Multi-Length Scale Communication Effects in Catalysis: Thinking Big and Acting Small

The use of hierarchically structured materialsas catalysts has been finding increasing applicationin the past years. For these catalytic systems, notonly the nano-scale matters: a high degree of orderacross multiple length scales, along with its controland analytical assessment, is of paramount importanceto obtain innovative properties that can findapplication in catalysis. Most reviews dealing withhierarchically structured materials are concerned withthe “bottom-up” transfer of structural informationalong the different length scales, with specialemphasis on the transmission of chirality. Due to theirmesoscale size together with their complex behaviour,these systems are often susceptible to feel theeffects of macroscopic forces, that can exert a “topdown”control of their catalytic properties, so that anexternal stimulus, acting at the level of thesupramolecular architecture of the catalyst, canultimately determine the outcome of the catalyzedreaction at the molecular level. We review in thispaper some recent reports that deal with the experimentalimplementation of this concept, either byusing a mechanical force in a full range directtransmission to the reaction coordinate, or by meansof a stepwise relay transmission from the macroscopiclevel (purely supramolecular chirality) to thenanoscopic one. We focus in this review on thesemulti-length scale communication control effects,identifying the different mechanisms that are affectingthe catalytic activity.