Allenylidene/Alkenylcarbyne synthesis and reactivity in ruthenium complexes with monodentate phosphine ligands

Article abstract of DOI:10.1021/om801125f

An alternative reactivity mode of electron-rich allenylidene complexes via alkenylcarbyne species is reported for the first time in ruthenium complexes bearing monodentate phosphine ligands (triethylphos- phine). Allenylidene complexes have been prepared

Full text of DOI:10.1021/om801125f

1546
Organometallics 2009, 28, 1546–1557
Allenylidene/Alkenylcarbyne Synthesis and Reactivity in Ruthenium
Complexes with Monodentate Phosphine Ligands
Jose Angel Pino-Chamorro, Emilio Bustelo, M. Carmen Puerta, and Pedro Valerga*
Departamento de Ciencia de los Materiales e Ingenier´ıa Metalu´rgica y Qu´ımica Inorga´nica, Facultad de
Ciencias, UniVersidad de Ca´diz, 11510 Puerto Real (Ca´diz), Spain
ReceiVed NoVember 25, 2008
An alternative reactivity mode of electron-rich allenylidene complexes via alkenylcarbyne species is
reported for the first time in ruthenium complexes bearing monodentate phosphine ligands (triethylphos-
phine). Allenylidene complexes have been prepared and characterized from [Cp*RuCl(PEt3)2] and a series
of propargyl alcohols bearing different substituents (HCt CCRR′(OH), where R, R′ ) Ph, Ph; R ) H,
R′ ) p-MeO-C6H4, C6H5, p-F-C6H4). Alkenylcarbyne complexes are prepared by protonation of the
allenylidene precursors. The X-ray structures of one secondary allenylidene (R, R′ ) H, Ph) and one
alkenylcarbyne complex (R, R′ ) Ph, Ph) constitute the first examples for ruthenium complexes bearing
monodentate phosphine ligands. Neutral alkynyl, cationic γ-substituted vinylidene, and bicyclic carbene
complexes have been isolated and characterized as a result of the allenylidene/alkenylcarbyne reactivity
against anionic and neutral (protic and aprotic) nucleophiles. The cycloaddition products obtained by
double addition of 1,3-cyclohexanedione and resorcinol (benzene-1,3-diol) to both allenylidene double
bonds and the analysis of the effects of including electron-donor or -withdrawing groups in the allenylidene/
alkenylcarbyne reactivity are reported.
(a) The catalytic isomerization of propargylic alcohols into
R,ꢀ-unsaturated carbonyl compounds6 involves electrophilic
allenylidene intermediates. The process most likely takes places
through alkoxycarbene intermediates, which is supported by the
well-documented addition of RO-H bonds (water or alcohols)
across the allenylidene CRdCꢀ unit.7
Introduction
Allenylidene chemistry has provided a large contribution to
the field of metal-mediated transformations of organic ligands.1
Besides the chemical properties, the interest in organometallic
compounds containing linear unsaturated carbon chains (alle-
nylidene and higher cumulenes) comes also from their potential
application as one-dimensional molecular wires and nonlinear
optical materials (NLO).2
The unsaturated character of the cumulated double bonds
gives rise to a diverse reactivity involving the C3 unit as a
sequence of electrophilic and nucleophilic centers. 1,2-Additions
to the internal or external double bonds, 1,3-cycloadditions, and
their subsequent rearrangements are among the most interesting
processes.3 At difference with the corresponding free organic
species (allenes),4 the regioselectivity of the addition is usually
very high, being controlled by the electronic and steric properties
of the particular metal fragment.
(b) As the steric hindrance and the electron-donating proper-
ties of the auxiliary ligands increase, the allenylidene internal
double bond becomes less reactive compared to the external
one. An intramolecular OH addition to the Cꢀ-Cγ double bond
of an allenylidene intermediate is proposed for the tandem
(3) Cycloadditions: (a) Fischer, H.; Roth, G.; Reindl, D.; Troll, C. J.
Organomet. Chem. 1993, 454, 133. (b) Fischer, H.; Leroux, F.; Stumpf,
R.; Roth, G. Chem. Ber. 1996, 129, 1475. (c) Roth, G.; Reindl, D.; Gockel,
M.; Troll, C.; Fischer, H. Organometallics 1998, 17, 1393. (d) Crochet, P.;
Esteruelas, M. A.; Lo´pez, A. M.; Ruiz, N.; Tolosa, J. I. Organometallics
1998, 17, 3479. (e) Esteruelas, M. A.; Go´mez, A. V.; Lo´pez, A. M.; On˜ate,
E. Organometallics 1998, 17, 3567. (f) Esteruelas, M. A.; Go´mez, A. V.;
Lo´pez, A. M.; On˜ate, E.; Ruiz, N. Organometallics 1999, 18, 1606. (g)
Bernard, D. J.; Esteruelas, M. A.; Lo´pez, A. M.; Oliva´n, M.; On˜ate, E.;
Puerta, M. C.; Valerga, P. Organometallics 2000, 19, 4327. (h) Werner,
H.; Wiedemann, R.; Laubender, M.; Windmuller, B.; Steinert, P.; Gevert,
O.; Wolf, J. J. Am. Chem. Soc. 2002, 124, 6966. (i) Baya, M.; Buil, M. L.;
Esteruelas, M. A.; Lo´pez, A. M.; On˜ate, E.; Rodr´ıguez, J. R. Organome-
tallics 2002, 21, 1841. (j) Bertolasi, V.; Mantovani, N.; Marvelli, L.; Rossi,
R.; Bianchini, C.; de los R´ıos, I.; Peruzzini, M.; Akbayeva, D. N. Inorg.
Chim. Acta 2003, 344, 207. (k) D´ıez, J.; Gamasa, M. P.; Gimeno, J.; Lastra,
E.; Villar, A. Organometallics 2005, 24, 1410. (l) D´ıez, J.; Gamasa, M. P.;
Gimeno, J.; Lastra, E.; Villar, A. J. Organomet. Chem. 2006, 691, 4092.
(m) Mantovani, N.; Bergamini, P.; Marchi, A.; Marvelli, L.; Rossi, R.;
Bertolasi, V.; Ferretti, V.; de los R´ıos, I.; Peruzzini, M. Organometallics
2006, 25, 416.
The activation of propargylic alcohols is the most general
and direct access to allenylidenes.5 Reciprocally, allenylidene
complexes are described as key intermediates in selective
catalytic transformations of propargylic alcohols:
* Corresponding author. E-mail: pedro.valerga@uca.es.
(1) (a) Bruce, M. I. Chem. ReV. 1991, 91, 197. (b) Bruce, M. I. Chem.
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J. Inorg. Chem. 2001, 571. (d) Werner, H.; Ilg, K.; Lass, R.; Wolf, J. J.
Organomet. Chem. 2002, 661, 137. (e) Fischer, H.; Szesni, N. Coord. Chem.
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Chem. ReV. 2004, 248, 1585. (g) Cadierno, V.; Gamasa, M. P.; Gimeno, J.
Coord. Chem. ReV. 2004, 248, 1627. (h) Winter, R. F.; Za´lˇı, S. Coord.
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10.1021/om801125f CCC: $40.75
2009 American Chemical Society
Publication on Web 01/29/2009

Allenylidene/Alkenylcarbyne Synthesis and ReactiVity
Organometallics, Vol. 28, No. 5, 2009 1547
Scheme 1. Key Step for the Propargylic Substitution of
Alcohols via Allenylidene
cyclization/reconstitutive addition of propargyl alcohols with
allyl alcohols, catalyzed by [CpRuCl(PPh3)2].8
Neutral and some cationic allenylidene complexes bearing
especially basic coligands are deactivated toward nucleophilic
attacks, except for strong nucleophilic reagents (typically anionic
species). Alternatively, it has been shown that they can be
protonated at the ꢀ-carbon, providing a mild access to alkenyl-
carbyne complexes. This method has recently allowed the
preparation and characterization of a number of alkenylcarbyne
ruthenium complexes,9 which have provided new insights into
the structure and reactivity of terminal carbyne ruthenium
compounds.10,11
The participation of allenylidene complexes in some recent
and outstanding catalytic processes involves electron-rich metal-
lic fragments:
plexes via Cꢀ-Cγ addition of nucleophiles. Thus, allenylidene
derivatives with the metal fragment [Cp*Ru(dippe)]+ (dippe )
1,2-(diisopropylphosphino)ethane) can be protonated, and the
corresponding alkenylcarbyne becomes reactive toward weak
aprotic nucleophiles such as simple ketones (via enol tautomer),
heterocycles, and activated arene compounds. An acidic alle-
nylidene activation is required, including the use of protic
nucleophiles, acidic enough to promote the direct Cꢀ-Cγ
addition to the allenylidene complexes.14
The aim of this work is to extend these results to a metal
fragment bearing two monodentate phosphine ligands (PEt3)
instead of the chelating diphosphine dippe. This would confirm
that this novel reactivity is not exclusive to chelating diphos-
phine systems, showing the effect of bulkier and more labile
auxiliary ligands on this novel allenylidene/alkenylcarbyne
reactivity.
Previous studies on the complex [Cp*RuCl(PEt3)2] led to the
establishment of the full sequence of species preceding the
allenylidene formation by activation of propargyl alcohol
derivatives.15 It was also reported that phosphine dissociation
takes place during the formation of dialkyl-substituted alle-
nylidene complexes, leading to zwitterionic alkynylphosphonio
derivatives.
In this paper, we report the synthesis and characterization of
a series of allenylidene and alkenylcarbyne complexes obtained
from the activation of propargyl alcohols by [Cp*RuCl(PEt3)2].
(a)Theallenylidene[(p-cymene)RuCl(dCdCdCPh2)(PCy3)]+
is the key precursor of a highly active catalyst for olefin
metathesis. Protonation at Cꢀ and the ulterior rearrangement
generate in situ an indenylidene metal catalyst, resulting from
the phenyl C-H bond addition to the CR-Cꢀ allenylidene
double bond.11
(b) The ruthenium-catalyzed propargylic substitution of
propargylic alcohols with a variety of nucleophiles12 has
emerged as a catalytic alternative to the Nicholas reaction.13
The process implies the intermolecular addition of nucleophiles
to the Cꢀ-Cγ double bond of an allenylidene intermediate. At
difference with the previous examples, the key step of the
catalytic cycle had no precedent in the stoichiometric alle-
nylidene reactivity (Scheme 1).
In recent publications, we have reported a first stoichiometric
approach to this process, an alternative to the classical reactivity
of electrophilic allenylidenes. It was shown how the relationship
between allenylidenes and their alkenylcarbyne conjugate acid
is involved in the formation of γ-substituted vinylidene com-
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1548 Organometallics, Vol. 28, No. 5, 2009
Pino-Chamorro et al.
Scheme 2. Allenylidene Synthesis
The use of a variety of substituted propargyl alcohols (1-(4-
methoxyphenyl)-2-propyn-1-ol, 1-phenyl-2-propyn-1-ol, 1-(4-
fluorophenyl)-2-propyn-1-ol, and 1,1-diphenyl-2-propyn-1-ol)
will allow us to tune the electronic properties of the allenylidene
ligand and observe the effect on their stability and reactivity.
As a result, neutral alkynyl, dicationic alkenylcarbyne,
monocationic γ-substituted vinylidene, and bicyclic carbene
complexes have been isolated and characterized. The cycload-
dition products obtained by double addition of 1,3-cyclohex-
anedione and resorcinol (benzene-1,3-diol) to both allenylidene
double bonds are reported. The X-ray structures of a secondary
allenylidene and an alkenylcarbyne complex are reported for
ruthenium complexes bearing monodentate phosphine ligands.
Figure 1. ORTEP view of the cation complex of [Cp*Ru-
(dCdCdCHPh)(PEt3)2][BF4] (4). Selected bond lengths (Å) and
angles (deg): Ru(1)-P(1) 2.338(2), Ru(1)-P(2) 2.329(3), Ru(1)-
C(11) 1.884(8), C(11)-C(12) 1.244(13), C(12)-C(13) 1.353(14);
P(1)-Ru(1)-P(2)93.39(9),Ru(1)-C(11)-C(12)175.2(7),C(11)-C(12)-C(13)
169.6(10), C(12)-C(13)-C(14) 125.2(10).
allenylidene ligand, showing a strong IR absorption around 1910
cm-1 for ν(CdCdC), the characteristic sequence of chemical
shifts for the C3 unit (δ(CR) > δ(Cꢀ) > δ(Cγ)) with the carbene
carbon atom around 295 ppm in the 13C{1H} NMR spectra, and
a singlet corresponding to the proton attached to Cγ for the
Results and Discussion
Synthesis of Allenylidene and Alkenylcarbyne Complexes.
Regardless of the equivalent ligand distribution around
ruthenium, the presence of two monodentate phosphine
ligands instead of the chelating diphosphine dippe marks a
difference in stability and reactivity of their derivatives,
besides the variations in electron-releasing capability and
cone angle imposed by the particular alkyl substituents.
Therefore, the allenylidene synthesis starting from the
fragment [Cp*RuCl(PEt3)2] (1) requires a more careful
treatment to avoid side reactions, which are not operative in
the case of compounds with the chelating dippe ligand.
Furthermore, the synthetic procedure to obtain allenylidene
complexes from [Cp*RuCl(PEt3)2] has been modified to
prepare them as [BF4]- salts, thus avoiding [BPh4]-, which
is unstable under acidic conditions.16
Most of the known allenylidene complexes have been
prepared from 1,1-diphenyl-2-propynol, which provides the
highest stability to the unsaturated ligand.1,2 Therefore, it reacts
smoothly with complex 1 in CH2Cl2 in the presence of an excess
of NaBF4, giving rise to the compound [Cp*Ru(dCdCdCPh2)-
(PEt3)2][BF4] (2) in almost quantitative yield as a dark red solid
(Scheme 2).
On the other hand, the synthesis of secondary allenylidene
complexes has always been challenging and often limited by
the partial dehydration of the 3-hydroxyvinylidene precursor.
This limitation can be overcome by passing the reaction mixture
through an acidic alumina column.15 This procedure has been
applied to the reactions with 1-(4-methoxyphenyl)-2-propyn-
1-ol, 1-phenyl-2-propyn-1-ol, and 1-(4-fluorophenyl)-2-propyn-
1-ol, obtaining the corresponding complexes [Cp*Ru(dCdCd
CHR)(PEt3)2][BF4] (R ) p-MeO-C6H4 (3), C6H5 (4), p-F-C6H4
(5)). Yields are good (79-85%) for 3 and 4, but considerably
lowered (27% for 5) when electron-releasing groups are
introduced (p-MeO-C6H4 ∼ C6H5 > p-F-C6H4). The spectro-
scopic features of complexes 2-5 confirm the presence of an
1
secondary allenylidenes 3-5 close to 9 ppm in the H NMR
spectra.
Recrystallization of complex 4 has provided suitable crystals
for X-ray diffraction analysis. Only three X-ray structures for
secondary allenylidene complexes have been reported so far,
namely, the C5H-bridged binuclear complex [CpRu(PPh3)2-
CdCdCHCt CRu(PPh3)2Cp][BPh4]17 and the mononuclear
complexes [RuCl(dCdCdCHPh)(dppe)2][PF6]18 and [Cp*Ru-
(dCdCdCHPh)(dippe)][BPh4].14a Figure 1 shows an ORTEP
view of the cation complex 4. Comments on the structure
features are provided later in the X-ray structure section.
The allenylidene complexes 2-5 are stable in methanol and
acetone solutions and are inert to stronger neutral nucleophiles
such as 2-methylfuran. At first sight, these complexes are very
stable, with an inert R-carbon protected by the combined steric
effect of Cp* and phosphine ligands and a decreased electro-
philic character at the γ-carbon due to the good electron-
releasing properties of the auxiliary ligands.
Alternatively, they are readily protonated by an excess of
tetrafluoroboric acid in CH2Cl2, yielding a series of alkenyl-
carbyne complexes [Cp*Ru(t C-CHdCRR′)(PEt3)2][BF4]2 (R
) R′ ) Ph (6); R ) H, R′ ) p-MeO-C6H4 (7), C6H5 (8), p-F-
C6H4 (9)) as dark red solids (Scheme 3). The yields are good
(81-88%) with respect to the starting allenylidene complexes.
A larger excess of HBF4 is necessary for the preparation of 9.
The IR spectra lack the characteristic allenylidene band,
1
confirming the complete conversion. The H NMR spectrum
shows a singlet at 6.85 ppm for the incoming proton at Cꢀ in
complex 6. For complexes 7-9, it appears as a doublet because
of the coupling with the adjacent hydrogen at Cγ. The coupling
(17) Xia, H. P.; Wu, W. F.; Ng, W. S.; Williams, I. D.; Jia, G.
Organometallics 1997, 16, 2940–2947.
(18) Colbert, M. C. B.; Lewis, J.; Long, N. J.; Raithby, P. R.; Younus,
M.; White, A. J. P.; Williams, D. J.; Payne, N. N.; Yellowlees, L.; Beljonne,
D.; Chawdhury, N.; Friend, R. H. Organometallics 1998, 17, 3034.
(16) Cooper, J. N.; Powell, R. E. J. Am. Chem. Soc. 1963, 85, 1590.

Allenylidene/Alkenylcarbyne Synthesis and ReactiVity
Organometallics, Vol. 28, No. 5, 2009 1549
Scheme 3. Synthesis of Alkenylcarbyne Complexes
the phosphine ethyl groups. Both orientations have already been
found in complexes such as [Cp*Ru(dCdCdCHPh)(dippe)]-
[BPh4]14a (toward the phosphine) and [CpRu(dCdCd
CMePh)(dippe)][BPh4]20 (toward the Cp ligand). Thus, the steric
requirements (Cp < Cp* < dippe < (PEt3)2) are responsible
for this structural feature. The PEt3 ligands also determine a
higher P(1)-Ru(1)-P(2) angle (93.39(9)°) compared to dippe
complexes (∼80°).
Theoretically, metal-allenylidene π-overlap is maximized
when the allenylidene atoms lie on the plane defined by Ru(1),
C(1), and the Cp* centroid (idealized mirror plane).21 Complex
4 deviates from this rule by 17.07° (dihedral angle between the
planes C(12)-C(13)-C(14) and C(11)-Ru(1)-Cp(centroid)).
The deviation is higher than in [Cp*Ru(dCdCdCHPh)-
(dippe)][BPh4] (3.51°) and shows that the Cp*/PEt3 ligand
combination imposes a more crowded environment around the
ruthenium center than in Cp*/dippe systems. The joint steric
effect of PEt3 and Cp* ligands distorts the theoretical electronic
preference for the allenylidene orientation, as similarly observed
for a π-alkyne complex of the same fragment.22
Scheme 4. Two-Step Synthesis of Substituted Vinylidenes
The analysis of how the molecular structure determines the
chemical reactivity continuously represents a challenge for
modern chemistry. Allenylidene complexes constitute a good
example of this correlation, which can be easily rationalized
on the basis of a simple resonance model:
{[Ru]+dCdCdCRR ′ T [Ru]-Ct C-C+RR ′ T
[Ru]-C+dCCdRR′}
constants of 15-16 Hz are consistent with a trans arrangement
around the Cꢀ-Cγ double bond. The carbyne carbon atom gives
rise to a triplet signal in the range 329-335 ppm, with a C-P
coupling constant of 13 Hz in the 13C{1H} NMR spectra. The
resonance corresponding to Cγ is found at lower field than that
of Cꢀ, as observed in other ruthenium vinylcarbyne complexes.9,14
Recrystallization of complexes 6-9 did not afford suitable
crystals for X-ray diffraction analysis. Thus, the counterion
[BF4]- has been replaced by [B(ArF)4]- (ArF ) 3,5-(CF3)2C6H3)
by treating complex 6 with a solution of NaB(ArF)4 in
fluorobenzene until complete dissolution of the complex and
precipitation of the NaBF4 salt. Slow diffusion of petroleum
ether into a fluorobenzene solution of 6′ (with [B(ArF)4] as
counterion) provided the adequate monocrystals. The X-ray
structure has been determined and confirms the presence of an
alkenylcarbyne ligand. A comparative discussion of the struc-
tural data is provided in the next section.
Ruthenium alkenylcarbyne species are still very scarce, and
the reactivity of electron-rich allenylidene complexes via
alkenylcarbyne intermediates remains relatively unknown com-
pared to that of electrophilic allenylidenes. The conjugated pair
allenylidene/alkenylcarbyne resembles the alkynyl/vinylidene
pair, which is involved in several catalytic transformations of
alkynes.19
The allenylidene bond lengths (Ru(1)-C(11), 1.884(8) Å;
C(11)-C(12), 1.244(13) Å, C(12)-C(13), 1.353(14) Å) show
a significant contribution of the alkynyl resonance form, as
inferred from the shorter CR-Cꢀ bond length compared to
Cꢀ-Cγ. The stabilization of the partial positive charge at Cγ is
determined by the degree of back-bonding from the metal center
and by the substituents at Cγ, thus explaining the low reactivity
of the electron-rich allenylidene toward nucleophiles and the
relatively higher reactivity of monosubstituted allenylidene
complexes.
The alkenylcarbyne 6′ also shows a three-legged piano-stool
geometry for the dication complex. The protonation at Cꢀ
modifies the bond angles along the carbon chain. Whereas the
angle Ru-CR-Cꢀ remains close to linearity (167.7(3)°), the
CR-Cꢀ-Cγ angle of 127.6(4)° involves a sp2 hybridation at Cꢀ.
The angles around Cγ also support a sp2 hybridation for this
atom.
The Ru-CR bond length of 1.765(4) Å is significantly shorter
than that of the related allenylidene 4 (1.884(8) Å). Other
ruthenium alkenylcarbyne complexes show slightly shorter
distances (1.69-1.73 Å),9 but the Ru-CR bond length of the
complex [Cp*Ru(t C-CHdCPh2)(dippe)][BArF ] is essentially
4 2
the same (1.766 Å).14b Nonconjugated carbyne ruthenium
complexes usually exhibit Ru-C distances around 1.66 Å.10
X-ray Structures. The allenylidene complex 4 exhibits a
three-legged piano-stool geometry around the metal, with the
allenylidene ligand almost linearly assembled to the ruthenium
center (Ru(1)-C(11)-C(12) 175.2(7)°, C(11)-C(12)-C(13)
169.6(10)°). The angle C(12)-C(13)-C(14) of 125.2(10)° is
consistent with a sp2 hybridation at Cγ.
The almost identical CR-Cꢀ (1.382(5) Å) and Cꢀ-Cγ
(1.380(5) Å) distances constitute the most interesting structural
feature of complex 6′. This characteristic is shared with the
related dippe alkenylcarbyne complex (1.388 and 1.384 Å),
whereas other alkenylcarbyne complexes show slightly different
It is noteworthy that the phenyl substituent of the allenylidene
ligand is oriented toward the Cp* ligand, pointing away from
(20) de los R´ıos, I.; Jime´nez-Tenorio, M.; Puerta, M. C.; Valerga, P. J.
Organomet. Chem. 1997, 549, 221.
(19) Fischmeister, C.; Bruneau, C.; Dixneuf, P. H. Nucleophilic additions
to alkynes and reactions via vinylidene intermediates. In Ruthenium in
Organic Synthesis; Murahashi, S.-I., Ed.; Wiley: New York, 2004; pp 189-
217.
(21) Schelling, B. E. R.; Hoffmann, R.; Lichtenberger, D. L. J. Am.
Chem. Soc. 1977, 101, 585.
(22) Bustelo, E.; Carbo, J. J.; Lledos, A.; Mereiter, K.; Puerta, M. C.;
Valerga, P. J. Am. Chem. Soc. 2003, 125, 3311.

1550 Organometallics, Vol. 28, No. 5, 2009
Pino-Chamorro et al.
values (i.e., CR-Cꢀ 1.396 > Cꢀ-Cγ 1.360 Å).9 The simplest
explanation takes into account the following resonance model:
Scheme 5. Direct Vinylidene Synthesis from Allenylidene
and Protic Nucleophiles
{[Ru]2+t CdCHdCRR ′ T [Ru]+dCdCH-C+RR′}
The observed structure is intermediate between the proposed
alkenylcarbyne and vinylidene resonance forms, in agreement
with the longer Ru-C bond length (compared to pure Rut C
bonds) and the almost identical CR-Cꢀ and Cꢀ-Cγ bond order.
Once more, the degree of back-bonding from the metal center
and the additional stability provided by the Cγ substituents seem
to be decisive in the stabilization of the partial positive charge
localized at this carbon atom, within a more electrophilic
dicationic complex.
Allenylidene Reactivity toward Anionic and Protic
Nucleophiles. Electron-rich disubstituted allenylidenes are usu-
ally very stable and completely inert to neutral nucleophiles.
Anionic species regioselectively react with allenylidene 2,
yielding γ-substituted neutral alkynyl complexes, whose ulterior
protonation leads to γ-substituted vinylidene species. Thus, when
a THF solution of complex 2 is treated with nitromethane and
tBuOK, the neutral alkynyl complex [Cp*Ru{Ct CC(CH2NO2)-
Ph2}(PEt3)2] (10) is obtained as an orange solid (Scheme 4).
The IR band at 2061 cm-1 corresponding to ν(Ct C) is the most
characteristic spectroscopic feature. The R-carbon appears at
120.3 ppm as a triplet in the 13C{1H} NMR spectrum. Proton-
ation of complex 10 by HBF4 in CH2Cl2 give rise to the cationic
vinylidene [Cp*Ru{dCdCHC(CH2NO2)Ph2}(PEt3)2][BF4] (11),
showing a characteristic carbene low-field resonance at 337.0
ppm in the 13C{1H} NMR spectrum.
The vinylidene complex 11 is formally the result of the
nitromethane addition to the Cꢀ-Cγ double bond of the starting
allenylidene 2. This two-step procedure represents the only
access to γ-substituted vinylidene complexes from allenylidene
intermediates.23 However, the catalytic propargylic substitution
of propargyl alcohols via allenylidene intermediates involves a
direct Nu-H addition under mild and neutral conditions, which
is not compatible with the stoichiometric processes leading from
complex 2 to 11.
Monosubstituted allenylidenes are more reactive species due
to the lesser stabilization at the γ-position. However, complexes
3-5 were inert toward neutral nucleophiles such as methanol
or 2-methylfuran. On the other hand, they react instantaneously
with acidic species such as 1,3-diketonic derivatives to yield
the corresponding γ-substituted vinylidene complexes in one
step. The allenylidene complex 3 reacts with acetylacetone and
malononitrile to give [Cp*Ru{dCdCHCH(L)(p-MeO-C6H4)}-
(PEt3)2][BF4] (L ) CH(CH3CO)2 (12), CH(CN)2 (13)) in good
yields (91-93%) (Scheme 5).
constant of 35 Hz, which is generally observed for these kinds
of vinylidene complexes containing a chiral center at Cγ, which
renders diasterotopic the two phosphorus atoms.14,15,24
The allenylidene complex 4 reacts in a similar way toward
acetylacetone, yielding the vinylidene complex [Cp*Ru{dCd
CHCH(Ph)CH(COCH3)2}(PEt3)2][BF4] (14). Reaction of 4 with
the cyclic 1,3-indanedione (benzocyclopentane-1,3-dione) also
gives rise to the γ-substituted vinylidene [Cp*Ru{dCdCH-
CH(Ph)(C9H5O2)}(PEt3)2][BF4] (15). Additionally, the alle-
nylidene complex 5, bearing an electron-attracting group, reacts
readily with acetylacetone in dichloromethane solution, yielding
thevinylidenecomplex[Cp*Ru{dCdCHCH)(p-F-C6H4)CH(CO-
CH3)2}(PEt3)2][BF4] (16). Complexes 14-16 have been char-
acterized by IR, NMR, and elemental analysis, showing
spectroscopic features that compare well to those reported for
12 and 13. A detailed signal assignment is found in the
Experimental Section.
In all cases the reaction proceeds smoothly at room temper-
ature with good yields (81-93%), regardless of the particular
1,3-diketonic compound and the substituent (MeO, H, F) on
the allenylidene ligand. The proposed mechanism consists of
an initial allenylidene protonation generating the alkenylcarbyne/
enolate pair, which rapidly leads to the final product. A first
nucleophilic attack of the enol taoutomer at Cγ, followed by
protonation at Cꢀ, is discarded since allenylidenes 3-5 do not
react with analogous aprotic nucleophiles such as 2-methylfuran.
The fast reaction between alkenylcarbyne and enolate species
explains the negligible effect of the donor/attractor substituent
at the phenyl p-position (MeO, H, F), which should be
significant only when the generation and stabilization of a partial
positive charge at Cγ is the key reaction step. On the other hand,
the lower acidity of a diketonic compound such as 2-acetylcy-
clohexanone and 3-methylpentane-2,4-dione seems to explain
the lack of reactivity of these compounds toward allenylidenes
3-5.
1H NMR spectra of 12 and 13 show a characteristic ABC
pattern for the protons at the ꢀ, γ, and δ positions in the range
4.3-4.8 ppm. The vinylidene R carbon appears at around 342
ppm as a triplet with C-P coupling constant of 15 Hz, in the
13C{1H} NMR spectrum, with the carbonyl carbon atoms at
201.7 and 201.9 ppm for compound 12 and the cyano carbon
atoms at 112.6 and 112.7 ppm for complex 13. The 31P{1H}
NMR spectra exhibit two doublet signals with a P-P coupling
(23) (a) Cadierno, V.; Gamasa, M. P.; Gimeno, J.; Pe´rez-Carreno, E.;
Garc´ıa-Granda, S. Organometallics 1999, 18, 2821. (b) Cadierno, V.;
Conejero, S.; Gamasa, M. P.; Gimeno, J.; Pe´rez-Carreno, E.; Garc´ıa-Granda,
S. Organometallics 2001, 20, 3175. (c) Cadierno, V.; Conejero, S.; Gamasa,
M. P.; Gimeno, J.; Falvello, L. R.; Llusar, R. M. Organometallics 2002,
21, 3716. (d) Cadierno, V.; Conejero, S.; Gamasa, M. P.; Gimeno, J. Dalton
Trans. 2003, 3060. (e) Nishibayashi, Y.; Imajima, H.; Onodera, G.; Uemura,
S. Organometallics 2005, 24, 4106. (f) Esteruelas, M. A.; Go´mez, A. V.;
Lo´pez, A. M.; Modrego, J.; On˜ate, E. Organometallics 1997, 16, 5826.
(24) (a) Le Lagadec, R.; Roma´n, E.; Toupet, L.; Mu¨ller, U.; Dixneuf,
P. H. Organometallics 1994, 13, 5030. (b) 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.

Allenylidene/Alkenylcarbyne Synthesis and ReactiVity
Organometallics, Vol. 28, No. 5, 2009 1551
Scheme 6. Cycloaddition of 1,3-Cyclohexanedione to Allenylidene
Scheme 7. Mechanistic Proposal for the Cycloaddition Reaction
The reaction of the allenylidene complexes 3-5 with 1,3-
lated products when acyclic ꢀ-diketones are employed and
cycloaddition products when starting from 1,3-cyclohexanedi-
one.26 Although allenylidene intermediates are proposed and
isolated for this catalytic reaction, the following steps in the
catalytic cycle (propargylic alkylation and ulterior intramolecular
cyclization) had no precedent in the allenylidene stoichiometric
reactivity. Now, the reported reactivity of electron-rich alle-
nylidene complexes illustrates how the catalytic process may
take place through γ-substituted vinylidene and subsequent
intramolecular OH addition. Attempts to release the organic
fragment (4,6,7,8-tetrahydrochromen-5-one) failed. The treat-
ment of the carbene 18 with a base gives rise to the neutral
bicyclic alkenyl complex [Cp*Ru(C9H8O2Ph)(PEt3)2] (20), as
a result of the selective deprotonation at the ꢀ-carbon position
(Scheme 6). The 13C{1H} NMR spectrum of 20 shows a triplet
signal at 178.4 ppm for the carbon atom directly attached to
ruthenium, whereas the second alkenyl carbon atom appears at
116.9 ppm.
cyclohexanedione apparently proceeds in a similar way to the
linear 1,3-dicarbonyl compounds. However, instead of the
expected vinylidene species, a series of bicyclic carbene
compounds have been isolated and identified as [Cp*Ru-
(C9H9O2R)(PEt3)2][BF4] (R ) p-MeO-C6H4 (17), C6H5 (18), p-F-
C6H4 (19)), in 90-94% yield (Scheme 6).
The 31P{1H} NMR signals are two doublets within the range
δ 31.0-31.8 ppm and a coupling constant of 35 Hz, similarly
to vinylidenes 12-16. At difference with them, the 13C{1H}
NMR spectra show the carbene signal at around δ 290 ppm,
whereas the vinylidene carbene atom appears at 341-343 ppm.
Oxacyclocarbene ruthenium complexes such as [CpRu(dp-
pe)(L)][PF6] and [(C9H7)Ru(L)(P)2][PF6] (L ) 2-oxacyclohexy-
lidene) exhibit triplet signals within the range δ 296-304 ppm,
respectively, for the carbene carbon atom.25 Quaternary carbons
for the carbonyl and alkenyl groups are observed at around δ
1
196, 165, and 117 ppm, respectively. The H NMR spectra of
Alkenylcarbyne Reactivity toward Aprotic Nucleophiles. In
agreement with the structural information obtained from the
X-ray analysis, the alkenylcarbyne reactivity is controlled by
the stabilization of the carbenium character at Cγ, which is
relatively enhanced compared to the corresponding allenylidene
precursor. In agreement with this, reactions from the isolated
alkenylcarbyne complexes do not require the use of protic
nucleophiles. At difference with allenylidene, alkenylcarbyne
reactions are very sensitive to the presence of electron donors
or withdrawing groups at the para position of the terminal
phenyl ring. Quantitative kinetic studies by NMR were not
possible due to the large difference in reaction rates for the
different substituents employed (R ) H ∼ F . OMe) and the
low thermal stability of these complexes of monodentate
phosphines.
2-Methylfuran, 1,3-dimethoxybenzene, and resorcinol (1,3-
benzenediol) have been employed as aprotic nucleophiles, all
of them bearing activated C-C double bonds (RO-CdC-).
In all cases, no reaction is observed with the corresponding
allenylidene complexes. Alkenylcarbynes 6 (R, R′ ) Ph, Ph)
and 7 (R, R′ ) H, p-MeOC6H5) were very stable against these
kinds of nucleophiles. Particularly, complex 7 showed very slow
reactions, giving mixtures of the expected complexes with
decomposition products during heating.
17-19 show a characteristic diasterotopic methylene group
adjacent to the carbene moiety and to the former alkynol chiral
center (Cγ). The geminal protons (2JHH ) 17-18 Hz) are also
coupled with the hydrogen attached at Cγ (3JHH ) 4-5 Hz).
The assignment is confirmed by two-dimensional NMR and
DEPT experiments.
The formation of a series of 4-aryl-5-oxo-hexahydrochromen-
2-ylidene ligands can be rationalized as the result of a double
addition of the 1,3-cyclohexanedione to the allenylidene carbon
chain, starting by protonation at Cꢀ and C-C bond formation
at Cγ to give an intermediate vinylidene ligand (as observed
for linear 1,3-diketonic compounds), followed by O-H addition
to the CR-Cꢀ double bond (Scheme 7). The vinylidene
intermediate has already been observed for the same reaction
with the [Cp*Ru(dippe)]+ system. In this case, a mixture of
both carbene and vinylidene complexes, which seemed to be
in equilibrium, was obtained.14d For the [Cp*Ru(PEt3)2]+
fragment, that equilibrium is completely shifted to the carbene
isomer, as the vinylidene intermediate is not observed.
The different behavior shown by linear and cyclic ꢀ-diketones
has also been observed for the catalytic reaction of propargylic
alcohols with 1,3-dicarbonyl compounds, which affords γ-alky-
(25) (a) Beddoes, R. L.; Grime, R. W.; Hussain, Z. I.; Whiteley, M. W.
J. Organomet. Chem. 1996, 526, 371. (b) Gamasa, M. P.; Gimeno, J.;
Mart´ın-Vaca, B. M.; Isea, R.; Vegas, A. J. Organomet. Chem. 2002, 651,
22.
(26) Nishibayashi, Y.; Yoshikawa, M.; Inada, Y.; Hidai, M.; Uemura,
S. J. Org. Chem. 2004, 69, 3408.

1552 Organometallics, Vol. 28, No. 5, 2009
Pino-Chamorro et al.
Scheme 8. Substituted Vinylidenes from Alkenylcarbyne and
Aprotic Nucleophiles
Scheme 9. Cycloaddition of Resorcinol to Alkenylcarbyne
Complexes
complexes) in the 13C{1H} NMR spectra. The methylene group,
next to the carbene carbon atom and to the chiral center at C4,
is diastereotopic and exhibits two signals (1H NMR) correlated
to the carbon atom appearing at around δ 60 ppm (13C{1H}
NMR) by HSQC two-dimensional spectra.
A related ruthenium-catalyzed cycloaddition of propargylic
alcohols with 2-naphthols and phenols via allenylidene inter-
mediates has been reported by Nishibayashi et al.,12d where the
detailed reaction mechanism was not completely elucidated. This
catalytic process yields directly the released organic fragment
(pyrans and benzopyrans) without detection of any intermediate
except the allenylidene. Our stoichiometric research on mono-
nuclear ruthenium complexes adds new insights into this
catalytic process by the isolation of the key species and the
description of this novel stoichiometric allenylidene reactivity.
However, the alkenylcarbynes 8 and 9 slowly change from
dark red to light orange when treated with an excess of
2-methylfuran and stirred for 4 h. After workup, γ-substituted
vinylidene complexes [Cp*Ru{dCdCHCH(R)(CH3-C4H2O)}-
(PEt3)2][BF4] (R ) C6H5 (21), p-F-C6H4 (22)) are isolated as
brown solids (Scheme 8). Similarly, complex 9 also reacts with
an excess of 1,2-dimethoxybenzene, yielding the vinylidene
complex [Cp*Ru{dCdCHCH(p-C6H4-F)(C6H3-(OCH3)2)}-
(PEt3)2][BF4] (23) as a result of the aromatic electrophilic
substitution of this activated electron-rich arene (Scheme 8).
This reaction takes place with the most electrophilic alkenyl-
carbyne complex 9, and in this case complexes 7 and 8 gave
similar results (too slow reactions, decomposition when heating).
NMR spectra for complexes 21-23 are quite similar to the
other substituted vinylidene compounds described before
(12-16), showing characteristic 1H and 31P{1H} NMR spectra
and particulary 13C{1H} NMR signals as low-field triplets at δ
344 ppm. The 1,3-dimethoxyphenyl group is regiospecifically
attached to the vinylidene γ-carbon through its 4-position, which
is the most activated to aromatic electrophilic substitutions with
a lesser steric hindrance, as confirmed by 1H and 13C{1H} NMR.
The key step of allenylidene reactions seems to be the initial
allenylidene protonation, and thus it depends on the relative
acidity of the different nucleophiles. In contrast, alkenylcarbyne
reactions mainly depend on the stabilization of the partial
positive charge at Cγ toward activated nucleophilic species,
showing a marked dependence on the electronic properties of
the aryl substituents.
Resorcinol is another arene compound activated toward
electrophilic aromatic substitution. Similarly to 1,3-dimethoxy-
benzene, resorcinol does not react directly with allenylidenes,
but alkenylcarbyne complexes 8 and 9 undergo a double addition
(C-H and O-H), giving rise to a bicyclic carbene derivative
with a neoflaVonoid skeleton, which consists of a chromane ring
bearing a second aromatic ring in position 4 and the carbene at
position 2 (Scheme 9).
The reaction resembles that previously described for alle-
nylidene and 1,3-cyclohexanedione, giving in both cases
analogous cycloaddition products. The resulting complexes
[Cp*Ru(C9H7O2R)(PEt3)2][BF4] (R ) C6H5 (24), p-F-C6H4 (25))
contain a 7-hydroxy-4-phenylchroman-2-ylidene ligand, which
has already been structurally described (DRX) for the analogous
[Cp*Ru(dippe)]+ fragment.14d
Conclusions
The catalytic propargylic substitution of propargyl alcohol
derivatives with nucleophiles is a reaction of great interest that
has definitively showed the participation of allenylidene com-
plexes as key intermediates in the catalytic processes. During
the last years, our group has developed a new stoichiometric
reactivity of allenylidene via alkenylcarbyne species, which has
illustrated for the first time the key step of this catalytic process,
namely, the direct formation of γ-substituted vinylidene com-
pounds. Although there are obvious differences between the two
ruthenium systems, we are reporting the unique and closest
stoichiometric approach to this novel allenylidene reactivity
mode. In this paper we have extended our previous results to
ruthenium complexes bearing monodentate phosphine ligands
instead of the former chelating diphosphine dippe. In spite of
the lowest stability of these derivatives (the loss of one
phosphine ligand, which can lead to decomposition products,
is a known issue for this kind of complex), we have been able
to prepare a series of allenylidene and alkenylcarbyne complexes
and to study their reactivity. One secondary allenylidene and
one dicationic alkenylcarbyne complex have been characterized
by DRX.
Allenylidenes do not react with nucleophiles unless they
contain acidic protons (i.e., diketonic compounds). In this case,
the reaction proceeds directly to give the corresponding vi-
nylidene compounds and the reaction rate does not show an
effect with regard to the presence of different substituents on
the allenylidene aryl group. On the other hand, the isolated
alkenylcarbyne complexes do react with aprotic nucleophiles
(i.e., 2-methylfuran), yielding similar vinylidene species. The
substituents’ effect is very marked on the reaction rate, showing
their participation in the stabilization of the partial positive
charge at the alkenylcarbyne γ-carbon atom. Cycloaddition
products have been obtained by double addition of resorcinol
and 1,3-cyclohexanedione to the alkenylcarbyne and allenylidene
complexes, respectively.
The most characteristic spectroscopic feature of complexes
24 and 25 is the resonance of the carbenic carbon atom, which
appears at δ 290.3 and 291.4 ppm (287-289 ppm for dippe

Allenylidene/Alkenylcarbyne Synthesis and ReactiVity
Organometallics, Vol. 28, No. 5, 2009 1553
9.23 (s, 1 H, RudCdCdCH). IR (Nujol): ν(CdCdC) 1915 cm-1
31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 32.84 (s).
.
Our current efforts are focused on finding suitable mono-
nuclear ruthenium systems able to promote reversible alkyne/
vinylidene isomerization, which seems to be the key step toward
a catalytic application of this novel reactivity.
5: Anal. Calcd for C31H50BF5P2Ru: C, 53.8; H, 7.29. Found: C,
54.0; H, 7.30. 1H NMR (400 MHz, CDCl3, 298 K): δ 1.00 (m, 18
H, PCH2CH3), 1.90 (s, 15 H, C5(CH3)5), 1.72 and 1.96 (m, 12 H,
3
3
PCH2CH3), 7.09 (vt, 2 H, JHH ) JHF ) 8.6 Hz, m-C6H4F), 7.80
3
4
Experimental Section
(dd, 2 H, JHH ) 8.6, JHF ) 5.5 Hz, o-C6H4F), 9.19 (s, 1 H,
RudCdCdCH). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ
32.7 (s). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 8.56 (s,
PCH2CH3), 11.03 (s, C5(CH3)5), 21.07 (m, PCH2CH3), 102.8 (s,
All synthetic operations were performed under a dry dinitrogen
or argon atmosphere by following conventional Schlenk techniques.
Tetrahydrofuran, diethyl ether, and petroleum ether (boiling point
range 40-60 °C) were obtained oxygen- and water-free from an
Innovative Technology Inc. solvent purification apparatus. Dichlo-
romethane and nitromethane were of anhydrous quality and used
as received. All solvents were deoxygenated immediately before
use. Propargylic alcohols were prepared by the reaction of the
corresponding p-substituted benzaldehyde with ethynylmagnesium
bromide, except 1-phenyl-2-propyn-1-ol, which is commercially
available.
IR spectra were recorded in Nujol mulls on a Perkin-Elmer FTIR
Spectrum 1000 spectrophotometer. NMR spectra were taken on a
Varian Inova 600, Varian Inova 400, or Varian Gemini 300
equipment. Chemical shifts are given in parts per million from
SiMe4 (1H and 13C{1H}) or 85% H3PO4 (31P{1H}). 1H and 13C{1H}
NMR signal assignments were confirmed by 1H-gCOSY, 135-
DEPT, and gHSQC(1H-13C) experiments. Microanalysis was
performed on a LECO CHNS-932 elemental analyzer at the Servicio
Central de Ciencia y Tecnolog´ıa, Universidad de Ca´diz.
3
4
C5(CH3)5), 117.4 (d, JCF ) 22.7 Hz, m-C6H4), 131.5 (d, JCF
)
5
8.5 Hz, o-C6H4), 138.1 (s, RudCdCdCH), 139.7 (d, JCF ) 2.8
1
Hz, ipso-C6H4), 164.3 (d, JCF ) 256.8 Hz, p-C6H4), 220.2 (s, Ru
dCdC), 299.5 (t, 2JCP ) 18.9 Hz, RudC). IR (Nujol): ν(CdCdC)
1907 cm-1
.
Preparation of [Cp*Ru{t CCHdCRR′}(PEt3)2][BF4]2 (R )
Ph, R′ ) Ph (6); R ) H, R′ ) p-MeO-C6H4 (7), C6H5 (8),
p-F-C6H4 (9)). An excess of HBF4 (100 µL, 54 wt % solution in
Et2O, 0.40 mmol) was added to a CH2Cl2 solution of the
corresponding allenylidene 2-5 (0.25 mmol), causing a fast color
change to dark red. After stirring the mixture for 15 min, the solvent
was evaporated under vacuum and the residue washed with 3 ×
10 mL of Et2O in order to remove the excess acid. The resulting
dark red solid was then dried under reduced pressure. Yields: 184
mg of 6 (88%), 170 mg of 7 (86%), 167 mg of 8 (88%), 158 mg
of 9 (81%).
6: Anal. Calcd for C37H56B2F8P2Ru: C, 53.1; H, 6.74. Found: C,
53.1; H, 6.77. 1H NMR (400 MHz, CD3NO2, 298 K): δ 1.17-1.25
(m, 18 H, PCH2CH3), 2.05-2.11 (m, 12 H, PCH2CH3), 2.12 (s, 15
H, C5(CH3)5), 6.85 (s, 1 H, Rut C-CH), 7.49 and 7.66 (d, 4 H,
Preparation of [Cp*Ru{dCdCdCRR′}(PEt3)2][BF4] (R )
Ph, R′ ) Ph (2); R ) H, R′ ) p-MeO-C6H4 (3), C6H5 (4),
p-F-C6H4 (5)). A 300 mg (0.60 mmol) amount of compound
[Cp*RuCl(PEt3)2] (1) was dissolved in 10 mL of CH2Cl2. An excess
of NaBF4 (150 mg, 1.36 mmol) and 0.70 mmol of the corresponding
propargyl alcohol were added immediately. The mixture was stirred
until a clear color change from orange to dark brown was observed
(3-5 h). Filtration through Celite and removal of the solvent under
vacuum yielded compound 2 as a dark brown solid in quantitative
yield. In the case of compounds 3-5, the solution had to be passed
through an acidic alumina column (activity grade I, height of
column 5 cm) and eluted with CH2Cl2. The dark brown band
collected was then taken to dryness, giving a dark brown solid,
which was washed with 2 × 10 mL of Et2O and dried under
vacuum. Yields: 405 mg of 2 (90%), 359 mg of 3 (85%), 319 mg
of 4 (79%), 112 mg of 5 (27%). Full spectroscopic characterization
for complexes 2 and 4 as BPh4 salts was already reported.14a
2: Anal. Calcd for C37H55BF4P2Ru: C, 59.3; H, 7.39. Found: C,
3
3JHH ) 7.0 Hz, o-C6H5), 7.55 and 7.80 (t, 4 H, JHH ) 7.0 Hz,
3
m-C6H5), 7.92 (t, 2 H, JHH ) 7.0 Hz, p-C6H5). 31P{1H} NMR
(161.89 MHz, CD3NO2, 298 K): δ 30.9 (s). 13C{1H} NMR (75.4
MHz, CD3NO2, 298 K): δ 10.10 (s, PCH2CH3), 11.58 (s, C5(CH3)5),
22.26-23.09 (m, PCH2CH3), 111.5 (s, C5(CH3)5), 130.8, 131.0,
132.6, 132.8, 135.4, 137.0, and 139.7 (s, C6H5), 130.9 (s,
2
Rut C-CH), 179.7 (s, CHdCPh2), 329.0 (t, JCP ) 12.5 Hz,
RudC). IR (Nujol): ν(Ph) 1594 cm-1
.
7: Anal. Calcd for C32H54B2F8OP2Ru: C, 48.6; H, 6.88. Found:
C, 48.5; H, 6.87. 1H NMR (400 MHz, CD2Cl2, 298 K): δ 0.90-1.29
4
(m, 18 H, PCH2CH3), 1.99 (t, 15 H, JHP ) 1.4 Hz, C5(CH3)5),
2.05-2.22 (m, 12 H, PCH2CH3), 3.95 (s, 3 H, CH3O-C6H4), 6.94
3
3
(d, 2 H, JHH ) 9.0 Hz, m-C6H4), 7.05 (d, 1 H, JHH ) 15.0 Hz,
3
Rut CCHdCH), 8.02 (d, 2 H, JHH ) 9.0 Hz, o-C6H4), 8.38 (d, 1
H, 3JHH ) 15.0 Hz, Rut CCHdCH). 31P{1H} NMR (161.89 MHz,
CD2Cl2, 298 K): δ 29.6 (s). 13C{1H} NMR (75.4 MHz, CD2Cl2,
298 K): δ 9.70 (s, PCH2CH3), 11.19 (s, C5(CH3)5), 21.40-22.20
(m, PCH2CH3), 56.96 (s, C6H4(OCH3)), 109.4 (s, C5(CH3)5), 116.6,
126.2, 126.6, and 161.2 (s, C6H4), 166.7 and 169.9 (s,
1
59.5; H, 7.44. H NMR (400 MHz, CDCl3, 298 K): δ 0.90-1.05
(m, 18 H, PCH2CH3), 1.80 (s, 15 H, C5(CH3)5), 1.60-1.92 (m, 12
H, PCH2CH3), 7.37 (t, 4 H, 3JHH ) 7.0 Hz, m-C6H5), 7.67 (m, 6 H,
o- and p-C6H5). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ
2
33.7 (s). IR (Nujol): ν(CdCdC) 1907 cm-1
.
Rut CCHdCH), 335.4 (t, JCP ) 13.0 Hz, RudC). IR (Nujol):
ν(Ph) 1601 cm-1
.
3: Anal. Calcd for C32H54BF4OP2Ru: C, 54.6; H, 7.59. Found:
C, 54.7; H, 7.56. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.96-1.03
8: Anal. Calcd for C31H52B2F8P2Ru: C, 48.9; H, 6.88. Found: C,
1
48.9; H, 6.89. H NMR (400 MHz, CD3NO2, 298 K): δ 1.34 (m,
(m, 18 H, PCH2CH3), 1.88 (s, 15 H, C5(CH3)5), 1.66-1.99 (m, 12
4
3
18 H, PCH2CH3), 2.13 (t, 15 H, JHP ) 1.3 Hz, C5(CH3)5), 2.32
H, PCH2CH3), 3.87 (s, 3 H, CH3O-C6H4), 6.93 (d, 2 H, JHH
)
3
3
(m, 12 H, PCH2CH3), 7.06 (d, 1 H, JHaHb ) 16.0 Hz,
9.0 Hz, m-C6H4), 7.75 (d, 2 H, JHH ) 9.0 Hz, o-C6H4), 8.95 (s, 1
H, RudCdCdCH). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K):
δ 32.8 (s). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 8.44 (s,
PCH2CH3), 10.93 (s, C5(CH3)5), 20.82-21.21 (m, PCH2CH3), 55.76
(s, CH3O-C6H4), 101.9 (s, C5(CH3)5), 115.7, 131.9, 137.1, and
162.9 (s, C6H4), 139.9 (s, RudCdCdCH), 209.0 (s, RudCdC),
3
Rut CCHdCH), 7.59 (t, 2 H, JHH ) 7.0 Hz, m-C6H5), 7.83 (t, 1
H, 3JHH ) 7.0 Hz, p-C6H5), 7.88 (d, 2 H, 3JHH ) 7.0 Hz, o-C6H5),
3
8.44 (d, 1 H, JHaHb ) 16.0 Hz, Rut CCHdCH). 31P{1H} NMR
(161.89 MHz, CD3NO2, 298 K): δ 31.6 (s). 13C{1H} NMR (75.4
MHz, CD3NO2, 298 K): δ 9.05 (s, PCH2CH3), 10.03 (s, C5(CH3)5),
21.35 - 22.10 (m, PCH2CH3), 110.6 (s, C5(CH3)5), 129.0, 130.2,
131.7, and 133.0 (s, C6H5), 137.7 (s, Rut CCH), 166.0 (s,
2
293.7 (t, JCP ) 19.0 Hz, RudC). IR (Nujol): ν(CdCdC) 1910
cm-1
.
2
Rut CCHdCH), 331.7 (t, JCP ) 13.0 Hz, RudC). IR (Nujol):
4: Anal. Calcd for C31H51BF4P2Ru: C, 55.3; H, 7.63. Found: C,
ν(Ph) 1632 cm-1
.
1
55.3; H, 7.65. H NMR (400 MHz, CDCl3, 298 K): δ 0.94-1.02
(m, 18 H, PCH2CH3), 1.88 (s, 15 H, C5(CH3)5), 1.70 and 1.95 (m,
12 H, PCH2CH3), 7.37 (d, 2 H, 3JHH ) 7.7 Hz, m-C6H5), 7.64 (t, 2
H, 3JHH ) 7.7 Hz, o-C6H5), 7.77 (d, 1 H, 3JHH ) 7.7 Hz, p-C6H5),
9: Anal. Calcd for C31H51B2F9P2Ru: C, 47.8; H, 6.60. Found: C,
47.5; H, 6.59. 1H NMR (400 MHz, CD3NO2, 298 K): δ 1.22-1.41
4
(m, 18 H, PCH2CH3), 2.12 (t, 15 H, JHP ) 1.4 Hz, C5(CH3)5),

1554 Organometallics, Vol. 28, No. 5, 2009
Pino-Chamorro et al.
2.28 and 2.36 (m, 12 H, PCH2CH3), 7.01 (d, 1 H, 3JHH ) 16.0 Hz,
12: Anal. Calcd for C37H61BF4O3P2Ru: C, 55.3; H, 7.65. Found:
C, 55.3; H, 7.65. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.99-1.12
(m, 18 H, PCH2CH3), 1.69 (s, 15 H, C5(CH3)5), 1.58-1.93 (m, 12
H, PCH2CH3), 1.83 and 2.33 (both s, 3 H each, CH(COCH3)2),
3.76 (s, 3 H, CH3O-C6H4), 4.37 (dd, 1 H, 3JHaHb ) 9.6 Hz, 3JHbHc
) 10.7 Hz, CHaCHb(Ar)CHc), 4.42 (d, 1 H, 3JHbHc ) 10.7 Hz, CHc),
3
3
Rut CCHdCH), 7.31 (vt, 2 H, JHH ) JHF ) 8.8 Hz, m-C6H4F),
3
4
7.99 (dd, 2 H, JHH ) 8.8, JHF ) 5.4 Hz, o-C6H4F), 8.42 (d, 1 H,
3JHH ) 16.0 Hz, Rut CCHdCH). 31P{1H} NMR (161.89 MHz,
CD3NO2, 298 K): δ 31.6 (s). 13C{1H} NMR (75.4 MHz, CD3NO2,
298 K): δ 10.07 (s, PCH2CH3), 11.32 (s, C5(CH3)5), 22.72 (m,
PCH2CH3), 111.7 (s, C5(CH3)5), 118.7 (d, 3JCF ) 22.0 Hz, m-C6H4),
4.62 (d, 1 H, 3JHaHb ) 9.6 Hz, RudCdCHa), 6.80 (d, 2 H, 3JHH
)
5
3
130.7 (d, JCF ) 2.5 Hz, ipso-C6H4), 131.1 (s, Rut CCH), 135.9
9.0 Hz, m-C6H4), 7.18 (d, 2 H, JHH ) 9.0 Hz, o-C6H4). 31P{1H}
4
2
(d, JCF ) 10.5 Hz, o-C6H4), 165.5 (s, Rut CCHdCH), 169.6 (d,
NMR (161.89 MHz, CDCl3, 298 K): δ 31.7 and 32.1 (d, JPP’
)
2
1JCF ) 260.1 Hz, p-C6H4), 332.6 (t, JCP ) 12.7 Hz, RudC). IR
34.1 Hz). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 8.55 and
8.81 (d, 2JCP ) 3.8 Hz, PCH2CH3), 10.16 (s, C5(CH3)5), 20.46 and
20.77 (m, PCH2CH3), 30.99 and 31.91 (s, CH(COCH3)2), 38.24 (s,
CH(COCH3)2), 54.84 (s, CH3O-C6H4), 73.26 (s, CH(Ar)), 102.1
(s, C5(CH3)5), 110.7 (s, RudCdCH), 113.5, 128.2, 134.1 and 158.0
(s, C6H4), 201.7 and 201.9 (s, CO), 342.6 (t, 2JCP ) 15.1 Hz, RudC).
(Nujol): ν(Ph) 1623 cm-1
.
Preparation of [Cp*Ru{Ct CC(CH2NO2)Ph2}(PEt3)2] (10). A
150 mg (0.20 mmol) amount of the allenylidene complex 2 was
t
dissolved in 5 mL of THF, and then a suspension of BuOK (114
mg, 1 mmol) and nitromethane (61 µL, 1 mmol) in 5 mL of THF
was added. The mixture was stirred for 30 min, the solvent removed
in Vacuo, and the residue extracted with 2 × 10 mL of petroleum
ether. The resulting solution was filtered through Celite, and a
yellow solid was obtained after solvent removal under vacuum.
Yield: 129 mg (89%).
IR (Nujol): ν(CO) 1713, ν(CdC) 1650 cm-1
.
13: Anal. Calcd for C35H55BF4N2OP2Ru: C, 54.6; H, 7.20. Found:
C, 54.6; H, 7.22. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.99-1.20
(m, 18 H, PCH2CH3), 1.76 (s, 15 H, C5(CH3)5), 1.58-2.00 (m, 12
H, PCH2CH3), 3.84 (s, 3 H, CH3O-C6H4), 4.31 (dd, 1 H, 3JHaHb
)
3
3
10: Anal. Calcd for C38H57NO2P2Ru: C, 63.1; H, 7.95. Found:
C, 63.3; H, 7.97. 1H NMR (400 MHz, C6D6, 298 K): δ 0.61-0.68
(m, 18 H, PCH2CH3), 1.14-1.21 (m, 12 H, PCH2CH3), 1.40 (t, 15
H, 4JHP ) 1.2 Hz, C5(CH3)5), 4.68 (s, 2 H, CH2NO2), 6.77 (t, 2 H,
7.6 Hz, JHbHc ) 10.4 Hz, CHaCHb(Ar)CHc), 4.20 (d, 1 H, JHbHc
3
) 10.4 Hz, CHc), 4.77 (d, 1 H, JHaHb ) 7.6 Hz, RudCdCHa),
6.90 (d, 2 H, 3JHH ) 8.5 Hz, m-C6H4), 7.32 (d, 2 H, 3JHH ) 8.5 Hz,
o-C6H4). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 31.7 and
3
2
3JHH ) 8.0 Hz, p-C6H5), 6.88 (t, 4 H, JHH ) 8.0 Hz, m-C6H5),
31.9 (d, JPP’ ) 34.0 Hz). 13C{1H} NMR (75.4 MHz, CDCl3, 298
7.27 (d, 4 H, 3JHH ) 8.0 Hz, o-C6H5). 31P{1H} NMR (161.89 MHz,
C6D6, 298 K): δ 33.0 (s). 13C{1H} NMR (75.4 MHz, C6D6, 298
K): δ 9.08 (s, PCH2CH3), 11.32 (s, C5(CH3)5), 21.75-22.04 (m,
PCH2CH3), 52.00 (s, CPh2), 84.89 (s, CH2NO2), 91.47 (s, C5(CH3)5),
103.7 (s, Ru-Ct C), 120.3 (t, 2JCP ) 24.3 Hz, Ru-C), 126.2, 127.7,
128.6, and 146.2 (s, C6H5). IR (Nujol): ν(Ct C) 2061, ν(Ph) 1632
K): δ 8.55 and 8.99 (d, JCP ) 4.0 Hz, PCH2CH3), 10.69 (s,
2
C5(CH3)5), 20.81-21.31 (m, PCH2CH3), 31.42 (s, CH(CN)2), 39.73
(s, CH(Ar)), 55.28 (s, CH3O-C6H4), 103.2 (s, C5(CH3)5), 108.4
(s, RudCdCH), 112.6 and 112.7 (s, CH(Ct N)2), 114.3, 128.7,
2
130.8, and 159.6 (s, C6H4), 339.8 (t, JCP ) 14.8 Hz, RudC). IR
(Nujol): ν(Ct N) 2198, ν(CdC) 1633 cm-1
.
cm-1, ν(NO2) 1372 and 1551 cm-1
.
14: Anal. Calcd for C36H59BF4O2P2Ru: C, 55.9; H, 7.69. Found:
C, 55.9; H, 7.69. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.97-1.14
(m, 18 H, PCH2CH3), 1.69 (s, 15 H, C5(CH3)5), 1.60-1.93 (m, 12
H, PCH2CH3), 1.83 and 2.35 (both s, 3 H each, CH(COCH3)2),
4.37 (dd, 1 H, 3JHaHb ) 9.4 Hz, 3JHbHc ) 10.5 Hz, CHaCHb(Ph)CHc),
Preparation of [Cp*Ru{dCdCHC(CH2NO2)Ph2}(PEt3)2][BF4]
(11). A 129 mg (0.18 mmol) amount of complex 10 was dissolved
in 5 mL of Et2O. The solution was cooled in an ethanol/liquid N2
bath and treated with an excess of HBF4 (100 µL, 54% solution of
HBF4 · Et2O, 0.40 mmol). Once removed from the bath, the red
suspension was allowed to warm to room temperature with stirring.
After the solvent was removed under vacuum, the residue was
extracted with 10 mL of CH2Cl2 and filtered through Celite. A
brown solid was obtained by elimination of the solvent under
vacuum and washing with 2 × 5 mL of Et2O. Yield: 118 mg (81%).
3
3
4.45 (d, 1 H, JHbHc ) 10.5 Hz, CHc), 4.63 (dt, 1 H, JHaHb ) 9.4
Hz, JHP ) 2.0 Hz, RudCdCHa), 7.37 (t, 2 H, JHH ) 7.3 Hz,
4
3
3
3
m-C6H5), 7.66 (t, 1 H, JHH ) 7.3 Hz, p-C6H5), 7.77 (d, 2 H, JHH
) 7.3 Hz, o-C6H5). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K):
δ 31.7 and 32.1 (d, JPP′ ) 35.0 Hz). 13C{1H} NMR (75.4 MHz,
2
2
CDCl3, 298 K): δ 9.00 and 9.32 (d, JCP ) 4.3 Hz, PCH2CH3),
10.61 (s, C5(CH3)5), 21.02 (m, PCH2CH3), 31.85 and 32.40 (s,
CH(COCH3)2), 39.42 (s, CH(COCH3)2), 73.00 (s, CHPh), 102.5
(s, C5(CH3)5), 111.0 (s, RudCdCH), 127.1, 127.8, 128.6, and 142.5
(s, C6H5), 202.4 and 202.6 (s, CO), 343.2 (t, 2JCP ) 15.4 Hz, RudC).
11: Anal. Calcd for C38H58BF4NO2P2Ru: C, 56.3; H, 7.21. Found:
C, 56.3; H, 7.24. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.90-1.00
(m, 18 H, PCH2CH3), 1.50-1.69 (m, 12 H, PCH2CH3), 1.76 (s, 15
H, C5(CH3)5), 4.44 (t, 1 H, 4JHP ) 2.2 Hz, RudCdCH), 5.14 (s, 2
H, CH2NO2), 7.19 and 7.25 (m, 10 H, C6H5). 31P{1H} NMR (161.89
MHz, CDCl3, 298 K): δ 27.3 (s). 13C{1H} NMR (75.4 MHz, CDCl3,
298 K): δ 9.24 (s, PCH2CH3), 10.90 (s, C5(CH3)5), 20.77-21.16
(m, PCH2CH3), 50.28 (s, CPh2), 85.20 (s, CH2NO2), 102.9 (s,
C5(CH3)5), 112.2 (s, RudCdCH), 127.4, 127.5, 128.4, and 143.2
IR (Nujol): ν(CO) 1695, ν(CdC) 1644 cm-1
.
15: Anal. Calcd for C40H57BF4O2P2Ru: C, 58.6; H, 7.01. Found:
C, 58.5; H, 7.02. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.89-1.15
(m, 18 H, PCH2CH3), 1.70 (s, 15 H, C5(CH3)5), 1.60-1.95 (m, 12
3
H, PCH2CH3), 3.26 (d, 1 H, JHbHc ) 11.0 Hz, CHaCHb(Ph)CHc),
2
3
3
(s, C6H5), 337.0 (t, JCP ) 14.5 Hz, RudC). IR (Nujol): ν(CdC)
4.49 (dd, 1 H, JHaHb ) 3.0 Hz, JHbHc ) 11.0 Hz, CHaCHbPh),
1643 cm-1, ν(Ph) 1633 cm-1, ν(NO2) 1375 and 1555 cm-1
.
4.95 (dt, 1 H, 3JHaHb ) 3.0 Hz, 4JHP ) 1.5 Hz, RudCdCHa), 7.10
and 7.14 (m, 5 H, C6H5), 7.78 and 7.84 (m, 4 H, C6H4). 31P{1H}
Preparation of [Cp*Ru{dCdCHCH(L)R}(PEt3)2][BF4] (R
) p-MeO-C6H4, L ) CH(CH3CO)2 (12), CH(CN)2 (13); R )
Ph, L ) CH(CH3CO)2 (14), C9H5O2 (15); R ) p-F-C6H4, L )
CH(CH3CO)2 (16)). A solution of the allenylidene complex 3-5
(0.25 mmol) in 5 mL of CH2Cl2 was treated with an excess (0.5
mmol) of the corresponding 1,3-diketonic derivative (acetylacetone,
malononitrile, 1,3-indanedione) and stirred at room temperature for
2 h, showing a gradual color change from dark to light brown.
Then, the solution was concentrated to less than 1 mL at reduced
pressure. Addition of 10 mL of a 1:1 mixture of Et2O and petroleum
ether caused the precipitation of a brown solid, which was washed
with petroleum ether and dried under vacuum. Yield: 187 mg of
12 (93%), 175 mg of 13 (91%), 178 mg of 14 (92%), 184 mg of
15 (90%), 161 mg of 16 (81%).
2
NMR (161.89 MHz, CDCl3, 298 K): δ 31.9 and 32.3 (d, JPP′
)
34.0 Hz). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 9.29 and
9.54 (d, 2JCP ) 3.8 Hz, PCH2CH3), 11.11 (s, C5(CH3)5), 21.11 and
21.66 (m, PCH2CH3), 37.95 (s, CH(CO)2), 59.75 (s, CHPh), 103.2
(s, C5(CH3)5), 109.5 (s, RudCdCH), 123.3, 123.4, 136.5, 142.7,
and 142.8 (s, C6H4), 127.8, 128.1, 128.9, and 141.2 (s, C6H5), 198.8
2
and 199.7 (s, CO), 341.0 (t, JCP ) 14.5 Hz, RudC). IR (Nujol):
ν(CO) 1704, ν(CdC) 1651 cm-1
.
16: Anal. Calcd for C36H58BF5O2P2Ru: C, 54.6; H, 7.38. Found:
C, 54.5; H, 7.35. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.97-1.15
(m, 18 H, PCH2CH3), 1.68 (s, 15 H, C5(CH3)5), 1.70-1.96 (m, 12
H, PCH2CH3), 1.85 and 2.37 (both s, 3 H each, CH(COCH3)2),
3
3
4.40 (vt, 1 H, JHaHb ) JHbHc ) 10.3 Hz, CHaCHb(Ar)CHc), 4.56

Allenylidene/Alkenylcarbyne Synthesis and ReactiVity
Organometallics, Vol. 28, No. 5, 2009 1555
3
3
4
6
(d, 1 H, JHaHb ) 10.3 Hz, CHc), 4.73 (dt, 1 H, JHH ) 10.3, JHP
CH2 ), 2.81 (m, 2 H, CH3aH3b + CH8aH8b), 2.99 (dt, 2JHaHb ) 17.9
) 1.5 Hz, RudCdCHa), 6.96 (vt, 2 H, JHH ) JHF ) 9.0 Hz,
m-C6H4F), 7.28 (dd, 2 H, 3JHH ) 9.0 Hz, 4JHF ) 5.5 Hz, o-C6H4F).
31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 31.4 and 32.4 (d,
2JPP′ ) 34.2 Hz). 13C{1H} NMR (75.4 MHz, CD3NO2, 298 K): δ
9.83 (m, PCH2CH3), 11.05 (s, C5(CH3)5), 22.39 (m, PCH2CH3),
31.22 and 32.96 (s, CH(COCH3)2), 40.24 (s, CH(COCH3)2), 75.39
(s, CH(Ar)), 104.4 (s, C5(CH3)5), 112.2 (s, RudCdCH), 116.5 (d,
3JCF ) 21.2 Hz, m-C6H4), 131.0 (d, 5JCF ) 8.2 Hz, o-C6H4), 140.8
(d, 4JCF ) 3.3 Hz, ipso-C6H4), 163.2 (d, 1JCF ) 243.1 Hz, p-C6H4),
Hz, JHbH7 ) 5.8 Hz, CH8aH8bCH2 ), 3.74 (dd, 1 H, JHaHb ) 17.1
3
3
3
7
2
3
Hz, JHbH4 ) 4.1 Hz, CH3aH3bCH4), 3.83 (sa, 1 H, CH4), 7.03 (vt,
3
3
3
2 H, JHH ) JHF ) 8.8 Hz, m-C6H4F), 7.22 (dd, 2 H, JHH ) 8.8
4
Hz, JHF ) 5.5 Hz, o-C6H4F). 31P{1H} NMR (161.89 MHz,
CD3NO2, 298 K): δ 31.3 and 31.8 (both d, 2JPP’ ) 35.4 Hz). 13C{1H}
NMR (75.4 MHz, CD3NO2, 298 K): δ 9.87 and 10.23 (m,
PCH2CH3), 11.37 (s, C5(CH3)5), 21.68-22.86 (m, PCH2CH3), 21.69,
28.50, and 37.69 (s, CH26,7,8), 32.82 (s, CH4), 60.90 (s, CH2 ), 103.7
3
(s, C5(CH3)5), 117.6 (s, C10), 116.3 (d, JCF ) 21.4 Hz, m-C6H4),
3
2
5
4
203.4 and 204.0 (s, CO), 343.1 (t, JCP ) 15.8 Hz, RudC). IR
130.4 (d, JCF ) 8.1 Hz, o-C6H4), 138.9 (d, JCF ) 2.8 Hz, ipso-
C6H4), 163.0 (d, 1JCF ) 244.5 Hz, p-C6H4), 167.0(s, C9), 198.5 (s,
C5), 290.7 (t, 2JCP ) 12.5 Hz, C2). IR (Nujol): ν(CO) 1650, ν(CdC)
(Nujol): ν(CO) 1715, ν(CdC) 1648 cm-1
.
Preparation of [Cp*Ru(C9H9O2R)(PEt3)2][BF4] (R ) p-MeO-
C6H4 (17), C6H5 (18), p-F-C6H4 (19)). A slight excess of 1,3-
cyclohexanedione (34 mg, 0.30 mmol) was added to a CH2Cl2
solution of the corresponding allenylidene complex 3-5 (0.25
mmol) at room temperature. After stirring for 30 min, the color
changed from dark brown to light orange. The mixture was
concentrated to less than 1 mL at reduced pressure. Addition of 10
mL of a 1:1 mixture of Et2O and petroleum ether caused the
precipitation of an orange solid, which was washed with petroleum
ether and dried under vacuum. Yield: 188 mg of 17 (92%), 185
mg of 18 (94%), 181 mg of 19 (90%).
1600 cm-1
.
Preparation of [Cp*Ru(C9H8O2Ph)(PEt3)2] (20). A 150 mg
(0.19 mmol) amount of carbene complex 18 was dissolved in 10
mL of THF, and then sodium methoxide (22 mg, 0.40 mmol) was
added. The mixture was stirred for 1 h, the solvent removed under
vacuum, and the residue dissolved in 10 mL of toluene. The
suspension was filtered through Celite to remove the resulting
NaBF4 salt and taken to dryness, giving a white solid. Yield: 113
mg (85%).
20: Anal. Calcd for C37H58O2P2Ru: C, 63.7; H, 8.38. Found: C,
1
63.7; H, 8.39. H NMR (400 MHz, C6D6, 298 K): δ 0.81-0.96
(m, 18 H, PCH2CH3), 1.59 (s, 15 H, C5(CH3)5), 1.65-2.23 (m, 12
H, PCH2CH3), 4.74 (d, 1 H, JH3H4 ) 5.0 Hz, CH4), 4.81 (d, 1 H,
3
3JH3H4 ) 5.0 Hz, CH3), 7.07 (t, 1 H, 3JHH ) 7.3 Hz, p-C6H5), 7.27
3
3
(t, 2 H, JHH ) 7.3 Hz, m-C6H5), 7.41 (d, 2 H, JHH ) 7.3 Hz,
o-C6H5). 31P{1H} NMR (161.89 MHz, C6D6, 298 K): δ 31.8 and
32.03 (both d, JPP′ ) 40.3 Hz). 13C{1H} NMR (75.4 MHz, C6D6,
2
298 K): δ 9.65 (s, PCH2CH3), 11.52 (s, C5(CH3)5), 21.74-22.25
(m, PCH2CH3), 21.33, 28.96, and 37.63 (s, CH26,7,8), 37.99 (s, C4),
91.86 (s, C5(CH3)5), 112.8 (s, C10), 116.9 (s, CH3), 125.1, 127.9,
128.1, and 149.3 (s, C6H5), 167.8 (s, C9), 178.4 (t, 2JCP ) 17.3 Hz,
17: Anal. Calcd for C38H61BF4O3P2Ru: C, 55.9; H, 7.54. Found:
C, 56.0; H, 7.55. 1H NMR (600 MHz, CDCl3, 298 K): δ 0.93-1.06
(m, 18 H, PCH2CH3), 1.65 (s, 15 H, C5(CH3)5), 1.68-1.94 (m, 12
C2), 195.9 (s, C5). IR (Nujol): ν(CO) 1717, ν(CdC) 1655 cm-1
.
7
6
H, PCH2CH3), 2.20 (m, 2 H, CH2 ), 2.38-2.43 (m, 2 H, CH2 ),
Preparation of [Cp*Ru{dCdCHCH(R)(CH3-C4H2O)}(PEt3)2]-
[BF4] (R ) C6H5 (21), p-F-C6H4 (22)). The corresponding alkenyl-
carbyne complex 8 or 9 (0.20 mmol) was dissolved in 5 mL of
CH2Cl2, giving a dark red solution. An excess of 2-methylfuran
(84 µL, 1.0 mmol) was added, and the mixture was stirred until
the dark red color completely disappears (4 h). The resulting orange
solution was filtered through Celite, taken to dryness, washed with
2 × 10 mL of Et2O, and finally dried under vacuum. Yield: 131
mg of 21 (87%), 141 mg of 22 (91%).
2
2.67 (m, 2 H, CH3aH3b + CH8aH8b), 2.88 (dt, 1 H, JHaHb ) 17.0
3
7
2
Hz, JHbH7 ) 5.0 Hz, CH8aH8bCH2 ), 3.54 (dd, 1 H, JHaHb ) 17.0
Hz, 3JHbH4 ) 5.0 Hz, CH3aH3bCH4), 3.71 (br s, 4 H, CH4 + CH3O
- C6H4), 6.75 (d, 2 H, 3JHH ) 9.0 Hz, m-C6H4), 6.93 (d, 2 H, 3JHH
) 9.0 Hz, o-C6H4). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K):
δ 31.2 and 31.6 (both d, JPP′ ) 35.0 Hz). 13C{1H} NMR (75.4
2
2
MHz, CD2Cl2, 298 K): δ 9.35 and 9.71 (d, JCP ) 3.0 Hz,
PCH2CH3), 11.14 (s, C5(CH3)5), 21.22-21.99 (m, PCH2CH3), 20.92,
27.69, and 37.01 (s, CH26,7,8), 31.54 (s, CH4)), 55.55 (s, CH3O)
60.23 (s, CH2 ), 102.6 (s, C5(CH3)5), 117.3 (s, C10), 114.2, 128.2,
3
21: Anal. Calcd for C36H57BF4OP2Ru: C, 57.2; H, 7.60. Found:
C, 57.3; H, 7.59. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.98-1.11
(m, 18 H, PCH2CH3), 1.78 (s, 15 H, C5(CH3)5), 1.68 and 1.98 (m,
12 H, PCH2CH3), 2.22 (s, 3 H, CH3-C4H2O), 4.54 (dt, 1 H, 3JHaHb
132.8, and 159.1 (s, C6H4), 164.8 (s, C9), 196.5 (s, C5), 290.3 (t,
2JCP ) 12.2 Hz, C2). IR (Nujol): ν(CO) 1715, ν(CdC) 1655 cm-1
.
18: Anal. Calcd for C37H59BF4O2P2Ru: C, 56.6; H, 7.57. Found:
C, 56.4; H, 7.55. 1H NMR (600 MHz, CD2Cl2, 298 K): δ 0.92-1.04
(m, 18 H, PCH2CH3), 1.63 (s, 15 H, C5(CH3)5), 1.67-1.94 (m, 12
4
3
) 10.7 Hz, JHP ) 1.5 Hz, dCdCHaCHb), 4.81 (d, 1 H, JHaHb
)
)
10.7 Hz, dCdCHaCHb), 6.34 and 6.40 (both d, 1 H each, JHH
3
3.0 Hz, CH3-C4H2O), 7.16, 7.24, and 7.31 (m, 5 H, C6H5). 31P{1H}
7
6
H, PCH2CH3), 2.17 (m, 2 H, CH2 ), 2.35-2.47 (m, 2 H, CH2 ),
2
2.66 (m, 2 H, CH3aH3b + CH8aH8b), 2.83 (dt, 1 H, JHaHb ) 17.0
2
NMR (161.89 MHz, CDCl3, 298 K): δ 32.1 and 32.3 (d, JPP′
)
35.0 Hz). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 9.32 and
Hz, JHbH7 ) 5.0 Hz, CH8aH8bCH2 ), 3.54 (dd, 1 H, JHaHb ) 17.0
3
7
2
2
Hz, 3JHbH4 ) 5.0 Hz, CH3aH3bCH4), 3.75 (sa, 1 H, CH4), 7.04 (d, 2
9.50 (d, JCP ) 3.8 Hz, PCH2CH3), 11.22 (s, C5(CH3)5), 14.00 (s,
CH3-C4H2O), 21.24 and 21.56 (d, 2JCP ) 6.0 Hz, PCH2CH3), 38.76
(s, CHPh), 103.3 (s, C5(CH3)5), 112.4 (s, RudCdCH), 106.5, 107.2,
151.7, and 155.5 (s, CH3-C4H2O), 127.4, 127.6, 129.1, and 142.1
3
3
H, JHH ) 7.3 Hz, o-C6H5), 7.18 (t, 1 H, JHH ) 7.3 Hz, p-C6H5),
7.25 (t, 2 H, 3JHH ) 7.3 Hz, m-C6H5). 31P{1H} NMR (161.89 MHz,
CD2Cl2, 298 K): δ 31.4 and 31.6 (both d, 2JPP′ ) 35.0 Hz). 13C{1H}
NMR (75.4 MHz, CD2Cl2, 298 K): δ 9.35 and 9.71 (d, 2JCP ) 3.0
Hz, PCH2CH3), 10.96 (s, C5(CH3)5), 21.15-21.75 (m, PCH2CH3),
2
(s, C6H5), 343.5 (t, JCP )14.5 Hz, RudC). IR (Nujol): ν(CdC)
1649 cm-1
.
20.80, 27.56, and 36.91 (s, CH26,7,8), 32.35 (s, CH4), 59.88 (s, CH2 ),
3
22: Anal. Calcd for C36H56BF5OP2Ru: C, 55.9; H, 7.30. Found:
102.6 (s, C5(CH3)5), 116.8 (s, C10), 127.1, 127.3, 128.8, and 141.1
C, 56.0; H, 7.30. 1H NMR (400 MHz, CD3NO2, 298 K): δ
(s, C6H5), 165.1(s, C9), 196.5 (s, C5), 291.0 (t, 2JCP ) 12.3 Hz, C2).
4
1.00-1.16 (m, 18 H, PCH2CH3), 1.87 (t, 15 H, JHP ) 1.1 Hz,
IR (Nujol): ν(CO) 1713, ν(CdC) 1653 cm-1
.
C5(CH3)5), 1.77 and 2.16 (m, 12 H, PCH2CH3), 2.23 (s, 3 H,
3
4
19: Anal. Calcd for C37H58BF5O2P2Ru: C, 55.3; H, 7.27. Found:
CH3-C4H2O), 4.79 (dt, 1 H, JHaHb ) 10.9 Hz, JHP ) 1.6 Hz,
3
1
C, 55.4; H, 7.28. H NMR (600 MHz, CD3NO2, 298 K): δ 1.02
RudCdCHaCHb), 5.00 (d,
RudCdCHaCHb), 6.93 (m, 2 H, CH3-C4H2O), 7.10 (vt, 2 H, 3JHH
) 3JHF ) 8.8 Hz, m-C6H4F), 7.38 (dd, 2 H, 3JHH ) 8.8 Hz, 4JHF
1
H, JHaHb
)
10.9 Hz,
and 1.09 (m, 18 H, PCH2CH3), 1.74 (s, 15 H, C5(CH3)5), 1.81 and
7
2.07 (m, 12 H, PCH2CH3), 2.19 (m, 2 H, CH2 ), 2.41 (m, 2 H,
)

1556 Organometallics, Vol. 28, No. 5, 2009
Pino-Chamorro et al.
Table 1. Crystal Data and Details of the Structure Determination of
compounds 4 and 6′
4
6′ · 2C6H5F
Crystal Data
formula
fw
C31H51BF4P2Ru
673.54
C101H80B2F48P2Ru · 2C6H5F
2582.48
cryst syst
space group
a, b, c [Å]
orthorhombic
P212121 (No. 19)
a ) 9.976(2)
b ) 10.613(2)
c ) 30.708(6)
R ) ꢀ ) γ ) 90
triclinic
P1 (No. 2)
j
a ) 14.050(3)
b ) 14.112(3)
c ) 30.307(6)
R ) 90.02(3)
ꢀ ) 102.82(3)
γ ) 108.58(3)
5537.2(19)
2
R, ꢀ, γ [deg]
V [Å3]
Z
3251.5(11)
4
1.376
0.623
Dcalc [g/cm3]
µ(Mo KR) [mm-1
F(000)
1.549
0.304
2604
]
1408
cryst size [mm]
Data Collection
temperature [K]
radiation [Å]
θ min, max [deg]
0.26 × 0.18 × 0.18
0.42 × 0.35 × 0.22
100
0.71073
2.0, 24.1
100
0.71073
1.4, 25.0
Figure 2. ORTEP view of the cation complex of
[Cp*Ru(t C-CHdCPh2)(PEt3)2][B(ArF)4]2 (ArF ) 3,5-(CF3)2C6H3)
(6′). Selected bond lengths (Å) and angles (deg): Ru(1)-P(1)
2.3730(12), Ru(1)-P(2) 2.3957(15), Ru(1)-C(11) 1.765(4),
C(11)-C(12) 1.382(5), C(12)-C(13) 1.380(5), C(13)-C(14)
1.469(5); C(13)-C(20) 1.464(5) P(1)-Ru(1)-P(2) 94.88(5),
Ru(1)-C(11)-C(12) 167.7(3), C(11)-C(12)-C(13) 127.6(4),
C(12)-C(13)-C(14) 122.6(4), C(12)-C(13)-C(20) 118.9(4),
C(14)-C(13)-C(20) 118.5(3).
data set (h,k,l intervals) -11:11; -11:12; -35:34 -16:13; -16:16; -36:35
tot, uniq data, R(int)
obsd data [I > 2.0σI] 4947
Refinement
20 932, 5109, 0.043
39 406, 19 314, 0.030
17663
Nref, Npar
5109, 282
0.0693, 0.1732a, 1.05
19314, 1547
0.0638, 0.1462, 1.04
0.002, 0.00
R, wR2a b, S
,
max and av shift/error 0.001, 0.000
min and max resd dens -0.49, 0.97
-0.57, 0.97
[e Å-3
]
a
w ) 1/[σ2(Fo ) + (0.0908P)2 + 10.8320P] where P ) (Fo + 2Fc2).
2
2
b
w ) 1/[σ2(Fo ) + (0.0530P)2 + 16.8513P] where P ) (Fo + 2Fc2).
2
2
Preparation of [Cp*Ru(C9H7O2Ar)(PEt3)2][BF4] (Ar ) C6H5
(24), p-F-C6H4 (25)). Compounds 24 and 25 were prepared by
addition of an excess of resorcinol (benzene-1,3-diol, 56 mg, 0.5
mmol) to a CH2Cl2 solution of the corresponding alkenylcarbyne
complex 7 or 8 (0.20 mmol), causing a fast color change from dark
red to light brown. The mixture was stirred for 1 h at room
temperature, then filtered through Celite, taken to dryness, washed
with 2 × 10 mL of Et2O, and finally dried under vacuum. Yield:
144 mg of 24 (92%), 142 mg of 25 (88%).
5.5 Hz, o-C6H4F). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ
32.1 and 32.3 (d, JPP′ ) 35.0 Hz). 13C{1H} NMR (75.4 MHz,
2
CD3NO2, 298 K): δ 9.62 and 10.05 (m, PCH2CH3), 11.25 (s,
C5(CH3)5), 13.68 (s, CH3-C4H2O), 22.20 and 22.52 (d, 2JCP ) 5.8
Hz, PCH2CH3), 38.99 (s, CHPh), 104.5 (s, C5(CH3)5), 112.8 (s,
RudCdCH), 107.5, 107.9, 153.0, and 157.0 (s, CH3-C4H2O),
116.5 (d, 3JCF ) 21.7 Hz, m-C6H4), 130.6 (d, 5JCF ) 8.2 Hz, o-C6H4),
4
1
140.3 (d, JCF ) 3.0 Hz, ipso-C6H4), 163.3 (d, JCF ) 243.1 Hz,
p-C6H4), 344.1 (t, 2JCP )15.4 Hz, RudC). IR (Nujol): ν(CdC) 1643
cm-1
.
Preparation of [Cp*Ru{dCdCHCH(p-C6H4-F)(C6H3(OC-
H3)2)}(PEt3)2][BF4] (23). The synthesis of the vinylidene compound
23 was carried out by addition of an excess of 1,3-dimethoxyben-
zene (134 µL, 1 mmol) to a CH2Cl2 solution of the corresponding
alkenylcarbyne 9 (0.20 mmol). The mixture was stirred for 6 h at
room temperature, then filtered through Celite, taken to dryness,
washed with 2 × 10 mL of Et2O, and finally dried under vacuum.
Yield: 146 mg (88%).
24: Anal. Calcd for C37H57BF4O2P2Ru: C, 56.7; H, 7.33. Found:
C, 56.8; H, 7.33. 1H NMR (400 MHz, CDCl3, 298 K): δ 1.00-1.09
(m, 18 H, PCH2CH3), 1.76 (s, 15 H, C5(CH3)5), 1.79 and 1.98 (m,
3
2
12 H, PCH2CH3), 2.43 (dd, 1 H, JH3aH4 ) 13.5 Hz, JH3aH3b
)
3
3
15.4 Hz, CH3a), 3.76 (dd, 1 H, JH3aH4 ) 13.5 Hz, JH4H3b ) 3.5
23: Anal. Calcd for C39H60BF5O2P2Ru: C, 56.5; H, 7.29. Found:
C, 56.5; H, 7.30. 1H NMR (400 MHz, CD3NO2, 298 K): δ
Hz, CH4), 3.93 (dd, 2JH3aH3b ) 15.4, 3JH3bH4 ) 3.5 Hz, CH3b), 6.49
3
3
(d, 1 H, JHH ) 8.5 Hz, CH5), 6.62 (dd, 1 H, JH5H6 ) 8.5 Hz,
4
1.02-1.13 (m, 18 H, PCH2CH3), 1.84 (t, 15 H, JHP ) 1.1 Hz,
4JH6H8 ) 2.3 Hz, CH6), 7.06 (d, 1 H, JH8H6 ) 2.3 Hz, CH8), 7.13
4
C5(CH3)5), 1.87 and 2.07 (m, 12 H, PCH2CH3), 3.78 and 3.85 (both
3
(d, 2 H, JHH ) 7.8 Hz, o-C6H5), 7.33 and 7.38 (m, 3 H, m- and
3
s, 3 H each, OCH3), 5.06 (d, 1 H, JHaHb ) 11.4 Hz, RudCd
p-C6H5). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 31.8 and
34.4 (d, 2 JPP’ ) 35.3 Hz). 13C{1H} NMR (75.4 MHz, CDCl3, 298
K): δ 9.24 (m, PCH2CH3), 11.21 (s, C5(CH3)5), 21.30 (m,
CHaCHb), 5.41 (d, 1 H, 3JHaHb ) 11.4 Hz, RudCdCHaCHb), 6.53
3
3
(m, 2 H, m-C6H3(OMe)2), 7.01 (vt, 2 H, JHH ) JHF ) 8.9 Hz,
m-C6H4F), 7.25 (d, 1 H, 2JHH ) 9.6 Hz, o-C6H3(OMe)2), 7.38 (dd,
2 H, 3JHH ) 8.9 Hz, 4JHF ) 5.5 Hz, o-C6H4F). 31P{1H} NMR (161.89
MHz, CDCl3, 298 K): δ 33.0 and 33.3 (d, 2 JPP′ ) 34.8 Hz). 13C{1H}
NMR (75.4 MHz, CD3NO2, 298 K): δ 9.50 (s, PCH2CH3), 11.12
(s, C5(CH3)5), 22.29 (m, PCH2CH3), 37.08 (s, CH(Ar)), 56.10 and
56.26 (s, OCH3), 104.1 (s, C5(CH3)5), 113.8 (s, RudCdCH), 99.51,
106.2, 127.1, 129.8, 158.4, and 161.2 (s, C6H3(OCH3)2), 116.1 (d,
3JCF ) 21.6 Hz, m-C6H4), 130.3 (d, 5JCF ) 8.0 Hz, o-C6H4), 143.1
(d, 4JCF ) 3.0 Hz, ipso-C6H4), 162.6 (d, 1JCF ) 242.0 Hz, p-C6H4),
PCH2CH3), 38.01 (s, CH4), 60.33 (s, CH2 ), 101.1 (s, C5(CH3)5),
3
127.7, 128.1, 129.2, and 140.3 (s, C6H5), 103.4, 107.8, 113.2 (s,
CH5,6,8), 117.6 (s, C10), 152.1 and 158.2 (s, C7 and C9), 290.3 (t,
2JCP ) 12.9 Hz, C2). IR (Nujol): ν (Ph) 1620, ν(OH) 3382 cm-1
.
25: Anal. Calcd for C37H56BF5O2P2Ru: C, 55.4; H, 7.04. Found:
1
C, 55.6; H, 7.07. H NMR (400 MHz, CD3NO2, 298 K): δ 1.09
(m, 18 H, PCH2CH3), 1.83 (s, 15 H, C5(CH3)5), 1.91 and 2.10 (m,
3
3
12 H, PCH2CH3), 2.68 (dd, 1 H, JH3aH4 ) 13.9 Hz, JH3aH3b
15.8 Hz, CH3a), 4.00 (m, 2 H, CH4 + CH3b), 6.58 (d, 1 H, 3JHH
)
)
344.8 (t, 2JCP ) 15.1 Hz, RudC). IR (Nujol): ν(CdC) 1643 cm-1
.
8.4 Hz, CH5), 6.62 (dd, 1 H, JH5H6 ) 8.5 Hz, JH6H8 ) 2.0 Hz,
3
4

Allenylidene/Alkenylcarbyne Synthesis and ReactiVity
Organometallics, Vol. 28, No. 5, 2009 1557
CH6), 6.82 (d, 1 H, JH8H6 ) 2.0 Hz, CH8), 7.14 (vt, 2 H, JHH
)
age.28 Most of non-hydrogen atoms were refined with anisotropic
displacement parameters. In compound 4, the pentamethylcyclo-
pentadienyl ligand, the ethyl groups in both phosphine ligands, and
the anion were disordered. In compound 6′ · 2C6H5F one ethyl group
in the phosphine ligand and solvate molecules were disordered.
The disorder was modeled splitting several atoms in two positions
and using restraints when it was necessary to kept bond lengths in
a reasonable chemical range. The hydrogen atoms were refined
using the SHELX riding model. The program ORTEP-329 was used
for plotting. CCDC 708293-708294 files giving crystallographic
data for 4 and 6′ · 2C6H5F are available free of charge via the
Internet at http://www.ccdc.cam.ac.uk/conts/retrieving.html or as
Supporting Information at http://pubs.acs.org.
4
3
3JHF ) 8.4 Hz, m-C6H4F), 7.30 (dd, 2 H, 3JHH ) 8.4 Hz, 4JHF ) 5.7
Hz, o-C6H4F). 31P{1H} NMR (161.89 MHz, CD3NO2, 298 K): δ
33.1 and 35.5 (d, JPP′ ) 34.9 Hz). 13C{1H} NMR (75.4 MHz,
2
CD3NO2, 298 K): δ 9.83 (m, PCH2CH3), 11.41 (s, C5(CH3)5), 22.28
(m, PCH2CH3), 38.11 (s, CH4), 61.00 (s, CH2 ), 103.8 (s, C5(CH3)5),
3
104.0, 113.2, and 121.0 (s, CH5,6,8), 116.8 (d, JCF ) 21.8 Hz,
3
m-C6H4), 129.7 (s, C10), 131.5 (d, JCF ) 8.2 Hz, o-C6H4), 137.9
5
(d, 4JCF ) 2.9 Hz, ipso-C6H4), 153.7 and 158.2 (s, C7 and C9), 163.4
(d, JCF ) 245.0 Hz, p-C6H4), 291.4 (t, JCP ) 13.5 Hz, C2). IR
1
2
(Nujol): ν(CdC) 1629, ν(OH) 3393 cm-1
.
X-ray Structure Determination. Suitable crystals for X-ray
diffraction analysis were obtained for compounds 4 and 6′ · 2C6H5F.
In each case a single crystal was mounted on a glass fiber to carry
out the crystallographic study. Crystal data and experimental details
are given in Table 1. X-ray diffraction data collections were
measured at 100 K on a Bruker Smart APEX CCD 3-circle
diffractometer using a sealed tube source and graphite-monochro-
mated Mo KR radiation (λ ) 0.71073 Å) at the Servicio Central
de Ciencia y Tecnolog´ıa de la Universidad de Ca´diz. Diffraction
data were recorded in four sets of frames over a hemisphere of the
reciprocal space by omega scans with δ(ω) 0.30 degrees and
exposure of 10 s per frame. Corrections for absorption and crystal
decay (insignificant) were applied by semiempirical methods from
equivalents using the program SADABS.27 The structures were
solved by direct methods, completed by subsequent difference
Fourier syntheses, and refined on F2 by full matrix least-squares
procedures using the programs contained in the SHELXTL pack-
Acknowledgment. We thank the Spanish “Ministerio de
Ciencia e Innovacio´n” (Project CTQ2007-60137/BQU and
“Juan de la Cierva” contract to E.B.) and “Junta de
Andaluc´ıa” (PAI-FQM188 and Project of Excellence PAI05
FQM094) for financial support and Johnson Matthey plc for
generous loans of ruthenium trichloride.
Supporting Information Available: CIF files giving crystal-
lographic data for 4 and 6′. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM801125F
(28) SHELXTL V. 6.10; Bruker-AXS: Madison, WI, 2000. Sheldrick,
G. M. SHELXS-86 and SHELXL-97; University of Go¨ttingen: Go¨ttingen,
Germany, 1997.
(27) Sheldrick, G. M. SADABS; University of Go¨ttingen: Go¨ttingen,
Germany, 2001.
(29) Faruggia, L. J. ORTEP-3 for Windows version 1.08. J. Appl.
Crystallogr. 1997, 30, 565.