Coordination-driven assemblies based on meso-substituted porphyrins: metal-organic cages and a new type of meso-metallaporphyrin macrocycles

Abstract

Coordination-driven self-assembly of (metallo) porphyrins can produce complex metal-organic architec-turesbringingnewfunctionsandapplicationsin,forexample,molecularrecognition,sensing,andcatalysis.With the aim of constructing multiporphyrinic functional systems, this review provides an overview of therecent advances in the field of discrete metal–ligand assemblies based onmeso-substituted (metallo)por-phyrins with a particular focus on describing the functions that emerge from self-assembly as well as fram-ing perspectives for future areas of research. The discussion is restricted to two supramolecular researchdomains related to (metallo)porphyrins whosemeso-positions are directly involved in the self-organization process. First, we describe notable examples of (metallo)porphyrins functionalized with coor-dinating groups, which have served as building blocks to create discrete porous ‘‘Coordination Cages” withapplications in guest-binding and as platforms to mediate chemical reactions. Secondly, we present theprogress in the synthesis of ‘‘meso-metallaporphyrins”, a new type of porphyrin-like macrocycle that ischaracterizedbythepresenceofmetalionsatthemeso-positionsoftheframeinsubstitutionofthemethine@CHAbridges; likewise,the traditional pyrrole units are replaced by triazole rings to afford coordination tometals. We thus aim to provide new methodological insights into the design of coordination porphyrinicassemblies towards the enhancement of their properties and the building of new functions.