Chemistry Reference
In-Depth Information
Fig. 27 Cluster size-
dependent hydrogen
saturation at
T
R
¼
100 K
and minimum-energy
structures of the
investigated cluster sizes.
'Corner' site atoms are
indicated by filled circles.
For the case of Au
6
+
, the
two lowest-energy isomers
are displayed with the
nontriangular incomplete
hexagonal (ih) isomer being
0.19 eV higher in energy
than the triangular (t) one.
Figure reproduced from
[
271
]
size-dependent hydrogen saturation, which nicely matches the numbers of corner
sites available for the lowest-energy structures of the clusters as shown in Fig.
27
.
Reactions with N
2
O
The reactions of small gold cluster cation with N
2
O have been studied in an ion-trap
mass spectrometer [
272
]. Au
2
+
reacts with N
2
O to yield NO
+
as the major product
(Eq. (
18
)). In contrast, Au
3
+
reacts via adduct formation to give Au
3
N
2
O
+
(Eq. (
19
))
and via O atom abstraction to yield Au
3
O
+
(Eq. (
20
)). The former channel operates
for Au
4
+
:
Au
2
þ
NO
þ
þ
N
2
O
!
Au
2
N
ð
18
Þ
Au
3
þ
Au
3
N
2
O
þ
N
2
O
!
ð
19
Þ
Au
3
þ
Au
3
O
þ
þ
N
2
O
!
N
2
ð
20
Þ
Reactions with NH
3
and CH
3
NH
2
Pronounced odd versus even electron effects have been observed in the reactions of
gold cluster cations, Au
x
+
, with ammonia and methylamine [
282
]. Slow association
reactions are observed for
x
¼
1 and 3 (Eq. (
21
)), whereas Au atom displacement
was observed for
x
¼
2 and 4 (Eq. (
22
)). The primary product for
x
¼
4 undergoes
further cluster degradation via loss of Au
2
(Eq. (
23
)):
Þ
þ
Au
x
þ
RNH
2
!
ð
ð
Þ
Au
x
RNH
2
21
