1. Preparation of new robust and crystalline MOFs using oxamidato- and oxamato-based ligands derived from biomolecules and robust aromatic amines derivatives of chiral amino acids as ligands. These MOFs show tuneable pore size and functionality, as a direct consequence of the size and chemical nature of the chosen amino acid residues, which must be capable to anchor to the pores the desired metallic species in subsequent Tasks. These materials have been also explored with excellent results in other fields such as water environmental remediation. In this context, we have reported a new MOF derived from the amino acid L-serine that can be used in the molecular recognition and sorbent extraction of hydrophilic vitamins in juices. Another MOF has been also used for the efficient capture and separation of greenhouse gases and neonicotinoid insecticides, organic dyes, antibiotics and recreational drugs. We have also developed a family of multivariate MOFs (which are being used for the in-situ preparation of heterometallic SNMCs) that shows excellent properties in the capture of organic and inorganic contaminants and also in enzymatic catalysis, mimicking the active centers of enzimes. Finally, some of these MOFs are being processed as mixed matrix membranes (MMM-MOFs) and/or FOAM-MOFs and explored their application in different technological applications.
2. We have carried out the MOF-driven preparation of different SNMCs and single atom catalysts (SACs) using the MOFs described in the previous section. In so doing, we have achieved the formation of different well-defined ligand-free Ag2 and Au3 SNMCs and Pt and Pd SACs. In addition, such small species have been characterised by using SC-XRD, being the first examples of SNMCs and SACs characterised crystallographically within MOFs. As planned, we have explored their catalytic activity which is outstanding in some cases. For example, Pd SACs have shown excellent activity and reusability in the selective oxidation of primary alcohols to carboxylic acids. Other SNMCs are showing also excellent results in industrially relevant reactions like the water gas-shift reaction or the selective hydrogenation of olefins and paraffins.
3. The sequential step-by-step synthesis of homometallic (Task 2) and heterometallic (Task 3) SNMCs has been also carried out. We have synthesised unprecedented examples of SNMCs of growing nuclearity (Task 2) and heterometallic SNMCs (Task 3). These species show and outstanding catalytic behaviours in different reactions of industrial interest. For example, the AgFe species showed a unique catalytic activity for the direct conversion of styrene to phenylacetylene in one-pot. Moreover, AuPd nanoclusters exhibited outstanding activity in the semihydrogenation reaction of acetylene in ethylene, surpassing the state of the art catalysts.
4. The last point related to the objectives of the project has consisted of the multigram–scale manufacture of SNMCs and industry scalability. For that, we have taken advantage of the results obtained in previous Tasks. A large plethora of interesting materials have been prepared and tested in catalysis. The next step consisted on scaling-up their preparation. For that synthetic pathways were optimised (also aiming at making them economically viable). In so doing, direct large syntheses (more than 100 g) have been carried out in only one step, which indeed constituted a challenge for MOFs syntheses.
In general, all the results obtained here have been disseminated through the most common means in Science, such as publications, participation in scientific conferences through invited lectures, and the development of patents (www.mupomat.com). In addition, a significant portion of the results obtained in this project form one of the fundamental pillars for the near future of the MUPOMAT group. In this regard, the group has taken initial steps toward establishing a spin-off focused on the industrial application of MOFs.
