Periodic Reporting for period 3 - S-CAGE (Smart Coordination Polymers with Compartmentalized Pockets for Adaptive Guest Entrance) Reporting period: 2020-05-01 to 2021-10-31 Summary of the context and overall objectives of the project The S-CAGE project aims to develop a new generation of crystalline solids with periodically-organized discrete voids, or compartments, that would benefit from the combination of the high stability and robustness of dense materials with the structural diversity and versatility (and therefore large applicability) of open frameworks. These coordination polymers (CPs) will be capable of interacting with guest species due to the presence of dynamic entrances. This could open new horizons towards the design of unprecedented materials as an enhanced interplay between the guests and the frameworks will be achieved.The main objectives of S-CAGE are:i) Chemical design of compartmentalized 1D, 2D and 3D coordination polymers. These materials will be designed in such a way that they will provide ideal room to accommodate different guest molecules, which can be easily tuned depending on the target guest.ii) Advanced structural characterization, including modern diffraction studies under pressure of gas and volatile guests. This strategy will provide unequivocal prove of the location of the guest molecules in the internal voids and gain insights of the mechanism of entrance. The direct visualization of the modes of interactions of different gases will permit a deep comprehension of the nature of their interaction.iii) Gas separation studies. This involves the development of materials that could specially serve for gas separation and improve the performances of zeolites and current MOFs.iv) Sensing capabilities through changes in magnetic properties. The chemical design followed in S-CAGE will result in magnetic CPs with confined spaces which should enhance the interaction of the guest molecules with the framework, and thus a change in their magnetism is expected Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far The project is advancing with very positive results, which have resulted so far in 13 publications in high-impact journals: 1 Nature Chemistry (which has been selected as “cover of the year”), 2 Journal of the American Chemical Society, 1 Chemical Society Reviews, 2 Chemical Science (1 of them selected as front cover), 2 Chemistry European Journal, 1 Dalton Transactions, 1 Chemical Communications, 1 CrystEngComm, 1 Chemical Engineering Journal and 1 Beilstein Journal of Nanotechnology. In addition, we have contributed to the dissemination of the results of the project with around 50 contributions to conferences. Furthermore, our work has appeared in several outreach media such as Chemistry World and The Huffington Post, and the PI has been interviewed in several radio programmes (three different national channels) and 1 TV interview.The major achievements that have been obtained are:1. The study of the selective sorption and magnetic response of a compartmentalized coordination polymer presenting spin-crossover phenomena (published in Chem. Sci.)2. The formation of a flexible MOF presenting mesopores, micropores and discrete cavities (published in Chem. Sci. and JACS).3. The formation of a 2D magnetic material that can be exfoliated and be used as a sensor (published in Nature Chemistry)4. The development of a new methodology for the preparation of Fe(II) MOFs (published in JACS)Nevertheless, other important results have been already published, and some other preliminary results are currently being under investigation and we expect to publish soon. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) The results of the project are clearly beyond the state of the art, as evidenced by the high quality of the journals in which the results have been published, including one publication in Nature Chemistry. Preliminary results, yet to be published, indicate that this high-level of the results will continue in the near future. More specifically, the separation capacity of the materials developed so far indicate very promising capacities in this field. In addition, the high versatility of coordination chemistry will allow us to modify the physical properties of the hierarchical MOFs and 2D materials already developed.