Functionally Altered Ruthenaindenes with Electron-Rich and Electron-Poor Substituents

Article abstract of DOI:10.1021/acs.organomet.9b00788

A series of ruthenaindene complexes containing electron-donating and-withdrawing groups were synthesized and characterized. The ruthenaindenes were synthesized from ruthenium butenynyl complexes which were formed by the treatment of Me₂Ru(PMe₃)₄ with 1,4-diaryl-1,3-butadiynes in methanol. Electrochemistry of the metal center in ruthenaindenes showed that the complexes with electron-donating groups on the aromatic ring have significantly lower oxidation potentials in comparison to complexes with electron-withdrawing groups. Even though the substitution of the aromatic ring with electron-donating/-withdrawing groups is remote from the metal center, the electronic properties of the substituents are relayed effectively to the metal center, indicating that the metal center in the ruthenaindenes is quite intimately embedded into the organic aromatic framework.

Full text of DOI:10.1021/acs.organomet.9b00788

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Article
Functionally Altered Ruthenaindenes with Electron-Rich and
Electron-Poor Substituents
Hsiu L. Li, Synøve Ø. Scottwell, James D. Watson, Timothy E. Elton, Hon C. Yu, Mohan Bhadbhade,
and Leslie D. Field*
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ABSTRACT: A series of ruthenaindene complexes containing
electron-donating and -withdrawing groups were synthesized and
characterized. The ruthenaindenes were synthesized from
ruthenium butenynyl complexes which were formed by the
treatment of Me2Ru(PMe3)4 with 1,4-diaryl-1,3-butadiynes in
methanol. Electrochemistry of the metal center in ruthenaindenes
showed that the complexes with electron-donating groups on the
aromatic ring have significantly lower oxidation potentials in
comparison to complexes with electron-withdrawing groups. Even
though the substitution of the aromatic ring with electron-
donating/-withdrawing groups is remote from the metal center, the
electronic properties of the substituents are relayed effectively to the metal center, indicating that the metal center in the
ruthenaindenes is quite intimately embedded into the organic aromatic framework.
Scheme 1. Synthesis of Ruthenaindenes
INTRODUCTION
■
The indene ring system has a benzene ring fused to a
cyclopentene ring. Ruthenaindenes are cyclometalated ruthe-
nium complexes where the ruthenium metal replaces one of
the carbon atoms in the five-membered ring of an indene
molecule. Ruthenaindenes are a subset of ruthenacyclopenta-
dienes that have very few occurrences in the literature.1
Despite the relative rarity of ruthenaindene-type complexes,
there are examples of metalloindenes among the early
transition metals such as titanium,2 vanadium,3 zirconium,4
and tantalum,5 as well as late transition metals including
rhodium,6 osmium,7 and iridium.8
Our interest in ruthenaindenes stems from an earlier
discovery where the treatment of ruthenium butenynyl
complexes [Ru(η3-RC6H4CCCCR′(C6H4R))(PMe3)4]+
donating and electron-withdrawing substituents attached to the
aryl rings.
t
(R = Bu, H, Me; R′ = H, Me) with dimethylmagnesium
afforded ruthenaindenes [Ru(RC6H4CCCCR′(C6H3R)-
(PMe3)4] (Scheme 1).9 The reaction involves decoordination
of the alkyne fragment, isomerization of the metal-substituted
alkene, and then ortho metalation of the aromatic ring attached
to the vinylic group with concomitant loss of the ortho proton.
The ruthenaindenes are remarkably stable and, as the Ru
metal is σ-bonded directly to the rigid aromatic framework,
better overlap of the metal orbitals with the organic framework
would suggest better electronic communication across the
extended metalloaromatic network. In this paper, we probe the
effect of changing the electronic properties of the organic
framework on the properties of the metal center through the
synthesis of a series of ruthenaindenes with remote electron-
RESULTS AND DISCUSSION
■
Synthesis of Ruthenium Butenynyl Complexes. The
most direct route to metal butenynyl complexes is by reaction
of a metal hydride with a 1,4-diaryl- or 1,4-dialkyl-1,3-
butadiyne.10 For example, the iron butenynyl complex
[Fe(η3-PhCCCCHPh)(dmpe)2]+ has been synthesized
Received: November 18, 2019
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by treatment of [FeH2(dmpe)2] with 1,4-diphenyl-1,3-
butadiyne in an alcohol solution.11
While treatment of [RuH2(PMe3)4] with 1,4-bis(4-methox-
yphenyl)-1,3-butadiyne does form the desired butenynyl
complex 1a, the reaction does not go to completion and
hydrogenated butadiyne products were also formed in the
reaction, including 4-MeOC6H4CHCHCH2CH2C6H4-4-
OMe.12
The formation of hydrogenated butadiyne products was
minimized by using the dimethyl complex [RuMe2(PMe3)4] as
the metal precursor. Treatment of [RuMe2(PMe3)4] with
diarylbutadiynes and sodium tetraphenylborate in methanol
solution afforded the butenynyl complexes 1a−c as tetraphe-
nylborate salts (Scheme 2). A small amount of [RuH-
(PMe3)5]+ was also isolated as a byproduct.13 While we have
not investigated the mechanism of this reaction in detail, the
methanol solvent plays an important role and the reaction
probably proceeds by protodemethylation of the dimethyl
ruthenium complex to form a methoxy methyl complex where
β-hydride elimination produces “slow release” of a metal
hydride in situ.14 Reaction of the butadiyne with the metal
hydride followed by a further protodemethylation reaction
would give the desired butenynyl complex.
Figure 1. ORTEP plot of [Ru(η3-CF3-4-C6H4CCCCH(C6H4-4-
−
CF3))(PMe3)4]+BF4 (1c) at 50% ellipsoid probability. Hydrogen
atoms and the BF4− counterion have been omitted for clarity. Selected
bond lengths (Å) and angles (deg): Ru1−P1 2.390(4), Ru1−P2
2.302(4), Ru1−P3 2.392(4), Ru1−P4 2.384(4), Ru1−C8a 2.350(12),
Ru1−C9a 2.215(14), Ru1−C10a 2.155(16), C8a−C9a 1.24(2),
C9a−C10a 1.44(2), C10a−C11a 1.32(2), C9a−Ru1−C8a 31.2(5),
C10a−Ru1−C8a 69.6(5), C10a−Ru1−C9a 38.3(5), C9a−C8a−C5a
142.6(13), C8a−C9a−C10a 149.0(15), C11a−C10a−C9a 135.6(15),
C10a−C11a−C2a 127.7(14).
Scheme 2. Synthesis of Ruthenium Butenynes
(C6H4-4-Me))(P(OEt)2Ph)4]+, and [Ru(η3-PhCCC
CHPh)(dppm)2]+.18
Synthesis of Ruthenaindenes. Treatment of butenynyl
−
complexes containing BPh4 counterions 1a−c (BPh4) with
halide-free dimethylmagnesium afforded the expected ruth-
enaindene complexes 2a−c (Scheme 3) in moderate yields.
The quality of the dimethylmagnesium reagent was crucial in
this reaction, as the presence of halide impurities always
afforded unwanted halide-containing byproducts. Use of other
bases such as sodium amide and methyllithium did not give the
desired ruthenaindenes.
The butenynyl complexes 1a−c can also be synthesized as
tetrafluoroborate salts by protonation of the bis(acetylide)
complexes cis-[Ru(CCAr)2(PMe3)4] with a mild acid such
as 2,6-lutidinium tetrafluoroborate (vide infra).
Scheme 3. Synthesis of Functionalized Ruthenaindenes
31P{1H} NMR spectra of each of the butenynyl complexes
1a−c exhibit three sharp signals: two sets of doublets of triplets
integrating to 1P each, corresponding to the two inequivalent
equatorial phosphines, and a triplet integrating to 2P for the
two equivalent axial phosphines, similar to spectra reported for
analogous complexes in the literature.15 In addition, a
phosphorus-coupled doublet is observed for the vinylic proton
in the region 7.0−7.6 ppm in the 1H NMR spectra, as
previously reported for analogous butenynyl complexes.16 13C
NMR resonances of the alkene carbons RuCC and CCH
were assigned with the aid of 2D NMR experiments in the
ranges 144−155 and 128−131 ppm, respectively. 13C NMR
resonances for alkyne carbons ArCC and ArCC were
found in the ranges 113−118 and 57−66 ppm, respectively.17
Crystals of the butenynyl complex 1c, suitable for X-ray
crystallography, were grown from an acetone solution layered
with pentane, and the structure is shown in Figure 1. Ru−C
and C−C bond lengths as well as the C−C−C bond angle
follow trends similar to the analogous bond lengths and angles
for related Ru−butenyne complexes that have previously been
characterized crystallographically: [Ru(η3-PhCCC
CHPh)(PMe2Ph)4]+, [Ru(η3-Me-4-C6H4CCCCH-
The 31P{1H} NMR spectra of the ruthenaindene complexes
2a−c exhibit a triplet integrating to 2P and two sets of
doublets of triplets integrating to 1P, each being similar to
those for previously reported ruthenaindene complexes.9 The
CCH proton in the five-membered ring was observed as a
phosphorus-coupled multiplet in the 7.5−8.3 ppm region of
the 1H NMR spectrum. The alkene and alkyne carbons appear
in the 151−162 and 92−112 ppm regions of the 13C NMR
B
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spectra, respectively. The aromatic carbon directly bonded to
ruthenium appears near 184 ppm for both 2a and 2c, similarly
to those previously reported (181−182 ppm).9
An X-ray crystal structure of 2a is shown in Figure 2 and has
structural parameters similar to those of the previously
reported ruthenaindenes [Ru(tBu-4-C6H4CCCCH-
(C6H3-4-tBu)(PMe3)4] and [Ru(PhCCCCH(C6H4)-
(PMe3)4].9
mixture exhibited pairs of triplets for the cis isomers and
singlets for the trans isomers, as previously reported for
analogous complexes.19 Using this synthetic approach, the cis
isomers were generally the major isomer formed in the
mixture.
Crystals of cis-3c, suitable for X-ray crystallography, were
grown from a cooled solution of the complex in toluene
(Figure 3). There was some orientational disorder about one
Figure 2. ORTEP plot of [Ru(MeO-4-C6H4CCCCH(C6H3-4-
OMe)(PMe3)4] (2a) at 50% ellipsoid probability. Hydrogen atoms
have been omitted for clarity. Selected bond lengths (Å) and angles
(deg): Ru1−C6 2.135(2), Ru1−C9 2.156(3), Ru1−P4 2.3409(7),
Ru1−P1 2.3531(7), Ru1−P2 2.3573(7), Ru1−P3 2.3631(7), C5−C6
1.430(3), C5−C8 1.440(4), C8−C9 1.361(4), C9−C10 1.423(4),
C10−C11 1.211(4), C6−Ru1−C9 78.24(10), C6−C5−C8 115.6(2),
C5−C6−Ru1 113.47(17), C9−C8−C5 118.3(2), C8−C9−C10
116.9(2), C8−C9−Ru1 114.04(19), C10−C9−Ru1 128.84(19),
C9−C10−C11 177.5(3).
Figure 3. ORTEP plot of cis-[Ru(CCC6H4-4-CF3)2(PMe3)4] (3c)
at 50% ellipsoid probability. Hydrogen atoms have been omitted for
clarity. Selected bond lengths (Å) and angles (deg): Ru1−P1
2.3555(18), Ru1−P2 2.3654(19), Ru1−P3 2.3511(19), Ru1−P4
2.3669(17), Ru1−C1a 2.048(6), Ru1−C1b 2.024(6), C1a−C2a
1.201(8), C1b−C2b 1.231(8), C2a-C3a 1.424(9), C2b−C3b
1.435(8), C1b−Ru1−C1a 88.6(2), C2a−C1a−Ru1 175.7(6), C1a−
C2a−C3a 175.7(7), C2b−C1b−Ru1 176.8(6), C1b−C2b−C3b
175.6(7).
Synthesis of Ruthenium Butenynyl and Vinylidene
Complexes from Ruthenium Bis(acetylides). We have
previously reported the formation of iron and ruthenium
butenynyl complexes by the coupling of the acetylide ligands in
metal bis(acetylides) in the presence of an acid.11,15
Mechanistically, it has been proposed that one of the metal-
bound acetylides protonates at the β-carbon to produce a
metal vinylidene and the butenyne ligand is formed by
migration of the second acetylide to the α-carbon with π-
coordination of the pendant CC.
of the PMe3 groups and both the CF3 groups; however, the
Ru−C and CC bond lengths for complex 3c are comparable
with those for the analogous cis-disposed Ru bis(acetylide)
complexes [Ru(CCC6H4-4-OMe)2(PMe3)4] and [Ru(C
CPh)2(P(CH2CH2PPh2)3)].19,20
The Ru bis(arylacetylido) complexes 3a−c were generally
obtained as a mixtures of cis and trans isomers; however, there
is only very slow interconversion of the isomers of 3b at room
temperature.19 Irradiation of a cis/trans mixture of 3b with a
UV light source converts the mixture exclusively to the trans
isomer.19
Ru bis(arylacetylido) complexes 3a−c were synthesized by
the σ-bond metathesis reaction of [RuMe2(PMe3)4] with a
series of arylacetylenes (Scheme 4). In general, the bis-
(acetylide) complexes were isolated as mixtures of cis and trans
isomers, with the relative amounts of isomers varying from
batch to batch. The 31P{1H} NMR spectra of the product
Protonation of the trans isomer of 3b with lutidinium
afforded pink crystals of the trans-vinylidene complex [Ru(
CCH(Ph))(CCPh)(PMe3)4]+ (4b) (Scheme 5 and
Scheme 5. Protonation of trans-Bis(acetylide) Complexes
Scheme 4. Synthesis of Ruthenium Bis(acetylides)
C
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Figure 4). The crystal structure of 4b revealed bond lengths
and angles similar to those reported for the vinylidene complex
isomers (not observed) rapidly rearrange with C−C coupling
to give the butenynyl complexes 1a−c (Scheme 6). The
butenynyl complexes can be isolated from the product mixture
by crystallization.
The fact that the trans-vinylidenes are stable suggests that it
is only the isomers of the ruthenium bisacetylides with the cis
stereochemistry which protonate and rearrange to form
butenynyl complexes.
Electrochemistry. The cyclic voltammograms (CVs) of
the ruthenium butenynyl complexes 1a−c exhibit a single
reversible one-electron process between 0.50 and 0.82 V,
indicative of a Ru2+/Ru3+ couple (Figure 5 and Table 1). The
Figure 4. ORTEP plot of trans-[Ru(CCH(Ph))(CCPh)-
−
(PMe3)4]+BF4 (4b) at 50% ellipsoid probability. Hydrogen atoms,
−
pentane solvate (partially occupied), and the BF4 counterion have
been omitted for clarity. Selected bond lengths (Å) and angles (deg):
Ru1−P1 2.3754(14), Ru1−P2 2.3655(15), Ru1−P3 2.3721(15),
Ru1−P4 2.4055(16), Ru1−C8a 1.873(5), Ru1−C8b 2.083(5), C7a−
C8a 1.336(8), C7b−C8b 1.197(8), C6a−C7a 1.480(8), C7a−C8a−
Ru1 172.2(5), C7b−C8b−Ru1 178.2(5), C8a−C7a−C6a 127.6(6).
[Ru(CCMe(Ph))(CCPh)(P(OEt)3)4]+.21 The pentet
at 5.36 ppm in the 1H NMR spectrum and the pentet at 355.3
ppm in the 13C NMR spectrum are characteristic for a
vinylidene moiety, as reported in the literature for analogous
Ru complexes (1H 3.8−6.0 ppm, 13C 351−380 ppm).15,21
Crystals of the vinylidene complex [Ru(CCH(C6H4-4-
OMe))(CCC6H4-4-OMe)(PMe3)4]+ (4a) were also iso-
lated by treatment of the bis(acetylide) complex 3a containing
about 30% trans isomer with lutidinium tetrafluoroborate. The
X-ray crystal structure including the core bond lengths and
bond angles and NMR parameters are available in the
Supporting Information.
The trans-vinylidene complexes 4a,b are stable, and the
vinylidene and acetylide groups do not rearrange and couple to
form the butenynyl complexes even on heating. However,
treatment of the bis(acetylide) complexes 3a−c (as mixtures of
cis and trans isomers) with a mild acid (2,6-lutidinium
tetrafluoroborate) presumably protonates at the β-carbon to
form the cationic vinylidene species, but the protonated cis
Figure 5. Cyclic voltammogram traces for butenynyl complexes
[Ru(η3-R-4-C6H4CCCCH(C6H4-4-R))(PMe3)4]+BF4− (1a (R =
OMe); 1b (R = H); 1c (R = CF3)) acquired in 0.1 M NBu4PF6 in
CH2Cl2. Scan rate: 100 mV/s. The asterisk denotes oxidation of the
−
BPh4 counterion.
Table 1. Electrochemical Data for Butenynyl and
Ruthenaindene Complexes
a
complex
−R
E
1/2/V
1a
1b
1c
2a
2b
2c
−OMe
−H
−CF3
−OMe
−H
0.50
0.74
0.82
−0.40
−0.30
−0.06
−CF3
a
E1/2 potential referenced to Fc/Fc+. Conditions for CV: in CH2Cl2,
0.1 M NBu4PF6, scan rate 100 mV/s, glassy-carbon working electrode,
Pt/Ti auxiliary electrode, Ag/Ag+ quasi-reference electrode.
Scheme 6. Protonation and Rearrangement of cis-
Bis(acetylide) Complexes
−
trace for complex 1a (which was isolated as its BPh4 salt)
shows an additional irreversible process at 0.38 V, which we
ascribe to oxidation of the tetraphenylborate counterion.22
The relatively high oxidation potential of the butenynyl
complexes is consistent with the positive charge on these metal
complexes and the presence of a weakly bound π-acetylene
donor in the ligand set.
The oxidation potential for the complex where the aromatic
rings bear electron-withdrawing −CF3 substituents (complex
1c) is higher than those for the other two butenynyl
complexes. Conversely, the Ru2+ center in complex 1a,
where the aromatic rings have electron-donating − OMe
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substituents, is the most easily oxidized complex of the series of
butenynyl complexes.
The CVs of the ruthenaindene complexes 2a−c exhibited a
reversible one-electron process ascribed to a Ru2+/Ru3+ couple
between −0.40 and −0.06 V (Figure 6 and Table 1).
center, they have a significant influence on the oxidation
potential of the metal. With an electron-donating substituent
(−OMe) on the aromatic ring, the potential of the Ru2+/Ru3+
couple (−0.40 V) is substantially lower than that for the
complex with an electron-withdrawing (−CF3) substituent
(−0.06 V). Even though the substitution of the aromatic ring
with electron-donating/-withdrawing groups is distant from
the metal center, the electronic properties of the substituents
are relayed effectively to the metal center, in line with the
notion that metal center in the ruthenaindenes is quite
intimately embedded into the organic aromatic framework.
Electron-donor substituents that render the aromatic system
more electron rich make the Ru center easier to oxidize.
Conversely, electron-withdrawing substituents attached to the
aromatic ring pull electron density away from the Ru center
and make it more difficult to oxidize. There is obvious scope to
moderate the electronic characteristics of the metal center over
a significant range by tuning the substituents on the aromatic
rings.
EXPERIMENTAL SECTION
■
General Procedures. All syntheses and manipulations involving
air-sensitive compounds were carried out using standard Schlenk
techniques or in nitrogen- or argon-filled glove boxes. Solvents were
dried and distilled under nitrogen from sodium/benzophenone
(benzene, toluene, tetrahydrofuran) or boric anhydride (acetone).
Diethyl ether and pentane were dried and deoxygenated using a Pure
Solv 400-4-MD (Innovative Technology) solvent purification system.
Deuterated solvents were dried and distilled under vacuum from
sodium/benzophenone (benzene-d6, tetrahydrofuran-d8) and boric
anhydride (acetone-d6). NMR spectra were recorded on Bruker
Avance 400 and 600 NMR spectrometers at 298 K unless otherwise
Figure 6. Cyclic voltammogram traces for ruthenaindene complexes
[Ru(R-4-C6H4CCCCH(C6H3-4-R)(PMe3)4] (2a (R = OMe);
2b (R = H); 2c (R = CF3).) acquired in 0.1 M NBu4PF6 in CH2Cl2.
Scan rate: 100 mV/s.
The relatively low oxidation potential of the ruthenaindenes
may be rationalized by the ability of strongly electron-donating
organic ligands to stabilize the oxidized Ru3+ center. The
oxidation potential for complex 2c, where the aromatic rings
bear the most electron-withdrawing substituents (−CF3), is
significantly higher than for the other two complexes. This
suggests that substituents which make the aromatic ligand a
more electron-poor donor pull electron density away from the
Ru2+ center and make it more difficult to oxidize. Conversely,
the Ru2+ center in complex 2a, where the −OMe substituents
are electron-donating and make the aromatic ligand a more
electron rich donor, is the most easily oxidized of the
complexes examined in this study. All three complexes
exhibited an irreversible oxidation process at higher potentials
(between 0.25 and 0.70 V).
1
stated. H and 13C NMR spectra were referenced to residual solvent
resonances, 31P NMR spectra were referenced to external neat
trimethyl phosphite at δ 140.85, and 19F spectra were referenced to
external neat hexafluorobenzene at δ −164.9. Mass spectrometric
analyses were carried out at the Bioanalytical Mass Spectrometry
Facility, UNSW. Microanalyses were carried out at the Campbell
Microanalytical Laboratory, University of Otago, Otago, New
Zealand. Crystallographic analyses were performed on a Bruker
Kappa APEXII area detector diffractometer (Mo Kα radiation, λ =
0.71071 Å, T = 150 K). Crystallographic data are presented in Table
S1 in the Supporting Information. Electrochemistry was performed
using a Metrohm Autolab potentiostat connected to an electro-
chemical cell assembled in a nitrogen glovebox; the compound of
interest was dissolved in dry and degassed electrolyte solution (0.1 M
NBu4PF6 in dichloromethane). Cyclic voltammograms (CV) were
recorded with a glassy-carbon working electrode, a Pt/Ti-wire
auxiliary electrode, and an Ag/Ag+ quasi-reference electrode at a
scan rate of 100 mV s−1. An internal ferrocene/ferrocenium ion (Fc/
Fc+) standard was added to the sample solution at the end of each set
of measurements.
CONCLUSIONS
■
In this work, we have extended our study of ruthenaindenes
that are formed from the reaction of ruthenium butenynyl
complexes with dimethylmagnesium. We have developed a
new synthetic approach to ruthenium butenynyl complexes by
the reaction of dimethylruthenium complexes with butadiynes
in a protic solvent. This new route avoids the intermediacy of
ruthenium bis(acetylides), which are typically formed as
mixtures of cis and trans isomers, where only the cis isomer
reacts to form the desired butenynyl complexes. The butadiyne
precursors are readily available by the head-to-head Glaser
coupling of terminal acetylenes;23 thus, the new route provides
a more general synthesis of ruthenium butenynyl complexes
and ruthenaindenes.
cis-[RuMe2(PMe3)4],9 [Ru(CCPh)2(PMe3)4],19 and [Ru(η3-
15
−
PhCCCCH(Ph))(PMe3)4]+BF4
were prepared by literature
methods. 1-Ethynyl-4-methoxybenzene was purchased commercially
and used without further purification or prepared via a Pd(PPh3)4-
catalyzed cross-coupling reaction of 4-bromoanisole with ethynyl-
magnesium bromide.24 1-Ethynyl-4-(trifluoromethyl)benzene25 was
prepared by the PdCl2(PPh3)2-catalyzed Sonogashira coupling of 4-
bromobenzotrifluoride with trimethylsilylacetylene and subsequent
deprotection with K2CO3. 2,6-Lutidinium tetrafluoroborate,26 1,4-
diaryl-1,3-butadiynes,23 and halide-free dimethylmagnesium27 were
prepared according to literature procedures.
[Ru(η3-MeO-4-C6H4CCCCH(C6H4-4-OMe))(PMe3)4]+X−
−
Electrochemical analysis of the ruthenaindenes containing
different substituents on the benzene ring demonstrated that,
even though the substituents are remote from the ruthenium
(1a). X = BPh4 . [RuMe2(PMe3)4] (0.341 g, 0.783 mmol) and 1,4-
bis(4-methoxyphenyl)-1,3-butadiyne (0.205 g, 0.783 mmol) were
stirred in methanol (5 mL) at room temperature overnight, and the
E
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13
The product contained approximately 12% [RuH(PMe3)5]+ and
resulting yellow suspension was filtered. A solution of NaBPh4 (0.268
g, 0.783 mmol) in methanol (6 mL) was filtered and then added to
the above filtrate to afford [Ru(η3-MeO-4-C6H4CCCCH(C6H4-
was used without further purification for the synthesis of the
ruthenaindene [Ru(PhCC−CCH(C6H4)(PMe3)4] (2b).
NMR data for [RuH(PMe3)5]+ are as follows. 31P{1H} NMR (243
−
4-OMe))(PMe3)4]+BPh4 (1a BPh4−) as a bright yellow precipitate
which was collected by filtration, washed with methanol (3 mL), and
MHz, acetone-d6): δ −9.1 (d, 2JPP = 25 Hz, 4P, Peq), −22.2 (p, 2JPP
=
then dried in vacuo (0.676 g, 0.684 mmol, 87% yield). 31P{1H} NMR
1
27 Hz, 1P, Pax). H NMR (600 MHz, acetone-d6): δ 1.62 (m, 36H,
PCH3), 1.47 (d, 2JHP = 6 Hz, 9H, PCH3), −11.31 (dp, 2JHP = 74 Hz,
2JHP = 25 Hz, RuH). NMR data match those reported previously.13
[Ru(η3-CF3-4-C6H4CCCCH(C6H4-4-CF3))(PMe3)4]+X− (1c).
X = BPh4−. [RuMe2(PMe3)4] (0.320 g, 0.735 mmol) and 1,4-bis(4-
(trifluoromethyl)phenyl)-1,3-butadiyne (0.256 g, 0.757 mmol) were
stirred in methanol (8 mL) at room temperature overnight to afford a
dark red solution. A solution of NaBPh4 (0.264 g, 0.771 mmol) in
methanol (8 mL) was filtered and then added to the reaction mixture
to afford [Ru(η3-CF3-4-C6H4CCCCH(C6H4-4-CF3))(PMe3)4]+
2
2
(162 MHz, acetone-d6): δ 1.55 (dt, JPP = 33 Hz, JPP = 20 Hz, 1P,
Peq), −8.1 (dd, 2JPP = 33 Hz, 2JPP1 = 30 Hz, 2P, Pax), −15.4 (dt, 2JPP
=
2
30 Hz, JPP = 20 Hz, 1P, Peq). H NMR (400 MHz, acetone-d6): δ
7.77 (AA′XX′, 2H, o-ArH(alkene)), 7.72 (AA′XX′, 2H, o-
ArH(alkyne)), 7.34 (m, 8H, o-H(BPh4)), 7.08 (AA′XX′, 2H, m-
ArH(alkyne)), 7.03 (m, 1H, CCH), 7.01 (AA′XX′, 2H, m-
ArH(alkene)), 6.92 (m, 8H, m-H(BPh4)), 6.77 (m, 4H, p-
2
H(BPh4)), 3.87 (s, 3H, OCH3), 3.83 (s, 3H, OCH3), 1.84 (d, JHP
= 8 Hz, 9H, PCH3), 1.80 (d, 2JHP = 7 Hz, 9H, PCH3), 1.19 (apparent
triplet, splitting = 3 Hz), 18H, PCH3). The product contains
13
approximately 4% [RuH(PMe3)5]+ and was used without further
−
BPh4 (1c BPh4−) as an orange precipitate, which was collected by
purification.
−
X = BF4 . cis-/trans-[Ru(CCC6H4-4-OMe)2(PMe3)4] (3a; 0.303
filtration, washed with methanol (3, 10, and 5 mL), and then dried in
vacuo (0.409 g, 0.384 mmol, 52% yield). 31P{1H} NMR (162 MHz,
g, 0.454 mmol) and 2,6-lutidinium tetrafluoroborate (0.088 g, 0.454
mmol) were stirred in tetrahydrofuran (6 mL) overnight under an
atmosphere of nitrogen. The reaction mixture was evaporated to
dryness and the residue washed with pentane (30 mL) and diethyl
ether (30 mL). The crude material was recrystallized from acetone (5
mL) and pentane (5 mL) to afford [Ru(η3-MeO-4-C6H4CCC
2
2
acetone-d6): δ 0.8 (dt, JPP = 22 Hz, JPP = 33 Hz, 1P, Peq), −8.8
(apparent triplet, splitting = 32 Hz, 2P, Pax), −16.5 (dt, 2JPP = 22 Hz,
2JPP = 31 Hz, 1P, Peq). H NMR (400 MHz, acetone-d6): δ 8.07
1
(AA′XX′, 2H, o-ArH(alkene)), 8.05 (AA′XX′, 2H, o-ArH(alkyne)),
7.86 (AA′XX′, 2H, m-ArH(alkyne)), 7.78 (AA′XX′, 2H, m-
ArH(alkene)), 7.34 (m, 9H, CCH and o-H(BPh4)), 6.92 (m, 8H,
−
CH(C6H4-4-OMe))(PMe3)4]+BF4 (1a BF4−) as a bright yellow
crystalline solid (0.200 g, 0.265 mmol, 58%). MS (ESI, acetonitrile):
m/z 669.1883 ([Ru(MeOC6H4CCCCH(C6H4OMe))-
(PMe3)4]+, calcd for C30H51O2P4Ru 669.1886), 593.1446 ([Ru-
(MeOC6H4CCCCH(C6H4OMe))(PMe3)3]+, calcd for
C27H42O2P3Ru 593.1441), 517.1003 ([Ru(MeOC6H4CCCCH-
(C6H4OMe))(PMe3)2]+, calcd for C24H33O2P2Ru 517.0999),
441.0556 ([Ru(MeOC6H4CCCCH(C6H4OMe))(PMe3)]+,
calcd for C21H24O2PRu 441.0557). 31P{1H} NMR (243 MHz,
2
m-H(BPh4)), 6.78 (m, 4H p-H(BPh4)), 1.88 (d, JHP = 9 Hz, 9H,
2
PCH3), 1.85 (d, JHP = 7 Hz, 9H, PCH3), 1.21 (apparent triplet,
splitting = 3 Hz, 18H, PCH3). 19F NMR (565 MHz, acetone-d6): δ
−60.2 (CF3), −60.7 (CF3). The product contained approximately
13
15% [RuH(PMe3)5]+ and was used without further purification for
the synthesis of the ruthenaindene [Ru(CF3-4-C6H4CCCCH-
2
2
acetone-d6): δ 1.60 (dt, JPP = 33 Hz, JPP = 20 Hz, 1P, Peq), −8.0
(apparent triplet, splitting = 32 Hz, 2P, Pax), −15.4 (dt, 2JPP = 30 Hz,
(C6H3-4-CF3)(PMe3)4] (2c).
X = BF4−. cis-/trans-[Ru(CCC6H4-4-CF3)2(PMe3)4] (3c; 0.327
g, 0.440 mmol) and 2,6-lutidinium tetrafluoroborate (0.105 g, 0.539
mmol) were stirred in tetrahydrofuran (10 mL) overnight under an
atmosphere of nitrogen. The reaction mixture was diluted with
pentane (10 mL) and filtered, and the solid was washed with pentane
(10 mL) and then dried in vacuo. Recrystallization from acetone (5
mL)/pentane (10 mL) afforded [Ru(η3-CF3-4-C6H4CCCCH-
1
2JPP = 20 Hz, 1P, Peq). H NMR (600 MHz, acetone-d6): δ 7.77
(AA′XX′, 2H, o-ArH(alkene)), 7.73 (AA′XX′, 2H, o-ArH(alkyne)),
7.10 (AA′XX′, 2H, m-ArH(alkyne)), 7.04 (br d, 4JHP = 4 Hz, 1H, C
CH), 7.02 (AA′XX′, 2H, m-ArH(alkene)), 3.89 (s, 3H, OCH3), 3.83
2
2
(s, 3H, OCH3), 1.85 (d, JHP = 8 Hz, 9H, PCH3), 1.81 (d, JHP = 7
Hz, 9H, PCH3), 1.20 (apparent triplet, splitting = 3 Hz), 18H,
PCH3). 13C{1H} NMR (151 MHz, acetone-d6): δ 160.9 (p-
ArC(alkyne)), 159.9 (p-ArC(alkene)), 144.9 (m, RuCC), 134.2
(o-ArC(alkyne)), 132.3 (ipso-ArC(alkene)), 129.5 (CCH), 128.0
(o-ArC(alkene)), 121.0 (ipso-ArC(alkyne)), 115.7 (m-ArC(alkyne)),
115.2 (m-ArC(alkene)), 113.7 (m, ArCC), 57.5 (ArCC), 55.9
−
(C6H4-4-CF3))(PMe3)4]+BF4 (1c) as a bright yellow-orange solid
(0.240 g, 0.289 mmol, 66%). Anal. Calcd for C30H45BF10P4Ru
(831.45): C, 43.34; H, 5.46. Found: C, 43.23; H, 5.45. 31P{1H} NMR
(162 MHz, acetone-d6): δ 0.9 (dt, 2JPP = 22 Hz, 2JPP = 33 Hz, 1P, Peq),
−8.7 (apparent triplet, splitting = 32 Hz, 2P, Pax), −16.4 (dt, 2JPP = 22
1
(OCH3), 55.7 (OCH3), 25.1 (d, JCP = 26 Hz, PCH3), 24.0 (m,
PCH3), 18.4 (apparent triplet, splitting = 14 Hz, PCH3). 19F NMR
(565 MHz, acetone-d6): δ −149.0 (s, BF4).
2
1
Hz, JPP = 31 Hz, 1P, Peq). H NMR (400 MHz, acetone-d6): δ 8.09
(AA′XX′, 2H, o-ArH(alkene)), 8.07 (AA′XX′, 2H, o-ArH(alkyne)),
7.87 (AA′XX′, 2H, m-ArH(alkyne)), 7.79 (AA′XX′, 2H, m-
−
[Ru(η3-PhCCCCH(Ph))(PMe3)4]+BPh4 (1b BPh4). [Ru-
Me2(PMe3)4] (0.417 g, 0.958 mmol) and 1,4-diphenyl-1,3-butadiyne
(0.203 g, 1.00 mmol) were stirred in methanol (6 mL) at room
temperature overnight to afford a dark brown solution. A solution of
NaBPh4 (0.338 g, 0.988 mmol) in methanol (5 mL) was filtered and
then added to the reaction mixture to afford [Ru(η3-PhCCC
4
2
ArH(alkene)), 7.38 (br d, JHP = 4 Hz, 1H, CCH), 1.91 (d, JHP
= 9 Hz, 9H, PCH3), 1.88 (d, 2JHP = 7 Hz, 9H, PCH3), 1.23 (apparent
triplet, splitting = 3 Hz, 18H, PCH3). 13C{1H} NMR (101 MHz,
acetone-d6): δ 153.2 (RuCC), 142.1 (ipso-ArC(alkene)), 133.9
(ipso-ArC(alkyne)), 133.2 (o-ArC(alkyne)), 130.1 (q, 2JCF = 32 Hz, p-
−
CH(Ph))(PMe3)4]+BPh4 (1b BPh4) as a bright yellow precipitate,
which was collected by filtration, washed with methanol (3 mL), and
2
then dried in vacuo (0.699 g, 0.753 mmol, 79% yield). 31P{1H} NMR
ArC), 129.9 (CCH), 128.7 (q, JCF = 32 Hz, p-ArC), 127.4 (o-
2
2
ArC(alkene)), 127.0 (q, 3JCF = 4 Hz, m-ArC(alkene)), 126.8 (q, 3JCF
=
=
(243 MHz, acetone-d6): δ 1.40 (dt, JPP = 33 Hz, JPP = 21 Hz, 1P,
Peq), −8.3 (apparent triplet, splitting = 32 Hz, 2P, Pax), −15.8 (dt, 2JPP
4 Hz, m-ArC(alkyne)), 125.6 (q, 1JCF = 271 Hz, CF3), 125.2 (q, 1JCF
2
1
1
= 30 Hz, JPP = 21 Hz, 1P, Peq). H NMR (600 MHz, acetone-d6): δ
7.84 (m, 2H, o-ArH), 7.80 (m, 2H, o-ArH), 7.54 (m, 2H, m-ArH),
7.48−7.42 (m, 3H, p- and m-ArH), 7.34 (m, 8H, o-H(BPh4)), 7.28
(m, 1H, p-ArH), 7.16 (br d, 4JHP = 4 Hz, 1H, CCH), 6.92 (m, 8H,
271 Hz, CF3), 116.9 (ArCC), 63.1 (ArCC), 25.0 (d, JCP = 27
1
Hz, PCH3), 23.7 (d, JCP = 30 Hz, PCH3), 18.3 (apparent triplet,
splitting = 14 Hz, PCH3). 19F NMR (375 MHz, acetone-d6): δ −60.3
−
2
(CF3), −60.7 (CF3), −148.9 (BF4). Crystals of 1c BF4 suitable for
m-H(BPh4)), 6.78 (m, 4H, p-H(BPh4)), 1.86 (d, JHP = 8 Hz, 9H,
2
X-ray crystallography were grown from an acetone-d6 solution layered
PCH3), 1.81 (d, JHP = 7 Hz, 9H, PCH3), 1.21 (apparent triplet,
splitting = 3 Hz), 18H, PCH3).
with pentane.
F
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Article
[Ru(MeO-4-C6H4CCCCH(C6H3-4-OMe))(PMe3)4] (2a).
[Ru(CF3-4-C6H4CCCCH(C6H3-4-CF3))(PMe3)4] (2c).
A solution of dimethylmagnesium (58 mg, 1.1 mmol) and [Ru(η3-
A solution of dimethylmagnesium (24 mg, 0.44 mmol) and [Ru(η3-
−
MeO-4-C6H4CCCCH(C6H4-4-OMe))(PMe3)4]+ BPh4 (1a;
−
CF3-4-C6H4CCCC(H)(C6H4-4-CF3))(PMe3)4]+BPh4 (1c;
0.102 g, 0.103 mmol) in tetrahydrofuran (5 mL) was stirred under
an atmosphere of nitrogen overnight, in which time the solution
changed from orange to yellow. The solvent was removed under
reduced pressure, and the residue was extracted with benzene (3 × 3
mL). The benzene extract was filtered through diatomaceous earth
and the filtrate evaporated to dryness under reduced pressure to afford
a yellow gum, which was washed with pentane (3 × 3 mL) to afford a
yellow solid. The yellow solid was dissolved in tetrahydrofuran (3
mL), treated with methanol (0.6 mL) to decompose excess Me2Mg,
and then evaporated to dryness. The residue was extracted with
benzene (3 × 3 mL) and filtered through diatomaceous earth and the
filtrate evaporated to dryness under reduced pressure to afford
[Ru(MeO-4-C6H4CCCCH(C6H3-4-OMe))(PMe3)4] (2a) as a
yellow solid (38 mg, 55% yield). MS (ESI, acetonitrile): m/z
1359.3532 ([2 M + Na]+, calcd for C60H100NaO4P8Ru 1359.3507),
691.1702 ([M + Na]+, calcd for C30H50NaO2P4Ru 691.1705),
0.159 g, 0.149 mmol) in tetrahydrofuran (5 mL) was stirred under
an atmosphere of nitrogen overnight. The dark red suspension was
treated with methanol (approximately 150 μL) to decompose excess
Me2Mg. The solvent was removed under reduced pressure and the
residue extracted with benzene (3 × 3 mL, 1 mL) and then filtered
through diatomaceous earth. The orange filtrate was evaporated to
dryness under reduced pressure to afford [Ru(CF3-4-C6H4CCC
CH(C6H3-4-CF3))(PMe3)4] (2c) as an orange solid (23 mg, 21%
yield). Anal. Calcd for C30H44F6P4Ru (743.64): C, 48.46; H, 5.96.
Found: C, 48.46; H, 5.96. MS (ESI, acetonitrile): m/z 744.1336 (M+,
calcd for C30H44F6P4Ru 744.1344), 709.1158 ([M − PMe3
+
CH3CN]+, calcd for C29H38F6NP3Ru 709.1165), 668.0896 ([M −
PMe3]+, calcd for C27H35F6P3Ru 668.0899). 31P{1H} NMR (243
2
MHz, tetrahydrofuran-d8): δ −8.4 (t, JPP = 30 Hz, 2P, Pax), −13.4
(dt, 2JPP = 29 Hz, 2JPP = 16 Hz, 1P, Peq), −17.7 (dt, 2JPP = 29 Hz, 2JPP
1
= 16 Hz, 1P, Peq). H NMR (600 MHz, tetrahydrofuran-d8): δ 7.83
(br d, 4JHP = 4 Hz, 1H, H2), 7.58 (m, 3H, H7 and H13), 7.48 (m, 1H,
H12), 7.02 (m, 1H, H5), 6.99 (m, 1H, H4), 1.60 (d, 2JHP = 6 Hz, 9H,
2
PCH3), 1.57 (d, JHP = 5 Hz, 9H, PCH3), 1.02 (apparent triplet,
517.0997 ([Ru(MeOC6H4CCCCH(C6H3OMe)(PMe3)2
+
splitting = 3 Hz, 18H, PCH3). 13C{1H} NMR (151 MHz,
tetrahydrofuran-d8): δ 184.0 (C1), 164.1 (C6), 162.8 (C8), 155.8
(C7), 137.5 (C2), 131.9 (C11), 131.0 (C12), 127.9 (q, 2JCF = 32 Hz,
H]+, calcd for C24H33O2P2Ru 517.0999). 31P{1H} NMR (162 MHz,
2
tetrahydrofuran-d8): δ −7.6 (t, JPP = 28 Hz, 2P, Pax), −13.0 (dt, 2JPP
= 28 Hz, 2JPP = 15 Hz, 1P, Peq), −17.0 (dt, 2JPP = 28 Hz, 2JPP = 15 Hz,
1
3
C14), 127.0 (q, JCF = 271 Hz, C15), 125.8 (q, JCF = 4 Hz, C13),
125.4 (q, 1JCF = 272 Hz, C16), 122.9 (C3), 121.2 (C5), 118.1 (q, 3JCF
= 4 Hz, C4), 111.1 (C9), 94.9 (C10), 25.3 (PCH3), 24.9 (PCH3),
21.1 (PCH3). 19F NMR (565 MHz, tetrahydrofuran-d8): −60.0
(CF3), −61.3 (CF3).
1P, Peq). 1H NMR (400 MHz, tetrahydrofuran-d8): δ 7.38 (dt, 4JHP
=
4
7 Hz, JHP = 3 Hz, 1H, H7), 7.23 (AA′XX′, 2H, H12), 7.16 (m, 1H,
3
5
H2), 6.83 (dd, JHH = 8 Hz, JHP = 1.5 Hz, 1H, H5), 6.80 (AA′XX′,
2H, H13), 6.27 (dd, 3JHH = 8 Hz, 4JHH = 2 Hz, 1H, H4), 3.74 (s, 3H,
H16), 3.67 (s, 3H, H15), 1.58 (d, JHP = 5 Hz, 9H, PCH3), 1.55 (d,
2JHP = 5 Hz, 9H, PCH3), 1.04 (apparent triplet, splitting = 3 Hz, 18H,
2
cis-/trans-[Ru(CCC6H4-4-OMe)2(PMe3)4] (3a). cis-[Ru-
Me2(PMe3)4] (0.317 g, 0.728 mmol) and 1-ethynyl-4-methoxyben-
zene (0.205 g, 1.55 mmol) were stirred in tetrahydrofuran (10 mL)
overnight under an atmosphere of nitrogen. The reaction was
incomplete; therefore, an additional amount of 1-ethynyl-4-methox-
ybenzene (0.024 g, 0.18 mmol) was added and the mixture was stirred
overnight. The solvent was removed under reduced pressure and the
residue washed with pentane (2 × 20 mL) and then dried in vacuo to
afford cis-/trans-[Ru(CCC6H4-4-OMe)2(PMe3)4] (3a) as an off-
white solid (0.355 g, 0.532 mmol, 73%). The product contained 91%
cis and 9% trans isomers. MS (ESI, acetonitrile): m/z 669.1888 ([M
+ H]+, calcd for C30H51O2P4Ru 669.1886), 593.1446 ([M − PMe3 +
H]+, calcd for C27H42O2P3Ru 593.1441), 517.1003 ([M − 2PMe3 +
H]+, calcd for C24H33O2P2Ru 517.0999), 441.0557 ([M − 3PMe3 +
H]+, calcd for C21H24O2PRu 441.0557). 31P{1H} NMR (162 MHz,
PCH3). 13C{1H} NMR (101 MHz, tetrahydrofuran-d8): δ 184.3 (C1),
158.7 (C14), 155.5 (C3), 154.6 (C7), 154.2 (C6), 152.4 (C8), 131.7
(C12), 127.9 (C2), 122.0 (C5), 120.8 (C11), 114.3 (C13), 107.0
(C9), 105.6 (C4), 92.8 (C10), 55.2 (C16), 54.7 (C15), 26.1 (PCH3),
25.9 (PCH3), 21.4 (PCH3). Crystals of 2a suitable for X-ray
crystallography were grown from a pentane solution cooled to −20
°C.
[Ru(PhCCCCH(C6H4))(PMe3)4] (2b). [Ru(η3-PhCCC
−
CH(Ph))(PMe3)4]+BPh4 (1b; 0.142 g, 0.153 mmol) and Me2Mg
(0.042 g, 0.77 mmol) were stirred in tetrahydrofuran (5 mL) under an
atmosphere of nitrogen overnight. The yellow-orange suspension was
treated with methanol (0.2 mL) to decompose excess Me2Mg and
then evaporated to dryness under reduced pressure. The residue was
extracted with benzene (3 × 3 mL) and filtered through diatomaceous
earth, and the filtrate was evaporated to dryness under reduced
pressure. The residue was washed with pentane (1 and 3 mL) to
afford [Ru(PhCCCCH(C6H4))(PMe3)4] (2b) as a yellow solid
(0.044 g, 47% yield). NMR data matched those reported previously.9
2
tetrahydrofuran-d8): δ −4.0 (s, trans isomer), −8.6 (t, JPP = 29 Hz,
cis isomer), −12.2 (t, 2JPP = 29 Hz, cis isomer). 1H NMR (400 MHz,
tetrahydrofuran-d8): δ 7.04 (AA′XX′, 4H, o-ArH), 6.63 (AA′XX′, 4H,
m-ArH), 3.67 (s, 6H, OCH3), 1.59 (apparent triplet, splitting = 3 Hz,
18H, PCH3), 1.43 (m, 18H, PCH3). 13C{1H} NMR (101 MHz,
tetrahydrofuran-d8): δ 156.8 (p-ArC), 131.4 (o-ArC), 125.7 (m,
RuCC), 125.0 (ipso-ArC), 113.8 (m-ArC), 107.2 (m, RuCC),
55.1 (OCH3), 23.1 (m, PCH3), 21.4 (m, PCH3).
G
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Organometallics XXXX, XXX, XXX−XXX

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Article
2
cis-/trans-[Ru(CCC6H4-4-CF3)2(PMe3)4] (3c). cis-[Ru-
Me2(PMe3)4] (0.300 g, 0.689 mmol) and 1-ethynyl-4-
(trifluoromethyl)benzene (0.508 g, 2.99 mmol) were stirred in
tetrahydrofuran (5 mL) at 40 °C for 2 h under nitrogen. The reaction
mixture was evaporated to dryness under reduced pressure and then
washed with pentane (10 mL). The residue was extracted with
benzene (15 mL) and filtered through a pad of diatomaceous earth,
and the filtrate was evaporated to dryness under reduced pressure to
afford cis-/trans-[Ru(CCC6H4-4-CF3)2(PMe3)4] (3c) as a pale
orange solid (0.133 g, 0.179 mmol, 26%). The product contained 96%
cis and 4% trans isomers. Anal. Calcd for C30H44F6P4Ru (743.64): C,
48.46; H, 5.96. Found: C, 47.93; H, 6.36. 31P{1H} NMR (162 MHz,
13C{1H} NMR (151 MHz, acetone-d6): δ 355.3 (p, JCP = 14 Hz,
RuC), 131.0 (o-C (acetylide)), 130.4 (ipso-C (vinylidene)), 130.0
(m-C (vinylidene)), 129.3 (m-C (acetylide)), 128.6 (ipso-C
(acetylide)), 126.6 (p-C (vinylidene and acetylide)), 126.6 (o-C
2
(vinylidene)), 120.0 (RuCC), 114.9 (p, JCP = 23 Hz, RuCC),
113.4 (CH), 19.7 (br, PCH3). 19F NMR (376 MHz, acetone-d6): δ
−148.9 (BF4). Pink crystals of 4b suitable for X-ray crystallography
were grown from a solution in acetone which was vapor infused with
pentane.
ASSOCIATED CONTENT
* Supporting Information
■
sı
2
benzene-d6): δ −5.2 (s, trans isomer), −10.0 (t, JPP = 29 Hz, cis
2
1
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.organomet.9b00788.
isomer), −13.7 (t, JPP = 29 Hz, cis isomer). H NMR (400 MHz,
benzene-d6): δ 7.39 (AA′XX′, 4H, m-ArH), 7.32 (AA′XX′, 4H, o-
ArH), 1.41 (apparent triplet, splitting = 3 Hz, 18H, PCH3), 1.06 (m,
18H, PCH3). 13C{1H} NMR (101 MHz, benzene-d6): δ 136.3 (m,
NMR data for all new compounds, crystallographic data
for the complexes [Ru(η3-CF3-4-C6H4CCCCH-
1
RuC), 134.9 (ipso-ArC), 130.7 (o-ArC), 125.9 (q, JCF = 271 Hz,
(C6H4-4-CF3))(PMe3)4]+BF4 (1c), [Ru(MeO-4-
−
CF3), 125.3 (q, 3JCF = 4 Hz, m-ArC), 125.0 (q, 2JCF = 32 Hz, CCF3),
108.4 (RuCC), 22.6 (PCH3), 21.1 (PCH3). 19F NMR (376 MHz,
benzene-d6): δ −60.0 (s, CF3). Crystals of cis-3c suitable for X-ray
crystallography were grown from a toluene solution cooled to −20
°C.
C6H4CCCCH(C6H3-4-OMe))(PMe3)4] (2a), cis-
[Ru(CCC6H4-4-CF3)2(PMe3)4] (3c), [Ru(C
CH(C6H4-4-OMe))(CCC6H4-4-OMe)(PMe3)4]+
(4a), and trans-[Ru(CCH(Ph))(CCPh)-
(PMe3)4]+BF4 (4b) (PDF)
−
trans-[Ru(CCH(C6H4-4-OMe))(CCC6H4-4-OMe)-
(PMe3)4]+BF4− (4a). 2,6-Lutidinium tetrafluoroborate (0.118 g, 0.605
mmol) was added to a solution of cis-/trans-[Ru(CCC6H4-4-
OMe)2(PMe3)4] (3a; 0.379 g, 0.568 mmol, 30% trans isomer) in
tetrahydrofuran (2 mL) overnight under an atmosphere of nitrogen to
form a dark orange solution. Pentane (5 mL) was added, and the total
volume of the reaction mixture was reduced to 2 mL under reduced
pressure. The orange solid that formed was collected by filtration,
washed with pentane, and dried in vacuo. Recrystallization from
acetone (5 mL) and pentane (10 mL) afforded trans-[Ru(C
Accession Codes
CCDC 1966218−1966222 contain the supplementary crys-
tallographic data for this paper. These data can be obtained
free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by
emailing data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
−
CH(C6H4-4-OMe))(CCC6H4-4-OMe)(PMe3)4]+BF4 (4a) as a
AUTHOR INFORMATION
Corresponding Author
■
purple-red crystalline solid (17 mg, 23 μmol, 4% yield). MS (ESI,
acetonitrile): m/z 669.1889 ([Ru(CCHC6H4OMe)(C
CC6H4OMe)(PMe3)4]+, calcd for C30H51O2P4Ru 669.1886),
593.1449 ([Ru(CCHC6H4OMe)(CCC6H4OMe)(PMe3)3]+,
calcd for C27H42O2P3Ru 593.1441), 517.1007 ([Ru(C
CHC6 H4 OMe)(CCC6 H4 OMe)(PMe3 )2 ]+ , calcd for
C24H33O2P2Ru 517.0999), 441.0563 ([Ru(CCHC6H4OMe)-
(CCC6H4OMe)(PMe3)]+, calcd for C21H24O2PRu 441.0557),
385.0428 ([Ru(CCC6H4OMe)(PMe3)2]+, calcd for C15H25OP2Ru
Leslie D. Field − University of New South Wales, Sydney,
Australia; orcid.org/0000-0001-5519-5472;
Email: L.Field@unsw.edu.au
Other Authors
Hsiu L. Li − University of New South Wales, Sydney,
Australia; orcid.org/0000-0001-9361-3137
Synøve Ø. Scottwell − University of New South Wales,
Sydney, Australia; orcid.org/0000-0002-4769-8261
James D. Watson − University of New South Wales,
Sydney, Australia; orcid.org/0000-0003-4457-5722
Timothy E. Elton − University of New South Wales,
Sydney, Australia; orcid.org/0000-0003-4269-2765
Hon C. Yu − University of New South Wales, Sydney,
Australia; orcid.org/0000-0002-1408-3252
Mohan Bhadbhade − University of New South Wales,
Sydney, Australia; orcid.org/0000-0003-3693-9063
1
385.0424). 31P{1H} NMR (162 MHz, acetone-d6): δ −9.4 (br s). H
NMR (400 MHz, acetone-d6): δ 7.24 (AA′XX′, 2H, o-H (acetylide)),
7.13 (AA′XX′, 2H, o-H (vinylidene)), 6.90 (AA′XX′, 2H, m-H
(vinylidene)), 6.85 (AA′XX′, 2H, m-H (acetylide)), 5.29 (s, CH),
3.77 (s, 6H, 2 × OCH3), 1.79 (s, 36H, PCH3). 13C{1H} NMR (101
MHz, acetone-d6): δ 357.7 (m, RuC), 159.21 (p-C), 159.16 (p-C),
132.4 (o-C (acetylide)), 127.8 (o-C (vinylidene)), 121.4 (ipso-C),
121.3 (ipso-C), 119.8 (RuCC), 115.7 (m-C (vinylidene)), 114.9
(m-C (acetylide)), 112.9 (CH), 111.7 (p, 2JCP = 23 Hz, RuCC),
55.7 (2 × OCH3), 19.7 (br, PCH3). 19F NMR (565 MHz, acetone-
d6): δ −149.0 (BF4). Magenta crystals of 4a suitable for X-ray
crystallography were grown from a solution in acetone-d6 layered with
pentane.
−
trans-[Ru(CCH(Ph))(CCPh)(PMe3)4]+BF4 (4b). trans-
Complete contact information is available at:
[Ru(CCPh)2(PMe3)4] (3b; 0.306 g, 0.504 mmol) and 2,6-
lutidinium tetrafluoroborate (0.16 g, 0.82 mmol) were stirred in
tetrahydrofuran (20 mL) for 3 days under an atmosphere of nitrogen
to form a vivid pink solution. The solvent was removed under reduced
pressure, and the crude solid was recrystallized from acetone/pentane
https://pubs.acs.org/10.1021/acs.organomet.9b00788
Author Contributions
The manuscript was written through contributions of all
authors.
−
to afford trans-[Ru(CCH(Ph))(CCPh)(PMe3)4]+BF4 (4b)
as a pink crystalline solid (0.249 g, 0.358 mmol, 71%). Anal. Calcd for
C28H47BF4P4Ru (695.45): C, 48.36; H, 6.81. Found: C, 47.89; H,
7.26. 31P{1H} NMR (243 MHz, acetone-d6): δ −9.5 (br s). 1H NMR
(600 MHz, acetone-d6): δ 7.31 (m, 2H, m-H (vinylidene)), 7.30 (m,
2H, o-H (acetylide)), 7.28 (m, 2H, m-H (acetylide)), 7.20 (m, 2H, o-
H (vinylidene)), 7.19 (m, 1H, p-H (acetylide)), 7.11 (m, 1H, p-H
Funding
The authors thank the University of New South Wales for
funding and the Herriot Watt University (Scotland) for
supporting a student exchange (J.D.W.).
Notes
3
(vinylidene)), 5.36 (p, JHP = 1 Hz, = CH), 1.82 (br, 36H, PCH3).
The authors declare no competing financial interest.
H
https://dx.doi.org/10.1021/acs.organomet.9b00788
Organometallics XXXX, XXX, XXX−XXX

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ACKNOWLEDGMENTS
■
The authors thank Professor Barbara A. Messerle (Macquarie
University) for providing use of air-free electrochemical
equipment. The authors acknowledge the staff of the NMR
Facility and the X-ray Diffraction Laboratory within the Mark
Wainwright Analytical Centre at the University of New South
Wales.
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