Related Experiment Video
Updated: Jun 25, 2026
16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Solvent-assisted organized structures based on amphiphilic anion-responsive pi-conjugated systems
Hiromitsu Maeda1, Yoshihiro Ito, Yohei Haketa
1College of Pharmaceutical Sciences, Institute of Science and Engineering, Ritsumeikan University, Kusatsu 525-8577, Japan. maedahir@ph.ritsumei.ac.jp
Chemistry (Weinheim an Der Bergstrasse, Germany)
|February 18, 2009
Summary
Researchers synthesized amphiphilic pi-conjugated oligopyrroles and formed solvent-assisted aggregates. These molecules self-assemble into nanoscale structures like networks and vesicles in aqueous solutions, influenced by peripheral substituents and solvent conditions.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Organic Chemistry
Background:
- Oligopyrroles are versatile pi-conjugated systems with potential applications in self-assembly.
- Amphiphilic molecules containing both hydrophilic and hydrophobic parts are key for forming organized structures.
- The design of acyclic anion receptors is crucial for developing responsive materials.
Purpose of the Study:
- To synthesize novel amphiphilic pi-conjugated acyclic oligopyrroles.
- To investigate the formation and characteristics of solvent-assisted aggregates and supramolecular assemblies.
- To explore the influence of peripheral substituents and solvent environments on aggregate structure and stability.
Main Methods:
- Synthesis of BF(2) complexes of 1,3-dipyrrolylpropane-1,3-diones with polyethyleneglycol (PEG) chains.
- Spectroscopic analyses (UV/Vis, fluorescence, (1)H NMR) to study aggregate formation.
- Dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo-TEM) for structural characterization.
- Solvent manipulation studies to investigate aggregate transformation and stability.
Main Results:
- Successful synthesis of amphiphilic oligopyrroles capable of forming supramolecular H-type assemblies in aqueous solution.
- Cryo-TEM revealed the formation of nanoscale network structures and vesicles, dependent on peripheral substituents.
- H-aggregates demonstrated sensitivity to solvent changes, transforming into monomers or J-type aggregates under specific conditions.
- Assemblies showed stability towards anion binding and exhibited solvent-dependent stacking modes.
Conclusions:
- Amphiphilic oligopyrroles can self-assemble into diverse nanoscale architectures in aqueous media.
- Water molecules play a crucial role in the formation of stable supramolecular assemblies.
- The observed assemblies are tunable and responsive to external stimuli like solvent composition and anion binding.
- These findings offer insights into the design of advanced functional materials based on pi-conjugated systems.
More Related Videos
Related Concept Videos
03:00Solubility
Solution, Solubility, and Solubility Equilibrium
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
01:30Micelles
Micelle formation is an intricate process that hinges on the properties of amphiphilic or amphipathic molecules and the conditions of the system in which they are found. Amphiphilic molecules, which have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts, play a critical role in this process.In aqueous environments, these molecules arrange themselves such that their hydrophilic heads are turned towards the water phase, while their hydrophobic tails are oriented away...
01:20Anionic Chain-Growth Polymerization: Overview
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
00:57Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...