Structured mesoporous organosilicas from an acetonitrile-water template system

The synthesis of templated mesoporous silicas with a narrow pore size distribution can be achieved in a water/acetonitrile/n-dodecylamine system. The benefits of using this system compared to aqueous ethanol to prepare silicas are the much enhanced wall thickness, leading to greater structural stability, as well as a lack of co-surfactancy from acetonitrile, which means that the pore size remains constant over a wide range of solvent compositions. The particles obtained from this route are cylindrical, with partially aligned mesopores, in contrast to those obtained from aqueous ethanol, which are spherical and have a wormhole structure. A further major advantage is that the amine-functionalised materials, formed by direct co- condensation, are nucleophilic, in contrast to those prepared from aqueous ethanol. This latter feature allows for the elaboration of these amine functions to attach a range of more complex functionality, examples of which are given.