Thiocarbyl ligands via elimination of pentafluorobenzene at a diiron centre: Crystal structures of [Fe2(CO)4 {μ-SC(Ph)=CH}(μ-dppm)] and [Fe2(CO)4 {μ-SCH=C(Ph)C(O)}(μ-dppm)]

Article abstract of DOI:10.1016/S0022-328X(03)00135-9

Reaction of [Fe₂(CO)₆{μ-O=C-C(Ph)=CH ₂}(SC₆F₅)] with bis(diphenylphosphino) methane (dppm) at 110 °C affords the alkenyl complex [Fe₂(CO)₄(μ-HC=CHPh)(μ-SC₆ F₅)(μ-dppm)] together with the novel complexes [Fe₂(CO)₄{μ-SC(Ph)=CH}(μ-dppm)] and [Fe₂(CO)₄{μ-SCH=C(Ph)C(O)}(μ-dppm)] resulting from elimination of pentafluorobenzene. Both have been characterised crystallographically, the hydrocarbyl units acting as six-electron donors. The thioalkyne complex [Fe₂ (CO)₄{μ-SC(Ph)=CH}(μ-dppm)] exists as cis and trans isomers. Both are fluxional and interconvert at higher temperatures as shown by 2D NMR.

Full text of DOI:10.1016/S0022-328X(03)00135-9

Journal of Organometallic Chemistry 672 (2003) 22Á28
/
www.elsevier.com/locate/jorganchem
Thiocarbyl ligands via elimination of pentafluorobenzene at a diiron
centre: crystal structures of [Fe2(CO)4{m-SC(Ph)ÄCH}(m-dppm)] and
[Fe2(CO)4{m-SCHÄC(Ph)C(O)}(m-dppm)]
/
/
Graeme Hogarth *, Matthew O’Brien, Derek A. Tocher
Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
Received 13 January 2003; received in revised form 12 February 2003; accepted 12 February 2003
Abstract
Reaction of [Fe2(CO)6{m-OÄ
complex [Fe2(CO)4(m-HCÄCHPh)(m-SC6F5)(m-dppm)] together with the novel complexes [Fe2(CO)4{m-SC(Ph)Ä
[Fe2(CO)4{m-SCHÄC(Ph)C(O)}(m-dppm)] resulting from elimination of pentafluorobenzene. Both have been characterised
crystallographically, the hydrocarbyl units acting as six-electron donors. The thioalkyne complex [Fe2(CO)4{m-SC(Ph)ÄCH}(m-
/
CÁ
/
C(Ph)Ä
/
CH2}(SC6F5)] with bis(diphenylphosphino)methane (dppm) at 110 8C affords the alkenyl
/
/
CH}(m-dppm)] and
/
/
dppm)] exists as cis and trans isomers. Both are fluxional and interconvert at higher temperatures as shown by 2D NMR.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Thiocarbonyl; Iron; Pentafluorophenylthiol; Thioalkyne
1. Introduction
To date we have focused exclusively on phosphido-
bridge stabilised diiron alkenyl complexes, primary since
they are stable and the phosphorus nucleus provides a
useful NMR handle. In contrast, Seyferth [4,5] and co-
workers [6] have been concerned with related thiolate-
bridged diiron complexes. In general the two types of
complex seem to behave in a similar manner with the
phosphido-bridge analogues having enhanced stability.
We have recently been interested in determining whether
a-b alkenyl isomerisation at a dinuclear centre is a
general process and the thiolate-bridged diiron com-
plexes were chosen as a starting point. The full results of
this work [7] will be reported elsewhere, but here we
detail some unusual findings when we used pentafluor-
othiophenol in order to probe the effect of an electron-
withdrawing group at sulfur. This gave rise to some
quite different chemistry, culminating in the facile
elimination of pentafluorobenzene and leading to the
preparation of unusual thiocarbyl units.
Since the first reported synthesis and characterisation
of s-p alkenyl complexes by Stone and co-workers in
1961 [1], this class of compound has undergone ex-
tensive study. Our interest in this area is twofold.
Firstly, we have shown that the activation barrier to
the well-known ‘windshield wiper’ fluxionality depends
significantly upon the position of substituents on the
alkenyl moiety, with unsubstituted and a-substituted
alkenyls showing high activation barriers, while b-
substitution leads to a significant reduction [2]. Sec-
ondly, we have recently discovered the novel a-b
isomerisation of monosubstituted alkenyl complexes at
a diiron centre [3].
2. Results and discussion
* Corresponding author. Tel.: ꢀ
679-4603.
E-mail address: g.hogarth@ucl.ac.uk (G. Hogarth).
/
44-207-679-4664; fax: ꢀ44-207-
/
In an attempt to prepare [Fe2(CO)6(m-PhCÄ
/
CH2)(m-
SC6F5)] (1) we carried out the reaction of [Fe2(CO)6(m-
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00135-9

G. Hogarth et al. / Journal of Organometallic Chemistry 672 (2003) 22Á
/28
23
SC6F5)(m-CO)][Et3NH] with phenylethyne following
Seyferth’s procedure [4]. Chromatography yielded a
1
dark red oil, shown by H-NMR spectroscopy to be
an inseparable mixture of [Fe2(CO)6(m-PhCÄ
SC6F5)] (1), [Fe2(CO)6(m-HCÄCHPh)(m-SC6F5)] (2) and
CÁC(Ph)ÄCH2}(m-SC6F5)] (3) in an
/
CH2)(m-
/
[Fe2(CO)6{m-OÄ
/
/
/
approximate 7:1:40 ratio. The two alkenyl complexes
1
were identified only on the basis of H-NMR spectro-
scopy, the hydrocarbyl protons appearing in positions
characteristic of a (1, d 3.08, 2.17) and b (2, d 8.62, 4.48,
JHH 14.3 Hz) alkenyl ligands respectively. Formation of
the a,b-unsaturated acyl complex [Fe2(CO)6{m-OÄ
/
CÁ
/
C(Ph)ÄCH2}(m-SC6F5)] (3) as the major reaction pro-
/
duct was unexpected. Seyferth and others have observed
formation of acyl complexes from similar reactions but
generally these lose CO readily to yield alkenyl com-
plexes. The m-SC6F5 group appears to stabilise the acyl
unit and even after reflux in toluene for 4h there was no
evidence of CO loss. Indeed, under these conditions the
small amounts of 1 and 2 disappeared and we were able
to obtain a purer sample of 3. We have noted the
decomposition of other thiolate-bridged alkenyl com-
plexes under similar conditions and conclude that they
are less thermally stable than their phosphido-bridged
analogues. Characterisation of 3 was straightforward,
location of the phenyl group on the b-carbon being
concluded from the observation of singlets at d 7.61 and
6.41 in the 1H-NMR spectrum. In the 19F-NMR
Fig. 1. Molecular structure of cis-[Fe2(CO)4{m-SC(Ph)Ä
/
CH}(m-
˚
dppm)] (5a) with selected bond lengths (A) and angles (8); Fe(1)Á
Fe(2) 2.5129(13), Fe(1)ÁS(1) 2.2544(17), Fe(2)Á
Fe(1)ÁP(1) 2.1927(16), Fe(2)ÁP(2) 2.1927(16), Fe(1)Á
Fe(1)ÁC(7) 2.111(5), Fe(2)ÁC(7) 1.937(7), S(1)ÁC(6) 1.739(6), C(6)Á
C(7) 1.415(8), Fe(1)ÁS(1)ÁFe(2) 67.36(5), Fe(1)ÁC(7)ÁFe(2) 76.6(2),
P(1)ÁFe(1)ÁS(1) 151.13(7), P(2)ÁFe(2)ÁS(1) 153.07(8).
/
/
/S(1) 2.2772(18),
/
/
/
C(6) 2.085(6),
/
/
/
/
/
/
/
/
/
/
/
/
SC6F5)(m-dppm)] (4), [Fe2(CO)4{m-SC(Ph)Ä
/
CH}(m-
dppm)] (5) and [Fe2(CO)4{m-SCHÄC(Ph)C(O)}(m-
/
dppm)] (6), the first two complexes being inseparable.
Further, in the 31P-NMR spectrum it was apparent that
5 consisted of trans (5a) and cis (5b) isomers in an
approximate 2:1 ratio, isomerism relating to the relative
disposition of sulfur and phosphorus atoms. Complexes
5a and 6 were characterised by X-ray crystallography
the results of which are summarised in Figs. 1 and 2,
respectively.
spectrum, three signals assigned to ortho (ꢁ
/
131.6, dt,
J 25.4, 5.6 Hz), meta (ꢁ159.7, m) and para (ꢁ
/
/
148.1, dt,
J 19.8, 2.8 Hz) fluorines were observed. Interestingly, in
the mass spectrum a molecular ion was not observed,
the heaviest ion at m/z 414 corresponding to loss of
pentafluorobenzene.
Heating a toluene solution of 3 and dppm at 110 8C
resulted in a slow reaction over 18 h leading to isolation
Both consist of a diiron centre spanned by a dipho-
sphine and new thiocarbyl groups resulting from the loss
of pentafluorobenzene. In 5, CO has also been lost with
after chromatography of [Fe2(CO)4(m-HCÄ
/
CHPh)(m-
formation of a new sulfurÁcarbon bond to the phenyl-
/

24
G. Hogarth et al. / Journal of Organometallic Chemistry 672 (2003) 22Á28
/
unique proton appearing as a singlet at d 6.91 in the 1H-
NMR spectrum. Complexes 4, 5a and 5b were initially
obtained as a mixture (ca. 1:2:4), although a clean
sample of 5a/5b was obtained after recrystallisation.
Consequently,
[Fe2(CO)4(m-HCÄCHPh)(m-SC6F5)(m-
/
dppm)] 4 was only characterised on the basis of 1H,
19F and 31P-NMR spectra. Given the absence of fluorine
in 5, the presence of a m-SC6F5 ligand in 4 was easily
confirmed by 19F-NMR spectroscopy. Designation as
the b-isomer was made on the basis of the characteristic
positions of the alkenyl protons in the 1H-NMR
spectrum, with further support coming from the rela-
tively low barrier to alkenyl fluxionality (see below)
which we have previously noted for b-alkenyl complexes
[2]. In the context of our previous observations regard-
ing a,b alkenyl isomerisation at the diiron centre [3], it is
noteworthy that the b-alkenyl isomer is produced here
from the a-substituted unsaturated acyl complex 3.
Unfortunately, in the absence of crystallographic data
we cannot discern whether the diphosphine lies trans to
the thiolate or alkenyl bridge. At 213 K, two sharp sets
of doublets are seen in the 31P-NMR spectrum of 5, at
42.4 and 32.7 ppm (JPP 70 Hz) (5a) and 62.8 and 50.3
Fig. 2. Molecular structure of [Fe2(CO)4{m-SCHÄ
/
C(Ph)C(O)}(m-
dppm)] (6) with selected bond lengths (A) and angles (8); Fe(1)Á
Fe(2) 2.6413(5), Fe(1)ÁS(1) 2.2100(8), Fe(2)ÁS(1) 2.2513(8), Fe(1)Á
P(1) 2.2470(8), Fe(2)ÁP(2) 2.2181(8), Fe(1)ÁC(5) 1.964(3), Fe(2)ÁC(6)
2.214(3), Fe(2)ÁC(7) 2.061(3), S(1)ÁC(7) 1.734(3), C(5)ÁC(6) 1.520(4),
C(6)ÁC(7) 1.394(4), C(5)ÁO(5) 1.214(3), Fe(1)ÁS(1)ÁFe(2) 72.60(2),
P(1)ÁFe(1)ÁS(1) 86.81(3), P(2)ÁFe(2)ÁS(1) 97.59(3).
1
ppm (JPP 56 Hz) (5b), while in the H-NMR spectrum
˚
/
(253 K) the unique thiocarbyl protons are observed at d
6.21 (d, J 6.2 Hz) (5a) and 6.13 (t, J 12.8 Hz) (5b). The
larger coupling to phosphorus in the latter suggests that
the unique proton lies trans to the diphosphine and
assignment of isomers in solution is made on this basis.
A number of reports have previously appeared on
diiron thioalkyne complexes. Schrauzer and co-workers
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
substituted carbon, while in 6, CO is retained and the
new carbonÁsulfur bond is to the unsubstituted carbon
centre. In both complexes sulfur bridges the diiron
/
[8] prepared [Fe2(CO)6{m-SC(R)Ä
/
CR}] (RꢂH, Ph)
/
from the reaction of iron carbonyls with 1,2,3-thiadia-
zoles, and Petillon and co-workers [9] synthesised
centre somewhat asymmetrically [5a, Fe(1)Á
/
S(1)
S(1)
˚
2.254(2), Fe(2)Á
2.209(1), Fe(2)Á
carbonÁcarbon double bond binds to a single metal
centre [5a, Fe(1)Á
6, Fe(2)ÁC(6) 2.217(4), Fe(2)Á
the second iron atom is also bound to C(7) [Fe(2)Á
/
S(1) 2.513(1) A; 6, Fe(1)Á
/
[Fe2(CO)6{m-SC(CF3)Ä
/
CCF3}] in 20% yield from the
[(h5-
˚
/
S(1) 2.251(1) A] and the formal
thermal reaction
of Fe3(CO)12 and
/
C5H5)Fe(CO){m-S(Me)C(CF3)C(CF3)}]2. Most perti-
nent to our work is the preparation of [Fe2(CO)6{m-
˚
C(7) 2.111(5) A;
/
C(6) 2.085(6), Fe(1)Á
C(7) 2.069(4) A]. In 5a,
C(7)
/
˚
/
/
SC(Ph)Ä
/
CH}] by Huttner and co-workers [10] from the
reaction of Fe3(CO)12 with tBuSH and PhC2H at 75 8C.
This is the parent of 5 and the unique proton appears at
d 7.60. A number of crystallographic studies have been
/
˚
2.111(5) A] which can be considered as a functionalised
m-alkylidene, while in 6 the carbonyl is retained but is
now bound only through the carbon atom [Fe(1)ÁC(5)
/
reported on related diiron thioalkyne complexes [8Á13],
/
˚
1.971(5) A]. Both new hydrocarbyl ligands are six-
electron donors thus bringing the EAN to the expected
34-electron count. A clear difference between the two
complexes is the relative orientation of sulfur and
phosphorus centres, being approximately trans in 5a
and cis in 6. Further, on the basis of spectroscopic data
and the fluxional behaviour of isomers 5a and 5b, we
assign the latter as containing a cis disposition of sulfur
and phosphorus atoms.
general features being similar to those in 5a. Thioacyl
complexes akin to 6 are also known. Huttner and co-
workers [13] found that reduction of [Fe2(CO)6{m-
SC(Ph)Ä
tBuLi followed by oxidation by iodine afforded
[Fe2(CO)6{m-SC(Ph)ÄCHC(O)}] in 19% yield. Interest-
ing, the latter loses CO rapidly and quantitatively at
70 8C to regenerate [Fe2(CO)6{m-SC(Ph)ÄCH}].
Further, Pe´tillon and co-workers [12] have noted that
reaction of [Fe2(CO)6{m-SC(CF3)ÄCCF3}] with dppm
at 70 8C proceeds via an h1-bonded intermediate to
afford both [Fe2(CO)4{m-SC(CF3)ÄCCF3}(m-dppm)]
and C(CF3)C(O)}(m-dppm)].
[Fe2(CO)4{m-SC(CF3)Ä
/
CH}] by sodium amalgam in the presence of
/
/
Spectroscopic data for 5a and 6 are consistent with
the structures elucidated crystallographically. For 6, two
sharp doublets are seen in the room temperature 31P-
NMR spectrum at 61.3 and 37.9 ppm (JPP 87 Hz), the
/
/
/

G. Hogarth et al. / Journal of Organometallic Chemistry 672 (2003) 22Á
/28
25
Here it was not clarified whether CO loss from the latter
also occurred, although on the basis of Huttner’s results
it appears likely. Huttner and co-workers have crystal-
centres in each isomer via a ‘tethered windshield wiper’
process; and (ii) the interconversion of cis and trans
isomers via a planar hydrocarbyl transition state (Fig.
3). From the coalescence temperature of 308 K we
lographically
CHC(O)}] [13] and structural features are very similar
characterised
[Fe2(CO)6{m-SC(Ph)Ä
/
estimate DG# values of 51.79
/
1 and 52.39
1 kJ molꢁ1
/
to those in 6.
for the tethered ‘windshield wiper’ fluxionality in 5a and
5b, respectively. As they are the same (within error) it
suggests that the relative orientation of the dppm ligand
had little effect. Interestingly, in the X-ray structure of
5a there are two molecules in the asymmetric unit
relating to the two optical isomers of the ‘windshield
wiper’ fluxionality and there are no significant differ-
ences in bond lengths and angles. The second proposed
fluxional process is more unusual. Interconversion of cis
and trans isomers can be envisaged to occur in two
ways; through a planar transition state (shown) or via a
trigonal-twist at both iron centres. While the latter
process is common for monodentate phosphines and
phosphites, as far as we are aware it is unknown for
dppm, probably as a result of the steric strain intro-
duced in a transition-state in which one phosphorus lies
in the plane and the second at right angles to it. Thus we
favour the first option, that is via a planar transition
state. In this process the methylene protons on the
diphosphine would be equivalenced, and this is con-
firmed by 1H-NMR spectroscopy, a sharp methylene
triplet being observed at 373 K. In previous work,
Hickey et al. [11] noted a single room temperature
As previously alluded to, NMR spectra of complexes
4, 5a and 5b were temperature dependent. In order to
probe their fluxionality a number of variable tempera-
ture and 2D-NMR experiments were carried out, 31P-
NMR data proving most informative. At low tempera-
ture (213 K) each appeared as a set of sharp doublets.
Warming to 273 K resulted in the broadening of signals
assigned to 5a and 5b, both coalescing at approximately
308 K. At temperatures higher than 333 K, spectra
become complex but it appeared that signals due to 5a
and 5b coalesced. Interconversion of 5a and 5b was
confirmed by a 2D 31P-NMR spectrum at 283 K, which
showed strong crosspeaks for all four phosphorus
atoms. Signals for 4 remained sharp to 300 K but began
to broaden above this temperature. Unfortunately, due
to the changes occurring with 5a/5b we were unable to
obtain a clear coalescence temperature and can only
estimate a value of 343 K. That the two phosphorus
centres in 4 were equivalencing was confirmed in the 2D
experiment.
Changes to the NMR spectra of 4 are readily
associated with ‘windshield wiper’ alkenyl fluxionality
and the estimated DG# of 58.39
/
1 kJ molꢁ1 compares
carbonyl resonance for [Fe2(CO)6{m-SC(Ph)Ä
/
CPh}],
well with values for related dppm-bridged diiron alkenyl
complexes [2,7]. In order to account for the NMR
properties of 5a and 5b we invoke two fluxional
processes, namely: (i) equivalencing of phosphorus
suggestive of the equivalencing of iron centres and
thus appears that a ‘tethered windshield wiper’ process
may be general in this class of complexes.
Fig. 3. Fluxional processes occurring in thioalkyne complexes: (i) equivalencing of phosphorus centres in each isomer via a ‘tethered windshield
wiper’ process; (ii) the interconversion of cis and trans isomers via a planar hydrocarbyl transition state.

26
G. Hogarth et al. / Journal of Organometallic Chemistry 672 (2003) 22Á28
/
The precise mode of formation of 5a/5b and 6 is
unknown. Given the thermal stability of [Fe2(CO)6{m-
OÄCÁC(Ph)ÄCH2}(SC6F5)] (3) it is clear that dppm
3.2. Synthesis of [Fe2(CO)6{m-OÄ
/
CÁ
/
C(Ph)Ä
/
CH2}(m-
SC6F5)] (3)
/
/
/
To a THF solution (30 cm3) of Fe3(CO)12 (1.52 g, 3.02
mmol) and triethylamine (0.42 cm3, 3.00 mmol), penta-
fluorobenzethiol (0.60 cm3, 3.00 mmol) was added
dropwise by syringe. This led to gas evolution and
heating of the solution. The resulting solution was
stirred for 20 min during which a colour change and
further gas evolution were noted. To this was added
phenylethyne (0.30 cm3, 3.00 mmol). The solution was
stirred at 50 8C for 2 h and turned deep red. Volatiles
were removed under reduced pressure and chromato-
graphy gave a red band eluting with light-petroleum
coordination is a prerequisite for pentafluorobenzene
loss. In related systems, both Pe´tillon and Huttner have
observed evidence of monodentate diphosphine coordi-
nation prior to binding of the second phosphorus centre.
Certainly in 3, the oxygen-bound metal centre should be
the more substitutionally labile leading to a preference
for monodentate coordination. The latter may then
introduce adverse steric effects, however, it is still
difficult to see why pentafluorobenzene loss would be
facile when the proton associated with it lies on a carbon
so distant from the binuclear centre. This may be
circumvented by coordination of the olefinic bond to
the metal centre, and indeed we have recently observed
such five-electron a-b unsaturated acyl complexes at the
phosphido-bridge stabilised diiron centre [14]. Here,
(40Á
30%). NMR spectra revealed trace impurities of
[Fe2(CO)6(m-PhCÄCH2)(m-SC6F5)] (1) and [Fe2(CO)6-
(m-HCÄCHPh)(m-SC6F5)] (2). Heating a toluene solu-
/
60 8C) which afforded 3 as a red oil (0.55 g, ca.
/
/
tion of this mixture (ratio 3:1:2 ca. 40:7:1) for 2 h
resulted in the disappearance of 1 and 2 (as shown by
1H-NMR spectroscopy).
coordination of the carbonÁ
also found to lead to the twisting of the CÁ
of the plane of the metalÁmetal bond with a lengthening
of the FeÁO bond. After elimination of pentafluoro-
/carbon double bond was
/
O vector out
/
3: n(CO)(C6H14) 2079vs, 2040vs, 2004vs, 1987m
/
1
cmꢁ1; H(CDCl3) d 7.61 (s, 1H, CÄ
/
CH2), 7.5Á
CH2); 19F(CDCl3) ꢁ
131.6 (dt,
148.1 (dt, J 19.8, 2.8 Hz, para),
/
7.1 (m,
benzene the sulfido-bridge generated could attack either
the substituted or non-substituted hydrocarbyl centre
leading to 5a/5b (after CO loss) or 6, respectively. Why
CO loss upon attack at the unsubstituted centre should
be so much slower than at the substituted centre remains
unknown, however, heating 6 at 110 8C for 18 h resulted
in no significant change.
5H, Ph), 6.41 (s, 1H, CÄ
J 25.4, 5.6 Hz, ortho), ꢁ
/
/
/
ꢁ
/
159.7 (m, meta); mass spectrum (FAB) m/z 414 [Mꢁ
/
C6F5H], 386, 358, 304. 1: 1H(CDCl3) d 3.08 (s, CÄ
/
CH2),
1
CH2); 2: H(CDCl3) d 8.62 (d, J 14.3 Hz,
2.17 (s, CÄ
CH), 4.47 (d, J 14.3 Hz, CHPh).
/
3.3. Reaction of 3 with bis(diphenylphosphino)methane
(dppm)
A toluene solution (80 cm3) of 3 (0.20 g, 0.33 mmol)
and dppm (0.15 g, 0.39 mmol) was heated at reflux for
18 h. Volatiles were removed under reduced pressure
and chromatography was carried out. A red band
eluting with light-petroleum: dichloromethane (4:1)
afforded an inseparable mixture (ratio 4:5a:5b ca.
3. Experimental
3.1. General
All reactions were carried out under nitrogen using
standard vacuum line techniques and dried and degassed
solvents. Chromatography was carried out on deacti-
vated alumina (6% w/w distilled water) wet packed with
light-petroleum unless otherwise stated. The solution to
1:2:4) of [Fe2(CO)4(m-HCÄ
/
CHPh)(m-SC6F5)(m-dppm)]
(4) and [Fe2(CO)4{m-SC(Ph)Ä
/
CH}(m-dppm)] (5aÁb) as
/
a red powder (0.12 g, ca. 49.%). A second red band
eluting with light-petroleum: dichloromethane (7:3)
afforded [Fe2(CO)4{m-SCHÄC(Ph)C(O)}(m-dppm)] (6)
/
be separated was added to alumina (3Á5 g) and the
/
as a red powder (0.05 g, 20%). Crystals of 5 and 6
suitable for X-ray crystallography were grown by slow
diffusion of methanol into a saturated dichloromethane
solvent removed under reduced pressure. The resulting
solids were then deposited on top of the prepared
column and separation effected by elution with progres-
sively more polar solvents. IR spectra were recorded on
a Nicolet 205 FTIR spectrometer. NMR spectra were
recorded on Bruker AMX400 and Avance500 spectro-
meters and internally referenced to residual solvent
peaks (1H, 13C) or externally to P(OMe)3 (31P) or
CFCl3 (19F). Mass spectra were recorded on VG 7070
high resolution and VG Analytical ZAB2F spectro-
meters and elemental analyses were performed in house.
solution.
1
4: H(CDCl3) (253 K) d 7.8Á
/6.9 (m, Ph), 6.21 (dd, J
9.9, 1.6 Hz, 1H, CH), ca.4.41 (obscured 1H, PCH2P), ca.
3.75 (obscured, 1H, PCH2P), 1.54 (m, 1H, CÄ
/
CHPh);
1H(C7D8)(383K) d 4.03 (dt, J 13.4, 10.2 Hz, 1H, CH2),
3.75 (q, J 10.2 Hz, 1H, CH2) other signals obscured;
19F(CDCl3) ꢁ
/
126.7 (ddd, J 142.9, 16.9, 2.8 Hz, ortho),
155.9 (t, J 22.6 Hz, para), ꢁ162.8 (m, meta);
31P(CDCl3) (213 K) 46.2 (d, J 72 Hz), 35.5 (d, J 72 Hz).
ꢁ
/
/

G. Hogarth et al. / Journal of Organometallic Chemistry 672 (2003) 22Á
/28
27
5: n(CO)(C6H14) 2002s, 1969vs, 1947m, 1918w cmꢁ1
mass spectrum (FAB) m/z 742 [M], 715 [MꢁCO], 686
[Mꢁ2CO], 658 [Mꢁ3CO], 630 [Mꢁ4CO], 528 [Mꢁ
4COÁPhCÄCH2]; Anal. Calc. for Fe2C37H28O4P2-
;
8679 unique [Rint
[I ꢀ2.0s(I)]. At final convergence, R1ꢂ
0.1052 [I ꢀ2.0s(I)] and R1ꢂ0.0752, wR2ꢂ
ꢂ
/
0.0379] of which 5971 were observed
0.0451, wR2ꢂ
0.1179 (all
/
/
/
/
/
/
/
/
/
/
/
/
/
data), for 489 parameters.
S.C6H14: C, 59.87; H, 3.80. Found C, 60.16; H, 3.21%.
1H(C7D8) (383 K) d 3.80 (t, J 10.2 Hz, 2H, CH2); 5a:
1H(CDCl3) (253 K) d 7.8Á
/6.9 (m, Ph), 6.79 (d, J 6.8 Hz,
4. Supplementary material
1H, CH), 4.41 (dt, J 13.3, 9.7 Hz, 1H, PCH2P), 3.80 (dt,
J 13.8, 10.4 Hz, 1H, PCH2P); 31P(CDCl3) (213 K) 42.4
(d, J 70 Hz), 32.7 (d, J 70 Hz); 5b: 1H(CDCl3) (253 K) d
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 200679 and 200678 for 5a and
6, respectively. Copies of this information may be
obtained free of charge from The Director, CCDC, 12
7.8Á6.9 (m, Ph), 6.13 (t, J 12.8 Hz, 1H, CH), 4.13 (dt, J
/
14.2 Hz, 10.9, 1H, PCH2P), 3.28 (dt, J 14.3, 10.8 Hz,
1H, PCH2P); 31P(CDCl3) (213 K) 62.8 (d, J 56 Hz), 50.3
(d, J 56 Hz).
Union Road, Cambridge CB2 1EZ, UK (Fax: ꢀ44-
/
6: n(CO)(CH2Cl2) 2006s, 1971vs, 1947s, 1923m (KBr)
1
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
1592m (CÄ
/
O) cmꢁ1; H(CDCl3) d 7.68Á
/
7.05 (m, 25H,
Ph), 6.91 (s, 1H, CH), 3.83 (dt, J 14.1, 10.6 Hz, 1H,
PCH2P), 2.75 (dt, J 14.1, 10.6 Hz, 1H, PCH2P);
31P(CDCl3) 61.3 (d, J 87 Hz), 37.9 (d, J 87 Hz); mass
Acknowledgements
spectrum (FAB) m/z 771 [M], 742 [Mꢁ
2CO], 686 [Mꢁ3CO], 659 [Mꢁ4CO], 630 [Mꢁ
528 [Mꢁ5COÁPhCÄCH2]; Anal. Calc. for Fe2-
/
CO], 715 [Mꢁ
/
/
/
/5CO],
We thank Dr Abil E. Aliev for help with the 2D NMR
experiments.
/
/
/
C38H28O5P2S.0.5CH2Cl2: C, 57.21; H, 3.45. Found C,
58.07; H, 4.07%.
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˚
/
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/
0.12ꢃ
/
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/
14.0346(10), cꢂ
/
20.9741(15) A, bꢂ
/
3
˚
/
/
4, F(000)ꢂ1744,
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