Porous molecular solids offer an attractive alternative to nano-structured materials. These organic compounds can be tailored in terms of pore size and functional groups lining the pores for very high selectivity. Further, dynamic molecular structural changes can also be exploited. The EU-funded project POMOS (Synthesis and characterization of porous molecular solids) focused on calixarenes and cyclopeptoids that form cavities capable of holding small molecules or ions, creating a host-guest system. Both these macrocyclic organic compounds can serve as building blocks of devices relying on gas-solid interactions. Calixarenes had already been successfully employed as building blocks of nano-structured materials, but cyclopeptoids were relatively unexplored. Against this backdrop, researchers synthesised and characterised new calixarene- and cyclopeptoid-based compounds using single-crystal and powder X-ray diffraction. They tested the calixarene-based compounds for gas adsorption properties under non-ambient conditions using a pressurised gas cell. The experimental set-up allowed researchers to examine host-guest interactions at atomic level in order to better understand adsorption mechanisms. Data were obtained at major European facilities through synchrotron radiation and neutron diffraction. Specifically, high-intensity monochromatic radiation available at the European Synchrotron Radiation Facility (ESRF) allowed scientists to perform in situ single-crystal and powder X-ray diffraction. POMOS methodologies for fabrication and characterisation of porous molecular materials will be instrumental in the development of new devices for capture, separation and storage of gases. Such devices are of tremendous commercial interest in an important global market.
Porous materials, gas capture, POMOS, calixarenes, cyclopeptoids