Catalysis in Supramolecular Systems: the Case of Gel Phases

Supramolecular gels are a fascinating class of materials, originated by the self-assembly of low molecular weight molecules. Underpinned by non-covalent interactions, they find application in a diverse range of fields. Among these, supramolecular gels can be considered as organized, non-conventional reaction media, able to influence reactivity in a radically different way, compared with what happens in solution. This short review will focus on this aspect, covering literature from 2010 onwards, addressing the application of supramolecular gels as reaction media. In particular, in the first section we explore organocatalytic reactions in gel phase, with wide synthetic relevance, such as aldol and Mannich reactions as well as Friedel Crafts or ester hydrolysis processes. Subsequently, focus is laid on metal-catalysed reactions, among which relevance is given to widely used reactions like cross-coupling and click reactions. Then, the final sections describe the use of supramolecular gels as reaction media for photo- and biocatalysed processes.