Imidazolium Based Cross-Linked Nanostructures from POSS molecular bricks for the Efficient Conversion of Carbon Dioxide

Abstract

Polyhedral oligomeric silsesquioxanes (POSS) have been employed as molecular bricks for the synthesis of imidazolium cross-linked networks as heterogeneous catalyst for the conversion of carbon dioxide into cyclic carbonates via reaction with epoxides. Two hybrid materials with different nucleophilic species (bromide and iodide) have been prepared and characterized by means of elemental analysis, 13C and 29Si solid state NMR, thermogravimetric analysis and IR spectroscopy. The solids were tested as the sole catalyst under metal- and solvent-free reaction conditions showing full selectivity toward the formation of cyclic carbonates and outstanding productivity values. Several epoxides were reacted with CO2 proving a good catalytic versatility. The recyclability of the materials was successfully verified for four consecutive runs allowing to consider them as promising candidates for continuous flow technologies.