Copper nanomaterials

Sol-gel and dip-coating procednres were apphed to prepare copper nanomaterials. Alnmina-snpported copper nanoparticles from Cn(acac)2 and Al(OPr-i)3 were synthesized by Kantam and coworkers by the aerogel procednre. The Cn-Al203 nanoparticles were characterized by several analytical methods and were snccessfuUy nsed as catalysts for the preparation of 1,2,3-triazoles by the reaction of terminal alkynes, NaN3 and alkyl/allyl halides. 

Approaches to Synthesis and Characterization of Spherical and Anisotropic Copper Nanomaterials... 

The present chapter cites more than 350 papers, and focuses specifically on nonoxidized, nonsupported Cu > nanosized particles and structures. Unlike the situation in the recent literature, we wiU not use the adjective metallic to qualify these nanophases. Attributing the metallic character to a novel copper nanomaterial should necessarily imply an assessment of its electron energy distribution. The chemical bond connecting a Hmited number of copper atoms clustered in the core of a NP and stabiHzed by an outer shell composed of other substances, can hardly be regarded as a metallic bond. 

In this chapter, when reporting on copper nanomaterials, we will implicitly focus on the nanostructure main part-the core. The existence of a relatively thin stabilizing shell (composed of organic stabilizers, copper oxide or hydroxide, chemi- or physisorbed solvent molecules, etc.) surrounding the NP core will be accepted as a natural consequence of both the size and the chemical reactivity of the copper phase. 

The number of studies published on the synthesis and characterization of copper nanomaterials has been growing exponentially in recent years indeed, a Uterature search over the period 1991-2007 returned more than 5000 papers and patents [2). 

We dearly admit that such a classification is not perfect, and that some interesting studies may have been omitted, due not only to the high number of publications existing but also to the organization chosen for the chapter. Nevertheless, the chapter presents a critical selection of citations taken from the greatest number of studies on Cu NPs referenced to date. It is the authors intention that the chapter should be considered as a basic aid for the reader who wishes to approach the microcosm of the synthesis and characterization of copper nanomaterials in a concise and schematic manner. 

The approaches to polymer-stabilized copper nanomaterials can be divided into three main classes (i) the so-called polyol process (ii) soft-template processes in which the polymer is employed (either as such or in combination with other capping agents), aiming exclusively at stabilization of the Cu phases and (iii) dendrimer-encapsulation. 

Finally, we would like to describe a potential real-world application of stabilized copper nanomaterials that, at present, we are studying in our laboratory. We have found that Cu NPs capped by quaternary anamonium salts can be used as nanoreservoirs for the controlled release of Cu ions, and can be used in this manner as tunable disinfecting agents. The tight control of bioactive ion release is essential when maintaining concentrations that will be efficient in terms of antimicrobial activity, yet not show toxicity towards humans [320]. This key property will surely afford interesting applications in areas such as health care, antibacterial textiles, food-packaging, paints and space exploration. 

I 2 Spherical and Anisotropic Copper Nanomaterials in Medical Diagnosis... 

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