Chemistry Reference
In-Depth Information
d
n
9
r
4
n
g
|
5
Figure 3.10 Functionalization scheme of carbon materials: the obtained modified
surfaces present either chelating phosphines or charged ammonium
groups.
Reproduced from ref. 85.
carbon nanotubes functionalization strategy using radicals that could also
be used to anchor mixed-metal clusters as precursors of carbon-supported
nanoparticles.
86
As a final illustration, it is worth noting that other authors have also used
clusters as precursors of magnetic nanoparticles, supported or unsupported. In
the unsupported case, mixed-metal clusters such as [FeCo
3
(CO)
12
]
,
[Fe
3
Pt
3
(CO)
15
]
2
,[FeNi
5
(CO)
13
]
2
or [Fe
4
Pt(CO)
16
]
2
were used for example as
precursors of FeCo3, FePt, FeNi4 and Fe4Pt 5-10 nm sized nanoparticles.
87
In a
typical synthesis, oleic acid and trioctylphosphine oxide are dissolved in an-
hydrous 1,2-dichlorobenzene (DCB) and heated to 186 1C, before rapid in-
jection of the cluster dissolved in DCB with vigorous stirring, which are the
typical reaction conditions for the preparation of ligand-stabilized nano-
particles. Characterization with a SQUID magnetometer revealed that the ob-
tained nanoparticles are superparamagnetic at room temperature. In the
supported case, mesoporous supports such as xerogel or MCM-41 were im-
pregnated with the [NEt
4
][Co
3
Ru(CO)
12
] cluster, followed by heating under inert
atmosphere to give highly dispersed magnetic nanoparticles.
88
Notably, the
experimental conditions were milder than if using metal salts as precursors.
.
3.3.4.4 Ligand-stabilized Nanoparticles as Precursors of 'Naked'
Supported Nanoparticles
Before ending this chapter, it is worth mentioning that several authors
came up with the idea of preparing supported catalysts from preformed
ligand-stabilized nanoparticles. The experimental methodology involves the
Search WWH ::
Custom Search