Natural products and their biosynthetic routes are important sources of inspiration for chemists in their search for new environment-friendly and still highly efficient routes for the synthesis of fine chemicals. Carbon-carbon bond formation and cleavage are among the most difficult reactions. They usually require preliminary activation steps through the insertion of several, often transitory, functional groups. This frequently leads to an increase in the number of steps and a concomitant drop in the yields. Radical-based chemistry is a good alternative, thanks to its unique ability to activate otherwise unreactive positions such as aliphatic carbon atoms. The downside of this approach is that radical-based reactions are really difficult to control. In Nature, radical S-adenosyl-L-methionine (rSAM) enzymes are versatile radical catalysts capable of performing and tightly controlling over seventy different chemical reactions. With the CARBONARA project, we aim at determining the factors that control and drive radical-based C-C bond cleavage in rSAM enzymes. We want to address the key issues of substrate selectivity and activation, and the questions as to how these proteins control the radical-based chemistry to cleave one particular C-C bond over another and what tightly controls the termination of the reaction and the final products that are formed. To achieve these goals, we have selected five proteins with similar folds, readily available within the consortium, that catalyze C-C bond cleavage in amino acids. Our consortium consists of three internationally renowned partners with complementary expertise in the fields of biochemistry, structural biology and spectroscopy covering the fundamentals of this fascinating chemistry. Using X-ray crystallography, in vitro functional analyses, electron paramagnetic resonance spectroscopy and theoretical calculations, we want to characterize the functional, structural and electronic parameters that control the C-C cleavage reaction. In this way, we expect to understand and identify the key factors, which are intrinsic to the radical-based reaction itself and the extrinsic ones controlled by the protein matrix. Our original multidisciplinary approach should not only favor a more rational use of radical-based chemistry in organic synthesis, but also lay the foundations for the use of rSAM enzymes as new tools in synthetic biology, in particular through the development of rationally designed chimeras.

The wide goal of SPICS project is to provide enhanced electrode materials for supercapacitor application. SPICS aims at developing innovative 2D carbon layered materials with enhanced storage capability thanks to the use of redox active pillars. We aim to reach volumetric capacitance of about 400 F/cm3. The original idea of SPICS is to go beyond the use of simple mechanical pillars and to introduce redox functionality to enhance specific interactions with the electrolyte leading to improved charge storage capability. To achieve this goal, an important part of the project will be devoted to an in-depth analysis of the charge compensation mechanisms through the use and development of cutting-edge characterization techniques. Indeed, these fundamental investigations based on ss-NMR and DNP, SECM (Scanning Electrochemical Microscope) and QCM derived techniques (conventional EQCM, QCM coupled with EIS and QCM coupled to electroacoustic impedance) will be undertaken to understand the impact of these active pillars on the dynamics of ion transfer at the electrode/electrolyte interface, on kinetic rate transfer constants and on faradic reactions occurrences, and will also allow to evaluate the electromechanical and structural stress experienced by the material during cycling. For the electrochemical evaluations, different electrolytes will be tested (from ammoniums salt in CH3CN to ionic liquids-based electrolytes). This tight relation between material development, advanced characterization and electrochemical evaluation will lead to the establishment of a virtuous circle resulting in a major breakthrough in correlating electroadsorption/charge transfer phenomena to smart 2D carbon materials properties, enabling the design of refined material and the selection of the most promising ones. The best material will also be tested with a solid-state electrolyte based on the use of ionogel. Supercapacitors with performances at the state of the art are expected to be achieved with these innovative 2D smart carbon materials, capacitances as high as 300 F/g and 400 F/cm3 with 90% charge retention over 10 000 cycles. Hence SPICS bridges fundamental mechanisms understandings efforts to preliminary tests responding to an important societal demand. The development and optimization of these next generation active pillared graphene materials will be enabled a close partnership between CEA, CIRIMAT and LISE. The expertise and complementarity of the 3 partners - in graphene–based materials developments, ss-NMR analysis of modified samples, electrochemical material characterization, advanced and SECM techniques - are fundamental to the success of the project. Indeed, the skills and know-how of each partners are highly relevant and necessary to address the project WPs inter-connexion, to allow an efficient project progression, to finally achieve the objectives stated above.

The photophysical properties of trivalent lanthanides make their complexes particularly suitable for the development of fluorescent probes for biomedical applications and for the design of optical devices (sensors, light emitting diodes, solar cells, lighting). To date there is a strong interest to shift the emission of the probes or devices components in the low energies and use the near infrared area to increase their performance. The development of efficient architectures for the sensitization of the luminescence of lanthanide ions emitting in the near-IR range, remains an important challenge and performance of the existing systems could be significantly improved by a better design of the molecules employed to chelate lanthanide ions. Progress in optical devices in the NIR depends on the development of the excitation in the visible with combining high stability of the systems, high sensitisation, and high quantum yields. A nanometer scale approach is particularly attractive by the fact that an important number of lanthanide ions and can be implemented in a small volume with all the implications in terms of intrinsic properties. Then emissive nanoparticles will be particularly attractive for biological imaging due to the high emission and intensity per unit of volume of these luminescent tags. The project is based on a multidisciplinary approach to design original lanthanide- and nanocrystal-based nanosized system and organized into three main axes: i) Determination of the fundamental coordination properties which lead to a deep understanding and to the optimisation of the sensitisation of NIR lanthanide emission and optimisation of the coordination properties. ii) Sensitization of the luminescence of NIR-emitting lanthanide ions by semiconductor nanocrystals and investigation of the energy transfer processes involved. This project will involve the optimisation of the energy transfer pathways within the systems by controlling the grafting of the luminescent lanthanide chelates on the nanocrystals and then their respective distance. iii) The evaluation and studies of the potentialities of the developed Ln-based optical devices for application in cellular and small animal in-vivo NIR imaging. Moreover, other fields such as for anti-forgery fluorescent labels, light-emitting diodes and solar cells will be explored in parallel in collaboration with local and regional, partners. We will use the technical platforms of the institutes and the lighting and energy research facilities of CEA Grenoble for material applications and the solar energy performance measurement line of the INES The results we expect are as follows: i) First realisation of near infrared emitting quantum dot sensitized-lanthanide optical device presenting high luminescence quantum yields by achieving efficient excitation in the visible; ii) Establishment of a better understanding of the ligand-lanthanide and nanocrystals-lanthanide energy transfer processes; iii) “In vivo” evaluation of the applicability of these probes as fluorescent tags and determination of their biodistribution by luminescence imaging. The fundamental knowledge obtained in this project will have important implications for the development of new optical probes and devices with convincing demonstrators.

Structures that strongly confine the photons on the scale of the light wavelength have been studied in semiconductor physics for about 20 years, giving rise to a wealth of fundamental studies exploiting the reinforced light-matter (both linear and nonlinear) interaction. Most studies were done in well mastered III-V material systems, which however suffer from some drawbacks such as a low exciton binding energy, low barrier potentials in heterostructures and a transparency window limited to the near infrared. Semiconductors of the III-N family have quite peculiar properties such as a large excitonic binding energy and a transparency window that extends to 200 nm. They are the dominant material family for the fabrication of UV-blue-green optoelectronic devices (laser diodes and light-emitting diodes) as well as for white light production. Nitrides are already massively used for high density optical storage and display light sources but shorter wavelength optoelectronic devices are also potentially very interesting for biochemical sensors, purification, disinfection and medical diagnosis. Interestingly, a current trend consists in integrating III-N materials on silicon. For these reasons, III-N materials are thus expected to play a significant role in novel photonic systems and, in this respect they are very good candidates to probe light-matter interaction in photon confining structures. It is however notorious that III-N semiconductors are difficult to process and this technological drawback has hindered achievements in highly confined optical structures. It is the aim of the QUANONIC project to probe quantum optical and nonlinear effects in AlGaN based high optical quality microdisks and photonic crystal (PC) structures. Based on the know-how of the consortium to fabricate and to probe III-N based microcavities, several goals will be pursued and if successful will represent major breakthroughs for the development of novel optoelectronic devices integrated on silicon. Goal 1 : Microlaser and strong coupling at UV wavelengths in III-N microcavities. Fabrication of optical resonators having high quality factors is now mastered by the consortium. The next issue to address to reach lasing is the optimization of the active region in order to get high gain active medium: our strategy is twofold. i) We will seek to grow GaN/AlN quantum dots (QD) with high oscillator strength and high areal density. A detailed study of microlasing and Purcell effect will be made. ii) By exploiting the large oscillator strength of III-N excitons, high quality factor microcavities will be designed for photon-exciton strong coupling. We shall explore the conditions for strong coupling, both for confined modes and for extended modes in III-N photonic crystals. The ultimate goal will be to reach polariton lasing. Goal 2 : Frequency conversion in III-N photon confining structures for deep UV sources. Thanks to a much wider transparency window than conventional semiconductors and to large nonlinear coefficients, III-N are very good candidates for frequency conversion in confined structures. The photonic crystal geometry allows for large field intensities (cavity enhanced frequency conversion) and also for the tailoring of the refractive properties. Original phase-matching conditions will be demonstrated experimentally, such as backward second harmonic generation (SHG) and “all angle” SHG that are very difficult or impossible to obtain in larger scale periodically poled nonlinear materials. As a final and ambitious objective of the project, we propose an investigation of a compact coupling of semiconductor lasers and frequency converting cavities that enlightens the potentialities of our approach for forthcoming UV optoelectronics. The integration of nitride laser emission and frequency doubling in a III-N photonic structure represents a realistic opportunity to demonstrate an all-semiconductor compact optical source operating in the 200-250 nm wavelength range.

Structural phase transitions are ubiquitous in everyday's life and have given rise to various applications in information technologies and energy storage for instance. They exploit functional materials, whose properties change significantly upon a structural change, induced by a control parameter. These materials have so far been considered in a bulk form or as thin films. Works on structural phase transitions in two dimensions (2D), initiated in the 1970's, have focused on lattices of atoms or molecules in weak interaction, which are little suited to the design of functional materials of relevance for applications. Two-dimensional crystals, which are more cohesive, offer new opportunities in this respect, first in reason of their unique properties differing from those of thicker materials, second in reason of their reduced dimensionality. We expect the latter to ease the structural phase transitions, a desirable characteristics in view of faster and less energy-costly applications. In our project, we will explore compounds whose potential for structural phase transitions and applications based on them has only be skimmed over. These compounds, unlike carbon which is little prone to transform once in the graphene phase, exhibit considerable polymorphism in the bulk. They are the 2D transition metal dichalcogenides and crystalline silica, which were recently reported to experience structural phase transitions but without clear evidence of control. Based on our recent unpublished results, we plan to achieve a full understanding at the thermodynamics and kinetics level, down to elementary processes, of the phase transition in 2D, to demonstrate changes of properties (electronic, vibrational, optical, reactivity) occurring due to the phase transition, and to build advanced architecture combining two 2D crystals. Our work will exploit surface science approaches coupled with state-of-the-­art atomistic simulations to develop advanced materials on demand, to achieve proof-of-concepts and to allow insightful understanding of the underlying mechanisms. Our work will also address phase transitions beyond the stringent conditions typical of surface science experiments, with the ambition to broaden the potential of phase change materials based on 2D crystals. Potential applications of such materials could include flexible rewritable memories, reconfigurable photonic devices, and controllable catalytic systems. The project will involve three partners with complementary expertise, Institut Néel (Grenoble), Institut Nanosciences et Cryogénie (Grenoble), and Institut Jean Lamour (Nancy).