Optically active transition metal complexes. Part 123: New chiral half- sandwich ruthenium complexes, in which the arene ligand is tethered to a PN ligand

Article abstract of DOI:10.1039/a909262e

A concept is presented to fix the otherwise labile metal configuration in chiral half-sandwich ruthenium complexes by three-point-attachment ligands. Ligands of this type are prepared by tethering the backbone of the PN ligand 1 to a cyclopentadienyl (2) or arene system (3, 4). In half- sandwich ruthenium complexes the arene-PN ligands bind in a three-point attachment (5, 6) and in a bidentate PN coordination (7-9).

Full text of DOI:10.1039/a909262e

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Optically active transition metal complexes. Part 123:¤ new chiral
half-sandwich ruthenium complexes, in which the arene ligand is
tethered to a PN ligand
H. Brunner,* C. Valerio and M. Zabel”
Institut fur Anorganische Chemie der Universitat Regensburg, 93040 Regensburg, Germany
Received (in Strasbourg, France) 22nd November 1999, Accepted 7th February 2000
Published on the Web 13th April 2000
A concept is presented to Ðx the otherwise labile metal conÐguration in chiral half-sandwich ruthenium complexes
by three-point-attachment ligands. Ligands of this type are prepared by tethering the backbone of the PN ligand 1
to a cyclopentadienyl (2) or arene system (3, 4). In half-sandwich ruthenium complexes the arene-PN ligands bind in
a three-point attachment (5, 6) and in a bidentate PN coordination (7È9).
A wealth of areneÈruthenium complexes [(arene)Ru(LL@)X] is
known, in which the arene can be a Ðve-membered or a six-
membered ring, LL@ is an unsymmetrical chelate ligand and X
is a unidentate ligand. The complexes are neutral or cationic
depending on the arene and the nature of LL@ and X. These
complexes have a pseudo-tetrahedral structure (three-legged
piano stool geometry) containing a chiral central atom. A
series of these complexes has been resolved with respect to the
stereogenic Ru atom.2h18 Most of these complexes turned out
to be conÐgurationally labile at the metal center. As some of
these complexes have served as enantioselective catalysts in
organic transformations19h25 it seemed desirable to stabilize
the ruthenium conÐguration such that it cannot change.
According to a concept presented in ref. 26 this can be done
by using a ligand with three di†erent bonding sites. If such a
ligand, taken as a pure enantiomer, binds to a ruthenium
atom in a three-point attachment, it Ðxes the metal conÐgu-
ration even if hemi-labile ligand arms dissociate interme-
diately, because a chiral three-armed ligand necessarily must
regenerate the original ruthenium conÐguration. Such a three-
point attachment results on tethering a bidentate PN ligand
via its backbone to a p-bonded Ðve- or six-membered arene.
In these ligands the carbon atom in the branching position
becomes a chiral center. Thus, these compounds are the cen-
trally chiral analogues of the planar chiral approach of Ward
and coworkers,27,28 in which an arene with two di†erent
meta-substituents is used to Ðx the ruthenium conÐguration.
In this paper we describe our attempts to tether bidentate
PN ligands to arene rings in half-sandwich ruthenium com-
plexes. As arene-containing ligand arms we chose g5-C H È,
butyllithium in ether at 0 ¡C and successive addition of 6,6@-
dimethylfulvene or the halide compounds at 0 ¡C to give the
ligands 2È4 (Scheme 1).
The reaction of 1 with 6,6@-dimethylfulvene required the
addition of 1 equiv. of NH Cl to obtain the ligand 2 in its
4
neutral form. A mixture of two isomers (2a : 2b \ 80 : 20) dif-
fering in the positions of the carbonÈcarbon double bonds of
the cyclopentadiene part of the molecule was obtained with
69% yield. The compound was characterized by resonances at
[10.29 and [9.83 ppm in the 31PM1HN NMR spectrum.
Resonances at 6.50, 6.20, 5.80 and 2.55 ppm in the 1H NMR
spectrum conÐrmed the presence of the cyclopentadiene ring.
The ligands 3 and 4 were isolated with 57 and 20% yields,
respectively. In the 31PM1HN NMR spectra there were reso-
nances at [2.74 (s) for 3 and 0.44 (s) ppm for 4.
Synthesis of the ruthenium complexes 5–7
The ligand 2 was added in a CH Cl solution to a suspension
2
2
of Ru(PPh ) Cl in dried ethanol. After 3 h of reÑux an
3 3
2
orange solution had formed. Chromatography of the yellow
5
4
g6-C H (CH ) CH È and g6-C H (CH ) È. In all these PN
6
2
3 3
2
6
5
2 2
ligands N was 2-pyridyl and P was diphenylphosphanyl, both
attached to the chiral carbon atom in the branching position.
Results and discussion
Synthesis of the arene-PN ligands 1–4
The bidentate PN precursor 2-(diphenylphosphanylmethyl)-
pyridine 129 was prepared by deprotonation of 2-
methylpyridine with n-butyllithium in ether at 0 ¡C, followed
by reaction with chlorodiphenylphosphine at [78 ¡C.30,31
For the synthesis of the tridentate arene-PN ligands the same
methodology was applied: deprotonation of
1 with n-
¤ Part 122: ref. 1.
” X-Ray structure analyses.
Scheme 1
DOI: 10.1039/a909262e
New J. Chem., 2000, 24, 275È279
275
This journal is ( The Royal Society of Chemistry and the Centre National de la Recherche ScientiÐque 2000

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residue gave complex 5 in 92% yield as an orange yellow
powder. The 31PM1HN NMR spectrum shows the presence of
the main product 5 and a by-product (with NMR spectra
similar to 5) in a ratio of 85 : 15. Each spin system consists of
two doublets, for the major compound 5 at 62.49 and 42.84
ppm (coupling constant of 36 Hz) and for the minor com-
pound at 74.45 and 42.71 ppm (J \ 34 Hz). The resonances at
about 42 ppm are assigned to the triphenylphosphine ligand32
and the resonances at 74.45 and 62.49 ppm to the phosphine
substituent of ligand 2 in agreement with the 31PM1HN NMR
data for [(p-cymene)Ru(1)Cl]PF , 8 and 9.
6
The 1H NMR spectrum of 5 exhibits an unexpected high
Ðeld shift for one proton of the cyclopentadienyl ring. The Cp
resonances are expected to occur at 4.5È5.5 ppm. For 5 there
are three resonances at 4.53, 4.84 and 5.33 ppm with the inte-
gration 1, 2 and 1. Of these 4 protons, three belong to the
cyclopentadienyl ring, the fourth is the proton of the chiral
carbon atom as shown by comparison of the 1H and 1HM31PN
NMR spectra. The fourth cyclopentadienyl proton resonance
appears at 3.13 ppm in agreement with literature data.32 The
FD mass spectrum of the mixture contains peaks due to 5`,
Fig. 1 View of the cation of compound 6. Displacement ellipsoids
for non-H atoms drawn at the 30% probability level (H atoms
omitted for clarity). Selected bond lengths (A) and angles (¡): RuÈP1
2.289(2), RuÈP2 2.315(2), RuÈN1 2.120(6); P1ÈRuÈP2 106.46(8), P1È
RuÈN1 77.1(1), P2ÈRuÈN1 101.6(1).
[5 [ Cl]` and [5 [ PPh ]`. Attempts to separate the 85 : 15
3
mixture were unsuccessful.
Metathesis of 5 with NH PF in methanol replaced the Cl~
corroborated by the FD mass spectrum. The peak m/z \ 976
could be assigned to the cation of complex 7. The structure of
complex 7 was conÐrmed by X-ray structural analysis of a
pale yellow crystal obtained by di†usion of n-hexane into a
solution of 7 in dichloromethane at room temperature (Fig. 2).
The crystals contain the racemate of complex 7.
4
6
anion by the PF ~ anion to give 6. In the crude product, in
6
addition to complex 6, a similar by-product was present.
However, crystallization from acetoneÈethanolÈether (2 : 1 : 1)
a†orded the main product 6 in a pure form. The 31PM1HN
NMR spectrum of 6 exhibits two doublets at 52.24 and 55.60
ppm (J \ 37 Hz) and a resonance for PF at [142.56 ppm. In
6
the 1H NMR spectrum of 6 the pyridine proton H6 is dis-
Synthesis of the ruthenium complexes 8 and 9
placed to high Ðeld (8.21 compared to 8.45 ppm for 5). For 6
all the cyclopentadienyl proton resonances appear between 6.0
and 4.3 ppm. The X-ray structure analysis of 6 shows that the
deprotonated ligand 2 coordinates in a three-point attachment
through the Cp, the pyridine and the phosphine moiety (Fig.
1). The crystals contain the racemate of complex 6.
We attempted to synthesize complexes analogous to 5 and 6
with the g6-arene-PN ligands 3 and 4. As a precursor we
chose [(p-MeC H CHMe )RuCl ] . The Ðrst step was the
6
4
2
2 2
synthesis of complexes in which the ligands 3 or 4 were PN-
coordinated to ruthenium. In the next step the p-cymene
ligand should be replaced by the arene of ligands 3 and 4. In
the literature there are a few reports of such arene exchange
reactions.34,35
We tried to replace the triphenylphosphine ligand in
complex
6
by the optically active ligand (S)-
PPh N(Me)CHMePh.33 The expected product should be a
2
pair of diastereomers that could be separated. First, the reac-
The reaction of [(p-MeC H CHMe )RuCl ] with ligands
6
4
2
2 2
tion of complex 6 and (S)-PPh N(Me)CHMePh was carried
3 and 4, respectively, was carried out analogously to similar
reactions reported in ref. 36, giving complexes 8 and 9 as pairs
of diastereomers. For both complexes the less soluble dia-
stereoisomers (the major diastereomers in the mixtures
obtained) could be separated by repeated fractional crys-
2
out in dichloromethane. After 2 days at room temperature
complex 6 was isolated unchanged. Then, the reaction was
conducted in reÑuxing ethanol for 12 h. After chromatography
on silica gel with diethyl etherÈdichloromethane (50 : 50) a
41 : 59 mixture of compounds was obtained. The NMR data
showed that none of them was the expected product. In the
31PM1HN NMR spectrum there were two di†erent sets of three
doublets of doublets, indicating the presence of three coordi-
nated phosphine ligands in each of the new complexes. The
31P NMR chemical shifts were 45.32, 63.03 and 133.74 ppm
for the minor complex 7, and 141.76, 140.33 and 63.04 ppm
for the major compound, probably a complex with the depro-
tonated ligand 2 coordinating by g5-C H and PPh and two
5
4
2
additional PPH OEt ligands. Thus, in the formation of
2
complex 7 by reaction of 6 with (S)-PPh N(Me)CHMePh in
2
ethanol the pyridine arm of ligand 2 was de-coordinated and a
diphenyl(ethoxy)phosphine ligand was bound, resulting from
the solvolytic cleavage of the PÈN bond in (S)-
PPh N(Me)CHMePh while reÑuxing in ethanol. This was
2
Fig. 2 View of the cation of compound 7. Displacement ellipsoids
for non-H atoms are drawn at the 30% probability level (H atoms
omitted for clarity). Selected bond lengths (A) and angles (¡): RuÈP1
2.363(2), RuÈP2 2.352(2), RuÈP3 2.324(2); P1ÈRuÈP2 101.78(8), P1È
RuÈP3 105.02(8), P2ÈRuÈP3 92.95(8).
276
New J. Chem., 2000, 24, 275È279

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C6-py), 139.21 (139.29) (d, C , PhP, J \ 15.4 Hz), 138.16
q
CP
(138.03) (d, C , PhP, J \ 12.9 Hz), 134.72 (134.69) (s, C4-py),
q
CP
134.29 (134.47) (d, o-PhP, J \ 22.1 Hz), 133.80 (133.73) (d,
CP
o-PhP, J \ 22.5 Hz), 133.07 (131.51) (s, Cp), 132.81 (131.29)
CP
CP
(d, Cp, J \ 1.2 Hz), 128.34 (128.43) (d, Cp, J \ 0.7 Hz),
CP
128.14 (d, p-PhP, J \ 7.9 Hz), 127.89 (d, m-PhP, J \ 8.1
CP
CP
Hz), 127.40 (127.42) (d, m-PhP, J \ 8.2 Hz), 126.06 (s,
CP
p-PhP), 125.47 (125.31) (d, C3-py, J \ 6.4 Hz), 120.52 (s,
CP
C5-py), 57.97 (55.78) (d, CH, J \ 19.1 Hz), 40.62 (41.13) (s,
CP
CH ), 39.59 (41.02) (d, C , J \ 17.8 Hz), 27.78 (d, CH ,
2
q
CP
CP
3
J
\ 10.1 Hz), 26.25 (d, CH , J \ 11 Hz).
CP
3
tallization of the diastereoisomer mixtures from acetoneÈ
ethanol. Up to now it has not been possible to exchange the
cymene ligand in 8 and 9 for the arene of the PN-coordinated
ligands 3 and 4 (reÑux in dichloromethane, chlorobenzene,
and acetonitrile, irradiation).
1-Diphenylphosphanyl-3-(2,4,6-trimethylphenyl)-1-(2-pyridyl)-
ethane 3 and 1-diphenylphosphanyl-3-phenyl-1-(2-pyridyl)-
propane 4
n-Butyllithium (5.65 mmol, 3.53 mL of a 1.6 M solution in
n-hexane) was added dropwise (1 h) at 0 ¡C to a solution of 1
(1.57 g, 5.65 mmol) in 70 mL of diethyl ether. To the deep red
solution was added dropwise 5.75 mmol of aryl halide in 5 mL
diethyl ether. The solution was stirred for 2 h at 0 ¡C and 1 h
at room temperature. The yellow solution was Ðltered to
remove lithium chloride and evaporated to dryness. The
yellow residue was puriÐed by chromatography in diethyl
Experimental
All the syntheses were carried out under an atmosphere of
dry nitrogen with standard Schlenk techniques. The solvents
were dried and saturated with N before use. Chromato-
2
graphy: silica gel 60 (Merck). NMR spectra: Bruker ARX
400 spectrometer; IR spectra: Beckman IR 4240; mass
spectra: Finnigan Mat 95 (FD and FAB) and Finnigan
ether on a short SiO column. After removal of the solvent the
2
product was washed with pentane. It was obtained as a Ðne
112
S
(EI). 6,6@-Dimethylfulvene,37 Ru(PPh ) Cl 38 and
3 3
2
white powder.
[(p-MeC H CHMe )RuCl ] 39 were prepared according to
published methods.
6
4
2
2 2
3: Aryl halide \ 2,4,6-trimethylbenzylchloride. Yield 1.32 g
(3.22 mmol, 57%). Mp 105È107 ¡C. C
H
NP (409.5). EI-
2-(Diphenylphosphanylmethyl)pyridine 1
28 28
MS: m/z 409 (M, 17.5), 394 (M [ CH , 100). 1H NMR (400
3
MHz, CDCl , TMS): d 8.47 (m, 1H, H6-py), 7.67 (m, 2H, Ph),
3
The compound was synthesized as described.29h31 Distillation
under high vacuum (bp 140 ¡C/10~3 mmHg) gave a pale
yellow solid, which was dissolved in ether and Ðltered to
obtain a colourless solution. After evaporation of the solvent
the residue was washed several times with pentane. The
product was a Ðne white powder.
7.34 (m, 6H, Ph ] H4-py), 7.13 (m, 3H, Ph), 6.93 (m, 1H,
H3-py), 6.70 (m, 1H, H5-py), 6.58 (s, 2H, C H ), 3.72 (ddd, 1H,
6
2
J
J
J
\7.6 Hz, J \ 11.2 Hz, J \ 3.4 Hz, CH), 3.27 (ddd, 1H,
HP
HP
HP
\ 6.0 Hz, J \ 11.2 Hz, J \ 13.8 Hz, CH ), 2.84 (ddd, 1H,
2
\ 6.7 Hz, J \ 13.8 Hz, J \ 3.4 Hz, CH ), 2.13 (s, 3H, p-
2
CH ), 1.62 (s, 6H, o-CH ). 31PM1HN NMR (CDCl , H PO
ext.): d [2.74 (s). 13CM1HN NMR (CDCl ): d 161.47 (d, C2-py,
1: Yield 50È57%. 1H NMR (400 MHz, CDCl , TMS): d
3
3
3
3
4
3
8.38 (m, 1H, H6-py), 7.36È7.31 (m, 5H ] 4H, Ph ] H4-py),
3
J
\ 6.2 Hz), 149.38 (s, C6-py), 138.21 (d, C , PhP, J \ 17.5
7.21È7.17 (m, 6H, Ph), 6.92 (m, 1H, H3-py), 6.87 (m, 1H,
H5-py), 3.66 (s, 2H, CH ). 31PM1HN NMR (CDCl , H PO
CP
q
CP
Hz), 136.93 (d, C , PhP, J \ 14.9 Hz), 136.74 (s, o-Ar),
q
CP
2
3
3
4
135.47 (s, C4- py), 135.01 (s, p-Ar), 134.90 (d, o-PhP, J \ 21.5
ext.): d [9.75 (s).
CP
Hz), 133.45 (d, C , Ar, J \ 12.3 Hz), 133.39 (d, o-PhP, J
\
q
CP
CP
19.1 Hz), 129.23 (s, p-PhP), 128.74 (s, m-Ar), 128.26 (d, m-PhP,
1-Diphenylphosphanyl-2,2-dimethyl-2-cyclopentadienyl-1-
(2-pyridyl)ethane 2
J
\ 7.6 Hz), 128.22 (s, p-PhP), 127.97 (d, m-PhP, J \ 6.8
CP
CP
Hz), 124.59 (d, C3-py, J \ 4.9 Hz), 121.04 (s, C5-py), 47.89 (d,
CP
n-Butyllithium (6.07 mmol, 3.8 mL of a 1.6 M solution in n-
hexane) was added dropwise (1 h) at 0 ¡C to a solution of 1
(1.69 g, 6.07 mmol) in 70 mL of diethyl ether. To the deep red
solution was added dropwise a solution of 2,2-dimethylfulvene
(0.75 mL, 6.22 mmol) in 5 mL of diethyl ether. The solution
was stirred for 2 h at 0 ¡C and 1 h at room temperature. Then
a degassed solution of ammonium chloride (0.325 g, 6.07
mmol) in water was added and the solution was stirred for 30
min. The yellow solution was Ðltered to remove lithium chlo-
ride and evaporated to dryness. The residue obtained was dis-
CH, J \11.6 Hz), 32.94 (d, CH , J \ 24.5 Hz), 20.70 (s,
CP
3
2
CP
p-CH ), 19.56 (s, o-CH ).
3
4: Aryl halide \ 1-chloro-2-phenylethane. Yield 0.43 g (1.13
mmol, 20%). Mp 63È65 ¡C. C
H
NP (381.5). EI-MS: m/z
26 24
381.3 (M, 18), 277 (M [ CHCH C H , 100). 1H NMR (400
2 6
5
MHz, CDCl , TMS): d 8.54 (m, 1H, H6-py), 7.48 (m, 2H, Ph),
3
7.44 (m, 3H, Ph), 7.25 (m, 1H, H4-py), 7.15 (m, 2H, Ph), 7.10È
7.00 (m, 6H, Ph), 6.92 (m, 1H, H3-py), 6.83 (m, 2H, Ph), 6.70
(m, 1H, H5-py), 3.67 (m, 1H, CH), 2.60 (m, 1H, CH ), 2.41 (m,
2
2H, CH ), 2.00 (m, 1H, CH ). 31PM1HN NMR (CDCl , H PO
2
2
3
3
4
solved in diethyl ether and chromatographed on a short SiO
column with diethyl ether. After evaporation of the solvent the
ext.): d 0.44 (s). 13CM1HN NMR (CDCl ): d 160.95 (d, C2-py,
2
3
J
\ 7.2 Hz), 149.24 (s, C6-py), 141.44 (s, C , Ph, 136.91 (d,
CP
q
product was washed with pentane. It was obtained as a Ðne
white powder (mixture of isomers 81 : 19).
C , PhP, J \ 14.5 Hz), 136.38 (d, C , PhP, J \ 16.0 Hz),
q
CP
q
CP
135.99 (s, C4-py), 133.85 (d, o-PhP, J \ 20.6 Hz), 133.12 (d,
CP
o-PhP, J \ 19.0 Hz), 129.11 (s, p-PhP), 128.59 (s, m-Ph),
2: Yield 1.60 g (4.19 mmol, 69%). Mp 90 ¡C. C
H
NP
CP
26 26
128.49 (d, m-PhP, J \ 7.3 Hz), 128.29 (s, p-PhP), 128.23 (s,
(383.5). EI-MS: m/z 383 (M, 18), 277 [M [ C(CH ) C H ,
CP
3 2 5
5
o-Ph), 127.82 (d, m-PhP, J \ 6.9 Hz), 125.80 (s, p-Ph), 124.22
100]. 1H NMR (400 MHz, CDCl , TMS; signals of minor
CP
3
(d, C5-py, J \ 5.9 Hz), 121.11 (s, C3-py), 46.42 (d, CH,
isomer in parentheses): d 8.35 (8.34) (m, 1H, H6-py), 7.67 (m,
CP
J
J
\ 13.2 Hz), 33.93 (d, CH , J \ 22.3 Hz), 33.88 (d, CH ,
2H, Ph), 7.25 (m, 6H, Ph ] H4-py), 6.95È6.90 (m, 4H,
Ph ] H3-py), 6.82 (m, 1H, H5-py), 6.53 (6.19) (m, 1H, Cp), 6.17
(6.09) (m, 1H, Cp), 5.80 (6.05) (m, 1H, Cp), 4.25 (m, 1H, CH),
2.55 (2.70) (m, 2H, CH ), 1.43 (1.38) (s, 3H, CH ), 1.23 (1.29) (s,
CP
CP
2
CP
2
\ 13.5 Hz).
{ [g5-C H C(CH ) CH(PPh )C H N]Ru(PPh )}Cl 5
5
4
3 2
2
5
4
3
2
3
3H, CH ). 31PM1HN NMR (CDCl , H PO ext.): d [10.29
To a solution of 1.1 mmol (1.06 g) of Ru(PPh ) Cl in 100 mL
3
3
3
4
3 3 2
([9.83) (s). 13CM1HN NMR (CDCl ): d 160.38 (160.43) (d,
C2-py, J \ 5.2 Hz), 154.03 (156.20) (s, C , Cp), 148.17 (s,
of dried ethanol was added 1.1 mmol (0.42 g) of 2 in 25 mL of
3
dichloromethane. After 3 h reÑux the solution was orange-red.
CP
q
New J. Chem., 2000, 24, 275È279
277

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The residue obtained after evaporation was washed several
times with pentane to remove free triphenylphosphine. Chro-
matography with CH Cl Èacetone (50 : 50) on a SiO column
gave a 85 : 15 mixture of two compounds as a broad orange
band.
C
H
F NOP Ru É CH Cl . FAB-MS (CH Cl ): m/z 976
58 55 6
4
2
2
2 2
(M, 32) (M \ cation of 7), 714 (M [ PPh , 100). 1H NMR
3
(400 MHz, CDCl , TMS): d 8.46 (m, 1H, H6-py), 7.85 (m, 2H,
3
2
2
2
Ph), 7.76 (m, 2H, Ph), 7.60È6.87 (m, 34H, PPh , PPh , H-py),
3
2
5.42 (d, 1H, Cp, J \ 8.0 Hz), 5.02 (d, 1H, Cp, J \ 9.2 Hz), 4.90
(br s, 1H, Cp), 4.62 (br s, 1H, Cp), 4.16 (m, 1H, CH), 3.15 (m,
2H, CH O), 1.02 (s, 3H, CH ), 0.96 (s, 3H, CH ), 0.23 (t, 3H,
5 (and by-product): Yield 92%. Mp 195 ¡C (decomp.). Anal.
found: C, 66.35; H, 5.48; N, 1.72. Calcd.: C, 66.07; H, 5.30; N,
2
3
3
CH , J \ 7.1 Hz). 31PM1HN NMR (CDCl , H PO ext.): d
1.75% for C
H
ClNP Ru Æ H O (799.3). FD-MS (CH Cl ):
3
3
3
4
44 40
2
2
2 2
133.74 (dd, PPh O, JPOvPPh3 \ 27.0 Hz, J
\ 35.1 Hz),
m/z 781 (M, 100), 746 (M [ Cl, 8), 519 (M [ PPh , 64). 1H
2
2
POvP2
3
NMR (400 MHz, CDCl , TMS; signals of by-product in
3
63.03 (dd, PPh 2, JP2vPPh3 \ 51.6 Hz), 45.32 (dd, PPh ),
3
[143.58 (PF ).
parentheses): d 8.45 (8.40) (dd, 1H, H6-py), 7.86 (br t, 2H, Ph),
6
6.65È7.40 (m, 26H, PPh ] PPh ] H-py), 6.01 (5.97) (d, 1H,
[(p-CH C H CH(CH ) )Ru(3)Cl]PF 8 and [(p-CH C H -
3 6 3 2 3 6
CH(CH ) )Ru(4)Cl]PF 9
3 2
[(p-CH C H CH(CH ) )RuCl ] (310 mg, 0.5 mmol) and 1.1
3
3
4
6
4
H-py), 5.33 (5.23) (br s, 1H, Cp), 4.84 (5.10) (m, 1H, Cp), 4.84
(m, 1H, CH), 4.53 (4.75) (br s, 1H, Cp), 3.13 (3.44) (m, 1H, Cp),
1.32 (1.13) (s, 3H, CH ), 1.02 (1.12) (s, 3H, CH ). 31PM1HN
6
3 6
4
3 2
2 2
3
4
3
mmol of ligand 3 or 4 were dissolved in 6 mL of ethanol and 2
mL of dichloromethane was added. After 20 h stirring at room
temperature the red solution was Ðltered and evaporated. The
red-orange residue was dissolved in 10 mL of methanol and
195 mg (1.02 mmol) of NH PF was added. After 1 h an
orange powder had precipitated. The solution was half-
evaporated and Ðltered. The orange precipitate was 8a/b or
9a/b, respectively, enriched in the a isomers. The mother
liquor was evaporated. The residue was dissolved in CH Cl
NMR (CDCl , H PO ext.): d 62.49, 42. 84 (d, J \ 36 Hz)
3
3
[74.45, 42.71 (d, J \ 34 Hz)].
{ [g5-C H C(CH ) CH(PPh )C H N]Ru(PPh )}PF 6
5
4
3 2
2
5
4
3
6
5 (135 mg, 0.173 mmol) was dissolved in dried methanol and
4
6
43 mg (0.26 mmol) of NH PF were added. The mixture was
4
6
stirred for 4 h at room temperature. The solvent was evapo-
rated and the solution in dichloromethane was Ðltered to
remove inorganic salts. After chromatography on a short
silica gel column with acetoneÈmethanol (60 : 40) 6 was
obtained as a yellow powder. The crystallization at [25 ¡C in
a mixture of acetoneÈethanolÈdiethyl ether led to the forma-
tion of small orange needles suitable for X-ray analysis.
2
2
and Ðltered to remove inorganic salts. After concentration and
addition of diethyl ether a yellow powder precipitated con-
taining 8a/b or 9a/b enriched in the b isomers.
8: Yield 77% (diastereomer ratio 71 : 29). Mp 150 ¡C
6: Yield 70%. Mp 220 ¡C (decomp.). Anal. found: C, 55.35;
H, 5.14; N, 1.36. Calcd.: C, 55.38; H, 4.34; N, 1.44% for
(decomp.). Anal. found: C, 55.53; H, 5.26; N, 1.70. Calcd.: C,
55.31; H, 5.13; N, 1.69% for C
(CH Cl ): m/z 680.2 (cation of 8).
H
ClF NP Ru. FAB-MS
38 42
6
2
C
H F NP Ru É CH Cl (975.7). FD-MS (CH Cl ): m/z
44 40 6
3
2
2
2
2
2
2
746 (cation of 6). 1H NMR (400 MHz, acetone-d , TMS): d
8a (major diastereomer): 1H NMR (400 MHz, acetone-d ,
6
6
8.21 (m, 2H, Ph ] H6-py), 8.07 (m, 3H, Ph), 7.57È7.09 (m, 20H,
TMS): d 9.75 (m, 1H, H6-py), 8.12 (m, 2H, o-PhP), 7.80È7.50
Ph ] H4-py), 6.94 (m, 2H, Ph), 6.48 (m, 2H, H3,5-py), 6.09 (s,
1H, Cp), 5.70 (d, 1H, Cp, J \ 10.7 Hz), 5.10 (br s, 1H, CH),
(m, 11H, H3,4,5-py ] PPh ), 6.70 (d, 2H, C H ), 6.50 (d, 1H,
2
6 2
cymene, J \ 7.3 Hz), 6.42 (d, 1H, cymene, J \ 7.3 Hz), 6.14 (d,
1H, cymene, J \ 6.3 Hz), 5.94 (d, 1H, cymene, J \ 6.3 Hz),
5.10 (m, 1H, CH), 4.60 (m, 1H, CH ), 3.47 (m, 1H, CH ), 2.45
4.61 (s, 1H, Cp), 4.33 (s, 1H, Cp), 1.27 (s, 3H, CH ), 1.15 (s, 3H,
3
CH ). 31PM1HN NMR (acetone-d , H PO ext.): d 52.24, 55.60
3
6
3
4
2
2
(d) (J \ 37 Hz), [142.56 (PF ). 13CM1HN NMR (acetone-d ,
(m, 1H, Pri-CH), 2.19 (s, 3H, CH , p-arene), 2.17 (s, 3H,
CH , cymene), 1.88 (s, 3H, CH , o-arene), 1.83 (s, 3H, CH ,
6
6
3
TMS): d 166.57 (d, C2-py, J \ 5.3 Hz), 160.81 (d, C6-py,
J \ 1.9 Hz), 138.77 (s, C4-py), 137.42 (d, C , PPh , J \ 41.7
3
3
3
o-arene), 0.98 (d, 3H, J \ 6.9 Hz, CH , cymene), 0.63 (d, 3H,
q
3
3
Hz), 136.49 (d, C , PPh , J \ 40.0 Hz), 136.20 (d, C , PPh ,
J \ 6.9 Hz, CH , cymene). 31PM1HN NMR (acetone-d ,
q
2
q
2
3
6
J \ 31.4 Hz), 134.52 (d, o-PhP, PPh , J \ 12.1 Hz), 132.36 (d,
H PO ext.): d 60.55 (s), [143.59 (PF ).
3
3
4
6
o-PPh, PPh , J \ 9.9 Hz), 132.26 (d, p-PPh, PPh , J \ 2.4
8b (minor diastereomer): 1H NMR (400 MHz, CDCl ,
2
2
3
Hz), 130.79 (d, p-PhP, PPh , J \ 2.0 Hz), 130.22 (d, p-PPh,
TMS): d 9.43 (m, 1H, H6-py), 8.06 (m, 2H, o-PhP), 7.70È7.32
3
PPh , J \ 2.4 Hz), 129.68 (d, o-PPh, PPh , J \ 10.4 Hz),
(m, 10H, H3,5-py ] PPh ), 7.16 (m, 1H, H4-py), 6.70 (d, 2H,
2
2
2
129.38 (d, m-PPh, PPh , J \ 9.5 Hz), 128.96 (d, m-PhP, PPh ,
C H ), 5.79 (d, 1H, cymene, J \ 6.2 Hz), 5.74 (d, 1H, cymene,
2
3
6
2
J \ 9.6 Hz), 127.99 (d, m-PPh, PPh , J \ 7.8 Hz), 124.91 (s,
J \ 6.2 Hz), 5.66 (d, 1H, cymene, J \ 6.2 Hz), 5.62 (d, 1H,
2
C3-py), 100.90 (s, C5-py), 93.66 (d, C , Cp, J \ 11.9 Hz), 84.85
q
cymene, J \ 6.2 Hz), 4.95 (m, 1H, CH), 3.40 (m, 1H, CH ),
2
3
(d, Cp, J \ 10.6 Hz), 84.58 (s, Cp), 83.13 (d, Cp, J \ 6.7 Hz),
3.16 (m, 1H, CH ), 2.19 (m, 1H, Pri-CH), 2.18 (s, 3H, CH ,
2
82.88 (d, Cp, J \ 6.5 Hz), 72.25 (s, CH), 39.95 (d, C , J \ 7.8
cymene), 1.87 (s, 6H, CH , m-arene), 1.68 (s, 3H, CH , p-
q
3
3
Hz), 28.57 (d, CH , J \ 43.0 Hz), 28.53 (d, CH , J \ 52.3 Hz).
arene), 0.96 (d, 3H, J \ 6.9 Hz, CH , cymene), 0.90 (d, 3H,
3
3
3
J \ 6.9 Hz, CH , cymene). 31PM1HN NMR (CDCl , H PO
Synthesis of {g5-C H C(CH ) CH(PPh )C H N]Ru-
3 2
[PPh (OCH CH )]PPh }PF 7
3
3
3
4
5
4
2
5 4
ext.): d 72.00 (s), [143.58 (PF ).
6
2
2
3
3
6
9: Yield 81% (diastereomer ratio 78 : 22). Mp 140 ¡C
6
(90 mg, 0.1 mmol) and 96 mg (0.3 mmol) of (S)-
(decomp.) Anal. found: C, 51.46; H, 4.71; N, 1.51. Calcd.: C,
50.39; H, 4.58; N, 1.59% for C
FAB-MS (CH Cl ): m/z 652.2 (cation of 9).
PPh N(Me)CHMePh in 50 mL of dried ethanol were reÑuxed
H
ClF NP Ru É CH Cl .
2
36 38
6
2
2 2
for 12 h under nitrogen. The pale yellow solution was evapo-
2
2
rated and the yellow residue was washed several times with
pentaneÈdiethyl ether to remove free phosphine ligands. After
puriÐcation by chromatography on silica gel with
CH Cl Èdiethyl ether (50 : 50) the NMR spectrum of the
9a (major diastereomer): 1H NMR (400 MHz, acetone-d ,
6
TMS): d 9.69 (m, 1H, H6-py), 8.20È6.90 (m, 18H, H3,4,5-py
] PPh ] Ph), 6.10 (d, 1H, cymene, J \ 6.2 Hz), 6.07 (d, 1H,
2
cymene, J \ 6.2 Hz), 5.80 (d, 1H, cymene, J \ 6.2 Hz), 5.34 (d,
2
2
mixture showed that two compounds were present: 7 (41%)
and another ruthenium complex with deprotonated 2 and two
diphenyl(ethoxy)phosphane ligands. By slow di†usion of n-
hexane into a solution of the mixture in dichloromethane it
was possible to crystallize 7 as pale yellow crystals suitable for
X-ray structure analysis.
1H, cymene, J \ 6.2 Hz), 4.61 (m, 1H, CH), 2.86 (s, 1H, CH ),
2
2.82 (s, 1H, CH ), 2.61 (m, 1H, CH ), 2.58 (m, 1H, Pri-CH),
2
2
2.20 (s, 1H, CH ), 1.93 (s, 3H, CH , cymene), 0.99 (d, 3H,
2
3
J \ 6.9 Hz, CH , cymene), 0.77 (d, 3H, J \ 6.9 Hz, CH ,
3
3
cymene). 31PM1HN NMR (acetone-d , H PO ext.): d 59.23 (s),
6
3
4
[142.55 (PF ). 13CM1HN NMR (acetone-d , TMS): d 167.35
6
CP
6
7: Mp 160 ¡C (decomp.). Anal. found: C, 59.35; H, 5.53; N,
0.99. Calcd.: C, 58.76; H, 4.76; N, 1.16% for
(d, C2-py, J \ 7.8 Hz), 159.83 (s, C6-py), 141.47 (s, C , Ph),
q
141.12 (s, C4-py), 136.93 (d, o-PhP, J \ 10.4 Hz), 136.58 (s,
CP
278
New J. Chem., 2000, 24, 275È279

View Article Online
5
6
7
8
9
H. Brunner, B. Nuber and M. Prommesberger, T etrahedron:
Asymmetry, 1998, 9, 3223.
C , PhP), 136.08 (s, C , PhP), 133.35 (d, p-PhP, J \ 2.7 Hz),
CP
q
q
CP
132.41 (d, p-PhP, J \ 2.6 Hz), 132.14 (d, o-PhP, J \ 8.7
CP
H. Brunner, B. Nuber and T. Neuhierl, Eur. J. Inorg. Chem.,
1998, 1877.
Hz), 130.28 (d, m-PhP, J \ 10.1 Hz), 129.45 (d, m-PhP,
CP
J
\ 11.1 Hz), 129.25 (s, m-Ph), 129.19 (s, o-Ph), 126.99 (s,
D. Enders, H. Gielen, G. Raabe, J. Runsink and H. J. Teles,
Chem. Ber./Recl., 1997, 130, 1253.
H. Brunner, R. Oeschey and B. Nuber, J. Chem. Soc., Dalton
T rans., 1996, 1499.
H. Brunner, R. Oeschey and B. Nuber, Organometallics, 1996, 15,
3616.
CP
p-Ph), 126.18 (s, C3-py), 125.88 (d, C5-py, J \ 11.2 Hz),
CP
110.92 (s, C , cymene), 102.16 (s, C , cymene), 96.97 (d, J \ 6.0
q
q
Hz, cymene), 92.01 (d, J \ 8.1 Hz, cymene), 91.97 (d, J \ 8.7
Hz, cymene), 89.18 (d, J \ 2.4 Hz, cymene), 51.71 (d, CH,
J
\ 28.8 Hz), 35.84 (s, CH ), 35.13 (d, CH , J \ 6.7 Hz),
10 I. De los Rios, M. J. Tenorio, M. C. Puerta and P. Valerga, J.
Organomet. Chem., 1996, 525, 57.
CP
2
2
CP
30.86 (s, Pri-CH), 22.52 (s, CH , cymene), 21.76 (s, CH ,
3
3
cymene), 17.85 (s, CH , cymene).
11 H. Brunner, R. Oeschey and B. Nuber, J. Organomet. Chem.,
1996, 518, 47.
3
9b (minor diastereomer): 1H NMR (400 MHz, CDCl ,
3
12 S. Attar, V. J. Catalano and J. H. Nelson, Organometallics, 1996,
15, 2932.
TMS): d 9.47 (m, 1H, H6-py), 8.00È6.91 (m, 18H, H3,4,5-py
] PPh ] Ph), 5.88 (d, 1H, cymene, J \ 6.2 Hz), 5.80 (d, 1H,
2
13 S. Attar, J. H. Nelson, J. Fischer, A. de Cian, J.-P. Sutter and M.
Pfe†er, Organometallics, 1995, 14, 4559.
cymene, J \ 6.2 Hz), 5.50 (s, 2H, cymene), 4.42 (m, 1H, CH),
2.84 (m, 1H, CH ), 2.56 (m, 2H, CH ), 2.30 (m, 1H, Pri-CH),
14 H. Brunner, R. Oeschey and B. Nuber, Inorg. Chem., 1995, 34,
3349.
2
2
3
2.10 (m, 1H, CH ), 1.76 (s, 3H, CH , cymene), 0.94 (d, 3H,
2
J \ 6.9 Hz, CH , cymene), 0.78 (d, 3H, J \ 6.9 Hz, CH ,
cymene). 31PM1HN NMR (acetone-d , H PO ext.): d 74.98 (s),
15 (a) H. Brunner, R. Oeschey and B. Nuber, Angew. Chem., 1994,
106, 941; (b) Angew. Chem., Int. Ed. Engl., 1994, 33, 866.
16 S. K. Mandal and A. R. Chakravarty, Inorg. Chem., 1993, 32,
3851.
3
3
6
3
4
[143.54 (PF ).
6
17 S. K. Mandal and A. R. Chakravarty, J. Chem. Soc., Dalton
X-Ray structure analysis of 6 and 7
T rans., 1992, 1627.
18 S. K. Mandal and A. R. Chakravarty, J. Organomet. Chem., 1991,
417, C59.
Data were collected with an imaging plate di†raction system
(Stoe-IPDS, Stoe & CIE GmbH, Darmstadt, Germany), using
Mo-Ka radiation, j \ 0.710 73 A, with a graphite monochro-
mator. No absorption correction was applied. For data
reduction the Stoe-IPDS software (Stoe, 1998) was used.40
The structure was solved with direct methods (SIR-97; Alto-
mare, 1993)41 and reÐned by full-matrix least-squares tech-
niques (SHELX97; Sheldrick, 1997).42 All H atoms were
included at calculated positions and reÐned using a riding
model.
19 S. Hashiguchi, A. Fujii, J. Takehara, T. Ikariya and R. Noyori, J.
Am. Chem. Soc., 1995, 117, 7562.
20 J. Takehara, S. Hashiguchi, A. Fujii, T. Ikariya and R. Noyori,
Chem. Commun., 1996, 233.
21 K.-J. Haack, S. Hashiguchi, A. Fujii, T. Ikariya and R. Noyori,
Angew. Chem., 1997, 109, 297; Angew. Chem., Int. Ed. Engl., 1997,
36, 285.
22 R. Noyori and S. Hashiguchi, Acc. Chem. Res., 1997, 30, 97.
23 D. L. Davies, J. Fawcett, S. A. Garrat and D. R. Russell, Chem.
Commun., 1997, 1351.
24 D. Carmona, C. Cativiela, S. Elipe, F. J. Lahoz, M. P. Lamata,
M. Pilar, L.-R. de Viu, L. A. Oro, C. Vega and F. Viguri, Chem.
Commun., 1997, 2351.
Crystal data of 6.
C H F NP Ru, M \ 890.75,
44 40 6
3
T \ 297(2) K, clear yellow needles, crystal system: mono-
25 H. Brunner and M. Prommesberger, T etrahedron: Asymmetry,
1998, 9, 3231.
clinic, P2 /c, a \ 10.8328(12), b \ 24.560(2), c \ 17.0067(15) A,
1
b \ 101.074(12)¡, U \ 4440.4(7) A
Ž
3, Z \ 4, k \ 0.52 mm~1,
26 H. Brunner, H.-J. Lautenschlager, W. A. Konig and R. Krebber,
Chem. Ber., 1990, 123, 847.
reÑections collected \ 57 915, independent \ 8584, Ðnal R
indices [I [ 2p(I)]: R \ 0.0573, wR \ 0.1154.
27 (a) B. Therrien and T. R. Ward, Angew. Chem., 1999, 111, 418; (b)
Angew. Chem., Int. Ed., 1999, 38, 405.
1
2
28 B. Therrien, A. Konig and T. R. Ward, Organometallics, 1999, 18,
Crystal data of 7.
C
H
F NOP Ru, M \ 1120.98,
58 55 6
4
1565.
T \ 297(2) K, clear yellow needles, crystal system: triclinic,
29 W. Knebel and R. J. Angelici, Inorg. Chim. Acta, 1973, 7, 713.
30 M. Alvarez, N. Lugan and R. Mathieu, J. Chem. Soc., Dalton
T rans., 1994, 2755.
31 H. Yang, M. AlvarezÈGressier, N. Lugan and R. Mathieu,
Organometallics, 1997, 16, 1401.
32 A. M. Z. Slawin, D. J. Williams, J. Crosby, J. A. Ramsden and C.
White, J. Chem. Soc., Dalton T rans., 1988, 2491.
33 H. Brunner, Angew. Chem., 1999, 111, 1249; Angew. Chem., Int.
Ed., 1999, 38, 1194.
34 P. D. Smith and A. H. Wright, J. Organomet. Chem., 1998, 559,
141.
P1, a \ 10.9743(11), b \ 12.4718(14), c \ 21.493(3) A,
a \ 92.052(14)¡,
U \ 2930.0(6)
b \ 94.429(14)¡,
c \ 91.384(13)¡,
AŽ 3, Z \ 2, k \ 0.43 mm~1, reÑections
collected \ 41 926, independent \ 10 664, Ðnal
[I [ 2p(I)]: R \0.0847, wR \ 0.1836.
R indices
1
2
CCDC reference number 440/168. See http://www.rsc.org/
suppdata/nj/a9/a909262e/ for crystallographic Ðles in .cif
format.
35 B. Therrien, T. R. Ward, M. Pilkington, C. Ho†man, F. Gilard-
oni and J. Weber, Organometallics, 1998, 17, 330.
36 H. Yang, N. Lugan and R. Mathieu, An. Quim., Int. Ed., 1997, 93,
28.
37 K. J. Stone and R. D. Little, J. Chem. Org., 1984, 49, 1849.
38 P. S. Hallman, T. A. Stephenson and G. Wilkinson, Inorg. Synth.,
1970, 12, 237.
39 M. A. Bennett, G. B. Robertson and A. K. Smith, J. Organomet.
Chem., 1972, 43, C41.
40 ST OE IPDS-software, version 2.89, STOE & Cie GmbH, Darm-
stadt, Germany, 1998.
Acknowledgements
We thank the Alexander von Humboldt foundation for a
research grant for C.V. and the Fonds der Chemischen
Industrie for their support of this work.
References
1
Part 122: H. Brunner, M. Niemetz and M. Zabel, Z. Natur-
forsch., 1999, in press.
2
3
4
N. Gul and J. H. Nelson, Polyhedron, 1999, 18, 1835.
N. Gul and J. H. Nelson, Organometallics, 1999, 18, 709.
H. D. Hansen, K. Maitra and J. H. Nelson, Inorg. Chem., 1999,
38, 2150.
41 A. Altomare, G. Cascarano, C. Giacovazzo and A. Guagliardi, J.
Appl. Crystallogr., 1993, 26, 343.
42 G. M. Sheldrick, SHEL XL 97, Program for Crystal Structure
ReÐnement, University of Gottingen, Gottingen, Germany, 1997.
New J. Chem., 2000, 24, 275È279
279