Synthesis and reactivity of tethered η1:η6-(phosphinoarene)ruthenium bichlorides

Article abstract of DOI:10.1021/om970735l

The coordination properties of ortho- and meta-substituted [(2-diphenylphosphanylethyl)-phenyl]methanol 4a and 4b toward ruthenium(II) have been investigated. To ensure coordination of both the arene and the tethered phosphine, the labile ruthenium arene

Full text of DOI:10.1021/om970735l

330
Organometallics 1998, 17, 330-337
Syn th esis a n d Rea ctivity of Teth er ed
η1:η6-(P h osp h in oa r en e)r u th en iu m Dich lor id es
Bruno Therrien,† Thomas R. Ward,*,† Melanie Pilkington,‡ Christina Hoffmann,‡
Franc¸ois Gilardoni,§ and J acques Weber§
Department of Chemistry and Biochemistry and Laboratory of Chemical and Mineralogical
Crystallography, University of Berne, Freiestrasse 3, CH-3012 Berne, Switzerland,
and Department of Physical Chemistry, University of Geneva, 30 Quai E. Ansermet,
CH-1211 Geneva 4, Switzerland
Received August 18, 1997
The coordination properties of ortho- and meta-substituted [(2-diphenylphosphanylethyl)-
phenyl]methanol 4a and 4b toward ruthenium(II) have been investigated. To ensure
coordination of both the arene and the tethered phosphine, the labile ruthenium arene dimer
[RuCl2(EtO2CC6H5)]2 (7) was synthesized and structurally characterized. Both the ortho
and meta isomers [Ru(4a )Cl2] (9a ) and [Ru(4b)Cl2] (9b) were characterized by X-ray
crystallography. The lack of reactivity of the benzylic alcohol functionality in complexes 9a
and 9b toward various P and C electrophiles is rationalized with extended Hu¨ckel
calculations.
In tr od u ction
however, chiral-at-metal compounds have only found
stoichiometric (and not catalytic) applications in organic
chemistry.
Although the possibility of metal-based chirality was
demonstrated nearly 100 years ago by A. Werner,1 H.
Brunner gave it a new impetus as he initiated a
systematic study of pseudotetrahedral chiral three-
legged piano-stool complexes.2,3 Compounds of the type
[CpML1L2L3] (Cp ) cyclopentadienyl) are chiral at the
metal and can be resolved in many cases if an element
of chirality is introduced either on one of the ligands L,
on the Cp ring, or as a counterion. After diastereomer
separation, the enantiopure resolving agent can be
removed, affording a chiral-at-metal compound.
Recently, organometallic compounds with a d6 elec-
tron count have been used as Lewis-acid catalysts in
C-C bond-forming reactions, e.g., in Diels-Alder and
Mukaiyama reactions.16-23 The prospective of using a
chiral-at-metal piano-stool complex as a catalyst for
such enantioselective transformations is very appealing,
but it is imperative to ensure configurational stability
of the catalyst, as racemization of the latter would have
a dramatic effect on the enantiomeric excess of the
resulting products.
Over the years, a number of groups have studied such
enantiopure complexes together with applications in
organic transformations. Several elegant examples of
the latter come from the groups of Brunner,3-5 Davies,6,7
Faller,8-14 and Gladysz.15 To the best of our knowledge,
We have recently reported a theoretical study on the
configurational stability of coordinatively unsaturated
two-legged piano-stool complexes of the type [(ηn-CnHn)-
ML1L2], η ) 5-7. Although these may have pyramidal
(and thus chiral-at-metal) ground-state geometries,
the computed inversion barriers are low, i.e., <15
† Department of Chemistry and Biochemistry, Universityof Berne.
‡ Laboratory of Chemical and Mineralogical Crystallography, Uni-
versity of Berne.
kcal‚mol-1 24
.
In order to study the role of chirality at the metal in
enantioselective catalysis, we set out to synthesize
complexes incorporating bifunctionalized arenes, acting
§ University of Geneva.
(1) Werner, A. Ber. Dtsch. Chem. Ges. 1911, 44, 1887.
(2) Brunner, H. Angew. Chem., Int. Ed. Engl. 1969, 8, 382; Angew.
Chem. 1969, 81, 395.
(3) Brunner, H. Adv. Organomet. Chem. 1980, 18, 151.
(4) Brunner, H.; Aclasis, J .; Langer, M.; Steger, W. Angew. Chem.,
Int. Ed. Engl. 1974, 13, 810; Angew. Chem. 1974, 81, 864.
(5) Brunner, H.; Fisch, K.; J ones, P. G.; Salbeck, J . Angew. Chem.,
Int. Ed. Engl. 1989, 28, 1521; Angew. Chem. 1989, 101, 1558.
(6) Davies, S. G. Pure Appl. Chem. 1988, 60, 13.
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1990, 383, 161.
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1937.
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(11) Faller, J . W.; Nguyen, J . T.; Ellis, W.; Mazzieri, M. R. Orga-
nometallics 1993, 12, 1434.
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36, 550; Angew. Chem. 1997, 109, 566.
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H. J . Am. Chem. Soc. 1989, 111, 6070.
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Commun. 1992, 1634.
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Int. Ed. Engl. 1994, 33, 1856; Angew. Chem. 1994, 106, 1931.
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39, 5729.
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1992, 6392.
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M. Pure Appl. Chem. 1994, 66, 1463.
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Soc. 1979, 101, 592.
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S0276-7333(97)00735-8 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 01/08/1998

η1:η6-(Phosphinoarene)ruthenium Dichlorides
Organometallics, Vol. 17, No. 3, 1998 331
Sch em e 1
as 10-electron donors, which force pyramidalization at
the metal as illustrated in 1. In the field of early
alcohol 4a . Functionalization of the benzylic alcohol 4a
with BrP(C6F5)2 affords 5a in 32% overall yield.
Ru(II) complexes incorporating the 10-electron-donor
ligand 5a should be well-suited for the activation of
coordinated carbonyl moieties toward nucleophiles.
Despite the presence of an electron-rich diphenylphos-
phine, the neutral η6-arene, coupled with the π-acceptor
properties of perfluorophosphinites,31,32 resulting in
complexes [Ru(η6:η1:η1-5a)L]+ (L ) weakly bound ligand),
are expected to display Lewis-acidic character. At-
transition metal chemistry, tethered cyclopentadienyl
ligands have recently received increasing attention,
mostly in connection with stereospecific olefin polym-
erization.25,26 Comparatively, tethered benzene systems
have received much less attention.27-30 We report
herein the synthesis, characterization, and reactivity of
arene-ruthenium complexes incorporating tethered
phosphines.
tempts to coordinate phosphino phosphinite 5a to
33,34
[RuCl2(p-cymene)]2
yielded complex mixtures of
nearly insoluble materials. FAB MS (peaks with m/ z
>> 2000) and 31P NMR (complex multiplets centered
at 25 ppm (coordinated RPPh2) and 130 ppm (coordi-
nated ROP(C6F5)2) revealed the presence of a poly-
nuclear material, as one could expect for a flexible
bidentate ligand, yielding a 10-membered chelate ring
(without η6-arene coordination). Heating the reaction
mixtureswith or without TlOTfsto obtain the thermo-
dynamic, chelated, mononuclear complex [Ru(η6:η1:η1-
5a )Cl]+ lead to decomposition products: the Arbuzov
rearrangement product of the benzylic phosphinite
(R′CH2OP(C6F5)2), yielding the corresponding phosphine
oxide (R′CH2P(O)(C6F5)2), was identified by 31P NMR
(quintets in the region of -50 ppm).
We, thus, turned our attention to the phosphino
alcohol 4a and its coordination properties. We reasoned
that the alcohol functionality could be judiciously used
to resolve the enantiomers of racemic, planar chiral
complex 9a before introducing the second phosphorus
tether. Reaction of 4a with 0.5 equiv of [Ru(η6-p-
cymene)Cl2]2 yields [Ru(η6-p-cymene)(η1-4a )Cl2] (6a )
quantitatively. All attempts to displace p-cymene from
6a , either thermally or photochemically, resulted in
decomposition, with only traces of 9a . Single crystals
of 6a were submitted for X-ray analysis to determine
its structure. An ORTEP plot of the molecular structure
of compound 6a is presented in Figure 1. Relevant
metrical data are collected in Table 1.
Resu lts a n d Discu ssion
Given the ultimate goal of studying the importance
of electronic asymmetry in enantioselective transforma-
tions, we designed the 10-electron-donor ligand 5a
which incorporates an arene, a strong σ-donor, and a
π-acceptor. This type of electronic asymmetry is re-
sponsible for the high degrees of enantioselection ob-
served with Faller’s {CpMoNOCO} as well as Gladysz’s
{CpReNOPPh3}+ Lewis-acid fragments.14,15
From steric considerations, the diphenylphosphine
(RPPh2) and perfluorodiphenylphosphinite (R′OP(C6F5)2)
donor sites can be considered as nearly equivalent.
From an electronic standpoint, however, these sites
differ markedly. Anchoring these two P-donors on an
arene yields a potential 10-electron-donor ligand which
should ensure pyramidalization of the metal upon η6:
η1:η1-coordination. The synthesis of phosphino phos-
phinite 5a is presented in Scheme 1. Radical addition
of HPPh2 on vinyl aldehyde 2a quantitatively yields 3a ,
which is reduced with NaBH4 to the corresponding
(25) Okuda, J . Comm. Inorg. Chem. 1994, 16, 185.
(26) Shapiro, P. J .; Bunel, E.; Schaefer, W. P.; Bercaw, J . E.
Organometallics 1990, 9, 867.
It has long been known that arene-displacement
reactions at Ru(II) are often low yielding.34 We hoped,
(27) Singewald, E. T.; Mirkin, C. A.; Levy, A. D.; Stern, C. L. Angew.
Chem., Int. Ed. Engl. 1994, 33, 2473; Angew. Chem. 1994, 106, 2524.
(28) Nesmeyanov, A. N.; Krivykh, V. V.; Rubinskaya, M. I. J .
Organomet. Chem. 1979, 164, 159-175.
(31) Ku¨ndig, E. P.; Dupre´, C.; Bourdin, B.; Cunningham, A. J r.;
Pons, D. Helv. Chim. Acta 1994, 77, 421.
(32) King, R. B. Acc. Chem. Res. 1980, 13, 243.
(33) Bennett, M. A.; Huang, T.-N.; Matheson, T. W.; Smith, A. K.
Inorg. Synth. J ohn Wiley: New York, 1982; Vol. 21, p 74.
(34) Bennett, M. A.; Smith, A. K. J . Chem. Soc., Dalton Trans. 1974,
233.
(29) Hartshorn, C. M.; Steel, P. J . Angew. Chem., Int. Ed. Engl.
1996, 35, 2655; Angew. Chem. 1996, 108, 2818.
(30) Le Bozec, H.; Touchard, D.; Dixneuf, P. H. Adv. Organomet.
Chem. 1989, 29, 163.

332 Organometallics, Vol. 17, No. 3, 1998
Therrien et al.
Sch em e 2
Ta ble 1. Selected In ter a tom ic Dista n ces (Å),
In ter a tom ic An gles (d eg) a n d Tor sion An gles (d eg)
for Com p ou n d 6a a
Ru(1)-Cl(1)
Ru(1)-Cl(2)
Ru(1)-P(1)
Ru(1)-C(131)
Ru(1)-C(132)
Ru(1)-C(133)
2.428(2)
2.423(2)
2.357(2)
2.208(6)
2.228(6)
2.244(5)
Ru(1)-C(134)
Ru(1)-C(135)
Ru(1)-C(136)
O(1)-C(109)
C(108)-C(109)
Ru(1)-centroid
2.220(5)
2.200(6)
2.171(6)
1.409(7)
1.520(9)
1.704(7)
Cl(1)-Ru(1)-Cl(2) 87.18(6) centroid-Ru(1)-Cl(1) 127.4(1)
Cl(1)-Ru(1)-P(1) 84.44(5) centroid-Ru(1)-Cl(2) 125.2(1)
Cl(2)-Ru(1)-P(1) 88.00(5) centroid-Ru(1)-P(1) 130.3(1)
P(1)-C(101)-C(102)-C(103)
O(1)-C(109)-C(108)-C(103)
P(2)-C(201)-C(202)-C(203)
O(2)-C(209)-C(208)-C(203)
180.0(4)
-171.8(5)
178.2(4)
-160.7(6)
a
Averaged over the two independent molecules.
F igu r e 2. Molecular structure of [Ru(η6-C6H5CO2Et)Cl2]2
(7). Thermal ellipsoids are at the 50% probability level.
dimer. Since electron-poor arenes give the lowest yields
in displacement reactions with [Ru(η6-p-cymene)Cl2]2,
we reasoned that [Ru(η6-C6H5CO2Et)Cl2]2 (7) may be a
good starting material for the synthesis of 9a , Scheme
2. Birch reduction of ethyl benzoate yielding ethyl-1,4-
cyclohexadiene-3-carboxylate,35-37 followed by reaction
with RuCl3 in EtOH, yields 7 in 96% yield. As dimer 7
is a promising starting material for arene-exchange
reactions, its structure was elucidated by X-ray diffrac-
tion. An ORTEP plot of the molecular structure of
compound 7 is presented in Figure 2. Relevant metrical
data are collected in Table 2.
Treatment of dimer 7 with phosphino alcohol 4a
cleanly affords [Ru(η6-C6H5CO2Et)(η1-4a )Cl2] (8a ). The
intramolecular arene exchange leading to 9a is conve-
niently monitored by 31P NMR spectroscopy. Upon η6:
η1-coordination of 4a , the 31P NMR signal is shifted
downfield by 20 ppm (compared to 8a ). This reaction
is most effectively carried out in a sealed tube in CH2-
Cl2 at 120 °C. On completion, 9a is precipitated by the
addition of hexane to the reaction mixture, yielding an
orange powder. The presence of diastereotopic meth-
F igu r e 1. Molecular structure of [Ru(η6-p-cymene){o-
(C6H4)(CH2OH)CH2CH2PPh2}Cl2] (6a ). Thermal ellipsoids
are at the 50% probability level (only one of the two
independent molecules is depicted).
(35) Rabideau, P. W.; Huser, D. L.; Nyikos, S. J . Tetrahedron Lett.
1980, 21, 1401.
(36) Pertici, P.; Salvadori, P.; Biasci, A.; Vitulli, G.; Bennett, M. A.;
Kane-Maguire, L. A. P. J . Chem. Soc., Dalton Trans. 1988, 315.
(37) Mashima, K.; Kusano, K.-h.; Sato, N.; Matsumura, Y.-i.; Nozaki,
K.; Kumobayashi, H.; Sayo, N.; Hori, Y.; Ishizaki, T.; Akutagawa, S.;
Takaya, H. J . Org. Chem. 1994, 59, 3064.
however, that the chelate effect may force the arene to
displace the coordinated p-cymene in 6a . Having failed,
we sought to synthesize a more labile ruthenium arene

η1:η6-(Phosphinoarene)ruthenium Dichlorides
Organometallics, Vol. 17, No. 3, 1998 333
Ta ble 2. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for Com p ou n d 7
Ru(1)-Ru(1)#1a
Ru(1)-Cl(1)
Ru(1)-Cl(2)
Ru(1)-Cl(1)#1
Ru(1)-C(1)
3.718(1)
2.4440(8)
2.3871(9)
2.4387(8)
2.196(3)
2.158(3)
Ru(1)-C(3)
Ru(1)-C(4)
Ru(1)-C(5)
Ru(1)-C(6)
Ru(1)-centroid
2.169(3)
2.164(3)
2.178(3)
2.160(3)
1.648(3)
Ru(1)-C(2)
Cl(1)-Ru(1)-Cl(2)
86.97(3) Cl(1)-Ru(1)-Cl(1)#1 80.82(3)
129.7(1) Cl(2)-Ru(1)-Cl(1)#1 87.26(3)
126.8(1) Ru(1)-Cl(1)-Ru(1)#1 99.18(3)
centroid-Ru(1)-Cl(1)
centroid-Ru(1)-Cl(2)
centroid-Ru(1)-Cl(1)#1 129.6(1)
a
Symmetry transformations used to generate equivalent at-
oms: #1 -x + 1,-y,-z + 1.
Sch em e 3
F igu r e 3. Molecular structure of [Ru(η6:η1-{o-(C6H4)(CH2-
OH)(CH2CH2PPh2)}Cl2] (9a ). Thermal ellipsoids are at the
50% probability level (solvent omitted for clarity).
ylene protons unambiguously proves the coordination
of the prochiral arene, yielding a racemic, planar chiral
complex 9a . The 1H NMR (300 MHz) higher order
ABCDX spin system arising from the diastereotopic
CH2CH2P protons was simulated, and the resulting
chemical shifts and coupling constants are listed in the
Experimental Section. To our surprise, we were unable
to functionalize the alcohol to a phosphinite or phos-
phite, albeit using many bases (including DBU, NEt3,
DMAP, NaH, n-BuLi, LDA, pyridine) in a wide range
of solvents with various halophosphines namely: ClP-
(Pyrrole)2, ClPPh2, ClP(OCH2CH2O), and BrP(C6F5)2.
Despite the fact that the acidic O-H proton can be
readily exchanged (as deduced from 1H NMR H/D
exchange experiments), it appears that benzylic alkoxide
is totally inert toward P electrophiles. We, thus, studied
the reactivity of 9a toward C electrophiles. In the
presence of a base, various acid chlorides and anhy-
drides (including tosyl, mesyl, acyl) did not react with
9a . Eventually, we reasoned that the alkoxide may be
a “soft nucleophile” and tested allylbromide, which is a
soft electrophile. Again, no reaction was observed. In
all cases, the starting material 9a could be recovered
in high yield after chromatography over silica gel
(Scheme 3). To gain further insight, single crystals of
9a were submitted for X-ray analysis. An ORTEP plot
of the molecular structure of compound 9a is presented
in Figure 3. Relevant metrical data are collected in
Table 3. From this data, we can exclude any direct
intramolecular interaction between the oxygen and the
ruthenium atoms. Even by artificially setting the O(1)-
C(9)-C(2)-C(1) dihedral angle to -90°, thus minimiz-
ing the Ru-O distance, the oxygen remains too distant
from the ruthenium (3.39 Å) to give rise to any signifi-
cant bonding. From these observations, we reasoned
that the alkoxide is sterically inaccessible. To avoid this
problem, we synthesized the meta regioisomer 9b
(Scheme 4). The synthesis of the meta-hydroxyphos-
phine 4b is very similar to the synthesis of its ortho
analog 4a (refer to Scheme 1). Phosphine coordination
yielding 8b, followed by arene displacement, affords 9b
in high yield. The reaction can be monitored by 31P
Ta ble 3. Selected In ter a tom ic Dista n ces (Å),
In ter a tom ic An gles (d eg) a n d Tor sion An gles (d eg)
for Com p ou n d s 9a a n d 9b
9a
9b
Ru(1)-Cl(1)
Ru(1)-Cl(2)
Ru(1)-P(1)
Ru(1)-C(1)
Ru(1)-C(2)
Ru(1)-C(3)
Ru(1)-C(4)
Ru(1)-C(5)
Ru(1)-C(6)
O(1)-C(9)
2.4153(9)
2.3991(8)
2.3261(7)
2.166(3)
2.200(3)
2.224(3)
2.255(3)
2.196(3)
2.199(3)
1.403(5)
1.510(5)
1.693(4)
4.241(3)
2.4378(11)
2.4088(11)
2.3384(10)
2.147(4)
2.198(4)
2.220(4)
2.274(4)
2.234(4)
2.175(4)
1.403(7)
1.511(6)
1.695(4)
3.761(4)
C(2)-C(9)
Ru(1)-centroid
Ru(1)-O(1)
Cl(1)-Ru(1)-Cl(2)
Cl(1)-Ru(1)-P(1)
Cl(2)-Ru(1)-P(1)
O(1)-C(9)-C(2)
centroid-Ru(1)-Cl(1)
centroid-Ru(1)-Cl(2)
centroid-Ru(1)-P(1)
86.56(3)
92.80(3)
88.70(3)
111.2(3)
130.0(1)
126.3(1)
120.6(1)
87.54(4)
93.90(4)
88.61(4)
114.6(4)
128.4(1)
126.4(1)
120.8(1)
C(1)-C(7)-C(8)-P(1)
O(1)-C(9)-C(2)-C(1)
40.4(4)
157.4(3)
-44.4(5)
-34.2(7)a
a
This dihedral angle corresponds to O(1)-C(9)-C(3)-C(2).
Sch em e 4
NMR spectroscopy as the P signal moves from -17.3
(compound 4b) to 22.5 (compound 8b) to 46.3 ppm
(compound 9b). Single crystals were grown, and the
structure was determined by X-ray crystallography. An
ORTEP plot of the molecular structure of compound 9b

334 Organometallics, Vol. 17, No. 3, 1998
Therrien et al.
F igu r e 4. Molecular structure of [Ru(η6:η1-{m-(C6H4)(CH2-
OH)(CH2CH2PPh2)}Cl2] (9b). Thermal ellipsoids are at the
50% probability level (disorder and solvent omitted for
clarity).
is presented in Figure 4. Relevant metrical data are
collected in Table 3.
F igu r e 5. Qualitative interaction diagram for the model
compounds [Ru(η6-C6H6)H3]- and [Ru(η6-C6H5CH2O)(PH3)-
Cl2]-.
The reactivity of the benzylic alcohol 9b toward
nucleophiles was investigated (see Scheme 3). As for
9a , all attempts to functionalize the alcohol were
unsuccessful, yielding unreacted starting material 9b,
Scheme 3. Puzzled by the lack of reactivity of piano-
stool complexes 9, an extended Hu¨ckel (eH) analysis of
the model [Ru(η6-C6H5CH2O)(PH3)Cl2]- was under-
taken.
Exten d ed Hu1 ck el An a lysis. In order to understand
the bonding in the model [Ru(η6-C6H5CH2O)(PH3)Cl2]-,
we constructed a simple three-legged piano-stool [Ru-
(η6-C6H6)H3]-. Then we introduced the benzylic sub-
stituent on the arene, and finally, the hydrides were
replaced by two chlorides capable of π-interaction and
a model PH3.
rise to an interaction, these orbitals remain unperturbed
upon interaction between (C6H5CH2O)- and {RuH3}-.
As a consequence, the “t2g” set of [Ru(η6-C6H5CH2O)-
H3]2- contains no oxygen contribution (<2%). This leads
to a significant negative charge build-up on the oxygen
(-1.50 e-).
Substituting the hydrides of [Ru(η6-C6H5CH2O)H3]2-
by two Cl’s and a PH3 group does not alter the picture
much in [Ru(η6-C6H5CH2O)PH3Cl2]-. The Ru-Cl π
interactions slightly destabilize the corresponding Ru
“t2g” orbitals, which remain essentially Ru-arene non-
bonding. Each Cl ligand contributes ∼10% to each MO
in the “t2g” set. The HOMO is depicted on the right of
Figure 5. The net atomic charges are distributed as
As a starting point, we recall the bonding between
C6H6 and the C3v-symmetric {RuH3}- fragment.38
A
follow: Ru, +0.49 e-; Cl, -0.57 e-; O, -1.50 e-; Cbenzyl
+0.45 e-.
,
simplified interaction diagram is presented in Figure
5. The resulting “three below two” splitting pattern,
reminiscent of octahedral coordination around ruthe-
nium, is evident. With a d6 electron count, the “t2g” set,
essentially located on the metal, is full.
For a frontier-orbital-controlled reaction on [Ru(η6-
C6H5CH2O)PH3Cl2]-, an incoming electrophile should
not interact with the oxygen as it does not contribute
to the highest lying occupied orbitals. If the reaction is
charge-controlled, however, the electrostatic interaction
will favor attack on the oxygen as it bears the greatest
negative charge. Recently, Weber et al. have imple-
mented a formalism to evaluate from eH calculations
the intermolecular interaction energy Eint between an
organometallic substrate S and a model electrophilic or
nucleophilic reagent R.41 In addition to the electrostatic
part,41,42 charge-transfer43 and exchange-repulsion44
components have been included in the calculation of a
Next, we substituted the benzene by a benzyl alkoxide
(C6H5CH2O)-, setting the oxygen in the arene plane.39
The oxygen orbitals hardly contribute (<2%) to the a2u
,
e1g, and e2u arene FMOs, which are mostly responsible
for the Ru-(η6-arene) bonding. The approximate posi-
tion of the oxygen “lone pair orbitals” is hatched in
Figure 5.40 As the Ru-O distance is too large to give
(38) Albright, T. A.; Burdett, J . K.; Whangbo, M.-H. Orbital Interac-
tions in Chemistry; J ohn Wiley: New York, 1985.
(39) Setting the oxygen in the arene plane yields a hyperconjugated
oxygen lone pair, ensuring a maximal contribution of the oxygen
orbitals to the π-system of the coordinated arene. Variation of the
O-CH2-Cipso-CAr dihedral angle to match the structurally determined
angles in 9a or 9b affords even smaller contributions of the lone pairs
to the π-system.
(41) Weber, J .; Stussi, D.; Fluekiger, P.; Morgantini, P.-Y. Comm.
Inorg. Chem. 1992, 14, 27.
(42) Scrocco, E.; Tomasi, J . Top. Curr. Chem. 1973, 42, 95.
(43) Brown, D. A.; Fitzpatrick, N. J .; McGinn, M. A. J . Organomet.
Chem. 1985, 293, 235.
(44) Weber, J .; Flueckiger, P.; Stussi, D.; Morgantini, P.-Y. J . Mol.
Struct. (Theochem) 1992, 221, 175.
(40) By oxygen “lone-pair” we mean orbitals with
a
significant
contribution (>30%) of the oxygen atomic orbitals.

η1:η6-(Phosphinoarene)ruthenium Dichlorides
Organometallics, Vol. 17, No. 3, 1998 335
C(1)-C(7)-C(8)-P(1) for 9a (40.4(4)°) and 9b (44.4(5)°)
indicate that the structure is staggered rather than
eclipsed. For all structurally characterized complexes,
6a , 7, 9a , and 9b, the coordinated η6-arene remains
essentially planar, although incorporation of the phos-
phine tether tends to force the ipso carbon toward the
metal center (maximum out of plane C(5) ) -0.027 Å,
C(6) ) 0.027 Å for 9a ; C(2) ) 0.024 Å, C(3) ) -0.024 Å
for 9b).29 For regioisomers 9a and 9b, the oxygen points
away from (O(1)-C(9)-C(2)-C(1) ) 157.4(3)°) and
toward (O(1)-C(9)-C(3)-C(2) ) -34.3(7)°) the ruthe-
nium, respectively, thus setting the oxygen at 4.241(3)
and 3.761(4) Å from the metal, respectively.
Ou tlook . We have developed a straightforward
synthesis of racemic, planar chiral [Ru(η6:η1-C6H4(CH2-
OH)(CH2CH2PPh2))Cl2] complexes. Despite intensive
efforts, the alcohol could not be functionalized by various
electrophiles. This lack of reactivity can be rationalized
by eH calculations: the absence of oxygen contributions
in the highest lying occupied molecular orbitals does not
favor attack at this position, despite a high negative
charge located on the oxygen. Recently, Ganter et al.
reported the synthesis of a series of substituted phos-
phaferrocenes 10.48 Interestingly, the phosphinite 10b
F igu r e 6. Solvent-accessible surface for [Ru(η6-C6H5-
CH2O)(PH3)Cl2]-, shaded according to the Eint value for
electrophilic attack (red-shaded, most reactive; blue-
shaded, least reactive).
local reactivity index to interpret and predict the regio-
and stereoselectivity of electrophilic and nucleophilic
addition reactions to organometallics. The solvent-
accessible surface of the substrate, generated using the
method suggested by Connolly,45 is used for represent-
ing the intermolecular interaction energies Eint encoded
by color. The most reactive sites are red-shaded, while
the least reactive sites are blue-shaded. The results of
the nucleophilicity index computations for [Ru(η6-C6H5-
CH2O)PH3Cl2]- can be visualized in Figure 6. From this
figure, it is immediately apparent that the most nucleo-
philic region is located between the chlorides. This can
be rationalized by the fact that the chlorides bear a
significant negative charge and contribute to the HOMO,
thus favoring both frontier-orbital- and charge-con-
trolled attack.
X-r a y Da ta . All four structurally characterized
compounds 6a , 7, 9a , and 9b (see Table 4 for a summary
of crystallographic data) were compared with related
X-ray crystal structures retrieved from the Cambridge
Structural Database (CSD). To our knowledge, only one
ruthenium edge-bridged chloro-arene dimer has been
structurally characterized: [Ru(η6-Me6C6)Cl2]2.46 The
data for [Ru(η6-EtO2CC6H5)Cl2]2 (7) is very similar.
Fourteen structures incorporating the [Ru(η6-arene)(P-
donor)Cl2] motif were retrieved from the CSD.47 Again,
all bond lengths and angles for compounds 6a , 9a , and
9b are comparable. Perhaps worth noting is the Ru-
(η6-arene) distance which does not vary significantly
from 6a (1.704(7) Å) to the phosphine-tethered 9a
(1.693(4) Å) and 9b (1.695(4) Å). The dihedral angles
could only be prepared in very low yield from the
corresponding alcohol 10a . We believe that the reason
for this can be traced back to similar orbital arguments
as those presented above. Our attempts to synthesize
complexes of type 1 via a different route will be reported
in due time.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. NMR spectra were recorded on
either a Varian XL 200 (31P), Brucker AM 300 (1H), or Bruker
DRX 400 (19F) spectrometer. Chemical shifts are given in parts
per million (ppm) and coupling constants in hertz. Signals
are referenced against H3PO4 (31P, external reference), CFCl3
(19F, external reference), and tetramethylsilane (1H, internal
reference). Combustion analyses were carried out by Novartis,
Basel. Except for RuCl3‚xH2O (J ohnson Matthey), all chemi-
cals were purchased either from Fluka AG or from Aldrich.
Silica gel was used for flash chromatography (Fluka, silica gel
60). All reactions were carried out under Schlenk conditions,
and all solvents were distilled under nitrogen with standard
desiccating agents. The following compounds were prepared
as described elsewhere: ethyl-1,4-cyclohexadiene-3-carboxy-
late,35 2-vinylbenzaldehyde (2a ),49 3-vinylbenzaldehyde (2b),50
bis(pentafluorophenyl)bromophosphine,31 [RuCl2(p-cymene)]2.34
Str u ctu r e Deter m in a tion . X-ray diffraction data were
collected on a Siemens SMART CCD diffractometer51 at room
temperature using monochromated graphite Mo KR radiation
(48) Ganter, C.; Brassat, L.; Glinsbo¨ckel, C.; Ganter, B. Organome-
tallics 1997, 16, 2862.
(49) Hartman, G. D.; Halczenko, W.; Phillips, B. T. J . Org. Chem.
1985, 50, 2427.
(50) Hirao, A.; Kitamura, K.; Takenaka, K.; Nakahama, S. Macro-
molecules 1993, 26, 4995.
(51) SMART, version 4. Software for the CCD Detector system;
Siemens Analytical Instruments Division: Madison, WI, 1995.
(45) Connolly, M. L. Molecular Surface Program. QCPE Bull. 1 74,
1981.
(46) McCormick, F. B.; Gleason, W. B. Acta Crystallogr., Sect. C
1988, 44, 603.
(47) CSD refcodes for [Ru(η6-arene)(P-donor)Cl2] complexes: BU-
WHEG, BYRUMP, CMRUMP, FALKEY, FUBNOF, GAPZEB, GAPZIF,
KATGOB, KOFYEK, LASGER, LESTOS, LIFSUO, PILHIB, ZESSAR.

336 Organometallics, Vol. 17, No. 3, 1998
Ta ble 4. Su m m a r y of Cr ysta llogr a p h ic Da ta for Com p ou n d s 6a , 7, 9a , a n d 9b
Therrien et al.
6a
7
9a
9b
formula
fw
C
31H35Cl2OPRu
C18H20Cl4O4Ru2
644.28
C22H23Cl4OPRu
577.24
C22H23Cl4OPRu‚CH2Cl2
662.17
626.53
cryst syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
triclinic
P1h
monoclinic
P21/c
11.9235(9)
6.9971(5)
13.814(1)
orthorhombic
P212121
7.3833(4)
12.9998(7)
24.097(1)
triclinic
P1h
12.5570(1)
15.5708(3)
16.2025(3)
67.662(1)
78.023(1)
89.698(1)
2856.94(8)
4
9.4413(8)
11.2840(9)
11.612(1)
84.967(1)
79.061(1)
72.286(1)
1156.4(2)
2
110.023(1)
1082.8(1)
2
1.976
1.910
2312.9(2)
4
1.658
1.221
1160
Z
F
calcd, mg/m3
1.457
0.814
1288
1.658
1.221
576
µ, mm-1
F(000)
632
cryst size, mm
T, K
0.24 × 0.20 × 0.14
0.15 × 0.06 × 0.02
0.20 × 0.20 × 0.20
0.22 × 0.22 × 0.09
298(2)
298(2)
298(2)
298(2)
exposure time, sec
scan range, deg
total no. of data
no. of unique obsd data
no. of variables
goodness-of-fit
R(int)
10
40
10
10
1.39 < θ < 23.24
12002
8067
725
1.160
0.0321
0.0465
0.0977
1.82 < θ < 26.39
5000
2020
131
1.141
0.0275
0.0261
0.0561
1.69 < θ < 26.38
11557
4339
266
1.79 < θ < 23.28
7152
3300
273
1.052
0.0537
0.0349
0.0928
1.060
0.0437
0.0253
0.0617
0.503, -0.407
a
final R1 [I > 2σ(I)]
b
final wR2 (all data)
max, min resid density, e Å-3
0.481, -0.415
0.355, -0.424
0.692, -0.658
R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2(Fo2) ) {∑[w(Fo - Fc2)2]/∑ [w(Fo2)]}; w ) 1/[σ2(Fo2) + P2 + P], where P ) (Fo + 2Fc2)/3.
a
b
2
2
(0.710 73 Å) The relevant structure determination parameters
34.1 mmol), degassed, and cooled to 0 °C. NaBH4 (1.33 g, 35.0
mmol) was added portionwise. The mixture was then allowed
to slowly warm to room temperature and stirred for 4 h. The
solution was then acidified with HCl (5% solution). The
organic layer was separated, and the aqueous layer was
extracted with diethyl ether. The combined organic phases
were washed with water, dried over MgSO4, and concentrated
under vacuum. The product was purified by flash chroma-
tography (hexane/EtOAc gradient 5:1 to 1:1), affording the
phosphino-alcohol 4a in 85% yield (9.28 g, 29.0 mmol). 1H
NMR (CDCl3): 7.7-7.1 (m, 14H, CArH), 4.58 (s, 2H, CH2O),
are given in Table 4. A complete hemisphere of data was
scanned on ω (0.30) with a run time of 10 or 40 s unless
otherwise stated) at the detector resolution of 512 × 512 pixels
and a detector distance of 5.18 cm. A total of 1271 frames
were collected for each data set. Cell constants were obtained
on 60 frames. The collected frames were processed with the
SAINT program52 that automatically performs Lorentz and
polarization corrections. Empirical absorption corrections
were made using the XPREP program from the SHELXTL53
software. The structures were solved by direct methods, and
the refinement was done by full-matrix least-squares of F2
using SHELXL9654 (beta-test version). All non-hydrogen
atoms were refined anisotropically, while hydrogen atoms,
included at calculated positions, were refined in the riding
model with group atomic displacement parameters.
3
2
2.81 (dt, J H-H ) 8.5 Hz, J H-P ) 7.0 Hz, 2H, CH2P), 2.37 (t,
2H, CArCH2), 1.60 (brd, 1H, OH). 31P NMR (CDCl3): -15.8.
Anal. Calcd for C21H20OP‚0.4H2O: C, 77.24; H, 6.42. Found:
C, 77.5; H, 6.2.
Syn th esis of m -C6H4(CH2OH)(CH2CH2P P h 2) (4b). This
compound was prepared similarly to its regioisomer 4a . The
product was purified by flash chromatography (hexane/EtOAc
9:1), affording the phosphino alcohol 4b in 78% yield (5.32 g,
16.6 mmol). 1H NMR (CDCl3): 7.52 (m, 4H, CArH), 7.38 (m,
6H, CArH), 7.26 (dd, 3J H-H ) 7.4 Hz, 3J H-H ) 7.4 Hz, 1H, CArH),
7.24 (s, 1H, CArH), 7.18 (d, 1H, CArH), 7.10 (d, 1H, CArH), 4.67
Syn th esis of o-C6H4(CHO)(CH2CH2P P h 2) (3a ). A de-
gassed, diethyl ether solution (15 mL) containing diphe-
nylphosphine (6.34 g, 34.1 mmol), styrene (2a ) (4.50 g, 34.1
mmol), and AIBN (0.28 g, 1.7 mmol) was irradiated (Hg low-
pressure lamp) in a sealed Schlenk flask for 24 h. The volatile
materials were removed in vacuo. The phosphine 3a proved
to be pure (>95%) by NMR and was used without purification.
1H NMR (CDCl3): 10.10 (s, 1H, CHO), 7.6-7.1 (m, 14H, CArH),
3
2
(s, 2H, CH2O), 2.79 (dt, J H-H ) 8.5 Hz, J H-P ) 8.7 Hz, 2H,
CH2P), 2.48 (t, 2H, CArCH2), 2.3 (brd, 1H, OH). 31P NMR
(CDCl3): -17.3. Anal. Calcd for C21H20OP‚0.2H2O: C, 78.10;
H, 6.37. Found: C, 78.2; H, 6.2.
3
2
2.94 (dt, J H-H ) 8.5 Hz, J H-P ) 7.5 Hz, 2H, CH2P), 2.42 (t,
2H, CArCH2). 31P NMR (CDCl3): -16.1.
Syn th esis of m -C6H4(CHO)(CH2CH2P P h 2) (3b). This
compound was prepared similarly to its ortho-regioisomer 3a ,
starting from 2.80 g (21.2 mmol) of 3-vinylbenzaldehyde
(2b).1H NMR (CDCl3): 10.10 (s, 1H, CHO), 7.6-7.0 (m, 14H,
CArH), 2.80 (m, 2H, CH2P), 2.50 (m, 2H, CArCH2). 31P NMR
(CDCl3): -17.3.
Syn th esis of o-C6H4(CH2OP (C6F 5)2)(CH2CH2P P h 2) (5a ).
To a stirred solution of phosphino-alcohol 4a (1.19 g, 3.71
mmol) in diethyl ether containing triethylamine (5.1 mL, 37
mmol), bis(pentafluorophenyl)bromophosphine (1.66 g, 3.71
mmol) was slowly added by means of a syringe. After 24 h at
room temperature, the suspension was filtered and the vola-
tiles were evaporated in vacuo. Flash chromatography with
hexane:ethyl acetate (1:1) yields phosphino phosphinite 5a in
38% yield (958 mg, 1.4 mmol). 1H NMR (CDCl3): 7.7-7.1 (m,
14H, CArH), 4.87 (d, 3J H-P ) 11.8 Hz, 2H, CH2O), 2.73 (m, 2H,
CH2P), 2.27 (m, 2H, CArCH2). 31P NMR (CDCl3): -16.2 (s,
Syn th esis of o-C6H4(CH2OH)(CH2CH2P P h 2) (4a ).
A
benzene-ethanol mixture (5:1) was charged with 3a (10.84 g,
(52) SAINT, version 4; Siemens Energy and Automation Inc.:
Madison, WI, 1995.
(53) SHELXTL, version 5.03 (for Silicon Graphics). Program Library
for Structure Solution and Molecular Graphics; Siemens Analytical
Instruments Division: Madison, WI, 1995.
(54) Sheldrick, G. M. SHELXL-96; Program for the Refinement of
Crystal Structures; University of Go¨ttingen: Go¨ttingen, Germany,
1996.
3
1P), 87.6 (quin, J F-P ) 34 Hz, 1P). 19F NMR (CDCl3) -6.14
3
3
4
(tm, J F-P ) 34 Hz, J F-F ) 18.3 Hz, J F-F ) 3.8 Hz, 4F),
3
4
-22.34 (tt, J F-F ) 20.4 Hz, 2F), -33.49 (tm, J F-P ) 1.8 Hz,
4F).

η1:η6-(Phosphinoarene)ruthenium Dichlorides
Organometallics, Vol. 17, No. 3, 1998 337
Syn t h esis of [R u (η6-p -cym en e)(η1-o-C6H 4(CH 2OH )-
(CH2CH2P P h 2))Cl2] (6a ). [RuCl2(p-cymene)]2 (0.20 g, 0.33
mmol) and phosphino alcohol 4a (0.210 g, 0.65 mmol) were
dissolved in dichloromethane (10 mL), and the mixture was
stirred for 30 min. Addition of benzene (250 mL) yields a
brownish microcrystalline product 6a (375 mg, 0.60 mmol, 92%
yield). The air-stable solid is placed in a Soxhlet extractor and
extracted under nitrogen with isopropanol alcohol, affording
red crystals suitable for X-ray analysis. 1H NMR (CDCl3): 7.93
g (1.43 mmol) of 9a , 97% yield. Suitable crystals for X-ray
diffraction of 9a were obtained by slow evaporation of a
saturated solution in dichloromethane. 1H NMR (CDCl3): 8.03
(m, 2H, PCArH), 7.55 (m, 2H, CArH), 7.47 (m, 3H, CArH), 7.33
3
(m, 3H, CArH), 6.59 (d, J H-H ) 6.6 Hz, 1H, η6-CArRH), 6.30
3
4
(brd t, J H-H ) 5.5 Hz, J H-H ) 2.4 Hz, 1H, η6-CArâH), 5.59
(dd, J H-H ) 5.5 Hz, 1H, η6-CArδH), 5.00 (dd, 1H, η6-CArγH),
3
2
3
4.67 (dd, J H-H ) 14.0 Hz, J H-H )8.1 Hz, 1H, CHHO), 4.52
3
(dd, J H-H ) 5.1 Hz, 1H, CHHO), 4.22 (dd, 1H, OH), 3.92 (m,
3
3
3
(m, 4H, CArH), 7.53 (m, 6H, CArH), 7.23 (dd, J H-H ) 4.4 Hz,
2J A-B ) 14.0 Hz, J A-C ) 8.8 Hz, J A-D ) 2.9 Hz, J A-X ) 17.3
4J H-H ) 1.5 Hz, 1H, CArH), 7.08 (m, 2H, CArH), 6.87 (dd, 1H,
Hz, 1H, CHAHP), 3.81 (m, J B-C ) 1.8 Hz, J B-D ) 6.3 Hz,
3
3
C
ArH), 5.29 (d, 3J H-H ) 5.9 Hz, 2H, CcymH), 5.10 (d, 2H, CcymH),
3J B-X ) 14.3 Hz, 1H, CHHBP), 2.88 (m, 2J C-D ) 16.0 Hz, 4J C-X
3
3
4
4.46 (d, J H-H ) 5.5 Hz, 2H, CH2O), 2.80 (td, 2H, J H-H ) 9.1
) 34.4 Hz, 1H, CArCHCH), 2.58 (m, J D-X ) 10.5 Hz, 1H, CAr
-
2
3
Hz, J H-P ) 9.2 Hz, CH2P), 2.56 (sep, J H-H ) 7.0 Hz, 1H,
CHHD) (ABCDX spin-system simulated). 31P NMR (CDCl3):
41.5. Anal. Calcd for C21H21Cl2OPRu: C, 51.23; H, 4.30; Cl,
14.40. Found: C, 50.9; H, 4.3; Cl, 14.2.
3
CH(CH3)2), 2.46 (dt, J H-P ) 4.4 Hz, 2H, CArCH2), 2.22 (t, 1H,
OH), 1.91 (s, 3H, CArCH3), 0.88 (d, 6H, CH(CH3)2). 31P NMR
(CDCl3): 20.2. Anal. Calcd for C31H35Cl2OPRu‚0.33C6H6): C,
60.74; H, 5.71. Found: C, 60.8; H, 5.6.
Syn th esis of [Ru (η6:η1-o-C6H4(CH2OH)(CH2CH2P P h 2))-
Cl2] (9b). A 25 mL pressure Schlenk tube was charged with
dichloromethane (10 mL) and 8b (0.405 g, 0.63 mmol). After
3 freeze-pump-thaw cycles, the mixture was heated at 120
°C for 24 h and cooled to room temperature, and the product
was precipitated with hexane (200 mL). The orange solid was
filtered, washed with ether and purified by flash chromatog-
raphy (EtOAc), affording 9b in 65% yield (200 mg, 0.41 mmol).
Suitable crystals for X-ray diffraction of 9b were obtained by
slow evaporation of a saturated solution in dichloromethane.
1H NMR (CDCl3): 7.71 (m, 4H, CArH), 7.40 (m, 6H, CArH), 6.28
Syn th esis of [Ru Cl2(EtO2CC6H5)]2 (7). This complex was
prepared by an analogous method to that used for [RuCl2-
(C6H6)]2.34 A solution of RuCl3‚3H2O (3.85 g, 14.7 mmol) and
4 equiv of ethyl-1,4-cyclohexadiene-3-carboxylate (8.50 g, 55.8
mmol) in ethanol was refluxed for 12 h. The orange, air-stable,
microcrystalline material (4.59 g, 96% yield) was then placed
in a Soxhlet extractor and extracted under nitrogen with
ethanol, affording red crystals suitable for X-ray analysis.
3
1H NMR (CDCl3): 6.48 (d, J H-H ) 5.6 Hz, 4H, CArH), 5.99
3
3
3
(t, J H-H ) 5.6 Hz, 2H, CArH), 5.79 (dd, 4H, CArH), 4.45 (q,
(d, J H-H ) 6.1 Hz, 1H, η6-CArRH), 6.07 (dd, J H-H ) 5.5 Hz,
3J H-H ) 7.0 Hz, 4H, OCH2), 1.40 (t, 6H, CH3). Anal. Calcd
for C9H10Cl2O2Ru: C, 33.56; H, 3.13. Found: C, 33.5; H, 3.1.
Syn t h esis of [R u (η6-C6H 5CO2E t )(η1-o-C6H 4(CH 2OH )-
(CH2CH2P P h 2))Cl2] (8a ). To a dichloromethane solution (20
mL) of dimer 7 (0.406 g, 0.63 mmol), phosphino alcohol 4a (380
mg, 1.19 mmol) was added. The mixture was stirred for 30
min. The solid was precipitated with hexane to give 8a in 98%
yield (0.746 g, 1.17 mmol). 1H NMR (CDCl3): 7.9 (m, 4H,
1H, η6-CArâH), 5.11 (s, 1H, η6-CArH), 5.03 (d, J H-H ) 5.5 Hz,
3
1H, η6-CArδH), 4.72 (dd, J H-H ) 15.1 Hz, J H-H ) 7.4 Hz, 1H,
2
3
3
CHHO), 4.55 (dd, J H-H ) 7.4 Hz, 1H, CHHO), 4.18 (dd, 1H,
OH ), 3.50 (m, 2H, CH 2P), 2.66 (m, 2H, CArCH 2). 31P NMR
(CDCl3): 46.3. Anal. Calcd for C21H21Cl2OPRu‚1.5CH2Cl2: C,
43.6; H, 3.9. Found: C, 43.3; H, 3.8.
Ack n ow led gm en t. T.R.W. thanks Prof. A. Ludi for
his hopsitality, Prof H.-B. Bu¨rgi for stimulating discus-
sions and diffractometer time, the Swiss National
Science Foundation for funding, and the Stiftung fu¨r
Stipendien auf dem Gebiete der Chemie for the award
of a Werner Fellowship (1994-1998).
C
ArH), 7.5 (m, 6H, CArH), 7.3 (m, 1H, CArH), 7.10 (m, 2H, CArH),
3
6.92 (m, 1H, CArH), 6.34 (d, J H-H ) 5.6 Hz, 2H, CesterH), 5.44
3
(t, J H-H ) 5.6 Hz, 1H, CesterH), 5.10 (dd, 2H, CesterH), 4.51 (s,
3
2H, CH2OH), 4.37 (q, J H-H ) 7.0 Hz, 2H, OCH2), 2.88 (m,
2H, CH2P), 2.56 (m, 2H, CArCH2), 1.39 (t, 3H, CH3). 31P NMR
(CDCl3): 21.8. Anal. Calcd for C30H31Cl2O3PRu: C, 56.08; H,
4.86. Found: C, 55.7; H, 4.9.
Syn th esis of [Ru (η6-C6H5CO2Et)(η1-m -C6H4(CH2OH)-
(CH2CH2P P h 2))Cl2] (8b). To a dichloromethane solution (15
mL) of dimer 7 (0.241 g, 0.37 mmol), phosphino alcohol 4b (250
mg, 0.78 mmol) was added. The mixture was stirred for 20
min. The volume was reduced to 5 mL. Then the orange solid
was precipitated with diethyl ether (500 ml) to give 8b in 93%
yield (0.450 g, 0.70 mmol). 1H NMR (acetone-d6): 8.00 (m,
4H, CArH), 7.56 (m, 6H, CArH), 7.15 (m, 2H, CArH), 7.02 (s,
Ap p en d ix
The eH calculations were performed with the CACAO
package, using standard parameters.55-58 All distances
and angles for the model calculations were taken from
the X-ray structure of 9a , except for Ru-H ) 1.7 Å. All
eH parameters were taken from ref 24. The reactivity
index calculations41 were carried out with the modified
eH procedure to include core-core repulsion as formu-
lated by Calzaferri.59
3
3
1H, CArH), 6.90 (d, J H-H ) 6.6 Hz, 1H, CArH), 6.33 (d, J H-H
3
) 6.3 Hz, 2H, CesterH), 5.66 (m, 1H, CesterH), 5.22 (dd, J H-H
)
5.7 Hz, 2H, CesterH), 4.52 (d, 3J H-H ) 5.5 Hz, 2H, CH2OH), 4.35
3
(q, J H-H ) 7.0 Hz, 2H, OCH 2), 4.10 (t, 1H, OH ), 2.88 (m,
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, atomic coordinates, anisotropic thermal parameters,
bond lengths, and bond angles of 6a , 7, 9a , and 9b (16 pages).
Ordering information is given on any current masthead page.
2H, CH2P), 2.47 (m, 2H, CArCH2), 1.32 (t, 3H, CH3). 31P NMR
(acetone-d6): 22.5. Anal. Calcd for C30H31Cl2O3PRu: C, 56.08;
H, 4.86; Cl, 11.04. Found: C, 56.1; H, 4.9; Cl, 11.1.
Syn th esis of [Ru (η6:η1-o-C6H4(CH2OH)(CH2CH2P P h 2))-
Cl2] (9a ). A 25 mL pressure Schlenk tube was charged with
dichloromethane (8 mL), Ru dimer 7 (0.472 g, 0.73 mmol), and
phosphino alcohol 4a (0.469 g, 1.47 mmol). After 3 freeze-
pump-thaw cycles, the mixture was heated at 120 °C for 24
h and cooled to room temperature, and the product was
precipitated with hexane (200 mL). The orange solid was
filtered, washed with ether, and dried in vacuo to give 0.703
OM970735L
(55) Ammeter, J . H.; Bu¨rgi, H.-B.; Thibeault, J . C.; Hoffmann, R.
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(58) Mealli, C.; Proserpio, D. M. J . Chem. Educ. 1990, 67, 399.
(59) Calzaferri, G.; Bra¨ndle, M. ICON & INPUTC. QCPE No. 116.