Rhodium catalysed hydroformylation of alkenes using highly fluorophilic phosphines

Article abstract of DOI:10.1039/b510766k

Highly fluorophilic phosphines incorporating at least one aromatic ring containing two directly attached perfluoroalkyl groups have been synthesised, their partition coefficients (organic phase : fluorous phase) measured and their electronic properties probed using ¹J_PtP data for their trans-[PtCl₂L₂] complexes. These phosphines have been used as modifying ligands for the rhodium catalysed hydroformylation of 1-octene in perfluorocarbon solvents. Catalyst activity, regioselectivity and the levels of rhodium leaching to the product phase vary with the substitution patterns of the modifying ligands that do not correlate with the electronic properties or partition coefficients of these ligands, but can be interpreted in terms of differences in the resting states of the catalysts. The Royal Society of Chemistry 2005.

Full text of DOI:10.1039/b510766k

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F U L L P A P E R
Rhodium catalysed hydroformylation of alkenes using highly
fluorophilic phosphines
a
a
b
a
Dave J. Adams, James A. Bennett, David J. Cole-Hamilton, Eric G. Hope,*
a
a
b
a
Jonathan Hopewell, Jo Kight, Peter Pogorzelec and Alison M. Stuart
Department of Chemistry, University of Leicester, Leicester, UK LE1 7RH.
a
E-mail: egh1@le.ac.uk; Fax: + 44 116 252 3789
b
Catalyst Evaluation and Optimisation Service (CATS), School of Chemistry, University of St.
Andrews, St. Andrews, UK KY16 9ST
Received 28th July 2005, Accepted 22nd September 2005
First published as an Advance Article on the web 14th October 2005
Highly fluorophilic phosphines incorporating at least one aromatic ring containing two directly attached
perfluoroalkyl groups have been synthesised, their partition coefficients (organic phase : fluorous phase) measured
1
and their electronic properties probed using JPtP data for their trans-[PtCl
2
2
L ] complexes. These phosphines have
been used as modifying ligands for the rhodium catalysed hydroformylation of 1-octene in perfluorocarbon solvents.
Catalyst activity, regioselectivity and the levels of rhodium leaching to the product phase vary with the substitution
patterns of the modifying ligands that do not correlate with the electronic properties or partition coefficients of these
ligands, but can be interpreted in terms of differences in the resting states of the catalysts.
Introduction
high electron-withdrawing ability of the perfluoroalkyl groups
which has been shown to be beneficial in hydroformylation
reactions. Such phosphines also have the advantage that they
The formation of long chain linear aldehydes by hydroformyla-
tion using cobalt-based catalysts is a very important industrial
process for the production of plasticisers, soaps and detergents.
3
are highly fluorophilic {e.g. P(C
coefficient of 85 : 15 {perfluorodimethylcyclohexane(PP3) :
-4-CH CH
6
H
4
-4-C
6
F
13
)
3
has a partition
1
Although rhodium-based catalysts give higher selectivities and
reactivities in the laboratory than those used in the industrial
systems, they have not been employed industrially because
they decompose as the high boiling products are distilled away
from the reaction medium. Consequently, there is considerable
interest in developing alternative methodologies for catalyst–
product separation for this process. Horv a´ th and R a´ bai have
shown that fluorous biphasic systems can be highly successful
toluene} compared to 47 : 53 for P(C
6
H
4
2
2
C
6
F
13
)
3
}. In
an attempt to improve the retention of the fluorous-derivatised
rhodium hydroformylation catalysts in the fluorous phase, here
we report the preparation of a series of phosphines having two
directly attached perfluoroalkyl groups per aromatic ring and
their application in the rhodium-catalysed hydroformylation of
1
-octene in perfluorocarbon solvents.
2
in the separation of catalyst from products post-reaction, and
our work has been developed using triarylphosphines and by
working in neat perfluorocarbon solvents. We have recently
Results and discussion
3
commissioned a reactor in which the hydroformylation of
alkenes under fluorous biphase conditions can be carried out
over prolonged periods under continuous conditions with full
Bromobenzenes such as 1 (Scheme 1) have been reported by
10
a number of authors. In general, these have been prepared
by the copper-mediated coupling reaction of a perfluoroalkyl
iodide with a 1,3-dihalobenzene, followed by bromination using
4
recycling of the fluorous phase.
The critical factor in designing an efficient catalyst for
application in fluorous biphasic systems is the high solubility
of the catalyst in the perfluorinated solvent. In a rhodium-
NBS. For the C F13 analogue 1a, van Koten et al. found that the
6
separation of the bromobenzene and unreacted starting material
was very difficult and they were unable to purify this material
5
10a
catalysed hydroformylation system, the solubility is conferred
on the rhodium by the addition of perfluoroalkyl ‘ponytails’ to
the modifying phosphine ligands and, to date, only monodentate
phosphines with, at most, three ponytails have been evaluated
completely. However, Pozzi et al. have described the successful
preparation of the C 17 analogue 1c by the reaction of 1,3,5-
tribromobenzene with two equivalents of pentadecafluoro-n-
8
F
11
octyl iodide, and we have found that this method allows the
formation of analytically pure 1a and 1c in moderate yields.
Formation of a range of perfluoroalkylated phosphines was
achieved by lithiation of 1a or 1b {3,5-bis(trifluoromethyl)-
bromobenzene} at low temperature with n-BuLi followed
by quenching with either diphenylchlorophosphine, dichloro-
phenylphosphine or bis(4-tridecafluoro-n-hexylphenyl)chloro-
2–4,6
for hydroformylation in fluorous solvents.
However, whilst
the incorporation of further ponytails is expected to increase
the solubility of the phosphine and, hence, the catalyst in the
perfluorinated solvents offering better recovery and recyclability
under fluorous biphase conditions, there are few examples of
phosphines with more than three ponytails. Those reported in
7,8
12
the literature include perfluoroalkylated analogues of dppe,
phosphine (Scheme 1). In all cases, the reaction was com-
a ligand scaffold that affords poor regioselectivity in the
hydroformylation of alkenes, ligands incorporating a silyl spacer
group, which allows up to three ponytails per ring and, most
plicated by the low solubility of 1a at these low temperatures,
which necessitated the use of a very high dilution. Nonetheless,
this methodology has allowed the formation of one phosphine
with two perfluoroalkyl groups on the same aromatic ring, 2a,
and two phosphines with four perfluoroalkyl groups directly
attached to the aromatic rings in two different ways, 3a and 4a.
Unfortunately, all attempts at reaction of the aryl lithiate of 1a
8
recently, Sinou et al. have described a phosphine with two pony-
9
tails per ring incorporating OCH
2
spacer groups, which has also
been shown to offer poor regioselectivity in the hydroformyla-
6
tion of alkenes. We have been investigating phosphines incor-
porating perfluoroalkyl groups directly attached to the aromatic
with PCl
3
failed to give the desired tris-derivatised phosphine
ring i.e. with no additional spacer group in order to exploit the
with six ponytails. In contrast, the straightforward synthesis
3
8 6 2
D a l t o n T r a n s . , 2 0 0 5 , 3 8 6 2 – 3 8 6 7
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 5

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Scheme 1 (i) n-BuLi, ether; (ii) Ph
2
PCl; (iii) PhPCl
2
; (iv) ClP(C
6
H
4
-4-C
6
F
13
)
2
. (a) R
f
= C
6
F
13; (b) R
f
= CF
3
; (c) R
f
= C
8 17
F .
of P{C
6
H
3
-3,5-(CF
3
)
2
}
3
with six trifluoromethyl groups sug-
Table 1 Partition coefficients and electronic data for triarylphosphines
gests that this is a solubility or steric issue rather than an
a
1JPPt/Hzb
13
Phosphine
PPh
% Fluorine (w/w)
% Tol : % PP3
electronic one. The even lower solubility of 1c at low tem-
peratures actually precluded all of our attempts to prepare
phosphine ligands containing C
this methodology. Reaction of 1c with n-BuLi in ether, ether–
c
3
0
55
59
61
64
64
43
59
100 : 0
39 : 61
24 : 76
15 : 85
10 : 90
1 : 99
2635
6
H
3
-3,5-(C
8
F
17
2
) groups using
2
2
a
c
2692
2695d
2719
2741
2743
2739
2741
◦
hexane or ether–PP2 mixtures between −80 C and room
6 4 6 13 3
P(C H -4-C F )
3a
temperature only resulted in the virtual quantitative recovery
of the starting aryl bromide. Further experiments indicated
4
a
◦
3b
88 : 12
48 : 52
that, at low temperatures (−80 to −60 C), no reaction of 1c
4
b
with n-BuLi occurs such that, on addition of P–Cl reagents,
only butyl-derivatised phosphines are formed. In contrast, at
a
b
2 2
Determined gravimetrically. Coupling constant for trans-[PtCl L ]
◦
◦
c
d
higher temperatures (−60 to 0 C), lithiation at the 4-position
dissolved in CDCl
3
at 25 C. Data taken from ref. 20. Data taken
occurs preferentially over lithium-bromine exchange and the
resulting aryl lithiate is too sterically crowded to react with any
P–Cl reagent. Consequently, on work-up, the starting material
from ref. 15.
the perfluorinated solvents, with 4a having the highest reported
is regenerated or, following the addition of D O, the analogous
deuteride can be isolated (Scheme 2). An alternative strategy can
be employed for the synthesis of phosphine ligands containing
2
partition coefficient for any triarylphosphine, and rivalling
5
those for the trialkylphosphines. It is clear, however, that the
positioning of the fluorous ponytails on the triarylphosphines is
extremely important and that the presence of the underivatised
phenyl ring in 3a has a negative impact on its partition
coefficient, i.e. although 3a and 4a both have the same percentage
fluorine (w/w) and the same number of ponytails, 4a has a much
superior partition coefficient than 3a. In addition, the data for
C
6
H
3
-3,5-(C
8
F
17
) groups (Scheme 3) involving the copper-
2
mediated cross coupling reaction of the perfluoroalkyliodide
with an appropriately substituted bromoarylphosphine oxide
followed by reduction. However, our observations on the
influence of 3,5-disubstitution on the regioselectivity and metal
leaching levels in the rhodium-catalysed hydroformylation of
14
3b and 4b illustrate that, even with up to 59% w/w fluorine,
1
-octene in perfluorocarbon solvents (vide infra) indicated that
the CF groups are not sufficiently fluorophilic to confer high
3
this substitution pattern was unlikely to be beneficial for this
catalytic process, and we restricted work on this strategy to proof
of principle with the synthesis and characterisation of 2c.
solubility in perfluorocarbon solvents, limiting the applications
of complexes incorporating these ligands for catalysis under
fluorous biphase conditions (vide infra, Table 2).
As expected, the perfluoroalkyl groups have a substantial
effect on the electronic behaviour of the phosphine centres, and
1
we have evaluated this effect using the magnitude of the JPPt
coupling constants for trans-[PtCl
2
L
2
], (L = phosphine; Table 1),
since the corresponding cis complexes could not be formed for 3a
or 3b presumably due to steric constraints. This is consistent with
our earlier work where we have shown that, although exclusively
◦
Scheme 2 (i) n-BuLi, ether, −60 C; (ii) D
2
O.
cis-[PtCl
bis-derivatised para-substituted ligands {PPh
and PPh(C -4-C
}, inseparable mixtures of cis- and
trans-isomers were obtained in the same reaction with P(C
2
L
2
] are obtained from the reactions of the mono- and
2
(C -4-C
6
H
4
6
13
F )
15
6
H
4
6
F
)
13 2
6
4
H -
15
16
4
-C
6
F
13
)
3
,
PPh
2
(C
6
H
4
-3-C
6
F
13) and PPh(C
-3-C
6
H
4
-3-C
6
F
13
)
2
and
1
6
exclusively trans-[PtCl
2
L
2
] with P(C
6
H
4
6
F
13
3
) , as a conse-
quence of steric congestion. In all cases, a cumulative increase in
the magnitude of the coupling constant, in comparison to those
for triphenylphosphine and P(C
6
H
4
-4-C
6
F
13
) was observed as
3
Scheme 3 (i) n-BuLi, ether; (ii) Ph
2
PCl; (iii) H
, ether.
2 2 8
O ; (iv) C F17I, Cu, bipy,
◦
the number of perfluoroalkyl substituents increased. However, as
can be seen for the data for 3a and 4a, the electron-withdrawing
effect is independent of the position of the perfluoroalkyl groups
on the aryl rings. For comparison, we have also prepared
DMSO, C
6
H
5
F, 100 C; (v) HSiCl
3
The partition coefficients (Table 1) show that these method-
ologies can provide phosphines with extremely high affinities for
D a l t o n T r a n s . , 2 0 0 5 , 3 8 6 2 – 3 8 6 7
3 8 6 3

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a
Table 2 Hydroformylation of 1-octene at 20 bar CO–H
2
(1 : 1)
b
c
c
c
c
d
e
−1
f
Phosphine
P(C -4-C
Conv. (%)
Octane (%)
Isom (%)
Branched (%)
n-Nonanal (%) l : b
Rate constant (s
)
Rh loss
g
6
H
4
6
F
13
)
3
97.8
95.9
98.9
98.5
98.3
97.3
0.4
0.3
1.0
0.4
0.3
0.4
3.7
2.0
3.3
3.3
3.3
3.7
12.8
17.3
20.1
16.9
15.4
14.5
80.9
76.4
74.6
77.9
79.3
78.7
6.3
4.4
3.9
4.7
5.1
5.4
1.9
1.9
1.2
2.5
3.3
3.7
7292
nd
225700
7486
nd
2
3
4
3
4
a
a
a
b
b
nd
a
◦
2
Reaction conditions: solvent perfluoromethylcyclohexane (PP2; 4 ml); temperature 70 C; catalyst generated in situ from [Rh(CO) (acac)] and
b
c
ligand, Rh : P ratio 1 : 10; time 90 min. Conversion (100%−% residual 1-octene). Percentage of product by mole fraction. Isomerised products =
sum (2-, 3- and 4-octene), generally > 95% 2-octene; Branched products = sum (2-propylhexanal + 2-ethylheptanal + 2-methyloctanal), generally >
d
e
9
1
8% 2-methyloctanal. l : b = ratio of linear to all branched aldehyde products. All reactions were found to be 1st order in [1-octene] to over 80%
f
-octene consumption. Rhodium loss to the organic product as ppm by weight. nd = not determined; (organic phase deeply coloured due to the
g
presence of rhodium and, consequently, outside the range of the ICP-MS). Data taken from ref. 3.
analogues of 3a and 4a containing a number of CF
and 4b respectively. These data imply that, electronically, these
phosphines are almost identical to their C 13 counterparts,
confirming that the electronic influence of the perfluoroalkyl
substituents is independent of chain length.
3
groups, 3b
a catalyst is generated with a significantly higher rate constant
and greater selectivity to n-nonanal than that formed with 3a,
which is mirrored in the catalysts formed with 4a and 4b. Once
again, there is little difference in the electronic properties of the
6
F
1
phosphines, as measured by the JPPt coupling constants, which
These phosphines have been investigated in the hydroformy-
lation of 1-octene, Scheme 4 and Table 2, and the data
implies that the differences arise from the larger steric bulk of
the C F13 analogues.
6
3,4
compared directly with those for P(C
6
H
4
-4-C
6
F
13
)
3
.
As can be
seen, the bis-meta-perfluoroalkyl substitution results in catalysts
which are less selective to the desired linear aldehyde than
the para-substituted phosphines. However, it is clear that the
selectivity of the catalyst is not simply related to the electronic
environment of the phosphine since, despite the almost identical
Scheme 4 Rhodium-catalysed hydroformylation of 1-octene in perflu-
1
orocarbon solvents under 20 bar CO–H (1 : 1).
J
PPt values for 3a and 4a, the rates of reaction in the rhodium
2
catalysed hydroformylation of 1-octene using these ligands differ
dramatically and the l : b ratios are also different. It is known
that bulky phosphines can give rise to different mechanisms in
the hydroformylation of alkenes, resulting in lower selectivity
to the linear aldehyde, and it seems that 3a is sufficiently
bulky for this to occur. At the same time, despite it having
Conclusions
15
We have successfully prepared highly fluorophilic triaryl phos-
phines that feature at least one aromatic ring derivatised with
two directly attached perfluoroalkyl groups. The effect of the
ponytails on the electronic properties of the phosphine has been
found to be independent of the structure of the phosphine,
but highly dependent on the number of ponytails incorporated.
These fluorophilic phosphines have been used successfully for
the hydroformylation of 1-octene in fluorocarbon solvents, for
which the catalytic data are highly dependent on the structure of
the phosphine ligand, in particular the length and substitution
patterns of the perfluoroalkyl groups, which can be interpreted
in terms of the resting state of the metal catalyst. Further
spectroscopic work on these catalytic systems is in progress and
may shed further light on this interpretation.
a slightly higher partition coefficient than that of P(C
6
H
4
-4-
C
6
F
)
13 3
, significant leaching of rhodium into the product phase
occurs for ligand 3a. Initially this may seem slightly surprising,
but it could be accounted for in two ways. We have found that
the identity of the perfluorinated solvent has a negligible effect
when determining the partition coefficients, but the identity
of the organic solvent is critical. Here, following catalysis, the
catalyst partitions between perfluoromethylcyclohexane (PP2)
and, mainly, nonanals, whilst the partition coefficients were
measured in a toluene–PP3 biphase. Since nonanal is more polar
than toluene, it might be expected that retention of the catalyst in
the fluorous phase would actually be better and, certainly, should
affect both phosphines similarily. Therefore, the influence of the
ligand on catalyst leaching is more likely to be due to the resting
state of the catalyst. Several species are known to exist under
Experimental
General remarks
reaction conditions including [RhH(CO)(L)
3
], [RhH(CO)
2
(L) ]
2
17
1
19
31
and [RhH(CO)
3
(L)] (L = phosphines), and it is likely that,
H, F and P NMR spectroscopies were carried out
due to the steric bulk of 3a, the resting state of the catalyst is
on a Bruker ARX250 spectrometer at 250.13, 235.34 and
101.26 MHz or a Bruker DPX300 spectrometer at 300.14, 282.41
and 121.50 MHz respectively and were referenced to external
one which includes a smaller number of phosphines than that
derived from P(C
four perfluoroalkyl groups whilst P(C
6
H
4
-4-C
6
F
13
)
3
. Hence, although 3a contains
-4-C has only
1
19
31
6
H
4
6
F
13
)
3
SiMe
4
( H), external CFCl
3
( F) and external H
3
PO ( P)
4
three, it may well be that there is a significant difference in
the number of ponytails present in the catalyst resting states.
In addition, the presence of one phenyl ring with no ponytails
could also influence the large amount of leaching observed in
the case of 3a. For the catalyst generated with 4a, the impact of
the increased steric requirement appears to be closely matched
by the improved fluorophilicity of the additional perfluoroalkyl
group to give rhodium leaching levels comparable to those for
using the high frequency positive convention. Abbreviations for
NMR spectral multiplicities are as follows: s = singlet, d =
doublet, m = unresolved multiplet. Elemental analyses were
performed by the Elemental Analysis Service at the University
of North London. Mass spectra were recorded on a Kratos
12
Concept 1H mass spectrometer. (F13
C
6
-4-C
6
H
4
)
2
PCl and cis-
18
[PtCl
2
(MeCN) ]
2
were prepared by the literature routes. Gas
chromatographic analyses of the catalytic product mixtures were
carried out on a Hewlett-Packard 5890 series gas chromatograph
equipped with a flame ionisation detector. The gas chromato-
graph was interfaced with a Hewlett-Packard Chemstation
for the determination of peak areas by electronic integration.
P(C
6
H
4
-4-C
6
F
13
)
3
. The data for the CF -substituted ligands (3b
3
and 4b) confirm that these ligands are not suitable for catalysis
under fluorous biphase conditions and reinforce the implication
that steric congestion is an issue in these reactions. Using 3b,
3
8 6 4
D a l t o n T r a n s . , 2 0 0 5 , 3 8 6 2 – 3 8 6 7

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Concentrations of products were obtained by comparison of
peak areas with those obtained from standard solutions plotted
on a calibration graph. The method employed a Supelco
(4F, m, CF
−126.47 (4F, m, CF
2
), −122.05 (4F, m, CF
2
), −123.23 (4F, m, CF
) −4.0 (s).
2
),
3
1
1
2
). P{ H} NMR (C
6
D
6
TM
Meridian MDN-35 low polarity, cross-linked phase comprised
of a (35% phenyl)-methylpolysiloxane fused silica capillary
column (30 m × 0.25 mm × 0.25 lm). Rhodium analyses of
fractions recovered after the catalytic reactions were measured
by inductively coupled plasma mass spectrometry (ICP-MS)
on an Agilent 7500a instrument. The instrument was modified
Bis[3,5-bis(tridecafluoro-n-hexyl)phenyl]phenylphosphine, 3a
◦
mp = 56–58 C. Anal. Calc. for C42
H F52P: C, 32.86; H, 0.72.
+ 1
11
Found C, 32.72; H, 0.70. m/z (FAB) 1534 (M ). H NMR
CDCl ) 7.97 (2H, s, H-4), 7.89 (4H, s, H-2,6), 7.74 (1H, m,
(
3
19
1
PhH), 7.63 (2H, m, PhH), 7.55 (2H, m, PhH). F{ H} NMR
for direct analyses of the organic fractions by using O
2
as
4
(
CDCl
J
3
) −81.26 (12F, t, JFF = 10.0 Hz, CF
3
), −111.57 (8F, t,
a make-up gas to prevent carbon deposition on the sample
and skimmer cones. Platinum cones were used together with a
4
FF = 13.2 Hz, a-CF
m, CF
), −123.34 (8F, m, CF
NMR (CDCl
) −5.3 (s).
2
), −121.80 (8F, m, CF
2
), −122.39 (8F,
). P{ H}
31
1
2
2
), −126.58 (8F, m, CF
2
◦
self-aspirating nebuliser held at −5 C. Samples were diluted
3
by 10% in a mixture of xylene and toluene (50 : 50) and
ion counts were referenced against calibration curves obtained
from standard solutions of [Rh(acac)(CO)
2
] (acacH is 2,4-
Bis(4-tridecafluoro-n-hexylphenyl)-[3,5-bis(tridecafluoro-n-
hexyl)phenyl]phosphine, 4a
pentanedione) in xylene–toluene (50 : 50). Standard solutions
were run intermittently between samples to ensure that there
were no drifts in the instrument response and that the rate of
aspiration was constant.
Oil. Anal. Calc. for C42
H
11
F52P: C, 32.84; H, 0.72. Found C,
+ 1
33.03; H, 0.57. m/z (FAB) 1534 (M ). H NMR (CDCl
3
) 7.73
3
3
(
7
9
(
(
1H, s, H-4), 7.54 (6H, m, PhH), 7.32 (4H, t, JHH ≈ JHP
=
The partition coefficients were determined by dissolving
19
1
4
.8 Hz, H-2,6). F{ H} NMR (CDCl
3
) −81.50 (12F, t, JFF
=
0
.100 g of the required compound in a biphase consisting of
4
.0 Hz, CF
3
), −111.67 (4F, t, JFF = 14.0 Hz, a-CF
2
), −111.89
), −122.52
◦
toluene (2.00 ml) and PP3 (2.00 ml) at 25 C. This was stirred
for 20 min, allowed to settle for 30 min and a 1.00 ml aliquot
removed from each phase. The solvents were removed in vacuo
to constant weight.
4
4F, t, JFF = 15.0 Hz, a-CF
4F, m, CF
), −122.67 (4F, m, CF
126.82 (8F, m, CF
). P{ H} NMR (CDCl
2
), −122.02 (8F, m, CF
2
2
2
), −123.43 (8F, m, CF
2
),
31
1
−
2
3
) −6.3 (s).
1
0a
Bis[3,5-bis(trifluoromethyl)phenyl]phenylphosphine, 3b
Oil. Anal. Calc. for C22 12P: C, 49.44; H, 2.06. Found C,
9.51; H, 2.00. m/z (FAB) 534 (M ). H NMR (CDCl
3
,5-Bis(tridecafluorohexyl)bromobenzene, 1a
H F
11
A solution of C 13I (33.79 g, 0.076 mol) in DMSO (20 ml)
was added dropwise over 4 h to a stirred mixture of 1,3,5-
6
F
+
1
4
3
) 7.82
3
(
2H, s, H-4), 7.64 (4H, d, JHP = 6.6 Hz, H-2,6), 7.38 (3H, m,
tribromobenzene (12.01 g, 0.038 mol) and copper powder
1
9
1
◦
PhH), 7.26 (2H, m, PhH). F{ H} NMR (CDCl
3
) −63.04 (s).
(
9.64 g, 0.152 mol) in DMSO (60 ml) at 120 C. The mixture was
3
1
1
◦
P{ H} NMR (CDCl
3
) −3.9 (s).
stirred at 120 C for 12 h. After cooling to room temperature,
water (50 ml) and diethyl ether (50 ml) were added and the
mixture filtered. The organic layer was separated, washed with
and the solvent was
removed in vacuo. The off-white solid was distilled in a Kugelrohr
oven to yield the product as a colourless oil (bp 90–100 C,
.05 mmHg), which formed white crystals upon cooling. These
crystals were recrystallized in 80 : 20 ethyl acetate : acetonitrile
Bis(4-tridecafluoro-n-hexylphenyl)-[3,5-bis(trifluoromethyl)-
phenyl]phosphine, 4b
water (2 × 50 ml), dried over MgSO
4
◦
◦
mp = 63–64 C. Anal. Calc. for C32
H F32P: C, 37.14; H, 1.06.
+ 1
11
Found C, 36.97; H, 1.05. m/z (FAB) 1034 (M ). H NMR
CDCl ) 7.83 (2H, s, H-2,6), 7.69 (1H, s, H-4), 7.59 (4H, m,
0
(
3
1
9
1
◦
PhH), 7.34 (4H, m, PhH). F{ H} NMR (CDCl
3
) −63.00 (6F, s,
(
C
9.67 g, 0.012 mol, 32%). Mp = 39–41 C. Anal. Calc. for
4
4
CF
3
), −80.78 (6F, t, JFF = 9.3 Hz, CF
3
), −111.19 (4F, t, JFF
=
18
H BrF26: C, 27.24; H, 0.38. Found C, 26.94; H, 0.32. m/z
3
+ 1
13.6 Hz, a-CF ), −121.35 (4F, m, CF ), −121.97 (4F, m, CF ),
31 1
2 2
(
FAB) 792/4 (M ). H NMR (CDCl
3
) 7.86 (2H, s, H-2,6), 7.71
2
2
2
1
9
1
4
−122.78 (4F, m, CF ), −126.21 (4F, m, CF ). P{ H} NMR
(
1
1H, s, H-4); F{ H} NMR (CDCl
3
) −81.28 (6F, t, JFF
=
4
(CDCl ) −5.7 (s).
0.0 Hz, CF
3
), −111.50 (4F, t, JFF = 14.2 Hz, a-CF
2
), −121.81
3
(
4F, m, CF
2
), −122.11 (4F, m, CF
2
), −123.20 (4F, m, CF
2
),
−
126.57 (4F, m, CF ).
2
[
3,5-Bis(heptadecafluoro-n-octyl)phenyl]diphenylphosphine oxide
A solution of C 17I (5.46 g, 10 mmol) in benzotrifluoride
(10 mL) was added dropwise over 3 h to a stirred mixture of
General procedure for the preparation of phosphines. n-
BuLi (5.0 mmol, 1.6 M solution in hexanes) in diethyl ether
30 mL) was added dropwise over 1 h to a solution of the
required bromobenzene (5.0 mmol) in diethyl ether (150 mL)
8
F
19
(
Ph
2
PO(C
6
H
3
-3,5-Br ) (2.18 g, 5.00 mmol), activated copper
2
powder (2.25 g, 35.00 mmol) and bipy (0.17 g, 1.04 mmol) in
DMSO (5 mL) and benzotrifluoride (40 mL) under nitrogen at
◦
◦
at −78 C. This solution was then stirred at −78 C for 3 h.
◦
◦
The requisite chlorophosphine (5.0 mmol) or dichlorophosphine
120 C. The reaction was stirred and heated at 120 C for 167 h.
On cooling to room temperature the mixture was filtered, and
the filtrate washed with chloroform (2 × 20 mL), 1 M HCl (2 ×
50 mL) and water (50 mL). The organic layer was separated and
washed with water (2 × 20 mL). The aqueous layer was washed
with ether (2 × 50 mL) and the organic fractions were combined
(
(
2.5 mmol) was then added dropwise in a solution of diethyl ether
20 mL) over 1 h and the solution allowed to warm to room
temperature overnight. The solution was then washed well with
water, and the organic layer was separated, dried and the solvent
was removed in vacuo. The product was purified by passing
through a silica plug using petroleum ether as eluent to give the
phosphine in a 40–70% yield.
and dried over anhydrous MgSO . After filtration, the solvent
4
was removed in vacuo and the resulting solid recrystallised from
ethanol to give a white solid (1.80 g, 1.62 mmol, 32%). Mp 114–
◦
1
16 C. Anal. Calc. for C34
H F34OP: C, 36.62; H, 1.17. Found
13
[
3,5-Bis(tridecafluoro-n-hexyl)phenyl]diphenylphosphine, 2a
+ 1
C, 36.73; H, 1.01. m/z (EI) 1115 (MH) . H NMR (CDCl ) 8.05
3
◦
3
mp = 54–56 C. Anal. Calc. for C30
H
13
F
26P: C, 36.81; H, 1.33.
(2H, d, JPH = 11.4 Hz, H-2,6), 7.99 (1H, s, H-4), 7.57 (6H, m,
19 1
3
+
1
Found C, 36.85; H, 1.29. m/z (EI) 898 (M ). H NMR (CDCl
3
)
PhH), 7.45 (4H, m, PhH). F{ H} NMR (CDCl
) −80.81 (6F,
), −121.10 (4F,
), −126.20
4
7
(
9
.88 (1H, s, H-4), 7.59 (2H, s, H-2,6), 7.25 (6H, m, PhH), 7.18
m, CF
m, CF
(4F, m, CF
3
), −111.24 (4F, t, JFF = 14.0 Hz, a-CF
2
1
9
1
4
4H, m, PhH). F{ H} NMR (CDCl
3
) −81.17 (6F, t, JFF
=
2
), −121.89 (12F, m, CF
2
), −122.69 (4F, m, CF
) 27.1 (s).
2
4
31
1
.7 Hz, CF
3
), −111.49 (4F, t, JFF = 14.3 Hz, a-CF
2
), −121.80
2
). P{ H} NMR (CDCl
3
D a l t o n T r a n s . , 2 0 0 5 , 3 8 6 2 – 3 8 6 7
3 8 6 5

View Article Online
4
[
3,5-Bis(heptadecafluoro-n-octyl)phenyl]diphenylphosphine, 2c
Ph PO(C ) (0.50 g, 0.45 mmol) was dissolved
-3,5-{C
in dry and degassed toluene (20 mL), NEt (2.00 g, 2.81 mL,
0 mmol) was added and the stirred solution was heated to
(CDCl
3
) −63.20 (12F, s, CF
3
), −80.88 (12F, t, JFF = 9.9 Hz,
), −121.40 (8F, m,
), −126.06 (8F,
) 21.7 (s, JPPt = 2741 Hz, trans),
4
CF
CF
m, CF
3
), −111.45 (8F, t, JFF = 13.9 Hz, a-CF
2
2
6
H
3
8
F
17 2
}
2
), −121.93 (8F, m, CF
2
), −122.84 (8F, m, CF
2
3
3
1
1
1
2
). P{ H} NMR (CDCl
3
2
1
1
◦
15.7 (s, JPPt = 3599 Hz, cis).
20 C. HSiCl (0.91 g, 0.68 mL, 6.7 mmol) was added dropwise
3
over 2 h and the reaction mixture refluxed for a further 6 h.
The solution was then cooled in ice for 30 min and a saturated
Catalysis. An autoclave fitted with a substrate injector
containing 1-octene (1.0 mL, 6.37 mmol), a mechanical stirrer,
a gas delivery system, an injection port and a thermocouple was
solution of NaHCO (1 mL) was added. The solution was flushed
3
through a short alumina column using hexane (300 mL). On
evaporation of the solvent in vacuo a yellow solid was obtained
flushed with CO–H
romethylcyclohexane (PP2, 4.0 mL) containing dicarbonyl(2,4-
pentanedionato)rhodium(I) ([Rh(acac)(CO) ], 0.01 mmol) and
ligand (0.044 mmol) was added through the injection port
against a stream of CO–H using a syringe. The autoclave was
pressurised with CO–H (1 : 1) to 20 bar and the pressure
2
(1 : 1) to remove air. Degassed perfluo-
(
0.35 g, 0.32 mmol, 71%).
2
◦
Mp = 53–55 C. Anal. Calc. For C34
H F34P: C, 37.16; H,
+ 1
13
1
.18. Found C, 37.00; H, 1.17. m/z (FAB) 1098 (M) . H NMR
2
3
(CDCl
3
) 7.64 (1H, s, H-4), 7.58 (2H, d, JHP = 6.0 Hz, H-2,6),
2
1
9
1
7
.29 (4H, m, PhH) 7.21 (6H, m, PhH). F{ H} NMR (CDCl
3
)
released. This flushing procedure was repeated twice more. It
was repressurised to 16 bar, the stirrer was started (600 rpm) and
4
4
−
81.02 (6F, t, JFF = 10.5 Hz, CF
3
), −111.28 (4F, t, JFF
=
◦
1
4.2 Hz, a-CF
2
), −121.16 (4F, m, CF
2
), −121.95 (8F, m, CF
2
),
the autoclave was heated to 80 C for 45 min. The 1-octene was
−
122.29 (4F, m, CF
2
), −122.1 (4F, m, CF
2
), −126.33 (4F, m,
then added to the autoclave by forcing it in through the substrate
3
1
1
CF
2
). P{ H} NMR (CDCl
3
) −4.4 (s).
injector using a CO–H pressure of 20 bar. The data recorder
2
was started and the temperature, pressure in the autoclave and
pressure in a ballast vessel, from which gas was fed into the
autoclave through a mass flow controller to keep the pressure
within the autoclave constant at 20 bar, were monitored and
recorded every 5 s. After the gas uptake had become very slow
General procedure for the preparation of [PtCl
The phosphine (0.1 mmol) and [PtCl (CH CN)
2
L
2
] complexes.
2
3
2
] (0.05 mmol)
were dissolved in dichloromethane (10 ml) and refluxed for 2 h.
After cooling, the solvent was removed and the resulting solid
washed well with petroleum ether to give the product as a pale
yellow solid in 84–91% yield.
(
5–8 h), the stirrer was stopped and the autoclave was allowed to
cool. The gases were vented and the mixture was syringed into a
sample vial for analysis by GC. Kinetic data were obtained from
an analysis of the pressure drop in the ballast vessel.
cis- and trans-[PtCl
2
{Ph
2
P(C
6
H
3
-3,5-[C
6
F
13
]
2
)}
2
]
Anal. Calc. for C60
H
26
P
2
Cl
2
F
52Pt: C, 34.93; H, 1.26. Found C,
+
1
34.62; H, 1.18. m/z (FAB) 2026 (M–Cl) . H NMR (CDCl ) 7.96
3
Acknowledgements
(
4H, s, H-2,6), 7.75 (2H, s, H-4), 7.65 (8H, m, PhH), 7.46 (12H,
1
9
1
4
m, PhH). F{ H} NMR (CDCl
3
) −80.82 (12F, t, JFF = 9.8 Hz,
We thank the Lloyd’s Tercentary Foundation (AMS), the Royal
Society (EGH, AMS) and the EPSRC (DJA) for financial
support.
4
CF
CF
3
2
), −111.35 (8F, t, JFF = 13.9 Hz, a-CF
2
), −121.40 (8F, m,
), −122.10 (8F, m, CF
2
), −122.77 (8F, m, CF
2
), −126.19 (8F,
3
1
1
1
m, CF
1
2
). P{ H} NMR (CDCl
3
) 21.9 (s, JPPt = 2692 Hz, trans),
1
4.5 (s, JPPt = 3630, cis).
References
trans-[PtCl
2
{PhP(C
6
H
3
-3,5-[C
Cl PtF104: C, 30.24; H, 0.66. Found C,
0.12; H, 0.50. H NMR (PP3) 8.00 (8H, s, H-2,6), 7.82 (4H, s,
6
F
13
]
2
)
2
}
2
]
1
C. D. Frohling and C. W. Kohlpaintner, Applied Homogeneous
Catalysis with Organometallic Compounds, ed. B. Cornils and
W. A. Herrmann, VCH, 1999, vol. 1, p. 27.
Anal. Calc. for C84
3
H
22
P
2
2
1
2
(a) I. T. Horv a´ th and J. R a´ bai, Science, 1994, 266, 72; (b) I. T.
1
9
1
H-4), 7.69 (4H, m, PhH), 7.34 (6H, m, PhH). F{ H} NMR
´
´
Horvath, G. Kiss, R. A. Cook, J. E. Bond, P. A. Stevens, J. Rabai
4
(
CDCl
3
) −80.93 (24F, t, JFF = 8.5 Hz, CF
3
), −111.70 (16F, t,
), −122.06 (16F, m,
and E. J. Mozeleski, J. Am. Chem. Soc., 1998, 120, 3133.
4
J
FF = 14.2 Hz, a-CF
2
), −121.38 (16F, m, CF
2
3 (a) D. F. Foster, D. Gudmunsen, D. J. Adams, A. M. Stuart,
E. G. Hope, D. J. Cole-Hamilton, G. P. Schwarz and P. Pogorzelec,
Tetrahedron, 2002, 58, 3901; (b) D. F. Foster, D. J. Adams, D.
Gudmunsen, A. M. Stuart, E. G. Hope and D. J. Cole-Hamilton,
Chem. Commun., 2002, 722.
3
1
1
CF
2
), −122.77 (16F, m, CF
2
), −126.20 (16F, m, CF ). P{ H}
2
1
NMR (CDCl
3
) 22.5 (s, JPtP = 2741 Hz).
cis- and trans-[PtCl
Anal. Calc. for C84
2
{P(C
6
H
4
-4-C
Pt: C, 30.24; H, 0.66. Found C,
) 8.02 (4H, s, H-2,6), 7.92 (2H, s,
6
F
13
)
2
(C
6
H
3
-3,5-[C
6
F
13
]
2
)}
2
]
4 E. Perperi, Y. Huang, P. Angeli, G. Manos, C. R. Mathison, D. J.
Cole-Hamilton, D. J. Adams and E. G. Hope, Dalton Trans., 2004,
H
22
P
2
F
104Cl
2
2
062.
1
3
0.06. H, 0.60. H NMR (CDCl
3
5
L. P. Barthel-Rosa and J. A. Gladysz, Coord. Chem. Rev., 1999, 190–
1
9
1
H-4), 7.69 (8H, m, C ), 7.18 (8H, m, C
6
H
4
6
H
4
). F{ H} NMR
192, 587.
4
(
CDCl
a-CF
CF
16F, m, CF
3
) −80.96 (24F, m, CF
3
), −111.21 (8F, t, JFF = 14.2 Hz,
6 A. Aghmiz, C. Claver, A. M. Masdeu-Bult o´ , D. Maillard and D.
4
Sinou, J. Mol. Catal. A: Chem., 2004, 208, 97.
E. G. Hope, R. D. W. Kemmitt and A. M. Stuart, J. Chem. Soc.,
Dalton Trans., 1998, 3765.
B. Richter, E. de Wolf, G. van Koten and B.-J. Deelman, J. Org.
Chem., 2000, 65, 3885.
D. Sinou, D. Maillard, A. Aghmiz and A. M. Masdeu I-Bult o´ , Adv.
Synth. Catal., 2003, 345, 603.
2
), −111.45 (8F, t, JFF = 13.7 Hz, a-CF
2
), −121.42 (16F, m,
7
8
9
2
), −121.90 (16F, m, CF
2
), −122.75 (16F, m, CF
2
), −126.13
3
1
1
1
(
2
). P{ H} NMR (CDCl
3
) 21.7 (s, JPPt = 2743 Hz,
1
trans), 13.0 (s, JPPt = 3576 Hz, cis).
trans-[PtCl
Anal. Calc. for C44
9.69; H, 1.57. m/z (FAB) 1299 (M–Cl) . H NMR (CDCl
8H, s, H-2,6), 7.95 (4H, s, H-4), 7.72 (4H, m, PhH), 7.54 (6H,
2
{PPh(C
6
H
3
-3,5-[CF
3
]
2
)
2
}
2
]
1
0 (a) J. van den Broeke, B.-J. Deelman and G. van Koten, Tetrahedron
Lett., 2001, 42, 8085; (b) K. Ishihara, S. Kondo and H. Yamamoto,
Synlett, 2001, 1371; (c) G. J. Chen and C. Tamborski, J. Fluorine
Chem., 1989, 43, 207; (d) J. Duan, L. H. Zhang and W. R. Dolbier,
Jr., Synlett, 1999, 1245.
H
22
P
2
F
12Cl
2
Pt: C, 39.61; H, 1.65. Found C,
+
1
3
(
3
) 7.99
1
9
1
31
1
m, PhH). F{ H} NMR (CDCl
3
) −63.12 (s). P{ H} NMR
1
11 M. Cavazzini, A. Manfredi, F. Montanari, S. Quici and G. Pozzi,
(CDCl
3
) 23.0 (s, JPPt = 2739 Hz).
Eur. J. Org. Chem., 2001, 4639.
2 B. Croxtall, J. Fawcett, E. G. Hope and A. M. Stuart, J. Chem. Soc.,
Dalton Trans., 1999, 491.
3 J. A. S. Howell, N. Fey, J. D. Lovatt, P. C. Yates, P. McArdle, D.
Cunningham, E. Sadeh, H. E. Gottlieb, Z. Goldschmidt, M. B.
Hursthouse and M. E. Light, J. Chem. Soc., Dalton Trans., 1999,
3015.
1
1
cis- and trans-[PtCl
2
{P(C
6
H
4
-4-C
Pt: C, 32.92; H, 0.94. Found C,
) 8.00 (4H, s, H-2,6), 7.95 (2H, s,
6
F
13
)
2
(C
6
H
3
-3,5-[CF
3
]
2
)}
2
]
Anal. Calc. for C64
3
H-4), 7.69 (8H, m, C
H
22
P
2
F
64Cl
2
1
2.81. H, 1.00. H NMR (CDCl
3
1
9
1
6
H
4
), 7.18 (8H, m, C
6
H
4
). F{ H} NMR
3
8 6 6
D a l t o n T r a n s . , 2 0 0 5 , 3 8 6 2 – 3 8 6 7

View Article Online
1
1
4 W. Chen and J. Xiao, Tetrahedron Lett., 2000, 41, 3697.
5 J. Fawcett, E. G. Hope, R. D. W. Kemmitt, D. R. Paige, D. R. Russell
and A. M. Stuart, J. Chem. Soc., Dalton Trans., 1998, 3751.
6 E. G. Hope, R. D. W. Kemmitt, D. R. Paige, A. M. Stuart and
D. R. W. Wood, Polyhedron, 1999, 18, 2913.
17 See Rhodium catalysed hydroformylation, ed. P. N. W. M. Van
Leeuwen and C. Claver, Kluwer, Dordrecht, 2000, and refs. therein.
18 F. R. Hartley and C. A. McAuliffe, Inorg. Chem., 1979, 18, 1394.
19 E. G. Hope and J. Hopewell, unpublished work.
1
20 J. P. Farr, F. E. Wood and A. L. Balch, Inorg. Chem., 1983, 22, 3387.
D a l t o n T r a n s . , 2 0 0 5 , 3 8 6 2 – 3 8 6 7
3 8 6 7