Structure-activity relationships of simple molecules adsorbed on MOF materials: in situ experiments vs. theory

Metallorganic Frameworks (MOFs, also known as “Coordination Polymers”) are crystalline nanoporous materials comprised of metal containing clusters connected three-dimensionally by poly-functional organic ligands. The ligands act as spacers, creating an open porous three-dimensional structure, with very high pore volume and surface area.1,2 This hybrid architecture opens the possibility to design and synthesize a great variety of new porous materials, which are in principle able to display novel functionalities that are potentially exploitable for a number of applications in catalysis, ion-exchange, non linear optics, as sensors, in gas separation and/or storage.3-5 The key step for most of the foreseen applications is the solvent removal treatment, that allows make accessible the large pore volume to the desired molecules. For several cases (among all MOF-5, HKUST-1, CPO-27-Ni, UiO-66), the combined use of XRD, EXAFS, XANES, UV-Vis, IR and Raman techniques, supported by ab initio calculations, allowed us to obtain a complete understanding of the structural, electronic and vibrational properties of MOF materials. The adoption of in situ experimental set-ups guarantees the possibility to follow the evolution of such properties along the solvent removal process and the successive interaction with increasing amount of desired adsorbate (H2, N2, CO, NO, CO2, etc…).6-2