974, respectively. The Strasbourg group
has been able to stabilise, to develop, and recruit new members. Sauvage has developed his own line of research from 1983 onwards.
Mullins
stresses the importance of the Cold Spring Harbor summer school as the ‘melting pot’ site. Part of the group
(Atwood
and Stoddart) considered the founding conference to have been the one organised in Jachranka
, close to Warsaw in Poland. Although the 50 participants were overwhelmingly European, neither Jean-Marie Lehn nor his group
was present. Jerry Atwood commented:
There was a key meeting in Poland in 1980 and that meeting formed the basis for the development of the field of supramolecular chemistry. It was one of those meetings where I knew no one when I went there; all of us came from different areas and in that week I made many of my best friends.Footnote 21
In the cluster phase, decisive changes took place. There was a shift from network to a collective entity recognised and constituted as such by its members. The community
produced a shared directory of resources: French and German textbooks were translated into English. This was the time of the creation of journals specifically dedicated to SMC (featuring programmatic editorials), some of them short-lived: the Journal of Inclusion PhenomenaFootnote 22 in 1983, Supramolecular Chemistry
in 1992. Atwood organised a board of editors that ultimately produced an eleven-volume set (197 chapters, 6672 pages) which covered the gamut of this rapidly expanding area of research (Comprehensive Supramolecular Chemistry
, Pergamon Oxford, 1996). For his part, Jean-Marie Lehn published Supramolecular Chemistry
: Concepts and Perspectives in 1995.Footnote 23
Initiatives abounded, as the list of symposia on (and surrounding) SMC attests (Table 2.2). The topics covered include liposomes as well as nanogels or surface science. On that list we also find the first international summer school (a place where students were trained) organised in Strasbourg in 1990. The regular training of students presupposed the existence of job opportunities.
Table 2.2 List of symposia on and surrounding SMC (1988–1997), extracted from the Memorandum of Understanding for the implementation of a European Concerted Research Action designated as COST Action D11a The group
began to equip itself with more formal means of communication, thereby becoming a specialty
. The resources created became increasingly collective and consubstantial with the group
’s existence: volume 11 of the manual mentioned above (Comprehensive Supramolecular Chemistry
) is a cumulative subject index, further aiding the location of specific pieces of information. Between 1981 and 2000, Lehn himself devoted time to extended stays at European universities (as visiting professor in Cambridge, Barcelona, Frankfurt, Karlsruhe, Oxford, etc.) and at Harvard. His co-authorship pattern is much more diverse (particularly in the cluster phase as shown on Fig. 2.1) than it was before 1978.
Around 1996 the specialty
stabilised. With the support of chemical learned societies, Jean-Marie Lehn created Chemistry: A European Journal, which became the main forum for SMC advances. Chemistry also stands out due to its ‘concepts’ section hosted since September 1996. One of the main aims of Chemistry was to highlight and support the outstanding research produced by groups across Europe.
As part of the European programme COST-chemistry, facilitated by a chemist
from Toulouse, the D11 actionFootnote 24 was launched in 1998, with funding that boosted the Strasbourg teams.
Period 3: Institutionalisation Processes (1998–2011)—Materialising Concepts
The third period was the post-Nobel Prize and institutionalisation period. Scientists moved from a project
with an initial research question to another. Jean-Marie Lehn worked on many topics that shared one core research question: ‘what does SMC mean?’. He endeavoured to materialise the concept of SMC in its successive senses and devoted part of his efforts to ensuring the long-term survival of the bodies created: the Supramolecular Science and Engineering Institute and the thematic network of advanced research (RTRA).Footnote 25 He was involved in many and diverse collaborations and travelled extensively.
In December 2011, ISIS
counted nine laboratories and four industrial branches. This original structure
is constituted of senior laboratories, headed by recognised and internationally renowned scientists, and junior laboratories, where researchers beginning their career develop independent research as part of a project
that is not scheduled to last more than six years. ISIS
stands out in the French research ecosystem: the recruitment of foreign professors on the international market concurs with the strong local roots of this organisation
.
In 1987, Jean-Marie Lehn defined SMC as the ‘chemistry beyond molecules’. It is a polysemic object, both a concept and a specialty
, even a discipline, with the main characteristic of being situated ‘at the borders of’. That is in fact the name (in French) of the RTRA (the Centre International de Recherche aux Frontières de la Chimie which has been translated as International Centre for Frontier Research in Chemistry).
An Original Conceptual and Organisational ‘Heritage’
Which social processes encouraged the emergence of this specialty
in Strasbourg? Based on my fieldwork and historical documents, I list a few of them, looking for patterns of a general scope.
A Polymorphic, Though Coherent and Organised Community
, Attentive to Its Position
From both inside and outside, chemistry is perceived as a coherent and organised entity: the multiple stories researchers shared collectively (from the awarding of the Nobel Prize to the national competition
for RTRA) have nurtured the disciplinary framework. As Lehn mentioned in his Nobel Lecture, chemists in Strasbourg, as a whole, contributed to the Prize:
I wish to thank very warmly my collaborators at the Université Louis Pasteur in Strasbourg and at the College de France in Paris whose skill, dedication and enthusiasm, allowed the work described here to be realized. Starting with B. Dietrich et J.-P. Sauvage, they are too numerous to be named here, but they all have contributed to the common goal. (Lehn 1987, p. 484).
The community
as a whole derived benefits from these successes. Today, the chemistry department (Faculté de Chimie) offers a wide range of specialties. As expressed by a high-level person with policy-making responsibilities at CNRS, ‘it’s a mosaic’.Footnote 26 But for an executive head of the university,
compared to other disciplines, chemistry is easy to position: there are industrial partners, it has a good image within society
… a strong symbolic value
with Jean-Marie Lehn. This introduces strong subjective elements, other than the quality of the person, the quality of the science which is done. It’s simple with respect to the outside world. In communication efforts, when I say ‘Jean-Marie Lehn Nobel Prize’, it’s very easy!Footnote 27
This symbolic dimension has been undoubtedly strengthened by awarding the Nobel Prize to other chemists from (or affiliated with) Strasbourg whose work is more or less connected to that of Lehn and SMC.Footnote 28 The quotation above shows that, despite the epistemic diversity of the department (a mosaic), the disciplinary framework created and creates a sense of unity. A sense of allegiance to chemistry, a characteristic of the discipline emphasised by Lenoir (1997, pp. 48–49), was coupled earlier in Lehn’s discourse with attention to its centrality: ‘Chemistry plays a central role both in the natural sciences and in knowledge, and in its economic
importance and omnipresence in our daily lives’ (Lehn 1980, emphasis by the author). This positioning practice of chemists, referring to chemistry as the central science, persists until today (Bertozzi 2015). It is not specific to Strasbourg but has undoubtedly been taken up in the emergence of SMC.
A Strong Local Rootedness with Great International Openness
The University’s international openness can be rooted in its history (Craig 1984; Olivier-Utard 2010; Crawford and Olff-Nathan 2005). Following the annexation of Alsace-Moselle by Prussia, authorities encouraged the recruitment of foreign teachers from 1871 onwards. This was also the case after World War I, when Alsace came back under the auspices of the French State. A professor explained:
For more than 150 years, the University appeared to be sometimes French, sometimes German, sometimes French.… In its relation to Germany, France considered the University as a ‘showcase’ and the other way round. There are always been a recruitment of quality people. Since these early periods, people have been carefully selected to import researchers coming from abroad who settled here in Strasbourg.Footnote 29
The aim was to build an exceptional setting, which remained extraneous to the local people and required a number of years to fully appropriate. As many testimonies collected during the fieldwork attested, there is still a large incongruity between foreign and locally-trained professors (the latter constituting a large part of interviewees in our sample). For instance, the need for teaching in French at the undergraduate
level creates a clear differentiation
in terms of access to master’s programmes, which has been described as problematic by interviewees.
In addition to these features came the development of institutional structures (first the ISIS
, then the RTRA) supported by stakeholders, especially in the Alsace Region.Footnote 30 The Strasbourg members of the ‘paradigm group
’ (almost all are members of the French Académie des Sciences) embedded knowledge within a political dimension, which gave it the power of both a social and a symbolic link (Jacob 2007). The Alsatian local rootedness translates into the capacity to act in and at the service of the region as well as at the local, national, and international level. The career of Guy Ourisson, the ‘ultimate godfather of Strasbourg chemistry’,Footnote 31 is emblematic thereof.
The ISIS
Building as a Mediator Between Epistemic Practices and Politics
In the late 1990s Lehn created the Supramolecular Science and Engineering Institute (Institut de Science et d’Ingénierie Supramoléculaire, ISIS
), which was hosted in a new building from 2002 onwards. This institute was specifically designed for the further development of his research, based on a vision
he himself had defined: that of a scientific project
incubator
, where ‘the most brilliant young researchers in the supramolecular sciences will be able to express themselves freely, before pursuing their career in other research centres’.Footnote 32 This new institute signified a major achievement in his career and was thought of as an organisational innovation in the French research scene. It was supported by the Louis Pasteur University in partnership with the CNRS and funded by the local government.
The entrance hall of the five-story building (Fig. 2.2) bears a plate with the engraving ‘ISIS
is the project
of Jean-Marie Lehn, Nobel Prize for Chemistry, supported by the Louis Pasteur University in partnership with the CNRS’.
Such personalisation is quite rare in the world of French research. In a report to the Alsace Region in 1990,Footnote 33 Guy Ourisson noted that
chemistry research in Alsace presents very particular characteristics, which need to be properly identified in order to understand that the level of this research is not a result of Jean-Marie Lehn receiving the Nobel Prize, but the reason why this Nobel Prize was possible, without him having to leave the country!
The ISIS building was designed by the French architect Claude Vasconi (1940–2009). Vasconi was born in the same city as Lehn and was of the same generation
. He graduated from the Ecole Nationale Supérieure des Arts et de l’Industrie in Strasbourg. ISIS’ architecture was jointly designed with two purposes: first, priority was given to the horizontal circulation in a volume organised around a central atrium in order to meet a strong demand for decompartmentalising disciplines. As for a whole generation
of science architecture
in the 2000s (Yaneva 2010), the atrium became an important interactive space (a connecting mechanism, ibid., p. 143). The building invited the creation of new types of associations among researchers from different (sub-)disciplines or specialties and among public research and industry
. A senior professor summarised it in this form:
A specialist in a discipline, a related area [to SMC], a platform. Four platforms and a fifth for common machines, this was [Jean-Marie Lehn’s] concept.Footnote 34
Second, ISIS was also conceived of as a ‘transient’ structure, where independent young researchers could work before they gained a permanent position in the academic system. The concept was that of a space where ‘mobile professors’ work/compete with each other. This particular setting refers to a phase in the researchers’ careers rather than to the substance of their work (Normark 2015).
Based on Strasbourg’s experience, public research organisations (e.g. CNRS, INSERM) and universities encouraged the creation of such ‘research hotels’ (hôtels à projets) in France. In Bordeaux, the European Institute of Chemistry and Biology (Institut Européen de Chimie et de Biologie, IECB
) was built with a specific reference to Lehn’s project
. The local authorities provided support, as had happened in Alsace, and the IECB
opened in 2003. The ‘research hotels’ model has since experienced ups and downs: the issue of incongruity between ‘local’ and foreign researchers that benefit from the provided resources to different degrees was also raised by an interviewee in Bordeaux.