CORDIS - EU research results

Synthesis and characterization of porous molecular solids

Final Report Summary - POMOS (Synthesis and characterization of porous molecular solids)

The joint exchange programme aimed to establish and strengthen long-term cooperation in the field of molecular porous materials between the University of Salerno (Italy), the University of Stellenbosch (South Africa), the European Synchrotron Radiation Facility (ESRF, Grenoble, France) and the Institute Laue Langevin (ILL, Grenoble, France).
The joint research activity successfully explored the use of molecular compounds as building blocks for nanostructured porous materials by exploiting the specific expertise of each partner in the field of the synthesis and characterization of solid state materials.
Two types of molecular compounds were considered, namely calixarenes and cyclopeptoids, they represent very versatile compounds, which can be easily modified to achieve the desired building blocks.
The rules that control the solid state assembly of these macrocycles were defined and applied to the design and synthesis of new building blocks with desired solid state structure and properties.
The response of the materials to different gases or volatile organic compounds were tested by several ad-hoc techniques (pressure DSC, gas sorption microbalance). A specifically designed pressure cell for in-situ single crystal X-ray diffraction, developed at the University of Stellenbosch (South Africa), was used to characterize the compounds synthesized at the University of Salerno (Italy) allowing to define the host-guest interactions and understand the adsorption mechanism.
Synchrotron radiation provided by the European Synchrotron Radiation Facility (France) was used to detect structural modifications, when only very small single crystals or crystalline powders could be obtained. Unconventional experimental setups were provided by the Institut Laue Langevin (France).
Early stage researchers were involved actively in the project, allowing them to learn new techniques and alternative approaches in the experimental analysis.
The 1st Meeting on Porous Molecular Solids and the Satellite Meeting on Large Scale facilities, held in Stellenbosch on April 7-10 April 2015, brought together experts in the use of synchrotron radiation and neutrons in materials science and fostered an easier access to these facilities by South African scientific community. The successful outcome of the event promoted the organization of 2nd Meeting on Porous Molecular Solids to be hosted by the University of Salerno (Italy) in 2017.
The results of the exchange programme were published in peer-reviewed international journals and presented at international and national conferences, notably at the 28th European Crystallographic Meeting, Warwick (UK) in 2013, at the XXIII International Union of Crystallography Congress, Montreal (Canada) in 2014 and the 9th Peptoid Summit, Lawrence Berkeley National Laboratory, Berkeley (USA) in 2015.
In conclusion we discovered a whole new class of peptidomimetic compounds with very promising inclusion properties. In particular, we strategically designed a cyclic peptoid, which is able to change drastically, but reversibly, its conformation in the solid state upon guest release/uptake.
Thus, we were able to obtain the first molecular crystals, which reversibly open and close by sensing the presence of guest molecules without any loss of the crystal integrity.
The research activity allowed us to study how conformational flexibility in organic macrocycles may be exploited to lead to functional/porous materials, featuring both robustness and adaptivity. Moreover, these results suggest that easily tuneable cyclic peptoids may represent very promising building blocks, capable of reversible guest recognition and sequestration, at the frontier between materials science and biology.