Chemistry Reference
In-Depth Information
Figure 4.31
Pr
3
3
-O
2
-O
3
O
4
core structure of [Pr
3
3
-tftb
2
-
tftb
3
tftb
4
] (tftb D OC
CH
3
2
CF
3
;
C
CH
3
2
CF
3
groups omitted).
Figure 4.32
Nd
6
6
-Cl
3
-O
2
-
O
9
O
6
core structure of [Nd
6
6
-
Cl
3
-OPr
i
2
-OPr
i
9
OPr
i
6
]
( D Nd
,
ž
D Cl).
2.7.4
Neodymium
The first structurally characterized neodymium alkoxo compound reported was the
6
-
Cl centred complex [Nd
6
6
-Cl
3
-Pr
i
2
-OPr
i
9
OPr
i
6
] (Fig. 4.32).
129
The central
chloride ion is surrounded by a trigonal prism of neodymium ions. Each Nd has one
terminal isopropoxo ligand
trans
to the chloride, with four bridging isopropoxides making
a distorted octahedral coordination. It was noted by Evans and Sollberger
107
that this struc-
ture was related to the trinuclear [Y
3
3
-OBu
t
3
-Cl
-OBu
t
3
OBu
t
4
(thf)
2
], which
by the replacement of the THF molecules and addition of a trinuclear [Y
3
-OBu
t
-OBu
t
3
OBu
t
5
] moiety would give the [M
6
6
(Cl)
3
-OBu
t
2
-OBu
t
9
OPr
i
6
]
structure. The functionalized chelating ligand OCMe
2
CH
2
PMe
2
formed a mononuclear
six-coordinated Nd(
III
) complex [Nd
OCMe
2
CH
2
PMe
2
3
] with the facial configuration
isostructural with the yttrium analogue.
105
The mixed ligand chloride-bridged dimer
[Nd
2
-Cl
2
OCBu
t
3
4
(thf)
2
] exhibits a five-coordinated neodymium (data in
Table 4.7).
130
With acetonitrile as the supplementary ligand the mononuclear complex
[Nd
OCBu
t
3
3
MeCN
2
] was obtained with a trigonal bipyramidal Nd with the “tritox”
ligands in the equatorial plane.
131
The homoleptic complex [Nd
4
-ONp
8
(ONp)
4
]forms
a tetranuclear species with five-coordinate (square pyramidal) Nd which is isostructural
with the La analogue (Fig. 4.26).
118
With the “ditox” ligand OCHBu
t
2
the unsymmetrical
