MOFSCO

Metal-Organic Frameworks (MOFs) are ideal materials for the modular design of complex assemblies, as they possess a long-range ordered hybrid structure associated with well-organized micro- or mesoporous channels and/or cages. Their chemical composition (metal cation, ligand) can be easily tuned, through direct or post-synthetic methods, as well as the presence of Lewis, redox, photoactive or acid/base Brönsted centers within the framework. This large chemical versatility combined with the huge structural diversity, offers a unique opportunity to generate a diversity of structures and compositions, making them of great interest for various applications such as gas storage, separation, catalysis, drug delivery, etc. Several MOFs can be used for sensing small molecules, mainly through the modulation of their emissive properties. However, the limited stability of these systems prevents them for being used in real devices. Taking into account the ability of porous MOFs to encapsulate various types of guest molecules, like metal-coordination complexes, into their porosity, through bottle in a ship inclusion or post-synthetic encapsulation, this project aims at a novel route to develop sensing materials, i.e. the inclusion of spin crossover complexes (SCO) inside the pores of MOFs. Indeed, SCO complexes are capable of switching their spin states upon external stimuli such as temperature. This switching phenomenon is accompanied by change in many physical properties such as color, magnetic susceptibility, thermal/electric conductivity, dielectric constant etc. making them promising candidates for technological applications such as molecular switches and sensors. The encapsulation of such complexes in the pores of MOFs remains almost unexplored to date while one can expect not only the SCO complexes properties to be exploited and even enhanced by confinement effects but also to be modulated through the selective sorption of guests in the MOFs, which would lead to enhanced sensing properties. In this context, our objective is to develop an entirely new area of MOF-based-sensors by fabricating MOF-SCO composites. This will be done by incorporating some designed SCO complexes in the pores of robust MOFs, shaping them to nanoparticles/thin films and use the composites in sensing applications.