C-H and C-C bond activations of terminal alkynes in the presence of a butterfly-shaped heteronuclear Ru3Au cluster

Article abstract of DOI:10.1016/j.jorganchem.2011.08.003

The reaction of compound [Ru₃(CO)₁₀(μ-Cl)(μ- AuPPh₃)] (1) with terminal alkynes HCCR; (R = C₆H ₄-4-CH₃, C₆H₃-2,5-(CH ₃)₂, C₆H₂-2,4,5-(CH ₃)₃, C(CH₃) = CH₂, Si(CH ₃)₃), under very mild conditions yielded isostructural compounds [Ru₃(CO)₉(μ-AuPPh₃) (μ₃-η² - CCR)] (R = C₆H ₄-4-CH₃ (2), C₆H₃-2,5-(CH ₃)₂ (3), C₆H₂-2,4,5-(CH ₃)₃ (4), C(CH₃)CH₂ (5), Si(CH ₃)₃) (6)) respectively; where the alkynes suffer oxidative additions to the metallic fragment coordinating as acetylide groups in a μ₃-η²-perpendicular fashion by breaking the C _(sp)-H bond of the alkynes. The AuPPh₃ fragment remains without change in all compounds. All of these clusters have been characterized in solution by i.r. and n.m.r. spectroscopy and their structures have been established by single crystal X-ray diffraction studies.

Full text of DOI:10.1016/j.jorganchem.2011.08.003

Journal of Organometallic Chemistry 696 (2011) 4070e4078
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
CeH and CeC bond activations of terminal alkynes in the presence
of a heteronuclear Ru3Au cluster
Micaela HernándezeSandoval a, Francisco J. ZunoeCruz a, María J. RosaleseHoz b, Marco A. Leyva b,
,
Noemi Andrade a, Verónica Salazar a, Gloria SánchezeCabrera a
*
a Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Ciudad Universitaria, Km 4.5 Carretera PachucaeTulancingo, Pachuca Hgo., 42184, Mexico
b Departamento de Química, Centro de Investigación y Estudios Avanzados del I. P. N., Apdo. postal 14-740, 07000 México D. F., Mexico
a r t i c l e i n f o
a b s t r a c t
Article history:
The reaction of compound [Ru3(CO)10
(
m
eCl)(
m
eAuPPh3)] (1) with terminal alkynes HC^CR; (R ¼ C6H4e4
Received 4 May 2011
Received in revised form
29 July 2011
eCH3, C6H3e2,5e(CH3)2, C6H2e2,4,5e(CH3)3, C(CH3) ¼ CH2, Si(CH3)3), under very mild conditions yiel-
ded isostructural compounds [Ru3(CO)9(
m
eAuPPh3)(
m
3eh2eteC^CR)] (R ¼ C6H4e4eCH3 (2), C6H3e2,5
e(CH3)2 (3), C6H2e2,4,5e(CH3)3 (4), C(CH3)]CH2 (5), Si(CH3)3) (6)) respectively; where the alkynes
suffer oxidative additions to the metallic fragment coordinating as acetylide groups in a
Accepted 1 August 2011
m
3eh2
eperpendicular fashion by breaking the C(sp)eH bond of the alkynes. The AuPPh3 fragment remains
without change in all compounds. All of these clusters have been characterized in solution by i.r. and
n.m.r. spectroscopy and their structures have been established by single crystal Xeray diffraction studies.
Ó 2011 Elsevier B.V. All rights reserved.
Dedicated to Professor Kenneth G. Caulton,
on the occasion of his 70th birthday, in
recognition of his many contributions to the
field of organometallic chemistry.
Keywords:
Heteronuclear clusters
Ruthenium
Gold
Alkynes
Acetylides
1. Introduction
could direct and/or modify the substrateecatalyst interactions in
catalytic processes for example in carbonylations [11], hydrogena-
In the last three decades, the activation of CeH bonds of alkenes
and alkynes promoted by transition-metal cluster complexes has
been a major research theme in organometallic chemistry, as can be
appreciated in the literature [1e7]. The alkyneecomplexes
obtained from these reactions have been considered as useful
models for the chemisorption of small molecules on metal surfaces
and as examples of reactions where carbonecarbon triple bond
activation and reduction reactions occur [1]. Studies carried out so
far involve both homoe and heteronuclear clusters [8,9], the
potential advantage of this polynuclear compounds is related to the
fact that several metal atoms linked together can provide specific
sites of interaction between organic molecules and clusters [10];
besides the insertion of a different type of metal (heterometallic
clusters) gives an inherit polarity to the heterometallic bond, which
tions or HDS reactions of organic substrates [12].
To take advantage of this inherit polarity of the heterometallic
bond in catalytic processes, the catalyst must be stable enough to
produce the desire transformation in the substrate. It is well known
that the carbonyl tetranuclear fragment Ru3(AuPPh3) lacks of
kinetic stability since easily transforms by breaking its RueAu and
AueP bonds [13], avoiding its possible use as catalyst. Therefore the
substitution of carbonyl ligands in this cluster by diphosphines or
acetylides enhances the metallic core stability [14e16].
Thus, the potential application of alkyne clusters in catalysis
leads to the study of these systems, for example the synthesis of
homoe and heteronuclear transition metal carbonyl cluster
involving different types of main group heteroatoms, bonded to the
metal core, have shown unique catalytic properties [11,17e21].
Several mixed RueAu metal clusters containing hydride or carbon
atoms [22e25], thiolates [26], diphosphines [27] and alkynes
[28e31] among other ligands [32,33] have been reported else-
* Corresponding author. Tel.: þ52 771 7172000x2204, þ52 1771 1300735 (cell);
fax: þ52 771 7172000x6502.
where. Besides,
a
novel dynamic process operating in the
E-mail address: gloriasa@uaeh.edu.mx (G. SánchezeCabrera).
[Fe3(CO)9( eAuPPh3)(m
m
3eh2eteC^CBut)] cluster has been
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.08.003

M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
4071
Scheme 1. Synthesis of the acetylide rutheniumegold clusters 2e6.
Table 1
1H, 31P{1H}, 29Si{1H} and 13C{1H} NMRa data for compounds 2e6.
Compound
1H
J(Hz)
d
(ppm)
31P{1H}
d
(ppm)
29Si{1H}
J(Hz)
d
(ppm)
13C{1H}
J(Hz)
d
(ppm)
[Ca þ Cb]
{CaꢀCb}
2
7.50 (m, 15H, Ph)
62.0 (s)
e
171.7 (s, Ca)
138.0 (s, C(4))
134.1 (d, Co)
131.4 (d, Cp)
4J
131.1 (s, C(2, 6))
129.5 (s, C(3, 5))
[271.9]
{71.5}
0
7.44 (HAA , 2H, H(2,6))
¼ 2.3
13Ce31
P
0
7.13 (HBB , 2H, H(3,5))
J
AB, JA B ¼ 7.9, JAA ¼ 6.2, JBB ¼ 1.8
2J
¼ 14.6
0
0
0
0
13Ce31
P
2.37 (s, 3H, CH3(40))
133.0 (s, C(1))
131.2 (d, Ci)
129.3 (d, Cm
)
3J
¼ 10.8
13Ce31
P
1J
¼ 48.4
100.2 (s, Cb)
13Ce31
P
21.4 (s, CH3(40))
131.2 (d, Ci)
3
7.50 (m, 15H, Ph)
7.21 (s, 1H, H(2))
7.11 (d, 1H, H(5))
3J1He1H ¼ 7.4
61.9 (s)
e
172.2 (s, Ca)
135.6 (s, C(1))
135.3 (s, C(3))
134.9 (s, C(6))
134.0 (d, Co)
[268.5]
{75.9}
1J
¼ 48.5
13Ce31
P
129.5 (s, C(4))
129.3 (d, Cm
3J
)
13Ce31
P
6.95 (d, 1H, H(4))
3J1He1H ¼ 7.4
¼ 11.2
2J
¼ 14.5
128.5 (s, C(5))
96.3 (s, Cb)
13Ce31
P
2.52 (s, 3H, CH3(30))
2.29 (s, 3H, CH3(60))
133.3 (s, C(2))
131.4 (d, Cp)
22.3 (s, CH3(50))
21.0 (s, CH3(20))
131.3 (d, Ci)
4J
¼ 2.1
13Ce31
P
4
7.51 (m, 15H, Ph)
7.17 (d, 1H, H(6))
7.00 (d, 1H, H(3))
2.49 (s, 3H, CH3(20))
2.25 (s, 3H, CH3(40))
2.20 (s, 3H, CH3(50))
62.5 (s)
e
171.7 (s, Ca)
136.5 (s, C(1))
135.3 (s, C(5))
134.3 (s, C(4))
134.0 (d, Co)
[268.3]
{75.2}
1J
¼ 48.4
13Ce31
P
131.0 (s, C(3))
129.2 (d, Cm
3J
)
¼ 11.5
13Ce31
P
2J
¼ 14.6
96.5 (s, Cb)
13Ce31
P
133.8 (s, C(6))
132.5 (s, C(2))
131.3 (d, Cp)
22.1 (s, CH3 (20))
19.5 (s, CH3 (40))
19.3 (s, CH3 (50))
4J
¼ 2.3
13Ce31
P
5
7.47 (m, 15H, Ph)
5.26 (s, 1H, CH2cis
61.7 (s)
62.3 (s)
e
172.9 (s, Ca)
139.0 (s, C(1))
134.0 (d, Co)
131.0 (d, Ci)
[275.6]
{70.2}
)
1J
¼ 48.3
13Ce31
P
5.14 (m, 1H, CH2trans
)
129.2 (d, Cm
)
4J1He1H ¼ 1.7
2J
¼ 14.6
3J
¼ 10.8
13Ce31
P
13Ce31P
2.15 (s, 3H, CH3)
131.3 (d, Cp)
117.9 (s, CH2)
102.7 (s, Cb)
26.7 (s, CH3)
131.2 (d, Ci)
4J
¼ 2.3
13Ce31
P
6
7.47 (m, 15H, Ph)
0.32 (s, 9H, CH3)
0.8 (s)
184.5 (s, Ca)
134.0 (d, Co)
[267.5]
{101.5}
2J
29Sie1H
¼ 6.6
1J
¼ 48.4
29Sie1H
13Ce31P
2J1He29 ¼ 6.6
2J
¼ 13.2
2J
¼ 14.6
129.2 (d, Cm
)
Si
13Ce31P
2J1He29 ¼ 13.2
131.3 (d, Cp)
4J
¼ 2.3
3J
¼ 10.8
Si
13Ce31P
1J1He13 ¼ 119.9
83.0 (s, Cb)
C
13Ce31P
1D13/12C ¼ ꢀ1.1 ppb
1.6 (s, 3C, CH3)
a
Obtained at r. t. in CDCl3. (s) singlet, (d) doublet, (m) multiplet, o, ortho; p, para; m, meta; i, ipso.

4072
M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
described, which involves the reversible rupture of a AueFe/
AueC(acetylide) bonds [34]. Examples like this may produce useful
information about bond cleavage that take place between the
metallic fragment and organic substrate in catalytic reactions.
Despite all cluster reactions involving terminal alkynes that
have been described [8,35]; there are some examples of RueAu
tetranuclear complex with this type of ligands [36]. The methods to
produce the desire Ru3AueAcetylide clusters mainly have been
based on reactions between [Ru3(CO)12] or [Ru3(CO)10(NCMe)2] and
an Auealkynyl ligand [15,16] or between the hydride acetylide
ruthenium cluster and a suitable Au fragment as AuClPPh3 [29] or
[AuPPh3]3Oþ [37]. Since the major previously reported synthetic
method to prepare Ru3Au acetylide complexes involves the prep-
aration of a suitable goldealkynyl precursor followed by a reaction
with the Ru3 homonuclear cluster [15,16,27,38,39], this prevents its
wide use to produce this type of compounds. Therefore, in an effort
to expand the available information on these systems, in this paper
we report the synthesis and characterization of five new tetranu-
clear heterometallic rutheniumegold clusters complexes contain-
ing acetylide ligands that arise from the cleavage of the C(sp)eH
Fig. 1. 1H NMR spectrum in the methyl region for compound 6.
bonds of terminal alkynes: [Ru3(CO)9(meAuPPh3)(m
3eh2ete
C^CR)] (R ¼ C6H4e4eCH3 (2), C6H3e2,5e(CH3)2 (3), C6H2e2,
4,5e(CH3)3 (4), C(CH3)]CH2 (5), Si(CH3)3) (6)). All compounds
were prepared under mild conditions by the in situ reaction of
compound [Ru3(CO)10(meCl)(meAuPPh3)] (1) and 1eetynyle
2emethylbenzene, 1eetynyle2,5edimethylbenzene,1eetynyle2,
4,5etrimethylbenzene, 2emethyle1ebutene3eyne or trime-
thylsilylacetylene respectively. All synthesized compounds were
characterized in solution by Infrared and 1H, 13C{1H}, 31P{1H} and
29Si{1H} NMR spectroscopy. Full assignment of carbon atoms for all
compounds was accomplished by 2eD heteronuclear correlation
experiments. The molecular structures of all compounds in the
solid state were determined by single crystal Xeray diffraction
studies.
2. Results and discussion
Treatment of a CH2Cl2 solution of [Ru3(CO)10(meCl)(meAuPPh3)]
(1), prepared in situ as previously described [26] with an excess of
the appropriate terminal alkyne at room temperature (r. t.) for 2 h
in the presence of Me3NO as activating agent, leads to the formation
of the new clusters [Ru3(CO)9(meAuPPh3)(m
3eh2eteC^CR)] (R]
C6H4e4eCH3 (2), C6H3e2,5e(CH3)2 (3), C6H2e2,4,5e(CH3)3 (4),
C(CH3)]CH2 (5), Si(CH3)3) (6)) respectively in moderated yields
(Scheme 1), In the case of methylated aryl series small amounts of
isolobal compounds were observed, in which the AuPPh3 fragment
is replaced by a hydride ligand. In each reaction the main product is
obviously derived from the C(sp)eH bond cleavage in every alkyne
and the substitution of the chlorine atom in the parent cluster. We
employed different substituents: a series of variously methylated
aryl derivatives, an olefinic fragment and a silicon group, to see if
any steric or electronic inductive effect on the triple bond towards
the reactivity of the heteronuclear cluster could be observed.
The symmetry of the i.r. spectra of all complexes is similar to
those of the previously reported compounds [Ru3(CO)9( eAuPPh3)
m
(m
3eh2eteC^CBut)] [29] and [Os3(CO)9( 3eh2ete
m
eAuPPh3)(m
C^CPh)] [30] (see experimental section). All compounds have
isolobal structures to the well known trinuclear hydride acetylide
complexes [Ru3(CO)9(
m
eH)(
m
3eh2eteC^CR)] (R ¼ But, SiMe3,
SiPh3 [8], and C6H4e4eCH3, C6H3e2,5e(CH3)2, C6H2e2,4,5e(CH3)3
(this work, see experimental section). There was no evidence of any
influence of the substituent in the alkyne, that affects the CO stretch
frequency, but the presence of a gold atom instead of the hydride
ligand on the metallic skeleton indeed lowers the CO stretching
frequencies.
Fig. 2. 29Si NMR spectra for 6. CO and AuPPh3 groups in the structure have been
omitted for clarity.

M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
4073
The NMR spectroscopic data for compounds 2e6 are given in
Table 1. All spectra were obtained at r. t. in CDCl3. The 31P{1H} NMR
spectra of all compounds showed singlet signals between 61.9 and
62.5 ppm, indicating that the gold phosphine group remain coor-
dinated to the ruthenium cluster. Chemical shifts are similar to
1D13/12C ¼ ꢀ1.1 ppb, in which the negative sign denotes a low
frequency shift with respect to the lighter isotope [41]. Also, it was
possible to observed another pair of satellites assigned to the
coupling with the 29Si nuclei, with a 2J1He29 ¼ 6.6 and 13.2 Hz, with
Si
relative intensities of 2:1 (6.6:13.2 Hz).
those described for other clusters containing a
meAuPPh3 bridge
To corroborate the assignment and the values of this 1He29Si
group [24,25]. The change of substituents in the acetylide fragment,
coupling constants, we carried out several 29Si NMR experiments
did not affect the 31P chemical shift.
changing the values of the coupling constant to acquire each of the
The 1H NMR spectrum for compound 2 showed two signals at
7.44 and 7.13 ppm, belonging to the characteristic AA’BB’ system of
the peMe phenyl ring, the reported coupling constants were
determined using a simulation NMR program [40]. The proton NMR
spectra for compounds 3 and 4 showed the characteristic signals for
substituted phenyl rings. The 1H NMR spectrum for compound 5
showed a multiple signal at 5.14 ppm coupled to the methyl group
to four bonds in a zigezag mode; this signal was assigned to the
CH2tras and corroborated by a 2DeNOESY experiment. In the 1H
NMR spectrum for compound 6 a singlet at 0.32 ppm was observed
and it was assigned to the methyl groups in the silyl fragment
29Si spectrums, (Fig. 2). We found that using J1He29 of 7.0 and
2
Si
13.0 Hz the intensity of the silicon signal is maximized, confirming
the values found in the 1H spectrum. This can be explained on the
magnetically nonequivalent methyl groups, bonded to the Si atom,
two of them equal to each other (CH3A) and different to the third
one (CH3B) (see structure in Fig. 2).
The 13C{1H} NMR spectra of compounds 2e6 showed the char-
acteristic chemical shifts for Ca and Cb (acetylide carbons). The d(Cb)
is shifted to higher frequencies in the silyl heteronuclear
compounds respect to their isolobal analogs with R ¼ SiMe3 or
SiPh3, while the
d(Ca) remains almost invariable [8]. Also,
(Fig. 1); this signal showed a set of satellites caused by the coupling
d
(Ca) þ
d
(Cb) and
d
(Ca) ꢀ
d(Cb) values have been proposed to be
1
with 13C nuclei with a J1He13 coupling of 119.9 Hz. This set of
related to the total charge alteration and the polarization of the
C^C triple bond respectively [2]. In our compounds, we found that
the polarization of the acetylide CeC bond follow the tendency
6 > 3> 4 > 2 > 5; with compounds 5 and 6 showing the largest DDd
C
satellites are unsymmetrically centered around the signal, which is
characteristic for an isotopomeric effect 1 13/12C (secondary isotope
D
effects on the nuclear shielding of a signal), the value found was
Fig. 3. ORTEP view of compound 2 (30% probability).

4074
M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
(31.3 ppm). The fact that the compound 5 has the lowest polari-
zation on the triple bond could be associated to a delocalized
electronic effect due to the presence of the C]C bond substituent.
This is supported by the charge alteration over the triple bond
It is also worth noticing that this average distance is smaller than
those observed in other tetranuclear rutheniumegold clusters con-
taining a m m3ePPh (3.002(6) Å) [33] even
3eSBut (2.950(1) Å) [32] or
though they have the same metal framework. Compounds 6 and 4
have larger Ru(1)eRu(2) distances (2.8534(9) and 2.8507(11) Å
respectively) than compounds 5, 3 and 2, [2.8331(6), 2.8416 av. and
2.8287(5) Å respectively]. Also, these bond distances are equal or
slightly shorter than the “normal” RueRu bond (2.854 Å av.) in
assumed to be evaluated by the
5 shows the largest value of all compounds. This fact could be
d
(Ca) þ
d(Cb) value, since compound
related to an electronic inductive effect of the substituents.
[Ru3(CO)12], while in the cluster [Ru3(CO)10(meCl)(meAuPPh3)] (1)
2.1. X-ray diffraction studies
the doubly bridged RueRu bond (2.8742(6) Å) being the largest of all
[13]. TheothertwoRueRudistances, Ru(2)eRu(3)andRu(3)eRu(1)[
2.8088 and 2.8070 Å av. respectively] are the shortest ones, which
could be related to a higher polarization in the coordinated acetylide
fragment as mentioned previously. The phosphine ligand is termi-
nallyattachedtothegoldatomwithaP(1)eAu(1)averagedistanceof
2.296Å. AlltheC(1)eC(2)distances(rangefrom 1.302(7)to 1.330(14)
Å) in the acetylide fragments are closer to a CeC double bond
distance (CspeCsp 1.21 Å; Csp2eCsp2 1.34 Å; Csp3eCsp3 1.53 Å [42])
reflecting the change in hybridization of these carbons upon
coordination.
Single crystal Xeray diffraction studies were carried out to
confirm the solid state structures of all synthesized compounds and
to verify that there were no important structural differences in the
described complexes. ORTEP diagrams of the structures are shown in
Figs. 3 to 7 and Table 2 collects some selected bond lengths and
angles. Compound 3 contains two crystallographically independent
molecules in the asymmetric unit; both are essentially identical and
only one of the two molecules is shown in Fig. 4. All compounds have
a “butterfly” metal framework array with the gold atom occupying
awingetip position. No significant differences in bond distances and
angles in compounds 2 to 6 and related complexes [Ru3(CO)9
The Ru(3)eC(1)eC(2) angles are in the range of 153.3(4) e
155.6(8)ꢁ, while the C(1)eC(2)eC(3) angles for compounds
2;141.0(5)ꢁ, 3;145.5(5)ꢁ and 143.5(5)ꢁ, 4;144.4(4)ꢁ and 5; 143.1(6)ꢁ
and C(1)eC(2)eSi(1) for 6;144.0(8)ꢁ; both groups of angles are
essentially the same than the corresponding values for [Ru3(CO)9
(
m
eAuPPh3)(
3eh2eteC^CFc)] [28] were observed. Similarly to compound
eAuPPh3)( eCl)] [13] and some other rutheniumegold
m
3eh2eteC^CBut)] [29],
[Ru3(CO)9(meAuPPh3)
(m
[Ru3(CO)10
(m
m
clusters [24,28,29] the AuPPh3 fragment is symmetrically coordi-
nated bridging the largest RueRu bond (Ru(1)eRu(2) ¼ 2.8415 Å av.).
(meAuPPh3)(m meH)
3eh2eteC^CBut)] [29] and [Ru3(CO)9(
Fig. 4. ORTEP view of compound 3 (30% probability).

M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
4075
(m
3eh2eteC^CR)] [8]. The trend observed in C(1)eC(2)eR angles
amount of chloroform and separated by TLC (eluent: hexanee-
among compounds 3(1) y 4 y 6 > 5 > 2 could be associated with
a decrease in size of the substituent. The dihedral angles formed by
the two planes [Ru(3)eRu(1)eRu(2) and Ru(1)eRu(2)eAu(1)] for the
heteronuclear butterfly core, are in the range of 110.30(2) to
121.28(1)ꢁ, with the SiMe3 substituted acetylide showing the lowest
value; this is probably due to its inherent hindrance properties. On
the other hand, the type of substituents on C(2) (Cb), does not affect
the interline angle between C(1)eC(2) and Ru(1)eRu(2) with an
average of 89.1ꢁ. No significant intermolecular short contacts were
found in any crystal packing of collected compounds.
chloroform (80:20 v/v).
4.3. [Ru3(CO)9(
m
eAuPPh3)(
m
3eh2eteC]CR)] (R ¼ C6H4e4eCH3)
(2)
The above procedure was employed for the preparation of 2. The
following compounds were used: [Ru3(CO)10 eCl)( eAuPPh3)] (1)
(m
m
(50.0 mg, 0.050 mmol), 1-etynyl-2-methylbenzene (16 mg;
0.111 mmol) and (CH3)3NO, (6 mg, 0.080 mmol). The first band was
identified as traces of starting material, the second band was iden-
tified as compound [Ru3(CO)9(meH)(m
3eh2eteC^CC6H4e4eCH3)]
Yield: (yellow solid, 4 mg,12%).1H NMR in CDCl3 at 298 K: 7.46 (d, 2H,
3. Conclusions
H(2,6), 3J ¼ 7.5 Hz), 7.16 (d, 2H, H(3,5), 3J ¼ 7.5 Hz), 2.38 (s, 3H,
CH3(40)), ꢀ20.51 (s, 1H, RueHeRu). IR
n(CO): 2097(w), 2073(m),
The study of tetraheteronuclear rutheniumegold clusters of
2053(m), 2022(vs), 1986(w) cmꢀ1. The sixth band corresponds to
general formula [Ru3(CO)9(meAuPPh3)(m
3eh2eteC^CR)] shows
compound [Ru3(CO)9(
(2). Yield: (yellow solid, 16 mg, 32%). HReMS (ESIeTOF); [MH]þ for
(CO):
meAuPPh3)(m
3eh2eteC^CC6H4e4eCH3)]
that change in the substituents on the terminal alkynes does not
significantly affect either the spectroscopic data or the main skeletal
fragments of these clusters in the solid state. However, the 13C NMR
data shows that there is some degree of polarization of the acetylide
CeC bondbeingthe lowest incompound 5, which could beassociated
to a delocalized electronic effect due to the unsaturated substituent.
The synthesis of this type of compounds is a clear example of the
ease of activation of C(sp)eH and C(sp)eC(sp) bonds in alkynes
promoted by a heterometallic rutheniumegold cluster, through the
rupture of the CeH bond and the reehybridization of the acetylenic
carbon atoms, establishing a simple synthetic route to this well-
eknown class of compounds.
On the other hand, the well known thermodynamically stability
of the Ru3(AuPPh3)(C2R) fragment was confirm since no decom-
position in solution or in the solid state were observed for all
compounds; this can be exploited, as mention before, in future
potential catalytic applications as hydrogenation or HDS processes.
(C36H23O9PRu3Au) calcd 1132.7870, found þ1132.7862. IR
n
2072 (m), 2053 (sh), 2033 (vs), 2004 (s), 1991 (sh), 1985 (s), 1959 (s),
1943 (sh) cmꢀ1. The remaining bands were not studied because they
did not contain coordinated ligands accordingly to their 1H NMR
spectrums.
4.4. [Ru3(CO)9(
(R ¼ C6H3e2,5e(CH3)2) (3)
meAuPPh3)(m
3eh2eteC^CR)]
The general procedure was employed for the preparation of 3. The
following compounds were used: [Ru3(CO)10 eCl)( eAuPPh3)] (1)
(50.0 mg, 0.050 mmol), 1-etynyl-2,5-dimethylbenzene (18
(m
m
ml;
4. Experimental section
4.1. General procedures and materials
All reactions were carried out under nitrogen atmosphere.
Solvents were dried prior to use by standard techniques and trime-
thylamine Neoxide dihydrate was sublimed several times in high-
vacuum to remove water. All chemicals were supplied by Aldrich
Company except chloro(triphenylphosphine)gold(I) which was
supplied by Strem Chemicals, all reagents were used without further
purifications. Commercial TLC plates (silica gel 60 F254) were used to
monitor the progress of the reactions. Infrared spectra for all
compounds were recorded in KBr pellets on a GX PERKIN Elmer 2000
FTeIR instrument. NMR spectra were measured on a JEOL Eclipse
400, JEOL GSX-270 and VARIAN 400 spectrometers in CDCl3, with 1H,
13C and 29Si spectra relative to SiMe4, and 31P spectra relative to 85%
aq. H3PO4. Mass spectra were recorded at CINVESTAVeMéxico
(HReLC1100/MSDTOFAgilentTechnologyequipment). Compound 1
was prepared accordingly to published procedure [26].
4.2. General procedure for the synthesis of compounds
[Ru3(CO)9(
m
eAuPPh3)(
m
3eh2eteC^CR)] (R ¼ C6H4e4eCH3 (2),
C6H3e2,5e(CH3)2 (3), C6H2e2,4,5e(CH3)3 (4), C(CH3)]CH2 (5),
Si(CH3)3) (6))
To the solution of [Ru3(CO)10(meCl)(meAuPPh3)] (1) was added
“in situ” an excess of the corresponding alkyne and 1.5 equivalent
amount of dry Trimethylamine Neoxide, (CH3)3NO. Every reaction
mixture was stirred for 2 h. The solvent was removed under low
pressure and the resulting residue was redissolved in a minimum
Fig. 5. ORTEP view of compound 4 (30% probability).

4076
M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
0.130 mmol) and (CH3)3NO, (6 mg, 0.080 mmol). The first band was
identified as traces of starting material, the second band was identified
band
3eh2eteC^CC6H2e2,4,5e(CH3)3)] (4). Yield: (yellow solid,
15 mg, 30%). HReMS (ESIeTOF); [MH]þ for (C38H27O9PRu3Au) calcd
corresponds
to
compound
[Ru3(CO)9(meAuPPh3)
(m
as compound [Ru3(CO)9(meH)(m
3eh2eteC^CC6H4e2,5e(CH3)2)]
Yield: (yellow solid, 3.2 mg, 9%).1H NMR in CDCl3 at 298 K: 7.26 (s,1H,
1160.8183, found þ1160.8191. IR
n(CO): 2069 (m), 2038 (sh), 2027
H(6)), 7.16 (d,1H, H(3), 3J¼ 7.7 Hz), 7.04 (d, 1H, H(4), 3J¼ 7.7Hz), 2.52(s,
(vs), 1998 (s), 1987 (s), 1978 (s), 1967 (m), 1961 (m) cmꢀ1. The
remaining bands were not studied because they did not contain
coordinated ligands accordingly to their 1H NMR spectrums.
3H, CH3(50)), 2.34 (s, 3H, CH3(20)), ꢀ20.37 (s,1H, RueHeRu). IR
n(CO):
2071 (m), 2052 (sh), 2030 (vs), 1990 (s, br), 1968 (sh), 1959 (sh) cmꢀ1
.
The fifth band corresponds to compound [Ru3(CO)9(
3eh2eteChCC6H4e2,5e(CH3)2)] (3). Yield: (yellow solid, 11 mg,
22%). HReMS (ESIeTOF); [MH]þ for (C37H25O9PRu3Au) calcd
meAuPPh3)
(m
4.6. [Ru3(CO)9(meAuPPh3)(m
(5)
3eh2eteC^CR)] (R ¼ C(CH3)]CH2
1146.8026, found þ1146.8028. IR
n(CO): 2071(m), 2030(vs), 1987(s,
br), 1961(sh) cmꢀ1. The remaining bands were not studied because
they did not contain coordinated ligands accordingly to their 1H NMR
spectrums.
The general procedure was employed for the preparation of 5.
The following compounds were used: [Ru3(CO)10 eCl)
eAuPPh3)] (1) (50.0 mg, 0.050 mmol), 2-methyl-1-buten-3-yne
(28 l; 0.300 mmol) and (CH3)3NO, (6 mg, 0.080 mmol). The first
band was identified as traces of starting material and the
second band corresponds to compound [Ru3(CO)9( eAuPPh3)
3eh2eteC^CC(CH3)]CH2)] (5). Yield: (yellow solid, 11 mg,
22%). HReMS (ESIeTOF); [MH]þ for (C32H21O9PRu3Au) calcd
1082.7713, found þ1082.7735. IR (CO): 2093 (m), 2069 (s), 2049
(sh), 2033 (vs), 1990 (vs, br), 1969 (m), 1963 (m), 1958 (m) cmꢀ1
(m
(m
m
4.5. [Ru3(CO)9(
(R ¼ C6H2e2,4,5e(CH3)3) (4)
meAuPPh3)(m
3eh2eteC^CR)]
m
(m
The general procedure was employed for the preparation of
4. The following compounds were used: [Ru3(CO)10 eCl)
eAuPPh3)] (1) (50.0 mg, 0.050 mmol), 1-etynyl-2,4,5-
trimethylbenzene (35 l; 0.276 mmol) and (CH3)3NO, (6 mg,
n
(m
.
(m
m
4.7. [Ru3(CO)9(
m
eAuPPh3)(
m
3eh2eteC^CR)] (R ¼ Si(CH3)3) (6))
0.080 mmol). The first band was identified as traces of
starting material, the second band was identified as
compound [Ru3(CO)9(meH)(m
3eh2eteC^CC6H4e2,4,5e(CH3)3)]
The general procedure was employed for the preparation of
6. The following compounds were used: [Ru3(CO)10 eCl)
eAuPPh3)] (1) (50.0 mg, 0.050 mmol), trimethylsilylacetilene
(42 l; 0.300 mmol) and (CH3)3NO, (6 mg, 0.080 mmol). The first
Yield: (yellow solid, 4.5 mg, 13%). 1H NMR in CDCl3 at 298 K: 7.19 (s,
1H, H(6)), 7.03 (s, 1H, H(3)), 3.73 (s, 3H, CH3(20)), 2.48 (s, 3H,
(m
(m
CH3(40)), 2.26 (s, 3H, CH3(50)), ꢀ20.37 (s, 1H, RueHeRu). IR
n
(CO):
m
2096(m), 2068 (vs), 2049(vs), 2013(vs), 1983(s) cmꢀ1. The fifth
band was identified as traces of starting material and the second
Fig. 6. ORTEP view of compound 5 (30% probability).
Fig. 7. ORTEP view of compound 6 (30% probability).

M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
4077
Table 2
Selected bond lengths (Å) and angles (ꢁ) for compounds 2e6.
Compound
2
3
4
5
6
Bond lengths
Ru(1)eRu(2)
Ru(2)eRu(3)
Ru(3)eRu(1)
C(1)eC(2)
C(2)eSi(1)
Molecule1
2.8448(6)
2.8138(6)
2.8088(6)
1.314(7)
e
Molecule2
2.8383(6)
2.8036(7)
2.7869(6)
1.313(6)
2.8287(5)
2.8103(5)
2.8269(6)
1.302(7)
e
2.8507(11)
2.8167(12)
2.7996(12)
1.330(14)
e
2.8331(6)
2.8023(7)
2.8100(7)
1.303(8)
e
2.8534(9)
2.8063(10)
2.8099(9)
1.330(13)
1.855(10)
e
C(2)eC(3)
Ru(1)eC(1)
Ru(1)eC(2)
Ru(2)eC(1)
Ru(2)eC(2)
Ru(3)eC(1)
Ru(1)eAu(1)
Ru(2)eAu81)
1.473(6)
2.185(5)
2.231(4)
2.190(5)
2.254(4)
1.947(5)
2.7652(4)
2.7645(4)
2.293(1)
1.461(7)
2.220(5)
2.246(5)
2.194(5)
2.277(5)
1.960(6)
2.7734(5)
2.7505(5)
2.295(2)
1.469(7)
2.197(5)
2.244(5)
2.182(5)
2.241(5)
1.941(5)
2.7739(5)
2.7684(5)
2.296(2)
1.444(13)
2.173(10)
2.264(10)
2.188(10)
2.249(10)
1.937(10)
2.7487(9)
2.7712(9)
2.296(2)
1.465(8)
2.202(6)
2.237(6)
2.192(6)
2.247(6)
1.950(6)
2.7597(5)
2.7616(5)
2.291(2)
2.190(9)
2.260(9)
2.169(9)
2.258(10)
1.938(9)
2.7659(7)
2.7590(7)
2.306(2)
Au(1)eP(1)
Bond angles
Ru(1)-Ru(2)-Ru(3)
Ru(2)eRu(3)eRu(1)
Ru(3)eRu(1)eRu(2)
Ru(3)eC(1)eC(2)
C(1)eC(2)eC(3)
60.172(13)
60.237(14)
59.592(12)
154.9(4)
141.0(5)
e
59.518(15)
60.791(15)
59.691(15)
153.3(4)
59.200(16)
61.021(16)
59.779(16)
153.5(4)
59.20(3)
61.00(3)
59.79(3)
155.4(8)
144.4(9)
e
59.817(17)
60.637(16)
59.546(16)
153.4(4)
143.1(6)
e
59.53(2)
61.07(2)
59.40(2)
155.6(8)
145.5(5)
143.5(5)
C(1)eC(2)eSi(1)
144.0(8)
104.6(3)
104.8(2)
105.9(2)
106.8(2)
C(2)eRu(1)eAu(1)
C(2)eRu(2)eAu(1)
C(1)eRu(1)eAu(1)
C(1)eRu(2)eAu(1)
Interline and interplane angles
C(1)eC(2)/Ru(1)eRu(2)
C(1)eC(2)/Ru(3)eRu(2)eRu(1)
Ru(3)eRu(1)eRu(2)/Ru(1)eRu(2)eAu(1)
C(1)eRu(1)eRu(2)/Ru(1)eRu(2)eAu(1)
C(2)eRu(1)eRu(2)/Ru(1)eRu(2)eAu(1)
104.44(12)
103.82(12)
108.00(11)
107.87(12)
101.11(14)
100.96(13)
107.92(13)
109.50(13)
101.26(13)
101.50(13)
108.17(13)
108.81(14)
101.5(2)
101.3(3)
108.3(3)
107.1(3)
102.89(15)
102.56(15)
108.28(15)
108.52(15)
89.5(2)
17.8(2)
114.32(1)
167.0(2)
148.2(1)
88.0(2)
17.2(3)
121.28(1)
174.6(2)
140.6(1)
89.6(3)
16.9(3)
119.83(1)
173.04(2)
141.6(1)
89.0(4)
17.5(4)
119.10(2)
172.0(3)
142.2(2)
89.3(3)
16.9(4)
117.15(2)
170.3(1)
144.9(2)
89.4(5)
18.4(5)
110.30(2)
163.1(3)
150.9(2)
Table 3
Crystal data and structure refinement parameters for compounds 2e6.
Compound
2
3
4
5
6
Empirical formula
Formula weight
Crystal colour and shape
Crystal system
Crystal size (mm)
Space group
C36 H22 Au1 O9 P1 Ru3 C37 H24 Au O9 P1 Ru3
C38 H26 Au1 O9 P1 Ru3
1157.73
red prism
C32 H20 Au1 O9 P1 Ru3
1079.63
orange plate
Monoclinic
C32 H24 Au1 O9 P1 Ru3 Si1
1111.75
orange prism
Monoclinic
1129.68
1143.71
red prism
Monoclinic
0.3 ꢂ 0.2 ꢂ 0.1
P21/c
orange prism
Monoclinic
0.28 ꢂ 0.11 ꢂ 0.1
P21/n
Monoclinic
0.25 ꢂ 0.21 ꢂ 0.15
0.41 ꢂ 0.39 ꢂ 0.21
0.25 ꢂ 0.19 ꢂ 0.091
C2/c
P21/n
P21
Unit cell dimensions
a (Å)
b (Å)
13.0243(2)
11.5864(2)
24.4145(4)
90.00
96.3720(10)
90.00
3661.50(10)
4
2.049
12.7175(3)
33.9779(8)
17.8827(4)
90
100.1460(10)
90
7606.5(3)
8
1.997
35.8213(11)
13.1804(5)
16.8224(5)
90.00
94.379(2)
90.00
7919.3(5)
8
1.942
13.2217(2)
17.0832(3)
16.0699(3)
90.00
107.9270(10)
90.00
3453.47(10)
4
2.076
12.3295(2)
10.1494(2)
15.1613(3)
90
102.2140(10)
90
1854.29(6)
2
1.991
c (Å)
a
b
g
(ꢁ)
(ꢁ)
(ꢁ)
V, (Å3)
Z
Dcalcd, (Mg mꢀ3
)
m
, (mmꢀ1
)
5.304
5.108
4.907
5.618
5.265
Temperature (K)
(Mo-K )) (Å)
Scan type
range (ꢁ)
Index ranges
293(2)
0.71073
293(2)
0.71073
293(2)
0.71073
293(2)
0.71073
293(2)
0.71073
uef
3.4 to 27.48
l
a
u
ꢀ
f
u
ef
u
ef
u
e
f
2
q
3.07 to 27.47
2.93 to 27.43
3.54 to 27.49
3.45 to 27.48
(hmin/hmax, kmin/kmax, lmin/lmax) ꢀ16/13, 13/15, ꢀ26/31 ꢀ16/13, 44/42, ꢀ22/23 ꢀ31/45, ꢀ15/17, ꢀ21/18 ꢀ17/16, ꢀ22/21, ꢀ20/20 ꢀ15/15, ꢀ13/11, ꢀ19/19
Reflections collected
Independent reflections
Observed reflections
Parameters/restrains
Rfinal; Rall data
22 163
41 476
18 593
37022
26051
8112 (Rint ¼ 0.0383)
16 544 (Rint ¼ 0.0479) 8232 (Rint ¼ 0.0635)
7878 (Rint ¼ 0.0393)
4430 (Rint ¼ 0.0393)
5855(F > 4
s
(F))
4352 (F > 4
s(F))
5558 (F > 4
436/0
0.0635, 0.1045
0.1547, 0.1860c
0.909
0.782/ꢀ1.067
s(F))
5695 (F > 4
s(F))
4021 (F > 4s(F))
452/0
923/0
416/1
391/1
0.0383, 0.0676
0.0761, 0.0881a
0.97
0.937/ꢀ0.826
0.0412, 0.0643
0.0855, 0.0744b
1.014
0.580/ꢀ0.746
0.0393, 0.0681
0.0793, 0.0681d
0.909
0.888/ꢀ1.148
0.0338, 0.0403
0.0792, 0.0824e
0.996
0.781/ꢀ1.292
Rwfinal, Rwall data
GOF (all data)
Max, min peaks (eÅꢀ3
)
a
wꢀ1
wꢀ1
wꢀ1
wꢀ1
wꢀ1
¼
¼
¼
¼
¼
s
s
s
s
s
2(F2o)þ(0.0400P)2 þ P.
b
c
2(F2o)þ(0.10.0062P)2 þ 5.5156P.
2(F2o)þ(0.1131P)2 þ 51.5217P.
d
e
2(F2o)þ(0.0322P)2 þ 4.6502P.
2(Fo2)þ(0.0485P)2 þ 1.2819P. Where P ¼ (Fo2þ2F2c)/3.

4078
M. HernándezeSandoval et al. / Journal of Organometallic Chemistry 696 (2011) 4070e4078
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band corresponds to compound [Ru3(CO)9(meAuPPh3)(m3eh
2eteChCSi(CH3)3))] (6). Yield: (yellow solid, 13 mg, 25%). HReMS
(ESIeTOF); [MH]þ for (C32H25O9PSiRu3Au) calcd 1114.7796,
found þ1114.7796. IR
n(CO): 2070 (m), 2040 (sh), 2029 (vs), 2004
(s), 1994 (sh), 1980 (s), 1971 (sh), 1960 (m), 1946 (m) cmꢀ1
.
5. Crystallography
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days. Table 3 shows details for data collection and structure
refinement for all compounds. Data were collected in an
EnrafeNonius Cappa CCD area detector diffractometer using MoK
a
radiation. The samples were mounted in MicroMounts (MiTeGen
company) www.mitegen.com. For all compounds, all non-
ehydrogen atoms were refined anisotropically. Hydrogen atoms
were fixed at idealized refined positions. Data collection, determi-
nation of unit Cell and integration of Frames of all compounds were
carried out using the suite Collect software [43] and HKL Scalepack
[44]. A semieempirical absorption correction method (SADABS)
[45] was applied in all cases. All structures were resolved by direct
methods, completed by subsequent difference Fourier synthesis,
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Acknowledgements
We gratefully acknowledge funding from Consejo Nacional de
Ciencia y Tecnología CONACYT, Mexico, (Grants No.: J110.362/2007,
CBe106849,
84453
and
025424)
and
PROM-
EPeUAEHGOePTCe265. MHS thanks CONACYT for her scholarship.
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