The complex [RuCl
  2
(PPh
  3
)
  3
] reacted
with the 1,4,2-diphosphastibolyl ring anion
[P
  2
SbC
  2
Bu
  t
  2
]
  -
 (containing ca. 25% of the 1,2,4-triphospholyl anion
[P
  3
C
  2
Bu
  t
  2
]
  -
) to produce a cocrystallised mixture (crystal structure) of two
isomers of
[Ru(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)
  2
] with
[Ru(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)(η
  5
-P
  3
C
  2
Bu
  t
  
2
)]. Variable-temperature 
  31
P-{
  1
H}
NMR studies on the mixture show one of the isomers and the last complex
to be fluxional at room temperature. It is believed that an interring
Sb · · ·
 

Sb interaction in the other isomer restricts its fluxionality in
solution. The reaction of
[P
  2
SbC
  2
Bu
  t
  2
]
  -
 with FeCl
  2
 yielded only one isomer of the
heteroferrocene complex
[Fe(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)
  2
] which is also non-fluxional in solution and has a
similar oxidation potential to that of ferrocene itself. The
heteroruthenocene complexes
[Ru(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)(η
  5
-C
  5
R
  5
)]
(R = H or Me) were prepared by treating
[Ru(η
  5
-C
  5
R
  5
)(MeCN)
  3
]
[PF
  6
] (R = H or Me) with
[P
  2
SbC
  2
Bu
  t
  2
]
  -
. The analogous ferrocene complex
[Fe(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)(η
  5
-C
  5
Me
  5
)] (crystal
structure) was synthesized by treating a 1∶1 mixture of
[P
  2
SbC
  2
Bu
  t
  2
]
  -
 and Li(C
  5
Me
  5
) with half an equivalent of
FeCl
  2
. Treatment of
[M(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)(η
  5
-C
  5
Me
  5
)]
(M = Ru or Fe) with [W(CO)
  5
(thf

)]
(thf = tetrahydrofuran) formed the secondary co-ordination
complexes
[M(η
  5
-P
  2
SbC
  2
Bu
  t
  2
)(η
  5
-C
  5
Me
  5
){W(CO)
  
5
}] (M = Ru or Fe) in which the
W(CO)
  5
 fragment is η
  1
 ligated to the
phosphorus centre adjacent to the ring antimony centre. A
diphosphastibolyl-bridged cationic triple-decker complex
[(η
  5
-C
  5
Me
  5
)Ru(µ-η
  5
:
η
  5
-P
  2
SbC
  2
Bu
  t
  2
)Ru(η
  5
-C
  5
Me
  5
)][PF
  6
] was the product of the reaction of
[P
  2
SbC
  2
Bu
  t
  2
]
  -
 with 2 equivalents of
[Ru(η
  5
-C
  5
Me
  5
)(MeCN)
  3
]
[PF
  6
].