Further chemistry of ruthenium alkenyl acetylide complexes: Routes to allenylidene complexes via a series of electrophilic addition reactions

Article abstract of DOI:10.1021/acs.organomet.0c00371

The methyl substituents in the cationic allenylidene complexes trans-[Ru{C=C=C(Me)R}Cl(dppe)₂]OTf ([1a?f]OTf) are readily deprotonated to give the corresponding alkenyl acetylide complexes trans-[Ru{C=CC(=CH₂)R}Cl(dppe)₂] (3; R = Me (a), Ph (b), ^cC₅H₁₀ (c), 4-MeS-C₆H₄ (d), ^cC₄H₃S (e), ^cC₅H₄N (f)). Similar chemistry is also observed from [Ru{C=C=C(Me)Ph}(dppe)Cp*]PF₆ ([2b]PF₆) and [Ru{C=C=C(Me)(4-MeS-C₆H₄)}(dppe)Cp*]PF₆([2b]PF₆), chosen to broaden the reaction scope, giving [Ru{C= CC(=CH₂)Ph}(dppe)Cp*] (4b) and [Ru{C=C=C(CH₂)(4-MeS-C₆H₄)}(dppe)Cp*] (4d). In turn, reactions of 3b,d and 4b,d with the [BF₄]^? salt of the electrophilic tritylium [CPh₃]⁺ cation give the functionalized allenylidene complexes trans-[Ru{C=C=C(CH₂CPh₃)R}Cl(dppe)₂]BF₄ ([5b,d]BF₄) and [Ru{C=C=C(CH₂CPh₃)R}(dppe)Cp*]BF₄ ([6b,d]BF₄) formed by addition of the electrophile to the remote vinylic carbon (C(δ)). Although trans-[Ru{C=C=C(CH₂CPh₃)Me}Cl(dppe)₂]BF₄ ([5a]BF₄) could not be successfully purified from reactions of 3a with [CPh₃]BF₄, deprotonation of the crude product gave the Zaitsev vinyl product trans-[Ru{C=CC(=CHCPh₃)Me}Cl(dppe)₂] (7a) in good yield. The initial cycloheptatrienyl adducts formed from reactions of 3b,d and 4b,d with the tropylium salt [C₇H₇]BF₄ undergo a ring-contraction process in chloroform solutions upon exposure to air, to give the styrene-like products trans-[Ru{C=C=C(R)C(H)=CHPh}Cl(dppe)₂]BF₄ ([10b,d]BF₄) and [Ru{C=C= C(R)C(H)=CHPh}(dppe)Cp*]BF₄ ([11b,d]BF₄), through what is believed to be a radical mechanism mediated by triplet oxygen.

Full text of DOI:10.1021/acs.organomet.0c00371

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Further Chemistry of Ruthenium Alkenyl Acetylide Complexes:
Routes to Allenylidene Complexes via a Series of Electrophilic
Addition Reactions
Michael R. Hall, Marcus Korb, Stephen A. Moggach, and Paul J. Low*
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ABSTRACT: The methyl substituents in the cationic allenylidene
complexes trans-[Ru{CCC(Me)R}Cl(dppe)2]OTf ([1a−f]OTf)
are readily deprotonated to give the corresponding alkenyl acetylide
complexes trans-[Ru{CCC(CH2)R}Cl(dppe)2] (3; R = Me (a),
Ph (b), cC5H10 (c), 4-MeS-C6H4 (d), cC4H3S (e), cC5H4N (f)). Similar
chemistry is also observed from [Ru{CCC(Me)Ph}(dppe)Cp*]-
PF6 ([2b]PF6) and [Ru{CCC(Me)(4-MeS-C6H4)}(dppe)Cp*]-
PF6([2b]PF6), chosen to broaden the reaction scope, giving [Ru{C
CC(CH2)Ph}(dppe)Cp*] (4b) and [Ru{CCC(CH2)(4-MeS-
C6H4)}(dppe)Cp*] (4d). In turn, reactions of 3b,d and 4b,d with the
[BF4]− salt of the electrophilic tritylium [CPh3]+ cation give the
functionalized allenylidene complexes trans-[Ru{CCC(CH2CPh3)-
R}Cl(dppe)2]BF4 ([5b,d]BF4) and [Ru{CCC(CH2CPh3)R}(dppe)Cp*]BF4 ([6b,d]BF4) formed by addition of the
electrophile to the remote vinylic carbon (C(δ)). Although trans-[Ru{CCC(CH2CPh3)Me}Cl(dppe)2]BF4 ([5a]BF4) could
not be successfully purified from reactions of 3a with [CPh3]BF4, deprotonation of the crude product gave the Zaitsev vinyl product
trans-[Ru{CCC(CHCPh3)Me}Cl(dppe)2] (7a) in good yield. The initial cycloheptatrienyl adducts formed from reactions of
3b,d and 4b,d with the tropylium salt [C7H7]BF4 undergo a ring-contraction process in chloroform solutions upon exposure to air,
to give the styrene-like products trans-[Ru{CCC(R)C(H)CHPh}Cl(dppe)2]BF4 ([10b,d]BF4) and [Ru{CC
C(R)C(H)CHPh}(dppe)Cp*]BF4 ([11b,d]BF4), through what is believed to be a radical mechanism mediated by triplet oxygen.
Scheme 1. Selegue’s Allenylidene Synthesis12
INTRODUCTION
■
Transition-metal allenylidene complexes, [M(CCCR1R2)-
Ln], have long been a source of interest in organometallic
chemistry, being compatible with a diverse range of substituents,
(R1, R2) and transition-metal fragments (MLn).1−5 These
complexes have in turn been not only investigated for their
fundamental electronic structures and chemical reactivities but
also explored within the context of a wide range of applications
from molecular electronics6,7 and nonlinear optics8 to catalysis.9
As such, allenylidene ligands have come to be recognized as an
important motif in the family of carbon-rich organometallic
complexes.10,11
Despite this broad interest in allenylidene complexes, the
synthetic route developed by Selegue’s group involving
elimination of water from propargylic alcohols within a metal
coordination sphere remains the primary route to obtaining
allenylidene complexes (Scheme 1).12
Although different routes suitable for the formation of specific
Received: May 29, 2020
allenylidene complexes and related derivatives from various
precursors other than propargylic alcohols are of interest,5 few
widely applicable practical alternatives have been developed,
which is especially apparent for the late transition metals. With
ambitions to further broaden synthetic routes to allenylidene
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complexes, it should be noted that cationic methylallenylidene
complexes are reversibly deprotonated at C(δ) to give alkenyl
acetylide complexes (Scheme 2).13 This facile acid−base
Scheme 4. Formation of Selegue’s γ-Vinylvinylidene
Complex via a γ-Hydroxyvinylidene Intermediate14
Scheme 2. Methylallenylidene/Alkenyl Acetylide
Protonation Equilibria13
chemistry suggests that alkenyl acetylide complexes may serve
as precursors for allenylidene complexes through addition of
electrophiles other than protons to C(δ).
In considering the reactivity profiles of methyl-substituted
allenylidene complexes, Selegue’s initial attempts at the
synthesis of [Ru(CCCMe2)(PPh3)2Cp]PF6 by reaction
of [RuCl(PPh3)2Cp] with HCCC(OH)Me2 (A) and
NH4PF6 are informative (Scheme 3).14,15 The initially formed
γ-hydroxyvinylidene can eliminate water via either of two
pathways, to give products featuring allenylidene or vinyl-
vinylidene ligands, which in turn react together to give the
observed bimetallic product (Scheme 3). Support for the
vinylvinylidene elimination product has been obtained from a
similar reaction of [RuCl(PMe3)2Cp] with 1-ethynylcyclohex-
anol (C) (Scheme 4).14
More recently, Rigaut has incorporated ruthenium alkenyl
acetylide complexes in the synthesis of alkenyl carbyne
complexes via an intermediate methylallenylidene species
(Scheme 5).13 The reaction of trans-[Ru{CCC(CH2)R}-
Cl(dppe)2] (R = Me, Ph) with HBF4·Et2O initially gave the
corresponding methylallenylidene complex trans-[Ru{CC
C(Me)R}Cl(dppe)2]BF4, which gave the carbyne species trans-
[Ru{CC(H)C(Me)R}Cl(dppe)2][BF4]2 on further pro-
tonation.
[RuCl(dppe)2]OTf (Chart 1).12 The organic substituents on
the allenylidene ligands were chosen to sample across a range of
chemical space, including Selegue’s dimethylallenylidene ligand
([1a]OTf), the electroneutral phenyl group ([1b]OTf), and the
cyclic alkyl fragment C6H10 ([1c]OTf), which was obtained as a
mixture of the vinylidene and allenylidene species, consistent
with prior observations (Schemes 3 and 4).14 The ligands
bearing the thioanisole ([1d]OTf), thiophenyl ([1e]OTf), and
pyridyl ([1f]OTf) groups capable of binding to metallic surfaces
were also introduced with a view to later work with allenylidene-
based molecular wires in molecular junctions, which will be
reported elsewhere.7,16−19 To demonstrate the generality of the
reactions that follow, the representative half-sandwich com-
plexes [Ru{CCC(Me)Ph}(dppe)Cp*]PF6 ([2b]PF6) and
[Ru{CCC(Me)(4-MeS-C6 H4 )}(dppe)Cp*]PF6
([2d]PF6) were also prepared from [RuCl(dppe)Cp*] and the
respective propargylic alcohols B and D in the presence of
NH4PF6.
In this work, we show that the formation of allenylidene
complexes from alkenyl acetylide complexes is a general process
for a range of carbon-based electrophiles via facile C−C bond
forming reactions, permitting the formation of a range of
functionalized allenylidene complexes in a simple manner.
RESULTS AND DISCUSSION
The reactions generally proceed smoothly to give the desired
methyl allenylidene complexes as the OTf− salts (Scheme 1 and
Chart 1). In contrast to Selegue’s more reactive [Ru(CC
CMe2)(PPh3)2Cp]+ system, complex [1a]OTf was isolated as
■
The methylallenylidene precursor complexes [1a−f]OTf were
sought via the Selegue route from the appropriate propargylic
alcohol (A−F) and the unsaturated ruthenium complex
15
Scheme 3. Proposed Mechanism of In Situ Dimerization of [Ru{CCCMe2}(PPh3)2Cp]+
B
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[1c]OTf as an approximate 1:1 mixture with the vinylvinylidene
[1c′]OTf (Scheme 6). The allenylidene [1c]PF6 was detected in
Scheme 5. Rigaut’s Synthesis of Ruthenium Carbyne
Complexes from an Alkenyl Acetylide Precursor via a
Methylallenylidene Intermediate (R = Me, Ph)13
Scheme 6. Water Elimination Pathways from the γ-
Hydroxyvinylidene Intermediate Affording an Allenylidene
a
[1c]+ and γ-Vinylvinylidene [1c′]+ Product Mixture
Chart 1. Precursor Propargylic Alcohols A−F and Derived
a
Allenylidene Complexes [1]OTf and [2]PF6
a
Deprotonation gives the corresponding alkenyl acetylide complex 3c.
the product mixture by the observation of allenylidene C(α),
C(β), and C(γ) carbon resonances in the 13C{1H} NMR
spectrum at 320.9, 200.4, and 184.2 ppm, respectively, as well as
a strong ν(CCC) IR band at 1950 cm−1 and a 31P{1H}
NMR resonance at 40.5 ppm. The vinylvinylidene [1c′]OTf
gave rise to a ν(CC) IR band at 1617 cm−1 and a 31P{1H}
NMR resonance at 41.7 ppm. These products are likely formed
from two different water elimination steps from the presumed
initially formed γ-hydroxyvinylidene in the manner proposed
earlier by Selegue to account for the bimetallic product in
Scheme 3.14 Here, the dimerization reaction is suppressed, likely
due to the greater steric congestion of the carbon chains in [1c]+
and [1c′]+. Further treatment of the crude mixture with t-BuOK
in THF resulted in the formation of the alkenyl acetylide species
3c as the single product (Scheme 6) (vide infra).
The deeply colored compounds [1a−e]OTf, [2b]PF6, and
[2d]PF6 were characterized by the typical, strong ν(CCC)
bands of allenylidene complexes between 1920 and 1950 cm−1
and 31P{1H} NMR resonances in the range 40−42 ppm for [1a−
e]OTf and 78−79 ppm for [2b]PF6 and [2d]PF6 as well as the
appropriate molecular ions in the ESI or APCI mass spectra. The
allenylidene nature of the unsaturated ligand was further
established from the observation of resonances in the 13C{1H}
NMR spectra near 290 (C(α), JCP ≈ 16 Hz), 200 (C(β)), and
160 (C(γ)) ppm.
a
Note: F directly gives the alkenyl acetylide complex 3f (vide infra).
the discrete monomeric dimethylallenylidene trans-[Ru(C
CCMe2)Cl(dppe)2]OTf, consistent with previous observa-
tions concerning the isolation of the analogous BF4 salt.20
In contrast to reactions of [RuCl(dppe)2]OTf with A−E, the
reaction of [RuCl(dppe)2]OTf with the 4-pyridyl-function-
−
However, the reaction of [RuCl(dppe)2]OTf with C gave
C
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alized propargylic alcohol HCCC(OH)(Me)(4-cC6H4N) (F)
gave the alkenyl acetylide trans-[Ru{CCC(CH2)-
(4-cC5H4N)}Cl(dppe)2] (3f), likely a consequence of deproto-
nation of the methyl group in the initially formed methyl-
allenylidene [1f]OTf by the basic pyridyl substituent in situ
(Scheme 7).
The alkenyl acetylide character of the carbon-rich ligands in
complexes 3 and 4 was clearly established from IR spectroscopy,
with the strong allenylidene ν(CCC) band of the
precursors [1]OTf and [2]PF6 being replaced by weaker
ν(CC) and ν(CC) bands in the products (ca. 2050 and
1580 cm−1). The methylene protons of the alkenyl acetylide
ligands were detected as resonances near 5.30 and 4.80 ppm,
while the carbon atoms of the carbon-rich ligand gave rise to
13C{1H} NMR resonances near 125.00 (C(α), JCP ≈ 16 Hz),
115.00 (C(β)), 109.00 (C(γ)), and 110.00 (C(δ)) ppm. The
31P{1H} NMR resonances near 50 ppm (3)21 and 81 ppm
(4)22,23 are characteristic of acetylide complexes of the
respective metal fragments.
Scheme 7. In Situ Deprotonation of Transient Allenylidene
[1f]+ Affording 3f
The deprotonation/reprotonation chemistry illustrated in
Scheme 2 prompted a consideration of reactions of alkenyl
acetylide complexes such as 3 and 4 with electrophilic reagents.
By way of initial investigation, each of the representative
compounds 3b,d and 4b,d were allowed to react with
[CPh3]BF4, from which the functionalized allenylidene
complexes [5b]BF4, [5d]BF4, [6b]BF4, and [6d]BF4 were
isolated and purified by preparative TLC (acetone/hexane 3/7)
(Scheme 9). The re-formation of the allenylidene ligand motif
Scheme 9. Functionalization of Ru Complexes 3 and 4 by
Reaction with [CPh3]BF4, Giving Allenylidene Complexes
a
[5]BF4 and [6]BF4
The facile formation of 3c from [1c]+ and [1c′]+ (Scheme 6),
as well as the reaction of [RuCl(dppe)2]OTf with F to give 3f
and observed acidic character of other methyl allenylidene
complexes (Scheme 2), prompted further consideration of this
chemistry. The alkenylacetylide complexes 3a−e and 4b,d were
subsequently prepared by deprotonation of the appropriate
allenylide precursors [1a,b,d,e]OTf, [2b]PF6, and [2d]PF6 with
t-BuOK in THF and purified by elution through a plug of basic
alumina (Scheme 8).
a
−
The BF4 counterion is omitted from the scheme for clarity.
Scheme 8. Deprotonation of Allenylidenes [1]+ and [2]+ to
Give Alkenylacetylide Complexes 3 and 4
a
was clearly demonstrated by the strong ν(CCC) band in
each of the substituted products and the three 13C{1H} NMR
resonances characteristic of this cumulated moiety. In addition,
the methylene (CH2) protons were readily observed near 4.0−
3.2 ppm, while the positive ion ESI-MS contained an ion with
mass and isotope pattern consistent with the proposed cation in
each case.
In an effort to extend this chemistry, compound 3a, which
offers a second methyl group and hence the potential for an
additional deprotonation/electrophilic addition process, was
treated with [CPh3]BF4 to give a crude mixture that could not be
purified but presumably contained the tritylium adduct trans-
[Ru{CCC(CH2CPh3)Me}Cl(dppe)2]BF4 ([5a]BF4),
given the strong IR band at 1940 cm−1 and observation of the
molecular ion (m/z 1246.3571) in the ESI(+)-MS spectrum of
the crude material.
The treatment of crude [5a]BF4 with base and subsequent
purification gave the Zaitsev product 7a in 59% isolated yield
(Scheme 10), which was identified spectroscopically and further
characterized by single-crystal X-ray diffraction (vide infra). The
facile formation of the Zaitsev product precludes the use of
a
[1a−e]+: [Ru] = RuCl(dppe)2; R = Me (a), Ph (b), 4-MeS-C6H4
(d), 2′-cC4H3S (e). [2b,d]+: [Ru] = Ru(dppe)Cp*; R = Ph (b), 4-
MeS-C6H4 (d).
In this manner, the vinyl(methyl) acetylide complex 3a
proved stable to isolation and characterization, free of the
dimerization chemistry described earlier involving the {Ru-
(PPh3)2Cp} analogue. Deliberate attempts to form an analogue
of the Selegue dimer shown in Scheme 3 by the reaction of 3a
with [1a]OTf in CH2Cl2 were ultimately unsuccessful, again
likely a consequence of the steric bulk of the {RuCl(dppe)2}
moiety and congestion at C(α).
D
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Scheme 10. Formation of [5a]BF4 and Potential
Deprotonation Pathways (t-BuOK in THF): (i) Hofmann
Product (Disfavored); (ii) Zaitsev Product 7a (Favored)
Scheme 12. Formation of Products [10]BF4 and [11]BF4
from the Proposed Oxygen-Promoted Ring Contraction of
Methylcycloheptatrienyl-Functionalized Allenylidene
a
Complexes [8]BF4 and [9]BF4
[1a]OTf as a reagent for the preparation of doubly substituted
allenylidene complexes, for which the Hofmann-style product
would be required on the second deprotonation step (Scheme
10). Regardless, a consideration of the crystallographic structure
of 7a shows significant steric congestion at the terminal C(γ)
carbon, which would likely inhibit further reactions at the chain
terminus.
The use of tritylium as an electrophile prompted further
considerations of other carbon-based electrophiles such as
tropylium ([C7H7]+). Tropylium (or cycloheptatrienyl) de-
rivatives have been employed previously by others in the
synthesis of cumulated ligands, albeit for purposes different from
those in this study, with examples of cycloheptatrienylidene-
functionalized allenylidene complexes being known. However,
these are strongly polarized toward the alkynyl resonance forms,
with the tropylium group offering further η-bonding capacity
(Scheme 11).24,25 The use of cycloheptatriene as an ancillary
a
−
The BF4 counterion is omitted from the scheme for clarity.
ions of an appropriate mass for the molecular ions in the mass
spectra appeared, efforts to isolate these compounds ultimately
failed. Rather, the complexes [10b,d]BF4 and [11b,d]BF4
resulting from ring contraction of the cycloheptatriene
substituent were observed to form in CDCl3 solutions of the
crude product over the course of approximately 1 h. On a
preparative scale, the crude tropylium addition products were
stirred in CHCl3 exposed to air at 40 °C for 2 h. The ring-
contracted products were subsequently purified by preparative
TLC (acetone/hexane 3/7) and crystallization (Scheme 12).
The ring contraction of methylcycloheptatriene to styrene has
been observed previously and the rate constant of the thermal
rearrangement processes in the gas phase studied.28 Related
processes have also been observed in the interconversion of
toluene and cycloheptatrienyl cations.29 It is also noted that
tropylium has been employed as an electrophile in carbon−
carbon bond forming reactions for a range of organometallic
precursors, with the addition of tropylium to the β-carbon of
ruthenium acetylide compounds to give the corresponding
cycloheptatrienylvinylidene complexes being particularly well
established,30−32 although no further rearrangement is observed
in these cases.
Scheme 11. Resonance Structures Illustrating the
Allenylidene vs Polarized Acetylide Resonance Forms of a
Dinuclear Fe(II)−Cr(0)
(Cycloheptatrienylidene)ethenylidene-Bridged Complex25
ligand in organometallic chemistry is of course well
documented, with a wealth of cycloheptatrienyl half-sandwich
complexes having been synthesized and studied.26,27
Reactions of 3b,d and 4b,d with the tropylium salt [C7H7]BF4
were therefore undertaken to further explore the breadth of the
electrophilic addition chemistry (Scheme 12). Although the
expected cycloheptatrienyl adducts [8b,d]+ and [9b,d]+ were
detected in solution from 31P{1H} NMR resonances in the
ranges 38−42 ppm ([8b,d]+) and 77−80 ppm ([9b,d]+) and
In each case the product structures [10b,d]BF4 and[11b,d]-
BF4 were established from key spectroscopic data, including the
presence of both ν(CCC) and ν(CC) bands in the IR
spectrum and the characteristic, as well as mutually coupled,
3
(E)-alkene proton resonances near 6.5 and 6.7 ppm with JHH
coupling constants of ∼13 Hz. The 13C{1H} NMR spectrum
was especially informative, with resonances clearly observed for
both allenylidene and vinyl fragments of the ligand, being readily
assigned from the 1H−13C HSQC 2D spectra. The observation
E
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of the molecular ion in ESI(+) and APCI(+) mass spectra and
fragment ions consistent with the loss of styrene further support
the formation of the rearrangement product for these
allenylidene complexes. Minor impurities detected in samples
of [10d]BF4, [11b]BF4, and [11d]BF4 were not investigated
due to their low abundance but likely correspond to structural
(e.g. E/Z) isomers formed from the cycloheptatrienyl internal
ring contraction.
Given the requirement for exposure to air in order for
conversion to occur efficiently, the reaction is likely initiated by
the formation of a radical intermediate resulting from H-atom
abstraction by triplet oxygen (Scheme 13). A related rearrange-
Scheme 13. Proposed Mechanism for a Cycloheptatrienyl to
Styryl Ring Contraction, Exemplarily Shown for the Reaction
Figure 2. ORTEP drawing (50% probability level) of acetylide complex
3b with selected atoms labeled. The phenyl rings of the dppe ligands as
well as selected hydrogen atoms have been omitted for clarity.
a
of [8b]+ to Give[10b]+
a
Counterions are omitted for clarity.
Figure 3. ORTEP drawing (50% probability level) of acetylide complex
3d with selected atoms labeled. The phenyl rings of the dppe ligand as
well as selected hydrogen atoms and one molecule of dichloromethane
have been omitted for clarity.
ment process is also seen in the formation of some gold carbenes,
with the reaction of substituted cycloheptatriene with cationic
gold complexes resulting in the extrusion of benzene and the
formation of the gold carbenoid species Au{CR}L+ via an
intermediate and mechanism similar to that proposed in Scheme
13.33
Molecular Structures. The molecular structures of the
propargylic alcohol HCCC(OH)(Me)(4-MeS-C6H4) (D)
(Figure 1), the alkenyl acetylides 3b (Figure 2) and 3d (Figure
Figure 1. ORTEP drawing (50% probability level) of D showing the
atom-labeling scheme. A second molecule of the asymmetric unit and
selected hydrogen atoms have been omitted for clarity.
Figure 4. ORTEP drawing (30% probability level) of acetylide complex
7a with selected atoms labeled. The phenyl rings of the dppe ligands as
well as selected hydrogen atoms and two molecules of dichloromethane
have been omitted for clarity.
3), the Zaitzev product 7a (Figure 4), and the ring-contracted
allenylidene product [10b]BF4 (Figure 5) were determined by
single-crystal X-ray diffraction. In each case the structures are
entirely consistent with the proposals made on the basis of the
IR and NMR spectroscopic and mass spectrometric data. Strong
intermolecular interactions were only observed for alkyne D,
where the packing reveals a tetrameric arrangement based on
hydrogen bridge bonds between hydroxyl functionalities of
adjacent molecules (Supporting Information).
F
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ruthenium acetylide complexes (Table 1).34,35 Equally, the
alternating long/short/long bond lengths along the Ru−C1−
C2−C3 chain are consistent with the structural parameters of
similar ruthenium alkynyl complexes.23
The shorter Ru−C1 bond length found in [10b]+ (1.902(4)
Å) in comparison with those in 3b (2.0100(17) Å) and 3b
(2.020(3) Å) reflects the metal−carbene interaction in
allenylidene complexes.7 The more limited C1−C2−C3 bond
length alternation also clearly supports the description of the
chain as an allenylidene and is similar to the case for other
ruthenium allenylidene complexes within the {RuCl(dppe)2}
coordination sphere.6,36,37 The C4−C11 bond length of
1.337(6) Å in [10b]+ is typical for a CC double bond,
supporting the description of the ring-contracted moiety in
terms of a styrene-like fragment. The latter was predominantly
formed as the E isomer (see above), which is almost in a plane
(6.5°) with the cumulene π system. The presence of the
positively charged allenylidene motif in [10b]+ is accompanied
by a shortening of the trans-Ru−Cl bond from >2.4702(4) to
2.4428(2) Å, due to the decreased trans influence, caused by the
increased Ru−C back-bonding.
Figure 5. ORTEP drawing (50% probability level) of the allenylidene
cation [10b]+ with selected atoms labeled. The phenyl rings of the dppe
ligands as well as selected hydrogen atoms and the BF4 anion have
−
been omitted for clarity.
CONCLUSIONS
■
The differences in the unsaturated C1−C2−C3 carbon chains
in propargylic alcohol D, acetylide complexes (3b,d, 7a) and
allenylidene complex ([10b]+) are clearly demonstrated by an
examination of differences in the respective C−C bond lengths
of each structure. The modest elongation of the C1−C2 bond
length in the acetylide complexes (3b, 1.215(3) Å; 3d, 1.192(4)
Å; 7a, 1.199(6) Å) in comparison with the precursor alkyne D
(1.178(3) Å) is entirely consistent with the established trends of
A series of allenylidene and alkenyl acetylide complexes based on
the trans-{RuCl(dppe)2} and {Ru(dppe)Cp*} fragments have
been prepared. Treatment of examples of the alkenyl acetylide
species with bulky carbon-based electrophiles results in addition
at C(δ) to give a variety of functionalized allenylidene complexes
via C−C bond formation. In the case of cycloheptratrienyl-
substituted derivatives, obtained using tropylium [C7H7]+, an
Table 1. Selected Bond Lengths (Å) and Angles (deg) from the Crystallographically Determined Structures of Propargylic
Alcohol D, the Acetylides 2b,d and 7a, and the Allenylidene Cation [10b]+
a
D
3b
3d
7a
[10b]+
Bond Distances
C1−C2
C2−C3
C3−C4
C3−C5
1.178(3)
1.177(3)
1.481(2)
1.480(2)
1.525(2)
1.530(2)
1.523(2)
1.530(2)
1.215(3)
1.441(3)
1.330(3)
1.495(3)
1.192(4)
1.451(4)
1.325(4)
1.490(4)
1.199(6)
1.443(5)
1.350(5)
1.510(6)
1.531(5)
1.235(5)
1.371(5)
1.446(6)
1.490(6)
C4−C6
C4−C11
C11−C12
Ru−P
1.337(6)
1.461(6)
2.3980(8)
2.4284(2)
2.4428(2)
1.902(4)
b
2.3232(5)
2.3819(5)
2.4702(4)
2.0100(17)
2.3448(8)
2.3761(7)
2.4958(7)
2.020(3)
2.3322(10)
2.3921(9)
2.4878(10)
2.007(4)
Ru1−Cl1
Ru1−C1
Bond Angles (deg)
Ru1−C1−C2
C1−C2−C3
175.48(16)
171.5(2)
172.7(3)
171.6(3)
177.2(3)
172.2(4)
178.3(3)
171.8(4)
176.60(19)
177.18(19)
C2−C3−C4
C2−C3−C5
120.17(19)
118.56(17)
119.8(3)
118.3(3)
117.8(4)
115.2(3)
121.2(4)
112.94(14)
109.84(15)
C3−C4−C6
C3−C4−C11
C4−C11−C12
130.7(4)
118.4(3)
127.2(4)
a
b
Data from two independent molecules in the unit cell. The minimum and maximum values are given.
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residue was washed with saturated NH4Cl solution and extracted with
EtOAc (3 × 30 mL), the extract was washed with brine (30 mL), dried
over MgSO4, and filtered, and then the solvent removed with a rotary
evaporator. The crude product was then purified by silica column
chromatography (hexane/EtOAc 9/1).
unanticipated ring contraction into styryl groups occurred
rapidly (∼1 h), mediated by triplet oxygen. The ready
deprotonation/electrophilic addition chemistry permitting
conversion between the allenylidene and acetylide function-
alities is presented as a fairly general route to functionalized
allenylidene complexes and other carbon-rich ligands.
Synthesis of HCCC(OH)(Me)Ph (B).
EXPERIMENTAL DETAILS
■
All reactions were performed under an atmosphere of nitrogen
employing standard Schlenk techniques in oven-dried glassware.
Unless stated otherwise, no particular care was taken to exclude air
upon workup of the reaction products. Solvents were dried by literature
methods or with an Innovative Technologies Solvent Purification
System and sparged with nitrogen before use. For chromatography,
silica gel was used as received and alumina (basic) was oven-dried (100
°C) overnight before use.
This compound was prepared from TMSA (3.26 mL, 22.9 mmol), n-
BuLi (9.16 mL, 22.9 mmol), acetophenone (2.67 mL, 22.9 mmol), and
K2CO3 (1.088 g, 7.87 mmol) in the manner described above. Cooling
the product fraction in a freezer after purification gave a white
crystalline solid (1.3 g, 8.9 mmol, 39%). 1H NMR (CDCl3 500 MHz)
δ/ppm: 7.55 (m, 2H, H6/7); 7.26 (m, 2H, H6/7); 7.19 (m, 1H, H8); 2.56
(s, 1H, H1); 2.42 (s, 1H, OH); 1.68 (s, 3H, H4). 13C{1H} NMR (CDCl3
500 MHz) δ/ppm: 145.1 (s, C5); 128.5 (s, C6/7); 128.0 (s, C8); 125.0
(s, C6/7); 87.4 (s, C3); 73.2 (s, C1); 69.7 (s, C2); 33.2 (s, C4). IR ATR/
cm−1: 3288 ν(OH); 3269 ν(CCH); 2110 ν(CC). ESI(+)-MS m/
z: calculated for [M + H]+ ([C10H10O + H]+) 147.0810, observed
147.0672 [M + H]+.
The compounds HCCC(OH)(Me)R (R = Ph,38 4-MeS-C6H4,38
2-cC4H3S,39 4-cC5H4N39), [RuCl(dppe)2]OTf,21 [Ru{CCC-
(Me)R}Cl(dppe)2]OTf (R = Me,20 Ph40), [C7H7]BF4,41 and [CPh3]-
41
BF4 were prepared either in accordance with, or with slight
refinements to, existing literature procedures. All other chemicals
were purchased and used as received.
The various 1H, 13C{1H}, 31P{1H}, and 19F{1H} NMR spectra were
recorded on a Varian 400 MHz (1H, 399.86 MHz; 13C, 100.6 MHz; 31P,
161.9 MHz), Bruker 500 MHz (1H, 500.10 MHz; 13C, 125.8 MHz; 31P,
202.4; 19F{1H}, 470.4 MHz), and Bruker 600 MHz (1H, 600.10 MHz;
13C, 150.9 MHz; 31P, 242.9; 19F{1H}, 564.7 MHz) spectrometers at
Synthesis of HCCC(OH)(Me)(4-MeS-C6H4) (D).
1
room temperature. Chemical shifts in H and 13C{1H} spectra are
referenced against the residual protio solvent peaks.42−44 Unless stated
otherwise, 31P{1H} and 19F{1H} chemical shifts are reported relative to
conventional standards (85% H3PO4; CFCl3).45 Cr(acac)3 was used as
a relaxation agent in the acquisition of the allenylidene carbon
resonances C(α), C(β), and C(γ) of several allenylidene complexes for
13C{1H} NMR.46,47
This compound was prepared from TMSA (3.80 mL, 26.7 mmol), n-
BuLi (11.4 mL, 28.5 mmol), 4-acetylthioanisole (4.32 g, 26.0 mmol),
and K2CO3 (2.18 g, 15.8 mmol) in the manner described above.
Purification gave the product as a yellow solid (2.60 g, 13.5 mmol,
52%). Single crystals suitable for X-ray diffraction were obtained from
For all NMR spectra, multiplets are reported according to their
closest first-order approximation. For all NMR assignments, Ho, Hm,
and Hp refer to the ortho, meta, and para protons of the phenyl rings of
the ancillary phosphine ligands, respectively, while Ci, Co, Cm, Cp
similarly refer to the ipso, ortho, meta, and para carbons of these same
phenyl rings. IR spectra were recorded on an Agilent Cary 630 FTIR
spectrometer using ATR or in transmission mode from solutions
between CaF2 plates. Mass spectra were obtained from a Waters Liquid
Chromatograph Premier Mass Spectrometer, using positive mode
electrospray ionization (ESI(+) and ESI(−)) or atmospheric pressure
chemical ionization (APCI(+)). Samples were prepared in MeCN or
MeOH and inserted by direct injection via the on-board injector.
Single-Crystal X-ray Diffraction Analysis. Crystallographic data
for the structures were collected on a Rigaku-Oxford Diffraction
Gemini, Xcalibur diffractometer with graphite-monochromated Mo Kα
radiation (λ = 0.71073 Å) (D, 3b,d, 7a) at ≤120 K and a Synergy-S
([10b]BF4) X-ray diffractometer with mirror-monochromated Cu Kα
radiation (λ = 1.54184 Å) at 150 K using a PhotonJet X-ray Source. The
data were corrected for Lorentz and polarization effects and absorption.
The structures were solved by direct methods and refined against F2
with full-matrix least-squares using the program suite SHELX.48,49
Anisotropic displacement parameters were employed for the non-
hydrogen atoms. All hydrogen atoms were added at calculated positions
and refined by use of a riding model with isotropic displacement
parameters based on those of the parent atom.
General Procedure for Propargylic Alcohol Synthesis. A
solution of (trimethylsilyl)acetylene (TMSA) in THF (60 mL) was
cooled to −78 °C and then treated with n-BuLi (1.5 equiv) and stirred
at −78 °C for 1 h. After this time, the appropriate ketone (1 equiv) was
added to the reaction mixture which was stirred for a further 1 h, before
the reaction mixture was warmed to room temperature and stirred
overnight. The reaction mixture was quenched with saturated NH4Cl
solution and extracted with EtOAc (3 × 30 mL). The crude product
was then charged with MeOH (50 mL) with K2CO3 (0.6 equiv) and
stirred overnight. The solvent was removed under reduced pressure, the
1
the slow evaporation of a hexane solution of the material. H NMR
(CDCl3 500 MHz) δ/ppm: 7.57 (app d, JHH = 8.6 Hz, 2H, H7); 7.25
(app d, JHH = 8.6 Hz, 2H, H6); 2.67 (s, 1H, H1); 2.49 (s, 3H, SMe); 2.33
(s, 1H, OH); 1.77 (s, 3H, H4). 13C{1H} NMR (CDCl3 500 MHz) δ/
ppm: 142.0 (s, C5); 138.1 (s, C8); 126.5 (s, C6); 125.5 (s, C7); 87.2 (s,
C3); 73.2 (s, C1); 69.6 (s, C2); 33.1 (s, SMe); 15.9 (s, C4). IR ATR/
cm−1: 3302 ν(OH); 3284 ν(CCH); 2114 ν(CC); 1593 ν(CC).
ESI(+)-MS m/z: calculated for [M + H]+ ([C11H12OS + H]+)
193.0687, observed 193.0489 [M + H]+.
Synthesis of HCCC(OH)(Me)(2-cC4H3S) (E).
This compound was prepared from TMSA (5.1 mL, 36.5 mmol), n-
BuLi (13.2 mL, 33.0 mmol), 2-acetylthiophene (3.6 mL, 33.3 mmol),
and K2CO3 (2.9 g, 21.0 mmol) in the manner described above. The
1
product was obtained as a yellow oil (1.50 g, 9.85 mmol, 30%). H
NMR (CDCl3 600 MHz) δ/ppm: 7.26 (dd, JHH = 1.3, 5.1 Hz, 1H, H7);
7.21 (dd, JHH = 1.3, 3.6 Hz, 1H, H6); 6.56 (dd, JHH = 3.6, 5.1 Hz, 1H,
H8); 2.68 (s, 1H, H1); 2.57 (s, 1H, OH); 1.91 (s, 3H, H4). 13C{1H}
NMR (CDCl3 600 MHz) δ/ppm: 149.6 (s, C5); 126.8 (s, C8); 125.4 (s,
C7); 124.3 (s, C6); 86.6 (s, C2); 72.7 (s, C1); 67.3 (s, C3); 33.1 (s, C4).
IR ATR/cm−1: 3418 ν(OH); 3289 ν(CCH); 2111 ν(CC); 1517
ν(CC). ESI(+)-MS m/z: calculated for [M + H]+ ([C8H8OS + H]+)
153.0374, observed 153.0071 [M + H]+.
H
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Synthesis of HCCC(OH)(Me)(4-cC5H4N) (F).
ESI(+)-MS m/z: calculated for [M]+ ([C62H56ClP4Ru]+) 1061.2065,
observed 1061.2057 [M]+.
Synthesis of trans-[Ru{CCC(cC5H10)}Cl(dppe)2]OTf ([1c]OTf).
This compound was prepared from TMSA (16.3 mL, 115.0 mmol), n-
BuLi (5.8 mL, 155.0 mmol), 4-acetylpyridine (3.75 mL, 33.9 mmol),
and K2CO3 (2.88 g, 20.8 mmol) in the manner described above.
Purification gave the product as a pale yellow solid (2.75 g, 18.7 mmol,
55%). 1H NMR (CDCl3 500 MHz) δ/ppm: 8.56 (app d, JHH = 6.2 Hz,
2H, H6/7); 7.55 (app d, JHH = 6.2 Hz, 2H, H6/7); 3.56 (s, OH); 2.68 (s,
H1); 1.76 (s, 3H, H4). 13C{1H} NMR (CDCl3 500) δ/ppm: 154.3 (s,
C5); 149.9 (s, C6/7); 120.1 (s, C6/7); 86.2 (s, C3); 73.7 (s, C1); 68.9 (s,
C2); 33.1 (s, C4). IR ATR/cm−1: 3230 ν(CCH); 2111 ν(CC);
1603 ν(CC). ESI(+)-MS m/z: calculated for [M]+ ([C9H9NO]+)
147.0684, observed 147.0641 [M]+.
General Procedure for Preparation of Allenylidenes [1a−
e]OTf, [2b]PF6, and [2d]PF6. The appropriate propargylic alcohol
HCCC(OH)(Me)R and [RuCl(dppe)2]OTf were charged with
CH2Cl2 (60 mL), and the reaction mixture was stirred at room
temperature overnight. After this time, the solvent was removed under
reduced pressure, the residue was redissolved in minimal CH2Cl2, and
this solution was then filtered into stirred Et2O (20 mL) to give a
precipitate. The precipitate was collected by vacuum filtration and
washed with hexane (2 × 10 mL).
This compound was prepared from [RuCl(dppe)2]OTf (0.506 g,
0.0467 mmol) and 1-ethynylcyclohexanol (C) (0.123 g, 0.0990 mmol)
as described above. Workup gave a brown powder (0.49 g, 0.041 mmol,
1
88%). H and 31P{1H} NMR analysis indicated the presence of both
vinylidene and allenylidene products, with resonances in the 31P{1H}
NMR spectrum at 41.67 and 40.53 ppm showing roughly a 1/1 mixture
of the vinylidene and the allenylidene, respectively, consistent with
previously published observations.14 Difficulties with purification
precluded full characterization of the allenylidene complex [1c]OTf.
1H NMR (CDCl3 600 MHz) δ/ppm: 7.45−7.02 (m, 40H, dppe); 2.96
(m, 4H, dppe); 2.70 (m, 4H, dppe); 1.70 (m, 2H, CH2); 1.64 (m, 4H,
CH2); 1.49 (m, 2H, CH2); 1.30 (m, 2H, CH2). 31P{1H} NMR (CDCl3
600 MHz) δ/ppm: 40.53 (s, dppe). 19F{1H} NMR (CDCl3 400 MHz)
δ/ppm: −78.08 (s, OTf). IR ATR ν/cm−1: 1950 ν(CCC); 1264
ν(OTf). APCI(+)-MS m/z: calculated for [M]+ ([C60H58ClP4Ru − Cl
− H + MeCN]+) 1044.2720, observed 1044.2737 [M − Cl − H +
MeCN]+.
Synthesis of trans-[Ru{CCC(Me)(4-MeS-C6H4)}Cl(dppe)2]OTf
Synthesis of trans-[Ru(CCCMe2)Cl(dppe)2]OTf ([1a]OTf).
([1d]OTf).
This compound was prepared from [RuCl(dppe)2]OTf (0.543 g, 0.050
mmol) and 2-methyl-3-butyn-2-ol (A) (0.1 mL, 0.10 mmol) as
described above. Workup gave [1a]OTf as a yellow-brown powder
(0.50 g, 0.43 mmol, 87%). 1H NMR (CDCl3 600 MHz) δ/ppm: 7.40−
7.03 (m, 45H, C6H5 + Ph, dppe); 2.96 (m, 4H, dppe); 2.72 (m, 4H,
dppe); 1.27 (6H, H4). 13C{1H} NMR (CDCl3 600 MHz) δ/ppm:
320.0 (m, C1); 202.2 (s, C2); 174.8 (s, C3); 133.8 (m, Co, dppe); 133.2
(m, Co, dppe); 132.2 (m, Ci, dppe); 132.0 (m, Ci, dppe); 131.1 (s, Cp,
dppe); 130.5 (s, Cp, dppe); 128.5 (m, Cm, dppe); 128.0 (m, Cm, dppe);
35.9 (s, C4); 29.5−29.2 (m, dppe). 31P{1H} NMR (CDCl3 500 MHz)
δ/ppm: 41.65 (s, dppe). 19F{1H} NMR (CDCl3 500 MHz) δ/ppm:
−77.98 (OTf). IR ATR/cm−1: 3055 ν(CC); 1953 ν(CCC);
1264 ν(OTf). ESI(+)-MS m/z: calculated for [M]+ ([C57H54ClP4Ru −
Cl − H + MeCN]+) 1004.2407, observed 1004.2496 [M − Cl − H +
MeCN]+.
This compound was prepared from [RuCl(dppe)2]OTf (0.613 mg,
0.0566 mmol) and HCCC(OH)(Me)-4-MeS-C6H4 (D) (0.218 mg,
1.13 mmol) as described above. Workup gave [1d]OTf as a deep purple
powder (0.70 g, 0.0567 mmol, 98%). 1H NMR (CDCl3 500 MHz) δ/
ppm: 7.26 (m, 8H, dppe, Hp); 7.14 (m, 8H, dppe, Ho); 7.00−7.04 (m,
24H, dppe, Hm + Ho); 6.93 (app d, JHH = 8.5 Hz, H6); 6.82 (app d, JHH
=
8.5 Hz, H7); 3.06 (m, 4H, dppe); 2.82 (m, 4H, dppe); 2.51 (s, 3H,
SMe); 1.73 (s, 3H, H4). 13C{1H} NMR (CDCl3 600) δ/ppm: 299.0
(pent, JCP = 14.0 Hz, C1); 199.9 (s, C2); 161.2 (s, C3); 148.4 (s, C5);
139.2 (s, C8); 133.8 (s, Co, dppe); 133.2 (s, Co, dppe); 132.6 (p, Ci,
dppe); 132.2 (p, Ci, dppe); 131.1 (s, Cp, dppe); 130.0 (s, Cp, dppe);
128.9 (s, C6); 128.6 (s, Cm, dppe); 127.9 (s, Cm, dppe); 125.2 (s, C7);
30.7 (s, C4); 29.1 (m, dppe); 14.7 (s, SMe). 31P{1H} NMR (CDCl3 600
MHz) δ/ppm: 40.64 (s, dppe). 19F{1H} NMR (CDCl3 600 MHz) δ/
ppm: −77.86 (s, OTf). IR ATR/cm−1: 1928 ν(CCC); 1261
ν(OTf). APCI(+)-MS m/z: calculated for [M]+([C63H58ClP4Ru]+)
1107.1942, observed 1107.2069 [M]+.
Synthesis of trans-[Ru{CCC(Me)Ph}Cl(dppe)2]OTf ([1b]OTf).
Synthesis of trans-[Ru{CCC(Me)(2-cC4H3S)}Cl(dppe)2]OTf
([1e]OTf).
This compound was prepared from [RuCl(dppe)2]OTf (0.511 g,
0.0472 mmol) and 2-phenyl-3-butyn-2-ol (B) (0.141 g, 0.0964 mmol)
as described above. Workup gave [1b]OTf as a red powder (0.51 g,
1
0.042 mmol, 89%). H NMR (CDCl3 500 MHz) δ/ppm: 7.68−7.00
(m, 45H, C6H5 + Ph, dppe); 3.08 (m, 4H, dppe); 2.84 (m, 4H, dppe);
1.67 (s, 3H, H4). 13C{1H} NMR (CDCl3 500 MHz) δ/ppm: 309.7 (m,
C1); 208.7 (s, C2); 162.6 (s, C3); 142.4 (s, C5); 133.7 (m, Co, dppe);
133.2 (m, Co, dppe); 133.1 (s, C8); 132.4 (m, Ci, dppe); 131.8 (m, Ci,
dppe); 131.2 (s, Cp, dppe); 130.4 (s, Cp, dppe); 129.4 (s, C6/7); 128.7
(m, Cm, dppe); 128.3 (s, C6/7); 127.9 (m, Cm, dppe); 31.8 (s, C4);
29.1−28.8 (m, dppe). 31P{1H} NMR (CDCl3 500 MHz) δ/ppm: 40.36
(s, dppe). 19F{1H} NMR (CDCl3 600 MHz) δ/ppm: −77.91 (OTf). IR
ATR/cm−1: 3054 ν(CC); 1934 ν(CCC); 1266 ν(OTf).
HCCC(OH)(Me)(2-cC4H3S) (E) (0.095 mg, 0.0624 mmol) was
charged with CH2Cl2 (40 mL) and sparged for 10 min. [RuCl-
(dppe)2]OTf (0.405 mg, 0.0374 mmol) was added and the mixture
stirred for 48 h, giving a red-violet solution. Workup gave [1e]OTf as a
1
violet powder (0.450 g, 0.037 mmol, 99%). H NMR (CDCl3 500
MHz) δ/ppm: 7.91 (d, JHH = 4.6 Hz, 1H, H6/8); 7.29−7.02 (m, 41H, H7
+ Ph, dppe); 6.24 (d, JHH = 4.6 Hz, 1H, H6/8); 3.05 (m, 4H, dppe); 2.84
(m, 4H, dppe); 1.63 (s, 3H, H4). 13C{1H} NMR (CDCl3 600 MHz) δ/
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ppm: 290.1 (m, C1); 196.3 (s, C2); 153.0 (s, C3); 151.01 (s, C5); 139.1
(s, thienyl); 132.8 (m, Ci, dppe); 132.2 (m, Ci, dppe); 133.2 (s,
thienyl); 130.9 (s, thienyl); 133.8 (m, Co, dppe); 133.3 (m, Co, dppe);
131.1 (s, Cp, dppe); 130.4 (s, Cp, dppe); 128.6 (m, Cm, dppe); 127.9
(m, Cm, dppe); 31.2 (s, C4); 29.6−29.4 (m, dppe). 31P{1H} NMR
(CDCl3 600 MHz) δ/ppm: 41.79 (s, dppe). 19F{1H} NMR (CDCl3
600 MHz) δ/ppm: −77.90 (s, OTf). IR ATR/cm−1: 1926 ν(CC
C); 1260 ν(OTf). APCI(+)-MS m/z: calculated for [M]+
([C60H54ClP4RuS]+) 1067.1629, observed 1067.1643 [M]+.
400 MHz) δ/ppm: 78.52 (s, dppe); − 144.28 (sept, PF6). IR ATR/
cm−1: 1928 ν(CCC); 835 ν(PF6). ESI(+)-MS m/z: calculated for
[M]+ ([C47H49P2RuS]+) 809.2074, observed 809.2044 [M]+.
General Procedure for the Synthesis of Alkenyl Acetylides
3a−f and 4b,d. The appropriate allenylidene complex and t-BuOK
(1.2 equiv) were charged with THF (40 mL) and stirred for 2 h. After
this time, the solvent was removed under reduced pressure and the
residue eluted with CH2Cl2/Et2O (1/1) through a pad of basic alumina
(3 × 2.5 cm). The solvent was removed using a rotary evaporator, after
which the residue was dissolved in the minimum volume of CH2Cl2 and
precipitated with pentane or hexane, and then the precipitate was
collected by vacuum filtration and washed with hexane.
Synthesis of [Ru{CCC(Me)Ph}(dppe)Cp*]PF6 ([2b]PF6).
Synthesis of trans-[Ru{CCC(CH2)Me}Cl(dppe)2] (3a).
A Schlenk flask was charged with 2-phenyl-3-butyn-2-ol (B) (0.235 mg,
1.61 mmol), [RuCl(dppe)Cp*] (0.503 g, 0.0751 mmol), and NH4PF6
(0.241 g, 1.48 mmol) in MeOH (40 mL) and the solution stirred at
room temperature overnight. The resulting red-brown solution was
filtered, the solvent was removed under reduced pressure, the resulting
residue was dissolved in a minimum volume of CH2Cl2, and the product
was precipitated by the addition of Et2O (50 mL). The precipitate was
collected by vacuum filtration, washed with hexane, and air-dried to give
This compound was prepared from [Ru(CCCMe2)Cl(dppe)2]-
OTf ([1a]OTf) (0.503 g, 0.44 mmol) and t-BuOK (0.053 g, 0.047
mmol) as described above. Workup gave 3a as a bright yellow solid
(0.39 g, 0.39 mmol, 89%). 1H NMR (CDCl3, 600 MHz) δ/ppm: 7.70
(m, 8H, Co, dppe); 7.23 (app t, JHH = 7.3 Hz, 4H, Cp, dppe); 7.16 (app t,
J
HH = 7.4 Hz, 4H, Cp, dppe); 7.09 (m, 8H, Co, dppe); 7.06 (app t, JHH =
7.6 Hz, 6H, Cm, dppe); 6.95 (app t, JHH = 7.6 Hz, 8H, Cm, dppe); 4.59
(app d, JHH = 2.8 Hz, 1H, H4a/b); 4.38 (app d, JHH = 2.8 Hz, 1H, H4a/b);
2.74 (m, 4H, dppe); 2.59 (m, 4H, dppe); 1.57 (s, 3H, C4). 13C{1H}
NMR (CDCl3 600 MHz) δ/ppm: 137.1 (m, Ci, dppe); 135.5 (m, Ci,
dppe); 134.7 (m, Co, dppe); 134.3 (m, Co, dppe); 132.2 (s, C3); 129.1
(s, Cp, dppe); 128.7 (s, Cp, dppe); 127.3 (m, Cm, dppe); 126.9 (m, Cm,
dppe); 120.72 (pent, JCP = 15.4 Hz, C1); 116.19 (s, C2); 110.75 (s, C4);
30.9 (m, dppe); 24.62 (s, C5). 31P{1H} NMR (CDCl3 600 MHz) δ/
ppm: 50.27 (s, dppe). IR ATR/cm−1: 2046 ν(CC); 1585 ν(CC).
ESI(+)-MS m/z: calculated for [M]+ ([C57H53ClP4Ru − Cl +
MeCN]+) 1004.2407, observed 1004.2457 [M − Cl + MeCN]+.
Synthesis of trans-[Ru{CCC(CH2)Ph}Cl(dppe)2] (3b).
1
[2b]PF6 as a brown powder (0.58 g, 0.064 mmol, 85%). H NMR
(CDCl3 400 MHz) δ/ppm: 7.51−7.13 (m, 25H, Ph + dppe); 2.86 (m,
2H, dppe); 2.60 (m, 2H, dppe); 1.65 (s, 3H, H4); 1.60 (s, 15H, Cp*).
13C{1H} NMR (CDCl3 400 MHz) δ/ppm: 293.2 (m, C1); 201.96 (s,
C2); 155.8 (C3); 142.3 (s, C5); 134.6−134.5 (m, Ci, dppe); 134.0−
133.9 (m, Ci, dppe); 132.9 (s, C8); 132.6 (t, JHH = 5.3 Hz, Co, dppe);
132.3−132.0 (m, Co, dppe); 131.4 (s, Cp, dppe); 131.1 (s, Cp, dppe);
129.5 (s, C6); 129.0−128.9 (m, Cm, dppe); 128.6−128.5 (m, Cm,
dppe); 127.3 (s, C7); 102.4 (s, Cp*); 30.3 (s, C4); 30.2 (m, dppe); 10.2
(s, Me of Cp*). 31P{1H} NMR (CDCl3 400 MHz) δ/ppm: 79.00 (s,
dppe); −143.65 (sept, PF6). IR ATR/cm−1: 1930 ν(CCC); 831
ν(PF6). ESI(+)-MS m/z: calculated for [M]+ ([C46H47P2Ru]+)
763.2196, observed 763.2195 [M]+.
Synthesis of [Ru{CCC(Me)(4-MeS-C6H4)}(dppe)Cp*]PF6
([2d]PF6).
This compound was prepared from trans-[Ru{CCC(Me)(Ph)}-
Cl(dppe)2]OTf ([1b]OTf) (0.498 g, 0.411 mmol) and t-BuOK (0.050
g, 0.446 mmol) as described above. Workup gave 3b as a yellow-orange
solid (0.27 g, 0.026 mmol, 62%). Single crystals suitable for X-ray
diffraction were grown by layering a CH2Cl2 solution of 3b with
MeOH. 1H NMR (CDCl3 400 MHz) δ/ppm: 7.74 (m, 8H, Ho, dppe);
7.20−6.92 (m, 37H, Ho + Hm + Hp + Ph, dppe); 5.21 (app d, JHH = 1.9
Hz, 1H, H4a/b); 4.69 (app d, JHH = 1.9 Hz, 1H, H4a/b); 2.76 (m, 4H,
dppe); 2.59 (m, 4H, dppe). 13C{1H} NMR (CDCl3 400 MHz) δ/ppm:
141.8 (s, C3), 136.7 (m, Ci, dppe); 135.6 (m, Ci, dppe); 134.9 (m, Co,
dppe); 134.6 (s, Ph); 134.2 (m, Co, dppe); 129.3 (s, Cp, dppe); 127.7 (s,
Ph); 127.5 (m, Cm, dppe); 126.9 (m, Cm, dppe); 126.8 (s, Ph); 126.5 (s,
Ph); 124.6 (pent, JCP = 15.1 Hz, C1); 114.7 (s, C2); 112.3 (s, C4); 30.9−
30.6 (m, dppe). 31P{1H} NMR (CDCl3 400 MHz) δ/ppm: 50.02 (s,
dppe). IR ATR/cm−1: 2051 ν(CC). APCI(+)-MS m/z: calculated
for [M]+ ([C62H55ClP4Ru − Cl + MeCN]+) 1066.2563, observed
1066.2589 [M − Cl + MeCN]+.
A Schlenk flask was charged with HCCC(OH)(Me)(4-MeS-C6H4)
(D) (0.185 g, 0.963 mmol), [RuCl(dppe)Cp*] (0.343 g, 0.512 mmol),
and NH4PF6 (0.155 g, 0.951 mmol) in CH2Cl2 (40 mL) and the
reaction mixture stirred overnight. The resulting purple solution was
filtered, the solvent was removed under reduced pressure, and the
residue was redissolved in the minimum volume of CH2Cl2. Addition of
Et2O (50 mL) caused precipitation of [2d]PF6, which was collected by
vacuum filtration, washed with hexane, and air-dried, giving a purple
1
powder (0.25 g, 0.26 mmol, 51%). H NMR (CDCl3 400 MHz) δ/
ppm: 7.48 (app d, JHH = 8.0 Hz, 2H, H6/7); 7.43 (t, JHH = 7.2 Hz, 4H,
Ho, dppe); 7.30−7.24 (m, 12H, Hm/p/o, dppe); 7.16 (t, JHH = 8.6 Hz,
4H, Hm, dppe); 7.00 (app d, JHH = 8.0 Hz, 2H, H6/7); 2.89 (m, 2H,
dppe); 2.59 (m, 2H, dppe); 2.48 (s, 3H, SMe); 1.67 (s, 3H, H4); 1.95
(s, 15H, Cp*). 13C{1H} NMR (CDCl3 400 MHz) δ/ppm: 286.4 (t, JCP
= 18.3 Hz, C1); 195.6 (s, C2); 155.2 (s, C3); 146.9 (s, C5/8); 138.8 (s,
C5/8); 134.6 (m, Ci, dppe); 134.1 (m, Ci, dppe); 132.7−132.6 (m, Co,
dppe); 132.3 (t, JHH = 5.2 Hz, Co, dppe); 131.3 (s, Cp, dppe); 131.0 (s,
Cp, dppe); 128.8 (t, JHH = 4.9 Hz, Cm, dppe); 128.5 (t, JHH = 5.2 Hz, Cm,
dppe); 127.9 (s, C6/7); 125.6 (s, C6/7); 101.8 (s, Cp*); 30.2 (m, dppe);
29.6 (s, C4); 14.8 (s, SMe); 10.2 (s, Me of Cp*). 31P{1H} NMR (CDCl3
Synthesis of trans--[Ru{CC(cC6 H9)}Cl(dppe)2] (3c).
This compound was prepared from trans-[Ru{CCC(cC5H10)}Cl-
(dppe)2]OTf ([1b]OTf, 0.44 g, 0.37 mmol) and t-BuOK (0.050 g, 0.45
mmol) as described above. Workup gave 3c as a bright yellow solid
(0.35 g, 0.34 mmol, 91%). 1H NMR (CDCl3 600 MHz) δ/ppm: 7.77
J
https://dx.doi.org/10.1021/acs.organomet.0c00371
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
(m, 8H, Ho, dppe); 7.22 (t, JHH = 7.3 Hz, 4H, Hp, dppe); 7.14 (t, JHH
=
Synthesis of trans-[Ru{CCC(CH2)(4-cC5H4N)}Cl(dppe)2] (3f).
7.3, 4H, Hp, dppe); 7.03 (m, 16H, Ho + Hm, dppe); 6.93 (t, JHH = 7.6
Hz, 8H, Hm, dppe); 5.17 (app t, 1H, H4); 2.72 (m, 4H, dppe); 2.58 (m,
4H, dppe); 2.06 (m, 2H, CH2); 1.79 (m, 2H, CH2); 1.55 (m, 4H, CH2).
13C{1H} NMR (CDCl3 600 MHz) δ/ppm: 137.4 (pent, JCP = 10.0 Hz,
Ci, dppe); 135.6 (pent, JCP = 10.0 Hz, Ci, dppe); 134.9 (m, Co, dppe);
134.3 (m, Co, dppe); 129.0 (s, Cp, dppe); 128.6 (s, Cp, dppe); 127.2 (s,
Cm, dppe); 126.9 (s, Cm, dppe); 126.0 (s, C2); 123.5 (s, C4); 116.7 (s,
C3); 113.8 (pen., JCP = 15.6 Hz, C1); 31.0 (m, dppe); 30.4 (s, CH2);
25.9 (s, CH2); 23.4 (s, CH2); 22.8 (s, CH2). 31P{1H} NMR (CDCl3
600 MHz) δ/ppm: 50.24 (s, dppe). IR ATR/cm−1: 2051 ν(CC).
ESI(+)-MS m/z: calculated for [M]+ ([C60H57ClP4Ru − Cl +
MeCN]+) 1044.2720, observed 1044.2762 [M − Cl + MeCN]+.
Synthesis of trans-[Ru{CCC(CH2)(4-MeS-C6H4)}Cl(dppe)2]
(3d).
A solution of [RuCl(dppe)2]OTf (0.503 g, 0.465 mmol) and HC
CC(OH)(Me)(4-cC5H4N) (F) (0.122 g, 0.829 mmol) in CH2Cl2 (40
mL) was prepared and stirred overnight. Infrared measurements taken
of the reaction solution showed almost full conversion to the alkenyl
acetylide, indicated by the presence of a strong band at 2047 cm−1
typical of ruthenium alkynyl complexes. The reaction solvent was
removed and the residue eluted through a basic alumina plug using
CH2Cl2/Et2O (1/1). Solvent was removed by a rotary evaporator, and
the solid residue was washed with hexane (2 × 10 mL) and air-dried.
The sample of 3f so obtained as a yellow-brown powder (0.37 g, 0.35
mmol, 75%) also contained trace amounts of the corresponding
bis(alkynyl) species, evidenced by a 31P{1H} NMR resonance at 51.66
ppm.50,51 1H NMR (CDCl3 400 MHz) δ/ppm: 8.16 (d, JHH = 6.2 Hz,
2H, H6/7); 7.61−6.86 (m, 40H, dppe); 6.81 (d, JHH = 6.2 Hz, 2H, H6/7);
5.37 (app d, JHH = 1.5 Hz, 1H, H4a/b); 4.83 (app d, JHH = 1.5 Hz, 1H,
H4a/b); 2.74 (m, 4H, dppe); 2.60 (m, 4H, dppe). 13C{1H} NMR
(CDCl3 400 MHz) δ/ppm: 149.3 (s, C5); 134.8−134.7 (m, Co, dppe);
134.6 (s, C6/7); 134.2 (m, Co, dppe); 129.4 (s, Cp, dppe); 129.0 (s, C2);
128.8 (s, Cp, dppe); 127.5 (m, Cm, dppe); 127.0 (m, Cm, dppe); 121.3
(s, C6/7); 114.12 (s, C4); 30.8−30.5 (m, dppe). 31P{1H} NMR (CDCl3
600 MHz) δ/ppm: 49.07 (s, dppe). IR ATR/cm−1: 2050 ν(CC).
APCI(+)-MS m/z: calculated for [M]+ ([C61H54ClNP4Ru − Cl +
MeCN]+) 1067.2516, observed 1067.2573 [M − Cl + MeCN]+;
calculated for [Ru{CCC(CH2)C5H4N}2(dppe)2 + H]+
1155.2892; observed 1155.2829.
This compound was prepared from [Ru{CCC(Me)(4-MeS-
C6H4)}Cl(dppe)2]OTf ([1d]OTf, 0.503 g, 0.0400 mmol) and t-
BuOK (0.053 g, 0.047 mmol) as described above. Workup gave 3d as a
red-purple powder (0.25 g, 0.23 mmol, 56%). Single crystals suitable for
X-ray diffraction were grown by layering a CH2Cl2 solution of 3d with
MeOH. 1H NMR (CDCl3 500 MHz) δ/ppm: 7.71−7.70 (m, 8H, Ho,
dppe); 7.13−7.19 (m, 10H, H6/7 + Hm, dppe); 7.04−7.05 (m, 8H, Hp,
dppe); 6.89−6.99 (m, 18H, H6/7 + Ho + Hm, dppe); 5.19 (app d, JHH
=
Synthesis of [Ru{CCC(CH2)Ph}(dppe)Cp*] (4b).
1.8 Hz, 1H, H4a/b); 4.69 (app d, JHH = 1.8 Hz, 1H, H4a/b); 2.76 (m, 4H,
dppe); 2.57 (m, 4H, dppe); 2.44 (s, 3H, SMe). 13C{1H} NMR (CDCl3
600 MHz) δ/ppm: 139.0 (s, C3); 136.7 (m, Ci, dppe); 136.0 (s, C8);
135.7 (m, Ci, dppe); 135.1 (s, C5); 134.9 (m, Co, dppe); 134.2 (m, Co,
dppe); 129.3 (s, Cp, dppe); 128.6 (s, Cp, dppe); 127.5 (m, Cm, dppe);
127.2 (s, C6/7); 126.9 (m, Cm, dppe); 126.3 (s, C6/7); 125.1 (m, C1);
114.4 (s, C2); 111.6 (s, C4); 30.7 (m, dppe); 16.4 (s, SMe). 31P{1H}
NMR (CDCl3 600 MHz) δ/ppm: 49.47 (s, dppe). IR ATR/cm−1: 2049
ν(CC). APCI(+)-MS m/z: calculated for [M]+ ([C63H57ClP4Ru −
Cl + MeCN]+) 1112.2720, observed 1112.2414 [M − Cl + MeCN]+.
Synthesis of trans-[Ru{CCC(CH2)(2-cC4H3S)}Cl(dppe)2] (3e).
This compound was prepared from [Ru{CCC(Me)(Ph)}(dppe)-
Cp*]PF6 ([2b]OTf) (0.522 g, 0.575 mmol) and t-BuOK (0.065 g, 0.58
mmol) as described in the general description above. Workup gave 4b
as a flocculent, bright orange solid (0.32 g, 0.42 mmol, 73%). 1H NMR
(CDCl3, 400 MHz) δ/ppm: 7.73 (t, JHH = 8.2 Hz, 4H, Ho, dppe); 7.37−
7.28 (m, 14H), 7.19 (t, JHH = 8.1 Hz, 4H, Ho, dppe); 7.10−7.02 (m,
4H); 5.25 (app d, JHH = 1.8 Hz, H4a/b); 4.66 (app d, JHH = 1.8 Hz,
H4a/b); 2.70 (m, 2H, dppe); 2.08 (m, 2H, dppe); 1.57 (s, 15H, Cp*).
13C{1H} NMR (CDCl3 400) δ/ppm: 140.9 (s, C5); 139.3−139.2 (m,
Ci, dppe); 139.0−138.9 (m, Ci, dppe); 137.5 (s, C6/7); 136.9 (s, C6/7);
135.4 (s, C8); 133.9−133.8 (m, Co, dppe); 133.4−133.3 (m, Co, dppe);
129.5 (m, C1); 129.0 (s, Cp, dppe); 127.6−127.4 (m, Cm, dppe); 126.6
(s, Cp, dppe); 126.5 (s, C2); 110.3 (s, C4); 109.4 (s, C3); 92.8 (s, Cp*);
29.7−29.3 (m, dppe); 10.26 (s, Me of Cp*). 31P{1H} NMR (CDCl3
400) δ/ppm: 81.77 (s, dppe). IR ATR/cm−1: 2057 ν(CC). ESI(+)-
MS m/z: calculated for [M]+([C46H46P2Ru + H]+) 763.2191, observed
763.2197 [M + H]+.
This compound was prepared from trans-[Ru{CCC(Me)(2-
C4H3S)}Cl(dppe)2]OTf ([1e]OTf, 0.40 g, 0.33 mmol) and t-BuOK
(0.040 g, 0.35 mmol) as described above. Workup gave 3e as a yellow-
1
brown powder (0.35 g, 0.281 mmol, 86%). H NMR (CDCl3 600
MHz) δ/ppm: 7.71 (m, 8H, Ho, dppe); 7.19−7.14 (m, 8H, Hp, dppe);
7.06 (m, 8H, Ho, dppe); 7.01−6.99 (m, 8H, Hm, dppe); 6.97 (m, 1H,
thienyl); 6.95−6.93 (m, 8H, Hm, dppe); 6.65 (m, 1H, thienyl); 6.40 (m,
Synthesis of [Ru{CCC(CH2)(4-MeS-C6H4)}(dppe)Cp*] (4d).
1H, thienyl), 5.22 (app d, JHH = 1.4 Hz, 1H, H4a/b); 4.51 (app d, JHH
=
1.4 Hz, 1H, H4a/b); 2.77 (m, 4H, dppe); 2.62 (m, 4H, dppe). 13C{1H}
NMR (CDCl3 600 MHz) δ/ppm: 146.7 (s, C5); 134.8 (m, Ci, dppe);
134.3 (m, Ci, dppe); 134.9 (m Co, dppe); 134.3 (m, Co, dppe); 129.3 (s,
thienyl); 129.2 (s, Cp, dppe); 128.6 (s, Cp, dppe); 127.5 (m, Cm, dppe);
126.9 (m, Cm, dppe); 124.4 (s, thienyl); 123.3 (s, thienyl); 113.5 (s,
C3); 111.3 (s, C4); 30.7 (m, dppe). 31P{1H} NMR (CDCl3 600 MHz)
δ/ppm: 49.73 (s, dppe). IR ATR/cm−1: 2041 ν(CC). APCI(+)-MS
m/z: calculated for [M]+ ([C60H53ClP4RuS − Cl + MeCN]+)
1072.2127, observed 1072.2189 [M − Cl + MeCN]+.
This compound was prepared from [Ru{CCC(Me)(4-MeS-
C6H4)}(dppe)Cp*]PF6 ([2d]OTf) (0.216 g, 0.226 mmol) and t-
BuOK (0.030 g, 0.27 mmol as described above. Workup gave 4d as an
1
orange-red solid (0.10 g, 0.12 mmol, 55%). H NMR (CDCl3 500
K
https://dx.doi.org/10.1021/acs.organomet.0c00371
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
MHz) δ/ppm: 7.72 (t, JHH = 8.4 Hz, 4H, Ho, dppe); 7.35−7.25 (m,
14H, Hm/p, dppe + H6/7); 7.19 (t, JHH = 8.2 Hz, 4H, Ho, dppe); 6.93 (d,
ν(BF4). ESI(+)-MS m/z: calculated for [M]+ ([C82H72ClP4RuS + H]+)
1350.3110, observed 1350.3413 [M + H]+.
Synthesis of [Ru{CCC(CH2CPh3)Ph}(dppe)Cp*]BF4 ([6b]BF4).
JHH = 8.5 Hz, 2H, H6/7); 5.21 (app d, JHH = 2.1 Hz, 1H, H4a/b); 4.62
(app d, JHH = 2.1 Hz, 1H, H4a/b); 2.67 (m, 2H, dppe); 2.45 (3H, SMe);
2.06 (2H, dppe); 1.57 (15H, Cp*). 13C{1H} NMR (CDCl3 500 MHz)
δ/ppm: 139.21 (m, Ci, dppe); 139.0 (m, Ci, dppe); 138.2 (s, C3); 137.3
(s, C5/8); 136.9 (s, C5/8); 133.9−133.8 (m, Co, dppe), 133.3 (m, Co,
dppe); 129.0 (s, Cp, dppe); 128.9 (s, Cp, dppe); 127.6−127.5 (m, Cm,
dppe); 127.1 (s, C6/7); 126.1 (s, C6/7); 109.8 (s, C2); 109.3 (s, C4); 92.8
(s, Cp*); 29.5 (m, dppe); 16.4 (s, SMe); 10.3 (s, Me of Cp*). 31P{1H}
NMR (CDCl3 500 MHz) δ/ppm: 81.1 (s, dppe). IR ATR/cm−1: 2055
ν(CC). ESI(+)-MS m/z: calculated for [M]+([C47H48P2Ru + H]+)
808.1995, observed 809.2080 [M + H]+.
General Procedure for Synthesis of Tritylium Adduct
Allenylidenes. A solution of [CPh3]BF4 in CH2Cl2 (5 mL) was
added to a solution of the appropriate alkenyl acetylide in CH2Cl2 (10
mL) and the mixture stirred for 1 h. Purification by preparative TLC
(hexane/acetone 7/3) gave the corresponding allenylidene in fair to
moderate yields.
This compound was prepared from [Ru{CCC(CH2)Ph}(dppe)-
Cp*] (4b) (0.099 g, 0.130 mmol) and [CPh3]BF4 (0.045 g, 0.136
mmol) as described above. Purification by preparative TLC gave
[6b]BF4 as a red-orange solid (0.038 g, 0.035 mmol, 27%). 1H NMR
(CDCl3 400 MHz) δ/ppm: 7.56−5.67 (m, 40H, dppe + Ph + CPh3);
4.10 (s, 2H, H4); 2.48 (m, 2H, dppe); 2.22 (m, 2H, dppe); 1.37 (s, 15H,
Cp*). 13C{1H} NMR (CDCl3 500 MHz) δ/ppm: 293.1 (m, C1); 201.9
(s, C2); 155.6 (s, C3); 147.0 (s, C5); 144.2 (s, Ph/CPh3); 137.1 (s, Ph/
CPh3); 133.1−133.0 (m, Co, dppe); 132.7 (s, Ph/CPh3); 132.6−132.5
(m, Co, dppe); 131.9 (s, Ph/CPh3); 131.5 (s, Ph/CPh3); 129.9 (s, Cp,
dppe); 129.4−129.3 (m, Cm, dppe); 128.8−128.7 (m, Cm, dppe); 128.5
(s, Ph/CPh3); 128.1 (s, Cp, dppe); 127.3 (s, Ph/CPh3); 126.3 (s, Ph/
CPh3); 103.2 (s, Cp*); 29.8 (s, C4); 28.1−27.8 (m, dppe); 10.0 (s, Me
of Cp*). 31P{1H} NMR (CDCl3 500 MHz) δ/ppm: 72.64 (s, dppe).
19F{1H} NMR (CDCl3 500 MHz) δ/ppm: −153.49 (s, BF4). IR ATR/
Synthesis of trans-[Ru{CCC(CH2CPh3)Ph}Cl(dppe)2]BF4
([5b]BF4).
cm−1: 1914 ν(CCC); 1054 ν(BF4). ESI(+)-MS m/z: calculated
for [M]+ ([C65H61P2Ru]+) 1005.3292, observed 1005.3276 [M]+.
Synthesis of [Ru{CCC(CH2CPh3)(4-MeS-C6H4)}(dppe)Cp*]BF4
([6d]BF4).
This compound was prepared from trans-[Ru{CCC(CH2)Ph}-
Cl(dppe)2] (3b) (0.105 g, 0.099 mmol) and [CPh3]BF4 (0.038 g, 0.11
mmol) as described above. Purification by preparative TLC (hexane/
acetone 7/3) gave [5b]BF4 as a red powder (0.042 g, 0.030 mmol,
31%). 1H NMR (CDCl3 400 MHz) δ/ppm: 7.67−6.95 (m, 60H, CPh3
+ C6H5 + Ph, dppe); 3.38 (s, 2H, H4); 3.12 (m, 4H, dppe); 2.62 (m, 4H,
dppe). 13C{1H} NMR (CDCl3 500 MHz) δ/ppm: 219.1 (s, C2); 165.5
(s, C3); 145.6 (s, C5); 133.9−126.8 (CPh3 + Ph + dppe); 54.3 (s, C4);
(C1 not observed). 31P{1H} NMR (CDCl3 400 MHz) δ/ppm: 44.83 (s,
dppe). 19F{1H} NMR (CDCl3 500 MHz) δ/ppm: −152.23 (s, BF4). IR
ATR/cm−1: 1904 ν(CCC); 1049 ν(BF4). ESI(+)-MS m/z:
calculated for [M]+ ([C81H70ClP4Ru]+) 1303.3160, observed
1303.3163 [M]+.
This compound was prepared from [Ru{CCC(CH2)(4-MeS-
C6H4)}(dppe)Cp*] (4d) (0.109 g, 0.135 mmol) and [CPh3]BF4
(0.045 g, 0.136 mmol) as described above. Workup gave [6d]BF4 as
a black-purple solid (0.055 g, 0.048 mmol, 36%). 1H NMR (CDCl3 600
Synthesis of trans-[Ru{CCC(CH2CPh3)(4-MeS-C6H4)}Cl-
(dppe)2]BF4 ([5d]BF4).
MHz) δ/ppm: 7.56−6.83 (m, 35H, dppe + CPh3); 6.78 (app d, JHH
=
8.3 Hz, 2H, H6/7); 6.42 (app d, JHH = 8.3 Hz, 2H, H6/7); 2.42 (s, 2H,
H4); 2.26 (m, 2H, dppe); 2.15 (m, 2H, dppe); 1.62 (s, 3H, SMe); 1.41
(s, 15H, Cp*). 13C{1H} NMR (CDCl3 600 MHz) δ/ppm: 197.3 (s,
C2); 147.04 (s, C3); 133.1−126.7 (dppe + CPh3); 127.7 (s, C6/7); 126.4
(s, C6/7); 13.2 (s, Cp*); 29.8 (m, dppe); 15.6 (s, C4); 10.1 (s, Me of
Cp*); 10.0 (s, SMe); (C1 not observed). 31P{1H} NMR (CDCl3 600
MHz) δ/ppm: 72.69 (s, dppe). 19F{1H} NMR (CDCl3 600 MHz) δ/
ppm: −153.99 (s, BF4). IR ATR/cm−1: 1917 ν(CCC); 1062
ν(BF4). ESI(+)-MS m/z: calculated for [M]+ ([C66H63P2RuS]+)
1051.3169, observed 1051.3199 [M]+.
This compound was prepared from trans-[Ru{CCC(CH2)(4-
MeS-C6H4)}Cl(dppe)2] (3d) (0.103 g, 0.093 mmol) and [CPh3]BF4
(0.040 g, 0.12 mmol) as described above. Workup gave [5d]BF4 as a
black-purple solid (0.050 g, 0.035 mmol, 37%). 1H NMR (CDCl3 400
Synthesis of trans-[Ru{CCC(CHCPh3)Me}Cl(dppe)2] (7a).
MHz) δ/ppm: 7.43−6.80 (m, 55H, dppe + CPh3); 6.53 (app d, JHH
=
8.7 Hz, 2H, H6/7); 6.37 (app d, JHH = 8.7 Hz, 2H, H6/7); 3.25 (s, 2H,
C4); 2.90 (m, 4H, dppe); 2.54 (m, 4H, dppe); 2.40 (s, 3H, SMe).
13C{1H} NMR (CDCl3 400 MHz) δ/ppm: 301.04 (m, C1); 235.0 (s,
C2); 134.2 (s, C3); 145.7 (s, C5); 133.7−133.5 (2m, 2 × Co, dppe);
133.3 (m, Ci, dppe); 132.8 (m, Ci, dppe); 131.5 (s, CPh3); 131.1 (s,
CPh3); 130.3 (s, CPh3); 129.6 (s, Cp, dppe); 129.1 (s, C6/7); 128.9 (m,
Cm, dppe); 128.3 (s, Cp, dppe); 127.8 (m, Cm, dppe); 126.8 (s, CPh3);
124.8 (s, C6/7); 52.0 (s, C4); 29.4 (m, dppe). 31P{1H} NMR (CDCl3
400 MHz) δ/ppm: 42.42 (s, dppe). 19F{1H} NMR (CDCl3 500 MHz)
δ/ppm: −150.98 (s, BF4). IR ATR/cm−1: 1904 ν(CCC); 1056
A solution of [CPh3]BF4 (0.036 g, 0.109 mmol) in CH2Cl2 (5 mL) was
added to a solution of trans-[Ru{CCC(CH2)Me}Cl(dppe)2]
(3a) (0.103 g, 0.103 mmol) in CH2Cl2 (5 mL) and the mixture stirred
for 1 h. The solvent was removed and the residue dissolved in minimal
CH2Cl2 and precipitated by rapid addition to rapidly stirred Et2O (20
mL), giving a brown powder, presumably trans-[Ru{CCC-
(CH2CPh3)Me}Cl(dppe)2]BF4 (0.120 g). Efforts to purity this crude
material failed, and instead the powder was reacted onward by charging
with THF (20 mL) and adding t-BuOK (0.015 g, 0.134 mmol) and the
solution was stirred for 2 h. The solvent was then removed and the
L
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residue purified by passage through a basic alumina column, from which
a yellow powder was obtained (0.089 g). Single crystals suitable for X-
ray diffraction were grown by layering a CH2Cl2 solution of the crude
material with MeOH, giving 7a as a yellow crystalline material (0.07 g,
0.06 mmol, 60%). 1H NMR (CDCl3 500 MHz) δ/ppm: 7.60 (m, 8H,
Ho, dppe); 7.28−7.25 (m, 16H, CPh3 + Hp, dppe); 7.22−7.10 (m, 20H,
CPh3 + Hm + Ho, dppe); 6.97−6.92 (m, 16H, CPh3 + Hm, dppe); 5.82
(app d, JHH = 0.8 Hz, 1H, H4); 2.70 (m, 4H, dppe); 2.59 (m, 4H, dppe);
0.82 (s, 3H, H5). 13C{1H} NMR (CDCl3 500 MHz) δ/ppm: 148.6 (s,
C6); 136.8 (s, C4); 135.7 (m, Ci, dppe); 134.7 (m, Co, dppe); 134.4 (m,
Co, dppe); 130.4 (s, CPh3); 129.0 (s, Cp, dppe); 128.7 (s, Cp, dppe);
127.6 (s, CPH3); 127.2 (m, Cm, dppe); 127.0 (m, Cm, dppe); 125.7 (s,
C2); 117.9 (s, C3); 30.8 (m, dppe); 21.4 (s, C5). 31P{1H} NMR (CDCl3
500 MHz) δ/ppm: 49.57 (s, dppe). IR ATR/cm−1: 2062 ν(CC).
ESI(+)-MS m/z: calculated for [M]+ ([C76H67ClP4Ru + H]+)
1241.2998, observed 1241.3040 [M + H]+.
General Procedure for Synthesis of Styrene-Functionalized
Allenylidenes. A solution of [C7H7]BF4 in MeCN (5 mL) was added
to a solution of the appropriate alkenyl acetylide in CH2Cl2 (10 mL)
and stirred for 1 h. The solvent was removed, and the residue was
triturated with Et2O and collected by vacuum filtration. The solid was
then dissolved in CHCl3 (20 mL) and stirred for 2 h at 40 °C in a flask
open to the atmosphere. Purification by preparative TLC (hexane/
acetone 7/3) gave the resulting product in fair to moderate yields.
Synthesis of trans-[Ru{CCC(CHCHPh)Ph}Cl(dppe)2]BF4
([10b]BF4).
Synthesis of trans-[Ru{CCC(CHCHPh)(4-MeS-C6H4)}Cl-
(dppe)2]BF4 ([10d]BF4).
This compound was prepared from trans-[Ru{CCC(CH2)(4-
MeS-C6H4)}Cl(dppe)2] (3d) (0.080 g, 0.072 mmol) and [C7H7]BF4
(0.015 g, 0.084 mmol) as described above, giving an impure purple
powder. Stirring the crude material in CHCl3 at 40 °C in a flask open to
the atmosphere gave a deep purple solution, which was purified by
preparative TLC (hexane/acetone 7/3) to give [8d]BF4 as a purple
powder (0.045 g, 0.035 mmol, 49%). 1H NMR (CDCl3 500 MHz) δ/
ppm: 7.51−6.91 (m, 49H, Ph + H6/7, dppe); 6.89 (app d, JHH = 15.6 Hz,
1H, H4/9); 6.54 (app d, JHH = 15.6 Hz, 1H, H4/9); 3.08 (m, 4H, dppe);
2.81 (m, 4H, dppe); 2.57 (s, 3H, SMe). 13C{1H} NMR (CDCl3 500
MHz) δ/ppm: 286.2 (m, C1); 203.6 (s, C2); 155.5 (s, C3); 146.8 (s,
Ph); 146.2 (s, Ph); 140.4 (s, Ph); 135.7 (s, Ph); 134.5 (m, Ci, dppe);
133.7 (m, Co, dppe); 133.4 (m, Co, dppe); 131.9 (s, Ph); 131.7 (s, Ph);
131.2 (s, Cp, dppe); 130.4 (s, Cp, dppe); 129.6 (s, Ph); 129.0 (s, Ph);
128.8 (s, Ph); 128.8 (m, Cm, dppe); 127.9 (m, Cm, dppe); 125.7 (s, Ph);
28.7−28.3 (m, dppe); 14.9 (s, SMe). 31P{1H} NMR (CDCl3 500 MHz)
δ/ppm: 39.78 (s, dppe). 31P{1H} NMR (CDCl3 500 MHz) δ/ppm:
39.78 (s, dppe). 19F{1H} NMR (CDCl3 500 MHz) δ/ppm: −151.64 (s,
BF4). IR ATR/cm−1: 1923 ν(CCC); 1054 ν(BF4). APCI(+)-MS
m/z: calculated for [M]+ ([C70H62ClP4RuS]+) 1195.2255, observed
1195.2278 [M]+.
Synthesis of [Ru{CCC(CHCHPh)Ph}(dppe)Cp*]BF4
([11b]BF4).
This compound was prepared from trans-[Ru{CCC(CH2)Ph}-
Cl(dppe)2] (3b) (0.095 g, 0.090 mmol) and [C7H7]BF4 (0.016 g, 0.090
mmol) as described above, giving an impure red powder. After the
powder was stirred in CHCl3 under a laboratory atmosphere, the
resulting deep purple solution was purified by preparative TLC
(hexane/acetone 7/3) to give [10b]BF4 as a purple powder (0.040 g,
0.032 mmol, 36%). Single crystals suitable for X-ray diffraction were
This compound was prepared from [Ru{CCC(CH2)Ph}(dppe)-
Cp*] (4b) (0.103 g, 0.135 mmol) and [C7H7]BF4 (0.025 g, 0.140
mmol) as described above, giving an impure red powder. The crude
material was stirred in CHCl3 at 40 °C to give a deep purple solution,
which was purified by preparative TLC (hexane/acetone 7/3) to afford
[9b]BF4 as a red-purple powder (0.035 g, 0.037 mmol, 28%). 1H NMR
(CDCl3 500 MHz) δ/ppm: 7.56−7.07 (m, 32H, dppe + Ph+ HC
CH); 2.86 (m, 2H, dppe); 2.59 (m, 2H, dppe); 1.64 (s, 15H, Cp*).
13C{1H} NMR (CDCl3 500 MHz) δ/ppm: 285.5 (m, C1); 203.1 (s,
C2); 143.3 (s, C3); 142.4 (s, Ph); 136.3 (s, Ph); 132.7−132.6 (m, Co,
dppe); 132.3−132.2 (m, Co, dppe); 137.8 (s, Ph); 131.4 (s, Ph); 131.3
(s, Ph); 129.7 (s, Cp, dppe); 129.2 (s, Cp, dppe); 128.8−128.7 (m, Cm,
dppe); 128.6−128.5 (m, Cm, dppe); 127.9 (s, Ph); 127.4 (s, Ph); 102.3
(s, Cp*); 30.5 (m, dppe); 10.12 (s, Me of Cp*). 31P{1H} NMR (CDCl3
500 MHz) δ/ppm: 79.26 (s, dppe). 19F{1H} NMR (CDCl3 500 MHz)
δ/ppm: −154.15 (s, BF4). IR ATR/cm−1: 1927 ν(CCC); 1057
ν(BF4). ESI(+)-MS m/z: calculated for [M]+ ([C53H51P2Ru]+)
851.2509, observed 851.2548 [M]+.
1
grown by layering a CH2Cl2 solution of [10b]BF4 with hexane. H
NMR (CDCl3 500 MHz) δ/ppm: 7.68 (t, JHH = 7.4 Hz, 1H, Ph); 7.53
(t, JHH = 7.4 Hz, 1H, Ph); 7.35 (m, 4H, Ph); 7.30−7.24 (m, 4H, Ph);
7.18 (t, JHH = 7.7 Hz, 8H, Ho, dppe); 7.08 (m, 16H, Ho, + Hp, dppe);
7.03 (t, JHH = 7.6 Hz, 8H, Hm, dppe); 6.95 (t, JHH = 7.6 Hz, 8H, Hm,
dppe); 6.71 (d, JHH = 13.0 Hz, 1H, H4/9); 6.58 (d, JHH = 13.0 Hz, 1H,
H
4/9); 3.08 (m, 4H, dppe); 2.85 (m, 4H, dppe). 13C{1H} NMR (CDCl3
500 MHz) δ/ppm: 294.3 (m, C1); 211.5 (s, C2); 157.4 (s, C3); 146.0 (s,
C4); 144.0 (s, C4/9); 135.8 (s, C4/9); 133.8 (m, Co, dppe); 133.4 (m, Co,
dppe); 132.7 (s, C5); 132.6 (s, Ph); 131.2 (s, Ph); 130.4 (s, Ph); 129.7
(s, Ph); 129.0 (s, Ph); 128.7 (m, Cm, dppe); 128.5 (s, Ph); 128.0 (m,
Cm, dppe); 28.6−28.4 (m, dppe). 31P{1H} NMR (CDCl3 500 MHz) δ/
ppm: 39.48 (s, dppe). 19F{1H} NMR (CDCl3 500 MHz) δ/ppm:
−153.86 (s, BF4). IR ATR/cm−1: 1921 ν(CCC); 1026 ν(BF4).
APCI(+)-MS m/z: calculated for [M]+ ([C69H60ClP4Ru]+) 1149.2378,
observed 1149.2386 [M]+.
M
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Synthesis of [Ru{CCC(CHCHPh)(4-MeS-C6H4)}(dppe)Cp*]-
BF4 ([11d]BF4).
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
M.R.H. holds a Dean’s Excellence in Science Ph.D. Scholarship
from the Faculty of Science, University of Western Australia.
The Forrest Research Foundation is sincerely thanked for the
award of a Forrest Fellowship to M.K. The authors gratefully
acknowledge the facilities and the scientific and technical
assistance of Microscopy Australian at the Centre for
Microscopy, Characterisation Analysis, The University of
Western Australia, a facility funded by the University, State,
and Commonwealth Governments.
This compound was prepared from [Ru{CCC(CH2)(4-MeS-
C6H4)(dppe)Cp*] (4d) (0.111 g, 0.137 mmol) and [C7H7]BF4 (0.030
g, 0.169 mmol) as described above, giving an impure red powder.
Stirring the crude compound in CHCl3 at 40 °C in a flask open to the
atmosphere gave a deep purple solution, which was purified by
preparative TLC (hexane/acetone 7/3) to give [9d]BF4 as a purple
powder (0.045 g, 0.046 mmol, 33%). 1H NMR (CDCl3 400 MHz) δ/
ppm: 7.67−7.14 (m, 31H, H6 + H7 + HCCH + Ph, dppe); 2.50 (m,
2H, dppe); 2.16 (m, 2H, dppe); 1.60 (2, 15H, Cp*); 1.42 (s, 3H, SMe).
13C{1H} NMR (CDCl3 400 MHz) δ/ppm: 285.7 (m, C1); 202.9 (s,
C2); 132.9 (s, C3); 132.5−128.7 (m, Ph + dppe + C4 + C6 + C7 + C9);
99.7 (s, Cp*); 30.1−29.6 (m, dppe); 9.87 (s, SMe); 9.11 (s, Me of
Cp*). 31P{1H} NMR (CDCl3 400 MHz) δ/ppm: 71.54 (s, dppe).
19F{1H} NMR (CDCl3 500 MHz) δ/ppm: −152.06 (s, BF4). IR ATR/
cm−1: 1930 ν(CCC); 1059 ν(BF4). ESI(+)-MS m/z: calculated
for [M]+ ([C54H53P2RuS]+) 897.2387, observed 896.2388 [M]+.
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ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.organomet.0c00371.
1
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AUTHOR INFORMATION
■
Corresponding Author
Paul J. Low − School of Molecular Sciences, University of Western
Australia, Crawley 6009, Western Australia, Australia;
orcid.org/0000-0003-1136-2296; Email: paul.low@
uwa.edu.ua
Authors
Michael R. Hall − School of Molecular Sciences, University of
Western Australia, Crawley 6009, Western Australia, Australia;
orcid.org/0000-0002-3179-5382
Marcus Korb − School of Molecular Sciences, University of
Western Australia, Crawley 6009, Western Australia, Australia
Stephen A. Moggach − School of Molecular Sciences, University
of Western Australia, Crawley 6009, Western Australia,
Australia
Complete contact information is available at:
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