SCHEDULED MAINTENANCE
Structural and electronic impact of fluorine in the ortho positions of the phenoxy groups of phenyl-phosphonite and -phosphinite ligands in compounds of platinum-group metals
Abstract
The phosphonites PPh(OPh)
2
I and
PPh(OC
6
H
3
F
2
-2,6)
2
II, and the phosphinites PPh
2
(OPh) III and
PPh
2
(OC
6
H
3
F
2
-2,6)
IV reacted with
[{RhCl(µ-Cl)(η
5
-C
5
Me
5
)
}
2
] to yield the complexes
[RhCl
2
L(η
5
-C
5
Me
5
)]
[L = PPh(OPh)
2
1,
PPh(OC
6
H
3
F
2
-2,6)
2
2, PPh
2
(OPh) 3 or
PPh
2
(OC
6
H
3
F
2
-2,6)
4]. The perprotio-phosphonite and -phosphinite, I and
III, reacted with
[{PtCl(µ-Cl)(PEt
3
)}
2
] to yield
exclusively the cis isomers of
[PtCl
2
(PEt
3
){PPh(OPh)
2
}]
5 and
[PtCl
2
(PEt
3
){PPh
2
(OPh)}]
7. The fluorine-containing phosphonite and phosphinite,
II and IV, reacted with
[{PtCl(µ-Cl)(PEt
3
)}
2
] to give the
trans isomers of
[PtCl
2
(PEt
3
){PPh(OC
6
H
3
F
2
-2,6)
2
}] 6a and
[PtCl
2
(PEt
3
){PPh
2
(OC
6
H
3
F
2
-2,6)}] 8a, which isomerize
slowly in acetone solution to yield the cis isomers 6b
and 8b. Values of
1
J(RhP) and
1
J(PtP) strongly suggest that the presence of
fluorine atoms in the ortho positions of the phenoxy groups has
a negligible effect on the electronic properties of the phosphorus atoms
of these ligands. X-Ray single-crystal structural studies on 1,
4, 6a, 6b, 7, 8a and
8b revealed that the fluorine atoms do, however, exert a
profound steric influence.
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