ABSTRACT
Several reviews appeared in the last years to emphasize the unique
properties showed by gold metal when the particle size falls in
the nanometer range [1-5]. Au nanoparticles (NPs) have found
uses in ceramics, medicine, and other areas. Among them the most
exciting and growing field of application is undoubtedly catalysis.
Historically, gold was regarded to be catalytically inert, since the
discoveries made by Haruta [6] and Hutchings [7] in the late 1980s.
Surprisingly, they demonstrated simultaneously and independently
that supported gold NPs are the best catalyst for low-temperature
CO oxidation and ethyne chlorination to vinyl chloride. In recent
years, it has been shown that gold becomes active for many novel
reactions of synthetic interest when stabilized in the form of
NPs deposited on several organic and inorganic supports [2, 4].
Supported Au NPs have found numerous applications as unique
catalysts in aerobic oxidative processes [8-11], reduction of organic
compounds [12, 13], and C-C coupling reactions [14]. Moreover,
the ability of gold to coordinate with triple bonds has no parallel
with other transition metals. Upon coordination and formation of
the corresponding adduct, the alkyne becomes activated and more
reactive toward nucleophiles such as alcohols [15], amines [16], and
hydrosilanes [17].
