Modulating the Differentiation of Kinetically Controlled Supramolecular Polymerizations through the Alkyl Bridge Length

Abstract

The synthesis and self-assembling features of N-annulated perylenebisimides (N-PBIs) 2-4 are reported and compared with the complex self-assembly of N-PBI 1. The studies presented herein demonstrate that increasing the length of the alkyl spacer separating the central aromatic core of the dye and the peripheral side chains cancels the differentiation on the corresponding supramolecular polymerization. Thus, only 2 is able to form two different supramolecular polymorphs. The formation of kinetically trapped monomeric species is observed for all the N-PBIs 2-4. These metastable species, constituted by intramolecularly H-bonded pseudocycles of 7, 8, 9, or 10 members for compounds 1, 2, 3, and 4, respectively, provoke kinetically controlled supramolecular polymerizations that can be accelerated by the addition of seeds. The results presented herein shed light on the intricate process of differentiation in self-assembly.

Effect of chirality in the supramolecular polymerization of N‐annulated perylenediimides: Cancelling pathway complexity

“…In this good solvent, the stretching NH band appears at higher wavenumber (3410 cm −1 ) that is ascribable to intermolecular H‐bonding interaction (Figure 2B). 16,29,30 The formation of the metastable monomeric species has been also detected by VT‐ 1 H NMR and 2D‐ROESY experiments in CDCl 3 at diluted conditions. Thus, the 1 H NMR spectra of (R)‐ 1 at different temperatures show that, unlike the concentration dependent 1 H NMR spectra shown in Figure 2A, no shifts are observed for the aromatic resonances.…”

“…This FTIR spectrum shows the stretching bands for the NH group at 3310 cm −1 and at 1644 cm −1 for the amide, values that has been ascribed to intermolecular H‐bonds between the amide groups in referable systems (Figure 2B). 16,30,31 …”