The SWITCH project is a European doctoral network that is currently being built to support the transition from the known synthesis of switchable molecules to their implementation into operative devices. For that purpose, a consortium of experts in spin crossover systems (chemistry, properties and modelization) has started to be built and needs to be reinforced to cover as much as possible the main current challenges of molecular materials sciences for chemosensors, molecule-based electronics and barocaloric refrigeration. The scientific complementarity of the partners will be an asset for both the success of the various challenges tackled as well as for the high-level training of the doctoral candidates hired in the frame of this project. Indeed, up to fifteen doctoral candidates are planned in chemistry, physics and theoretical laboratories. Various actions will be planned to level-up their skills and create a network of young researchers for future collaborations. The MRSEI action will help building this doctoral network project by funding travels and a graphic designer to improve the quality of the project presentation.

Refrigeration systems used in our daily lives (air conditioners, refrigerators...) consumed up to 20% of the global electricity production in 2019 and are responsible for 8% of global greenhouse gas emissions. Alternatives are therefore actively sought, in particular through the compression of solids (mechanocaloric effect). This requires materials with significant structural changes, such as in spin conversion phenomenon which is accompanied by large volume changes under pressure. In this context, the BRef project aims at elaborating densified spin crossover pellets using sintering technic to study their thermal conductivity and cooling efficiency for further integration into barocaloric refrigeration devices. The project lies on the unique convergence of expertise of the Switchable Molecules and Materials team of the ICMCB on the elaboration of such densified materials and their characterization under pressure.

Cultural heritage, as represented by collections in museums and the built environment, is a unique resource in socio-cultural and economic terms. Climate change will lead to extreme events such as droughts and floods, severe storms and heat waves occurring more frequently across Europe. While the impact of climate change on society and ecosystems has garnered significant attention, the consequences for cultural heritage have largely been overlooked. The major factor controlling the impact of climate change on heritage buildings hosting collections, surrounded by natural environments is water (in excess or in stress) and its transfer. In this context the project aims to understand the role of the water cycle on cultural heritage site conservation with an holistic approach considering water dynamics at three scales : - The liquid water in the natural environment (soil and vegetation in gardens and parks) - The liquid to vapor water transfer within the architectural building envelope (monument) - The vapor to liquid water in interiors and collections (condensation phenomena) This research explores how heritage sites can be resources for climate mitigation, adaptation and sustainable development through optimal management of the water cycle in and around them. Our objective is to identify levers at the heritage site scale to optimise conservation of cultural heritage while improving water management and reducing energy consumption. To achieve the project objective, a transdisciplinary approach will combine historical, experimental, theoretical and numerical studies of water transfers across three scales at real heritage sites with respect to climate data. Building on the resultant improved understanding of water transport, passive solutions as well as innovative materials and techniques will be integrated and optimized. Using these levers, the project will establish how the nature-culture relationship (soil-vegetation-buildings-museum collections) could be the key to making European cultural heritage more resilient.

Development of efficient, eco- and environment friendly substrates for the oxidation of H2, a green energy carrier, is required to substitute rare and expensive noble metals. Frustrated Lewis Pairs (FLP) allow the heterolysis splitting of H2 but no electron is released from H2. Inspired by [FeFe]-hydrogenases in nature, organometallic models are developed, but very few are able to oxidise H2. Aiming H2 oxidation, this project propose to study the intermolecular or intramolecular FLP formed by a borane-based Lewis acid associated to a cooperative bimetallic assembly Fe(I)Fe(I) acting as a Lewis base, able to transfer both electrons and protons. Novel FLP combining a [FeFe] bimetallic complex and a borane will be characterized by spectroscopic and electrochemical methods, reactivity with H2 will then be studied.

Aiming at enhancing the work-hardening behavior of strategic light-weight and corrosion resistant Ti-alloys, the TWIP (twinning induced plasticity) Ti-alloys family was developed. Playing with the stability of the ?-phase (body centered cubic), the TWIP mechanism can be triggered. Thanks to this alternative deformation mechanism, complementing dislocation glide, a large work-hardening rate could be obtained in alloys of the ?-metastable family, as simple as single-phase binary Ti-15Mo alloy. However, TWIP Ti-alloys display a rather low yield strength. To further optimize the mechanical properties without sacrificing the concept of working on simple systems, the opportunity of microstructure optimization, and in particular tuning the structure and chemistry of the grain boundary, will be investigated. Indeed, grain boundaries are in continuous interaction with the dynamically formed mechanical twins, from their nucleation to a possible twin transmission to a neighboring grain. Although this parameter seems critical to understand and ultimately control the alloy deformation, studies considering the grain boundaries of TWIP Ti-alloys are scarce, and only focus on the mechanism of twin transmission without considering other parameters, such as a possible segregation at the grain boundary. By comparing the Ti-15Mo, Ti-15Mo-xO and Ti-15Mo-1.5Sn alloys, the influence of the grain boundary character (low- or high-angle, at- or out-of-equilibrium following forging-like processes) and its chemistry (from elemental segregation of oxygen or Sn to phase precipitation) on the mechanical twinning (nucleation and transmission) will be assessed. Based on the results, strategies aiming at emphasizing some mechanical properties, such as the yield strength, through grain boundary engineering will be proposed and implemented in a proof of concept.