Introduction to the themed issue dedicated to Jean-Pierre Desvergne

It is with great pleasure that our journal, Photochemical & Photobiological Sciences, has devoted this special issue to Dr Jean-Pierre Desvergne in honor of his lasting contributions to the field of photochemistry and to its development. Jean-Pierre (Fig. 1) is originally from Cognac, a place whose name is synonymous with excellence in spirits and whose people are reputed for their quiet, thoughtful perfectionism. His friends and colleagues might also add a touch of stubbornness to this list, a quality that has served him well throughout his career. These qualities, along with a keen scientific acumen, contributed to Jean-Pierre's success when dealing with difficult research problems, such as demonstrating (back in the 1970s, when topochemical transformations were popular) that in fact it was crystal defects that were at the origin of the intermolecular photoreactivity of anthracene solids.¹ This work, done as collaboration between the photochemistry group of H. Bouas-Laurent (University of Bordeaux) and the group of Sir J. M. Thomas (University of Wales) was initiated while Jean-Pierre was a Leverhulme fellow in Thomas’ group. At the time, he was completing his PhD under the guidance of Prof. H. Bouas-Laurent on photochemistry and fluorescence in the solid-state, which he obtained in 1973. In 1971, Jean-Pierre became a CNRS (Centre National de la Recherche Scientifique) research fellow, and this foreshadowed his future career as a permanent CNRS researcher in Bordeaux.

Fig. 1 A young Jean-Pierre Desvergne thinks about his future as he prepares to work on his PhD thesis. Right: Long after obtaining his Ph.D., Jean-Pierre still looks to the future.

Upon joining the CNRS as a Research Associate in 1971, then Senior Research Associate in 1982, Jean-Pierre Desvergne began an illustrious scientific career that would take him to explore first the role of imperfections in the solid-state photoreactivity of molecular solids, then the photochemical synthesis of metal cation-binding species.² This interest in supramolecular photochemistry, which began in the mid-1970s, long before the widespread interest this field would come to life, led to one of Jean-Pierre's important contributions to the field and gave us the photo-induced switching of podands, crown ethers, and cryptands, along with intriguing new “jaw photochromic materials” and “semaphorenes”. As customary for Jean-Pierre, the studies were meticulously carried out and the mechanistic schemes he proposed were built on in-depth investigations of temperature, solvent, and binding effects.^3,4 Much of this work was based on the excited-state reactivity of anthracenes, which eventually led the Bordeaux group to be regarded as possessing extensive expertise on the topic, and to numerous collaborations with other well-established scientists. The effect of cation binding on the photophysical and photochemical properties of anthracenes naturally gave rise to various metal cation-sensing systems that culminated in the organization of an epic NATO series symposium (“Chemosensors of Ion and Molecule Recognition”, 1996) by Jean-Pierre and A. M. Czarnik, at the famous Château de Bonas in the French southwest.

It was in the process of instilling some modicum of solubility to anthracene photodimers that Jean-Pierre designed a series of anthracenes bearing long alkoxy chains in the remote C-2 and C-3 positions (so as to not hamper photodimerization). After a hair-raising synthetic sequence to obtain the desired compounds, he and an ERASMUS student discovered that these compounds would lead to the formation of gels at exceptionally low concentrations.⁵ The formation of fibrillar networks by small organic hydrocarbons devoid of hydrogen bonding or other specific molecular recognition units intrigued Jean-Pierre, who set out to find the origin for this spontaneous self-organization. Eventually, a relationship between the size and shape of the aromatic head group and the length and position of the hydrocarbon chains was found and this, along with crystal structure of a derivative able to form gels led to the formulation of a mechanism for the self-assembly of anthracene-based organogelators and the study of long-range energy transfer in these systems.⁶

As mentioned above, Jean-Pierre was also very active in the support of science, participating in the organization of numerous meetings (such as the highly successful 2004 ISOP meeting in Arcachon), committees, and filling various positions in French national scientific organizations. In particular, his efforts in the creation and direction (in 2007) of the Groupement d'Intérêt Scientifique “Materials in Aquitaine”, were fundamental in shaping chemistry in Aquitaine. For one, it gave the opportunity to fund blue-sky research by young researchers, but it also set the groundwork for what would later evolve into the larger Laboratoire d'Excellence on materials that would be awarded to the university. It is no surprise that Jean-Pierre is widely recognized for his contributions to the field, for which he received the Grammaticakis-Neumann Prize of the French Academy of Sciences in 2008 and is a Fellow of the Japan Society for the Promotion of Science (JSPS). This special issue is a tribute to Jean-Pierre's scientific career by his peers, and it is fitting that one may come across contributions covering very diverse areas of photochemistry from Asia, Europe, and North America. Jean-Pierre turned 65, but he is in great health and still very active. We wish him much more of the same success that accompanied his career and hope to have him share his advice and enthusiasm for photochemistry for many more years.

 

Dario M. Bassani, Editor

Jean-Luc Pozzo, Guest editor

Frédéric Fages, Guest editor

References

1. J.-P. Desvergne, J. M. Thomas, J. O. Williams and H. Bouas-Laurent, Role of imperfections in dimerization of substituted anthracenes. Part 1. 1,8-dichloro-9-methylanthracene, J. Chem. Soc., Perkin Trans. 2, 1974, 363–368.
2. J.-P. Desvergne and H. Bouas-Laurent, Cation complexing photochromic materials involving bis-anthracenes linked by a polyether chain – preparation of a crown-ether by photo-cycloisomerization, J. Chem. Soc., Chem. Commun., 1978, 403–404.
3. D. Marquis, J.-P. Desvergne and H. Bouas-Laurent, Photoresponsive supramolecular systems – synthesis and photophysical and photochemical study of bis-(9,10-anthracenediyl)coranands AAO_nO_n, J. Org. Chem., 1995, 60, 7984–7996.
4. G. Mcskimming, J. H. R. Tucker, H. Bouas-Laurent, J.-P. Desvergne, S. J. Coles, M. B. Hursthouse and M. E. Light, Photoinduced formation of a cryptand from a coronand: an unexpected switch in cation binding affinity, Chem.–Eur. J., 2002, 8, 3331–3342.
5. T. Brotin, R. Utermohlen, F. Fages, H. Bouas-Laurent and J.-P. Desvergne, A novel small molecular luminescent gelling agent for alcohols, J. Chem. Soc., Chem. Commun., 1991, 416–418.
6. A. Del Guerzo, A. G. L. Olive, J. Reichwagen, H. Hopf and J.-P. Desvergne, Energy transfer in self-assembled n-acene fibers involving ≥100 donors per acceptor, J. Am. Chem. Soc., 2005, 127, 17984–17985.

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