Pillar[5]arene-porphyrin conjugates: from molecular flowers to photoactive rotaxanes

Abstract

Our groups are involved in a research program on the development of molecular and supramolecular systems combining pillar[5]arene building blocks with porphyrins. Functionalization of both rims of the pillar[5]arene scaffold with metalloporphyrins generated giant molecular machines mimicking the blooming of a flower as well as light-harvesting devices. On the other hand, we have also used the host-guest properties of pillar[5]arene derivatives to prepare photoactive mechanically interlocked molecules. In such compounds, complementary subunits are associated into a single molecular ensemble but without being connected through covalent bonds. Inter-component photo-induced energy transfer processes remain however extremely fast in these systems despite the exclusive link through mechanical bonds. All these results are described in the present review.