Chemistry Reference
In-Depth Information
Fig. 6 (a) Time-dependent ESI-MS reaction of Au
38
(PET)
24
with excess TBBT. The doubly
charged region is shown. The three grey shadows indicate three groups of peaks: (
left
)
Au
36
(TBBT)
m
(PET)
24
m
,(
middle
)Au
38
(TBBT)
m
(PET)
24
m
,and(
right
)Au
40
(TBBT)
m
(PET)
24
m
.
The numbers on top of the mass peaks indicate the number of TBBT ligands (
m
) exchanged onto the
cluster; (b) corresponding UV-Vis spectra at different times taken parallel to the ESI-MS data.
Figure reproduced from [
92
]
Ph
2
P-(CH
2
)
n
-PPh
2
, where
n
1-6, in promoting the formation of 'size-selected'
monodisperse clusters. Table
1
summarises the types of bis(phosphino)alkane-
protected gold clusters that have been observed by ESI-MS. From Table
1
it is
evident that a variety of gold core nuclearities are observed, depending on the
bisphosphine ligand used. This size selectivity correlates to the variation in the
alkane chain of Ph
2
P-(CH
2
)
n
-PPh
2
, where
n
¼
1-6. In the next sections, literature
reports which have dealt with the three phases of bisphosphine-protected
nanoclusters growth are discussed.
¼
2.4.1 Pre-reduction Phase
Colton et al. [
143
] were the first to use ESI-MS to monitor the ligand exchange
reactions of ClAuPPh
3
with various monodentate and bidentate phosphine ligands
added at various concentrations. The aims of their study were to examine (1) the
identity and abundance of gold(I) complexes that undergo ligand exchange and
