Perfluoroalkylphosphine coordination chemistry of platinum: Synthesis of (C2F5)2PPh and (C2F 5)PPh2 complexes of platinum(II)

Article abstract of DOI:10.1039/b400995a

A 1: 1 addition of Ph₂PCl to an ethereal solution of C ₂F₅Li (formed from the reaction of BuLi with C ₂F₅C1) yields Ph₂P(C₂F₅) (abbreviated pfepp) (1). The introduction of a fluoroethyl group results in a phosphine with electronic characteristics that approximate phosphites, bridging the electronic gap between traditional donor phosphine ligands and more electrophilic phosphine ligands like PhP(C₂F₅)₂ (2). The pfepp ligand 1 is isolated as a high boiling liquid, which crystallizes upon standing at room temperature in an inert atmosphere. A series of Pt(u) complexes of the type trans-L₂PtCl₂ (L = pfepp 3; PhP(C₂F₅)₂ 4) have been prepared and structurally characterized by multinuclear NMR, IR and X-ray crystallography. The crystal structure of 1 is the first example of a structurally characterized monodentate phosphine with a pentafluoroethyl pendant group.

Full text of DOI:10.1039/b400995a

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Perfluoroalkylphosphine coordination chemistry of platinum:
synthesis of (C2F5)2PPh and (C2F5)PPh2 complexes of platinum(II)
Jason D. Palcic,a P. N. Kapoor,c Dean M. Roddickb and R. Gregory Peters*a
a Department of Chemistry, University of Memphis, Memphis, TN 38152, USA
b Department of Chemistry, University of Wyoming, Laramie, WY 82071, USA
c Department of Chemistry, University of Delhi, Delhi 110007, India
Received 31st January 2004, Accepted 23rd March 2004
First published as an Advance Article on the web 14th April 2004
A 1 : 1 addition of Ph2PCl to an ethereal solution of C2F5Li (formed from the reaction of BuLi with C2F5Cl) yields
Ph2P(C2F5) (abbreviated pfepp) (1). The introduction of a fluoroethyl group results in a phosphine with electronic
characteristics that approximate phosphites, bridging the electronic gap between traditional donor phosphine ligands
and more electrophilic phosphine ligands like PhP(C2F5)2 (2). The pfepp ligand 1 is isolated as a high boiling liquid,
which crystallizes upon standing at room temperature in an inert atmosphere. A series of Pt() complexes of the type
trans-L2PtCl2 (L = pfepp 3; PhP(C2F5)2 4) have been prepared and structurally characterized by multinuclear NMR,
IR and X-ray crystallography. The crystal structure of 1 is the first example of a structurally characterized
monodentate phosphine with a pentafluoroethyl pendant group.
Introduction
Results and discussion
Tertiary phosphines are among the most broadly utilized
ligands in transition metal chemistry. This is due in large part
to the ease in which the sterics and electronics of phosphines
are systematically manipulated by the careful selection of the
appropriate R substituent.1 While most efforts have been
focused on structure/reactivity relationships with electron
releasing substituents such as alkyl and aryl groups, the
development of phosphines bearing electron withdrawing sub-
stituents has not kept pace. This lack of development is likely
due to the comparative lack of methodologies for introducing
electron poor substituents as compared to traditional electron-
rich organic substituents. Despite this limitation, there has been
significant progress made in the development of phosphines
bearing electron-poor substituents.2–5
Addition of Ph2PCl to a pentafluoroethyllithium/ether solution
at –78 ЊC afforded Ph2P(C2F5) 1 in 89% isolated yield (eqn. (1)).
(1)
(C2F5)2P(Ph) 2 was prepared using a similar procedure and
its synthesis is reported elsewhere.4 Pentafluoroethyldiphenyl-
phosphine (abbreviated pfepp) 1, was fully characterized by
multinuclear NMR, IR and elemental analysis. The 31P NMR
of pfepp exhibits a triplet of quartets at Ϫ1.4 ppm, due to
coupling with the C2F5 substituent (2JPF = 58 Hz, 3JPF = 17 Hz).
The 19F NMR spectrum exhibits an A2M3 splitting pattern with
two resonances at Ϫ80.4 (CF3) and Ϫ112.6 ppm (CF2) (2JPF
=
The development of electron-poor phosphines bearing
fluorinated substituents has been the subject of several recent
studies.4,6,7 The unique combination of size and elec-
tronic influence allows fluorine to completely replace hydrogen
and impart significant electronic and steric changes to organic
molecules.8–11 The use of fluorinated organic substituents
instead of traditional hydrocarbon substituents has a pro-
found influence specifically on trivalent phosphorus ligands,
producing strong π-acceptor phosphines with greater steric
influence and resistance to degradation via traditional decom-
position pathways. Recently there has been considerable inter-
est in the introduction of perfluorocarbon tails to phosphine
ancillary ligands in order to solubilize metal complexes in
fluorinated solvents, and their application towards biphasic
catalysis.12,13 However, these systems incorporate hydrocarbon
spacer groups that effectively insulate the metal from the
electronic influence of the fluorine-bearing substituents.
While the synthesis of CF3-substituted phosphine ligands is
non-trivial due to the relative inaccessibility of the trifluoro-
methyl anion,14–19 C2F5-substituted phosphines are more
conveniently prepared from pentafluoroethyllithium4,7,20 and
pentfluorophenyl-substituted phosphines are well-known.
Recently phosphine ligands bearing perfluorovinyl substituents
have also been reported.6,21–24 In this paper we report the
synthesis of a new perfluoroethylphosphine, Ph2P(C2F5) and
present some initial coordination studies with square-planar
platinum(). A structural comparison with the bis(perfluoro-
ethyl)phenylphosphine PhP(C2F5)2 platinum analog is also
presented.
3
3
57.0, JPF = 16.5 Hz, JFF = 3.1 Hz). This is in contrast to 2,
whose 3JPF and 3JFF coupling constants are essentially zero.4
Ph2P(C2F5) was isolated as a high-boiling colorless liquid.
However, upon prolonged standing under a helium atmosphere
at room temperature, 1 slowly crystallized. The structure of 1
was confirmed by single crystal X-ray diffraction and is shown
in Fig. 1. To our knowledge, this is the first example of a struc-
turally characterized monodentate phosphine with a penta-
Fig. 1 ORTEP drawing of Ph2P(C2F5), thermal ellipsoids are shown at
the 30% probability level and hydrogen atoms are omitted for clarity.
D a l t o n T r a n s . , 2 0 0 4 , 1 6 4 4 – 1 6 4 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 4
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Table 1 Crystal data and structure refinement for Ph2P(C2F5), trans-[Ph2P(C2F5)]2PtCl2 and trans-[PhP(C2F5)2]2PtCl2
Ph2P(C2F5)
trans-[PPh2(C2F5)]2PtCl2
trans-[PPh (C2F5)2]2PtCl2
Empirical formula
Formula weight
C14H10F5P
304.19
C28H20Cl2F10P2Pt
874.37
C20H10Cl2F20P2Pt
958.21
Crystal system
Space group
Orthorhombic
Pbca
Triclinic
P1
Monoclinic
P21/n
¯
Unit cell dimensions:
a/Å
b/Å
c/Å
α/Њ
β/Њ
28.918(4)
11.559(2)
7.9717(12)
8.0451(13)
10.2057(12)
10.9332(15)
111.426(8)
106.208(12)
102.847(11)
747.75(18)
1
10.1326(9)
12.010(2)
11.5424(11)
100.911(6)
γ/Њ
V/Å3
2664.5(7)
8
1.517
1379.2(3)
2
2.307
5.546
Z
Dc/g cmϪ3
1.942
5.059
µ/mmϪ1
0.251
F(000)
1232
420
904
Crystal size/mm
θ Range for data collection/Њ
Reflections collected
0.6 × 0.5 × 0.4
2.26–25.00
3069
0.30 × 0.40 × 0.50
8.51–24.99
1290
0.40 × 0.26 × 0.24
2.46–25.00
3152
Independent reflections (Rint
Max., min. transmission
T /K
)
2323 (0.0226)
1290 (0.0000)
0.5710, 0.4220
293(2)
1290/0/196
R1 = 0.0207, wR2 = 0.0528
R1 = 0.0208, wR2 = 0.0528
0.448, Ϫ0.553
2418 (0.0504)
0.9796, 0.2641
173(2)
173(2)
2323/0/181
R1 = 0.0402, wR2 = 0.1023
R1 = 0.0525, wR2 = 0.1095
0.308, Ϫ0.246
Data/restraints/parameters
Final R indices [I > 2σ(I )]a
R Indices (all data)
2417/0/205
R1 = 0.0386, wR2 = 0.1058
R1 = 0.0413, wR2 = 0.1098
1.945, Ϫ2.918
Largest diff. peak and hole/e ÅϪ3
a R1 = Σ(|Fo| Ϫ Fc|)/Σ|Fo|.
Table 2 Selected bond length (Å) and angle (Њ) data for Ph2P(C2F5)
Table 3 Comparison of chemical shift and 1JPtP data for trans-L2PtCl2
complexes
P(1)–C(21)
P(1)–C(11)
P(1)–C(1)
F(1)–C(1)
1.832(3)
1.835(3)
1.891(3)
1.366(3)
F(5)–C(2)
F(3)–C(2)
C(1)–C(2)
1.324(3)
1.335(3)
1.526(4)
Ligand (L)
δ(31P)/ppm
1JP–Pt/Hz
Ref.
pfepp 3
dfpp 4
31.5
18.5
21.0
19.8
28.4
29.1
74.9
2945
4120
2794
2637
2482
2531
4405
This work
This work
22
29
30
30
31
C(21)–P(1)–C(11)
C(21)–P(1)–C(1)
104.88(11)
100.26(11)
C(11)–P(1)–C(1)
C(2)–C(1)–P(1)
99.04(11)
115.0(2)
PPh2(CCl᎐CF2)
᎐
PPh3
PPhEt2
n
PPh2 Bu
fluoroethyl pendant group. Crystal data collection, solution and
refinement data for Ph2P(C2F5) are given in Table 1 while rele-
vant bond length and angle data are summarized in Table 2.
The P–arene bond distance of 1.835(3) Å in 1 is similar to that
P(o-OC6H4Me)3
reported for PhP(CF᎐CF ) (1.830 Å).6 The geometry about the
᎐
2
2
phosphorus atom is nearly identical, with the C(Ar)–P–Rf bond
angle in each compound of ∼100Њ (99.04 and 100.26Њ for pfepp
and 100.26Њ for PhP(CF᎐CF ) ). The C–F bond distances on
᎐
2
2
the CF2 group are slightly longer on average than the C–F
bonds on the CF3 group (1.366 vs. 1.330 Å average), in accord
with earlier reports.4,7
Treatment of (cod)PtCl2 with a slight excess of 1 in refluxing
toluene overnight results in the formation of a yellow solid,
trans-[Ph2P(C2F5)]2PtCl2 3 (eqn. (2)). The 31P NMR of this
complex shows a downfield shift of ∼30 ppm relative to the
original ligand resonance and associated 195Pt satellites (I = ½,
33% abundant, 1JPtP = 2945 Hz).
Fig. 2 ORTEP drawing of trans-[Ph2P(C2F5)]2PtCl2, thermal ellipsoids
are shown at the 30% probability level and hydrogen atoms are omitted
for clarity.
(2)
Selected bond distances and angles are given in Table 4. The
P–Pt–Cl bond angle is 97.01Њ. The Pt–P and Pt–Cl bond dis-
tances of 2.2961 and 2.3070 Å, respectively, are consistent with
other trans-PtL2Cl2 complexes (L = phosphine).5,22,25
The analogous displacement of cod from (cod)PtCl2 by
(C2F5)2P(Ph) 2 (abbreviated dfpp) does not take place. How-
ever, treatment of (PhCN)2PtCl2 with dfpp in toluene yielded
trans-(dfpp)2PtCl2 4. 31P NMR spectra of 4 redissolved in ben-
zene show a major resonance at 18.5 ppm (1JPPt = 4120 Hz) as
well as a minor (∼10%) resonance at 15.8 ppm with a very large
The magnitude of the phosphorus coupling to platinum is
consistent with the formation of a trans species, and is some-
what larger than analogous complexes bearing electron-
releasing phosphines (Table 3).
Recrystallization of the complex from a diethyl ether–
petroleum ether mixture yielded crystals suitable for X-ray dif-
fractions studies. The ORTEP representation of 3 is shown in
Fig. 2 and confirms the trans geometry about the metal center.
D a l t o n T r a n s . , 2 0 0 4 , 1 6 4 4 – 1 6 4 7
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Table 4 Selected bond length (Å) and angle (Њ) data for trans-
[Ph2P(C2F5)]2PtCl2
Table 5 Selected bond length (Å) and angle (Њ) data for trans-
[PhP(C2F5)2]2PtCl2
Pt(1)–P(1)
Pt(1)–Cl(1)
P(1)–C(11)
P(1)–C(21)
P(1)–C(1)
2.2961(13)
2.3070(12)
1.812(6)
1.813(5)
1.917(5)
C(1)–F(1)
C(1)–C(2)
C(2)–F(5)
C(2)–F(3)
C(2)–F(4)
1.368(7)
1.517(12)
1.292(13)
1.321(9)
1.338(12)
Pt(1)–P(1)
Pt(1)–Cl(1)
P(1)–C(5)
P(1)–C(3)
P(1)–C(1)
C(1)–F(2)
2.2916(12)
2.3002(12)
1.801(5)
1.897(6)
1.915(7)
1.353(9)
C(1)–C(2)
C(2)–F(4)
C(3)–F(6)
C(3)–C(4)
C(4)–F(8)
1.531(11)
1.323(10)
1.357(7)
1.533(10)
1.318(7)
P(1)–Pt(1)–Cl(1)
C(11)–P(1)–C(21) 111.2(3)
C(11)–P(1)–C(1) 99.6(2)
97.01(5)
C(11)–P(1)–Pt(1) 109.89(19)
C(21)–P(1)–Pt(1) 116.25(18)
P(1)–Pt(1)–Cl(1)
C(5)–P(1)–C(3)
C(5)–P(1)–C(1)
C(3)–P(1)–C(1)
C(5)–P(1)–Pt(1)
84.77(5)
99.8(2)
104.0(3)
102.5(3)
119.5(2)
C(3)–P(1)–Pt(1)
C(1)–P(1)–Pt(1)
F(2)–C(1)–F(1)
C(2)–C(1)–P(1)
118.2(2)
110.7(2)
108.3(6)
116.4(5)
C(1)–P(1)–Pt(1)
118.52(19)
platinum coupling (1JPPt = 4700 Hz) that is consistent with its
formulation20 as the chloride-bridged dimer, [(dfpp)2Pt(Cl)-
(µ-Cl)]2 5 (eqn. (3)) and demonstrates one significant difference
between the (pfepp)2Pt and (dfpp)2Pt moieties. The formation
of bridged dimers in trans-[PR3]2PtX2 systems depends upon
both the relative donor ability of the phosphine ligand and the
coordination/bridging ability of the anionic ligand X. Ligand
loss is followed by dimerization for trans-[MeP(C2F5)2]2-
Pt(CH3)(O2CCF3), though similar dimerization is not observed
when the trifluoroacetate group is replaced by a more weakly
coordinating anion such as triflate or fluorosulfonate.20 The
lowered basicity of PhP(C2F5)2 relative to MeP(C2F5)2 and the
more strongly coordinating Cl (relative to trifluoroacetate)
combine to promote the formation of the chloride bridged
dimer [(dfpp)2Pt(Cl)(µ-Cl)]2 5. However, due to the increased
basicity of the phosphine, similar bridging systems involving
trans-[Ph2P(C2F5)]2PtCl2 3 were not observed. Metal–halogen
complexes are often used as precursors in the preparation of
metal–alkyl compounds; however, attempts to alkylate 3 or 4 to
generate L2Pt(R)Cl or L2PtR2 products (L = dfpp or pfepp)
with Grignard, alkyllithium, tin or zinc reagents did not lead to
isolable products.
ively), despite the change in phosphine basicity. Furthermore,
these distances are also similar to the PPh3 analog,25 indicating
that bond length data is relatively insensitive to changes in the
electronic environment of the ligand for this class of com-
pounds. The P–Pt–Cl bond angle of 4 is 95.23Њ; falling between
the P–Pt–Cl bond angles of 3 (97.01Њ) and trans-[(PPh3)2PtCl2],
with a bond angle of 92.12Њ.
In summary, the high-yield synthesis of pentafluoroethyl-
diphenylphosphine, pfepp, is reported. This ligand bridges the
electronic gap between traditional electron rich ligands such as
PPh3 and electron poor ligands such as dipentafluoroethyl-
phenylphosphine, dfpp. Thermolysis of pfepp in toluene solu-
tions of (cod)PtCl2 yielded the corresponding trans-L2PtCl2
complex (pfepp)2PtCl2 3. However, similar treatment of
(cod)PtCl2 with dfpp did not produce the analogous com-
pound; the lowered donating ability of dfpp required a more
labile starting material. Treatment of (PhCN)2PtCl2 with dfpp
yielded the expected trans dichloro product, (dfpp)2PtCl2 4. An
X-ray crystal structure comparison between (dfpp)2PtCl2,
(pfepp)2PtCl2 and the PPh3 analog indicated that the metrical
parameters of these complexes are relatively insensitive to the
electronic environment of the ligand. Despite the similarities in
this X-ray data, the reactivity of these complexes is affected by
the electronic characteristics of the phosphine ligand. While the
(pfepp)2PtCl2 complex was stable in solution and demonstrated
no tendency toward dimerization, the lowered basicity of the
phosphine in the (dfpp)2PtCl2 analog resulted in the formation
of a minor amount of the halide-bridged dimeric product
[(dfpp)2Pt(Cl)(µ-Cl)]2 5.
(3)
Crystallization from a 1 : 1 mixture of benzene and hexane
yielded crystals of 4 suitable for X-ray analysis. Redissolving
these crystals again produced a 9 : 1 mixture of 4 and 5 as well
as a small amount of free phosphine. The ORTEP drawing of 4
is shown in Fig. 3 and a list of relevant metrical data is summar-
ized in Table 5. The molecular geometry of 4 is similar to that
of 3. A structural comparison of 3 and 4 indicates that the Pt–P
and Pt–Cl bonds of 4 (Pt–P 2.2916 Å and Pt–Cl 2.3002 Å) are
essentially identical to those in 3 (2.2961 and 2.3070 Å, respect-
Experimental
General considerations
All manipulations were conducted under an inert atmosphere
using glove box, high-vacuum and/or Schlenk techniques.
Water and oxygen free solvents were prepared from sodium/
benzophenone and vacuum distilled prior to use. Chloro-
diphenylphosphine, n-butyllithium (2.5 M in hexanes) and
cyclooctadiene were obtained from Aldrich (Milwaukee, WI)
and used without further purification. C2F5Cl was obtained
from PCR and used without further purification. H, 19F and
1
31P NMR spectra were measured using a JEOL 270 MHz
spectrometer operating at 270.17, 254.21 and 109.37 MHz,
respectively. 31P and 19F NMR spectra were referenced to
H3PO4 and CFCl3, respectively, with downfield shifts taken to
be positive. Infrared spectra were obtained on a Perkin-Elmer
FTIR instrument as Nujol mulls (unless otherwise noted).
Elemental analyses were obtained from Desert Analytics.
27
(cod)PtCl2,26 PPh(C2F5)2,4 and (PhCN)2PtCl2 were prepared
according to established literature procedures.
PPh2(C2F5)
Fig. 3 ORTEP drawing of trans-[PhP(C2F5)2]2PtCl2, thermal ellipsoids
are shown at the 30% probability level and hydrogen atoms are omitted
for clarity.
CAUTION: Poor temperature control during the synthesis
of C2F5Li can result in uncontrolled decomposition and is
D a l t o n T r a n s . , 2 0 0 4 , 1 6 4 4 – 1 6 4 7
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potentially dangerous. We recommend that solutions of C2F5Li
be maintained between Ϫ90 and Ϫ70 ЊC.
tals of 4 were obtained from a 1 : 1 mixture of benzene–hexane.
Single-crystal X-ray data for 1, 3 and 4 were collected on a
Siemens P4 diffractometer equipped with a molybdenum tube
(λ = 0.71073 Å) and a graphite monochromator. Empirical
absorption corrections based on psi-scans were applied, and the
structures were solved by direct methods and refined by full-
matrix least-squares techniques on F 2 using structure solution
programs from the SHELXTL system.28 All nonhydrogen
atoms were refined anisotropically, while hydrogen atoms were
placed in calculated positions and refined with fixed isotropic
thermal parameters.
To a 300 mL, two-neck flask under N2 fitted with a manifold
adaptor and a rubber septum was added 40 mL n-BuLi (2.5 M
in hexanes, 100 mmol). The hexanes were removed under
vacuum and 125 mL of diethyl ether was transferred to the
reaction flask. This solution was kept under vacuum while
9.9 mL of C2F5Cl (bp –34 ЊC, density 1.88 g mLϪ1, 120 mmol)
was slowly transferred into the reaction solution in order to
maintain a reaction solution temperature below Ϫ78 ЊC. Once
the transfer was complete, the reaction solution was allowed to
stir for an additional 30 min. At this point an 18.0 mL aliquot
of Ph2P–Cl (density = 1.22 g mLϪ1; 100 mmol) was slowly
added (15 min) to the reaction solution under a nitrogen
counterflow while maintaining a reaction temperature of
Ϫ78 ЊC. After the addition was complete, the solution was
stirred at Ϫ78 ЊC for an additional 15 min and then allowed to
slowly warm to room temperature. Atmospheric N2 distillation
removed the volatile components (BuCl, diethyl ether). The
pressure was reduced to 2 Torr, and the product (27.01 g, 89%
yield) was collected between 104 and 107 ЊC. Anal. Calc. for
CCDC reference numbers 229924–229926.
See http://www.rsc.org/suppdata/dt/b4/b400995a/ for crystal-
lographic data in CIF or other electronic format.
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2
3
δ Ϫ1.41 (tq, JPF = 58 Hz, 2F; JPF = 17 Hz, 3F). 19F NMR
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2
3
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trans-[PPh2(C2F5)]2PtCl2
To a solution of 0.748 g (2.0 mmol) of (cod)PtCl2 and 25 mL
of toluene was added 1.244 g (4.1 mmol) of PPh2(C2F5). This
solution was refluxed for 20 h, and toluene was removed via
vacuum, leaving a yellow powder. The residue was slurried in
approximately 25 mL of petroleum ether (bp 38–54 ЊC) and
filtered, yielding 0.701 g of product (80%). Recrystallization
was performed by dissolving 56 mg of crude product in 50 mL
of diethyl ether, decanting the liquid from undissolved crude
product and adding 25 mL of petroleum ether (bp 38–54 ЊC)
and allowing slow evaporation for 24 h at room temperature.
Anal. Calc. for C28H20Cl2F10P2Pt: C, 38.46; H, 2.31. Found: C,
38.22; H, 2.36%. 1H NMR (C6D6): δ 8.04 (m), 6.97 (m). 31P{1H}
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NMR (C6D6): δ 31.5 (m, JPPt = 2945 Hz). 19F NMR (C6D6):
1
δ Ϫ75.5 (s, CF3); Ϫ102.8 (m, CF2). IR (Nujol, KCl, cmϪ1): 1586,
1298, 1200, 1128, 1087, 957, 738, 719, 685, 627.
18 T. Billard, B. R. Langlois and G. Blond, Tetrahedron Lett., 2000, 41,
8777.
trans-[PPh(C2F5)2]2PtCl2
19 R. P. Singh and J. M. Shreeve, Tetrahedron, 2000, 56, 7613.
20 J. L. Butikofer, J. M. Hoerter, R. G. Peters and D. M. Roddick,
Organometallics, 2004, 23, 400.
21 K. K. Banger, A. K. Brisdon and A. Gupta, Chem. Commun., 1997,
139.
22 N. A. Barnes, A. K. Brisdon, M. J. Ellis and R. G. Pritchard,
J. Fluorine Chem., 2001, 112, 35.
23 A. K. Brisdon and K. K. Banger, J. Fluorine Chem., 1999, 100, 35.
24 R. G. Peters, J. D. Palcic and R. G. Baughman, Acta Crystallogr.,
Sect. E, 2003, E59, m1198.
25 M. H. Johansson and S. Otto, Acta Crystallogr., Sect. C, 2000, 56,
e12.
26 J. X. McDermott, J. F. White and G. M. Whitesides, J. Am. Chem.
Soc., 1976, 98, 6521.
A flask was charged with 200 mg (0.424 mmol) of (PhCN)2-
PtCl2, 0.20 mL (1.2 mmol) dfepp, and 15 mL toluene. Initially
yellow, the solution became light brown after stirring for 18 h at
ambient temperature. Evaporation of the solution to ca. 0.5 mL
and addition of 10 mL petroleum ether yielded after filtration
and drying under vacuum a light gray solid (0.311 g, 82%).
Anal. Calc. for C20H10Cl2F20P2Pt: C, 25.07; H, 1.05. Found: C,
25.82; H, 0.97%. 1H NMR (C6D6): δ 8.11 (dd, 3JHH = 12, 6 Hz,
3
4H; meta-C6H5), 6.88 (d, JHH = 6 Hz, 4H; ortho-C6H5) 6.27
(d, 3JHH = 12 Hz, 2H; para-C6H5). 31P{1H} NMR (C6D6): δ 18.5
(p, 2JPF = 56 Hz, 1JPPt = 4120 Hz).
27 G. K. Anderson and M. Lin, Inorg. Synth., 1990, 28, 60.
28 G. M. Sheldrick, SHELXTL Crystallographic System, Version 5.03/
Iris, Siemens Analytical X-ray Instruments, Madison, WI, 1994.
29 L. Bemi, H. C. Clark, J. A. Davies, C. A. Fyfe and R. E. Wasylishen,
J. Am. Chem. Soc., 1982, 104, 438.
30 S. O. Grim, R. Keiter and W. McFarlane, Inorg. Chem., 1967, 6,
1133.
X-Ray diffraction studies
The crystallographic data for compounds 1, 3 and 4 are sum-
marized in Table 1. Compound 1 was isolated in pure form as a
high boiling liquid; this liquid became crystalline during stor-
age in a helium-filled glovebox. Crystals of 3 were obtained
from a mixture of diethyl ether and petroleum ether while crys-
31 N. Ahmad, E. W. Ainscough, T. A. James and S. D. Robinson,
J. Chem. Soc., Dalton Trans., 1973, 11, 1148.
D a l t o n T r a n s . , 2 0 0 4 , 1 6 4 4 – 1 6 4 7
1647