Porphyrin-naphthodiimide interactions as a structural motif in foldamers and supramolecular assemblies

pi-pi Stacking interactions between electron deficient naphthalenediimides (NDI) and electron-rich porphyrins (POR) leading to charge transfer are shown to be prevalent in linked NDI-POR and POR-NDI-POR structures. For flexibly-linked systems, intramolecular interactions lead to S-shaped foldamers in solution, whereas intermolecular association is predominant in more rigid systems. The foldamer structures can be interrupted by competing aromatic solvents, by six-coordination of metallated porphyrin derivatives, by protonation of the free base porphyrin in non-metallated structures, and in facially sterically hindered porphyrins.