New S/O-substituted ferrocenediyl ligands and their metal complexes

Article abstract of DOI:10.1039/b602576e

New unsymmetrical S/O 1,1′-disubstituted ferrocenediyl ethers and hydroxides have been synthesised. The coordination chemistry of 1-(methylsulfanyl)-1′-(methoxy)ferrocene 6 has been investigated with palladium(ii) and platinum(ii) precursors. With palladium(ii), a bis - chloro-bridged dimeric complex 10 was obtained with the ligand bound solely through the thioether donor group. With platinum(ii), a bis-ligand trans-sulfur ligated complex 11 was obtained and structurally characterised. The Royal Society of Chemistry 2006.

Full text of DOI:10.1039/b602576e

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www.rsc.org/dalton | Dalton Transactions
New S/O-substituted ferrocenediyl ligands and their metal complexes†
Robert C. J. Atkinson, Vernon C. Gibson,* Nicholas J. Long,* Lara J. West and Andrew J. P. White
Received 20th February 2006, Accepted 11th April 2006
First published as an Advance Article on the web 28th April 2006
DOI: 10.1039/b602576e
New unsymmetrical S/O 1,1ꢀ-disubstituted ferrocenediyl ethers and hydroxides have been synthesised.
The coordination chemistry of 1-(methylsulfanyl)-1ꢀ-(methoxy)ferrocene 6 has been investigated with
palladium(II) and platinum(II) precursors. With palladium(II), a bis-l-chloro-bridged dimeric complex
10 was obtained with the ligand bound solely through the thioether donor group. With platinum(II), a
bis-ligand trans-sulfur ligated complex 11 was obtained and structurally characterised.
and their use as alkali and transition metal complexing agents
Introduction
investigated.14 Although more stable than hydroxyferrocenes, their
The synthesis of ferrocenyl ligands featuring one or more donor
application as ligands in coordination chemistry is still relatively
scarce and warrants further study.15,16 Herein, we report the
synthesis of new S/O-substituted ferrocenediyl ligands and their
coordination chemistry with palladium and platinum precursors.
Thioether- and thiolate-substituted ferrocenyl ligands are con-
siderably less well studied than the corresponding phosphine
derivatives but have been shown to stabilise unusual metal
complexes.7,16–20 In addition, the application of ligands containing
hard oxygen and soft sulfur donor groups in catalysis is also a
growing area of importance and the beneficial effect of soft sulfur
donors on the activity of harder transition metal polymerisation
catalysts, such as titanium and zirconium, has been noted.21
heteroatoms has received a great deal of attention in recent years
and extensive studies into their coordination chemistry and
applications within catalysis have been undertaken.1,2 As well
as providing a rigid ligand framework with a wide bite angle,
the electronic (redox) properties of the ferrocene unit provide
the possibility of electrochemically controlling the reactivity
and binding at a metal centre.3 Planar chiral unsymmetri-
cally 1,2-disubstituted ferrocenes have found wide applications
in asymmetric catalysis and symmetrical 1,1ꢀ-disubstituted fer-
rocenes are common bidentate ligands in coordination chem-
istry (1,1ꢀ-bis{diphenylphosphino}ferrocene being employed most
prevalently).2,4 Unsymmetrically 1,1ꢀ-disubstituted ferrocenes fea-
turing hetero-combinations of N, P, S, Se or O atoms, usually
formed via bromo,5,6 lithio7,8 or stannyl9 intermediates, are less well
known but have received increasing attention in recent years—
for instance, we have recently published the synthesis of novel
1,1ꢀ-P/O ferrocenyl ethers (1, see Fig. 1)10 and hydroxyferrocenes
(2, 3).11
Results and discussion
Ligand synthesis
The use of bis(trimethylsilyl)peroxide in the preparation of met-
allocenyl hydroxides11,22 and trimethylsilylethers23 prompted its
application in the synthesis of 1-(bromo)-1ꢀ-(methoxy)ferrocene
4.10 From this starting material, a variety of sulfur heteroatom-
substituted ferrocenyl ethers have been synthesised as shown in
Scheme 1.
4 was reacted with one equiv. of n-butyllithium in a cooled
THF solution and the lithio-intermediate 5 quenched in situ
with different sulfur-containing electrophiles. 1-(Methylsulfanyl)-
1ꢀ-(methoxy)ferrocene 6 was obtained using dimethyl disulfide
as the quenching agent as an orange oil in 82% yield following
purification via column chromatography. The 1H NMR spectrum
of 6 shows two singlets at 2.28 and 3.66 ppm corresponding to the
SMe and OMe protons respectively. The cyclopentadienyl protons
show the expected four pseudo-triplets, indicating unsymmetrical
substitution of the cyclopentadienyl rings. Reaction of 5 with
diphenyl disulfide gave 7 as an orange crystalline solid in 59%
yield following purification via column chromatography. Again,
the 1H NMR spectrum confirmed the unsymmetrical substitution
of the cyclopentadienyl rings together with signals for the methoxy
and phenyl protons. We have recently reported the synthesis
of sterically hindered bis-sulfido-bridged dithioferrocenes18 and
have also investigated cleavage of the disulfide bridge in the
synthesis of unsymmetrical thioether-, thiol- and thioether-,
Fig. 1 1,1ꢀ-Ferrocenediyl ethers and hydroxides.
Ferrocene compounds containing hydroxyl-substituents and
their application in coordination chemistry are rare: their tendency
to decompose in air to cyclopentenone species makes their
synthesis and handling a challenge.12 Favourable intermolecular
hydrogen-bonding interactions were thought to stabilise these
hydroxyferrocenes allowing their structural characterisation and
coordination chemistry to be investigated. Recently, new synthetic
routes to ferrocenyl ethers have been developed.13 Ferrocene-
containing crown ethers and cryptands have been synthesised
Department of Chemistry, Imperial College London, London, UK SW7 2AZ.
E-mail: n.long@imperial.ac.uk; Fax: +44 (0)20 7594 5804; Tel: +44 (0)20
7594 5781
† Electronic supplementary information (ESI) available: X-Ray crystal
structure of 11. See DOI: 10.1039/b602576e
thioether-substituted ferrocenes.19
A novel ether-substituted
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interaction in particular would be expected to be considerably
stronger and indeed 3 was found to be air stable in the solid state
for at least one month.
The 1H NMR spectrum of 9 showed two broad pseudo-triplets
due to the cyclopentadienyl protons at 3.71 and 4.04 ppm together
with a multiplet at 4.33 ppm. The five phenyl protons showed a
triplet at 6.84 ppm corresponding to the para proton, a doublet of
doublets (observed as a triplet) at 6.97 ppm corresponding to the
meta protons and a doublet at 7.24 ppm corresponding to the ortho
1
protons. It was not possible to obtain a 13C{ H} NMR spectrum
as the sample decomposed in solution during collection of the
data. The positive ion FAB mass spectrum showed the molecular
ion (310 amu) but no fragmentation pattern was observed.
Coordination chemistry
The coordination chemistry of ligands 6, 7 and 8 was at-
tempted with palladium(II) and copper(I) precursors. A stable
metal complex could only be isolated and characterised suc-
cessfully using 6 and palladium(II) precursors however, and
despite repeated attempts, no metal complexes were obtained
with 7 and 8. Reaction of 7 and 8 with (1,5-cycloocta-
diene)palladium dichloride, bis(acetonitrile)palladium dichloride
or bis(benzonitrile)palladium dichloride led to decomposition
and recovery of unreacted ligand. Attempts to form copper(I)
complexes by reaction with tetrakis(acetonitrile)copper(I) hexaflu-
orophosphate led to similar results. The failure of 7 or 8 to form
stable coordination compounds with late transition metal precur-
sors, all of which had given stable compounds with the analogous
diphenylphosphino ligand 1, is attributed to the relatively poorer
donor ability of thioether donor groups compared to phosphines.
It should be noted that thioether complexes of Pd(II) and Cu(I)
are also abundant in the literature, but in the case of 7 and 8, the
combination of the hard methoxy donor group and arylsulfanyl or
disulfide donor atoms makes the ligand unsuitable for stabilising
palladium(II) and copper(I) centres.
A palladium(II) complex of 6 was successfully synthesised
by adding a toluene solution of 6 to a CH2Cl2 solution of
bis(benzonitrile)palladium dichoride. The reaction mixture was
stirred at room temperature overnight and solvent was then re-
moved in vacuo to give a green solid which was washed with hexane
and dried under vacuum. The complex, 10, exhibited an interesting
dichroic nature: solutions in acetonitrile, chloroform, toluene or
benzene are purple whereas solutions in dichloromethane are
green in colour as is the dried solid. The 1H NMR spectrum
of 10 shows two singlets at 2.33 and 3.22 ppm corresponding
to the SMe and OMe protons respectively. This indicates that
on coordination a downfield shift is observed for the thioether
protons, suggesting coordination of the sulfur heteroatom to the
palladium centre, whereas a slight upfield shift is observed for
the methoxy protons suggesting that they are not interacting with
the palladium centre. Interestingly, the cyclopentadienyl protons
show three well-resolved pseudo-triplets at 3.81, 3.98 and 4.05 ppm
and a very broad peak at 4.70 ppm. The positive FAB mass
spectrum shows a peak at 403 amu corresponding to 6·PdCl+
and a peak corresponding to the ligand (262 amu). Elemental
analysis indicates a 1 : 1 complex of formula 6·PdCl2. The
data suggest a 1 : 1 complex bound solely through the sulfur
heteroatom suggesting a three-coordinate palladium dichloride
Scheme 1 Reagents and conditions: (i) n-BuLi, THF, −78 ◦C, 10 min;
(ii) RSSR, THF, rt, 20 h; (iii) S2Cl2, THF, rt, 20 h; (iv) n-BuLi, THF,
−78 ◦C, 10 min; (v) TMSOOTMS, −78 ◦C, 1 h; (vi) hydrolysis.
bis-sulfido-bridged ferrocene was synthesised via reaction of 5
with freshly distilled sulfur chloride to give 8 as a brown oil
in 44% yield following purification via column chromatography.
The 1H NMR spectrum of 8 shows a singlet at 3.59 ppm
corresponding to the OMe protons. The cyclopentadienyl protons
show two pseudo-triplets at 3.82 and 4.07 ppm and a multiplet at
4.32 ppm. The positive FAB mass spectrum shows the molecular
ion (494 amu) and peaks corresponding to cleavage of the disulfide
bond (247 amu).
The hydroxyferrocenes 2 and 3 were found to be unexpectedly
stable which was thought to be due to intermolecular hydro-
gen bonding interactions. It was therefore decided to investi-
gate the synthesis of a thioether-substituted hydroxyferrocene
9 to probe this stabilising hydrogen bonding interaction fur-
ther. 1-(Phenylsulfanyl)-1ꢀ-(bromo)ferrocene was synthesised as
described by Dong and co-workers.5 It was then dissolved in
THF and cooled to −78 ◦C. One equivalent of n-butyllithium
was added followed by bis(trimethylsilyl)peroxide and the reaction
mixture was stirred at −78 ◦C for one hour before being warmed
to room temperature. Several attempts were required to isolate
pure 1ꢀ-(hydroxy)ferrocenediylphenylsulfide 9 as it was found to
decompose more readily in air than 2 or 3 and purification via
column chromatography was not possible. The best method was
found to be to dissolve the crude product in a 1 : 1 mixture of
5% potassium hydroxide solution and methanol under nitrogen
atmosphere to give an orange solution containing an orange
precipitate. The solution containing the product was isolated via
filtration and neutralised by adding solid CO2 until a yellow
precipitate was visible. The precipitate was extracted into diethyl
ether solution and the solvent removed in vacuo to leave 9 as a
yellow solid. 9 was obtained pure after washing with hexane at
◦
−78 C. Unfortunately it was not possible to grow a crystal of 9
suitable for X-ray diffraction, and it is proposed that the reason 9
was observed to decompose more readily than either 2 or 3 lies in
the fact that the S · · · H–O hydrogen bonding interaction would be
expected to be weaker than the corresponding hydrogen bonding
=
interactions in 2 or 3. The P O · · · H–O hydrogen bonding
3598 | Dalton Trans., 2006, 3597–3602
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complex. A three-coordinate palladium(II) complex is unlikely
(especially with a relatively sterically unencumbered ligand such
as 6) as palladium(II) complexes commonly adopt a square planar
geometry due to their d8 electronic configuration. For this reason,
together with the fact that the colour of the complex is solvent-
dependent (suggesting the potential for solvent coordination) the
structure shown in Scheme 2 is proposed.
the product to crystallise in 35% yield. The yield of the reaction
could be improved by reacting two equivalents of ligand per
platinum centre. In contrast, a chelating platinum dichloride
complex was formed with 1,1ꢀ-bis(methylthio)ferrocene20 and it
is thought that the presence of the harder methoxy donor group
in 6 causes the preferential formation of 11 rather than a chelated
1
complex. The H NMR spectrum in CDCl3 showed two singlets
at 2.67 and 3.65 ppm corresponding to the SMe and OMe
protons respectively together with signals corresponding to the
cyclopentadienyl protons. The ligand displays signals at 2.28 and
3.66 ppm in CDCl3 corresponding to the SMe and OMe protons
indicating that on coordination a downfield shift is observed
for the thioether protons, suggesting coordination of the sulfur
heteroatom to the platinum centre, whereas no shift is observed for
the methoxy protons suggesting that they are not interacting with
the platinum centre. The positive FAB mass spectrum showed the
molecular ion (790 amu) and a peak due to the ligand (262 amu).
Crystals of 11 suitable for X-ray diffraction analysis were grown
from a saturated CH2Cl2 solution which was layered with hexane
under a nitrogen atmosphere and the structure is shown in Fig. 2.
Scheme 2 Reagents and conditions: (i) (PhCN)2PdCl2, CH2Cl2/toluene,
rt, 20 h; (ii) (PhCN)2PtCl2, toluene, 60 ◦C, 20 h.
Complex 10 is green in colour in CH2Cl2 solution and in the
solid state but purple in colour in toluene, benzene, acetonitrile
and chloroform solution. It is likely that these solvents are able to
coordinate to the palladium centre breaking up the dimeric struc-
ture and causing a change in colour of the complex. Unfortunately,
despite repeated attempts, it was not possible to grow a crystal of
10 suitable for X-ray analysis. Such a chloride-bridged dimeric
complex has previously been structurally characterised contain-
5
5
ing the osmocene ligand [Os(g -C5H4PPh2)(g -C5H4P{O}Ph2)]
bound solely through the phosphine donor group.24 Cationic
Pd(BF4)2 complexes of 1,1ꢀ-bis[(alkyl)chalcogeno]ferrocenes have
been reported by Sato and co-workers.16 It is worth noting
that both the bis(methylthio)ferrocene and bis(methoxy)ferroene
palladium complexes were thought to bind in a chelating fashion
(although the methoxy version could not be characterised by
NMR spectroscopy or X-ray crystallography due to its sensitivity).
It might be expected, therefore, that the mixed SMe/OMe
ligand 6 should form a chelating complex in reactions with
bis(benzonitrile)palladium dichloride rather than the observed
complex 10, although no such chelating complex was detected.
The coordination chemistry of 6 was also investigated with
platinum precursors. A toluene solution of 6 was added to a
toluene suspension of bis(benzonitrile)platinum dichloride. The
reaction mixture was stirred at 60 ◦C overnight and some
precipitate observed was removed by filtration, the filtrate being
evaporated to dryness. The resulting orange powder was washed
with hexane and dried under vacuum. Analysis by 1H NMR
spectroscopy showed that the product consisted of a mixture of
unreacted bis(benzonitrile)platinum dichloride and a bis ligand
trans-sulfur ligated platinum complex bis[1-(methylsulfanyl-jS)-
1ꢀ-(methoxy)ferrocene]platinum dichloride 11. The mixture was
purified by dissolving in CH2Cl2 and layering with hexane causing
Fig. 2 The molecular structure of the centrosymmetric complex 11.
Selected bond lengths (A) and angles ( ): Pt–Cl 2.2995(8), Pt–S 2.3088(7);
Cl–Pt–Clꢀ 180, Cl–Pt–S 95.70(3), Cl–Pt–Sꢀ 84.30(3), S–Pt–Sꢀ 180.
◦
˚
The coordination geometry at platinum is only slightly distorted
square planar, the {PtCl2S2} plane being completely flat, a
consequence of the metal atom being positioned on a centre of
symmetry. With the Pt–Cl and Pt–S bond lengths being very
˚
similar [2.2995(8) and 2.3088(7) A respectively] the main distortion
is in the Cl–Pt–S angles which are 84.30(3) and 95.70(3)◦; the
platinum coordination distances themselves are unexceptional.25
The S–Me carbon atom is near coplanar with the coordination
plane, the Cl–Pt–S–Me torsion angle being ca. 15◦. The S-
substituted Cp ring, therefore, is steeply inclined (ca. 99◦) to the
PtCl2S2 plane.
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NMR d(CDCl3) ppm: 20.6 (SCH3), 57.5 (OCH3), 56.2, 63.3, 69.0,
72.1, 83.5, 127.9 (C5H4); m/z: 262 (M+), 216 (M+ − SMe).
Conclusions
The coordination chemistry of unsymmetrical 1,1ꢀ-disubstituted
ferrocenediyl ligands that lack a phosphine donor moiety is
underdeveloped, mainly due to the many applications of phos-
phine ligands in homogeneous catalysis driving research into
coordination chemistry with phosphine ligands. Ferrocenyl ether
ligands in particular and, to a lesser extent, ferrocenyl thioethers
have been little studied as ligands in coordination chemistry but
have excellent scope for the stabilisation of new and interesting
coordination complexes. Despite the low steric demands of 6,
the coordination chemistry with palladium(II) and platinum(II)
is still dominated by the thioether donor group and even when
carefully controlling the reaction stoichiometry, complexes with
pendant methoxy groups were obtained. The observation that
the methoxy donor group interacts at best only weakly with the
metal centre suggests potential applications for ligands derived
from 6 in hemilabile catalysis.26 The coordination chemistry of
other 1,1ꢀ-unsymmetrical N/O ferrocenediyl ligands has also been
investigated and will be reported in a separate publication.
Synthesis of 1-(phenylsulfanyl)-1ꢀ-(methoxy)ferrocene (7).
4
(0.540 g, 1.83 mmol, 1 eq.) was dissolved in dry THF (30 cm3)
and cooled to −78 ◦C. To this solution was added n-butyllithium
(1.6 M in hexanes, 1.14 cm3, 1.83 mmol, 1 eq.) and the solution
stirred at −78 ◦C for 10 minutes. Diphenyl disulfide (0.710 g,
2.19 mmol, 1.2 eq.) dissolved in THF (5 cm3) was added and the
mixture allowed to warm to room temperature. The solution was
stirred at room temperature for 20 h and the solvent was removed
in vacuo and the residue redissolved in CH2Cl2 (50 cm3). Water was
added (3 × 25 cm3) and the layers separated. The organic layer was
dried (MgSO4) and the solvent removed in vacuo to yield a brown
oil. The crude mixture was purified by column chromatography
(neutral grade II alumina, petroleum spirit bp 40–60 ◦C/toluene,
4 : 1) to give pure 7 as an orange solid (0.35 g, 1.1 mmol, 59%).
Anal. Calc. for C17H16FeOS: C 62.98, H 4.97%, Found: C 63.11, H
4.84%; 1H NMR d(CDCl3) ppm: 3.70 (s, 3H, OCH3) 3.94 (t, 2H,
C5H4), 4.18 (t, 2H, C5H4), 4.39 (t, 2H, C5H4), 4.43 (t, 2H, C5H4),
1
7.05 (m, 3H, C6H5), 7.17 (m, 2H, C6H5); 13C{ H} NMR d(CDCl3)
ppm: 57.6 (OCH3), 56.3, 63.5, 70.6, 75.3, 75.7, 128.3 (C5H4), 124.8,
125.7, 128.6, 140.8 (C6H5); m/z: 324 (M+), 216 (M+ − SPh).
Experimental
Synthesis of di[1ꢀ-(methoxy)ferrocene]disulfide (8). 4 (0.800 g,
General procedures
2.71 mmol, 1 eq.) was dissolved in dry THF (30 cm3) and cooled
All preparations were carried out using standard Schlenk
techniques.27 All solvents were distilled over standard drying
agents under nitrogen directly before use, and all reactions were
carried out under an atmosphere of nitrogen. Chromatographic
separations were carried out on alumina (neutral grade II, 3%
H2O). 1H NMR spectra were recorded using a Delta upgrade on
a JEOL EX270 MHz spectrometer operating at 270.1 MHz (1H).
◦
to −78 C. To this solution was added n-butyllithium (1.6 M in
hexanes, 1.69 cm3, 2.71 mmol, 1 eq.) and the solution stirred at
−78 ◦C for 10 minutes. Freshly distilled sulfur chloride (0.10 cm3,
1.3 mmol, 0.48 eq.) was added and the mixture allowed to warm to
room temperature. The solution was stirred at room temperature
for 20 h and the solvent was removed in vacuo and the residue
redissolved in CH2Cl2 (50 cm3). Water was added (3 × 25 cm3)
and the layers separated. The organic layer was dried (MgSO4)
and the solvent removed in vacuo to yield an orange oil. The crude
mixture was purified by column chromatography (neutral grade
II alumina, hexane/toluene, 1 : 5) to give pure 8 as a brown oil
(0.29 g, 0.60 mmol, 44%). Anal. Calc. for C22H22Fe2O2S2: C 53.46,
1
13C{ H} NMR spectra were obtained on either a Bruker DRX-400
or AM-500 spectrometer. Chemical shifts (d) are reported in ppm
using the residual proton impurities in the NMR solvent as an
internal reference. Mass spectra were recorded using positive FAB
methods, on an Autospec Q mass spectrometer. Microanalyses
were carried out at Department of Health and Human Sciences,
London Metropolitan University.
1
H 4.49%, Found: C 53.64, H 4.58%; H NMR d(CDCl3) ppm:
3.59 (s, 3H, OCH3) 3.82 (t, 2H, C5H4), 4.07 (t, 2H, C5H4), 4.32
1
(m, 4H, C5H4); 13C{ H} NMR d(CDCl3) ppm: 57.5 (OCH3), 56.1,
63.3, 70.7, 74.2, 82.3, 128.2 (C5H4); m/z: 494 (M+), 247 (M+
Fc(S)(OMe)).
−
Syntheses
Synthesis of 1-(methylsulfanyl)-1ꢀ-(methoxy)ferrocene (6).
4
(0.800 g, 2.71 mmol, 1 eq.) was dissolved in dry THF (30 cm3)
and cooled to −78 ◦C. To this solution was added n-butyllithium
(1.6 M in hexanes, 1.69 cm3, 2.71 mmol, 1 eq.) and the solution
Synthesis of 1ꢀ-(hydroxy)ferrocenediylphenylsulfide (9). 1-
(Phenylsulfanyl)-1ꢀ-(bromo)ferrocene (0.30 g, 0.80 mmol, 1 eq.)
was dissolved in dry THF (20 cm3) and cooled to −78 ◦C. To
this solution was added n-butyllithium (1.6 M solution in hexane,
0.50 cm3, 0.80 mmol, 1 eq.) and the solution stirred at −78 ◦C for
10 min. Bis(trimethylsilyl)peroxide (0.13 cm3, 1.2 mmol, 1.5 eq.)
was added and the solution stirred at −78 ◦C for 1 h before being
allowed to warm to room temperature and stirred for 1 h. The
solvent was removed in vacuo and the residue redissolved in 5%
KOH/methanol, 1 : 1, and stirred vigorously for 10 minutes. The
mixture was filtered and solid CO2 added to the filtrate piece by
piece until a light yellow precipitate was observed to form. The
reaction mixture was extracted with diethyl ether (2 × 25 cm3)
and the organic layer dried (Na2SO4) and evaporated to dryness.
The resulting precipitate was washed with cold hexane (5 cm3) to
yield 9 as a yellow powder (0.048 g, 0.15 mmol, 19%). Anal. Calc.
◦
stirred at −78 C for 10 minutes. Dimethyl disulfide (0.29 cm3,
3.3 mmol, 1.2 eq.) was added and the mixture allowed to warm to
room temperature. The solution was stirred at room temperature
for 20 h and the solvent was removed in vacuo and the residue
redissolved in CH2Cl2 (50 cm3). Water was added (3 × 25 cm3)
and the layers separated. The organic layer was dried (MgSO4)
and the solvent removed in vacuo to yield an orange oil. The crude
mixture was purified by column chromatography (neutral grade
II alumina, petroleum spirit bp 40–60 ◦C) to give pure 6 as an
orange oil (0.59 g, 2.2 mmol, 82%). Anal. Calc. for C12H14FeOS:
C 54.98, H 5.38%, Found: C 54.92, H 5.34%; 1H NMR d(CDCl3)
ppm: 2.28 (s, 3H, SCH3) 3.66 (s, 3H, OCH3) 3.85 (t, 2H, C5H4),
4.08 (t, 2H, C5H4), 4.20 (t, 2H, C5H4), 4.32 (t, 2H, C5H4); 13C{ H}
1
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for C16H14FeOS: C 61.95, H 4.55%, Found: C 61.87, H 4.34%; 1H
NMR d(C6D6) ppm: 3.71 (t, 2H, C5H4), 4.04 (m, 4H, C5H4), 4.33
(t, 2H, C5H4), 6.84 (t, 1H, SC6H5), 6.97 (t, 2H, SC6H5), 7.84 (d,
2H, SC6H5); m/z: 310 (M+).
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Synthesis of [{1-(methylsulfanyl-jS)-1ꢀ-(methoxy)ferrocene}-
palladium chloride(l-chloride)]2 (10). 6 (0.075 g, 0.29 mmol, 1.1
eq.) was dissolved in dry toluene (3 cm3) and added via cannula
to a solution of bis(benzonitrile)palladium dichloride (0.100 g,
0.260 mmol, 1 eq.) dissolved in dry CH2Cl2 (7 cm3) and the reaction
mixture was stirred at room temperature for 20 h. The solvent was
removed in vacuo and the residue washed with dry hexane (2 ×
10 cm3) and dried under vacuum to yield 10 as a green solid
(0.062 g, 0.071 mmol, 49%). Anal. Calc. for C24H28Cl4Fe2O2Pd2S2:
1
C 32.80, H 3.21%, Found: C 32.69, H 3.26%; H NMR d(C6D6)
ppm: 2.32 (s, 3H, SCH3), 3.22 (s, 3H, OCH3), 3.81 (t, 2H, C5H4),
1
3.98 (t, 2H, C5H4), 4.05 (t, 2H, C5H4), 4.70 (br, 2H, C5H4); 13C{ H}
NMR d(C6D6) ppm: 22.8 (SCH3), 57.3 (OCH3), 57.1, 64.4, 70.4,
70.6, 81.3, 128.0 (obscured by solvent) (C5H4); m/z: 403 (LPdCl+),
262 (L+).
Synthesis of bis[1-(methylsulfanyl-jS)-1ꢀ-(methoxy)ferrocene]-
platinum dichloride (11). 6 (0.134 g, 0.510 mmol, 1.1 eq.) was
dissolved in dry toluene (10 cm3) and added via cannula to
a suspension of bis(benzonitrile)platinum dichloride (0.220 g,
0.460 mmol, 1 eq.) in dry toluene (10 cm3) at 60 ◦C. The reaction
mixture was stirred at 60 ◦C for 20 h before being filtered and the
filtrate evaporated to dryness. The resulting orange powder was
washed with hexane (10 cm3) and dried under vacuum. Further
purification was achieved by redissolving the product in CH2Cl2
and layering with hexane causing the product to crystallise out.
The crystals were isolated via filtration and dried under vacuum to
yield 11 as an orange crystalline solid (0.064 g, 0.081 mmol, 35%).
Anal. Calc. for C24H28Cl2Fe2O2PtS2: C 36.48, H 3.57%, Found: C
36.49, H 3.51%; 1H NMR d(CDCl3) ppm: 2.67 (s, 3H, SCH3), 3.65
(s, 3H, OCH3), 4.11 (br t, 2H, C5H4), 4.31 (br t, 2H, C5H4), 4.39
9 J. A. Adeleke, Y.-W. Chen and L.-K. Liu, Organometallics, 1992, 11,
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1
(br, 4H, C5H4); 13C{ H} NMR d(CDCl3) ppm: 23.7 (SCH3), 57.8
(OCH3), 56.9, 64.4, 70.4, 72.1, 79.8, 128.2 (C5H4); m/z: 790 (M+),
262 (L+).
Crystal data for 11. C24H28Cl2Fe2O2PtS2, M = 790.27, mono-
clinic, P21/c (no. 14), a = 10.1812(5), b = 7.9632(3), c = 15.9154(7)
◦
3
˚
˚
A, b = 95.796(4) , V = 1283.74(10) A , Z = 2 (Ci symmetry), Dc =
2.044 g cm−3, l(Mo-Ka) = 6.942 mm−1, T = 173 K, orange blocks,
Oxford Diffraction Xcalibur 3 diffractometer; 4371 independent
measured reflections, F2 refinement, R1 = 0.030, wR2 = 0.058, 4271
independent observed absorption-corrected reflections [|Fo| >
4r(|Fo|), 2hmax = 65◦], 152 parameters.
19 J. R. Dilworth, P. Arnold, D. Morales, L.-Y. Wong and Y. Zheng, Mod.
Coord. Chem., 2002, 217.
20 E. W. Abel, N. J. Long, K. G. Orrell, A. G. Osborne and V. Sik,
J. Organomet. Chem., 1991, 405, 375–382.
CCDC reference number 292849.
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b602576e
21 D. C. H. Oakes, B. S. Kimberley, V. C. Gibson, D. J. Jones, A. J. P. White
and D. J. Williams, Chem. Commun., 2004, 2174–2175; C. Capacchione,
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22 C. Elschenbroich, F. Lu and K. Harms, Organometallics, 2002, 21,
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1999, 10, 4095–4097; O. Riant, O. Samuel, T. Flessner, S. Taudien and
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Acknowledgements
We acknowledge financial support from the Department of
Chemistry, Imperial College London. Johnson Matthey plc are
thanked for the loan of precious metal salts.
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©