The aim of the project is to synthesize new 1,1,4,4-tetracyanobutadienes (TCBDs) from ynamides possessing the "aggregation induced emission" (AIE) property. The synthetic pathway towards this kind of compounds, which has recently been developed by the team of the scientific coordinator, consists in a sequence of [2+2]cycloaddition followed by a [2+2]retroelectrocyclization between tetracyanoethylene and ynamides. This method is tolerant to many functional groups and generally leads to TCBDs in high yields. Compounds that have the AIE property exhibit fluorescence in the solid state (potentially as nano-aggregates dispersed in a liquid) but not in solution. This property comes from the restriction of the internal molecular movements (rotation, vibration) that allows for the radiative deactivation of the excited state, which is impossible when the molecule possesses "too many" degrees of freedom (non-radiative deactivation in this case). TCBDs that do not come from ynamides are generally not fluorescent at room temperature, neither in the solid state nor in solution. Consequently, this project would raise a new family of compounds having this remarkable property. Moreover, the emission maximum of the AIEgen TCBDs recently synthesized in our laboratory is located beyond 600 nm, which allow for biological applications since it does not compete with the natural autofluorescence that is encountered in living organisms. Once the best emitters identified and characterized, two potential applications will be studied in order to take advantage of the restoration of the fluorescence of the TCBDs in strained medium. First, they will be made water-soluble in order to incorporate them into artificial membranes formed with a Langmuir trough, which would thus allow for their visualization by fluorescence. Given that the emission maximum of our TCBDs is very sensitive to the surrounding medium, one can imagine that this maximum could also be sensitive to the pressure applied to the membrane. In this case, it would constitute one of the first pressure sensors at the molecular level. Finally, these TCBDs will be linked to substrates specific of some proteins such as sugar derivatives, which could allow for their specific visualization in vitro. Whether it be for working on membranes or be it on proteins, TCBDs could be linked to water-soluble groups by "click" chemistry from a common propargylic synthon for the these two applications.

Molecular electrophilic regions observed at halogen (Hal), chalcogen (Chalc) and pnictogen (Pnic) atoms, also called Sigma-Holes, are preferential anchored sites targeted by molecular partners bearing nucleophilic groups. Interactions involving Sigma-Holes are highly directional, while the intensities are controlled by the electrophilic/nucleophilic interactions. In the context of Supramolecular Chemistry, Crystal Engineering and Material Science, sigma-hole interactions, are much less understood than hydrogen-bonding interactions, and therefore have been less used. The use of strong and directional intermolecular interactions is of main importance in those fields of research because, driving the molecular organization in the space, sigma-hole interactions can control the properties of supramolecular entities and materials through the structure-properties relationship. To this end, we will focus on the analysis of the electron density distribution, in particular in the intermolecular regions they are involved. In the design of sigma-hole interactions, three key points are main objectives in the project. First, the strengthening of such interactions will be investigated by (i) introduction of electron withdrawing groups, (ii) co-crystallization with Lewis bases of enhanced basicity, and (iii) the conception of cooperative systems driving main electrophilic…nucleophilic forces in the building of the crystalline space and permitting the design of novel supramolecular motifs. Second, while the electrophilic sites of sigma-holes are placed along specific molecular directions depending on the Hal, Chalc and Pnic hybridizations, they are a priori enhanced in all molecules when heavier atoms of their respective series are used. Accordingly, the synthesis of molecules bearing heavier atoms of these families permits to generate directional intermolecular electrophilic….nucleophilic interactions with increased interaction energies along specific directions. Third, the modification of intermolecular forces driving the crystalline building will permit the tuning of associated properties, such as for instance fusion enthalpies and charge transfer between molecules (either by electronic or atomic transfer). The project gathers together two complementary research groups in Nancy (PI) and Rennes, collaborating in the field since 2007. In addition to the research already carried out with sigma-hole interactions involving halogen bonding, we have also initiated together the investigation of chalcogen bonding. Thus, in a recent paper dealing with accurate low-temperature high-resolution X-ray diffraction measurements and ab initio quantum calculations of the selenium sigma-hole in selenophtalic anhydride, we have demonstrated that chalcogen and halogen bonding can drive different geometrical preferences of molecular packing. Furthermore, during this last year, we also identified that organic selenocyanates actually have a very strong tendency to self-associate in the solid state through short N•••Se interactions. These structures indicate that the selenocyanate group can actually be a very efficient chalcogen bond donor group, for its implementation in Crystal Engineering strategies, as planned in the present project. Concerning the much less explored pnictogen bonding, sigma-holes can also appear along Pnic-series, provided these atoms bear at least one electron-withdrawing group. Accordingly, we will design and prepare systems adapted for in-depth analysis of the electron density, both theoretically and experimentally, concentrating first on phosphorus based model molecules. The consortium presents a complementary approach in the project. Thus, while synthesis and crystal growth will be carried out in Rennes, the analyses of experimental and theoretical electron densities, allowing for accurate descriptions of Hal-, Chalc- and Pnic-bonding patterns, and of thermodynamic properties will be performed in Nancy.

The MOSAIC project “Multiscale Operando Structural chAracterization of vanadium phosphate Industrial Catalyst” is aiming at elucidating the evolution of the bulk of the vanadium phosphates during the catalytic process of the oxidation of butane into maleic anhydride. This class of material is exploited since the early 80 and a great number of studies have been dedicated to the optimization of the catalyst (new synthetic routes, introduction of promoters) according to empirical strategies. Although fundamental works have been mainly dedicated to the comprehension of the catalyst, they have mainly focused on the supposed active surface. But contrasted results on supported catalysts and very recent works correlating bulk properties and catalytic activity have evidenced the key role of the bulk material. Moreover oxygen diffusion in the material and relaxation of the vanadium by motion of atoms occurring during the catalytic process have been suggested but never thoroughly studied. We propose a multi-technique fundamental approach for unravelling in operando conditions the multi-scale structural properties of the whole catalytic materials. The combination of X-ray solid state NMR and diffraction/diffusion is the most promising way to approach local order in such materials and dynamic/oxygen diffusion. The results of this project may have an impact on the scientific community (design of new catalysts, methodological aspects for the characterization in operando, …). The proposed project is a new one and will rely on a consortium with remarkably complementary skills: Partner 1 – ISCR “Institut des Sciences Chimiques de Rennes ”, Teams “ Solid State Chemistry and Materials” and « Inorganic Theoretical Chemistry ” Coordination of the project. Elaboration of the materials. Ex and In-Situ laboratory as well as synchrotron X-ray diffraction/total scattering under controlled atmosphere and X-ray operando studies. Application of Maximum Entropy Method (MEM) and total scattering Pair Distribution Function (PDF) analysis to overcame the limitation of classical diffraction method. Solid state NMR studies and theoretical calculations of NMR parameters. Partner 2 – UCCS “Unité de catalyse et de Chimie du Solide” Lille Team NMR methodology and Glass materials : Development / improvement of sequences for Solid State NMR, Solid State NMR studies at very low field (51V) Partner 3 – LCS “Laboratoire de Catalyse et Spectrochimie”, Caen, In Situ and Operando Solid State NMR studies Solid state NMR developments (UCCS) will offer improved tool to characterize the local order in most of the catalytic phases. By combining the most recent evolutions in X-ray scattering (PDF, MEM) and solid state NMR experiments supported by theoretical calculations (CTI@ISCR) the static disorder, studied at room temperature will be deeply investigated and the kinetic effects (UCCS) during the elaboration of the different phases studied. In a second step, In Situ studies (variable temperature, static conditions) will be performed (ISCR, LCS) prior to operando studies (catalytic conditions) to evaluate structural changes during thermal treatments and possible apparition of dynamics (in the time scale of NMR spectroscopy). Finally the operando conditions will be applied (ISCR, LCS) and dedicated to the study of phase changes and dynamics within the materials leading to the discovery, of possible oxygen diffusion pathways related to the catalytic reactions. We will focus on different vanadium phosphate phases commonly found in the catalyst: paramagnetic compound ((VO)2P2O7 ) which is the major constituent and will not be studied so far by solid state NMR spectroscopy as it magnetic properties strongly affect the signal and diamagnetic compounds represented by different polymorphs of VOPO4. The most promising system is w- to d-VOPO4, very selective in catalysis but very disordered at room temperature.

The GOLD–RRAM research project aims at the investigation of a series of crystalline original gold dithiolene complexes, in a combined multidisciplinary effort between three groups, in Rennes (coordination chemistry, molecular conductors), Orsay (solid state physics, correlated conductors) and Nantes (material science, resistive switching), toward the use of such molecular conductors for information storage. These coordination complexes are formed upon the association of two 1,2-dithiolate ligands around a Au(III) metallic center, affording the corresponding monoanionic [Au(dithiolene)2]1– complex. The non-innocent character of the ligands allows for a reversible oxidation to the neutral radical complex [Au(dithiolene)2]• and their solid state association into stacks gives rise to paramagnetic conductors, devoid of any counter ions. Because of their radical nature, these original single-component molecular conductors behave as Mott insulators, with indeed one radical per site, at variance with most organic conductors with mixed-valence character. We have already shown on one original example (Rennes) that a transition to a metallic state is possible under application of external pressure (Orsay), suggesting that this structure is particularly sensitive to outer constraints such as chemical pressure effects or doping, or other stimuli such as electric pulses. The latter could favor a non-volatile resistive switching (Nantes), that is a transition between an initial high resistance insulating state ('0' state) and a low-resistance 'metallic' state ('1' state), one of the mechanisms investigated today for RRAM (Resistive Random Access Memory). These neutral radical complexes characterized with strong electronic correlations will be investigated here along two complementary routes, (i) the search for a stabilization of the metallic state in ambient conditions, particularly by chemical modifications of the dithiolene ligands (chemical pressure effects), by chemical doping of the neutral radical gold complexes with isosteric but closed-shell nickel analog or by surface doping within Field Effect Transitor (FET) devices, (ii) the investigation of a resistive switching effect, for further evaluation as potential candidates for RRAM devices, an attractive and fully unexplored possibility offered by their single-component, non-ionic but neutral nature.

The objective of this project is to develop multispectral molded optics operating simultaneously in the visible/short wave infrared (SWIR) and far infrared between 8-12 µm. These optics will allow the fusion of images taken in these two complementary spectral bands with the same optic, leading to a simplification of design and fabrication as well as important decrease of cost and weight. Imaging in visible/SWIR and in far infrared has many applications still in rapid growth. The fusion of the two complementary images will lead to many new applications both in commercial and defense fields. As an example, for car driving assistance, visible/SWIR image is better for reading road indications and for detecting the presence of ice on the road. Thermal image is much better for seeing further and pedestrians in foggy condition and during the night. For defense applications, it is, for example, easier to move in the dark with intensified SWIR image and thermal imaging is indispensible to detect hidden hot target. There are many optics operating either in the visible/SWIR region or in the far infrared region. Only two materials, known since long time, ZnS and ZnSe, can be considered for producing multispectral optics even they cover only partially these two spectral bands. These materials are fabricated with the long and expensive chemical vapor deposition (CVD). They are polycrystalline materials and consequently, no molded optic is possible. The only way to produce complex asphero-diffractive optics, indispensable with these materials, is to use the expensive single point diamond tuning. In this project, we propose to - develop some new glasses transparent from visible to far infrared up to 12 µm. - develop a molding process for fabricating multispectral optics - develop large band antireflection coating - study some potential applications with the multispectral optics. One commercial application and one defense application will be proposed. The originality and novelty of this project are associated with the following - Completely new glasses transparent from visible to far infrared will be developed. The base compositions are protected by a CNRS patent which has been extended to most industrialized countries. - The first molded multispectral optic will be developed - A system with fused visible/SWIR image and thermal image will be proposed with the same entrance optic, leading to simplified design and fabrication. This should be considered as breaking technological innovation. This consortium is composed of an academic laboratory and an industrial partner well recognized in their field of expertises, with a long term relationship of successful cooperations. These cooperations have, for example, allowed the industrialization of molded infrared optics which are installed in the BMW cars for driving assistance and also in the infrared cameras of the World most important manufacturer.