Ion-pair induced self-assembly in aqueous solvents

Abstract

The intriguing advantages of supramolecular chemistry and particularly the application of self-assembly for the construction of defined nanostructures from small, preferably synthetically easily accessible molecules has become a promising area of modern chemistry in the last years. However, the main focus of early work was based on H-bond induced self-assembly which is limited to nonpolar organic solvents. In the past years the field started to shift more and more towards obtaining self-assembling architectures in polar solvents and even water. This tutorial review will discuss some representative examples for self-assembling systems in polar solvents in order to illustrate the different concepts and strategies that can be used. We will also briefly discuss the special properties of water as the ultimate protic solvent from the perspective of a supramolecular chemist to elucidate the challenges that this solvent still poses even today to obtain specific self-assembled nanostructures.

Hydrophobicity and geometry: Water at curved graphitic-like surfaces and within model pores in self-assembled monolayers

“…A complete knowledge of the behavior of water at interfaces and under nanoconfinement is expected to open new roads of both academic and technological relevance in fields ranging from biology to materials science A c c e p t e d M a n u s c r i p t [1,2,3,4,5,6,7,8,9,10,11,12]. Both in biological organization and in the supramolecular self-assembly of materials, the nanoconfinement that arises upon the interaction of the different assembling units affects the thermodynamic properties of the hydration water, which usually must be removed for the process to take place [7].…”

Selective recognition of the di/trimethylammonium motif by an artificial carboxycalixarene receptor

“…10 In this more challenging medium, hydrogen bonding between host and guest will provide less impetus for binding. 11 As introduction of methyl groups to basic amino acid residues results not in a change of the overall charge but in more lipophilic side chains, C-H•••π interactions and the hydrophobic effect are having a substantial reinforcing effect on the complexation.…”

“…These include trimethyllysine (3), dimethyllysine (4), acetylcholine (5), choline (6), carnitine (7), meldonium (mildronate) (8), 4-dimethylaminopyridine (9), methyllysine (10) and lysine (11). Unless otherwise specified, racemic compounds are used in this study.…”

Ion pairing controls rheological properties of “processionary” polyelectrolyte hydrogels

“…As the chain is in poor solvent, electrostatic blobs have a low water content. Such a low polarity microenvironement is well known to enhance otherwise weak electrostatic interactions in protein folding or engineered self-assembly [42].…”