Water soluble platinum(II) and palladium(II) complexes of alkyl sulfonated phosphines

Article abstract of DOI:10.1016/S0020-1693(99)00140-1

The reactions of the alkylsulfonated phosphines LM=Ph₂P(CH₂)_nSO₃Na/K (n=2, 3, 4) with K₂PtCl₄ and K₂PdCl₄ have been studied in homogeneous aqueous solution as a function of pH. In homogeneous acidic solution the protonated phosphines react to give cis- and trans-PtCl₂(LH)₂. The biphasic reaction between 1,5-cyclooctadiene platinum(II) chloride in dichloromethane and acidified aqueous LNa/K gives a higher proportion of the cis isomer. In neutral solution the initial reaction to give [PtCl(LNa/K)₃]⁺Cl^- is followed by slow formation of cis-PtCl₂(LNa/K)₂. K₂PdCl₄ reacts more rapidly to give PdCl₂(LNa/K)₂. In homogeneous alkaline solution rapid oxidation of the phosphine occurs with only small amounts of platinum complex being observable. The biphasic reaction yields phosphine oxide in the aqueous layer and a small amount of the chelate complexes PtL₂ in the organic. Representative complexes have been isolated and characterised and the mechanisms for the reactions discussed. The electrospray mass spectra of solutions of the isolated complexes have been recorded in both positive and negative ionisation modes. The positive ionisation spectra are complicated, but platinum and palladium containing ions derived from loss of chloride, H⁺ and HCl are observed in the negative ionisation spectra.

Full text of DOI:10.1016/S0020-1693(99)00140-1

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 290 (1999) 189–196
Water soluble platinum(II) and palladium(II) complexes of
alkyl sulfonated phosphines
Janet L. Wedgwood a, Ann P. Hunter b, Roman A. Kresinski a, Andrew W.G. Platt a,*,
Bridget K. Stein b
a Chemistry Di6ision, Staffordshire Uni6ersity, College Road, Stoke-on-Trent ST4 2DE, UK
b EPSRC National Mass Spectrometry Ser6ice Centre, Chemistry Department, Uni6ersity of Wales, Swansea, Singleton Park,
Swansea SA2 8PP, UK
Received 27 November 1998; accepted 17 February 1999
Abstract
The reactions of the alkylsulfonated phosphines LM=Ph2P(CH2)nSO3Na/K (n=2, 3, 4) with K2PtCl4 and K2PdCl4 have been
studied in homogeneous aqueous solution as a function of pH. In homogeneous acidic solution the protonated phosphines react
to give cis- and trans-PtCl2(LH)2. The biphasic reaction between 1,5-cyclooctadiene platinum(II) chloride in dichloromethane and
acidified aqueous LNa/K gives a higher proportion of the cis isomer. In neutral solution the initial reaction to give
[PtCl(LNa/K)3]+Cl− is followed by slow formation of cis-PtCl2(LNa/K)2. K2PdCl4 reacts more rapidly to give PdCl2(LNa/K)2.
In homogeneous alkaline solution rapid oxidation of the phosphine occurs with only small amounts of platinum complex being
observable. The biphasic reaction yields phosphine oxide in the aqueous layer and a small amount of the chelate complexes PtL2
in the organic. Representative complexes have been isolated and characterised and the mechanisms for the reactions discussed.
The electrospray mass spectra of solutions of the isolated complexes have been recorded in both positive and negative ionisation
modes. The positive ionisation spectra are complicated, but platinum and palladium containing ions derived from loss of chloride,
H+ and HCl are observed in the negative ionisation spectra. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Platinum complexes; Palladium complexes; Water soluble complexes; Alkyl sulfonated phosphine complexes
1. Introduction
trial application [5]. While alkyl substituted phosphines
Ph2P(CH2)nSO3Li/Na/K (n=2, 3, 4) have been re-
ported [6,7], there are relatively few studies on their
transition metal complexes [7].
Interest in water soluble phosphines stems mainly
from the potential application of their transition metal
complexes to catalysis in aqueous systems. Phosphines
bearing various polar functionalities such as hydroxy-
alkyl [1] and polyethers [2] or ionic groups such as alkyl
ammonium [3] have previously been synthesised and
their complexes shown to have enhanced water solubil-
ity. The earliest examples of water soluble phosphines
were the sulfonated triphenylphosphines, and these and
other aryl sulfonated derivatives have received consid-
erable attention [4] and have subsequently found indus-
2. Results and discussion
2.1. Ligand synthesis
The phosphines Ph2P(CH2)nSO3Na/K were prepared
by reactions of alkali metal diphenylphosphides with
bromoethane sulfonic acid sodium salt (n=2) [6] or
propane and butane sultone (n=3, 4) in THF solution
[7]. Interestingly, we have not found it possible to
* Corresponding author. Tel.: +44-1782-294 784; fax: +44-1782-
745 506.
prepare
Ph2P(CH2)2SO3Li
from
LiPPh2
and
E-mail address: a.platt@staffs.ac.uk (A.W.G. Platt)
Br(CH2)2SO3Na. Similarly, there was no reaction be-
0020-1693/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(99)00140-1

190
J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
2.2. Coordination chemistry studies
2.2.1. Acidic solution
The phosphines are readily protonated in aqueous
1
HCl as seen by the large JPH coupling and a downfield
shift in the 31P NMR signal. Such solutions react with
aqueous K2PtCl4 to give cis-PtCl2(LH)2 (1). The 31P
NMR data are collected in Table 1. For L−
=
Ph2P(CH2)2SO3− both cis- and trans-isomers are ob-
1
servable by 31P NMR, with JPPt values being typical of
a coordinated phosphine trans to chloride and phos-
phine, respectively. The trans-isomer 2 is considerably
less soluble than 1, and precipitates from solution as
trans-PtCl2(Ph2P(CH2)2SO3H)2. The proportion of 1
can be increased by reacting a dichloromethane solu-
tion of CODPtCl2 with the phosphine in HCl. The
reaction is much faster and yields a precipitate of 2 with
1 in aqueous solution. Slow evaporation of the aqueous
solutions affords solid materials of composition
PtCl2(PPh2(CH2)2SO3H)2 · 3.5H2O. In aqueous solution
1 is more strongly acidic than 2 and potentiometric
titrations of each with sodium hydroxide show two
endpoints corresponding to the neutralisation of the
two sulfonic acid groups. The relative acidities of the
isomers may be rationalised in terms of intramolecular
hydrogen bonding in the mono deprotonated anion
being favoured by the cis-orientation of the sulfonate
groups. IR spectra show, in addition to the expected
OH bands at 3420 and 1630 cm−1, two S–O stretches
at 1180 and 1210 cm−1, respectively. The relative sim-
plicity of the spectrum in this region is consistent with
local C36 symmetry, implying that the sulfonate group
is present as –SO3− and is not coordinated to the
metal.
Scheme 1. The reaction of diphenylphosphine with propane sultone.
tween BrCH2SO3Na and either sodium or potassium
diphenylphosphide even on prolonged reflux in THF,
and we have been unable to prepare Ph2PCH2SO3Na/
K. We attribute this lack of reactivity to unfavourable
electrostatic and steric interactions between the
diphenylphosphide anion and the sulfonate group
which is close to the site of substitution. Also, attempts
to prepare the free acid, Ph2P(CH2)3SO3H, by 1:1 reac-
tion of diphenylphosphine with propane sultone in
THF gave mainly the zwitterionic phosphonium salt
and unreacted diphenylphosphine, as shown in Scheme
1. The initially formed phosphine, which is observable
in small amounts in the reaction mixture, reacts with
excess sultone in preference to the less basic Ph2PH.
Table 1
31P NMR data for the phosphines and their platinum complexes
Ph2P(CH2)nSO3M
a
b
n
l
1JPH
l
2
3
4
6.7
7.1
7.7
494
483
501
−18.2
−18.2
−17.8
a
b
PtCl2(LH)2
PtCl2(LM)2
[PtCl(LM)3]Clb
n
l
1JPPt
l
1JPPt
lx
1JPPt
2405
2395
2386
ly
1JPPt
2JPP
19
(1a)
(2a)
(1b)
(2b)
(1c)
(2c)
2
3
4
5.5
13.6
7.1
3735
3059
3715
(3a)
(3b)
(3c)
(3d)
(3e)
(3f)
4.6
17.6
6.6
12.5
6.4
2496
3704
2985
3698
2483
3696
(5a) 13.6(d)
(5b) 15.9(d)
(5c) 15.6(d)
3.2(t)
4.4(t)
3.8(t)
not observed
3638
19
6.9
3726
12.5
3639
19
a In 30% aqueous HCl.
b In water lx P trans to P, ly P trans to Cl.

J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
191
2.2.2. Neutral solution
the substitution of the final chloride by the phosphine.
Thus, on reaction of K2PtCl4 with 10 equiv. of
Ph2P(CH2)3SO3Na in aqueous solution only the 1:3
adduct is observed in the 31P NMR spectrum, in addi-
tion to excess phosphine.
When the reaction is carried out with a 1:3 ratio of
Pt:LNa/K the complex [PtCl(LNa/K)3]+Cl− (5a–c) is
the only product and can be isolated on reducing the
solvent volume.
The corresponding reactions with K2PdCl4 are rapid,
and only the final product is observable by 31P NMR
spectroscopy. The NMR data are given in Table 2. The
solutions are stable over several weeks (31P NMR evi-
dence), and on standing give the palladium complexes
PdCl2(LNa/K)2 · xH2O (4a–c), (see Section 3). The re-
action with the butylsulfonated phosphine gives two
products. A red solid, which is formed in small
In neutral solution the reactions follow a different
path. The 31P NMR spectrum of the reaction when
K2PtCl4 is added to 2 equiv. of LM shows the initial
formation of [PtCl(LNa/K)3]+Cl− (5), which exhibits a
characteristic doublet and triplet both with 195Pt satel-
lites (Table 1). When LM=Ph2P(CH2)2SO3Na the 3:1
adduct rapidly converts to cis-PtCl2(LNa/K)2 (3a), and
the 195Pt satellites are not observed for the lower inten-
sity triplet signal. For the propyl and butylsulfonated
phosphines the reaction of 5b and 5c is much slower.
Over a period of a week a reaction occurs to give the
expected products 3c and 3e. Small amounts of the
trans-isomers 3b, 3d and 3f are also observed in solu-
tion during this reaction but are not present in the final
solutions. Interestingly, the same products are observed
in the reverse addition reaction when LNa/K is slowly
added to K2PtCl4. Thus, it appears that the initial
substitution into PtCl42− probably proceeds via the
formation of trans-PtCl2(LNa/K)2. This reacts rapidly
with further phosphine to give the kinetically preferred
3:1 complex regardless of the ratio of metal to phos-
phine present in the reaction mixture. The chloride/
phosphine substitution pattern implied by these
observations is shown in Scheme 2 and is consistent
with the expected trans-effects of the ligands. To the
best of our knowledge this is the first observation of
chloride/phosphine substitution reactions in aqueous
solution. Interestingly, we have found no evidence for
amounts, analyses as
a bridged chloride dimer
(KL)ClPd(m2Cl2)PdCl(LK) · 4H2O, while the yellow 4c
precipitates more slowly. Both materials are highly
soluble in water and as a result were obtained in very
small amounts.
The complexes prepared from reaction between
Ph2P(CH2)3SO3Na and K2PtCl4 or K2PdCl4 are isolated
as mixed sodium/potassium salts. This was confirmed
by elemental analysis and the positive ionisation elec-
trospray mass spectra, which clearly indicate the pres-
ence of both sodium and potassium containing ions
when the isolated solids are redissolved in water. The
31P NMR spectra of the complexes are independent of
the counter ion. The IR spectra of all the complexes
show the presence of water and sulfonate groups unco-
ordinated to the metal.
The isolated complexes are sufficiently soluble in
water for NMR studies, but less soluble in other com-
mon organic solvents. Despite repeated attempts we
have been unable to grow crystals of any of the com-
plexes which are suitable for single crystal X-ray dif-
fraction studies. While crystalline materials were
obtained in some cases, they were prone to such rapid
loss of solvent, with concomitant loss of crystallinity,
that diffraction analysis could not be undertaken.
2.2.3. Alkaline solution
The addition of aqueous K2PtCl4 to an alkaline
solution (pH\12) of LNa/K, under a nitrogen atmo-
sphere, gave a phosphine oxide almost quantitatively
(31P NMR evidence). One possible reason for this ob-
servation is oxygen transfer from S to P, which is
shown in Scheme 3. Several factors make this mecha-
nism seem attractive. The higher bond enthalpy of the
PꢀO bond compared [8] with SꢀO would make the
reaction thermodynamically favourable and, indeed, a
similar S to P oxygen migration has been reported in
Scheme 2. The Cl/P substitution pattern for PtCl42−
.
Table 2
31P NMR data for PdCl2(Ph2P(CH2)nSO3M)2 in water
n
l
(4a)
(4b)
(4c)
2
3
4
28.4
30.1
29.8
the
isomerisation
of
Ph2PCH2S(O)Me
to
Ph2P(O)CH2SMe [9]. Also, the formal oxidative addi-

192
J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
K2PtCl4 in alkaline solution under nitrogen is identical
to that of Ph2P(O)(CH2)3SO3Na prepared by H2O2
oxidation of the phosphine. Similarly, the IR spectra of
the isolated oxide shows no significant differences in the
SO stretching region.
A more plausible cause of oxidation of the phosphine
functionality involves oxidation by Pt(II), and a similar
redox reaction between sulfonated triphenylphosphine
and Rh(III) in water giving Rh(I) complexes and the
phosphine oxide has been described [13]. While the
reduction potentials of the species involved are not
available, those for the appropriate oxidation states in
alkaline solution of Pt(OH)2/Pt E°=0.16 V and PO43−
/
HPO32− E°= −1.05 V [10] indicate that such a reac-
tion would be favourable, and indeed the synthesis of
low valent platinum species such as Pt(Ph3P)4 is
achieved by reduction of Pt(II) in alkaline media [14].
We have, however, found no evidence of stable plat-
inum(0), or other phosphine complexes in these reac-
tions and 195Pt NMR spectra of the reaction mixture
for LM=Ph2P(CH2)3SO3Na show three unassigned
singlets at 830, 442 and 133 ppm relative to K2PtCl6.
These shifts are within the range for Pt(II), but are not
consistent with Pt(0) which typically has shifts in the
−4000 to −6000 ppm range [15]. The recently re-
ported insertion of oxygen from water into a metal
phosphorus bond [16] to give phosphine oxides seems
unlikely to be occurring in our systems as dissolution of
the preformed complexes in aqueous alkali does not
give the phosphine oxide but rather Pt(OH)2(LNa/K)2
(NMR evidence) which appear indefinitely stable in
solution.
Scheme 3. A possible mechanism for sulfur to phosphorus oxygen
transfer.
tion involved in the first step might be expected to be
more favourable in alkaline solution in view of the
Pt(IV)/Pt(II) reduction potentials; PtCl62−/PtCl42−
E°=0.74 V at pH 0, compared with Pt(OH)62−
/
Pt(OH)2 E°=0.2 V [10] at pH 14. In addition, com-
plexes analogous to B, in which the SꢀO bond in S(VI)
is formally added to a ruthenium centre have been
characterised and shown to oxidise phosphines to phos-
phine oxides [11], and sulfinate complexes of ruthenium
analogous to D have also been reported [12]. However,
attempts to identify a sulfinated phosphine oxide in our
reaction mixtures by 13C NMR spectroscopy have not
been successful. The spectrum obtained from the reac-
tion between the propylsulfonated phosphine and
Scheme 4. Reactions of the sulfonated phosphines with Pt(II) in aqueous media. (i) Acidic aqueous solution+CODPtCl2 in chloroform. (ii)
PtCl42− initially. (iii) PtCl42− on standing. (iv) KOH. (v) Alkaline aqueous solution+CODPtCl2 in chloroform. (vi) Aqueous HCl. (vii) Bu4NBr
reflux in chloroform. (viii) Pt(II) in alkaline solution.

J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
193
1JPPt 3710 (L− =Ph2P(CH2)4SO3−). The small upfield
Table 3
31P NMR data for Pt(Ph2P(CH2)nSO2O)2 in CHCl3
shift relative to the chloro complexes is as expected, and
1
the values of JPPt are consistent with P trans to Br [17],
cis
trans
the compounds are thus tentatively assigned as cis-
PtBr2(LNBu4)2 (7). The small amounts of material iso-
lated in these reactions have precluded further
characterisation. The observed reactions are summarized
in Scheme 4
n
l
1JPPt
l
1JPPt
(6a)
(6b)
(6c)
(6d)
2
3
4
12.4
18.7
18.9
4352
4316
4369
not observed
not observed
18.0
3047
2.2.4. Electrospray mass spectrometry
Electrospray mass spectrometry has been shown to be
a powerful technique for the study of inorganic com-
plexes in solution [18], and has been used to study metal
complexes in both organic [19] and aqueous systems [20].
Its utility stems from the mild transfer of ions from
solution into the gas phase, allowing ions present in
solution to be directly observable in the mass spectra.
The biphasic reactions of CODPtCl2 in CHCl3 with
alkaline solutions of the phosphines gave oxidised phos-
phine in the aqueous layer as the major product, and
small amounts of a platinum complex assigned as the
cis-chelate PtL2 (6a–c), in chloroform (Scheme 4). The
assignment of the complexes as O-bonded cis-chelates is
1
supported by the large values of JPPt consistent with P
trans to a weakly s-bonding oxygen. The NMR data are
shown in Table 3. While the high PPt coupling constant
is also consistent with a Pt(0) species, the reactions and
other spectroscopic evidence described below indicate the
2.2.4.1. Positi6e ionisation spectra. Since no platinum and
palladium containing cations are expected to be present
in aqueous solutions of Pt/PdCl2(LNa/K)2 the electro-
spray mass spectra obtained in the positive ionisation
mode will not be directly informative as to the solution
species. While the spectra do show the presence of
platinum and palladium containing ions, their identifica-
tion is not straightforward and investigations into the
behaviour of the complexes under positive ionisation
electrospray conditions are continuing.
metal is present as Pt(II). For the isolated solid (L−
=
Ph2P(CH2)2SO3−), the SO region of the IR spectrum is
considerably more complex than would be expected for
the uncoordinated –SO3− group in Pt(0) complexes such
as Pt(LM)4, which is consistent with the lowering of the
local symmetry from C36 to Cs expected on coordination.
While the ethyl and propyl sulfonated phosphines give
only one complex, when L− =Ph2P(CH2)4SO3− the
presence of two equal intensity signals, one with a
considerably lower PPt coupling constant, indicates the
presence of both cis- and trans-chelates. The formulation
as platinum(II) is further supported by the fact that the
platinum can be extracted into aqueous solution as 1 by
equilibration with concentrated HCl, and that ring
opening of the chelates can also be achieved on pro-
longed reflux of the chloroform solutions with tetrabuty-
lammonium bromide. Here the 31P NMR spectra of the
reaction mixtures show the gradual formation of species
l −4.0 1JPPt 3716 (L− =Ph2P(CH2)2SO3−) and l −2.9
2.2.4.2. Negati6e ionisation spectra. The negative ion
spectra are considerably simpler, and the data for the
platinum complexes are collected in Table 4. At low cone
voltages (−20 V) the base peaks at m/z 797 (ethyl), 825
(propyl) and 853 (butyl) are independent of the cation
and assigned to [PtL2(OH)]−. This ion is not present in
the original aqueous solution, and is presumably formed
by loss of HCl and Cl− from the expected hydrated
[PtCl2L2]2− ions. The formation of platinum phosphine
hydroxo complexes in aqueous systems is well known
[21,22]. Ions at m/z 293 (ethyl), 307 (propyl) and 321
(butyl) due to L− are present in all spectra. At −50 V
Table 4
Negative ionisation electrospray mass spectral data for PtCl2(Ph2P(CH2)nSO3Na/K)2 (n=2, 4) and [PtCl(Ph2P(CH2)3SO3Na/K)3]Cl in aqueous
solution
Assignment
PtCl2(Ph2P(CH2)2SO3Na/K)2
[PtCl(Ph2P(CH2)3SO3Na/K)3]Cl
PtCl2(Ph2P(CH2)4SO3Na/K)2
Meas.
(Calc.a)
Meas.
(Calc.)
Meas.
(Calc.)
[L]−
293.0
308.9
–
(293.0)
(309.0)
307.0
323.0
566.1
574.9
825.1
843.0
(307.1)
(323.1)
(566.1)
(575.1)
(825.1)
(843.0)
320.9
336.9
–
(321.0)
(337.0)
[LO]−b
[PtL3OH]2−
[PtL3Cl]2−
[PtL2(OH)]−
[PtL2Cl]−
–
–
796.9
–
(797.0)
853.3
(853.1)
a Monoisotopic masses employed for measured and calculated m/z values.
b Intensity of this ion increases with cone voltage—not significant in the [PtCl(Ph2P(CH2)3SO3Na/K)3]Cl spectrum at 20 V cone.

194
J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
Fig. 1. Negative ion electrospray mass spectrum of [PtCl(Ph2P(CH2)3SO3Na/K)3]Cl. Inset: (A) Theoretical isotope profile of
[Pt(Ph2P(CH2)3SO3)2(OH)]− and (B) maximum entropy reconstructed spectrum of observed data.
considerable fragmentation is observed with the metal
containing ions being much reduced in intensity. The base
peaks appearing at m/z 309 (ethyl), 323 (propyl) and 337
(butyl) are tentatively assigned as the phosphine oxides.
Phosphine complexes have previously been shown to give
phosphine oxides under conditions of electrospray ioni-
sation [23].
reference (H3PO4, K2PtCl6 and TMS for 31P, 195Pt and
13C, respectively). The phosphines were prepared by
literature methods [6,7] and stored in vacuo. CODPtCl2
was prepared in a 95% yield by a literature method [24].
Electrospray mass spectra were recorded on a VG
Quattro II triple quadrupole mass spectrometer. Samples
in solution were loop injected into a stream of water/
methanol (1:1) passing through a steel capillary held at
high voltage (+3.5 KV for positive mode, −3.0 KV for
negative mode). Nebulisation of the resulting spray was
pneumatically assisted by a concentric flow of nitrogen,
and desolvation aided by a flow of nitrogen bath gas and
heated source (70°C). Declustering and molecular frag-
mentation was promoted by increasing the cone voltage
from 20 to 90 V.
The spectra for PdCl2(LK)2 show features correspond-
ing to their platinum analogues.
The spectrum of [PtCl(Ph2P(CH2)3SO3Na/K)3]Cl is
shown in Fig. 1 and yields, in addition to peaks due to
[Pt(L)2(OH)]− at m/z 825 and [Pt(L)2(Cl)]− at m/z 843,
an intense metal containing ion at m/z 575 which has been
assigned to [PtCl(Ph2P(CH2)3SO3)3]2−. This complex is
observed in the 31P NMR spectra.
The spectra of the acid complexes 1 in methanol show
slightly different characteristics, with the base peaks at
m/z 817 (ethyl) and 845 (propyl) assigned to [PtClL2]−
formed by loss of chloride from [PtCl2L2]2− together with
L− at m/z 293 (ethyl) and m/z 307 (propyl). In the propyl
complex a low intensity peak at m/z 881 is observed and
assigned as [M–H]−, while the intense peak at m/z 440
represents the [M–2H]2− ion. The spectra for the propyl
complex together with observed and theoretical isotope
profiles for the [M–H]− ion are shown in Fig. 2.
3.1. Reaction between propylsultone and
diphenylphosphine
The sultone (0.53 g, 4.34 mmol) and diphenylphosphine
(0.75 ml, 4.31 mmol) were heated to 60°C in dry THF
for 2 days after which time a colourless insoluble resin
had formed. This was separated and dissolved in ethanol,
the 31P NMR spectrum of which showed a signal at 29.5
ppm due to the zwitterionic phosphonium salt.
3.2. cis-PtCl2(Ph2P(CH2)2SO3H)2 · 3.5H2O (1) and
trans-PtCl2(Ph2P(CH2)2SO3H)2 (2)
3. Experimental
All NMR spectra were recorded on a JEOL FX90Q
with shifts measured relative to the appropriate external
In a typical preparation COD PtCl2 (0.60 g, 1.60 mmol)
in dichloromethane (25 ml) was added dropwise to a

J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
195
Fig. 2. Negative ion electrospray mass spectrum of [PtCl2(Ph2P(CH2)3SO3H)2]. Inset: (A) theoretical isotope profile for [M–H]− ion. (B) Observed
isotope profile for [M–H]− ion.
stirred solution of the phosphine (1.01 g, 3.20 mmol) in
35 ml concentrated HCl. The aqueous layer was sepa-
rated and the precipitated trans-isomer filtered off,
washed with acetone and dried in vacuo to give 0.10 g
(7%) as a tan coloured solid. The filtrate was allowed to
evaporate to about 5 ml at 0°C and the white solid was
filtered and dried in vacuo to give 0.41 g (28%) of the
cis isomer. Anal. Required for the trans isomer C,
39.36; H, 3.54. Found: C, 39.71; H, 3.22%. Required
for the cis isomer C, 36.65; H, 4.06. Found: C, 36.61;
H, 3.87%.
resulting precipitates were filtered and dried in vacuo.
Representative preparations are described below.
3.4. cis-PtCl2(Ph2P(CH2)3SO3Na0.47K0.53)2 · 2H2O (3a)
K2PtCl4 (0.31 g, 0.75 mmol) in water (2.5 ml) and the
phosphine (0.51 g, 1.52 mmol) in 7.5 ml gave 0.27 g
(37%) of a cream coloured solid. Anal. Required C,
36.78; H, 3.70; K, 4.26. Found: C, 36.87; H, 3.68; K,
4.26%.
3.3. PtCl2(LNa/K)2 (3) and PdCl2(LNa/K)2 (4)
3.5. cis-PtCl2(Ph2P(CH2)3SO3K)2 · 2H2O (3b)
For these complexes the same general procedure was
followed. An aqueous solution of K2PtCl4 or K2PdCl4
was added to a suspension of the phosphine. In all
cases the solution cleared during addition and the com-
plexes were isolated by slow evaporation at 5°C. The
K2PtCl4 (0.30 g, 0.72 mmol) in water (2.5 ml) and the
phosphine (0.50 g, 1.44 mmol) in 7.5 ml water gave 0.17
g (24%) of a cream coloured solid. Anal. Required C,
36.22; H, 3.65; K, 7.84. Found: C, 36.04; H, 3.53; K,
7.54%.

196
J.L. Wedgwood et al. / Inorganica Chimica Acta 290 (1999) 189–196
3.6. cis-PtCl2(Ph2P(CH2)4SO3K)2 · 2H2O (3c)
References
[1] (a) J.W. Ellis, K.N. Harrison, P.A.T. Hoyle, A.G. Orpen, P.G.
Pringle, M.B. Smith, Inorg. Chem. 31 (1992) 3026. (b) P. Stobel,
H.A. Mayer, F. Auer, Eur. J. Inorg. Chem. 37 (1998) 37. (c) C.J.
Smith, V.S. Reddy, K.V. Katti, J. Chem. Soc., Dalton Trans.
(1998) 1365.
[2] (a) T. Okano, Y. Moriyama, H. Konishi, J. Kiji, Chem. Lett.
(1986) 1463. (b) Y. Amrani, D. Sinou, J. Mol. Catal. 36 (1986)
319.
[3] B. Mohr, D.M. Lynn, R.H. Grubbs, Organometallics 15 (1996)
4317. (b) M.K. Markiewicz, M.C. Baird, Inorg. Chim. Acta 113
(1986) 95.
[4] See for example references in W.A. Herrmann, C.W.
Kohlpainter, Angew. Chem., Int. Ed. Engl. 32 (1993) 1524 and
F. Joo, A. Katho, J. Mol. Catal. 116 (1997) 3.
K2PtCl4 (0.29 g, 0.69 mmol) in water (2.5 ml) and the
phosphine (0.49 g, 1.39 mmol) in water (7.5 ml) gave 0.29
g (41%) of a cream coloured solid. Anal. Required C,
37.58; H, 3.94; K, 7.63. Found: C, 37.08; H, 3.75; K,
7.85%.
3.7. [PtCl(Ph2P(CH2)3SO3Na0.67K0.33)3]Cl · 3H2O (5)
A solution of K2PtCl4 (0.30 g, 0.72 mmol) in 2.5 ml
water and the phosphine (0.72 g, 2.17 mmol) in 8.0 ml
water gave 0.33 g (35%) of a white solid. Anal. Required
C, 40.73; H, 4.10; K, 2.91. Found: C, 40.76; H, 4.19; K,
2.47%.
[5] (a) B. Cornils, E. Wiebus, Chemtech 25 (1995) 33. (b) A.G.
Abatjoglou, D.R. Bryant, R.A. Peterson, US Patent 5,180,854
(1993). (c) B. Cornils, W.A. Herrmann, R.W. Eckl, J. Mol.
Catal. A 116 (1997) 27.
3.8. PdCl2(Ph2P(CH2)3SO3Na0.47K0.53)2 · 3H2O (4a)
[6] S. Ganguly, J.T. Mague, D.M. Roundhill, Inorg. Chem. 31
(1992) 3500.
[7] (a) E. Paetzold, G. Oehme, Phosphorus, Sulfur Silicon 51/52
(1990) 359. (b) E. Paetzold, A. Kinting, G. Oehme, J. Prakt.
Chem. 329 (1987) 725.
[8] J.E. Huheey, E.A. Keiter, R.L. Keiter, Inorganic Chemistry,
Principles of Structure and Reactivity, 4th ed., Harper Collins,
New York, 1993.
K2PdCl4 (0.25 g, 0.76 mmol) in water (5 ml) and the
phosphine (0.50 g, 1.52 mmol) in 5 ml water gave 0.29
g (44%) of a pale yellow solid. Anal. Required C, 39.64;
H, 4.21; K, 4.55. Found: C, 39.84; H, 3.87; K, 4.60%.
3.9. PdCl2(Ph2P(CH2)3SO3K)2 · 3H2O (4b)
[9] P.-H. Leung, G.H. Quek, H. Lang, A.M. Liu, K.F. Mok, A.J.P.
White, D.J. Williams, N.R. Rees, W. McFarlane, J. Chem. Soc.,
Dalton Trans. (1998) 1639.
[10] W.M. Latimer, Oxidation Potentials, 2nd ed., Prentice Hall,
Englewood Cliffs, NJ, 1952, CRC Handbook of Chemistry and
Physics 61st ed., CRC press, Boca Raton, FL, 1981.
[11] E. Dombrowski, W.A. Schenk, Angew. Chem., Int. Ed. Engl. 34
(1995) 1008.
[12] (a) W.A. Schenk, J. Bezler, Eur. J. Inorg. Chem. (1998) 605. (b)
References in W. Weigland, R. Wunsch, Chem. Ber. 129 (1996)
1409.
[13] C. Larpent, R. Dabard, H. Patin, Inorg. Chem. 26 (1987) 2922.
[14] D.M. Blake, D.M. Roundhill, Inorg. Synth. 18 (1978) 20.
[15] P.S. Pregosin, Annu. Rep. NMR Spectrosc. 17 (1986) 285.
[16] E. Lovattani, I. Moldes, J Saudes, J.F. Piniella, A. Alvarez
Larena, Organometallics 17 (1998) 3394.
K2PdCl4 (0.24 g, 0.72 mmol) in water (2.5 ml) and the
phosphine (0.52 g, 1.45 mmol) in 5 ml water gave 0.15
g (23%) of a pale yellow powder. Anal. Required C, 39.00;
H, 4.15; K, 8.44. Found: C, 38.90; H, 3.75; K, 8.10%.
3.10. PdCl2(Ph2P(CH2)4SO3K)2 · xH2O (4c) and
Pd2Cl4(Ph2P(CH2)4SO3K)2 · 4H2O (6)
K2PdCl4 (0.24 g, 0.72 mmol) in water (2.5 ml) was
added to a stirred suspension of the phosphine (0.50 g,
1.44 mmol) in 5 ml water. The mixture cleared on mixing
giving a deep red coloured solution from which a small
quantity of the dimer precipitated as red solid (0.01 g).
Anal. Required C, 33.49; H, 3.86. Found: C, 32.98; H,
3.74%. A small quantity of yellow solid formed on
standing and is thought to be the 2:1 complex. There was
insufficient material for elemental analysis.
[17] P.S. Pregosin, R.W. Kunz, 31P and 13C NMR of Transition
Metal Phosphine Complexes, Springer, Berlin, 1979.
[18] (a) C.E.C.A. Hop, R. Bakhtiar, J. Chem. Educ. 73 (1996) A162.
(b) R. Colton, A. D’Agostino, J.C. Traeger, Mass Spectrom.
Rev. 14 (1995) 79.
[19] M.J. Deery, T. Fernandez, O.W. Howarth, K.R. Jennings, J.
Chem. Soc., Dalton Trans. (1998) 2177.
[20] J.M. Law, W. Henderson, B.K. Nicholson, J. Chem. Soc.,
Dalton Trans. (1997) 4584.
Acknowledgements
We thank the EPSRC for the use of the National Mass
Spectrometry Service at the University of Swansea. We
are also very grateful to Dr John Fawcett of the Leicester
University for his tireless efforts to find single crystals of
many of the complexes. We are also grateful to the Royal
Society of Chemistry for financial support from the
Research Fund for the preliminary work in this area and
to Johnson Matthey for the generous loan of K2PtCl4.
[21] (a) G. Trovo, B. Longato, B. Corain, A. Tapparo, A. Furlani, V.
Scarcia, B. Baccichetti, F. Borodin, M. Palumbo, J. Chem. Soc.,
Dalton Trans. (1993) 1547. (b) E. Costa, M. Murray, P.G.
Pringle, M.B. Smith, Inorg. Chim. Acta 213 (1993) 25.
[22] J.J. Li, W. Li, P.R. Sharp, Inorg. Chem. 35 (1996) 604.
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(1992) 1030.
[24] J.X. McDermott, J.F. White, G.M. Whitesides, J. Am. Chem.
Soc. 98 (1976) 6521.
.