Reversible Assembly and Disassembly of Receptor‐Decorated Gold Nanoparticles Controlled by Ion Recognition

Abstract

The controlled assembly of randomly dispersed colloidal particles can provide access to materials with advanced optical and electronic properties while providing fundamental insights into self-assembly processes in nature and nanotechnology. Typically, self-assembled nanoparticles are prepared by exploiting electrostatic interactions, lithographic techniques, and covalently linked molecular scaffolds. This results in static morphologies that cannot be disassembled easily. On the other hand, having access to systems that can be assembled or disassembled in a controlled manner could allow for in-depth understanding of the nanoparticles as well as rational control over the morphology and fundamental properties of the resulting constructs. If the changes in aggregation are induced by a specific external chemical stimulus, it could also permit the development of new chemosensors. Here we demonstrate the reversible assembly and disassembly of gold nanoparticles achieved by modulating the noncovalent interactions between surface-bound calix[4]pyrroles and added bis-imidazolium cations. We also demonstrate the use of these nanoparticles in the selective sensing of anions.

New dimensions in calix[4]pyrrole: the land of opportunity in supramolecular chemistry

“…1). 45 Aer extensive study, Jonathan L. Sessler and teammates concluded that unsubstituted C4Ps exist in four different conformations, analogous to calix [4]arene (Fig. 2).…”

“…To tune the binding ability of C4Ps (hosts) with their guests (anions), researchers worldwide have designed and synthesized various b-substituted calix [4]pyrrole derivatives. For example, in 2011, Sessler's group synthesized b-octaalkyl-substituted C4P derivative 15 using N-tosylpyrrolidine pyrrole and acetone in satisfactory yield (Scheme 2).…”

“…To this end, the design as well as the construction of powerful receptors having exceptional applications such as sensing, recognition, and transport of anions has been considered to be of prime importance and the need of the hour by supramolecular chemists. Due to their unique conformations, structural diversity, and molecular recognition properties, calix [4]pyrroles (C4Ps) have been studied as modern generation host receptors in the arena of supramolecular chemistry. [4][5][6][7][8][9][10][11][12][13] C4Ps are synthetic non-planar, non-aromatic tetrapyrrolic macrocyclic receptors capable of binding an array of anions as well as neutral substrates through N-H hydrogen bonding.…”

“…Due to their unique conformations, structural diversity, and molecular recognition properties, calix [4]pyrroles (C4Ps) have been studied as modern generation host receptors in the arena of supramolecular chemistry. [4][5][6][7][8][9][10][11][12][13] C4Ps are synthetic non-planar, non-aromatic tetrapyrrolic macrocyclic receptors capable of binding an array of anions as well as neutral substrates through N-H hydrogen bonding. From a chemical viewpoint, in recent years, C4Ps have been explored as catalysts in preparative organic chemistry 14 and also as vital precursors for the generation of important organic molecules such as calixpyridines and calixpyridinopyrroles.…”

The Synthesis of Diamidediallylcalix[4]arene Derivatives as Ligand for Bromide Anion

“…[1][2][3][4] One of the main aspects of this multi-disciplinary field of chemistry is the design and creation of unusual compounds based on these receptors and sensors for biological and inorganic cation and anion. [5][6][7][8] It is known that compounds containing allyl group are good starting materials for polymerization reaction [9][10][11][12] and chiral molecules receiving, [13][14][15] but there are only few examples of such reactions in supramolecular chemistry.…”