Chemistry Reference
In-Depth Information
Figure 4.53
Structure of [fCo
8
-OMe
16
O
2
CMe
8
g
NH
4
]
(
ΕΎ
D N of guest NH
4
).
The tetranuclear species [Co
4
3
-OMe
4
2
-chp
chp
3
MeOH
7
] (hchpD 6-chloro-
2-pyridone) has been obtained. The molecule contains a cubane-like Co
4
3
-OMe
4
unit.
395
The remarkable octanuclear molecule [Co
8
-OMe
16
,
2
-O
2
CMe
8
]hasa
symmetrical toroidal shape containing the eight Co atoms in a plane octagon formed
from four [Co
2
-OMe
2
-O
2
CMe
] units, forming eight edge-shared distorted CoO
6
octahedra (Fig. 4.53). An NH
4
ion is sequestered into the centre of the toroidal
molecule and is counterbalanced by a PF
6
anion in the crystal.
396
2.14.2
Iridium and Rhodium
In the salt [IrH
OMe
PMe
3
4
]
C
PF
6
the Ir(
III
) is octahedrally coordinated with
hydride and methoxide
cis
to each other.
397
Other Ir(
III
) complexes characterized
are the five-coordinated [Ir
OCH
2
CF
3
H
2
fP
C
6
H
11
-
c
3
g
2
] and the six-coordinated
[Ir
OCH
2
CF
3
H
2
fP
C
6
H
11
-
c
3
g
2
CO
] (Table 4.13, p. 323).
398
The Rh(
I
) alkoxide
[Rh
OCH
2
CF
3
PMe
3
3
] has the expected square planar configuration.
399
2.15
Alkoxides of Nickel, Palladium, and Platinum
2.15.1
Nickel
Several alkoxo complexes of nickel have been structurally characterized.
One of the first structures reported was that of the tetranuclear [Ni
4
-
OMe
4
EtOH
4
OC
6
H
4
CHO
4
] which has a cubane-like Ni
4
-OMe
4
core. Each
