Relationship between Side‐Chain Polarity and the Self‐Assembly Characteristics of Perylene Diimide Derivatives in Aqueous Solution

Abstract

Perylene‐3,4,9,10‐tetracarboxylic acid diimides (PDIs) have recently gained considerable interest for water‐based biosensing applications. PDIs have been studied intensively in the bulk state, but their physical properties in aqueous solution in interplay with side‐chain polarity are, however, poorly understood. Therefore, three perylene diimide based derivatives were synthesized to study the relationship between side‐chain polarity and their self‐assembly characteristics in water. The polarity of the side chains was found to dictate the size and morphology of the formed aggregates. Side‐chain polarity rendered the self‐assembly and photophysical properties of the PDIs—both important for imminent water‐based applications—and these were revealed to be especially responsive to changes in solvent composition.

Synthesis and Self‐Assembly of Bay‐Substituted Perylene Diimide Gemini‐Type Surfactants as Off‐On Fluorescent Probes for Lipid Bilayers

“…Substituents on the imide nitrogen atoms of PDIs tend to improve solubility26, 27 while retaining the planarity of the perylene aromatic ring system, thus preserving the perylene's optical properties 28. N‐substitution of PDIs can also influence their self‐assembly properties, which has stimulated intensive studies into bulk and solution‐based applications of these compounds 29, 30, 31, 32. By contrast, substitution of the perylene ring system at either the ortho ‐ or bay positions can significantly influence the optical and solubility properties of the PDIs, dependent upon the substitution pattern, the steric bulk and electronic properties of the substituent group 33, 34, 35, 36.…”

“…[28] N-substitution of PDIs can also influence their self-assembly properties, which has stimulated intensive studies into bulk ands olution-based applicationso ft hese compounds. [29][30][31][32] By contrast, substitution of the perylener ing system at either the ortho-o rb ay positionsc an significantly influence the optical and solubility properties of the PDIs, dependent upon the substitution pattern, the steric bulk ande lectronic properties of the substituent group. [33][34][35][36] Bay substitution, for example, increases steric hindrance in this region of the molecule, which is relieved by out-of-plane twisting of the PDIs perylene ring system.…”

Improving the Quantum Yields of Perylene Diimide Aggregates by Increasing Molecular Hydrophobicity in Polar Media

“…Although morphology control has been studied for a variety of PDI systems, many of the approaches used to control aggregation have been performed in halogenated or organic solvents. There has been an increasing interest in creating PDIs that are soluble in aqueous or more polar solvents . Many of these molecules use hydroxy‐terminated, large dendritic or oligosilsesquioxane groups to deter aggregation and dimerization of the PDIs in these solutions.…”

“…[12,13] The aggregate morphology andc rystal structure can also be controlled. [14][15][16][17][18][19][20][21][22] PDIs can interactt oc reate chiral or helical structures, [23] wires, [20,24] "fish-tail" structures, [25] liquid crystal phases, [26] self-assembled mixed aggregates, [27][28][29] and crystallites of varying degrees of disorder. [30,31] These molecular morphologyand electronic modificationshave facilitated many potential materials applications.…”

“…[2,17,[32][33][34] Although morphology control has been studied for av ariety of PDI systems, many of the approaches used to control aggregation have been performed in halogenated or organic solvents.T here has been an increasing interest in creating PDIs that are soluble in aqueous or more polar solvents. [18,19,[35][36][37][38][39][40] Many of these molecules use hydroxy-terminated, large dendritic [41] or oligosilsesquioxane [42][43][44] groups to deter aggregation and dimerization of the PDIs in these solutions. The use of less toxic mediai np roducing optoelectronic devices, such as plastic solarc ells, would improve the overall fabrication capabilities of these systems.…”