Oxidative additions of dichloromethane and cyclo-octasulfur to rhodium(I) complexes containing (2-aminoethyl)-dimethylphosphine or -diphenylphosphine
Abstract
The oxidative-addition reactions of dichloromethane and
cyclo-octasulfur with rhodium(I) complexes
containing (2-aminoethyl)dimethylphosphine (edmp) or
(2-aminoethyl)diphenylphosphine (edpp) have been examined. The reactions
of [{RhCl(cod)}
2
]
(cod = cycloocta-1,5-diene) with edmp and with edpp in
dichloromethane yield cationic adducts
trans(Cl,C)cis(P,P
′)-[RhCl(CH
2
Cl)(edmp)
2
]
+
1 and
trans(Cl,C)cis(P,P
′)-[RhCl(CH
2
Cl)(edpp)
2
]
+
2, respectively. X-Ray analyses of these complexes revealed
that the Rh–Cl bond lengths are considerably elongated compared
with those of the corresponding dichloro complexes
trans(Cl,Cl′)cis(P,
P′)-[RhCl
2
(edmp)
2
]
+
and
trans(Cl,Cl′)cis(P,
P′)-[RhCl
2
(edpp)
2
]
+
due
to the strong trans influence of the chloromethyl donor group.
The Rh–C bonds in complexes 1, 2 and
trans-[RhCl(CH
2
Cl)(dmpe)
2
]
+
are 2.050(7) < 2.078(7) < 2.162(2)
Å, respectively. This order reflects the differences in
the steric bulk around rhodium(III) centre as well as the
strength of the trans influence toward the
trans-positioned Rh–Cl bond. Complex 2 reacted
further with S
8
to give a mixture of
trans(P,N)-[Rh(S
4
)(edpp)
2
]
+
3a and
trans(P,N)-[Rh(S
5
)(edpp)
2
]
+
3b, however such a reaction does not occur
for 1. On the other hand, direct addition of S
8
to
[Rh(edmp)
2
]
+
in methanol resulted in the formation
of
trans(N,N′)-[Rh(S
4
)(edmp)
2
]
+
4a and a small amount of the
S
5
complex 4b. The analogous reaction with
[Rh(edpp)
2
]
+
gave a mixture of 3a and
3b. X-Ray analyses revealed that 3a and 3b
are cocrystallized in the ratio of 1∶1. The preparation of
trans(N,N
′)-[Rh(O
2
)(edmp)
2
]
+
5 is also described.
′)-[Rh(O
2
)(edmp)
2
]
+
5 is also described.
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