Regioselective addition of PRPh2 to the Cα atom of the diphenylallenylidene ligand of [Ru(η5-C5H5)(C=C=CPh 2)(CO)(PPri3)]BF4

Article abstract of DOI:10.1021/om980577d

The allenylidene ligand of[Ru(η⁵-C₅H₅){C= C=CPh₂}(CO)(PPrⁱ₃)]BF₄ adds PHPh₂, PMePh₂, and PPh₃ selectively at the C_α atom, whereas OH

Full text of DOI:10.1021/om980577d

5434
Organometallics 1998, 17, 5434-5436
Regioselective Ad d ition of P RP h 2 to th e Cr Atom of th e
Dip h en yla llen ylid en e Liga n d of
[Ru (η5-C5H5)(CdCdCP h 2)(CO)(P P r i )]BF 4
3
Miguel A. Esteruelas,* Angel V. Go´mez, Ana M. Lo´pez, J avier Modrego, and
Enrique On˜ate
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
Received J uly 8, 1998
Summary: The allenylidene ligand of [Ru(η5-C5H5){Cd
Sch em e 1
CdCPh2}(CO)(PPri )]BF4 adds PHPh2, PMePh2, and
3
PPh3 selectively at the CR atom, whereas OH- and
[OMe]- are added at the Cγ atom.
EHT-MO calculations on transition-metal allenylidene
complexes indicate that the CR and Cγ atoms of the
allenylidene ligands are electrophilic centers and that
the Câ atom is nucleophilic.1 There are marked differ-
ences in reactivity depending upon the particular me-
tallic fragment which stabilizes the allenylidene unit.
This is nicely illustrated by the behavior of diphenyl-
allenylidene in iron triad complexes. For example, Os-
(η5-C5H5)Cl(CdCdCPh2)(PPri ) is nucleophilic and re-
3
acts with HBF4 and dimethyl acetylendicarboxylato to
afford [Os(η5-C5H5)Cl(CCHdCPh2)(PPri3)]BF4 and Os(η5-
C5H5)Cl{CdC(CO2Me)C(CO2Me)dCdCPh2}(PPri ).2 In
3
contrast, the cationic compounds [Os{C[C(O)OMed
CH2}(CdCdCPh2)(CO)(PPri ) ]BF4,3 [Ru(η5-C9H7)(Cd
3 2
CdCPh2)L2]PF6 (L2 ) 2 PPh3, dppe, dppm),1c,4 [RuCl(Cd
CdCPh2)(dppm)2]PF6,5 [Ru(η5-CnHm)(CdCdCPh2)(PPh3)-
{κ1-Ph2PCH2C(O)But}]PF6 (CnHm ) C5H5, C9H7),6 and
[Ru(η5-C9H4Me3)(CO)(PPh3)]+,9 and [RuCl(η6-C6H4X2)-
(PMe3)]+ (X ) H, Me),10 show stronger electrophilic
character and add alcohols at the CR-Câ double bond
of the allenylidene to afford R,â-unsaturated alkoxycar-
bene derivatives.
The reactivity of these allenylidene complexes toward
phosphines4 seems to be controlled not only by the
metallic fragment but also by the cone angle of the
phosphine. This may be the reason that reactions with
phosphines bulkier than PMe2Ph have not been previ-
ously observed.
7
[RuCl(CdCdCPh2){N(CH2CH2PPh2)3}]PF6 are electro-
philic and react with RLi and Na[OCH3] to give alkynyl
derivatives resulting from regioselective additions at the
Cγ atom of the allenylidene.
Diphenylallenylidene groups stabilized by less basic
metallic fragments, such as [Ru(η5-C5H5)(CO)(PPri )]+,8
3
(1) (a) Berke, H.; Huttner, G.; Von Seyerl, J . Z. Naturforsch. 1981,
36b, 1277. (b) Edwards, A. J .; Esteruelas, M. A.; Lahoz, F. J .; Modrego,
J .; Oro, L. A.; Schrickel, J . Organometallics 1996, 15, 3556. (c)
Cadierno, V.; Gamasa, M. P.; Gimeno, J .; Gonza´lez-Cueva, M.; Lastra,
E.; Borge, J .; Garc´ıa-Granda, S.; Pe´rez-Carren˜o, E. Organometallics
1996, 15, 2137. (d) Esteruelas, M. A.; Go´mez, A. V.; Lo´pez, A. M.;
Modrego, J .; On˜ate, E. Organometallics 1997, 16, 5826.
(2) Crochet, P.; Esteruelas, M. A.; Lo´pez, A. M.; Ruiz, N.; Tolosa, J .
I. Organometallics 1998, 17, 3479.
(3) Bohanna, C.; Callejas, B.; Edwards, A. J .; Esteruelas, M. A.;
Lahoz; F. J .; Oro, L. A.; Ruiz, N.; Valero, C. Organometallics 1998,
17, 373.
(4) Cadierno, V.; Gamasa, M. P.; Gimeno, J .; Lo´pez-Gonza´lez, M.
C.; Borge, J .; Garc´ıa-Granda, S. Organometallics 1997, 16, 4453.
(5) (a) Pirio, N.; Touchard, D.; Toupet, L.; Dixneuf, P. H. J . Chem.
Soc., Chem. Commun. 1991, 980. (b) Touchard, D.; Pirio, N.; Dixneuf,
P. H. Organometallics 1995, 14, 4920.
We report herein that PHPh2 adds regioselectively to
the CR atom of the allenylidene ligand in [Ru(η5-C5H5)-
(CdCdCPh2)(CO)(PPri )]BF4 (1) to afford adduct 2
3
according to Scheme 1. Characteristic spectroscopic
features of 2 are the CdCdC stretching frequency in
the IR spectrum at 1884 cm-1 and the three resonances
in the 13C{1H} NMR spectrum at 215.7, 104.5, and 71.8
ppm for the Câ, Cγ, and CR allenyl carbon atoms.
Complex 2 reacts with Et3N in toluene to afford the
neutral allenyl-phosphine derivative Ru(η5-C5H5)-
{C(PPh2)dCdCPh2}(CO)(PPri ) (3), which regenerates
3
(6) Crochet, P.; Demerseman, B.; Vallejo, M. I.; Gamasa, M. P.;
Gimeno, J .; Borge, J .; Garc´ıa-Granda, S. Organometallics 1997, 16,
5406.
(7) Wolinska, A.; Touchard, D.; Dixneuf, P. H.; Romero, A. J .
Organomet. Chem. 1991, 420, 217.
2 by protonation with HBF4‚OEt2. A view of the
molecular geometry of 3 is shown in Figure 1.
(8) (a) Esteruelas, M. A.; Go´mez A. V.; Lahoz, F. J .; Lo´pez, A. M.;
On˜ate, E.; Oro, L. A. Organometallics 1996, 15, 3423. (b) Esteruelas,
M. A.; Go´mez A. V.; Lo´pez, A. M.; On˜ate, E.; Ruiz, N. Organometallics
1998, 17, 2297.
(9) Gamasa, M. P.; Gimeno, J .; Gonza´lez-Bernardo, C.; Borge, J .;
Garc´ıa-Granda, S. Organometallics 1997, 16, 2483.
(10) Pilette, D.; Ouzzine, K.; Le Bozec, H.; Dixneuf, P. H.; Rickard,
C. E. F.; Roper, W. R. Organometallics 1992, 11, 809.
10.1021/om980577d CCC: $15.00 © 1998 American Chemical Society
Publication on Web 10/31/1998

Notes
Organometallics, Vol. 17, No. 24, 1998 5435
F igu r e 2. Partially optimized structures of Ru(η5-C5H5)-
{C(OMe)dCdCH2}(CO)(PH3) (a ) and Ru(η5-C5H5)(CtCC-
(OMe)H2}(CO)(PH3) (b) obtained by ab initio calculations
at the MP2 level using the LANL2DZ basis for Ru and P,
and 6-31G for the rest of atoms.
F igu r e 1. Molecular diagram of complex 3. Selected bond
lengths (Å) and angles (deg): Ru(1)-P(1) 2.325(2), Ru(1)-
C(1) 2.139(5), C(1)-C(2) 1.292(7), C(2)-C(3) 1.333(7), C(3)-
C(4) 1.478(7), C(3)-C(10) 1.518(7), P(2)-C(1) 1.827(5),
P(2)-C(16) 1.841(5), P(2)-C(22) 1.840(5); Ru(1)-C(1)-C(2)
122.6(4), Ru(1)-C(1)-P(2) 117.0(2), C(1)-C(2)-C(3) 178.7(5),
C(2)-C(3)-C(4) 123.4(4), C(2)-C(3)-C(10) 119.1(4), C(1)-
P(2)-C(16) 106.6(2), C(1)-P(2)-C(22) 103.4(2).
Sch em e 2
The geometry around the ruthenium center in 3 is
close to octahedral, with the cyclopentadienyl ligand
occupying three sites of a face. The Ru-C(1) distance
[2.139(5) Å] is that expected for a Ru-Csp2 single bond
and comparable to the related distance in alkenyl-
ruthenium complexes.11 The C(1)-C(2) [1.292(7) Å] and
C(2)-C(3) [1.333(7) Å] bond lengths, as well as the
C(1)-C(2)-C(3) angle [178.7(5)°], which are in agree-
ment with those reported for other transition-metal
compounds of this type,12 strongly support the allenyl
formulation.13 In accordance with the structure shown
in Figure 1, the IR spectrum of 3 shows the character-
istic CdCdC stretching frequency at 1867 cm-1, and
the 13C{1H} NMR spectrum contains the three reso-
nances corresponding to the Câ, Cγ, and CR atoms at
200.0, 99.1, and 84.3 ppm.
The exclusive formation of 4 starting from 3 and 1
suggests that the addition of bulky phosphines to the
CR atom is kinetic and thermodynamically favored over
addition at the Cγ atom. The origin of this preference
may be the steric congestion due to the phenyl groups
on the Cγ atom.4 In fact, theoretical calculations at the
MP2 level on the model compounds [Ru(η5-C5H5)-
{C(PH3)dCdCH2}(CO)(PH3)]+ and [Ru(η5-C5H5){CtCC-
(PH3)H2}(CO)(PH3)]+ indicate that both isomers are
minima on the potential energy surface and that the
difference of energy between them is not more than 3
Complex 3 reacts with MeI to give the I- salt of the
allenyl-phosphonio cation [Ru(η5-C5H5){C(PMePh2)d
CdCPh2}(CO)(PPri )]+ (4). The [BF4]- salt is obtained
3
kcal‚mol-1
.
by direct reaction of 1 with PMePh2 in CH2Cl2 as
solvent. Similarly, treatment of 1 with PPh3 affords
[Ru(η5-C5H5){C(PPh3)dCdCPh2}(CO)(PPri3)]BF4 (5). The
identity of 4 and 5 are confirmed by a comparison of
spectroscopic data with that for 2 and 3 (see Experi-
mental Section).
In contrast to PRPh2 (R ) H, Me, Ph), the nucleo-
philes [OMe]- and OH- add at the Cγ atom of 1, leading
to the alkynyl complexes Ru(η5-C5H5)(CtCC(OR)Ph2}-
(CO)(PPri ) [6 (R ) Me), 7 (R ) H)] in Scheme 2. Their
3
formation is mainly supported by the IR and 13C{1H}
NMR spectra. The IR spectra show the ν(CtC) bands
at 2108 (6) and 2119 (7) cm-1, while the 13C{1H} NMR
spectra contain resonances at 107.6 and 96.5 (6) and
112.1 and 95.3 (7) ppm, corresponding to the Câ and CR
atoms of the alkynyl ligands.
(11) (a) Torres, M. R.; Vegas, A.; Santos, A.; Ros, J . J . Organomet.
Chem. 1987, 326, 413. (b) Torres, M. R.; Santos, A.; Perales, A.; Ros,
J . J . Organomet. Chem. 1988, 353, 221. (c) Romero, A.; Santos, A.;
Vegas, A. Organometallics 1988, 7, 1988. (d) Lo´pez, J .; Santos, A.;
Romero, A.; Echavarren, A. M. J . Organomet. Chem. 1993, 443, 221.
(e) Esteruelas, M. A.; Lahoz, F. J .; Lo´pez, A. M.; On˜ate, E.; Oro, L. A.
Organometallics 1994, 13, 1669. (f) Cadierno, V.; Gamasa, M. P.;
Gimeno, J .; Borge, J .; Garc´ıa-Granda, S. Organometallics 1997, 16,
3178.
Although the alkoxyallenyl complex Ru(η5-C5H5)-
{C(OMe)dCdCPh2}(CO)(PPri ) has been previously
3
(12) (a) Kolobova, N. E.; Ivanov, L. L.; Zhvanko, O. S.; Khitrova, O.
M.; Batsanov, A. J .; Struchkov, Yu. T. J . Organomet. Chem. 1984, 265,
271. (b) Wouters, J . M. A.; Klein, R. A.; Elsevier, C. J .; Zoutberg, M.
C.; Stam, C. H. Organometallics 1993, 12, 3864. (c) Aumann, R.; J asper,
B.; La¨ge, M.; Krebs, B. Chem. Ber. 1994, 127, 2475. (d) Wouters, J . M.
A.; Klein, R. A.; Elsevier, C. J .; Ha¨ming, L. M. C.; Stam, C. H.
Organometallics 1994, 13, 4586. (e) Fischer, H.; Reindl, D.; Troll, C.;
Leroux, F. J . Organomet. Chem. 1995, 490, 221. (f) Blenkiron, P.;
Corrigan, J . F.; Taylor, N. J .; Carty, A. J .; Doherty, S.; Elsegood, M.
R. J .; Clegg, W. Organometallics 1997, 16, 297.
reported,8a isomerization of 6 into this derivative is not
observed. This is in agreement with theoretical calcula-
tions on the complexes Ru(η5-C5H5){C(OMe)dCdCH2}-
(CO)(PH3) and Ru(η5-C5H5)(CtCC(OMe)H2}(CO)(PH3)
(a and b in Figure 2), which indicate that the second
model compound is 9.29 kcal‚mol-1 more stable than the
first one.14 Furthermore, according to EHT-MO calcula-
tions,1d the net charge on the CR atom of [Ru(η5-C5H5)-
(CdCdCH2)(CO)(PH3)]+ (-0.36) is significantly higher
(13) J acobs, T. L. In The Chemisty of the Allenes; Landor, S. R., Ed.;
Academic Press: London, U. K., 1982; Vol. 2.

5436 Organometallics, Vol. 17, No. 24, 1998
Notes
of toluene was treated with Et3N (38 µL, 0.28 mmol). The
mixture was stirred for 1 h, and the yellow suspension was
filtered. Solvent was removed in vacuo, and the residue was
washed with methanol to afford a yellow solid. Yield: 156 mg
(80%). Anal. Calcd for C42H46OP2Ru: C, 69.12; H, 6.35.
Found: C, 68.89; H, 5.96. IR (cm-1): ν(CO) 1925 (vs), ν(Cd
CdC) 1867 (s). NMR (C6D6): 1H δ 7.95-6.85 (20H, Ph), 4.72
(s, 5H, Cp), 1.98 (m, 3H, PCHCH3), 1.01 (dd, 9H, J (HH) ) 7.2,
J (PH) ) 14.1, PCHCH3), 0.76 (dd, 9H, J (HH) ) 7.1, J (PH) )
than that on Cγ (-0.05). So, the addition of hard
nucleophiles at the Cγ atom of 1 appears to be favored
from an electronic point of view.
In conclusion, the allenylidene ligand of 1 adds bulky
phosphines at the CR atom, whereas hard nucleophiles
such as OMe- and OH- add at the Cγ atom. The
preference of the phosphine nucleophiles has its origin
in the steric congestion due to the phenyl groups on the
Cγ atom. However, the preference of the hard nucleo-
philes seems to be electronic and related to the smaller
net charge on the Cγ atom.
12.9, PCHCH3); 31P{1H} δ 70.0 (d, J (PP) ) 5.3, PPri ), 12.4 (d,
3
J (PP) ) 5.3, PPh2); 13C{1H} δ 207.1 (dd, J (PC) ) 20.4, J (PC)
) 16.6, CO), 200.0 (dd, J (PC) ) 6.8, J (PC) ) 3.0, Câ), 142.3,
140.9 (both s, Cipso,Ph), 141.6 (d, J (PC) ) 25.6, Cipso,Ph), 140.6
(d, J (PC) ) 18.9, Cipso,Ph), 136.0-125.4 (Ph), 99.1 (d, J (PC) )
5.6, Cγ), 85.5 (s, Cp), 84.3 (dd, J (PC) ) 71.1, J (PC) ) 10.9,
CR), 27.1 (d, J (PC) ) 22.4, PCHCH3), 20.11 (d, J (PC) ) 2.3,
PCHCH3), 19.21 (s, PCHCH3).
Exp er im en ta l Section
All reactions were carried out with rigorous exclusion of air
using Schlenk-tube techniques. Solvents were dried by the
usual procedures and distilled under argon prior to use. The
starting material [Ru(η5-C5H5)(CdCdCPh2)(CO)(PPri3)]BF4 (1)
was prepared by the published method.8a
P r ep a r a tion of [Ru (η5-C5H5){CtCC(OR)P h 2}(CO)-
(P P r i3)] [R ) Me (6), H (7)]. A solution of 1 (130 mg, 0.20
mmol) in 5 mL of THF was treated with Na[OMe] (19 mg, 0.35
mmol) or KOH (50 mg, 85%, 0.76 mmol). The resulting
suspension was stirred for 10 min or 4 h, respectively. Solvent
was removed in vacuo, and the residue was extracted in 10
mL of toluene or 30 mL of hexane. The suspension was
filtered, and solvent was removed in vacuo. The residue was
washed with cold methanol to afford 6 or 7 as white solids. 6:
Yield: 89 mg (75.1%). Anal. Calcd for C31H39O2PRu: C, 64.46;
H, 6.83. Found: C, 64.78; H, 6.10. IR (cm-1): ν(CtC) 2108
(m), ν(CO) 1938 (vs). NMR (C6D6): 1H δ 7.96 (m, 4H, o-Ph),
7.21 (m, 4H, m-Ph), 7.07 (m, 2H, p-Ph), 4.79 (s, 5H, Cp), 3.57
(s, 3H, OMe), 1.90 (m, 3H, PCHCH3), 1.02 (dd, 9H, J (HH) )
7.1, J (PH) ) 14.5, PCHCH3), 0.78 (dd, 9H, J (HH) ) 7.1, J (PH)
) 13.1, PCHCH3); 31P{1H} δ 74.8 (s); 13C{1H} δ 206.3 (d, J (PC)
) 18.1, CO), 147.7, 147.4 (both s, Cipso), 128-126.6 (Ph), 107.6
(s, Câ), 96.5 (d, J (PC) ) 21.6, CR), 85.5 (d, J (PC) ) 1.8, Cp),
82.4 (s, Cγ), 51.6 (s, OMe), 27.2 (d, J (PC) ) 23.4, PCHCH3),
20.1 (s, PCHCH3), 19.4 (d, J (PC) ) 1.9, PCHCH3). 7: Yield:
92 mg (79%). Anal. Calcd for C30H37O2PRu: C, 64.15; H, 6.63.
Found: C, 64.32; H, 6.99. IR (cm-1): ν(OH) 3560 (m), ν(Ct
C) 2119 (m), ν(CO) 1941 (vs). NMR (C6D6): 1H δ 7.97 (m, 4H,
o-Ph), 7.20 (m, 4H, m-Ph), 7.07 (m, 2H, p-Ph), 4.79 (s, 5H, Cp),
2.59 (s, 1H, OH), 1.91 (m, 3H, PCHCH3), 1.02 (dd, 9H, J (HH)
) 7.1, J (PH) ) 14.5, PCHCH3), 0.80 (dd, 9H, J (HH) ) 7.1,
J (PH) ) 13.1, PCHCH3); 31P{1H} δ 74.7 (s); 13C{1H} δ 206.2
(d, J (PC) ) 17.4, CO), 149.2 (s, Cipso), 128-126.5 (Ph), 112.1
(s, Câ), 95.3 (d, J (PC) ) 21.1, CR), 85.6 (d, J (PC) ) 1.5, Cp),
75.8 (s, Cγ), 27.2 (d, J (PC) ) 23.3, PCHCH3), 20.2 (s, PCHCH3),
19.4 (d, J (PC) ) 2.3, PCHCH3).
NMR spectra (1H at 300 MHz, 31P at 121.4 MHz, and 13C at
75.4 MHz) were recorded at 293 K, and chemical shifts are
expressed in ppm downfield from Me4Si (1H and 13C) and 85%
H3PO4 (31P). Coupling constants, J , are given in hertz.
P r ep a r a tion of [Ru (η5-C5H5){C(P RP h 2)dCdCP h 2}(CO)-
(P P r i3)]BF 4 [R ) H (2), Me (4), P h (5)]. A solution of 1 (150
mg, 0.24 mmol) in 5 mL of CH2Cl2 was treated with PRPh2
(0.24 mmol). Immediately, the color changed from dark red
to yellow, and solvent was concentrated to ca. 1 mL. By
addition of diethyl ether, a yellow solid precipitated. 2: Yield:
180 mg (93%). Anal. Calcd for C42H47BF4OP2Ru: C, 61.70;
H, 5.79. Found: C, 61.56; H, 6.05. IR (cm-1): ν(PH) 2435 (w),
ν(CO) 1941 (vs), ν(CdCdC) 1884 (m), ν(BF4) 1078 (vs, br).
NMR [(CD3)2CO]: 1H δ 9.20-6.50 (21H, 4 Ph + PH), 5.14 (s,
5H, Cp), 2.20 (m, 3H, PCHCH3), 1.13 (dd, 9H, J (HH) ) 7.0,
J (PH) ) 14.4, PCHCH3), 0.99 (dd, 9H, J (HH) ) 7.0, J (PH) )
12.9, PCHCH3); 31P{1H} δ 73.7 (s, PPri ), 22.4 (s, PHPh2);
3
13C{1H} δ 215.7 (br, Câ), 206 (hidden by signal of solvent, CO),
137.2-121.7 (Ph), 104.5 (d, J (PC) ) 24.1, Cγ), 86.5 (s, Cp), 71.8
(dd, J (PC) ) 17.3, J (PC) ) 11.4, CR), 27.3 (d, J (PC) ) 23.3,
PCHCH3), 19.8 (s, PCHCH3), 18.9 (d, J (PC) ) 1.8, PCHCH3).
4: Yield: 180 mg (90%). Anal. Calcd for C43H49BF4OP2Ru:
C, 62.10; H, 5.94. Found: C, 61.70; H, 5.51. IR (cm-1): ν(CO)
1910 (vs), ν(CdCdC) 1858 (m), ν(BF4) 1066 (vs, br). NMR
(CDCl3): 1H δ 7.68-7.06 (18H, Ph), 6.34 (2H, Ph), 4.95 (s, 5H,
Cp), 2.88 (d, J (PH) ) 12.3, Me), 2.07 (m, 3H, PCHCH3), 1.05
(dd, 9H, J (HH) ) 7.2, J (PH) ) 15.0, PCHCH3), 0.87 (dd, 9H,
J (HH) ) 6.9, J (PH) ) 12.9, PCHCH3); 31P{1H} δ 66.2 (s, PPri3),
24.2 (s, PMePh2); 13C{1H} (plus dept) δ 214.3 (dd, J (PC) ) 1.9,
Câ), 206.6 (dd, J (PC) ) 6.4, J (PC) ) 20.2, CO), 137.4-121.7
(Ph), 101.8 (d, J (PC) ) 23.0, Cγ), 84.8 (s, Cp), 74.6 (dd, J (PC)
) 9.2, J (PC) ) 18.9, CR), 25.7 (d, J (PC) ) 23.0, PCHCH3), 19.6
(s, PCHCH3), 17.8 (d, J (PC) ) 2.8, PCHCH3), 11.6 (d, J (PC) )
X-r a y Str u ctu r e Deter m in a tion of 3. Complex 3 is
triclinic, space group P1h, a ) 10.163(4) Å, b ) 12.749(4) Å, c
) 15.449(6) Å, R ) 98.10(2)°, â ) 100.62(2)°, γ ) 108.76(2)°, Z
) 2; 9507 reflections ((h, +k, (l) were collected at room
temperature with a Siemens Stoe-AED2 diffractometer over
a 2θ range of 3-50°. An empirical absorption correction from
Ψ scans was applied to the data (µ ) 0.55 mm-1). Structural
solutions by Patterson and least-squares refinement (based on
F2) were performed with SHELXTL v. 5.0. The refinement
61.6, Me). 5: Yield: 200 mg (93%). Anal. Calcd for C48H51
-
BF4OP2Ru: C, 64.51; H, 5.75. Found: C, 64.17; H, 5.28. IR
(cm-1): ν(CO) 1929 (vs), ν(CdCdC) 1868 (s), ν(BF4) 1067 (vs,
br). NMR (CDCl3): 1H δ 7.71-6.73 (25H, Ph), 4.74 (s, 5H,
Cp), 2.22 (m, 3H, PCHCH3), 1.11 (dd, 9H, J (HH) ) 7.2, J (PH)
) 14.1, PCHCH3), 0.96 (dd, 9H, J (HH) ) 6.9, J (PH) ) 13.2,
PCHCH3); 31P{1H} δ 62.8 (s, PPri3), 29.8 (s, PPh3); 13C{1H} (plus
dept) δ 217.3 (d, J (PC) ) 2.3, Câ), 206.4 (dd, J (PC) ) 6.0, J (PC)
) 19.3, CO), 135.8-121.5 (Ph), 101.6 (d, J (PC) ) 23.4, Cγ),
85.1 (s, Cp), 74.1 (dd, J (PC) ) 7.8, J (PC) ) 14.7, CR), 27.4 (d,
J (PC) ) 22.5, PCHCH3), 20.0, 18.7 (both s, PCHCH3).
on 5720 (Fo > 0) data converged at wR2(F2) ) 0.1594 for all
2
data and R1(F) ) 0.0528 for 4246 observed data (I > 2σ(I)).
More details in the Supporting Information.
Ack n ow led gm en t. We thank the DGES (Project
PB-95-0806, Programa de Promocio´n General del Cono-
cimiento) for financial support.
P r ep a r a tion of Ru (η5-C5H5){C(P P h 2)dCdCP h 2}(CO)-
(P P r i3) (3). A suspension of 2 (219 mg, 0.27 mmol) in 5 mL
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, anisotropic and isotropic thermal parameters,
experimental details of the X-ray study, and bond distances
and angles (17 pages). Ordering information is given on any
current masthead page.
(14) Although complex 6 appears to be thermodynamically more
stable than Ru(η5-C5H5){C(OMe)dCdCPh2}(CO)(PPri3), isomerization
of the latter into 6 is not observed. This could be due to the fortress of
the CR-OMe bond, which imposes a high activation barrier for the
isomerization.
OM980577D