Ruthenium-mediated cyclometalation reactions of allene and allylphosphine C=C Bonds: Synthesis of j(p),η4-(hexa-2,5-dien-1-yl) diphenylphosphine-ruthenium(ii) complexes

Article abstract of DOI:10.1021/om200668h

The cyclopentadienyl-containing complex [Ru(η⁵-C ₅H₅)(MeCN){k³- (P,C,C)-Ph₂PCH ₂CH=CH2}][PF₆] (1) reacts with allenes, giving regioselectively the η₂-allene complexes [Ru(η⁵- C₅H₅)(MeCN){k(P)-Ph₂PCH₂CHdCH ₂}(η²- CH₂=C=CR¹R ²)][PF₆] [R¹ = R²=Me (3); R ¹ = H, R² = Ph (4); R¹R² =-(CH ₂)₅- (5)]. On the other hand, the reaction of the pentamethylcyclopentadienyl-containing complex [Ru(η⁵-C ₅Me₅)(MeCN){k³(P,C,C)-Ph₂PCH ₂CHdCH₂}][OTf] (2) with allenes yields regio- and stereoselectively the complexes [Ru(η⁵-C₅Me ₅){k(P),η⁴- Ph₂PCH₂CHdCHC(R ¹R²)CHdCH₂}][OTf] [R¹ = R ² = Me (6); R¹ = H. R² = Ph (7); R ¹R² = -(CH₂)₅- (8)] via the intermolecular coupling of allene and allyldiphenylphosphine ligands. The intermediate complex [Ru(η⁵-C₅Me₅)(MeCN) {k(P)- Ph₂PCH₂CHdCH₂}{η²-CH ₂=C=CMe₂}][OTf] (9) has been spectroscopically characterized. The structure of complex [Ru(η⁵-C ₅Me₅){k(P),η⁴-Ph₂PCH ₂CHdCHC- (Me)₂CHdCH₂}][{3,5-(CF ₃)₂C₆H₃}₄B] (6a) has been resolved by X-ray diffraction analysis.

Full text of DOI:10.1021/om200668h

ARTICLE
pubs.acs.org/Organometallics
Ruthenium-Mediated Cyclometalation Reactions of Allene and
Allylphosphine CdC Bonds: Synthesis of j(P),η4-(Hexa-2,5-dien-1-yl)
diphenylphosphineꢀRuthenium(II) Complexes
Amparo Villar, Josefina Díez, Elena Lastra,* and M. Pilar Gamasa*
Departamento de Química Orgꢀanica e Inorgꢀanica, Instituto Universitario de Química Organometꢀalica “Enrique Moles”
(Unidad Asociada al C.S.I.C.), Universidad de Oviedo, 33006 Oviedo, Principado de Asturias, Spain
S Supporting Information
b
ABSTRACT: The cyclopentadienyl-containing complex [Ru(η5-C5H5)(MeCN){k3-
(P,C,C)-Ph2PCH2CHdCH2}][PF6] (1) reacts with allenes, giving regioselectively
the η2-allene complexes [Ru(η5-C5H5)(MeCN){k(P)-Ph2PCH2CHdCH2}(η2-
CH2dCdCR1R2)][PF6] [R1 = R2 = Me (3); R1 = H, R2 = Ph (4); R1R2 = ꢀ(CH2)5ꢀ
(5)]. On the other hand, the reaction of the pentamethylcyclopentadienyl-containing
complex [Ru(η5-C5Me5)(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}][OTf] (2) with
allenes yields regio- and stereoselectively the complexes [Ru(η5-C5Me5){k(P),η4-
Ph2PCH2CHdCHC(R1R2)CHdCH2}][OTf] [R1 = R2 = Me (6); R1 = H, R2 = Ph
(7); R1R2 = ꢀ(CH2)5ꢀ (8)] via the intermolecular coupling of allene and allyldiphe-
nylphosphine ligands. The intermediate complex [Ru(η5-C5Me5)(MeCN){k(P)-
Ph2PCH2CHdCH2}{η2-CH2dCdCMe2}][OTf] (9) has been spectroscopically
characterized. The structure of complex [Ru(η5-C5Me5){k(P),η4-Ph2PCH2CHdCHC-
(Me)2CHdCH2}][{3,5-(CF3)2C6H3}4B] (6a) has been resolved by X-ray diffraction
analysis.
’ INTRODUCTION
’ RESULTS AND DISCUSSION
Synthesis of the Complexes [Ru(η5-C5H5)(MeCN){j(P)-
Ph2PCH2CHdCH2}(η2-CH2dCdCR1R2)][PF6] (R1 = R2 = Me
(3); R1 = H, R2 = Ph (4); R1R2 = ꢀ(CH2)5ꢀ (5)). The complex
[Ru(η5-C5H5)(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}][PF6]
(1) reacts with allenes at room temperature in THF, afford-
ing complexes [Ru(η5-C5H5)(MeCN){k(P)-Ph2PCH2CHd
CH2}(η2-CH2dCdCR1R2)][PF6] (3ꢀ5), isolated as pale yel-
low solids in moderate-to-good yields (62ꢀ95%) (Scheme 1).
Complexes 3ꢀ5 should be kept under a nitrogen atmosphere at
low temperature to prevent decomposition. Characteristic features
of the spectroscopic data are the following: (i) The NMR spectra
(298 K) confirm the k(P) coordination mode of the allylpho-
sphine ligand.8a Thus, the 31P{1H} NMR spectra exhibit a singlet
Allenes are an important class of building blocks for modern
organic synthesis through metal-catalyzed reactions.1 In the last
years, some inter- and intramolecular reactions of allenes with
unsaturated compounds have been efficiently undertaken using
several ruthenium catalysts. Thus, Ma and Jia have reported the
synthesis of 2-vinyl-1,3-cycloalkadienes by intermolecular reac-
tions of cyclic allenes with terminal alkynes,2 while Trost et al.
have studied the intermolecular cyclometalation of several
functionalized monosubstituted allenes with α,β-unsaturated
enones.3 On the other hand, Ihara et al. have observed that the
complex [Ru(η5-C5H5)(MeCN)3][PF6] catalyzes dimerization
of allenic alcohols.4 Intramolecular ruthenium-catalyzed (2 + 2)
cycloaddition reactions of allenes5 and of allenynes,6 and cyclo-
isomerization of δ-enallenes to form 1,3- or 1,4-cyclic dienes7
have been also reported. In most cases, a η2-allene intermediate
was proposed, although no experimental evidence of its formation
could be provided. Continuing our interest in the CꢀC coupling
reactions between alkenylphosphinesꢀruthenium complexes and
alkynes,8 we now report our studies on the reactivity of complexes
[Ru(η5-C5R5)(MeCN){k3(P,C,C0)-Ph2PCH2CHdCH2}][PF6]
(R1 = H (1); R2 = Me (2)) toward allenes. It should be noted that
few examples of stoichiometric Ru-assisted coupling reactions have
been reported up to now.9 Moreover, studies on the stoichiometric
coupling reactions of allenes with unsaturated substrates would
be helpful for a better mechanistic understanding of transition-
metal-catalyzed reactions of allenes.
1
signal at 42.3 (3), 40.6 (4), and 42.1 (5) ppm; the H NMR
spectra show a broad singlet (dCH2, 5.16ꢀ5.10 ppm) and a
multiplet (dCH, 5.62ꢀ5.51 ppm); and a single C{1H} NMR
resonance at 120.6 (t, 3JCP = 10.6 Hz) (3), 121.6 (t, 3JCP = 11.4 Hz)
(4), and 120.6 (t, 3JCP = 10.9 Hz) ppm (5) is observed for the
methylene carbon dCH2. (ii) The NMR spectra show a singlet
in the range of 2.48ꢀ2.22 ppm (1H NMR) and of 5.2ꢀ4.0 ppm
(13C{1H} NMR) for the methyl group of acetonitrile. (iii) The
13C{1H} NMR spectra of complexes show single resonances
for the allene carbon nuclei: terminal sp2-CH2 (10.3, 18.4, and
Received: July 22, 2011
Published: October 12, 2011
r
2011 American Chemical Society
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Scheme 1
Scheme 2
Figure 2
Figure 1
unsuccessful. Thus, warming solutions of complexes 3ꢀ5 in
refluxing THF resulted in mixtures of unidentified products.
Synthesis of the Complexes [Ru(η5-C5Me5){j(P),η4-Ph2-
PCH2CHdCHC(R1R2)CHdCH2}][OTf] (R1 = R2 = Me (6); R1 =
H, R2 = Ph (7); R1R2 = ꢀ(CH2)5ꢀ (8)). In contrast to the above
results, when the allene partners were treated with the penta-
methylcyclopentadienyl-containing complex [Ru(η5-C5Me5)-
(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}][OTf] (2) in reflux-
ing THF, the complexes [Ru(η5-C5Me5){k(P),η4-Ph2PCH2CHd
CHC(R1R2)CHdCH2}][OTf] (6ꢀ8) were formed in a regio-
and stereoselective manner. Compounds 6ꢀ8 were isolated as
orange air-stable solids in good yield (76ꢀ96%) (Scheme 2).
The most significant spectroscopic data are the following: (i)
The IR spectra show the expected absorptions for the OTfꢀ
anion (ca. 1264, 1150, 1030 cmꢀ1). (ii) The 31P{1H} NMR spec-
tra exhibit a characteristic high-field singlet at ꢀ60.9 (6), ꢀ60.9
(7), and ꢀ60.8ppm (8).14 (iii) The 1H NMR spectra show signals
for the olefinic protons of both η2-alkenes (see the P-hexa-2,5-
dien-1-yl substituent) in the ranges of 4.12ꢀ4.02 (H-2), 2.98ꢀ
2.84(H-5), 2.20ꢀ1.77(H-3), and 2.57ꢀ2.31 and 1.53ꢀ1.39 (2 ꢁ
H-6) ppm (see Figure 2). (iv) The 13C{1H} NMR spectra show
singlet signals for the terminal olefinic carbons (C-6, 52.6ꢀ49.1
ppm; C-5, 47.8ꢀ38.8 ppm) and doublet signals for the internal
9.7 ppm for 3, 4, and 5, respectively), central carbon sp-C (149.7,
160.2, and 147.3 ppm for 3, 4, and 5, respectively), and terminal
sp2-CHR/CR2 (117.5, 120.9, and 124.9 ppm for 3, 4, and 5,
respectively). The high- and low-field signals observed for the
CH2 and the central carbons of the allene moiety, respectively,
indicate that the coordination to ruthenium occurs through
the unsubstituted double bond of the allene. These data are in
good agreement with those reported for other η2-alleneꢀmetal
complexes.10,11
The high regio- and diasteroselectivity of these reactions repre-
sents the most interesting feature. Although it has been reported that
metal allene complexes undergo two fluxional processes, rotation of
the allene ligand about the metalꢀallene bond and migration of the
metallic fragment along the orthogonal allene π-systems,10c,11d,12
the NMR spectra of complexes 3ꢀ5 show the presence of a unique
isomer. Thus, the presence of a single isomer for complex 3 at room
temperature is evidenced by the observation of a singlet (42.3 ppm,
31P NMR) and two methyl resonances (2.15 and 2.03 ppm,
1H NMR; 28.2 and 22.5 ppm, 13C NMR). Moreover, no evidence
of a fluxional processes is observed on the NMR time scale in the
range of 298ꢀ213 K. The cross-peak (2D, NOESY) between a
methyl group and the cyclopentadienyl ligand indicates the spatial
proximity of both groups (Figure 1), thus confirming the syn
orientation of the methyl group toward the ruthenium center.
The stereochemistry of the double bond in the case of 4 could
not be established on the basis of NOESY experiments. Tentatively,
the structure of 4 has been assigned as the isomer with the Ph group
anti to the ruthenium center on the basis of the 1H NMR shift of the
benzylidene hydrogen (CdCHPh) and is in accordance with the
steric effects reported in the literature.11d,12a,12b,13 Unfortunately, an
X-ray analysis could not be performed because all attempts to
crystallize complexes 3ꢀ5 have been unsuccessful.
olefinic carbons C-2 and C-3 (C-2/C-3, 57.5ꢀ47.9 ppm; 2JCP
19.8ꢀ19.6 Hz, 3JCP = 8.2ꢀ7.9 Hz).
=
All the attempts to obtain single crystals of complexes 6ꢀ8
suitable for X-ray analysis failed. However, slow diffusion of
hexane into an ethereal solution of complex [Ru(η5-C5Me5){k-
(P),η4-Ph2PCH2CHdCHCMe2CHdCH2}][{3,5-(CF3)2C6H3}4B]
(6a) (obtained from 6 via TfOꢀ/3,5-(CF3)2C6H3}4Bꢀ anion
exchange using the Brookhart’s salt15) allowed us to collect
suitable crystals for X-ray diffraction studies.
X-ray Crystal Structure of the Complex 6a. An ORTEP-type
representation of the cation of complex 6a is shown in Figure 3.
Selected bonding data are collected in Table 1. The crystal
belongs to the centrosymmetric space group P1, indicating the
presence of a racemic mixture. The asymmetric unit consists of
two molecules with the same absolute configuration. Because the
more relevant structural parameters are similar in both mole-
cules, only a single data set is discussed. Figure 3 shows the
The alkeneꢀallene exchange process from the complex [Ru-
(η5-C5H5)(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}][PF6] (1)
leading to 3ꢀ5 reflects the well-known hemilabile character of
the allyldiphenylphosphine,8 a fact that has been corroborated by
kinetic studies.8c
Further attempts directed to promote the coupling of the
unsaturated ligands within the metal coordination sphere were
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ARTICLE
Figure 4
Scheme 3
Figure 3. ORTEP drawing of complex 6a showing atom-labeling scheme.
Thermal ellipsoids are shown at 10% probability. Hydrogen atoms and the
[{3,5-(CF3)2C6H3}4B] anion are omitted for clarity. Only the Cipso-aryl of
the PPh3 ligand is drawn.
Table 1. Selected Bond Distances (Å) and Angles (deg) for
Complex 6a 0.25C6H14
3
bond
distance
bond
distance
Ru(1)ꢀC*a
Ru(1)ꢀP(1)
Ru(1)ꢀC(1)
Ru(1)ꢀC(2)
C(2)ꢀC(3)
1.8703(6)
2.3178(15)
2.245(6)
Ru(1)ꢀC(4)
Ru(1)ꢀC(5)
C(1)ꢀC(2)
C(4)ꢀC(5)
C(3)ꢀC(4)
2.302(6)
2.308(5)
1.354(9)
1.365(9)
1.515(9)
2.243(6)
1.543(10)
with two less-intense signals corresponding to complexes 2 (ꢀ54.6
ppm) and 6 (ꢀ60.9 ppm). The analysis of the NMR (1H, 31P, 13C)
spectra of this mixture allowed the spectroscopic characterization of
complex 9 (see the Experimental Section). When the reaction
mixture is kept at room temperature during several hours, increasing
of the amount of 6 and the total disappearance of 2 and 9 were
observed. Unlike complexes 3ꢀ5 (see above), variable-temperature
31P{1H} NMR studies (298ꢀ213 K) confirm the dynamic behavior
of complex 9 in solution. Thus, the broad resonance signal
(38.1 ppm) observed at room temperature splits at low temperature
(213 K) into three singlets (41.2, 38.4, and 35.9 ppm; relative
intensity, 5:2:1) corresponding with species with k(P)-coordination
of the alkenylphosphine ligand. It is conceivable that two distinct,
typical dynamic processes of η2-allene complexes (metalꢀolefin
rotation and orthogonal 1,2,2-shift of the organometallic fragment)12
take place at room temperature (see Figure 4).
A plausible reaction mechanism for the formation of com-
plexes 6ꢀ8 is shown in Scheme 3. The process would initiate by
generation of a coordination vacancy by dissociation of the coor-
dinated olefin group of allylphosphine ligand, followed by metalꢀη2
allene coordination to give complex (A). Once the allene is coor-
dinated, the dissociation of the acetonitrile and recoordination of
the olefin group of allylphosphine would give the coordination
complex (B). This intermediate species would undergo an
oxidative cyclometalation to provide the ruthenacyclopentene
intermediate (C), which would form the final complex (D) via a
β-hydride elimination/reductive elimination sequence. The ob-
served regiochemistry (see X-ray structure) implies that, among
the species participating in the fluxional process (see Figure 4),
onlythecomplexwiththemetalcoordinatedtothemoresubstituted
angle
value
angle
value
C(1)ꢀC(2)ꢀC(3)
C(2)ꢀC(3)ꢀC(4)
C(5)ꢀC(6)ꢀP(1)
C*ꢀRu(1)ꢀC(5)
C*ꢀRu(1)ꢀC(4)
125.5(6)
97.7(5)
C(3)ꢀC(4)ꢀC(5)
C(4)ꢀC(5)ꢀC(6)
C*ꢀRu(1)ꢀP(1)
C*ꢀRu(1)ꢀC(1)
C*ꢀRu(1)ꢀC(2)
131.3(6)
72.6(3)
93.5(4)
127.32(4)
127.73(19)
119.67(18)
135.06(15)
126.45(18)
a CT01 = C* = centroid of C(21), C(22), C(23), C(24), C(25).
enantiomer with configuration S at the ruthenium center and the
terminal olefin being coordinated through the re-face.
Complex 6a exhibits a three-legged piano stool geometry with
the ruthenium atom bonded to the cyclopentadienyl ring and to
the tridentate ligand, (Z)-(4,4-dimethylhexa-2,5-dien-1-yl)diphenyl-
phosphine. The bond distances around the ruthenium atom are
in accordance with previously reported structures.8a Thus, the
Ru(1)ꢀC(1) (2.245(6) Å), Ru(1)ꢀC(2) (2.243(6) Å), Ru-
(1)ꢀC(4) (2.302(6), and Ru(1)ꢀC(5) (2.308(5) Å) bond dis-
tances as well as the C(1)ꢀC(2) (1.354(9) Å) and C(4)ꢀC(5)
(1.365(9) Å) olefinic bond distances reflect the coordination of the
two olefins of this pentadiene fragment to the ruthenium center.
The formation of an η2-allene intermediate complex [Ru
(η5-C5Me5)(MeCN){k(P)-Ph2PCH2CHdCH2}(η2-CH2dCd
CMe2)][OTf] (9) is assessed by 31P{1H} NMR monitoring the
reaction of 2 with 1,1-dimethylallene in CDCl3. After 1 h at 298 K,
the 31P{1H} NMR spectrum of the reaction mixture shows a
broad signal at 38.1 ppm, confirming the k(P) coordination
mode of the allylphosphine ligand in the new complex 9, along
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CdC moiety of the allene (complex A, scheme 3) behaves as the
productive species.
3.41 (m, 1H, dCH2), 3.09 (m, 1H, P-CH2), 2.76 (m, 1H, dCH2), 2.16
(s, 3H, CH3), 1.49 (s, 15 H, C5Me5). 31P{1H} NMR (121.49 MHz,
CD2Cl2, 293 K): δ = ꢀ54.6 (s). 13C{1H} NMR (75.48 MHz, acetone-d6,
293 K): δ = 132.5ꢀ129.0 (CN, Ph), 121.0 (q, JCF = 320.3 Hz,
CF3SO3), 93.4 (s, C5Me5), 60.1 (d, JCP = 7.0 Hz, =CH2), 50.7 (d, JCP
= 22.5 Hz, dCH), 34.6 (d, JCP = 33.8 Hz, P-CH2), 9.1 (s, C5Me5), 4.1
(s, CH3).
’ SUMMARY
The ruthenium-assisted coupling reaction of allenes with
tethered CdC double bonds of the allyldiphenylphosphine ligand
in the complex [Ru(η5-C5Me5)(MeCN){k3(P,C,C)-Ph2PCH2CHd
CH2}][OTf] (2) yields the complexes [Ru(η5-C5Me5){k-
(P),η4-Ph2PCH2CHdCHC(R1R2)CHdCH2}][OTf] [R1 =
R2 = Me (6); R1 = H, R2 = Ph (7); R1R2 = ꢀ(CH2)5ꢀ (8)] in a
regio- and stereoselective manner. The η2-allene complex inter-
mediate [Ru(η5-C5Me5)(MeCN){k(P)-Ph2PCH2CHdCH2}-
(η2-CH2dCdCMe2)][OTf] (9) has been detected by NMR
spectroscopy, and a plausible reaction mechanism for the for-
mation of complexes 6ꢀ8 is proposed. Moreover, the η2-allene
complexes [Ru(η5-C5H5)(MeCN){k(P)-Ph2PCH2CHdCH2}-
(η2-CH2dCdCR1R2)][PF6] [R1 = R2 = Me (3); R1 = H, R2 =
Ph (4); R1R2 = ꢀ(CH2)5ꢀ (5)] are exclusively isolated using the
complex [Ru(η5-C5H5)(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}]-
[PF6] (1) as a precursor.
Synthesis of the Complexes [Ru(η5-C5H5)(MeCN){j(P)-
Ph2PCH2CHdCH2}{η2-CH2dCdCR1R2}][PF6] (R1 = R2 = Me
(3); R1 = H, R2 = Ph (4); R1R2 = ꢀ(CH2)5ꢀ (5). The corresponding
allene (0.3 mmol) was added to a solution of the complex [Ru(η5-
C5H5)(MeCN){k3(P,C,C)-Ph2PCH2CH2CHdCH2}][PF6] (116 mg,
0.2 mmol) in THF (10 mL). The resulting solution was stirred at room
temperature for 2 h. The solution was then concentrated to ca. 3 mL, and
a mixture of diethyl ether/hexane (1:1, 30 mL) was added. The resulting
pale yellow solid was washed with diethyl ether (2 ꢁ 10 mL) and
vacuum-dried. (3) Yield: 0.123 g, 95%. IR (KBr, ν(PF6), cmꢀ1): 838 (s).
ΛM = 116 S cm2 molꢀ1 (acetone, 293 K). MS-MALDI: m/z 461
([Ru(C5H5)(Ph2PCH2CHdCH2)(CH2dCdCMe2)]+). 1H NMR
(300.13 MHz, CD2Cl2, 293 K): δ = 7.69ꢀ7.23 (m, 10H, Ph), 5.54 (m,
1H, dCH), 5.10 (m, 2H, dCH2), 4.95 (s, 5H, C5H5), 3.40 (m, 2H,
P-CH2), 2.49 (m, 2H, CH2‑allene), 2.22 (s, 3H, CH3CN), 2.15 (s, 3H,
CH3‑anti), 2.03 (s, 3H, CH3‑syn) ppm. 31P{1H} NMR (121.49 MHz,
CD2Cl2, 293 K): δ = 42.3 (s) ppm. 13C{1H} NMR (75.48 MHz, CDCl3,
293 K): δ = 149.7 (s, CdCMe2), 133.1ꢀ128.8 (dCH, CN, Ph), 120.6
(d, 3JCP = 10.6 Hz, dCH2), 117.5 (s, CdCMe2), 86.0 (s, C5H5), 36.9 (d,
JCP = 28.2 Hz, P-CH2), 28.2 (s, CH3‑anti), 22.5 (s, CH3‑syn), 10.3 (broad,
CH2‑allene), 4.0 (s, CH3CN) ppm. (4) Yield: 0.130 g, 94%. IR (KBr,
ν(PF6), cmꢀ1): 839 (s). ΛM = 107 S cm2 molꢀ1 (acetone, 293 K). MS-
MALDI: m/z509([Ru(C5H5)(Ph2PCH2CHdCH2)(CH2dCdCHPh)]+).
1H NMR (300.13 MHz, CD2Cl2, 293 K): δ = 7.56ꢀ7.21 (m, 15H, Ph),
6.26 (broad, dCHPh), 5.51 (m, 1H, dCH), 5.22 (s, 5H, C5H5), 5.14
(m, 2H, dCH2), 3.37ꢀ3.18 (m, 3H, P-CH2, CH2‑allene), 2.53 (m, 1H,
CH2‑allene), 2.48 (s, 3H, CH3CN) ppm. 31P{1H} NMR (121.49 MHz,
CD2Cl2, 293 K): δ = 40.6. 13C{1H} NMR (75.48 MHz, CD2Cl2, 293 K):
δ = 160.2 (s, CdCHPh), 138.0 (s, Cipso Ph), 133.5ꢀ127.1 (dCH,
Ph, CN), 121.6 (d, 3JCP = 11.4 Hz, dCH2), 120.9 (s, CdCHPh), 88.7 (s,
C5H5), 36.0 (d, JCP = 28.7 Hz, P-CH2), 18.4 (broad, CH2‑allene), 5.2 (s,
CH3CN) ppm. (5) Yield: 0.085 g, 62%. IR (KBr, ν(PF6), cmꢀ1): 834.
ΛM = 118 S cm2 molꢀ1 (acetone, 293 K). MS-MALDI: m/z 501
([Ru(C5H5)(Ph2PCH2CHdCH2)(CH2dCdC(CH2)5))]+). 1H NMR
(300.13 MHz, CD2Cl2, 293 K): δ = 7.60ꢀ7.33 (m, 10H, Ph), 5.62 (m,
1H, dCH), 5.16 (m, 2H, dCH2), 4.99 (s, 5H, C5H5), 3.45 (m, 2H,
P-CH2), 2.56 (m, 4H, ꢀ(CH2)5ꢀ), 2.27 (s, 3H, CH3CN), 2.13 (m, 2H,
CH2‑allene), 1.71ꢀ1.58 (m, 6H, ꢀ(CH2)5ꢀ) ppm. 31P{1H} NMR
(121.49 MHz, CD2Cl2, 293 K): δ = 42.1 (s) ppm. 13C{1H} NMR
(75.48 MHz, CD2Cl2, 293 K): δ = 147.3 (s, CdCH(CH2)5),
133.7ꢀ128.4 (dCH, Ph, CN), 124.9 (s, CdCH(CH2)5), 120.6 (d,
3JCP = 10.9 Hz, dCH2), 86.0 (s, C5H5), 40.5 (s, ꢀ(CH2)5ꢀ), 36.9 (d,
JCP = 26.7 Hz, P-CH2), 33.9, 28.6, 28.5, 26.5 (4s, ꢀ(CH2)5ꢀ), 9.7
(broad, CH2‑allene), 4.1 (s, CH3CN) ppm.
’ EXPERIMENTAL SECTION
General Procedures. All manipulations were performed under an
atmosphere of dry nitrogen using vacuum-line and standard Schlenk
techniques. Solvents were dried by standard methods and distilled under
nitrogen before use. The compounds [Ru(η5-C5Me5)(MeCN)3]-
[OTf]16 [Ru(η5-C5H5)(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}]-
[PF6] (1)14 and Ph2PCH2CHdCH2 were prepared by previously
17
reported methods. Other reagents were obtained from commercial
suppliers and used without further purification. Infrared spectra were
recorded on a PerkinElmer 1720-XFT spectrometer. The C, H, and N
analyses were carried out with a PerkinElmer 240-B microanalyzer. A
correct elemental analysis could not be obtained for complexes 3ꢀ5,
probably as a consequence of their high air sensitivity. The conductivities
were measured at room temperature, in acetone solutions (ca. 5 ꢁ 10ꢀ4 M),
with a Jenway PCM3 conductimeter. Mass spectra (FAB) were recorded
using a VG-AUTOSPEC spectrometer, operating in the positive mode,
and using 3-nitrobenzyl alcohol (NBA) as the matrix. Mass spectra
(MALDI-TOF) were determined with a MICROFLEX Bruker spectrom-
eter, operating in the positive mode, and using dihydroxyanthranol
as the matrix. NMR spectra were recorded on Bruker spectrometers
(AC400 operating at 400.13 (1H), 100.61 (13C) and 161.95 (31P) MHz
or 300 DPX or AC300 operating at 300.13 (1H), 75.48 (13C), and
121.49 (31P) MHz). DEPT experiments were carried out for all the
compounds. 2D-NMR (NOESY, HSQC) were performed in selected
complexes. Chemical shifts are reported in parts per million and
referenced to TMS or 85% H3PO4 as standards. Coupling constants
J are given in hertz. Figure 2 shows the atom labels used for the 1H and
13C{1H} spectroscopic data of complexes 6ꢀ8.
Synthesis of the Complex [Ru(η5-C5Me5)(MeCN){j3(P,C,
C)-Ph2PCH2CHdCH2}][OTf] (2). Allyldiphenylphosphane (116 μL,
0.54 mmol) was added to a solution of the complex [Ru(η5-C5Me5)-
(MeCN)3][OTf] (250 mg, 0.49 mmol) in CH2Cl2 (25 mL) at 0 °C. The
resulting solution was stirred for 0.75 h. The solution was then
concentrated to ca. 3 mL, and a mixture of diethyl ether/hexane (1:1,
30 mL) was added. The resulting yellow solid was washed with diethyl
ether/hexane (1:1, 2 ꢁ 30 mL) and vacuum-dried. Yield: 256 mg, 80%.
IR (Nujol, ν(CN), ν(OTf) cmꢀ1): 2288 (w), 1264 (vs), 1151 (m), 1031
(s). Molar conductivity (acetone, S cm2 molꢀ1, 293 K): 99. Anal. Calcd
for C28H33F3NO3PRuS (652.67 g/mol): C, 51.53; H, 5.10; N, 2.15.
Found: C, 50.93; H, 4.89; N, 1.97. 1H NMR(300.13 MHz, CD2Cl2, 293 K):
δ = 7.33 (m, 10H, Ph), 4.32 (m, 1H, P-CH2), 3.63 (m, 1H, dCH),
Synthesis of the Complexes [Ru(η5-C5Me5){j(P),η4-
Ph2PCH2CHdCHC(R1R2)CHdCH2}][OTf] (R1 = R2 = Me (6);
R1 = H, R2 = Ph (7); R1R2 = ꢀ(CH2)5ꢀ (8)). The allene (0.17 mmol)
was added to a solution of the complex [Ru(η5-C5Me5)(MeCN){k3(P,
C,C)-Ph2PCH2CH2CHdCH2}][OTf] (100 mg, 0.15 mmol) in THF
(10 mL). The mixture was heated at 60 °C for 1 h in a sealed tube. The
solution was then evaporated to dryness, the crude product extracted
with dichloromethane, and the extract filtered. Concentration of the
resulting solution to ca. 3 mL, followed by addition of a mixture of
diethyl ether/hexane (1:1, 30 mL), afforded complexes 6ꢀ8 as orange
solids, which were washed with diethyl ether (2 ꢁ 5 mL) and vacuum-
dried. (6) Yield: 0.097 g, 96%. IR (KBr, ν(OTf), cmꢀ1): 1264 (vs), 1149
(vs), 1031 (vs). ΛM = 113 S cm2 molꢀ1 (acetone, 293 K). Anal. Calcd for
5806
dx.doi.org/10.1021/om200668h |Organometallics 2011, 30, 5803–5808

Organometallics
ARTICLE
C31H38F3O3PRuS (679.74 g/mol): C, 54.78; H, 5.63. Found: C,
54.90; H, 5.76. MS-MALDI: m/z 531 ([Ru(C5Me5)(Ph2PCH2CHd
CHCMe2CHdCH2)]+). 1H NMR (300.13 MHz, CDCl3, 293 K): δ =
7.57ꢀ7.39 (m, 10H, Ph), 4.13 (m, 1H, H-1), 4.02 (m, 1H, H-2), 3.12
(m, 1H, H-1), 2.98 (m, 1H, H-5), 2.31 (d, JHH = 8.4 Hz, 1H, H-6), 2.20
(m, 1H, H-3), 1.53 (m, 1H, H-6), 1.51 (s, 15H, C5Me5), 1.48 (s, 3H,
CH3), 0.78 (s, 3H, CH3) ppm. 31P{1H} NMR (121.49 MHz, CDCl3,
293 K): δ = ꢀ60.9 ppm. 13C{1H} NMR (75.48 MHz, CDCl3, 293 K):
δ = 132.9ꢀ129.2 (Ph), 121.1 (q, JCF = 320.6 Hz, CF3SO3), 95.6 (s,
C5Me5), 57.5 (d, JCP = 8.2 Hz, C-3), 56.5 (d, JCP = 19.8 Hz, C-2), 49.8 (s,
C-6), 47.8 (s, C-5), 34.0 (s, CH3), 32.2 (s, C-4), 28.1 (d, JCP = 34.2 Hz,
C-1), 23.7 (s, CH3), 9.2 (s, C5Me5) ppm. (7) Yield: 0.083 g, 76%. IR
(KBr, ν(OTf), cmꢀ1): 1264 (vs), 1150 (m) and 1030 (vs). ΛM = 101
Table 2. Crystal Data and Refinement for 6a 0.25C6H14
3
chem formula
C63.5H53.5BF24PRu
fw
2830.83
T (K)
293(2)
wavelength (Å)
cryst syst
space group
a (Å)
1.5418
triclinic
P1
12.868(2)
b (Å)
21.135(4)
c (Å)
25.841(9)
α (deg)
β (deg)
γ (deg)
V (Å3)
107.61(2)
S cm2 molꢀ1 (acetone, 293 K). Anal. Calcd for C35H38F3O3PRuS
3
96.99(2)
CH2Cl2 (727.78 g/mol): C, 53.20; H, 4.96. Found: C, 53.30; H, 4.39.
MS-MALDI: m/z 579 ([Ru(C5Me5)(Ph2PCH2CHdCHCHPhCHd
CH2)]+). 1H NMR (300.13 MHz, CD2Cl2, 293 K): δ = 7.59ꢀ7.08 (m,
15H, Ph), 4.43 (m, 1H, H-1), 4.12 (m, 1H, H-2), 2.97 (m, 2H, H-5,
H-1), 2.65 (m, 1H, H-4), 2.57 (d, JHH = 6.5 Hz, 1H, H-6), 1.77 (m, 1H,
H-3), 1.50 (s, 15H, C5Me5), 1.39 (m, 1H, H-6) ppm. 31P{1H} NMR
(121.49 MHz, CDCl3, 293 K): δ = ꢀ60.9 ppm. 13C{1H} NMR (75.48
MHz, CDCl3, 293 K): δ = 141.6ꢀ126.1 (Ph), 120.1 (q, JCF = 321.0 Hz,
CF3SO3), 95.8 (s, C5Me5), 55.0 (d, JCP = 19.6 Hz, C-2), 52.6 (s, C-6),
104.684(16)
6328(3)
Z
4
F
calcd (g cmꢀ3
)
1.486
μ (mmꢀ1
)
3.231
F(000)
2858
cryst size (mm3)
θ range (deg)
index ranges
0.22 ꢁ 0.16 ꢁ 0.1
3.41ꢀ74.91
ꢀ14 e h e 15
ꢀ25 e k e 26
ꢀ31 e l e 31
78915
47.9 (d, JCP = 7.9 Hz, C-3), 39.7, 38.8 (2s, C-4, C-5), 27.6 (d, JCP
=
34.2 Hz, C-1), 9.2 (s, C5Me5), ppm. (8) Yield: 0.095 g, 88%. IR (KBr,
ν(OTf), cmꢀ1): 1264 (vs), 1151 (vs) and 1031 (s). ΛM = 111 S cm2 molꢀ1
(acetone, 293 K). Anal. Calcd for C34H42F3O3PRuS (719.80 g/mol): C,
56.73; H, 5.63. Found: C, 56.50; H, 5.78. MS-MALDI: m/z 571
([Ru(C5Me5){Ph2PCH2CHdCHC(ꢀ(CH2)5ꢀ)CHdCH2}]+). 1H
NMR (300.13 MHz, CD2Cl2, 293 K): δ = 7.60ꢀ7.45 (m, 10H, Ph),
4.20 (m, 1H, H-1), 4.02 (m, 1H, H-2), 3.10 (m, 1H, H-1), 2.84 (m, 1H,
H-5), 2.34 (d, JHH = 6.3 Hz, 1H, H-6), 2.06 (m, 1H, H-3), 1.97 (broad,
2H, ꢀ(CH2)5ꢀ), 1.76 (broad, 8H, ꢀ(CH2)5ꢀ), 1.50 (broad, 16H,
C5Me5, H-6) ppm. 31P{1H} NMR (121.49 MHz, CDCl3, 293 K):
δ = ꢀ60.8 ppm. 13C{1H} NMR (75.48 MHz, CDCl3, 293 K): δ = 133.0ꢀ
129.4 (Ph), 121.0 (q, JCF = 321.0 Hz, CF3SO3), 95.6 (s, C5Me5), 57.0,
56.8 (2 ꢁ br s, C-2, C-3), 49.1 (s, C-6), 47.0 (s, C-5), 42.6 (s, ꢀ(CH2)5ꢀ),
37.4 (s, C-4), 31.7 (s, ꢀ(CH2)5ꢀ), 28.5 (d, JCP = 34.0 Hz, C-1), 25.7,
21.3, 20.3 (3s, ꢀ(CH2)5ꢀ), 9.4 (s, C5Me5) ppm.
no. of reflns collected
no. of independent reflns
completeness to θ = 74.91° (%)
refinement method
25 038 [R(int) = 0.0283]
96.2
full-matrix least-squares on F2
25 038/0/1601
1.118
data/restraints/parameters
GOF on F2
R1 [I > 2σ(I)]a
R1 = 0.0779, wR2= 0.2382
R1 = 0.0949, wR2 = 0.2620
1.259 and ꢀ0.723
R (all data)
largest diff. peak and hole (e Åꢀ3
a R1 = ∑(|Fo| ꢀ |Fc|)/∑|Fo|; wR2 = {∑[w(Fo ꢀ Fc2)2]/∑[w(Fo ) ]}1/2
)
2
2 2
.
Synthesis and Spectroscopic Characterization of Complex
[Ru(η5-C5Me5)(MeCN){j(P)-Ph2PCH2CHdCH2}{η2-CH2dCd
CMe2}][OTf] (9). To an NMR tube containing the complex [Ru(η5-
C5Me5)(MeCN){k3(P,C,C)-Ph2PCH2CHdCH2}][OTf] (1) (0.060 g,
0.09 mmol) dissolved in 0.5 mL of CDCl3 at room temperature was
added 3-methyl-1,2-butadiene (32 μL, 0.18 mmol). After 1 h at room
temperature, the complex [Ru(η5-C5Me5)(MeCN){k(P)-Ph2PCH2CHd
CH2}{η2-CH2dCdCMe2}][OTf] (9) was formed as majority product
and characterized by NMR spectroscopy: 1H NMR (300.13 MHz,
CDCl3, 293 K): δ = 7.55ꢀ7.20 (m, 10H, Ph), 5.43 (m, 1H, dCH),
5.00 (m, 2H, dCH2), 3.18 (m, 2H, P-CH2), 2.63 (s, 3H, CH3CN), 2.33
(m, 2H, CH2‑allene), 2.27 (s, 3H, CH3‑anti), 1.97 (s, 3H, CH3‑syn), 1.39 (s,
15H, C5Me5) ppm. 31P{1H} NMR (121.49 MHz, CDCl3, 293 K): δ =
38.1 (broad) ppm. 13C{1H} NMR (75.48 MHz, CDCl3, 293 K): δ =
158.5 (s, CdCMe2), 133.4ꢀ129.1 (dCH, Ph), 121.5 (q, JCF = 320.6
Hz, CF3SO3), 120.5 (d, 3JCP = 9.9 Hz, dCH2), 116.3 (s, CN), 98.1 (s,
C5Me5), 96.1 (s, CdCMe2), 35.0 (d, JCP = 25.8 Hz, P-CH2), 30.5 (s,
CH3‑anti), 22.0 (s, CH3‑syn), 17.4 (s, CH2‑allene), 9.7 (s, C5Me5), 5.2 (s,
CH3CN).
single-crystal diffractometer, using CuꢀKα radiation (λ = 1.5418 Å).
Images were collected at a 65 mm fixed crystalꢀdetector distance, using
the oscillation method, with 1° oscillation and a variable exposure time
per image (1.5ꢀ2s). The data collection strategy was calculated with the
program CrysAlis Pro CCD.18 Data reduction and cell refinement were
performed with the program CrysAlis Pro RED.18 An empirical absorp-
tion correction was applied using the SCALE3 ABSPACK algorithm as
implemented in the program CrysAlis Pro RED.18
The software package WINGX was used for space group determina-
tion, structure solution, and refinement.19 The structure was solved by
Patterson intepretation and phase expansion using DIRDIF.20 Isotropic
least-squares refinement on F2 using SHELXH97 was performed.21
During the final stages of the refinements, all the positional parameters
and the anisotropic temperature factors of all the non-H atoms were
refined except some highly disordered fluorine (these atoms were found
in two positions and isotropically refined). The H atoms were geome-
trically placed, and their coordinates were refined riding on their parent
2
2
atoms. The function minimized was ([∑wFo ꢀ Fc2)/∑w(Fo )]1/2
,
where w = 1/[σ2(Fo2) + (aP)2 + bP] (a = 0.1635, b = 3.5661)
X-ray Diffraction. Suitable crystals for X-ray diffraction analysis
were obtained by slow diffusion of hexane into a saturated solution of the
complex 6a in dichloromethane. In the asymmetric unit of complex 6a,
half a hexane molecule per two formula units of the complex was found.
The most relevant crystal and refinement data are collected in Table 2.
Diffraction data were recorded on an Oxford Diffraction Xcalibur Nova
with σ(Fo ) from counting statistics and P = (Max (Fo , 0) + 2Fc2)/3.
Atomic scattering factors were taken from the International Tables
for X-ray Crystallography International.22 Geometrical calculations
were made with PARST.23 The crystallographic plots were made with
PLATON.24
2
2
5807
dx.doi.org/10.1021/om200668h |Organometallics 2011, 30, 5803–5808

Organometallics
ARTICLE
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Supporting Information. CIF/PLATON report, CIF
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’ AUTHOR INFORMATION
Corresponding Author
*E-mail: pgb@uniovi.es (M.P.G), elb@uniovi.es (E.L.).
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This work was supported by the Ministerio de Educaciꢀon y
Ciencia of Spain (Projects BQU2003-00255, CTQ2006-08485,
and Consolider Ingenio 2010 (CSD2007-00006)). A.V. thanks
the Spanish Ministerio de Educaciꢀon y Ciencia for a Ph.D.
fellowship.
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5808
dx.doi.org/10.1021/om200668h |Organometallics 2011, 30, 5803–5808