Chemistry Reference
In-Depth Information
Table 6.1
Metal - ligand bond lengths for mixed alkyl, aryloxides of niobium and
tantalum
Bond length ( A)
O
,
C
( A)
Compound
M-O
M-C
Ref.
[Ta
OC
6
H
3
Bu
t
2
-2,6
2
Me
3
]
1.930 (6)
1.945 (6)
2.14 (1)
2.14 (1)
2.25 (1)
0.24
i
[Ta
OC
6
H
2
Bu
t
2
-2,6-OMe-4
2
Me
3
]
1.925 (4)
2.151 (8)
2.169 (8)
2.219 (8)
0.25
i
[Nb
OC
6
H
3
Ph
2
-2,6
2
CH
2
C
6
H
4
Me-4
3
]
1.915 (2)
1.917 (2)
2.181 (3)
2.181 (3)
2.192 (4)
0.27
ii
[Ta
OC
6
H
3
Ph
2
-2,6
2
CH
2
C
6
H
4
Me-4
3
]
1.903 (4)
1.906 (4)
2.154 (7)
2.192 (4)
2.181 (3)
0.27
ii
[Ta
OC
6
H
3
Me
2
-2,6
2
CH
2
C
6
H
5
3
]
1.919 (4)
1.887 (4)
2.204 (7)
2.204 (6)
0.30
iii
[Ta
OC
6
HPh
2
-2,6-Me
2
-3,5
2
CH
2
SiMe
3
3
]
1.89 (1)
1.90 (1)
2.10 (2)
2.16 (2)
2.13 (1)
0.24
iv
[Ta
OC
6
HPh
2
-2,6-Pr
i
2
-3,5
2
CH
2
SiMe
3
3
]
1.922 (3)
1.908 (3)
2.121 (5)
2.130 (5)
2.180 (5)
0.23
iv
[Ta
OC
6
H
3
Ph
2
-2,6
3
CH
2
SiMe
3
2
]
1.912 (3)
1.918 (3)
1.930 (3)
2.090 (6)
2.122 (5)
0.19
iv
[Ta
OC
6
H
3
Me
2
-2,6
3
C
6
H
5
2
]
1.848 (5)
1.879 (4)
2.181 (6)
0.32
v
[Ta
OC
6
H
3
Pr
i
2
-2,6
3
C
6
H
5
2
]
1.852 (3)
1.881 (3)
1.880 (3)
2.206 (5)
2.209 (5)
0.34
v
[Ta
OC
6
H
3
Me
2
-2,6
4
Me]
1.899 (4)
2.15 (1)
0.25
iii
i
L. Chamberlain, J. Keddington, I.P. Rothwell, and J.C. Huffman,
Organometallics
,
1
, 1538
(1982).
ii
R.W. Chesnut, G.G. Jacob, J.S. Yu, P.E. Fanwick, and I.P. Rothwell,
Organometallics
,
10
, 321
(1991).
iii
L.R. Chamberlain, I.P. Rothwell, K. Folting, and J.C. Huffman,
J. Chem. Soc., Dalton Trans.
,
155 (1987).
iv
J.S. Vilardo,
M.A. Lockwood,
L.G. Hanson,
J.R. Clark,
B.C. Parkin,
P.E. Fanwick,
and
I.P. Rothwell,
J. Chem. Soc., Dalton Trans.
, 3353 (1997).
v
B.D. Steffey, P.E. Fanwick, and I.P. Rothwell,
Polyhedron
,
9
, 963 (1990).
distance found between alkyl and alkylidene derivatives of these metals,
cf.
distances
of 2.246 (12)
˚
Aand2
.
026
10
˚
Ain[Cp
2
Ta(CH
2
)(CH
3
)].
179
In the case of tungsten there are a variety of eighteen electron aryloxides
to consider. Some examples include the carbonyl anions [W(OAr)(CO)
5
]
,the
hydrido aryloxide [W(OPh)(H)
3
(PMe
3
)
4
], the cyclometallated derivatives [W(O-
1
-C
6
H
4
)(H)
2
(PMe
3
)
4
] and [W(O-
1
-C
6
H
3
Me-CH
2
)(H)
2
(PMe
3
)
4
] and the chelated
2,6-diphenylphenoxides [W(OC
6
H
3
Ph-
6
-C
6
H
5
)(H)(PMePh
2
)
2
] and [W(OC
6
H
3
Ph-
6
-
C
6
H
5
)(Cl)(PMePh
2
2
] (Table 6.3). For all these compounds the W-OAr distances fall
