Synthesis, structure and dynamics of methoxynaphthalene-substituted phospha-ruthenocenes and -ferrocenes

Article abstract of DOI:10.1039/b418926d

The syntheses of potassium 2-(2′-methoxynaphth-1′-yl)-3,4- dimethyl-5-phenylphospholide 4 and η⁵-pentamethyl- cyclopentadienyl{η⁵-2-(2′-methoxynaphth-1′-yl)-3, 4-dimethyl-5-phenylphospholyl}-ruthenium(II) 5 and -iron(II) 6 are descri

Full text of DOI:10.1039/b418926d

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F U L L P A P E R
Synthesis, structure and dynamics of methoxynaphthalene-
substituted phospha-ruthenocenes and -ferrocenes
Duncan Carmichael,*a Louis Ricard,a Nicolas Seeboth,a John M. Brown,b Timothy D. W.
Claridgeb and Barbara Odell*b
a CNRS UMR 7653, DCPH Ecole Polytechnique, 91128, Palaiseau cedex, France.
E-mail: Duncan.Carmichael@polytechnique.fr.; Fax: Intl + 33 1 69333990; Tel: Intl + 33 1
69334571
b Chemistry Research Laboratory, University of Oxford, Mansfield Road, UK OX1 3TA.
E-mail: Barbara.Odell@chem.ox.ac.uk.; Fax: Intl + 44 1865 285002; Tel: Intl + 44 1865
275620
Received 17th December 2004, Accepted 20th April 2005
First published as an Advance Article on the web 18th May 2005
5
The syntheses of potassium 2-(2ꢀ-methoxynaphth-1ꢀ-yl)-3,4-dimethyl-5-phenylphospholide 4 and g -pentamethyl-
5
cyclopentadienyl{g -2-(2ꢀ-methoxynaphth-1ꢀ-yl)-3,4-dimethyl-5-phenylphospholyl}-ruthenium(II) 5 and -iron(II) 6
are described. The barrier to rotation of the naphthyl group (79 kJ mol−1 and 72 kJ mol−1 in CD2Cl2 respectively)
characterises 5 and 6 as potential ‘tropos’ type ligands. Coordination of 5 to [PtCl2(PEt3)] gives two cis and two trans
complexes [PtCl2(PEt3)5] wherein rotation about the phospholyl–naphthyl vector is slow.
allylic alcohol isomerisations,25,26 and hydrogenations27 and Pd-
Introduction
catalysed allylic alkylations.28,29 They have also proved efficient in
The area of naphthalene-derived ligands is one of the most
racemic Suzuki30 and Miyaura31 cross-coupling chemistry and
vibrant in homogeneous catalysis because of the excellent or-
epoxide ring openings.32,33 For an initial study in this area we
ganisation of space provided by the 2,2ꢀ-substituted binaphthyl
intended to prepare and evaluate the configurational stability
skeleton. In addition to symmetrically substituted O,1 N,2 P3
and coordination chemistry of one of the simpler classes, the
methoxynaphthylphosphametallocenes.
At present, the use of phosphametallocenes as ligands in
etc donor pairs, this framework has provided a very easily
accessible4 and useful second generation of C1-symmetrical lig-
ands exemplified by MOP,5–7 MAP,8–11 NOBINs,12–14 quinap,15,16
catalysis has been restricted almost exclusively to the phos-
etc. (see Fig. 1).17,18 Ferrocene–phosphine based MOPF ligands
phaferrocenes. It has been noted previously34 that variation of
bearing simple non-functionalised naphthalene groups have also
the phosphametallocene metal centre is desirable in allowing a
been shown to possess useful properties, particularly in fast
nuancing of properties which might be advantageous in terms
of catalyst lifetime, sensitivity, enantioselection, etc, but late
Pd-catalysed hydrosilylation reactions.19,20 We were therefore
interested in developing one of the few classes of ligands which
has not so far been elaborated with a naphthalene-derived
transition metal phosphametallocenes where M = Fe can only
be prepared easily and in acceptable yields35 in cases where
skeleton: the phosphametallocenes,21 which themselves have
the phospholide ring bears an electron-withdrawing group34
been shown to be quite versatile ligand platforms, notably in
or is hindered about phosphorus.36–39 The 2-methoxynaphth-
enantioselective Cu-catalysed [3 + 2] cycloadditions,22 Kinugasa
1-yl substituent seemed likely to provide sufficient bulk to
reactions,23 and 1,4 additions to enones24 as well as Rh-based
allow the synthesis of both phospharuthenocene and phos-
phaferrocene relatives of MOP.5–7 This paper describes the
preparation and properties of such complexes, and presents the
dynamics and some preliminary coordination chemistry of a
2-(2ꢀ-methoxynaphth-1ꢀ-yl)-phospharuthenocene.
Results and discussion
Synthetic aspects
The best route to the desired naphthalene-substituted phospho-
lyl ligand seemed to involve the preparation of the unknown
1-(2ꢀ-methoxynaphth-1ꢀ-yl)phosphole 3, whereupon a thermally
driven [1,5] sigmatropic shift-step coupled to a deprotonation40,41
would lead to the new phospholide anion 4. This technology is
straightforward in practical terms and is easily scaled up.
Two routes to the requisite 1-(2ꢀ-methoxynaphth-1ꢀ-yl)phos-
phole derivative 3 were evaluated. Both start from the 2-phenyl-
3,4-dimethylphospholide anion 1,41 which was preferred over
the ubiquitous 3,4-dimethylphospholide21 in this preliminary
study because of its easier large-scale preparation and slightly in-
creased bulk. In the first method (steps i and ii of Scheme 1), the
Fig. 1 Some naphthalene-derived ligands.
T h i s j o u r n a l i s
2-phenyl-3,4-dimethylphospholide was initially oxidised cleanly
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 5
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1
2 1 7 3
©

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investigated by low-temperature X-ray diffraction (Fig. 2). The
phenyl ring lies nearly coplanar with the phospholyl but the
methoxynaphthyl component is oriented almost perpendicularly
to the phospholyl plane {P1–C(4)–C(13)–C(14) −72.9◦} with
the methoxyl group lying exo to the ‘sandwich’ defined by the
complex. The unsubstituted arene ring of the naphthyl group
intercalates cleanly between two methyl groups of the Cp*
ligand, suggesting a degree of hindrance within the structure.
Steric strain within the phospharuthenocene is also apparent
in a tilting of the phospholyl ligand which causes the Ru–
˚
C(4) distance of 2.295(2) A to be much longer than Ru–C(1)
˚
{2.196(2) A}, to a degree which is comparable with that in
the triisopropylsilyl analogue 7.38 Simple rotation about the
C(4)–C(13) bond to make the naphthyl ligand coplanar with
the phospholyl ring whilst holding all other bond lengths and
˚
angles constant brings C(15) to within 2.01 A or O(1) to within
˚
1.64 A of the methyl carbon attached to C(3).
Scheme 1 Reagents and conditions: i: I2 (0.5 eq.) THF, 0 ◦C, 30 min; ii:
I2 (1 eq.) THF, 0 ◦C, 30 min, then 2-methoxynaphth-1-yl magnesium
bromide, −40 ◦C, 2 h; iii: 1-iodo-2-methoxynaphthalene (1.5 eq.),
KOt-Bu (1.2 eq.) diglyme, 110 ◦C, 1.5h; iv: KOt-Bu (1 eq.) diglyme,
140 ◦C, 12 h; v: [RuCp*Cl]4 (0.25 eq.), THF, 30 min; vi: [FeCp*Cl]
(1 eq.), THF, 30 min.
to the diastereomeric 1,1ꢀ-biphosphole 2† using iodine. After
isolation, a second (rather experimentally taxing) oxidation
using a further equivalent of iodine gave the corresponding
1-iodophosphole, which was allowed to react without isola-
tion with the appropriate 2-methoxynaphth-1-yl Grignard or
lithium reagent. The attack of the carbon nucleophile was
complicated by redox reactions and the 1-(2ꢀ-methoxynaphth-
1ꢀ-yl)phosphole 3 was obtained in only moderate yield, con-
taminated with 2 and 1-iodo-2-methoxynaphthalene. Attempts
to prevent the formation of the redox-controlled biphosphole
byproduct 2 through transmetallation of the Grignard reagent
with ZnCl2 proved tedious and this methodology was aban-
doned. A second approach, based upon the formal SN2Ar attack
of the phospholide anion upon either 1-bromo- or 1-iodo-2-
methoxynaphthalene in the presence of potassium tert-butoxide
(step iii of Scheme 1), proved much more satisfactory and,
after chromatography on silica, samples of the bright yellow
relatively air-stable phosphole 3 could be obtained on a ca. 25 g
scale. The synthesis was completed by a 12h thermolysis of 3
with KOt-Bu in diglyme at 140 ◦C which gave crude yields
of 4 in the region of 90% according to 31P NMR. Excessive
reaction times led to demethylation of the anisyl group42,43 and
formation of the corresponding phospholide–naphtholate (vide
infra). Once obtained, the product phospholide was generally
complexed to [RuCp*Cl]4 or ‘[FeCp*Cl]’ in situ with careful
control of stoichiometry to avoid the formation of coordination
complexes through reaction of the desired phosphametallocenes
with excess [MCp*Cl]. This appeared to be a particular problem
in the ruthenium case, where the undesired complexes could be
identified by their chemical shifts between +35 and +50 ppm in
the 31P NMR spectrum. To ensure completion, a slight excess of
phospholide and gentle warming were employed.
Fig. 2 X-Ray crystal structure of 5 showing 30% probability ellipsoids.
Selected bond lengths: Ru(1)–P(1), 2.422(1); Ru(1)–C(1), 2.196(2);
Ru(1)–C(2), 2.175(2); Ru(1)–C(3), 2.225(2); Ru(1)–C(4), 2.295(2);
Ru(1)–C(25), 2.176(2); Ru(1)–C(24), 2.189(2); Ru(1)–C(26), 2.204(2);
Ru(1)–C(27), 2.212(2); Ru(1)–C(28), 2.224(2); P(1)–C(1), 1.796(2);
P(1)–C(4), 1.778(2); C(1)–C(2), 1.434(3); C(2)–C(3), 1.435(3);
˚
C(3)–C(4), 1.427(3); C(1)–C(5), 1.480(3) A. Torsion angles: P1–C(4)–
C(13)–C(14), −72.9; P1–C(4)–C(13)–C(22), +99.9; P1–C(1)–C(5)–C(6),
+22.0; P1–C(1)–C(5)–C(10), −154.2◦.
In an early study aimed at recording the crystal structure
of 6, a crude sample of phospholide solution was prepared
by prolonged basic thermolysis of 3 using a non-optimised
protocol and reacted with [FeCp*(acac)]. Instead of the antic-
ipated 6, crystallisation from dichloromethane–methanol gave
a poor yield of orange crystals which were shown to be the
phosphaferrocene–naphthol 8.
The structure shows the anticipated39 ca. 5% shortening in M–
ligand bond lengths upon passing from ruthenium to iron. In
this case, the naphthyl group again lies almost perpendicular to
the phospholyl plane, but shows a P1–C(4)–C(5)–C(6) torsion
angle of −101.5◦, which brings the oxygen atom quite close
Structural studies of naphthyl-substituted phosphametallocenes
(M = Ru, Fe)
A structural study of the phospharuthenocene 5 was made.
Crystallisation of the mixture obtained from reaction of 4
with [RuCp*Cl]4 was effected from CH2Cl2–EtOH and visual
inspection of the yellow air-stable product indicated the presence
of only one form in the bulk. A suitable monocrystal was
˚
to the Fe centre (3.47 A). The hydroxyl hydrogen atom was
located in the final difference map and is oriented away from
the iron atom, so the naphthyl orientation does not result from
an O–H · · · Fe interaction.44,45 Rotating the C–C bond to allow
maximum coplanarity between the phospholyl and naphthyl
groups gives minimum distances from the C(3) methyl group
˚
˚
of 1.66 A to C(13) and 1.84 A to O(1).
† The two diastereomers could not be separated because of rapid inter-
1
conversion. 300 MHz H EXSY experiments give an estimated energy
NMR studies
barrier for this process of 66 kJ mole−1 at 294 K in deuterodichloro-
methane. This barrier lies close to values previously observed for
pyramidal inversion in other phospholes.73,87–89
A priori, the crystallographic results show that the naphthyl
groups in 5 and 8 adopt orientations which might be favourable
2 1 7 4
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1

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for use in enantioselection.46–48 However, whilst dissolution of
crystalline 5 in dichloromethane at −78 ◦C and measurement at
the same temperature gave a single 31P NMR peak at −25.8 ppm
characteristic of 5a,49 warming to room temperature provoked
the appearance of rotamer 5b (−20.8 ppm). Consistently, addi-
tion of deuterobenzene to the bulk solid employed for the crystal
structure analysis of 5 at room temperature gave a solution
containing two compounds, with repeated crystallisation of the
sample producing no effect on the ratio of 3.58 (5a) : 1 (5b) in
C6D6 at 298 K. Thus, conformers 5a and 5b clearly equilibrate
in solution (see Fig. 3). Analogous results were obtained with
6, but the ratio was found to be 1 (6a) : 2.31 (6b), so that the
favoured solution conformer resembles the crystallographically
determined structure 8 (see Fig. 4).
for 5. A series of two-dimensional 1H EXSY experiments alone
was used for 6 due to lower quality 31P 2D EXSY data.
31P 2D EXSY measurements. These were performed in
CD2Cl2 to maximise the solute concentration. A series of two-
dimensional spectra were collected (Fig. 5) with the exchange
mixing times varied from 0.1 to 1.2 s. Data were analysed
according to the procedure described in detail in refs. 53 and
54 and further exemplified by Willem et al.55 for the extraction
of exchange rate constants. For the short mixing times (tm) used
the initial rate approach is valid and the simple two-spin system
rate constant tends to the differential of Bij with respect to time,
where Bij is the so-called normalised cross-peak volume, that
is, the ratio of the cross- to diagonal-peak volumes (Vij and Vjj
respectively):54
Vij (tm)
Vjj (tm)
t
→0
m
Bij (tm) =
−−−−−−→ kij tm
(1)
The forward and back isomerisation rate constants (kij) were
obtained upon plotting the build-up of cross-peak relative to
diagonal-peak volumes against incremented mixing times over
a sequence of 13 experiments. The rate constants are then
represented as the slopes in the linear build-up regime (Fig. 7).
The first order i to j exchange half-life (t1/2) calculated from
eqn. (2):
Fig. 3 Equilibration of 5a and 5b and 6a and 6b through rotation about
the phospholyl–naphthyl bond.
t1/2ij = ln2/kij
(2)
and rotational barriers DG‡ obtained from a simplified Eyring
equation neglecting correlation time effects (eqn. (3)):
DG‡ = RTln[(kBT)/(kijh)]
(3)
ij
(kB being Boltzmann’s constant) are given in Table 1. The
calculated equilibrium constant Kcalc of 0.25 obtained from the
right hand side of eqn. (4)
[5b]
[5a]
k1
k−1
= K =
(4)
Fig. 4 X Ray crystal structure of 8 showing 20% ellipsoids. Selected
bond lengths: Fe(1)–P(1), 2.2959(6); Fe(1)–C(1), 2.109(2); Fe(1)–C(2),
2.080(2); Fe(1)–C(3), 2.093(2); Fe(1)–C(4), 2.145(2); Fe(1)–C(23),
2.068(3); Fe(1)–C(24), 2.093(2); Fe(1)–C(25), 2.102(2); Fe(1)–C(26),
2.076(3); Fe(1)–C(27), 2.057(3); P(1)–C(1), 1.793(2); P(1)–C(4),
1.771(2); C(1)–C(2), 1.426(3); C(2)–C(3), 1.429(3); C(3)–C(4),
compares well with the experimental value Kexp of 0.23 obtained
from the same sample by integration of the peaks for 5a and 5b.
˚
1.423(3); C(4)–C(5), 1.494(3) A. Torsion angles: P1–C(4)–C(5)–C(6),
−101.5; P1–C(4)–C(5)–C(14) +57.1; P1–C(1)–C(15)–C(20), +27.7;
P1–C(1)–C(15)–C(16), −146.4◦.
The spectra of 5a and 5b were assigned through a combination
of COSY, HMQC and HMBC experiments. Large NOE (nuclear
Overhauser effects) were observed in 1D selective NOESY
experiments50 from the Cp* methyl protons to the methoxyl
group in the minor isomer 5b and from the Cp* methyls
to the characteristically19 high frequency shifted naphthyl 8-
proton in the major isomer 5a. These further confirm that
the crystallographically observed form resembles the preferred
structure in solution. The conformations of the corresponding
phosphaferrocene isomers were deduced from the chemical
shifts of the 8-naphthyl protons, which were very similar
to those of the phospharuthenocenes (Fig. 6, upper). The
equilibrium relating both sets of complexes was probed by
2D and 1D exchange experiments. In principle, a single 2D
exchange spectroscopy (EXSY) experiment using an optimised
mixing time suffices to establish the rotation barrier about the
phospholyl–naphthyl bond,51,52 but a more complete approach
was chosen, wherein methods evaluating the rotation barrier
through both 1H and 31P EXSY measurements‡ were compared
Fig. 5 A typical example of a 2D 31P EXSY spectrum of 5 in CD2Cl2.
Technical data: Bruker AMX 500, SF = 202.395 MHz, NS = 8, NE =
64, mixing time = 1.2 s, total recycling time 1 s, total acquisition time
for each entire 2D spectrum ca. 2 h.
‡ In principle, the 1H EXSY experiment may suffer from interference
from NOESY effects. The very similar values obtained here through the
two measurements imply that the NOE influence is negligible.
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1
2 1 7 5

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Table 1 31P 2D EXSY-derived rate constants and energy barriers for
rotation about the phospholyl–naphthalene bond in 5 (at 298 K, in
CD2Cl2)
Table 2 1H 1D EXSY derived rate constants and energy barriers for
rotation about the phospholyl–naphthalene bonds in 5 and 6
T/K
k (C6D6)
102k/s−1
DG‡/kJ mol−1
102k/s−1
DG‡/kJ mol−1
298
298
295
295
k1: 5a → 5b
k−1: 5b → 5a
k1: 6a → 6b
k−1: 6b → 6a
2.6 0.1
9.8 0.2
82.0 0.1
78.7 0.05
71.8 0.1
74.0 0.1
k1: 5a → 5b
k−1: 5b → 5a
4.5 0.6
80.7 0.4
77.2 0.4
18
2
119
48
1
3
1
Fig. 8 Magnetisation transfer observed by 1D H EXSY upon inver-
sion of the naphthyl 8-proton in phospharuthenocenes 5 (×: inversion
of 5b, ꢁ: inversion of 5a).
The calculated rate constants and rotational barriers (Table 2;
derived as above), are comparable with those obtained in the first
experiment, although the rate constants differ by a factor of ca.
2. This may be attributed to the different solvents employed for
the 31P (CD2Cl2) and 1H (C6D6) experiments, as described above.
The Kcalc = 0.27 and the Kexp = 0.28 equilibrium constants again
show good agreement. For 6, exchange between the methoxy
signals gave a slightly poorer quality 2D EXSY data set from
which somewhat lower rotation barriers could be demonstrated
(Table 2).
Fig. 6 Upper: 1H spectrum showing the two conformers of phos-
pharuthenocene 5 in C6D6. Lower: stacked plots showing magnetisation
transfer upon selective inversion at 8.1 ppm of the naphthyl 8-proton of
the minor conformer 5b. Mixing times increase from 100 ms to 1.2 s in
100 ms increments (except for the last, at 200 ms) from back to front.
The barriers in 5 and 6 of ca. 80 and 72 kJ mol−1 respectively
(equating to a rotational half life of approximately 12 s (for 5)
and 1 s (for 6) at 298 K) are significantly below the value for
the configurationally labile biphep (ca. 92 kJ mol−1 at 398 K)57
and much smaller than in genuine atropomeric ligands such as
e.g. 1,1ꢀ-binaphthyl (100 kJ mol−1 at 373 K)58,59 and BINOL (ca.
156 kJ mol−1 at 398 K).60
Coordination chemistry at [PtCl2(PEt3)] centres
Ligands having rapidly interconverting structures in the free
state, such as biphep,57 nuphos61 etc. are increasingly recog-
nised as offering useful and highly stable ligand geometries
after coordination-resolution at a metal centre.62,63 Platinum is
frequently employed because, in addition to binding strongly
to phosphorus donors, resolved Pt(II) complexes of such ‘tro-
pos’ ligands have been shown to be efficient catalysts for
enantioselective cycloadditions.61,64,65 It therefore seemed use-
ful to evaluate the configurational stability of a coordinated
phospharuthenocene–naphthalene ligand and reaction at a
Pt(II) centre was effected. The system resulting from the addition
of 5 to [PtCl2(PEt3)]2 (see Fig. 9), was chosen to facilitate analysis
of the product mixture by NMR measurements.§ Upon reaction
in C6D6, two products were formed instantaneously in a 1 : 0.58
ratio. These were identifiable as trans-configured complexes on
the basis of their large 2JPP and relatively small 1JPtP values,66 with
the predominant product being structure 10 as shown by the
Fig. 7 Normalised cross-peak build-up curves obtained from the 2D
31P EXSY experiments on a deuterodichloromethane solution of 5. ꢀ:
site exchange from 5b, ꢁ: site exchange from 5a.
1H measurements. The 31P determinations for 5 were comple-
mented by twenty-two 1-dimensional 1H EXSY spectra for 5 and
1
seven 2-dimensional H EXSY spectra for 6. C6D6 was chosen
as the solvent in both cases to maximise the 1H NMR chemical
shift dispersion. It provided a particularly marked separation of
the naphthyl 8-proton resonances in the two rotamers (Fig. 6).
For the 1-dimensional EXSY experiments on 5, 1D double
pulsed field gradient spin-echo techniques50,56 were employed to
invert the naphthyl 8-protons which were used as the source
for the magnetisation transfer process. Two separate sets of
11 spectra with mixing times from 0.1 to 1.2 seconds were
recorded with selective inversion of the naphthyl 8-proton in
both the major and minor conformers. Data were analysed using
the initial rate method referenced above with the normalised
exchange peak area calculated as the area ratio between the
exchange peak itself and the selectively inverted peak (Fig. 8).
§ Complexation to the more conventional [PtCl2(PhCN)2] gave much
more complex spectra which presumably result from the presence of
multiple diastereomers. This system was not investigated in detail.
2 1 7 6
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1

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˚
orbital is observed (Pt–O = 5.27 A) and it seems likely that the
rigidity of 12 results purely from increased hindrance within the
ensemble.
Conclusions
The preparation of 2-naphthyl-substituted phospholide anions
is straightforward and these precursors are bulky enough to
allow the synthesis of transition metal phosphametallocenes
other than those containing iron. As anticipated, the phos-
pharuthenocene complex 5 proved easier to handle than its
phosphaferrocene analogues 6 and 8. The 2-(2-methoxynaphth-
1-yl) substituent is unusual because, with the exception of
Hayashi and Ogasawara’s elegant but difficultly-accessible73
menthyl-substituted system,74 the phospholides which have
been used to prepare phospharuthenocenes to date have either
required further elaboration (from esters,34 silanes38) to provide
ligands having useful functionality or are essentially impossible
to modify further (bearing tert-butyl,75 cyclohexyl39 groups, etc.).
The simple 2-methoxynaphth-1-yl substituent employed here
is not sufficiently bulky to allow the resolution of atropomers
of either the phospharuthenocene or -ferrocene complexes but
the relatively high rotation barriers mean that a further small
increase in hindrance will probably suffice to block rotation
about the phospholyl–naphthalene bond. That the rotation
barrier is higher for 5 than 6 implies that the latter’s more tightly
packed coordination sphere does not have a significant impact
upon the rotation of the naphthyl ring, probably because of the
rather soft potential surface for ring bending in metallocenes.76,77
Thus any hindrance introduced to block a configuration will
probably function better when located at an appropriate site
within the naphthylphospholyl ligand than when incorporated
into the Cp*.
The configurational stability of the coordinated
phosphametallocene–naphthalene ligand is quite high when
bound to the reasonably inert transition metal centre 12. The
data available at this stage do not preclude an ‘on-metal’
equilibration mechanism for the interconversion of 11 and
12,78,79 but the relative weakness of the Pt–phosphametallocene
bond80 leads us to speculate that a dissociation–rotation–
recombination mechanism may be more likely. Such a pathway
should be inhibited should a coordinating group replace
the OMe substituent. Methods for preparing enantiopure
derivatives of 5 and related ligands are under investigation.
Fig. 9 Phospharuthenocene complexes formed through upon interac-
tion of 5 with [PtCl2(PEt3)]2.
characteristic19 high frequency shift of the naphthyl 8-proton.
The mixture evolved in CDCl3 in the absence of further ligand
and, after standing for two weeks, ca. 80% of the spectrum
integral comprised resonances attributable to the cis-complexes
11 and 12. No EXSY evidence for exchange between any of
the possible pairs of complexes 9 to 12 was obtained and it
is clear that interconversion between the various complexes is
1
slow. H NMR data indicate that the major cis-diastereomer
in solution after long standing is 12 and crystallisation of the
mixture by diffusion of ethanol into the chloroform solution
gave a clean sample of this complex. Upon redissolution of the
crystals, the spectrum showed clean 12, with a return to the
previously observed equilibrium mixture of 11 and 12 occurring
only over a week.
To probe the loss of rotational freedom about the phospholyl–
naphthalene vector associated with the coordination to Pt, a
structural determination of 12 was undertaken (see Fig. 10). The
˚
complex shows an expectedly short Pt(1)–P(1) bond 2.210(2)A,
which results from the high s-character in the phosphamet-
allocene donor hybrid, and a short Pt(1)–Cl(2) separation of
˚
2.344(2)A as a consequence of its correspondingly weak trans
influence.67–69 As anticipated, the methoxyl group lies exo to
the phosphametallocene sandwich but is oriented away from
platinum centre by a P1–C(1)–C(5)–C(14) torsion angle of
−118.9◦. Thus, as in structures containing the MOP ligand,70–72
no interaction between the MeO group and the empty metal dz2
Experimental
All operations were performed either using cannula tech-
niques on Schlenk lines under an atmosphere of dry nitro-
gen or in a Braun Labmaster 130 drybox under dry puri-
fied argon. Column chromatography was performed on 63–
200 lm silica or 50–160 lm neutral alumina as appropriate.
[RuCp*Cl]4,81 ‘[FeCp*Cl]’,24,82,83 [PtCl2(PEt3)]2,84 1-phenyl-3,4-
dimethylphosphole85 and [K(PC4PhMe2H)·diglyme] 186 were
prepared as described previously. Tetrahydrofuran was distilled
from sodium–benzophenone ketyl and pentane from sodium–
benzophenone ketyl–tetraglyme under an atmosphere of dry
˚
nitrogen and stored for short periods over 4 A molecular
sieves. Diglyme was distilled under reduced pressure from CaH2.
Dichloromethane was distilled from P4O10 under nitrogen.
Deuterobenzene was used as received, and deuterochloroform
was deacidified through alumina prior to use. NMR measure-
ments were made on Bruker AM 200, Avance 300, AMX500 and
DRX500 spectrometers and are referenced to residual proton
signals (C6D5H or CHCl3) in the deuterated solvents or external
H3PO4 as appropriate. Mass spectra were obtained under 70 eV
electron impact using direct inlet methods on a Hewlett Packard
5989B spectrometer. Combustion analyses were performed by
the ‘Service de microanalyse du CNRS’, Gif sur Yvette, France.
Fig. 10 X Ray crystal structure of 12 showing 20% probability
ellipsoids. Selected bond lengths: Pt(1)–P(1), 2.210(2); Pt(1)–P(2),
2.242(3); Pt(1)–Cl(1), 2.374(2); Pt(1)–Cl(2), 2.344(2); Ru(1)–P(1),
2.313(2); Ru(1)–C(1), 2.300(8); Ru(1)–C(2), 2.215(8); Ru(1)–C(3),
2.192(8); Ru(1)–C(4), 2.228(8); Ru(1)–C(24), 2.21(1); Ru(1)–C(25),
2.24(1); Ru(1)–C(26), 2.21(1); Ru(1)–C(27), 2.185(8); Ru(1)–C(28),
2.18(1); P(1)–C(1), 1.782(8); P(1)–C(4), 1.775(8); C(1)–C(2), 1.41(1);
˚
C(2)–C(3), 1.44(1); C(3)–C(4), 1.42(1); C(1)–C(5), 1.48(1) A. Tor-
sion angles: P1–C(1)–C(5)–C(6), +57.1; P1–C(1)–C(5)–C(14), −118.9;
P1–C(4)–C(18)–C(23), +137.9; P1–C(4)–C(18)–C(19), −40.8◦.
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1
2 1 7 7

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2,2ꢀ-Diphenyl-3,3ꢀ,4,4ꢀ-tetramethyl-1,1ꢀ-biphospholes 2
4.6 Hz, 1H, 3-Np), 3.36 (s, 3H, MeO), 2.07 (d, JPH = 4.8 Hz, 3H,
MeCCH), 2.01 (dd, JHH = 1.1 Hz, JPH = 5.0 Hz, 3H, MeCCPh).
13C (C6D6): d 163.5 (d, J = 14.9 Hz, 2-napthyl), 149.2 (PCPh),
147.5 (d, J = 12.7 Hz, PCC); 140.5 (d, J = 19.5 Hz, PCC), 139.7
(d, J = 2.2 Hz, 8a-Np), 139.2 (d, J = 17.5 Hz, ipso-Ph), 134.0
(4-Np), 130.2 (d, J = 2.1 Hz, 4a-Np), 129.9 (d, J = 9.0 Hz, o-Ph),
129.1 (5-Np), 128.9 (m-Ph),128.5 (PCH), 127.8 (7-Np), 126.8 (d,
J = 10.3 Hz, 8-Np), 126.7 (p-Ph), 124.5 (6-Np), 114.5 (d, J =
3.8 Hz, 3-Np), 112.2 (d, J = 15.7 Hz, 1-Np), 57.3 (CH3O), 19.2
(d, J = 3.2 Hz, CH3CCH), 15.4 (d, J = 1.7 Hz, CH3CCPh). MS
(CI{NH3} m/z, %) 344 ([M]+, 100%).
Method 1. A THF (45 mL) solution of I2 (1.77 g, 6.95 mmol)
was added dropwise at −78 ◦C to a THF (10 mL) solution
of potassium 2-phenyl-3,4-dimethylphospholide–diglyme (5.0 g,
13.9 mmol). A color change from pale to intense yellow was
observed and a white precipitate was formed. The mixture was
evaporated to dryness under reduced pressure and purified by
flash chromatography on degassed silica (pentane–toluene 85
: 15). The mixture of equilibrating 1,1ꢀ-biphospholes 2 was
obtained as a yellow solid (571 mg, 22%).
Method 2. Solid PbCl2 (2.78 g, 10 mmol) was added
to a THF (10 mL) solution of potassium 2-phenyl-3,4-
dimethylphospholide–diglyme (7.15 g, 19.9 mmol) causing an
immediate colour change from light yellow to intense red. The
solution was then heated for 30 min at 45 ◦C. A dense grey
precipitate was separated from the yellow solution and the
solvent was removed. Flash chromatography on degassed silica
(pentane–toluene 85 : 15) afforded the 1,1ꢀ-biphospholes 2 as a
yellow solid (1.61 g, 22%). Major diastereoisomer (203 K). 31P
Potassium 2-(2ꢀ-methoxynaphth-1ꢀ-yl)-3,4-dimethyl-5-phenyl-
phospholide–diglyme 4
A
mixture of 1-(2ꢀ-methoxynaphth-1ꢀ-yl)-2-phenyl-3,4-
dimethylphosphole 3 (2.00 g, 5.8 mmol) and potassium
tert-butoxide (620 mg, 5.5 mmol) in diglyme (45 mL) was
heated at 140 ◦C for 12 hours. After checking complete
conversion to the phospholide by 31P NMR, the diglyme
solvent was evaporated under reduced pressure. The residue
was redissolved in a minimum of toluene (ca. 10 mL) and
precipitated with pentane to afford solid yellow 4 which was
washed several times with pentane. 31P NMR (THF-d8): d 86.7.
1H NMR (THF-d8): d 8.23–8.20 (m, 1H, 8-Np), 7.67–7.64 (m,
1H, 5-Np), 7.64 (d, JHH = 9.0 Hz, 1H, 3-Np), 7.52 (pseudo-d,
JHH = 8.2 Hz, 2H, o-Ph), 7.28 (d, JHH = 9.0 Hz, 1H, 4-Np),
7.22–7.08 (m, 2H, 6 and 7-Np), 7.14 (pseudo-t, JHH = 7.8 Hz,
2H, m-Ph), 6.90 (pseudo-t, JHH = 7.9 Hz, 1H, p-Ph), 3.77 (s,
3H, MeO), 3.49 (m, 4H, diglyme), 3.41 (m, 4H, diglyme), 3.24
(s, 6H, diglyme), 2.34 (s, 3H, PCPhCMe), 1.80 (s, 3H, PCCMe).
13C (C6D6): d 154.3 (d, J = 4.0 Hz, 2-Np), 148.3 (d, J = 39.0 Hz,
PCPh), 146.5 (d, J = 22.1 Hz, ipso-Ph), 139.9 (d, J = 36.7 Hz,
PCNp), 137.2 (d, J = 2.5 Hz, 8a-Np), 130.7 (4a-Np), 130.6
(d, J = 19.5 Hz, 1-Np), 129.8 (8-Np), 129.6 (d, J = 10.0 Hz,
o-Ph), 128.7 (d, J = 11.1 Hz, PCPhCMe), 128.0 (m-Ph), 127.5
(5-Np), 126.5 (4-Np), 125.1 (7-Np), 123.7 (6-Np), 123.7 (d, J =
5.5 Hz, PCNpCMe), 122.8 (p-Ph), 113.8 (3-Np), 72.9 (CH2,
diglyme), 71.3 (CH2, diglyme), 59.13 (CH3, diglyme), 57.0
(CH3O), 16.1(CH3CCPh), 15.4 (CH3CCNp).
1
NMR (CD2Cl2, 203 K): d −20.0. H NMR (CD2Cl2, 203 K):
d 7.35 (pseudo-t, J = 7.2 Hz, 4H, m-Ph), 7.24 (pseudo-t, J =
7.2 Hz, 2H, p-Ph), 6.98 (d, J = 7.1 Hz, 4H, o-Ph), 6.06 (pseudo-
t, J = 20.7 Hz, 2H, PCH), 1.96 (s, 6H, MeCCH), 1.74 (s, 6H,
MeCCPh). 13C (CD2Cl2, 203 K): d 151.4 (br, PCC), 142.9 (br,
PCCPh), 141.9 (pseudo-t, J = 5.3 Hz, PCC), 137.1 (pseudo-t,
J = 8.8 Hz, ipso-Ph), 129.2 (pseudo-t, J = 4.3 Hz, o-Ph), 127.8
(m-Ph), 126.0 (p-Ph), 124.6 (pseudo-t, J = 3.4 Hz, PCH), 18.5
(MeCCH), 14.4 (MeCCPh). Minor diastereoisomer (203 K). 31
P
NMR (CD2Cl2, 203 K): d −28.7. 1H NMR (CD2Cl2, 203 K): d
7.27 (pseudo-t, J = 7.3 Hz, 4H, m-Ph), 7.14 (t, J = 7.3 Hz, 2H, p-
Ph2), 6.99 (d, J = 7.2 Hz, 4H, o-Ph), 5.91 (pseudo-t, J = 20.7 Hz,
2H, PCH), 1.81 (s, 6H, MeCCPh), 1.35 (s, 6H, MeCCH). 13C
(CD2Cl2, 203 K): d 151.4 (br, PCC), 144.3 (pseudo-t, J = 7.4 Hz,
PCCPh), 140.4 (pseudo-t, J = 3.1 Hz, PCC), 137.0 (pseudo-
t, J = 8.8 Hz, ipso-Ph), 128.9 (pseudo-t, J = 4.8 Hz, o-Ph),
127.5 (m-Ph), 125.7 (p-Ph), 121.3 (br, PCH), 18.2 (CH3CCH),
13.9(CH3CCPh). EI-MS (m/z,%) 374 ([M]+, 100%).
1-(2ꢀ-Methoxynaphth-1ꢀ-yl)-2-phenyl-3,4-dimethylphosphole 3
Method 1. A THF (20 mL) solution of iodine (1.77 g,
6.95 mmol) was added dropwise over 30 min at 0 ◦C to a THF
(25 mL) solution of 2 (5.2 g, 13.9 mmol). The mixture was
stirred for 15 min and subsequently treated dropwise at −40 ◦C
with 2-methoxynaphthylmagnesium bromide (17.0 mmol) in
THF (60 mL) of over a period of 1 hour. After evaporation
to dryness in vacuo, the residue was purified by chromatography
on silica using a solvent gradient rising from pentane : toluene
3 : 2 to pure toluene. After, the sequential addition of 2,2ꢀ-
diphenyl-3,3ꢀ,4,4ꢀ-tetramethyl-1,1ꢀ-biphospholes 2 and 1-iodo-
2-methoxynaphthalene, the product was recovered as a bright
yellow solid. Yield 2.01 g, (21%).
g5-Pentamethylcyclopentadienyl{g5-2-(2ꢀ-methoxynaphth-1ꢀ-
yl)-3,4-dimethyl-5-phenylphospholyl}ruthenium(II) 5
A room temperature THF (100 mL) solution of [RuCp*Cl]4
(1.20 mg, 1.10 mmol) was added to a THF (100 mL) solution
of 4 (4.40 mmol) and the orange mixture was stirred for 30 min.
After refluxing for a further 30 min, the mixture was evaporated
to dryness in vacuo and purified by flash chromatography
in pure toluene on silica. Crystallisation of the crude from
dichloromethane–ethanol gave pale yellow essentially air-stable
crystals of the product 5 (2.20 g, 86%). Ratio: 0.31 (5b) : 1 (5a)
in C6D6 at 298 K. Major (5a): 31P NMR (CDCl3): d −24.8.
1H NMR (C6D6): d 9.86 (d, JHH = 8.5 Hz, 1H, 8-Np), 7.71 (d,
JHH = 8.1 Hz, 1H, 5-Np), 7.59 (ddd, JHH = 8.3 Hz, JHH = 6.8 Hz,
JHH = 1.3 Hz, 1H, 7-Np), 7.57 (d, JHH = 9.1 Hz, 1H, 4-Np), 7.42
(pseudo-d, JHH = 7.3 Hz, 2H, o-Ph), 7.33 (ddd, JHH = 7.9 Hz,
Method 2. A diglyme (20 mL) solution of potassium 2-
phenyl-3,4-dimethylphospholide–diglyme 1 (5.0 g, 13.9 mmol),
1-iodo-2-methoxynaphthalene (4.74 g, 16.7 mmol) and potas-
sium tert-butoxide (1.87 g, 16.7 mmol) was heated to 110 ◦C
for 90 min. After cooling, evaporation to dryness under reduced
pressure and extraction with toluene (40 mL), purification by
flash chromatography on silica gel (pentane–toluene 4 : 1) gave
yellow crystalline phosphole 3. Yield 2.33 g (41%). Found C,
80.20; H, 6.09; P, 8.88. Calc. for C23H21OP C, 80.21; H, 6.15; P,
8.99%. 31P NMR (C6D6): d −12.9. 1H NMR (C6D6): d 7.98 (d,
JHH = 8.6 Hz, 1H, 8-Np), 7.53 (ddd, JHH = 8.3 Hz, JHH = 1.2 Hz,
JPH = 2.2 Hz, 2H, o-Ph), 7.42 (d, JHH = 8.1 Hz, 1H, 5-Np), 7.38
JHH = 6.9 Hz, JPH = 1.0 Hz, 1H, 6-Np), 7.15 (pseudo-t, JHH
=
7.9 Hz, 2H, m-Ph), 7.03 (tt, JHH = 7.3 Hz, JHH = 1.1 Hz, 1H,
p-Ph), 6.95 (d, JHH = 9.1 Hz, 1H,3-Np), 3.35 (s, 3H, MeO),
2.12 (s, 3H, MeCCPh), 2.02 (s, 3H, MeCCNp), 1.57 (s, 15H,
Cp*). 13C NMR (C6D6): 155.5 (d, J = 2.5 Hz, 2-Np), 140.5 (d,
J = 17.5 Hz, ipso-Ph), 133.1 (8a-Np), 130.5 (4a-Np), 130.1 (d,
J = 7.6 Hz, o-Ph), 128.9–127.8 (m-Ph, 4,5 and 8-Np), 126.0
(p-Ph), 125.5 (7-Np), 124.2 (6-Np), 122.2 (d, J = 14.0 Hz, 1-
Np), 115.2 (3-Np), 102.6 (d, J = 59.2 Hz, PCPh), 98.3 (d, J =
60.6 Hz, PCNp), 96.5 (d, J = 3.5 Hz, PCCMe), 90.8 (d, J =
3.7 Hz, PCCMe), 88.9 (Cp*), 56.4 (MeO), 15.1 (MeCCNp),
14.4 (MeCCPh), 11.0 (MeCp*). Minor (5b): 31P NMR (CDCl3):
d −19.7. 1H NMR (C6D6): d 8.0 (d, JHH = 8.5 Hz, 1H, 8-
Np), 7.66 (dd, JHH = 7.8 Hz, JHH = 1.3 Hz, 1H, 5-Np), 7.54
(d, JHH = 9.0 Hz, 1H, 4-Np), 7.30 (ddd, JHH = 8.4 Hz, JHH
6.8 Hz, JHH = 1.3 Hz, 1H, 7-Np), 7.06 (ddd, JHH = 8.0 Hz, JHH
=
=
6.9 Hz, JHH = 1.1 Hz, 1H, 6-Np), 7.00 (pseudo-t, JHH = 7.9 Hz,
2H, m-Ph), 6.81 (tt, JHH = 7.4 Hz, JHH = 1.2 Hz, 1H, p-Ph), 6.67
(d, JPH = 38.2 Hz, 1H, PCH), 6.64 (dd, JHH = 9.0 Hz, JPH
=
2 1 7 8
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1

View Article Online
(d, JHH = 8.9 Hz, 1H, 4-Np), 7.54 (pseudo-d, JHH = 8.3 Hz, 2H,
o-Ph), 7.25 (ddd, JHH = 8.3 Hz, JHH = 6.8 Hz, JHH = 1.5 Hz, 1H,
7-Np), 7.201 (ddd, JHH = 8.1 Hz, JHH = 6.7 Hz, JPH = 1.4 Hz,
1H, 6-Np), 7.195 (pseudo-t, JHH = 8.1 Hz, 2H, m-Ph), 7.0 (tt,
JHH = 7.4 Hz, JHH = 1.0 Hz, 1H, p-Ph), 6.94 (d, JHH = 8.9 Hz,
1H, 3-Np), 3.58 (s, 3H, MeO), 2.08 (s, 3H, PCPhCMe), 1.70 (s,
3H, PCNpCMe), 1.62 (s, 15H, Cp*). 13C NMR (C6D6): d 154.6
(2-Np), 140.7 (d, J = 17.8 Hz, ipso-Ph), 134.7 (8a-Np), 130.4 (4a-
Np), 130.3 (d, J = 7.7 Hz, o-Ph), 128.9–127.8 (m-Ph, 4,5 and
8 Np), 126.0 (p-Ph), 126.0 (7-Np), 124.0 (6-Np), 123.4 (d, J =
12.8 Hz, 1-Np), 116.3 (3-Np), 102.4 (d, J = 59.5 Hz, PCPh), 97.9
(d, J = 61.5 Hz, PCNp), 93.5 (d, J = 3.9 Hz, PCCMe), 90.5 (d,
J = 2.7 Hz, PCCMe), 88.6 (Cp*), 58.5 (MeO), 16.8 (MeCCNp),
14.1 (MeCCPh), 10.9 (MeCp*). MS (CI{NH3} m/z, %) 580
([M]+, 45%), 190 (100%).
compound was obtained as deep orange crystals (50 mg, 19%).
Only one rotamer was visible in solution. 31P (C6D6): d −53.3.
1H (CDCl3): d 8.36 (d, JPH = 2.7 Hz, 1H), 7.68 (pseudo-t, JHH
=
8.1 Hz, 2H), 7.56 (pseudo-d, JHH = 8.1, 2H), 7.27–7.17 (m,
7H), 2.53 (s, 3H), 1.76 (s, 3H), 1.66 (s, 15H). 13C (CDCl3): d
149.8 (d, J = 1.6 Hz, 2-Np), 139.9 (d, J = 17 Hz, ipso-Ph),
133.9 (8a-Np), 129.2 (d, J = 11.6 Hz, o-Ph), 129.0 (CH), 128.8
(CH), 128.4 (CH), 128.0 (m-Ph), 126.1 (CH), 125.8 (CH), 125.3
(CH), 122.7 (CH), 117.0 (CH), 114.2 (d, J = 13.1 Hz, 1-Np),
98.5 (d, J = 56.8 Hz, PC), 96.5 (d, J = 3.9 Hz, PCC), 91.4 (d,
J = 55.6 Hz, PC), 91.1 (d, J = 3.7 Hz, PCC), 83.7 (Cp*), 14.9
(MeCCP); 14.2 (MeCCP), 10.1 (Me from Cp*). EI-MS (m/z,
%) 521 ([M]+, 100%)
trans-Dichloro(triethylphosphine)[g5-pentamethylcyclopenta-
dienyl{g5-2-(2ꢀ-methoxynaphth-1ꢀ-yl)-3,4-dimethyl-5-phenyl-
phospholyl}ruthenium(II)]platinum(II) 9 and 10
g5-Pentamethylcyclopentadienyl{g5-2-(2ꢀ-methoxynaphth-1ꢀ-
yl)-3,4-dimethyl-5-phenylphospholyl}iron(II) 6
A THF (50 mL) solution of 4 (4.7 mmol) was added to a THF
(40 mL) solution of freshly prepared ‘[Cp*FeCl]n’ (4.7 mmol),
causing a colour change from bright green to orange. After
checking completion of the reaction by 31P NMR, the solvent
was evaporated in vacuo and the residue was taken up in
toluene (100 mL). After filtration through a pad of Celite, the
orange solution was concentrated to ca. 20 mL and layered with
degassed methanol (50 mL) to give an orange solution. Orange
crystalline 6 was obtained upon standing (1.5 g, 60%). Solution
rotamer ratio: 1 (6b) : 0.42 (6a) in C6D6 at 298 K. Major (6b):
Finely divided [PtCl2(PEt3)]2 (6.6 mg, 8.6 lmol) was added
to a C6D6 (0.4 mL) solution of 5 (10 mg, 0,017 mmol) at
room temperature. The sample was shaken vigorously and the
composition of the yellow solution was investigated in situ by
NMR spectroscopy. A ratio of 0.58 (9) : 1 (10) was observed in
C6D6 at 298 K. 10 (Major): 31P NMR (CDCl3): d 20.52 (JP–Pt
=
2637 Hz, JP–P = 562 Hz); 14.49 (JP–Pt = 2955 Hz, JP–P = 562 Hz).
1H NMR (C6D6): d 9.96 (d, JHH = 8.5 Hz, 1H, 8-Np), 7.85 (ddd,
JHH = 8.2 Hz, JHH = 6.8 Hz, JHH = 1.3 Hz, 1H, 7-Np), 7.73 (d,
JHH = 8.3 Hz, 1H, 5-Np), 7.72 (pseudo-d, JHH = 7.9 Hz, 2H, o-
Ph), 7.60 (d, JHH = 9.0 Hz, 1H, 4-Np), 7.40 (ddd, JHH = 7.4 Hz,
1
31P (C6D6): d −36.4. H NMR (C6D6): d 7.71 (m, 1H, 8-Np),
7.70 (pseudo-d, JHH = 7.7 Hz, 1H, 5-Np), 7.65 (pseudo-t, JHH
=
JHH = 6.9 Hz, JPH = 1.0 Hz, 1H, 6-Np), 7.22 (pseudo-t, JHH =
7.7 Hz, 1H, 7-Np), 7.64 (pseudo-d, JHH = 7.1 Hz, 2H, o-Ph),
7.57 (d, JHH = 9.0 Hz, 1H, 4-Np), 7.36 (ddd, JHH = 7.9 Hz,
7.9 Hz, 2H, m-Ph), 7.04 (pseudo-t, JHH = 7.9 Hz, 1H, p-Ph),
7.02 (d, JHH = 9.0 Hz, 1H, 3-Np), 3.65 (s, 3H, MeO), 2.05 (s, 3H,
MeCCP), 2.04 (s, 3H, MeCCP), 1.71 (s, 15H, Cp*), 1.43 (m, 6H,
CH2), 0.7 (m, 9H, CH3). 9 (Minor): 31P NMR (CDCl3): d 25.9
JHH = 6.9 Hz, JPH = 1.1 Hz, 1H, 6-Np), 7.16 (pseudo-t, JHH
=
7.1 Hz, 2H, m-Ph), 7.06 (pseudo-t, JHH = 7.1 Hz, 1H, p-Ph),
6.93 (d, JHH = 9.0 Hz, 1H, 3-Np), 3.62 (s, 3H, MeO), 2.30 (s, 3H,
MeCCP), 1.86 (s, 3H, MeCCP), 1.57 (s, 15H, Cp*). 13C NMR
(C6D6): d 154.2 (2-Np), 141.6 (d, J = 16.9 Hz, ipso-Ph), 135.2
(d, J = 3.4 Hz, 8a-Np), 130.5 (4a-Np), 130.3 (d, J = 11.4 Hz,
o-Ph), 128.9–128.0 (m-Ph, 4-, 5- and 8-Np), 125.9 (p-Ph), 125.8
(7-Np), 123.9 (6-Np), 123.4 (d, J = 13.6 Hz, 1-Np), 115.7 (3-
Np), 98.8 (d, J = 56.9 Hz, PCPh), 96.2 (d, J = 58.7 Hz, PCNp),
93.5 (d, J = 4.9 Hz, PCCMe), 89.3 (d, J = 4.2 Hz, PCCMe),
83.3 (Cp*), 57.8 (MeO), 17.5 (MeCCP), 14.9 (MeCCP), 10.8
(MeCp*). Minor (6a): 31P (C6D6): d −42.8. 1H NMR (C6D6): d
10.1 (d, JHH = 8.5 Hz, 1H, 8-Np), 7.74 (pseudo-d, JHH = 7.5 Hz,
2H, o-Ph), 7.73 (m, 1H, 5-Np), 7.70 (m, 1H, 8-Np), 7.67 (m, 1H,
(JP–Pt = 2689 Hz, JP–P = 572 Hz), 13.24 (JP–Pt = 2931 Hz, JP–P
=
572 Hz). 1H NMR (C6D6): d 8.14 (d, JHH = 7.3 Hz, 1H, 8-Np),
8.10 (pseudo-d, JHH = 8.0 Hz, 2H, o-Ph), 7.60 (d, JHH = 8.0 Hz,
1H, 5-Np), 7.54 (d, JHH = 8.9 Hz, 1H, 4-Np), 7.32 (pseudo-t,
JHH = 7.9 Hz, 2H, m-Ph), 7.29 (pseudo-t, JHH = 7.5 Hz, 1H,
7-Np), 7.16 (pseudo-t, JHH = 8 Hz, 1H, 6-Np), 7.14 (pseudo-t,
JHH = 7.9 Hz, 1H, p-Ph), 7.05 (d, JHH = 8.9 Hz, 1H, 3-Np), 4.26
(s, 3H, MeO), 2.04 (s, 3H, MeCCP), 1.91 (s, 3H, MeCCP), 1.74
(s, 15H, Cp*), 1.25 (m, 6H, CH2), 0.6 (m, 9H, CH3).
cis-Dichloro(triethylphosphine)-g5-[pentamethylcyclopentadienyl-
g5-{2-(2ꢀ-methoxynaphth-1ꢀ-yl)-3,4-dimethyl-5-
7-Np), 7.55 (d, JHH = 8.8 Hz, 1H, 4-Np), 7.21 (pseudo-t, JHH
=
7.5 Hz, 2H, m-Ph), 7.16 (m, 1H, 6-Np), 7.10 (pseudo-t, JHH
=
phenylphospholyl}ruthenium(II)]platinum(II) 11 and 12
7.5 Hz, 1H, p-Ph), 6.95 (d, JHH = 8.8 Hz, 1H, 3-Np), 3.21 (s, 3H,
MeO), 2.35 (s, 3H, MeCCP), 2.17 (s, 3H, MeCCP), 1.51 (s, 15H,
Cp*). 13C NMR (C6D6): d 156.3 (d, J = 2.5 Hz, 2-Np), 141.2
(d, J = 17.2 Hz, ipso-Ph), 132.8 (8a-Np), 130.4 (4a-Np), 130.1
(d, J = 11.6 Hz, o-Ph), 128.9–128.0 (m-Ph, 4-, 5- and 8-Np),
125.8 (p-Ph), 125.1 (7-Np), 124.3 (6-Np), 123.4 (d, J = 13.6 Hz,
1-Np), 117.7 (3-Np), 98.6 (d, J = 56.1 Hz, PCPh), 96.1 (d, J =
4.5 Hz, PCCMe), 95.9 (d, J = 57.2 Hz, PCNp), 89.7 (d, J =
3.6 Hz, PCCMe), 83.9 (Cp*), 56.5 (MeO), 15.8 (MeCCNp), 15.2
(MeCCPh), 11.0 (MeCp*). EI-MS (m/z, %) 534 ([M]+, 100%).
Finely divided [PtCl2(PEt3)]2 (6.6 mg, 8.6 lmol) was added to
a CDCl3 (0.4 mL) solution of 5 (10 mg, 0,017 mmol) and the
initially formed mixture of 9 and 10 was allowed to stand at room
temperature for 15 days, whereupon the combined conversion
into the cis isomers 11 and 12 had reached 78%. Diffusion of
methanol into the solution afforded pure colourless crystals of
12 suitable for X-ray analysis. Redissolution of the crystals gave
only one cis-isomer whose spectrum was identical to the major
isomer originally present in the mixture. 12: 31P NMR(CDCl3):
d 21.82 (JP–Pt = 4552 Hz, JP–P = 24.5 Hz), 12.99 (JP–Pt = 3184 Hz,
1
JP–P = 24.5 Hz). H NMR (CDCl3): d 9.49 (d, JHH = 8.5 Hz,
g5-Pentamethylcyclopentadienyl[g5-2-(2ꢀ-hydroxynaphth-1ꢀ-
yl)-3,4-dimethyl-5-phenylphospholyl}iron(II) 8
1H, 8-Np), 7.79 (d, JHH = 8.8 Hz, 1H, 4-Np), 7.76 (ddd, JHH
7.7 Hz, JHH = 7.7 Hz, JHH = 1.3 Hz, 1H, 7-Np), 7.70 (d, JHH
=
=
A THF (5 mL) solution containing 4 and dipotassium{2-
(2ꢀ-oxynaphth-1ꢀ-yl)-3,4-dimethyl-5-phenylphospholide (d31P
(THF): 76 ppm) (0.5 mmol) was added to a THF (5 mL)
solution of freshly prepared [FeCp*(acac)] (0.5 mmol). The
solvents were evaporated in vacuo and the residue was extracted
into toluene and passed through a pad of silica. The orange
filtrate was evaporated to dryness under reduced pressure
and recrystallised from dichloromethane/methanol. The title
7.5 Hz, 1H, 5-Np), 7.59 (d, JHH = 7.5 Hz, 1H, o-Ph), 7.38 (ddd,
JHH = 7.7 Hz, JHH = 7.7 Hz, JHH = 1.1 Hz, 1H, 6-Np), 7.30
(pseudo-t, JHH = 7.6 Hz, 2H, m-Ph), 7.17 (d, JHH = 8.5 Hz, 1H,
3-Np), 7.15 (pseudo-t, JHH = 7.6 Hz, 1H, p-Ph), 3.93 (s, 3H,
MeO), 2.26 (s, 3H, MeCCP), 1.97 (s, 3H, MeCCP), 1.82 (s, 15H,
Me-Cp*), 1.55 (m, 6H, CH2), 0.19 (m, 9H, CH3). 11: 31P NMR
(CDCl3): d 26.0 (JP–Pt = 4665 Hz, JP–P = 22.4 Hz), 13.1 (JP–Pt
=
3199 Hz, JP–P = 22.4 Hz).
D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1
2 1 7 9

View Article Online
Crystallography
12 M. Smrcina, M. Lorenc, V. Hanus and P. Kocovsky, Synlett., 1991,
231.
All structures measured using graphite monochromated X-
13 R. A. Singer and S. L. Buchwald, Tetrahedron Lett., 1999, 40,
˚
ray Mo-Ka radiation, k = 0.71069 A, on a Kappa CCD
1095.
14 Y. N. Belokon, N. B. Bespalova, T. D. Churkina, I. Cisarova, M. G.
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17 P. Kocovsky, S. Vyskocil and M. Smrcina, Chem. Rev., 2003, 103,
3213.
diffractometer and refined using direct methods in Shelxl. R
given for I > 2r(I).
Crystal data for 5. C33H35OPRu, M = 579.65, triclinic, space
¯
˚
group P1, a = 9.992(5), b = 11.740(5), c = 12.042(5) A, a =
◦
3
˚
79.530(5), b = 71.170(5), c = 89.490(5) , U = 1312.9(10) A .
Z = 2, Dc = 1.466 g cm−3, F(000) = 600. l = 0. 0.683 cm−1,
T = 150.0(10) K. Of 7645 independent reflections out of a total
of 11067 from a pale yellow cube of dimensions 0.20 × 0.20 ×
0.20 mm over h = −13 to 14, k = −16 to 16, l = −16 to 16◦
at 150(10)K, 6403 having I > 2r(I) were refined on F2. wR2 =
0.0824, R1 = 0.0366, GoF = 1.057.
18 P. J. Guiry and C. P. Saunders, Advanced Synthesis & Catalysis, 2004,
346, 497.
19 H. L. Pedersen and M. Johannsen, J. Org. Chem., 2002, 67, 7982.
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Chem. Soc., 2000, 122, 9870.
Crystal data for 8. C32H33FeOP, M = 520.40, monoclinic,
space group P21/c, a = 10.492(1), b = 8.013(1), c = 31.164(1)
◦
3
−3
˚
˚
A. b = 93.320(1) , U = 2615(6) A . Z = 4, Dc = 1.322 g cm ,
F(000) = 1096. l = 0.661 cm−1, T = 298(5) K. Of 5924
independent reflections from a total of 10129 collected as above
using an orange needle of dimensions 0.20 × 0.08 × 0.08 mm
over h = −13 to 13, k = −9 to 10, l = −40 to 40◦, 4619 having
I > 2r(I) were refined on F2. wR2 = 0.1180, R1 = 0.0426, GoF =
1.079.
26 K. Tanaka and G. C. Fu, J. Org. Chem., 2001, 66, 8177.
27 S. Qiao and G. C. Fu, J. Org. Chem., 1998, 63, 4168.
28 M. Ogasawara, K. Yoshida and T. Hayashi, Organometallics, 2001,
20, 3913.
Crystal data for 12. C41H52Cl8OP2PtRu, M = 1202.53,
monoclinic, space group P21/n, a = 9.809(5), b = 24.651(5),
29 C. Ganter, C. Kaulen and U. Englert, Organometallics, 1999, 18,
5444.
◦
3
˚
˚
30 X. Sava, L. Ricard, F. Mathey and P. Le Floch, Organometallics,
2000, 19, 4899.
31 M. Melaimi, F. Mathey and P. Le Floch, J. Organomet. Chem., 2001,
640, 197.
32 C. E. Garrett and G. C. Fu, J. Org. Chem., 1997, 62, 4534.
33 L. S. Wang and T. K. Hollis, Org. Lett., 2003, 5, 2543.
34 D. Carmichael, J. Klankermayer, L. Ricard and N. Seeboth, Chem.
Commun., 2004, 1144.
35 G. E. Herberich and B. Ganter, Inorg. Chem. Commun., 2001, 4, 100.
36 C. Burney, D. Carmichael, K. Forissier, J. C. Green, F. Mathey and
L. Ricard, Chem. Eur. J., 2003, 9, 2567.
c = 19.909(5) A, b = 91.420(5) , U = 4813(3) A . Z = 4, Dc =
1.660g cm−3, F(000) = 2376. l = 3.759 cm−1, T = 150.0(10)K. Of
7527 independent reflections out of a total of 12590 collected as
above from a yellow needle of dimensions 0.60 × 0.20 × 0.10 mm
over h = −11 to 11, k = −28 to 26, l = −23 to 23◦ at 298(10) K,
5943 having I > 2r(I) were refined on F2. wR2 = 0.1573, R1 =
0.0584, GoF = 1.019.
CCDC reference numbers 258042–258044.
See http://www.rsc.org/suppdata/dt/b4/b418926d/ for cry-
stallographic data in CIF or other electronic format.
37 K. Forissier, L. Ricard, D. Carmichael and F. Mathey,
Organometallics, 2000, 19, 954.
38 D. Carmichael, F. Mathey, L. Ricard and N. Seeboth, Chem.
Commun., 2002, 2976.
39 M. Ogasawara, T. Nagano, K. Yoshida and T. Hayashi,
Organometallics, 2002, 21, 3062.
40 S. Holand, N. Maigrot, C. Charrier and F. Mathey, Organometallics,
1998, 17, 2996.
41 S. Holand, M. Jeanjean and F. Mathey, Angew. Chem., Int. Ed. Engl.,
1997, 36, 98.
42 F. G. Mann and M. J. Pragnell, J. Chem. Soc., 1965, 4120.
43 M. V. Bhatt and S. U. Kulkarni, Synthesis, 1983, 249.
44 A number of phosphole derivatives having simpler aromatic groups in
the 2-position have been shown not to be atropomeric; for example:
L. Routaboul, J. Chiffre, G. G. A. Balavoine, J. C. Daran and E.
Manoury, J. Organomet. Chem., 2001, 637, 364.
45 R. S. Paley, L. A. Estroff, D. J. McCulley, L. A. Martinez-Cruz, A. J.
Sanchez and F. H. Cano, Organometallics, 1998, 17, 1841.
46 There is precedent for facile racemisation of ligands combining five-
and six-membered rings. See for example: T. D. W. Claridge, J. M.
Long, J. M. Brown, D. Hibbs and M. B. Hursthouse, Tetrahedron,
1997, 53, 4035.
Acknowledgements
Financial support for this work from CNRS, Ecole poly-
technique (Gaspard Monge grant to NS) and the European
Commission (through Marie Curie grant HPMT-CT-2001-
00317 to NS and FP5 network funding through HPRN CT-
2001-00172 to DC and JMB) is gratefully acknowledged.
We also wish to thank a referee for suggesting the NMR
experiment involving dissolution of 5 at low temperature which
was used to confirm the exclusive presence of 5a in the crystalline
sample.
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D a l t o n T r a n s . , 2 0 0 5 , 2 1 7 3 – 2 1 8 1
2 1 8 1