Hydrazido(2-) complexes of niobocene
Abstract
The new compounds
[Nb(η-C
5
H
4
R)(η-C
5
H
4
R′)Cl(NNMe
2
)] (R = H or Me;
R′ = H or Me),
[Nb(η
5
-C
5
H
4
R)
2
(η
1
-C
5
H
4
R)(NNMe
2
)]
(R
3
= H
x
or
Me
y
,
x + y = 3),
[Nb{CMe
2
(η
5
-C
5
H
4
)(η
1
-C
5
H
4
)}(η
5
-C
5
H
5
)(NNMe
2
)] and
[Nb(η-C
5
H
5
)
2
(thf
)(NNMe
2
)][BPh
4
] (thf = tetrahydrofuran)
have been prepared. The crystal structure of
[Nb(η-C
5
H
4
Me)
2
Cl(NNMe
2
)]
has been determined. A variable-temperature NMR study of
[Nb(η
5
-C
5
H
5
)
2
(η
1
-C
5
H
5
)(NNMe
2
)] reveals a
fluxional interchange of the three cyclopentadienyl rings. This compound
has been shown to react with the electrophiles SiMe
3
Cl,
FeCl
2
·1.5thf, [NMe
3
H]Cl and
[Nb(η-C
5
H
5
)Cl
2
(NNMe
2
)]
to form in each case
[Nb(η-C
5
H
5
)
2
Cl(NNMe
2
)].
A variable-temperature NMR study of
[Nb{CMe
2
(η
5
-C
5
H
4
)(η
1
-C
5
H
4
)}(η
5
-C
5
H
5
)(NNMe
2
)] shows the presence of
two interconvertible diastereomers. The bis- and tris-cyclopentadienyl
compounds have been shown to undergo exchange of their cyclopentadienyl
rings in solution with each other or Li(C
5
H
4
R).
The compound
[Nb(η-C
5
H
5
)(OBu
t
)
2
(NNMe
2
)] has also been shown to undergo a cyclopentadienyl
ligand-exchange reaction.
)(NNMe
2
)][BPh
4
] (thf = tetrahydrofuran)
have been prepared. The crystal structure of
[Nb(η-C
5
H
4
Me)
2
Cl(NNMe
2
)]
has been determined. A variable-temperature NMR study of
[Nb(η
5
-C
5
H
5
)
2
(η
1
-C
5
H
5
)(NNMe
2
)] reveals a
fluxional interchange of the three cyclopentadienyl rings. This compound
has been shown to react with the electrophiles SiMe
3
Cl,
FeCl
2
·1.5thf, [NMe
3
H]Cl and
[Nb(η-C
5
H
5
)Cl
2
(NNMe
2
)]
to form in each case
[Nb(η-C
5
H
5
)
2
Cl(NNMe
2
)].
A variable-temperature NMR study of
[Nb{CMe
2
(η
5
-C
5
H
4
)(η
1
-C
5
H
4
)}(η
5
-C
5
H
5
)(NNMe
2
)] shows the presence of
two interconvertible diastereomers. The bis- and tris-cyclopentadienyl
compounds have been shown to undergo exchange of their cyclopentadienyl
rings in solution with each other or Li(C
5
H
4
R).
The compound
[Nb(η-C
5
H
5
)(OBu
t
)
2
(NNMe
2
)] has also been shown to undergo a cyclopentadienyl
ligand-exchange reaction.
Please wait while we load your content...
