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Biological molecular machines enable chemical transformations, assembly, replication and motility, but most distinctively drive chemical systems out of-equilibrium to sustain life1,2. In such processes, nanometre-sized machines produce molecular energy carriers by driving endergonic equilibrium reactions. However, transforming the work performed by artificial nanomachines3–5 into chemical energy remains highly challenging. Here, we report a light-fuelled small-molecule ratchet capable of driving a coupled chemical equilibrium energetically uphill. By bridging two imine6–9 macrocycles with a molecular motor10,11, the machine forms crossings and consequently adopts several distinct topologies by either a thermal (temporary bond-dissociation) or photochemical (unidirectional rotation) pathway. While the former will relax the machine towards the global energetic minimum, the latter increases the number of crossings in the system above the equilibrium value. Our approach provides a blueprint for coupling continuous mechanical motion performed by a molecular machine with a chemical transformation to reach an out-of-equilibrium state.

The digital revolution sets a milestone in the progressive miniaturization of working devices and in the underlying advent of molecular machines. Foldamers involving mechanically entangled components with modular secondary structures are among the most promising designs for molecular switch‐based applications. Characterizing the nature and dynamics of their intramolecular network following the application of a stimulus is the key to their performance. Here, we use non‐dissociative electron transfer as a reductive stimulus in the gas phase and probe the consecutive co‐conformational transitions of a donor‐acceptor oligorotaxane foldamer using electrospray mass spectrometry interfaced with ion mobility and infrared ion spectroscopy. A comparison of collision cross section distributions for analogous closed‐shell and radical molecular ions sheds light on their respective formation energetics, while variations in their respective infrared absorption bands evidence changes in intramolecular organization as the foldamer becomes more compact. These differences are compatible with the advent of radical‐pairing interactions., Gas‐phase non‐dissociative electron transfer is used for charge reduction of a donor‐acceptor oligorotaxane foldamer (green). The consecutive co‐conformational transition is monitored using ion mobility spectrometry and infrared ion spectroscopy. Comparing the collision cross section distributions (blue) and infrared spectra (red) recorded for analogous closed‐shell and radical systems highlights differences that can be attributed to radical‐pairing interactions.

Recent literature provides increasing samples of structural studies relying on ion mobility coupled to mass spectrometry in view of characterizing gas-phase conformation and energetics properties of biomolecular ions. A typical framework consists in experimentally monitoring the collisional cross sections for various experimental conditions and using them as references to select appropriate candidate structures issued from theoretical modeling. Although it has proved successful for structural assignment, this process is resource costly and lengthy, namely due to intricacies in the selection of appropriate input geometries. In the present work, we propose simplified methodologies dedicated to the systematic screening of ion mobility data acquired on systems built from repetitive subunits and detail their application to challenging artificial molecular switch systems. Capitalizing on coarse-grained design, we first demonstrate how the assimilation of subunits into adequately assembled building-blocks can be used for fast assignments of a system topology. Further focusing on topology-specific differential ion mobility trends, we show that the building-block assemblies can be fused into single fully convex solid figure models, i.e., sphere and cylinder, whose projected areas follow a two-parameter power formalism

State-of-the-art characterization of proteins using MS namely relies on fragmentation methods that allow exploring featured dissociative reaction pathways. These pathways are often initiated by a series of potentially informative mass-constant conformational changes that are nonetheless frequently overlooked by lack of adequate investigation techniques. In the present study, we propose a methodology to readily address both structural and energetic aspects of stereoisomerization reactions using ion mobility coupled with MS. To this end, a commercial spectrometer was used as a reactor comprising an energy resolved collisional activation step intended at promoting controlled conformational changes and a structural assignment step dedicated to the identification of the generated isomers. This identification relies on ion mobility and other on-line coupled techniques, namely an originally designed gas-phase H/D exchange experiment. We here apply this methodology to characterize the isomerization kinetics of capistruin, a 19-residue long lasso-folded peptide. We expect this approach to bring insights into the physical origin of global dissociation thresholds monitored in MS/MS experiments and to set a promising basis for quantitative investigations of the stability of different molecular folds.

International audience; Traveling wave ion mobility spectrometers (TW IMS) operate at significantly higher fields than drift tube ion mobility spectrometers. Here we measured the fragmentation of the fragile p-methoxybenzylpyridinium ion inside the TW ion mobility cell of the first-generation SYNAPT HDMS spectrometer. The ion’s vibrational internal energy was quantified by a vibrational effective temperature Teff,vib, which is the mean temperature of the ions inside the cell that would result in the same fragmentation yield as observed experimentally. Significant fragmentation of the probe ion inside the TW IMS cell was detected, indicating that field heating of the ions takes place in TW IMS. For typical small molecule IMS conditions, Teff,vib = 555 ± 2 K. The variations of the effective temperature were studied as a function of the IMS parameters, and we found that Teff,vib decreases when the wave height decreases, when the pressure increases, or when the wave speed increases. The energy transfer efficiency of argon is higher than for He, N2 or CO2. Teff,vib being directly related to the ion speed inside the TW IMS, our results also provide new insight on the ion movement in TW IMS. We also discuss the influence of field heating of ions for calibration and structural studies in TW IMS.

Morsa Denis. Compte rendu de la réunion du samedi 13 mars 2004.. In: Revue belge de philologie et d'histoire, tome 82, fasc. 4, 2004. Histoire médiévale, moderne et contemporaine - Middeleeuwse. moderne en hedendaagse geschiedenis. pp. 1203-1209.

Urbanization of Belgium (1500-1800). Size, Hierarchy and Dynamics of the Towns. The urbanization of Belgium in the Modern Times is in no way an unknown territory. On the contrary, this field was recently the object of significant advances. However the research that has been carried out has not exhausted the subject. For example, an operational list of the Belgian communities regarded as towns between 1500 and 1800 is still lacking. And the urbanization process has not yet been examined from the angle of systemics. These observations led us in a first stage to draw a list of the Belgian towns of the modern period. Then this data base was used to understand the dynamics of the cities. Through the prism of the distribution of the towns according to their size, through rank-size adjustments, through a modelling of town generation and the use of allometric coefficients, one observes that the logic that presided over the organization of the urban network is completely altered in the XVIIIth century. From now on, the extension of the system no longer relies on the development of the more populated units (> 20,000 inhabitants) but, on the opposite, feeds on the growth of the towns situated in the intermediate to lower ranks of the hierarchy. This phenomenon can be tied to the process of « ruralization » of manufacturing taking place principally in the provinces of western and eastern Flanders. The analysis also reflects the insufficient integration of the Belgian space in the XVIth-XVIIIth centuries, period in which coexist sub-systems imperfectly interlocked. The urban outlook of Belgium in the modern period reflects the picture of a splintered country that renounced to organize itself around a metropolis of large dimensions. In short, the urbanization process of Belgium under the Ancien Régime owes much to economic and political factors., L'urbanisation de la Belgique au cours des Temps modernes ne constitue pas un thème inédit. Au contraire, le sujet a bénéficié récemment d'avancées significatives. Toutefois, les travaux qui se sont succédé sont loin d'avoir épuisé la matière. Par exemple, une liste opérationnelle des localités belges considérées comme villes entre 1500 et 1800 manque toujours à l'appel. D'autre part, le processus d'urbanisation n'a guère été examiné à l'aune de la systémique. Ces constats nous ont incité dans une première étape à dresser le répertoire des villes belges de l'ère moderne. Ensuite, on a exploité la base de données afin de saisir la dynamique des villes. A travers le prisme des distributions des villes selon leur taille, des ajustements rang-dimension, du modèle des générations de villes et des coefficients d'allométrie, on observe que la logique qui présidait à l'organisation du système urbain se modifie dans une mesure radicale au XVIIIe siècle. Désormais, l'extension du système ne procède plus de l'essor des unités les plus peuplées (> 20 000 habitants) mais au contraire s'alimente de la poussée des localités situées aux rangs intermédiaires et inférieurs de la hiérarchie. Le phénomène se rattache à la « ruralisation » de l'industrie dont principalement les provinces de Flandre orientale et occidentale font l'expérience. L'analyse reflète également l'intégration insuffisante de l'espace belge aux XVIe-XVIIIe siècles, au sein duquel coexistent des sous-systèmes imparfaitement emboîtés. La configuration urbaine de la Belgique à l'époque moderne renvoie l'image d'un pays éclaté qui a renoncé à se centraliser autour d'une métropole de grandes dimensions. Bref, le processus d'urbanisation de la Belgique sous l'Ancien Régime est largement tributaire des facteurs économiques et politiques., De ver stedelij king van België (1500-1800). Omvang, rangorde en dynamiek van de steden. De ver stedelij king van België in de moderne tijd is geen onontgonnen onderzoeksgebied. In de voorbije jaren is er juist op dat vlak heel wat vooruitgang geboekt. Toch kan men niet zeggen dat deze materie nu uitputtend behandeld is. Zo ontbreekt er nog altijd een handzame lijst van de plaatsen die men in de betreffende periode als steden kan beschouwen. Het verstedelijkingsproces is nauwelijks volgens een bepaald systeem onderzocht. Dat heeft er ons toe gebracht allereerst een lijst op te steilen van de Belgische steden in de moderne tijd. Daarna werd de gegevensbank gebruikt om de dynamiek van de steden te vatten. Via een opdeling van de steden naar formaat en rangorde, naar het generatiemodel en allometrische coefficienten, kan men vaststellen dat de logica van de organisatie van het stedelijk systeem op een radikale manier gewijzigd wordt in de XVIIIde eeuw. Van dan af is de uitbreiding geen gevolg meer van de opgang van de meest bevolkte eenheden (meer dan 20 000 inwoners), maar van plaatsen die een lagere of middenplaats in de hiérarchie bekleden. Dat fenomeen is verbonden met de « ruralisatie » van de industrie die vooral zichtbaar is in de provincies Oosten West-Vlaanderen. Uit de analyse blijkt ook de onvoldoende integratiegraad van de Belgische ruimte in de XVI-XVIIIde eeuw, waarin subsystemen naast elkaar blijven bestaan zonder wederzijdse aanpassing. Het beeld van verstedelijkt België in de moderne periode toont een verdeeld land dat zich niet gericht heeft op een enkele grote stedelijke kern. Kortom, het urbanisatieproces van België tijdens het Ancien Régime hangt nauw samen met economische en politieke factoren., Morsa Denis. L'urbanisation de la Belgique (1500-1800). Taille, hiérarchie et dynamique des villes.. In: Revue du Nord, tome 79, n°320-321, Avril-septembre 1997. pp. 303-330.

Morsa Denis. Une croissance manquée : Huy (1600-1800). Quelques hypothèses sur un effondrement économique. In: Revue belge de philologie et d'histoire, tome 59, fasc. 2, 1981. Histoire médiévale, moderne et contemporaine — Middeleeuwse, moderne en hedendaagse geschiedenis. pp. 325-381.

Denis Morsa. Small towns in the principality of Liège at the end of the 18th century. First approaches. This analysis of small towns in the principality of Liège at the end of the 18th century is an attempt to contribute to the study of the problems of urbanization in Western Europe. It is divided in several steps: the definition of criteria to distinguish small towns from areas and villages inhabited by country people, the evaluation of the popupation of the entities described, the use of precise statistical processes to check the correspondence of the Liège urban structure to some distribution types or normative hierarchies. This approach throws a new light on two essential elements of the rban net in the region of Liège: immaturity and general lack of balance., Denis Morsa. Les petites villes dans la principauté de Liège à la fin du XVnie diècle. Premières approches. En étudiant les petites villes dans la principauté de Liège à la fin du XVIIIe siècle, il s'agit d'apporter une contribution à la problématique de l'urbanisation en Europe occidentale. L'analyse progresse en plusieurs étapes : mise au point d'une critériologie pour distinguer les petites villes des agglomérations et communautés d'habitants du plat-pays ; évaluation des effectifs de la population des localités prises en compte ; mise en oeuvre de procédés statistiques explicitement définis afin de tester le degré de conformité de l'armature urbaine liégeoise par rapport à certaines distributions types ou à des hiérarchies normatives. Cette démarche met en lumière deux composantes essentielles du réseau urbain liégeois : immaturité et déséquilibre d'ensemble., Morsa Denis. Les petites villes dans la principauté de Liège à la fin du XVIIIe siècle. Premières approches. In: Histoire & Mesure, 1987 volume 2 - n°2. Varia. pp. 73-91.

Morsa Denis. Salaire et salariat dans les économies préindustrielles (XVIe-XVIIIe siècle). Quelques considérations critiques. In: Revue belge de philologie et d'histoire, tome 65, fasc. 4, 1987. Histoire - Geschiedenis. pp. 751-784.

Salamagne Alain. Philippe II de Croÿ et la fortification des villes de Hainaut : Avesnes, Bouchain, Le Quesnoy, trois chantiers renaissants de la décennie 1530. In: Revue belge de philologie et d'histoire, tome 89, fasc. 2, 2011. Villes et villages : organisation et représentation de l’espace. Mélanges offerts à Jean-Marie Duvosquel à l’occasion de son soixante-cinquième anniversaire et publiés par Alain Dierkens, Christophe Loir, Denis Morsa, Guy Vanthemsche. pp. 685-700.