Influence of Ester versus Amide Linkers on the Supramolecular Polymerization Mechanisms of Planar BODIPY Dyes

We report the H‐type supramolecular polymerization of two new hydrophobic BODIPY derivatives equipped with ester and amide linkages. Whereas the ester‐containing BODIPY derivative undergoes an isodesmic supramolecular polymerization in which the monomers are parallel‐oriented, the replacement of the ester by amide groups leads to a highly cooperative self‐assembly process into H‐type aggregates with a rotational displacement of the dye molecules within the stack. The dye organization imposed by simultaneous π–π and hydrogen bonding interactions is the driving force for the cooperative supramolecular polymerization, whereas the absence of additional hydrogen bonds for the ester‐containing moiety does not suffice to induce cooperative phenomena. Small strokes make big change: Two new hydrophobic BODIPY dyes, which only differ in the linking group (ester vs. amide; see figure), were synthesized and fully characterized. Exchanging the ester linkages with amide groups is found to influence the mode of self‐ aggregation by tuning the isodesmic supramolecular polymerization to a cooperative process.