Chemistry Reference
In-Depth Information
Fig. 10 Fractional product distribution as a function of [L
6
]/[PPh
3
] as determined from frac-
tional ion intensities measured with ESI-MS. The symbols are assigned as follows:
red circles
,
[Au
8
L
6
4
]
2+
;
blue squares
,[Au
9
L
6
4
Cl]
2+
;and
green diamonds
,[Au
10
L
6
x
]
2+
(
x
¼ 4 and 5). See
[
142
] for more detail. Figure reproduced from [
142
]
nanoclusters were formed and the substitution of the solvent from neat chloroform
to a (50:50) methanol/chloroform solution assisted in both the stabilisation of the
clusters over time and the ESI ion current. They observed that using neat chloro-
form resulted in the decomposition of clusters over time and led to the formation of
a red precipitate which was soluble in methanol. Additionally, when the synthesis
was carried out in neat chloroform alone, the Au
11
cluster was formed in relatively
low abundance. In contrast, when the (50:50) methanol/chloroform solvent system
was used, the [Au
11
(L
3
)
5
]
3+
was present in greater intensity and the additional
clusters [Au
6
(L
3
)
3
]
3+
and [Au
8
(L
3
)
4
]
3+
were identified as minor components. This
refined solvent system was also applied to a synthesis of Et
2
P(CH
2
)
3
P(Et)
2
-
protected AuNCs [
150
] which were also studied via density functional theory
(DFT) calculations.
The reaction mechanisms that govern the formation of gold nanoclusters
protected by 1,3-bis(diphenylphosphino)propane were further elaborated by
Hudgens et al. [
117
], who recorded ESI-MS at various time intervals prior to and
after the addition of sodium borohydride.
Tsukuda et al. [
151
] have also shown that the dinuclear system Au
2
(BINAP)X
2
,
X
Cl or Br, can be treated with NaBH
4
to form monodisperse undecagold
clusters using either of
¼
)-2,2
0
-bis(diphenylphosphino)-
1,1
0
-binapthylene (BINAP), as revealed via ESI-MS, which gave the ions as
[Au
11
(BINAP)
4
X
y
]
z
+
(X
the bidentate ligand (
¼
Cl or Br;
y
,
z
¼
1,2; 2,1), Fig.
12
.
