Fast Assembling of Magnetic Iron Oxide Nanoparticles by Microwave-Assisted Copper(I) Catalyzed Alkyne–Azide Cycloaddition (CuAAC)

Abstract

Two dimensional (2D) nanoparticles (NP) assemblies have become very attractive due to their original collective properties, which can be modulated as a function of the nanostructure. Beyond precise control on nanostructure and easy way to perform, fast assembling processes are highly desirable to develop efficient and popular strategies to prepare systems with tunable collective properties. In this article, we report on the highly efficient and fast 2D assembling of iron oxide nanoparticles on a self-assembled monolayer (SAM) of organic molecules by the microwave (MW)-assisted copper(I) catalyzed alkyne−azide cycloaddition (CuAAC) click reaction. Microwave irradiation favors a dramatic enhancement of the assembling reaction, which was completed with maximum density in NPs within one hour, much faster than the conventional CuAAC click reactions that require up to 48 h. Moreover, the MWassisted click reaction presents the great advantage to preserve specific reactions between alkyne and azide groups at SAM and NP surfaces, respectively, and also to avoid undesired reactions. To the best of our knowledge, this is the first time this approach is performed to nanoparticles assembled on surfaces.

Building high-coverage monolayers of covalently bound magnetic nanoparticles

“…This shows that the sonication cleaning and rinsing steps taken to remove physically adsorbed particles and catalyst (as also confirmed by XPS studies) are sufficient, and magnetic properties of the nanoparticles do not preclude one from effective completion of this step. The coverage of the monolayer produced with this method is very high, especially when compared to those from similar systems reported in the literature [19]. The improvement in coverage is thought to be, in part, attributed to the functionalization scheme of the substrate and will be discussed in detail below.…”

“…Toulemon et al has achieved this by attaching magnetic iron oxide nanoparticles to a gold substrate using a stirring procedure [18], and at an accelerated rate, by microwave irradiation [19]. Similarly, Upadhyay et al has formed covalently-bound nanoparticle layers using a variety of metallic, inorganic, and semi-conductor materials through the use of this “click” reaction in a dipping procedure [20].…”

Metal-catalyzed azide-alkyne “click” reactions: Mechanistic overview and recent trends

“…The use of microwaves was a valuable assistance in CuAAC reactions upon considerably shortening reaction times, and it improved yield [20,127c,165]. Perics's group reported the synthesis of tris(triazolyl)methane ligands [166] with CuCl for [167], recoverable and recyclable Cu/SiO 2 composite for eco-friendly multicomponent synthesis of 1,2,3-triazoles [168], "copper-in-charcoal" catalyzed triazole click reactions [169], palladium and copper-supported on charcoal as heterogeneous multi-task catalysts for sequential Sonogashira-click and click-Heck reactions [170], Cu/porous glass catalyst for CuAAC in water [165c], CuNPs supported on nano-Fe 3 O 4 -glutathione (Cu/nano-FGT) for one-pot multicomponent synthesis of 1,2,3-triazoles [171], and Fe 3 O 4 -supported CuBr catalysts for one-pot and scale-up synthesis of 1,2,3-triazoles (Fig. 32) [172].…”

Electrochemical nanoarchitectonics and layer-by-layer assembly: From basics to future

“…To perform CuAAC, catalytic quantities of Cu(I) ions are introduced by using Cu(I) salts or by in situ reduction of Cu(II) with sodium acetate. Other triggers for generation of the requisite Cu(I) cations include UV-irradiation [325,326], ultrasound [327], microwaves [328,329] and electro-chemical [330] stimuli. This latter electrochemical approach allows a reagent-free functionalization of surfaces and has met with great interest in the research community.…”