Programming a Gold Nanocrystal to Recognize and Selectively Bind a Molecular Substrate in Solution

Abstract

Gold nanocrystals stabilized by a chemisorbed mixture of a long-chain alkane thiol, namely dodecanethiol (95%), and a long-chain dodecanethiol incorporating a receptor, namely 12-mercaptododecyl-1-uracil (5%), have been prepared. In solution, these nanocrystals recognize and selectively bind a long-chain alkane incorporating a complementary substrate, namely, N, N′-2,6-pyridinediylbis[undecamide].

Carbon Nanotube and Gold‐Based Materials: A Symbiosis

“…The stable dispersion of dodecanethiol-modified AuNPs was prepared by the method described by Brust et al [44] The nearly size-monodisperse fraction was subsequently modified by the exchange of the adsorbed thiol for thiol-incorporating crown molecules (dodecanethiol incorporating a crown moiety in the terminal position). [61] The MWNTs were modified by two amide-coupling reactions: the first was between the carboxy-modified MWNTs and ethylenediamine, and the second between the remaining amine of the coupled ethylenediamine and the cation precursor [N-(4-carboxydibenzylamine)carbamate]. For the templated self-assembly of a gold nanowire in solution, a dispersion of crown-modified AuNPs in chloroform was added to a freshly sonicated suspension of cation-modified MWNTs in chloroform.…”

Nanoparticles: Scaffolds for Molecular Recognition

“…Crown ethers, for instance, have been shown to be excellent receptors for ammonium ions forming inclusion complexes. [19] To integrate this motif into nanoparticle systems, the groups of Fitzmaurice and Stoddart have synthesized gold MPCs featuring dibenzo [24]crown-8 ether moieties on the surface. [20] Through NMR experiments it has been shown that these MPCs in fact form pseudorotaxanes on the surface by binding dibenzylammonium ions to an 86 % coverage ( Figure 5).…”

“…[21] In these studies silver nanoparticles featuring dilute (15 %) dibenzo [24]crown-8 groups embedded in a dodecanethiol monolayer were synthesized through placeexchange reactions. Addition of stoichiometric amount of a ditopic bis-ammonium salt led, as expected, to a slow formation of a larger aggregates composed of individual MMPCs linked through [3]pseudorotaxane complexes ( Figure 6).…”

“…The dibenzo [24]crown-8 units on silver nanoparticle surfaces were attached to the dibenzylammonium cations on silica surfaces though silane chemistry. The recognition of the silica nanospheres (180 nm in diameter) by silver nanoparticles (7 nm in diameter) led to the pseudorotaxane formation at the surface of the nanocrystals and subsequent aggregation ( Figure 7).…”

“…[24] These systems have been shown to recognize a complementary 2,6-diamidopyridine guest through a three-point hydrogen-bonding interaction.…”