Metal compounds nanoparticle assembly

Daniel M-C, Astruc D (2004) Gold nanoparticles assembly, suprrunolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology. Chem Rev 104 293-346 De Jongh LJ (ed) (1994) Physics and chemistry of metal cluster compounds. Kluwer, Dordrecht Di Francia G, Alfano B, La Ferrara V (2009) Conductometric gas nanosensors. J Sensors 659275(18)... 

For transition and precious metals, thiols have been successfully employed as the stabilizing reagent (capping reagent) of metal nanoparticles [6]. In such cases, various functionalities can be added to the particles and the obtained nanoparticles may be very unique. It is well known that thiols provide good self-assembled monolayers (SAM) on various metal surfaces. When this SAM technique is applied to the nanoparticle preparation, nanoparticles can be covered constantly by functionalized moieties, which are connected to the terminal of thiol compounds. 

Figure 10.14. Binary superlattices self-assembled from various combinations of magnetic, semiconducting, and metallic nanoparticles, (a-e) TEM micrographs of (001) planes of binary superlattices isostructural with the A1B2 compound, (f) A sketch of the A1B2 unit cell. (g,h) Depictions of the front and side views of the superlattice (001) plane, correspondingly. Reproduced from Ref. 24, Copyright 2006, with permission from the American Chemical Society.

So-called superlattices of 5mn alkylthiolate protected silver particles having truncated octahedral shapes as well as thiol-stabilized 5 6 mn gold particles can be obtained from solution. Fractional crystallization is a very usual method to separate chemical compounds from other compounds and impurities. Mixtures of thiolate stabilized gold nanoparticles between 1.5 and 3.5 nm could successfully be fractioned into real monodisperse species containing 140, 225, 314, and 459 atoms. 2D assemblies have also become available of these fcc-structured nanoparticles. The decisive criterion to successhilly fraction and crystallize metal nanoparticles is to protect them perfectly by strongly bound ligand molecules in order to avoid coalescence. 

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