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. [ABSTRACT FROM AUTHOR]