Solubility and Aggregation Behavior of Dendronized Poly(p‐Benzamide)s

Abstract

A series of Fréchet dendronized poly(p-benzamide)s have been synthesized. To attach the dendron-functionalities to the poly(p-benzamide) backbone, a propargyl side chain was introduced to p-aminobenzoic acid. Then, copper catalyzed azide-alkyne cycloaddition was used to click a first generation (G(1)), respectively, a second generation (G(2)) Fréchet-dendron azide onto the amino acid monomer. The resulting amino acids were polymerized using triphenylphosphite to obtain a poorly organo-soluble G(1)-dendronized polymer and a non-aggregating G(2)-dendronized polymer showing good organo-solubility. Furthermore, a strictly alternating non-aggregating G(1)-TEG-dendronized polymer with good organo-solubility was synthesized. The aggregation behavior of these polymers was investigated by dynamic light scattering.

Synthesis of well‐defined, soluble poly(3‐alkyl‐4‐benzamide) by chain‐growth condensation polymerization

“…9,10 Another approach to improve the solubility is the attachment of flexible side chains to the aramide backbone. [13][14][15][16] In recent years, Kilbinger introduced dendrons 17 and a hexyloxy side chain at the 2 position of poly(4-benzamide), and tri(ethylene glycol) monomethyl ether (TEG) side chains at the 2 18,19 and both the 2 and 5 positions. 19 The solubility of these polyamides is sensitive to side chain structure.…”

Controlling Molecular Self-Assembly on an Insulating Surface by Rationally Designing an Efficient Anchor Functionality That Maintains Structural Flexibility

“…Here, we present a linking strategy based on the development of a versatile molecule from the class of shape-persistent oligo( p -benzamide)s that provides stable and site-specific anchoring of the molecular building block toward the surface of a bulk insulator, namely, calcite(10.4). Due to their inherently extended chain structure and their ability to form hydrogen bonds between chains, − shape-persistent oligo( p -benzamide)s are promising candidates for use as supramolecular building blocks and the creation of molecular rods . The building block is specially designed to allow for electrostatic interaction of iodine atoms with the surface calcium ions, thus ensuring a strong and site-specific anchoring.…”

Non-aggregating Poly(p-benzamide)s

“…To suppress aggregation via stacking interactions, Fréchet dendrons [3] of first (G1) and second (G2) generation were attached to the aromatic backbone using p-aminosalicylic acid derivatives (Fig. 2), [4] following up on a very successful strategy previously exploited by the Schlüter group. [5] Indeed, G2 Fréchet dendrons are bulky and flexible enough to prevent π-interactions while maintaining good solubility.…”

“…On the basis of our latest achievements in the field of substituted oligo-and poly(p-benzamide)s we gained access to non-aggregating, shape-persistent rods for the construction of nanoscopic objects. Combining sequence control through automated peptide synthesis [6] with the rigidifying, solubilitymediating behavior of Fréchet dendrons and triethylene glycol side chains [4] we are now able to build linear arrays in which functionalities can be placed at specific distances from each other. In addition, the use of different side groups (sterically demanding, hydrophilic, lipophilic) will provide us with shape persistent scaffolds in which amphiphilicity patterns can be designed to create exciting new self-assembling structures.…”