Preparation of new acetylide and vinylidene complexes of ruthenium

Article abstract of DOI:10.1016/S0022-328X(99)00193-X

Monoacetylide RuCl(CCR)P₄ complexes (R=Ph, 4-MeC₆H₄, 1,4-C₆H₄CCH, SiMe₃, Bu^t or COOMe; P=P(OEt)₃ or P(OMe)₃) were prepared by allowing RuCl₂P

Full text of DOI:10.1016/S0022-328X(99)00193-X

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 585 (1999) 83–92
Preparation of new acetylide and vinylidene complexes of ruthenium
Gabriele Albertin *, Stefano Antoniutti, Emilio Bordignon, Manuel Granzotto
Dipartimento di Chimica, Uni6ersita` Ca’Foscari di Venezia, Dorsoduro 2137, I-30123 Venice, Italy
Received 20 February 1999
Abstract
Monoacetylide RuCl(CꢀCR)P4 complexes (R=Ph, 4-MeC6H4, 1,4-C6H4CꢀCH, SiMe3, But or COOMe; P=P(OEt)3 or
P(OMe)3) were prepared by allowing RuCl2P4 to react with terminal alkynes RCꢀCH in the presence of an excess of NEt3.
Dinuclear compounds [{Ru[P(OEt)3]5}2(m-1,4-CꢀCC6H4CꢀC)]Y2 (Y=PF6 or BPh4) were also prepared from the reaction of
RuCl2P4 with 1,4-HCꢀCC6H4CꢀCH. Treatment of RuCl2P4 with Li+[1,4-HCꢀCC6H4CꢀC]− afforded bis(alkynyl) Ru(1,4-
CꢀCC6H4CꢀCH)2P4 [P=P(OEt)3, P(OMe)3 or PPh(OEt)2] derivatives. Protonation reactions of monoacetylides RuCl(CꢀCR)P4
with CF3SO3H led to vinylidene [RuCl{ꢁCꢁC(H)R}P4]CF3SO3 [R=Ph, 4-MeC6H4 or 1,4-C6H4CꢀCH; P=P(OEt)3 or P(OMe)3]
1
complexes, which were fully characterised by IR and H-, 31P- and 13C-NMR spectra. © 1999 Elsevier Science S.A. All rights
reserved.
Keywords: Ruthenium; Alkynyl; Vinylidene; Dinuclear compounds
derivatives of iron(II), ruthenium(II) and osmium(II)
with these ligands have been reported by our research
1. Introduction
group. Following this initial work, we now report the
The chemistry of acetylide and vinylidene
synthesis and characterisation of new mono- and dinu-
organometallic complexes continues to attract interest,
clear acetylide complexes of ruthenium, together with
due to their potential use in several stoichiometric or
their reactivity studies, which yielded new vinylidene
catalytic transformations, such as dimerisation of alky-
derivatives.
nes to enynes or butatrienes [1], formation of unsatu-
rated carbene complexes [2] and metallocumulenes [3],
and other C–C coupling reactions [4]. In addition,
carbon-rich organometallic compounds are also attrac-
2. Experimental
tive, due to their potential for granting non-linear opti-
2.1. General considerations and physical measurements
cal [5], liquid crystal [6], mixed-valence or conducting
[7] properties.
These properties motivate constant studies on the
synthesis of mono- and dinuclear s-acetylide deriva-
tives and their chemical reactivity [1–4,8]. Important in
All synthetic work was carried out in an inert atmo-
sphere (argon, N2) using standard Schlenk techniques
or a Vacuum Atmosphere dry-box. Once isolated, the
complexes turned out to be quite air-stable and were
this context is the influence of the ancillary ligands,
stored at −20°C. All solvents used were dried over
generally mono-, bi- and polydentate phosphine, cy-
appropriate drying agents, degassed on a vacuum line,
clopentadienyl or arene rings. In contrast, very few
and distilled into vacuum-tight storage flasks. Di-
reports refer to phosphite P(OEt)3, substituted-phos-
phite PR(OR%)2 or PR2(OR%) ligands, and only recently
some studies [9] on acetylide, vinylidene and enynyl
ethoxyphenylphosphine was prepared by the method of
Rabinowitz and Pellon [10]; trimethyl- and tri-
ethylphosphite were Aldrich products purified by distil-
lation under nitrogen. Alkynes were Aldrich products,
used without any further purification. Lithium
* Corresponding author.
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00193-X

84
G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
acetylides Li+RCꢀC− (R=phenyl or p-tolyl) were
prepared by reacting a slight excess of the appropriate
acetylene (40 mmol) with lithium (35 mmol, 0.24 g) in
10 cm3 of THF. 1,4-Diethynylbenzene was prepared
following the method previously reported [11]. The
related lithium acetylide Li+[1,4-HCꢀCC6H4CꢀC]−
was prepared by reacting 1,4-diethynylbenzene (16
mmol, 2 g) with lithium (15 mmol, 0.104 g) in 30 cm3 of
THF. The reaction mixture was refluxed until all the
lithium had dissolved (about 8 h), and was kept under
argon. Other reagents were purchased from commercial
sources in the highest available purity and used as
received. IR spectra were recorded on Digilab Bio-Rad
FTS-40 or Nicolet Magna 750 FT-IR spectrophotome-
ters. NMR spectra (1H-, 13C-, 31P-) were obtained on a
Bruker AC200 spectrometer at temperatures varying
2.2.2. RuCl(CꢀCR)[P(OEt)3]4 (1) [R=SiMe3 (d), But
(e) or COOMe (f)]
These complexes were prepared like the related 1a–
1c by treating RuCl2[P(OEt)3]4 (0.6 mmol, 0.5 g) with
an excess of the appropriate alkyne (6 mmol) and an
excess of NEt3 (6 mmol, 0.83 cm3) and then refluxing
the resulting solution in THF (10 cm3) for 3 h. After
evaporation of the solvent at reduced pressure, the oil
obtained was chromatographed through a silica gel
column (20×2 cm) using a mixture of diethyl ether and
benzene (ratio 2:1) as eluent. The first eluate (50 cm3)
was evaporated to dryness, leaving an oily product that
could not be obtained as a solid. The spectroscopic
data, however, confirm the purity and formulation of
the products.
1
from −90 to +30°C, unless otherwise stated. H and
2.2.3. Ru(CꢀCPh)2[PPh(OEt)2]4
13C spectra are referred to internal TMS; 31P{1H}
chemical shifts are reported with respect to 85% H3PO4,
This complex [9b] was obtained in an attempt to
prepare the chloroacetylide RuCl(CꢀCPh)P4 derivative,
as follows: an excess of PhCꢀCH (6 mmol, 0.67 cm3)
and then an excess of NEt3 (6 mmol, 0.83 cm3) were
added to a solution of RuCl2[PPh(OEt)2]4 (0.6 mmol,
0.58 g) in 10 cm3 of THF, and the reaction mixture
refluxed for about 3 h. The solvent was removed under
reduced pressure, giving an oil which was triturated
with 5 cm3 of ethanol. After slow cooling of the result-
ing solution to −25°C, yellow microcrystals of the
compound were obtained; yield 83%.
with downfield shifts considered positive. The SwaN-MR
software package [12] was used to treat NMR data.
The conductivity of 10−3 mol dm−3 solutions of the
complexes in MeNO2 at 25°C was measured with a
Radiometer CDM 83 instrument.
2.2. Preparation of the complexes
Dichloro-compounds RuCl2[P(OEt)]4 and RuCl2P4
[P=P(OMe)3 or PPh(OEt)2] were prepared following
the method previously reported [9b,13].
Anal. Calc. for C56H70O8P4Ru: C, 61.4; H, 6.4.
Found: C, 61.3; H, 6.4%.
2.2.1. RuCl(CꢀCR)P4 (1–2) [P=P(OEt)3 (1) or
P(OMe)3 (2); R=Ph (a), 4-MeC6H4 (b) or
1,4-C6H4CꢀCH (c)]
2.2.4. [{Ru[P(OEt)3]5}2(v-1,4-CꢀCC6H4CꢀC)]Y2 (3)
(Y=PF6 or BPh4)
A 25 cm3 three-necked round-bottomed flask was
charged with RuCl2[P(OEt)3]4 (0.6 mmol, 0.5 g), 1,4-
HCꢀCC6H4CꢀCH (0.3 mmol, 37.8 mg), NaPF6 (1.8
mmol, 0.3 g), 10 cm3 of THF and NEt3 (6 mmol, 0.83
cm3). The resulting mixture was refluxed for 2 h 30 min,
and the solvent evaporated to dryness. The brown oil
obtained was treated with ethanol (5 cm3) and the
resulting solution stirred until a solid separated out,
which was crystallised from ethanol; yield]30% of
3-PF6. To the mother liquid an excess of NaBPh4 (2.4
mmol, 0.82 g) in 3 cm3 of ethanol was added and the
orange solid obtained was filtered and crystallised from
ethanol; yield ]35% of 3-BPh4.
To a solution of RuCl2P4 (0.6 mmol) in 10 cm3 of
THF were sequentially added first an excess of the
appropriate alkyne RCꢀCH (6 mmol) and then an
excess of NEt3 (6 mmol, 0.83 cm3), and the reaction
mixture was refluxed for about 50 min. The solvent was
removed under reduced pressure, giving an oil which
was triturated with 3 cm3 of ethanol. After cooling the
resulting solution to −25°C, a pale-yellow solid sepa-
rated out, which was crystallised from diethyl ether (5
cm3) and ethanol (5 cm3); yield from 30 to 40%.
Anal. Calc. for C32H65ClO12P4Ru (1a): C, 42.6; H,
7.3; Cl, 3.9. Found: C, 42.5; H, 7.3; Cl, 3.8%.
Anal. Calc. for C33H67ClO12P4Ru (1b): C, 43.3; H,
7.4; Cl, 3.9. Found: C, 43.2; H, 7.5; Cl, 3.8%.
Anal. Calc. for C34H65ClO12P4Ru (1c): C, 44.1; H,
7.1; Cl, 3.8.Found: C, 44.2; H, 7.1; Cl, 3.7%.
Anal. Calc. for C20H41ClO12P4Ru (2a): C, 32.7; H,
5.6; Cl, 4.8. Found: C, 32.5; H, 5.7; Cl, 4.6%.
Anal. Calc. for C21H43ClO12P4Ru (2b): C, 33.7; H,
5.8; Cl, 4.7. Found: C, 33.6; H, 5.8; Cl, 4.6%.
Anal. Calc. for C22H41ClO12P4Ru (2c): C, 34.9; H,
5.5; Cl, 4.7. Found: C, 34.7; H, 5.5; Cl, 4.6%.
Anal. Calc. for C70H154F12O30P12Ru2 (3-PF6): C,
36.9; H, 6.8. Found: C, 37.0; H, 6.9%. Anal. Calc. for
C118H194B2O30P10Ru2 (3-BPh4): C, 54.0; H, 7.5. Found:
C, 53.8; H, 7.5%.
2.2.5. Ru(1,4-CꢀCC6H4CꢀCH)2P4 (4–6) [P=P(OEt)3
(4), P(OMe)3 (5) or PPh(OEt)2 (6)]
An excess of Li+[1,4-HCꢀCC6H4CꢀC]− (3.6 mmol,
6.8 cm3 of a 0.53 mol dm−3 solution in THF) was
added to a solution of the appropriate complex

G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
85
RuCl2P4 (0.6 mmol) in 10 cm3 of THF, and the reac-
tion mixture refluxed for 1 h. The solvent was re-
moved under reduced pressure, giving an oil which
was treated with 5 cm3 of ethanol. The resulting solu-
tion was vigorously stirred until a red–brown solid
separated out, which was crystallised from diethyl
ether (5 cm3) and ethanol (5 cm3); yield 15–40%.
Anal. Calc. for C44H70O12P4Ru (4): C, 52.0; H, 6.9.
Found: C, 51.8; H, 7.0%. Anal. Calc. for
C32H46O12P4Ru (5): C, 45.3; H, 5.5. Found: C, 45.1;
H, 5.5%. Anal. Calc. for C60H70O8P4Ru (6): C, 63.0;
H, 6.2. Found: C, 63.1; H, 6.2%.
Scheme 1. P=P(OEt)3 (1) or P(OMe)3 (2); R=Ph (a), 4-MeC6H4 (b),
1,4-C6H4CꢀCH (c), SiMe3 (d), But (e) or COOMe (f).
Studies on the reaction course in the absence of
NEt3 indicate (by NMR, see below) the formation of
vinylidene
intermediates
[RuCl{ꢁCꢁC(H)R}P4]+
which, by deprotonation, give the final acetylide
derivatives 1, 2.
The activation of a terminal alkyne into a vinyli-
dene by dichloro complexes is not unexpected, and
probably takes place by the initial formation of a
2.2.6. [RuCl{ꢁCꢁC(H)R}P4]CF3SO3 (7–8)
[P=P(OEt)3 (7) or P(OMe)3 (8); R=Ph (a),
4-MeC6H4 (b) or 1,4-C6H4CꢀCH (c)]
h2-alkyne
complex
of
the
type
[RuCl(h2-
HCꢀCR)P4]+, followed by an intramolecular 1,2-[H]
shift [14] to give the vinylidene complex. This inter-
mediate may also be formed by a different pathway
involving oxidative addition of the alkyne to a Ru(II)
species to generate a Ru(IV) moiety, with subsequent
migration of the Ru–H hydride to the b-carbon of
the RuCꢀCR, as previously observed [15]. In every
case, the chloro-vinylidene [RuCl{ꢁCꢁC(H)R}P4]+
species is always formed (detected by NMR), but in
small amounts which do not allow its isolation in
pure form.
To a solution of the appropriate acetylide Ru-
Cl(CꢀCR)P4 (0.15 mmol) in 10 cm3 of diethyl ether
cooled to −80°C was added a slight excess of
CF3SO3H (0.16 mmol, 14.2 ml) and the reaction mix-
ture, brought to room temperature, was stirred for 1
h. A pink solid slowly separated out, which was
filtered and dried in vacuo; yield]80%.
Anal. Calc. for C33H66ClF3O15P4SRu (7a): C, 37.7;
H, 6.3; Cl, 3.4. Found: C, 37.6; H, 6.4; Cl, 3.4%.
Anal. Calc. for C34H68ClF3O15P4SRu (7b): C, 38.3;
H, 6.4; Cl, 3.3. Found: C, 38.1; H, 6.5; Cl, 3.2%.
Anal. Calc. for C35H66ClF3O15P4SRu (7c): C, 39.1;
H, 6.2; Cl, 3.3. Found: C, 39.0; H, 6.3; Cl, 3.2%.
Anal. Calc. for C21H42ClF3O15P4SRu (8a): C, 28.5;
H, 4.8; Cl, 4.0. Found: C, 28.3; H, 4.6; Cl, 3.9%.
Anal. Calc. for C22H44ClF3O15P4SRu (8b): C, 29.4;
H, 4.9; Cl, 4.0. Found: C, 29.5; H, 5.0; Cl, 3.9%.
Anal. Calc. for C23H42ClF3O15P4SRu (8c): C, 30.4;
H, 4.7; Cl, 3.9. Found: C, 29.9; H, 4.9; Cl, 3.9%.
Good analytical data were obtained for acetylide
complexes 1a–c, 2a–c, which are air-stable white or
pale yellow solids (the related 1d–f are oils), diamag-
netic and non-electrolytic. Their spectroscopic proper-
ties (IR and NMR) are reported in Table 1. The IR
spectra show only one band in the w(CꢀC) region, at
2098–2013 cm−1 for all the acetylides except for
RuCl(1,4-CꢀCC6H4CꢀCH)P4 1c and 2c complexes,
which exhibit two w(CꢀC) absorptions at 2085, 2040
(1c) and 2084, 2039 cm−1 (2c), and the w(CH) band
of the terminal acetylene end CꢀCH at 3250–3227
2.2.7. [RuCl{ꢁCꢁC(H)Ph}{P(OEt)3}4]BF4 (7a-BF4)
This compound was prepared exactly like the re-
lated triflate complex 7a using HBF4·Et2O instead of
CF3SO3H as the protonating agent; yield]80%
Anal. Calc. for C32H66BClF4O12P4Ru: C, 38.8; H,
6.7; Cl, 3.6. Found: C, 38.9; H, 6.8; Cl, 3.5%.
cm−1
.
The 13C-NMR spectra confirm the presence of the
acetylide ligand, showing the signals of the Ca and Cb
carbon atoms as quintets, respectively at 119–107
2
ppm, with a JCP value of 20 Hz, and 109–110 ppm,
3
with a JCP of about 2 Hz. In the case of 1,4-di-
ethynylbenzene derivative (1c), the 13C spectra also
show the signals of the Cg and Cd carbon atoms of
the acetylide ligand as singlets at 84.9 and 77.0 ppm,
respectively. In the temperature range from +30 to
−90°C, the 31P{1H}-NMR spectra appear as sharp
singlets, indicating the magnetic equivalence of the
four phosphorus atoms of the phosphite ligands.
On this basis, a geometry with the chloride and
acetylide ligands in a mutually trans position may
reasonably be proposed for all the complexes (Scheme
2).
3. Results and discussion
3.1. Preparation of acetylide deri6ati6es
Dichloro complexes RuCl2P4 react with terminal
alkynes in the presence of an excess of NEt3 to give
the mono-acetylide complexes RuCl(CꢀCR)P4, which
were isolated in good yield and characterised (Scheme
1). The reaction also proceeds with 1,4-diethynylben-
zene to afford the corresponding mono-acetylide con-
taining the acetylenic end-group.

Table 1
IR and NMR data for the ruthenium complexes
a
Compound
IR
1H-NMR b,c
Assignment l (J Hz)
Spin system 31P{1H}-NMR b,d
13C{1H}-NMR b,e
w (cm−1
)
Assignment
l (J Hz)
l (J Hz)
Assignment
1a
1b
RuCl(CꢀCPh)[P(OEt)3]4
2093s
w(CꢀC)
w(CꢀC)
4.26 (m)
1.22 (t)
4.26 (m)
POCH2CH3
POCH2CH3
POCH2CH3
A4
A4
132.3 (s)
132.4 (s)
RuCl(4-MeC6H4CꢀC)[P(OEt)3]4
2098s
109.5 (qnt, br)
3JCP=2
108.0 (qnt)
2JCP=20
61.3 (s)
Cb acetylide
Ca acetylide
2.23 (s)
1.21 (t)
4-CH3C6H4
POCH2CH3
POCH2CH3
4-CH3C6H4
POCH2CH3
21.1 (s)
16.5 (s)
1c
RuCl(1,4-CꢀCC6H4CꢀCH)[P(OEt)3]4
3227m
2085s
w(CH)
4.25 (m)
3.08 (s)
1.21 (t)
POCH2CH3
ꢀCH
A4
131.9 (s)
119.0 (qnt)
2JCP=20
110.7 (qnt)
3JCP=2
84.9 (s)
77.0 (s)
61.4 (s)
16.5 (s)
Ca acetylide
Cb acetylide
/
w(CꢀC)
w(CꢀCH)
2040w
POCH2CH3
Cg acetylide
Cd acetylide
POCH2CH3
POCH2CH3
1d
1e
1f
RuCl[CꢀCSi(CH3)3][P(OEt)3]4
RuCl[CꢀCC(CH3)3][P(OEt)3]4
RuCl[CꢀC(CO)OMe][P(OEt)3]4
RuCl(CꢀCPh)[P(OMe)3]4
2013s
2093s
w(CꢀC)
w(CꢀC)
4.42 (m) f
1.27 (t)
0.25 (s)
4.44 (m) f
1.29 (t)
0.26 (s)
4.23 (m)
3.49 (s)
1.23 (t)
3.82 (t)
POCH2CH3
POCH2CH3
Si(CH3)3
POCH2CH3
POCH2CH3
C(CH3)3
POCH2CH3
OCH3
POCH2CH3
POCH3
A4
A4
A4
A4
129.4 (s) f
133.8 (s) f
130.7 (s)
134.5 (s)
5
2076s
1674s
w(CꢀC)
w(CO)
(
2a
2089s
w(CꢀC)
110.9 (qnt)
3JCP=2
107.6 (qnt)
2JCP=20
53.0 (t)
Cb acetylide
Ca acetylide
POCH3
3
2b
2c
RuCl(4-MeC6H4CꢀC)[P(OMe3]4
2096s
w(CꢀC)
3.85 (t, br) f POCH3
2.16 (s)
3.82 (t) g
3.01 (s)
A4
A4
136.1 (s) f
136.1 (s) g
4-CH3C6H4
POCH3
ꢀCH
RuCl(1,4-CꢀCC6H4CꢀCH)[P(OMe)3]4
3250m
2084s
2039w
2103s
w(CH)
w(CꢀC)
w(CꢀCH)
w(CꢀC)
3-PF6 [{Ru[P(OEt)3]5}2(m-1,4-CꢀCC6H4CꢀC)](PF6)2
4.18 (m)
4.01 (m)
1.29 (t)
1.26 (t)
POCH2CH3
POCH2CH3
AB4
lA 129.7
lB 126.1
126.3 (m, br)
113.5 (m)
62.6 (s, br)
61.6 (s, br)
16.3 (s)
Cb acetylide
Ca acetylide
POCH2CH3
J
AB=53.5
POCH2CH3

Table 1 (continued)
3-BPh4 [{Ru[P(OEt)3]5}2(m-1,4-CꢀCC6H4CꢀC)]
2098s
w(CꢀC)
w(CH)
4.18 (m)
POCH2CH3
AB4
lA 130.4
lB 126.5
(BPh4)2
4.00 (m)
1.29 (t)
1.26 (t)
4.30 (m)
POCH2CH3
POCH2CH3
JAB=53.5
4
Ru(1,4-CꢀCC6H4CꢀCH)2[P(OEt)3]4
3275m
A4
136.6 (s)
124.3 (qnt)
2JCP=20
114.6 (qnt, br)
84.9 (s)
76.9 (s)
61.3 (s)
Ca acetylide
2070s
2034m
w(CꢀC)
w(CꢀCH)
3.08 (s)
1.21 (t)
ꢀCH
POCH2CH3
Cb acetylide
Cg acetylide
Cd acetylide
POCH2CH3
POCH2CH3
16.5 (s)
5
6
Ru(1,4-CꢀCC6H4CꢀCH)2[P(OMe)3]4
Ru(1,4-CꢀCC6H4CꢀCH)2[PPh(OEt)2]4
3273m
2073s
2030m
3289m
2064m
2030sh
w(CH)
3.83 (t)
3.14 (s)
POCH3
ꢀCH
A4
A4
114.8 (s)
152.8 (s)
w(CꢀC)
w(CꢀCH)
w(CH)
w(CꢀC)
w(CꢀCH)
4.15 (m)
3.68 (m)
3.16 (s)
POCH2CH3
/
ꢀCH
1.14 (m)
5.00 (qnt)
POCH2CH3
ꢁCH
7a
[RuCl{ꢁCꢁC(H)Ph}{P(OEt)3}4]CF3SO3
1653m (br)
w(CꢁC)
A4
A4
112.0 (s)
112.0 (s)
J
PH=3
4.25 (m)
1.32 (t)
4.98 (qnt)
POCH2CH3
POCH2CH3
ꢁCH
7a-BF4 [RuCl{ꢁCꢁC(H)Ph}{P(OEt)3}4]BF4
1663m (br)
w(CꢁC)
364.5 (qnt)
2JCP=18
109.6 (qnt)
3JCP=2
63.8 (s)
Ca vinylidene
Cb vinylidene
J
PH=3
4.22 (m)
POCH2CH3
POCH2CH3
ꢁCH
1.30 (t)
POCH2CH3
POCH2CH3
Ca vinylidene
16.2 (s)
7b
7c
[RuCl{ꢁCꢁC(H)4-MeC6H4}{P(OEt)3}4]
1663m
w(CꢁC)
4.95 (qnt)
JPH=3
4.23 (m)
A4
112.2 (s)
111.3 (s)
366.1 (qnt)
2JCP=18
109.5 (qnt)
3JCP=2
63.8 (s)
CF3SO3
5
POCH2CH3
Cb vinylidene
(
2.33 (s)
1.30 (t)
4-CH3C6H4
POCH2CH3
POCH2CH3
4-CH3C6H4
POCH2CH3
Ca vinylidene
21.12 (s)
16.2 (s)
8
[RuCl{ꢁCꢁC(H)1,4-C6H4CꢀCH}-{P(OEt)3}4]3229m
w(ꢀCH)
w(CꢀC)
w(CꢁC)
4.97 (qnt)
JPH=3
4.23 (m)
ꢁCH
A4
363.5 (qnt)
2JCP=18
109.4 (qnt)
3JCP=2
83.7 (s)
77.6 (s)
63.9 (s)
16.2 (s)
366.2 (qnt)
2JCP=18
109.8 (qnt)
3JCP=2
54.7 (t)
CF3SO3
2085vw
POCH2CH3
Cb vinylidene
1653m
3.14 (s)
1.31 (t)
ꢀCH
POCH2CH3
Cg vinylidene
Cd vinylidene
POCH2CH3
POCH2CH3
Ca vinylidene
8a
[RuCl{ꢁCꢁC(H)Ph}{P(OMe)3}4]CF3SO3
1670m
w(CꢁC)
5.17 (qnt)
ꢁCH
A4
116.0 (s)
J
PH=3
3.86 (t)
POCH3
Cb vinylidene
POCH3

88
G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
Scheme 2.
The easy synthesis of new mono-acetylides with
P(OEt)3 and P(OMe)3 ligands prompted us to extend our
study to include other phosphites such as PPh(OEt)2, but
in this case treatment of RuCl2[PPh(OEt)2]4 with alkyne
affords exclusively the bis(acetylide) [9b] Ru(CꢀCR)2P4
derivative in every set of conditions. The influence of the
phosphine ligand in determining the reaction course or
the stability of the final acetylide complex seems to be
crucial in the reaction of RuCl2P4 complexes with
alkyne, as shown by our results and by others involving
bidentate phosphine ligands [8b,c,16].
3.2. Preparation of dinuclear acetylide complexes
The synthesis of a RuCꢀCC6H4CꢀCRu unit was at-
tempted by reacting the RuCl(1,4-CꢀCC6H4CꢀCH)P4
1c, 2c species with an equimolar amount of RuCl2P4 in
the presence of NEt3, according to the results obtained
in the preparation of mono-acetylide complexes 1, 2.
Unfortunately, this approach failed, and only an in-
tractable mixture of products was obtained. We there-
fore reacted the 1,4-diethynylbenzene with two
equivalents of RuCl2[P(OEt)3]4 in the presence of NEt3
and also NaPF6 in THF, and obtained a red–orange
solution from which, after work-up, an orange micro-
crystalline solid was separated in relatively low yield
(]30%) (Scheme 3).
Analytical, spectroscopic and conductivity data sug-
gest a dinuclear complex of type 3, containing two
pentakis(phosphite)RuP5 fragments bonded by
a
–CꢀCC6H4CꢀC– bridging unit. The formation of
[{RuP5}2(m-1,4-CꢀCC6H4CꢀC)](PF6)2 (3-PF6) complexes
instead of the expected [RuClP4]2(m-1,4-CꢀCC6H4CꢀC)
was surprising, and may be explained on the basis of the
formation of free phosphite, due to some decomposition,
which substitutes the Cl ligand and affords the final
pentakis-complex. This dinuclear species 3 was also
obtained as BPh4 salt (3-BPh4), and both PF6− and
BPh4− compounds are air-stable solids soluble in polar
organic solvents, in which they behave as 1:2 electrolytes
[17]. The IR spectra show only one w(CꢀC) band at 2103
(3-PF6) and at 2098 cm−1(3-BPh4) of the diacetylide
ligand. Its presence is confirmed by the 13C spectra,
which show the Ca and Cb carbon atom signals
as multiplets at 113.5 and at 126.3 ppm, respect-
ively (Table 1). In the spectra, the signals at 84.9 and
77.0 ppm (singlets) observed in the mononuclear
complex 1c and attributed to the Cg and Cd carbon
atoms of the diacetylide ligand are absent. The
31P spectra show AB4 multiplets, which may be

G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
89
Scheme 3. P=P(OEt)3.
simulated with the parameters reported in Table 1 and
the CꢀCC6H4CꢀCH group appear as quintets at 124.3
(2JCP=20 Hz) and 114.6, respectively, due to the cou-
pling of four equivalent phosphorus nuclei, while the Cg
and Cd appear as singlets at 84.9 and 76.9 ppm.
Bis(acetylide) complexes 4–6 were reacted with
RuCl2P4, in an attempt to obtain a trinuclear derivative
of the type Cl–Ru–Ru–Ru–Cl or polynuclear ones
containing the diacetylide CꢀCC6H4CꢀC as bridging
unit. Unfortunately, although the reaction was carried
out in various conditions, changing the experimental
set-up and the ratio between the reagents, only un-
tractable mixtures of products were obtained and the
reaction was not investigated further.
confirm the proposed formulation (see Fig. 1 for the 31
P
spectrum of 3-PF6).
These
dinuclear
complexes
[{RuP5}2(m-1,4-
CꢀCC6H4CꢀC)](BPh4)2 (3) containing the pentakis
RuP5 fragment cannot be used to obtain polynuclear
complexes, owing to the reluctance of the phosphites to
be substituted by other ligands (acetylide), making 3
practically unreactive towards 1,4-diethynylbenzene.
We therefore prepared bis(acetylide) complexes trans-
Ru(1,4-CꢀCC6H4CꢀCH)2P4 4–6 with the aim of using
them to prepare polynuclear complexes. The acetylide
compounds were prepared by reacting dichloro com-
plexes RuCl2P4 with lithium acetylide, as shown in
Scheme 4.
3.3. Vinylidene deri6ati6es
The complexes are air-stable solids, characterised in
the usual way by analytical and IR and NMR data
(Table 1). The mutually trans position of the two
acetylide ligands is confirmed by the 31P spectra, which
appear as sharp singlets for all derivatives 4–6. The IR
spectra show only one w(CꢀC) band at 2073–2064
cm−1 and one w(CꢀCH) band at 2034–2030 cm−1 of
the CꢀCC6H4CꢀCH acetylide ligand. The medium in-
tensity band of w(CH) is also present at 3289–3273
cm−1. In the 13C-NMR spectra of 4, the Ca and Cb of
Arylacetylide RuCl(CꢀCR)P4 1a–b, 2a–b complexes
react with CF3SO3H or HBF4·Et2O to give vinylidene
derivatives [RuCl{ꢁCꢁC(H)R}P4]+ 7, 8, which were
isolated as CF3SO3− or BF4− salts and characterised
(Scheme 5). The reaction also proceeds with 1,4-di-
ethynylbenzene derivatives 1c, 2c, giving the corre-
sponding
complexes
7c,
8c
containing
an
alkyne–vinylidene ligand. Instead, alkynyls Ru-
Cl(CꢀCR)P4 1d–1f containing an alkyl-substituent,
Fig. 1. Observed (A) and calculated (B) 31P{1H}-NMR spectra of the compound [{Ru[P(OEt)3]5}2(m-1,4-CꢀCC6H4CꢀC)](PF6)2 (3-PF6) in
CD2Cl2 at 25°C. The simulated spectrum was obtained with the parameters reported in Table 1.

90
G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
Scheme 4. P=P(OEt)3 (4), P(OMe)3 (5) or PPh(OEt)2 (6).
Scheme 5. P=P(OEt)3 (7) or P(OMe)3 (8); R=Ph (a), 4-MeC6H4 (b) or 1,4-C6H4CꢀCH (c).
react with HBF4 or CF3SO3H at low temperature to
give the corresponding vinylidene complexes which,
however, are unstable over −10°C (by NMR) and
cannot be isolated in the solid state.
77.6 ppm, in agreement with the formulation proposed.
Lastly, a trans geometry for all the vinylidene com-
plexes in solution may be proposed, on the basis of the
sharp singlet appearing in the 31P{1H}-NMR spectra.
Acetylide complexes RuCl(CꢀCR)P4 also react with
other electrophilies reagents such as CF3SO3CH3, I2,
ArN2+, but in this case no stable vinylidene complexes
were obtained. The reactivity of dinuclear [{RuP5}2(m-
The new vinylidene complexes 7, 8 are pink solids
stable in air and in solution of polar organic solvents,
in which they behave as 1:1 electrolytes [17]. Their
characterisation is supported by analytical and spectro-
scopic data, reported in Table 1. In particular, the IR
spectra show the characteristic one or two medium-in-
tensity bands w(CꢁC) of the vinylidene ligand at
1672–1653 cm−1. In the spectra of alkyne–vinylidene
complexes 7c, 8c, w(CꢀC) absorptions at 2085–2062
and w(ꢀCH) bands at 3242–3229 cm−1 are also
1,4-CꢀCC6H4CꢀC)]2+
3 cations and bis(acetylide)
Ru(1,4-CꢀCC6H4CꢀCH)2P4 4–6 was also tested with
electrophilies (H+, CH3+, etc.), but whereas dinuclear 3
is unreactive towards protonation reactions, the
bis(acetylide) afforded an oily mixture of products
which were not characterised.
Vinylidene complexes 7, 8 may easily be deproto-
nated with base (NEt3) to give the starting acetylide
RuCl(CꢀCR)P4 derivatives (Eq. (1)).
1
present. The H-NMR spectra show the vinyl proton of
the ꢁCꢁC(H)R ligand in 7, 8 as a quintet at 5.17–4.95
ppm, due to the coupling to four equivalent P nuclei of
the phosphite ligands. In the spectra of 7c and 8c,
containing the ꢁCꢁC(H)1,4-C6H4CꢀCH group, the sig-
nal of the ꢀCH proton is also present as a singlet at
3.14 ppm. However, strong support for the formulation
of complexes 7, 8 as vinylidene comes from the
13C{1H}-NMR spectra, which show the characteristic
RuꢁCꢁcarbene carbon resonances as quintets at
[RuCl{ꢁCꢁC(H)R}P4]+ +NEt3
“[RuCl(CꢀCR)P4]+NHEt3+
(1)
Instead, the substitution reactions of the vinylidene
ligands are very slow in 7, 8, and the complexes
turn out to be quite robust in solution. This contrasts
with the properties shown by the comparable
[Ru(CꢀCR){ꢁCꢁC(H)R}P4]+ derivatives, previously
reported by us [9b], which showed the vinylidene
to be a labile ligand, easily replaceable by CO,
phosphite, nitrile and isocyanide. Instead, similar be-
haviour of our vinylidenes 7, 8 and of the known
2
369–363 ppm, with a JCP value of 18.0 Hz, and the
vinylic carbon resonances ꢁC(H)R as quintets near 109
3
ppm, with JCP of 2–3 Hz. Furthermore, in the 13C
spectra of the [RuCl{ꢁCꢁC(H)1,4-C6H4CꢀCH}P4]+
cation 7c (Fig. 2), the signals of Cg and Cd acetylide
carbon atoms are also observed as singlets at 83.7 and

G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
91
Fig. 2. 13C{1H}-NMR spectrum of the compound [RuCl{ꢁCꢁC(H)(1,4-C6H4CꢀCH)}{P(OEt)3}4]CF3SO3 (7c) in CD2Cl2 at 25°C.
[Ru(CꢀCR){ꢁCꢁC(H)R}P4]+ derivatives was observed
in the reaction towards amines or alcohols to give
carbene complexes. In both cases, the same unreactivity
was observed, and only decomposition took place over
a long reaction time in both types of vinylidene
derivatives.
References
[1] (a) C.S. Yi, N. Liu, A.L. Rheingold, L.M. Liable-Sands,
Organometallics 16 (1997) 3910. (b) C.S. Yi, N.H. Liu,
Organometallics 15 (1996) 3968. (c) C. Bianchini, P. Innocenti,
M. Peruzzini, A. Romerosa, F. Zanobini, P. Frediani,
Organometallics 15 (1996) 272. (d) H. Matsuzaka, Y. Takagi, Y.
Ishii, M. Nishio, M. Hidai, Organometallics 14 (1995) 2153. (e)
J.F. Corrigan, N.J. Taylor, A.J. Carty, Organometallics 13
(1994) 3778. (f) Y. Kishimoto, P. Eckerle, T. Miyatake, R.
Noyori, J. Am. Chem. Soc. 116 (1994) 12131. (g) M. Scha¨fer, N.
Mahr, J. Wolf, H. Werner, Angew. Chem. Int. Ed. Engl. 32
(1993) 1315. (h) D.L. Hughes, M. Jime´nez-Tenorio, G.J. Leigh,
A.T. Rowley, J. Chem. Soc. Dalton Trans. (1993) 3151. (i) L.D.
Field, A.V. George, G.R. Purches, I.H.M. Slip, Organometallics
11 (1992) 3019. (j) A.K. McMullen, J.P. Selegue, J.-G. Wang,
Organometallics 10 (1991) 3421.
4. Conclusions
The present investigations show that the use of
monodentate phosphite as ancillary ligand allows the
preparation of new monoacetylide RuCl(CꢀCR)P4
derivatives, including 1,4-diethynylbenzene as an
alkyne. Dinuclear complexes [{RuP5}2(m-1,4-CꢀCC6H4-
CꢀC)](PF6)2 and bis(alkynyl) Ru(1,4-CꢀCC6H4Cꢀ
CH)2P4 derivatives were also synthesised. Among the
properties shown by the monoacetylides, we emphasise
the fact that protonation reactions are easy, yielding
new stable vinylidene [RuCl{ꢁCꢁC(H)R}P4]CF3SO3
complexes.
[2] (a) C. Bianchini, A. Marchi, L. Marvelli, M. Peruzzini, A.
Romerosa, R. Rossi, Organometallics 15 (1996) 3804. (b) D.
Pilette, K. Ouzzine, H. Le Bozec, P.H. Dixneuf, C.E.F. Richard,
W.R. Roper, Organometallics 11 (1992) 809.
[3] (a) D. Touchard, S. Guesmi, M. Bouchaib, P. Haquette, A.
Daridor, P.H. Dixneuf, Organometallics 15 (1996) 2579. (b) V.
Cadierno, M.P. Gamasa, J. Gimeno, M. Gonzalez-Cueva, E.
Lastra, J. Borge, S. Garc´ıa-Granda, E. Pe´rez-Carren˜o,
Organometallics 25 (1996) 2137. (c) G. Roth, H. Fischer,
Organometallics 15 (1996) 1139. (d) M.I. Bruce, P. Hinterding,
P.J. Low, B.W. Skelton, A.H. White, J. Chem. Soc. Chem.
Commun. (1996) 1009. (e) M. Mart´ın, O. Gevert, H. Werner, J.
Chem. Soc. Dalton Trans. (1996) 2275. (f) D. Touchard, N.
Pirio, P.H. Dixneuf, Organometallics 14 (1995) 4920. (g) R.
Aumann, B. Jasper, R. Fro¨hlich, Organometallics 14 (1995)
3173.
Acknowledgements
This work was supported by the Ministero della
Ricerca Scientifica e Tecnologica (MURST), Rome. We
thank Dr Giuseppe Balacco (Menarini Ricerche S.p.A.)
[4] (a) M.A. Esteruelas, A.V. Go´mez, A.M. Lo´pez, J. Modrego, E.
On˜ate, Organometallics 16 (1997) 5826. (b) C. Slugovc, P.
Wiede, K. Mereiter, R. Schmid, K. Kirchner, Organometallics 16
for permission to use his
SwaN-MR software. We also
thank Daniela Baldan for technical assistance.

92
G. Albertin et al. / Journal of Organometallic Chemistry 585 (1999) 83–92
(1997) 2768. (c) V. Cadierno, M.P. Gamasa, J. Gimeno, M.C.
D.J. Williams, Organometallics 17 (1998) 1916. (f) L.-K. Liu,
K.-Y. Chang, Y.-S. Wen, J. Chem. Soc. Dalton Trans. (1998)
741. (g) M.I. Bruce, B.C. Hall, N.N. Zaitseva, B.W. Skelton,
A.H. White, J. Chem. Soc. Dalton Trans. (1998) 1793. (h) R.
Wiedemann, R. Fleischer, D. Stalke, H. Werner, Organometal-
lics 16 (1997) 866. (i) Y. Kawata, M. Sato, Organometallics 16
(1997) 1093. (j) T. Weyland, C. Lapinte, G. Frapper, M.J.
Calhorda, J.-F. Halet, L. Toupet, Organometallics 16 (1997)
2024. (k) M. Tamm, T. Jentzsch, W. Werncke, Organometallics
16 (1997) 1418. (l) S.-M. Yang, M.C.-W. Chan, K.-K. Cheung,
C.-M. Che, S.-M. Peng, Organometallics 16 (1997) 2819. (m)
H.M. Lee, J. Yao, G. Jia, Organometallics 16 (1997) 3927.
[9] (a) G. Albertin, S. Antoniutti, E. Bordignon, J. Organomet.
Chem. 513 (1996) 147. (b) G. Albertin, S. Antoniutti, E. Bor-
dignon, F. Cazzaro, S. Ianelli, G. Pelizzi, Organometallics 14
(1995) 4114. (c) G. Albertin, S. Antoniutti, E. Bordignon, E. Del
Ministro, S. Ianelli, G. Pelizzi, J. Chem. Soc. Dalton Trans.
(1995) 1783. (d) G. Albertin, S. Antoniutti, E. Bordignon, J.
Chem. Soc. Dalton Trans. (1995) 719. (e) G. Albertin, S. Anto-
niutti, E. Del Ministro, E. Bordignon, J. Chem. Soc. Dalton
Trans. (1992) 3203. (f) G. Albertin, P. Amendola, S. Antoniutti,
S. Ianelli, G. Pelizzi, E. Bordignon, Organometallics 10 (1991)
2876.
Lo´pez-Gonza´lez, J. Borge, J. Garc´ıa-Granda, Organometallics
16 (1997) 4453. (d) B.M. Trost, J.A. Flygare, J. Am. Chem. Soc.
114 (1992) 5476. (e) A.K. McMullen, J.P. Selegue, J.G. Wang,
Organometallics 10 (1991) 3421. (f) Y. Wakatsuki, H. Yamazaki,
N. Kumegawa, T. Satoh, J.Y. Satoh, J. Am. Chem. Soc. 113
(1991) 9604.
[5] (a) I.R. Whittall, A.M. McDonagh, M.G. Humphrey, M.
Samoc, Adv. Organomet. Chem. 42 (1998) 291. (b) C. Dhenaut,
I. Ledoux, D.W. Samuel, J. Zyss, M. Bourgault, H. Le Bozec,
Nature 374 (1995) 339. (c) N.J. Long, Angew. Chem. Int. Ed.
Engl. 34 (1995) 21. (d) S.R. Marder, Inorganic Materials, in:
D.W. Bruce, D. O’Hare (Eds.), Wiley, Chichester, UK, 1992, p.
115.
[6] (a) S. Takahashi, Y. Takai, H. Morimoto, K. Sonogashira, J.
Chem. Soc. Chem. Commun. (1984) 3. (b) A.A. Dembek, R.R.
Burch, A.E. Feiring, J. Am. Chem. Soc. 115 (1993) 2087. (c) M.
Altmann, U.H.F. Bunz, Angew. Chem. Int. Ed. Engl. 34 (1995)
569. (d) M. Altmann, V. Enkelmann, G. Lieser, U.H.F. Bunz,
Adv. Mater. 7 (1995) 726. (e) L. Oriol, J.L. Serrano, Adv. Mater.
7 (1995) 248.
[7] (a) J.L. Seesler, B. Wang, A. Harriman, J. Am. Chem. Soc. 117
(1995) 704. (b) A. Harriman, F. Odobel, J.-P. Sauvage, J. Am.
Chem. Soc. 117 (1995) 9461. (c) P. Belser, R. Dux, M. Baak, L.
De Cola, V. Balzani, Angew. Chem. Int. Ed. Engl. 34 (1995) 595.
(d) V. Grosshenny, A. Harriman, R. Ziessel, Angew. Chem. Int.
Ed. Engl. 34 (1995) 1100. (e) E.C. Constable, Angew. Chem. Int.
Ed. Engl. 30 (1991) 407.
[8] (a) D. Touchard, P. Haquette, A. Daridor, A. Romero, P.H.
Dixneuf, Organometallics 17 (1998) 3844. (b) I. de los Rios, M.
Jime´nez-Tenorio, M.C. Puerta, P. Valerga, Organometallics 17
(1998) 3356. (c) M.C.B. Colbert, J. Lewis, N.J. Long, P.R.
Raithby, M. Younus, A.J.P. White, D.J. Williams, N.N. Payne,
L. Yellowlees, D. Beljonne, N. Chawdhury, R.H. Friend,
Organometallics 17 (1998) 3034. (d) M.A. Esteruelas, A.V.
Go´mez, A.M. Lo´pez, E. On˜ate, N. Ruiz, Organometallics 17
(1998) 2297. (e) K.J. Harlow, A.F. Hill, T. Welton, A.J.P. White,
[10] R. Rabinowitz, J. Pellon, J. Org. Chem. 26 (1961) 4623.
[11] A.S. Hay, J. Org. Chem. 25 (1960) 637.
[12] G. Balacco, J. Chem. Inf. Comput. Sci. 34 (1994) 1235.
[13] W.G. Peet, D.H. Gerlach, Inorg. Synth. 15 (1974) 38.
[14] J. Silvestre, R. Hoffmann, Helv. Chim. Acta 68 (1985) 1461.
[15] (a) I. de los Rios, M. Jime´nez-Tenorio, M. Carmen-Puerta, P.
Valerga, J. Chem. Soc. Chem. Commun. (1995) 1757. (b) I. de
los Rios, M. Jime´nez-Tenorio, M. Carmen-Puerta, P. Valerga, J.
Am. Chem. Soc. 119 (1997) 6529.
[16] (a) D. Touchard, P. Haquette, S. Guesmi, L. Le Pichon, A.
Daridor, L. Toupet, P.H. Dixneuf, Organometallics 16 (1997)
3640. (b) O. Lavastre, J. Plass, P. Bachmann, S. Guesmi, C.
Moinet, P.H. Dixneuf, Organometallics 16 (1997) 184.
[17] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
.
.