Abstract
Mild thermolysis of a toluene solution of [(η
5
-C
5
H
5
)Mo(CO)
3
(C&z.tbd;CPh)] and [Fe
3
(CO)
9
(μ
3
-E)
2
] (E = S, Se) resulted in the formation of mixed-metal clusters, [(η
5
-C
5
H
5
)
2
Mo
2
Fe
3
(CO)
8
(μ
3
-E)
2
{μ
5
-CC(Ph)CC(Ph)}] (E = S,
1
; Se,
2
), [(η
5
-C
5
H
5
)
2
Mo
2
Fe
4
(CO)
9
(μ
3
-E)
2
(μ
4
-CCPh)
2
] (E = S,
3
; Se,
4
) and [(η
5
-C
5
H
5
)
2
Mo
2
Fe
3
(CO)
7
(μ
3
-E)
2
{μ
5
-CC(Ph)C(Ph)C}] (E = S
5
; E = Se
6
) which feature head-to-tail coupling of two acetylide groups, two acetylide groups which remain uncoupled and a tail-to-tail coupling of two acetylide groups, respectively, on the chalcogen-bridged Fe Mo cluster framework. Under similar conditions, the reaction of [(η
5
-C
5
H
5
)W(CO)
3
(C&z.tbd;CPh)] and [Fe
3
(CO)
9
(μ
3
-E)
2
] formed the clusters [(η
5
-C
5
H
5
)
2
W
2
Fe
3
(CO)
7
(μ
3
-E)
2
(μ
3
-η
2
-CCPh)(μ
3
-η
1
-CCH
2
Ph)] (E = S,
7
or Se,
8
) and [(η
5
-C
5
H
5
)WFe
2
(CO)
8
(μ-CCPh)] (
9
). All compounds have been characterised by IR and
1
H and
13
C NMR spectroscopy. The Se-bridged compounds have been further characterised by
77
Se NMR spectroscopy. The crystal structures of
1
,
3
and
5-9
were elucidated by X-ray diffraction methods.
Under mild thermolytic conditions, new chalcogen-stabilised mixed Fe Mo clusters are obtained which feature acetylide groups coupled in a head-to-head fashion, two acetylide groups which remain uncoupled and a tail-to-tail coupling of two acetylide groups.