Chemistry Reference
In-Depth Information
formed whilst crotonaldehyde coordinates in
2
-OC mode in [W
2
-
OCH
2
Bu
t
2
OCH
2
Bu
t
4
2
-OCHCH
ΕΎ
CHCH
3
2
].
331
In the diolate complex [W
2
-L
3
],
where L D 2,5-dimethylhexane-2,5-diolate, the molecule retains the ethane-like stag-
gered conformation with 3 eight-membered diolate rings spanning the metal - metal triple
bond (WW, 2.363 A) (Fig. 4.48).
332
In the dimethylamine adduct [W
2
-L
2
-
L
2
Me
2
NH
2
] there is one bridging diolate ligand and the other two each chelate one of
the metal atoms whilst the two amine ligands are
anti
to one another about the metal - metal
bond (WW, 2.320 A).
332
Reactions of W
2
OR
6
with CO have produced some interesting products. With
the isopropoxide the dinuclear complex [W
2
-OPr
i
2
-CO
OPr
i
4
py
2
](W-W,
2.499 A) was obtained. This molecule has the same confacial bi-octahedral structure as
the isomorphous molybdenum complex.
234
With W
2
OBu
t
6
the compound formed
[W
2
-OBu
t
2
-CO
OBu
t
4
]
333
which is isomorphous and isostructural with the
molybdenum analogue.
227
Also formed in the reaction of [W
2
OPr
i
6
py
2
] with CO is
the interesting complex [W
2
-OPr
i
2
OPr
i
4
CO
4
] in which an octahedral W
OPr
i
6
moiety acts as a bidentate bridge to the W
CO
4
moiety.
334
In this edge-sharing
bi-octahedral complex the bridges are very unsymmetrical with W-O bonds in the
W
OPr
i
6
moiety being shorter (1.96 A) than those in the W
-OPr
i
2
CO
4
moiety
(2.25 A).
Reaction of the alkylidyne complex [W
2
OBu
t
6
CMe
2
] with CO gave the unsym-
metrical complex [W
2
-OBu
t
,
4
-C
2
Me
2
OBu
t
5
CO
] composed of two trigonal
bipyramids joined by axial (
-OBu
t
) and equatorial (
-C
2
Me
2
) ligands. One W atom
is bonded to three terminal Bu
t
O ligands and the other to two terminal Bu
t
Oand
one CO ligand.
335
Addition of CO to [W
2
OBu
t
6
CNMe
2
2
] producing bridging
2
-
ketenyl ligands in the symmetrical dimer [W
2
,
2
-OCCNMe
2
2
OBu
t
6
].
335
With
[W
OPr
i
3
CNEt
2
py
2
]
[W
2
,
2
-
carbonylation
produced
the
symmetrical
Figure 4.48
Structure of
[W
2
OCMe
2
C
2
H
4
CMe
2
O
3
].
