Synthesis of carbido and related derivatives from calcium carbide and ruthenium carbonyl clusters

Article abstract of DOI:10.1039/b202364b

Reactions between a carbide anion (C₂^2- source and ruthenium cluster carbonyls are reported for the first time. The reaction between CaC₂ and Ru₃(CO)₁₂, carried out in thf, affords putative Ca[Ru₁₀(C)₂(CO)₂₄], which can be converted into [ppn]₂[Ru₁₀(C)₂(CO)₂₄] (1) in overall 60% yield. The X-ray structure of 1 as its 2CH₂Cl₂ solvate is described, together with those of the minor products Ru₄(μ₄-HC₂H)₂(μ-CO) ₂(CO)₉ (3), Ru₆C(μ₃-HC₂Me)(CO)₁₅ (4) and Ru₄(μ₄-CHCHCO)(μ-CO)(CO)₁₀(tmeda) (5). The latter contains an Ru-spiked Ru₃ core carrying a CHCHCO ligand; the tmeda chelates the spike Ru atom. The only product from Ru₃(μ-dppm)(CO)₁₀ and CaC₂ is the known compound Ru₆(μ₄-CCH₂)₂(μ-dppm) ₂(CO)₁₂ (16), formed in 24% yield.

Full text of DOI:10.1039/b202364b

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Synthesis of carbido and related derivatives from calcium carbide
and ruthenium carbonyl clusters
Michael I. Bruce,*a Natasha N. Zaitseva,a Brian W. Skeltonb and Allan H. Whiteb
a Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia.
E-mail: michael.bruce@adelaide.edu.au
b Department of Chemistry, University of Western Australia, Crawley, Western Australia 6009,
Australia
Received 6th March 2002, Accepted 25th July 2002
First published as an Advance Article on the web 13th September 2002
Reactions between a carbide anion (C22Ϫ) source and ruthenium cluster carbonyls are reported for the first time.
The reaction between CaC2 and Ru3(CO)12, carried out in thf, affords putative Ca[Ru10(C)2(CO)24], which can be
converted into [ppn]2[Ru10(C)2(CO)24] (1) in overall 60% yield. The X-ray structure of 1 as its 2CH2C12 solvate is
described, together with those of the minor products Ru4(µ4-HC2H)2(µ-CO)2(CO)9 (3), Ru6C(µ3-HC2Me)(CO)15 (4)
and Ru4(µ4-CHCHCO)(µ-CO)(CO)10(tmeda) (5). The latter contains an Ru-spiked Ru3 core carrying a CHCHCO
ligand; the tmeda chelates the spike Ru atom. The only product from Ru3(µ-dppm)(CO)10 and CaC2 is the known
compound Ru6(µ4-CCH2)2(µ-dppm)2(CO)12 (6), formed in 24% yield.
(CO)24]2Ϫ, which was first described in 1982 as the product from
Introduction
thermolysis (210–230 ЊC, 80 h) of [Ru6C(CO)16]2Ϫ in refluxing
tetraglyme.13 Several other products have been isolated from
the reaction mixture, but these are formed in low yields and
probably result from reactions of various cluster complexes
with ethyne formed from the calcium carbide reacting with
adventitious water.
The chemistry of metal cluster carbonyls containing carbido
ligands has a long history, the first complex, Fe5C(CO)15,
being discovered via an X-ray structural determination in
1962.1 These interesting compounds have usually been made
by pyrolysis of a simpler precursor carbonyl, the source of the
carbido atom being shown to be one of the carbonyl groups.2,3
In the ruthenium system, extensive studies have revealed several
intermediate clusters are formed en route from Ru3(CO)12 to
Ru6C(CO)17.4 The chemistry of carbido cluster complexes has
been reviewed.5
Other synthetic routes have been used to make cluster
carbides. For example, condensation of anionic Group 9 cluster
carbonyls with halocarbon derivatives results in formation of
complexes such as [Rh6C(CO)15]2Ϫ, from CCl4 and [Rh(CO)4]Ϫ,6
or [Co6C(CO)15]2Ϫ, from Co3(µ3-CCl)(CO)9 and [Co(CO)4]Ϫ.7
Results and discussion
When a 30-fold excess of solid calcium carbide (which is
approximately 80% pure) is added to a solution of Ru3(CO)12 in
thf and the mixture heated overnight, a dark-coloured solution
containing solid material is obtained. Removal of solvent and
filtration of an acetone extract of the residue into a solution of
[ppn]Cl in CH2Cl2 produces a dark purple solution, from
which the salt [ppn]2[Ru10(C)2(CO)24] (1) can be isolated in 60%
yield. We have not yet characterised any complexes from the
solid; based on the formulation Ca[Ru10C2(CO)24], the yield is
ca. 70%. The ν(CO) band frequencies in the IR spectrum are
similar to those reported earlier, while the 13C resonances of
the CO groups are found between δ 185 and 205 as five singlets,
the interstitial carbide giving a singlet at δ 456.89 (cf. δ 456 in
the [NEt4]ϩ salt). In the electrospray (ES) mass spectrum, the
doubly-charged parent anion is found at m/z 855.
Extensive hydrogenation of
a ruthenium cluster-bonded
ethynyl group has resulted in the addition of up to three H
atoms to one carbon of the C2 fragment, with a consequent
decrease in the C–C bond order. In the last stage, cleavage of
the C–C bond afforded a carbido complex, the second carbon
atom being fully reduced to a methyl group.8
Although several experimental procedures have now been
developed to produce carbido clusters in reasonable yield,9 to
the best of our knowledge, there are no reported uses of main
group carbides as sources of the carbido carbon atoms. This
may be because of (i) the relative difficulties attendant on the
production and manipulation of alkali metal acetylides, even
though Li2C2ؒen is available commercially, or (ii) reports that
in reactions with metal carbonyl halides, the acetylides tend to
act as one-electron reducing agents. For example, the reaction
of MnBr(CO)5 with CaC2 is reported to give Mn2(CO)10,
while Fe3(CO)12 and Co4(CO)12 give [Fe3(µ-H)(CO)11]Ϫ and
[Co6(CO)14]4Ϫ, respectively.10 In addition, {Re(CO) } (µ-C᎐C)
᎐
᎐
5
2
cannot be prepared from Re(FBF3)(CO)5 and Li2C2 or
Na2C2.11 Also relevant is the use of calcium carbide to form
transition metal carbides via metathesis reactions with halides
or oxides in the solid state, which has been reported recently.12
We have found that calcium carbide is a useful reagent for
the preparation of the anionic dicarbido cluster [Ru10(C)2-
DOI: 10.1039/b202364b
J. Chem. Soc., Dalton Trans., 2002, 3879–3885
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While the formation of 1 can result from thermolysis of
smaller ruthenium cluster carbides, we showed independently
that heating Ru3(CO)12 in thf overnight does not result in any
cluster condensation. Consequently, the formation of 1 is a
direct result of the interaction of CaC2 with the carbonyl, an
interesting and unusual cleavage of the C22Ϫ anion taking place.
Complex 1 was originally obtained by extended thermolysis
of the mono-carbido cluster [NEt4]2[Ru6C(CO)16]; it was noted
that the yield was dependent on the counter cation, only
decomposition resulting when Na, [ppn]ϩ or [NEt3(CH2Ph)]ϩ
were used.13 Fusion of two Ru6 clusters with concomitant
elimination of two Ru(CO)n fragments [or one Ru2(CO)y frag-
ment] had occurred.
µ3-η1:η1:η2 mode to one triangular face of the octahedral Ru6C
cluster, with bond parameters similar to those found for the
but-2-yne analogue.16 All the CO ligands are terminal, as found
in the solid-state structure, and give rise to ν(CO) bands
1
between 2088 and 1982 cmϪ1 in the IR spectrum. In the H
NMR spectrum, the Me and H protons of the alkyne resonate
at δ 1.67 and 6.97, respectively. We have described in an earlier
account the formation of Ru6(µ-H)(µ4-C)(µ4-CCMe)(µ-CO)-
(CO)16 (5) during the reaction between Ru3(CO)10(NCMe)2 and
ethyne.18 Disproportionation of two molecules of C2H2 to give
a carbide and propyne ligands occurred, and we suggest that a
similar reaction takes place here.
With a similar experiment carried out with only a 10-fold
excess of CaC2, the mother liquor from the separation of 1 was
evaporated and the residue extracted with dichloromethane.
Preparative t.l.c. enabled separation of several minor com-
ponents, three of which have been purified and characterised
initially by single-crystal X-ray crystallography as Ru4(µ4-HC2-
H)(CO)12 (2), Ru4(µ4-HC2H)2(µ-CO)2(CO)9 (3) and Ru6C(µ3-
HC2Me)(CO)15 (4). Subsequent assignments of their spectra
(IR, NMR, ES MS) on the bases of their solid-state structures
are discussed below. Complex 2 has been described before14 and
3 is the prototype for a series of substituted complexes M4(µ4-
RC2RЈ)2(CO)11 (M = Fe, R = H, RЈ = Et; M = Ru, R = Ph, RЈ =
Me, Ph) which have been reported earlier and which contain
two alkyne molecules attached to opposite sides of a buckled
M4 rhomb.15 It was characterised only by a single-crystal X-ray
structural determination, while the pattern of ν(CO) peaks in
its IR spectrum is similar to those reported for the substituted
analogues.
In an effort to facilitate the initial reaction between Ru3-
(CO)12 and CaC2, we added some tetramethyldiaminoethane
(tmeda) to the reaction mixture, hoping that the calcium cations
would be complexed by the diamine. As described in the
Experimental section, little change was observed in the form-
ation of 1, but among the minor products, the cluster Ru4(µ4-
CHCHCO)(µ-CO)(CO)10(tmeda) (6) was characterised. We
believe this to be the first example of a ruthenium cluster
containing the tmeda ligand.
The molecular structure of 6 is based on an Ru-spiked Ru3
triangle, which carries a CHCHCO ligand, formed by com-
bination of a CO ligand with an ethyne molecule (again, pre-
sumably formed from the CaC2). The chelating tmeda ligand is
attached to the Ru spike. Complex 6 contains the familiar allylic
ligand CHCHCOϪ which is closely related to that found
in Ru3(µ-H){µ3-CHCHC(OH)}(CO)8(PPh3).19 In the reactions
which lead to 6, deprotonation of the hydroxy group has
occurred and the resulting anion has become attached to the
fourth Ru atom. The origin of the latter is not clear at this
stage—one possibility is that an intermediate mononuclear
species, such as Ru(CO)3(tmeda), may be formed. The
proximity of the fourth Ru atom results in Ru–Ru bond form-
ation, giving the spiked cluster. The new bond is bridged by one
CO group, which gives rise to the ν(CO) band found at 1864
1
cmϪ1 in the IR spectrum. In the H NMR spectrum, the two
protons on the CHCHCO ligand give two doublets at δ 6.28
and 7.85, while those of the tmeda ligand occur at δ 3.14 (CH2),
and 2.37 and 2.60 (Me). Surprisingly, the oxo anion has not
attacked a CO, as found in the formation of Au3Ru3{µ3-OC-
(O)CPh2CHC}(CO)8(PPh3)3.20
We have also examined the reaction between CaC2 and
Ru3(µ-dppm)(CO)10, which often affords products different in
structure from those obtained from the parent carbonyl. In this
Complex 4 is a simple µ3-propyne complex of the hexa-
nuclear carbido carbonyl Ru6C(CO)17. A range of analogous
complexes, including the but-2-yne complex, has been described
by others.16,17 In 4, the propyne ligand is attached in the usual
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instance, the sole product that we have been able to characterise
is the hexanuclear vinylidene cluster Ru6(µ4-CCH2)2(µ-dppm)2-
(CO)12 (7), isolated in only 18–24% yield, which we earlier
obtained serendipitously and characterised as the benzene
solvate from the reaction of Ru3(µ-H)(µ3-C2SiMe3)(µ-dppm)-
(CO)7 with KF in MeOH.21 The present structure determin-
ation was carried out with a mixed CHCl3–MeCN solvate,
which showed considerable disorder (see Experimental section).
Molecular structures
Fig. 1–4 contain plots of the cation of 1 and molecules of 3, 4
and 6, respectively; significant bond parameters are given in
Tables 1–4.
Fig. 3 Plot of a molecule of Ru6C(µ3-HC2Me)(CO)15 (4).
Fig. 4 Plot of molecule 1 of Ru4(µ4-CHCHCO)(µ-CO)(CO)10(tmeda)
(6).
Table 1 Selected bond distances (Å) for [ppn]2[Ru10(C)2(µ-CO)4-
(CO)20] (1)a
Fig. 1 Plot of the anion in [ppn]2[Ru10(C)2(CO)24] (1), showing atom
numbering scheme.
Ru(1)–Ru(2)
Ru(4)–Ru(5)
Ru(3)–Ru(6)
Ru(1)–Ru(6)
Ru(2)–Ru(3)
Ru(3)–Ru(4)
Ru(5)–Ru(6)
Ru(1)–Ru(7)
Ru(2)–Ru(8)
Ru(4)–Ru(9)
Ru(5)–Ru(10)
Ru(1)–Ru(8)
Ru(2)–Ru(7)
2.9575(6)
2.9659(5)
2.8670(5)
2.9047(5)
2.8962(5)
2.8813(5)
2.9023(5)
2.9537(6)
3.0081(6)
2.9712(6)
2.9526(6)
2.8198(6)
2.8353(6)
Ru(4)–Ru(10)
Ru(5)–Ru(9)
Ru(3)–Ru(7)
Ru(3)–Ru(10)
Ru(6)–Ru(8)
Ru(6)–Ru(9)
Ru(3)–Ru(8)
Ru(3)–Ru(9)
Ru(6)–Ru(7)
Ru(6)–Ru(10)
Ru(7)–Ru(9)
Ru(8)–Ru(10)
2.8117(6)
2.8126(6)
2.8350(5)
2.8511(6)
2.8246(6)
2.8231(6)
3.1228(6)
3.1152(6)
3.0888(6)
3.1472(6)
3.2279(5)
3.1020(5)
a Ru–Ru bond distances have been grouped by type. Ru–C distances
2.025–2.102(5); C(1)–C(2) 3.015(5) Å.
In the structure of the anion in [ppn]2[1], very similar to but
more precisely defined than that found in [NEt4]2[Ru10(C)2-
(CO)24] ([NEt4]2[1]),13 the core comprises two octahedra sharing
an edge, one carbido atom being encapsulated in each. The
Ru–Ru separations form several sets. The shortest are those
bridged by CO ligands [2.8117–2.8353(6) Å], while Ru(3)–
Ru(6), at 2.8670(5) Å, is shared between the octahedra. Of the
non-bridged Ru–Ru vectors, those on the outside of the cluster
Fig. 2 Plot of a molecule of Ru4(µ4-HC2H)2(µ-CO)2(CO)9 (3). A
crystallographic mirror plane passes through Ru(2,3) and carbonyls 21,
31, 32 and the C(1,2) alkyne group.
J. Chem. Soc., Dalton Trans., 2002, 3879–3885
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are longer [2.9526–3.0081(6) Å] than the inner Ru(eq)–Ru(eq)
separations [2.8813–2.9047(6) Å]. Several Ru–Ru distances are
longer than 3 Å, ranging from Ru(2)–Ru(8) [3.0081(6) Å] to
Ru(6)–Ru(10) [3.1472(6) Å], while the separations between the
two pairs of apical Ru atoms are of the same order [Ru(7)–
Ru(9) 3.2279(5), Ru(8)–Ru(10) 3.1020(5) Å]. Of some interest
are the diagonal Ru(ap)–Ru(eq) distances involving atoms
Ru(3,6); both atoms are involved in short [2.8231–2.8511(6) Å]
and long interactions [3.1152–3.1472(6) Å], resulting in a
twist being imparted to the bioctahedral cluster [torsion
angles Ru(1,2,4,5) and Ru(2,1,5,4) Ϫ8.13 and Ϫ8.09(2)Њ]. The
C(1) ؒ ؒ ؒ C(2) separation is 3.015(5) Å. The two [ppn]ϩ cations
are bent, with N–P distances of 1.569–1.586(5) Å; P–N–P
141.7, 143.1(3)Њ.
Several reactions of 1 with unsaturated hydrocarbons have
given derivatives in which the apical Ru atoms are considered
to be either bonded or non-bonded.13,22 This feature has been
discussed previously in terms of the cluster valence electron
(c.v.e.) count for this anion (138 c.v.e.) and the occupation
of both bonding and anti-bonding MOs as the HOMOs.13,22
This c.v.e. count arises from the presence of two edge-sharing
octahedra, for which the Mingos procedure23 gives 2 × 86
(Ru6 octahedra) Ϫ 34 (Ru2 edge) = 138 c.v.e. It seems to us
that there is a continuum of Ru–Ru bonding interactions in all
these complexes, the relative separations of the bonding and
anti-bonding orbitals being determined by the electron density
within the cluster, which is, in turn, determined by the nature of
the other ligands present.
Of interest is the presence of two C atoms within the cluster,
rather than the initial C2 species present in the CaC2 precursor.
In closely related Group 9 carbido clusters, the presence of C or
C2 ligands has been related to the size of the cluster, the latter
required a (larger) trigonal prismatic cavity.24 However, the final
geometry is not a simple consequence of electron count.
26
In the isoelectronic [Rh12(C)2(CO)24]2Ϫ 25 and Rh12(C2)(CO)25
clusters, different cluster geometries are adopted as a result
of 2e in the former being replaced by the sterically more
demanding CO ligand in the neutral complex. In the present
case, the more electron-rich Ru atoms result in octahedral
cavities being formed, with resulting cleavage of the C–C bond.
Further discussion of the electronic structures of these and
related complexes is deferred until DFT studies have been
completed.
The molecule of 3 has a crystallographic plane of symmetry
passing through Ru(2,3)C(21,31,32) and the midpoint of
the C(3)–C(3Ј) vector. The four Ru atoms form a rhomb bent
along the Ru(1) ؒ ؒ ؒ Ru(1Ј) vector, with two different bonded
Ru–Ru distances: Ru(1)–Ru(2) [2.834(1) Å] and Ru(1)–Ru(3),
bridged by CO(13) [2.773(1) Å]. Angles subtended at one
Ru atom by the others are 85.25–87.57(5)Њ. The two ethyne
molecules lie on opposite sides of the Ru4 core, each being
attached by two σ [Ru(1)–C(3) 2.14(2), Ru(3)–C(2) 2.14(2) Å]
and two π [Ru–C 2.27–2.31(1) Å] bonds, the differences arising
because only Ru(2) is not attached to a µ-CO ligand. The C(1)–
C(2) separation is 1.39(3) Å. Unlike previous structurally
characterised examples which contain only one,15 3 contains
two bridging CO ligands. This cluster contains 62 c.v.e.
For 4, the octahedral Ru6C cluster has Ru–Ru separations
[2.9088–2.9905(4) Å] in the non-alkyne bridged faces and
internal Ru–C(carbide) distances [2.028–2.069(4), av. 2.05(1) Å]
which are similar to those found in the parent cluster27 and the
but-2-yne analogue.16 The Ru3 face [Ru(1,2,5)] supporting the
alkyne is slightly contracted [Ru–Ru 2.7718–2.8532(4) Å], as
is the opposite face [Ru(3,4,6): Ru–Ru 2.8547–2.8943(4) Å].
The Ru–C(alkyne) distances [Ru(1)–C(2) 2.059(4), Ru(5)–C(1)
2.046(4); Ru(2)–C(1,2) 2.189, 2.217(4) Å] are similar to those
found in Ru3(µ3-HC2Me)(µ-CO)(CO)9 and related Ru6C
clusters containing µ3-alkynes. The C(1)–C(2) separation is
1.400(6) Å and the bend-back angle for the Me substituent
is 56.0(3)Њ. All CO groups are terminal, a configuration that is
preserved in solution.
Comparison of the structure of 6 with that of Ru3(µ-H)-
{µ3-CHCHC(OH)}(CO)8(PPh3) (8)18 shows similar Ru–Ru
separations in the Ru3 triangle, with the exception of Ru(2)–
Ru(3) [2.8910, 2.8627(2) Å; values for molecules 1, 2 given],
which here is bridged by CO rather than by H as in 8. The
Ru(3)–Ru(4) distance is 2.8259, 2.8111(3) Å, and this vector
is bridged both by an η1-CO ligand and by the η2(C,O)-CO
portion of the CHCHCO ligand [Ru(3)–C(3) 2.030, 2.027(2),
Ru(4)–O(4) 2.075, 2.073(2) Å]. The tmeda ligand chelates
Table 2 Selected bond distances (Å) and angles (Њ) for Ru4(µ4–HC2-
H)2(µ-CO)2(CO)9 (3)a
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(1)–Ru(1Ј)
Ru(2)–Ru(3)
Ru(1)–C(1)
Ru(1)–C(2)
Ru(1)–C(3)
2.834(1)
2.773(1)
3.838(1)
3.843(1)
2.31(1)
2.27(1)
2.14(1)
Ru(2)–C(1)
Ru(2)–C(3)
Ru(3)–C(2)
Ru(3)–C(3)
C(1)–C(2)
C(3)–C(3Ј)
2.11(2)
2.31(1)
2.14(2)
2.28(1)
1.39(3)
1.37(2)
Ru(2)–Ru(1)–Ru(3)
Ru(1)–Ru(2)–Ru(1Ј)
Ru(1)–Ru(3)–Ru(1Ј)
86.53(4)
85.25(5)
87.57(5)
Ru(2)–C(1)–C(2)
Ru(3)–C(2)–C(1)
Ru(1)–C(3)–C(3Ј)
125(1)
126(1)
125.2(9)
a Primed atoms are related by the intramolecular plane.
Table 3 Selected bond distances (Å) for Ru6C(µ3-HC2Me)(CO)15 (4)a
Ru(1)–Ru(2)
Ru(1)–Ru(5)
Ru(2)–Ru(5)
Ru(1)–Ru(6)
Ru(2)–Ru(6)
Ru(3)–Ru(5)
Ru(4)–Ru(5)
Ru(3)–Ru(4)
Ru(3)–Ru(6)
Ru(4)–Ru(6)
2.8056(4)
2.8532(4)
2.7718(4)
2.9423(4)
2.9293(4)
2.9088(5)
2.9905(4)
2.8943(4)
2.8547(4)
2.8882(4)
Ru(2)–Ru(3)
Ru(1)–Ru(4)
2.9699(4)
2.9340(4)
Ru(1)–C(2)
Ru(2)–C(1)
Ru(2)–C(2)
Ru(5)–C(1)
2.059(4)
2.189(4)
2.217(4)
2.046(4)
C(1)–C(2)
C(2)–C(3)
1.400(6)
1.505(6)
a Ru–C(carbide) 2.028–2.069(4), av. 2.05(1) Å. C(1)–C(2)–C(3)
124.0(3)Њ.
Table 4 Selected bond parameters for Ru4(µ4-CHCHCO)(µ-CO)(CO)10(tmeda) (6; values for molecules 1, 2)
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(2)–Ru(3)
Ru(3)–Ru(4)
2.7699, 2.7656(3)
2.8613, 2.8702(3)
2.8910, 2.8627(2)
2.8259, 2.8111(3)
Ru(4)–O(4)
Ru(4)–N(5)
Ru(4)–N(6)
2.075, 2.073(2)
2.232, 2.230(2)
2.247, 2.250(2)
C(1)–C(2)
C(2)–C(3)
C(3)–O(4)
C(5)–N(5)
C(5)–C(6)
C(6)–N(6)
1.401, 1.401(3)
1.431, 1.435(3)
1.319, 1.312(2)
1.490, 1.487(3)
1.503, 1.499(3)
1.493, 1.483(3)
Ru(1)–C(1)
Ru(1)–C(2)
Ru(1)–C(3)
Ru(2)–C(1)
Ru(3)–C(3)
2.224, 2.235(2)
2.273, 2.286(2)
2.387, 2.383(2)
2.069, 2.089(3)
2.030, 2.027(3)
C(1)–C(2)–C(3)
C(2)–C(3)–O(4)
120.4, 119.8(3)
119.2, 119.8(2)
C(3)–O(4)–Ru(4)
N(5)–Ru(4)–N(6)
107.5, 107.9(1)
81.11, 81.68(7)
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Ru(4), with Ru(4)–N(5,6) 2.232, 2.230; 2.247, 2.250(2) Å and
an N(5)–Ru(4)–N(6) bite angle of 81.11, 81.68(7)Њ. The N
atoms are trans to the Ru–Ru bond and to CO(41) and the
tmeda takes up an envelope conformation. The geometry of the
CHCHCO fragment is similar to that found in 8, with C(1)–
C(2) 1.401, 1.401(3), C(2)–C(3) 1.431, 1.435(3) and C(3)–O(4)
1.319, 1.312(2) Å; the angles C(1)–C(2)–C(3) and C(2)–C(3)–
O(4) are 120.4, 119.8(3) and 119.2, 119.8(2)Њ, respectively.
Normal σ [Ru(2)–C(1) 2.069, 2.089(3); Ru(3)–C(3) 2.030,
2.027(2) Å] and π bonds [Ru(1)–C(1,2,3) 2.224–2.387(2) Å] are
found to the Ru3 triangle.
(4.8 mg, 5.3%), identified by comparison [IR ν(CO)] with an
authentic sample; (c) a yellow band (Rf 0.68) contained Ru4-
(µ4-HC2H)2(µ-CO)2(CO)9 (3) (1.1 mg, 1.0%), obtained as dark
yellow crystals (from CH2Cl2–pentane), identified by single-
crystal X-ray diffractometry. IR (cyclohexane): ν(CO) 2093w,
2063m, 2040s, 2030vs, 2019 (sh), 1985m, 1954vw, 1848w (br)
cmϪ1
.
Fraction B was also purified by t.l.c. (acetone–hexane 2:1) to
give a dark purple band (Rf 0.33), probably containing
[Ru10(C)2(CO)24]2Ϫas its solvated Ca2ϩ salt (43 mg). IR (thf ):
ν(CO) 2049vw, 2004vs, 1960w, 1930w cmϪ1. The compound is
moderately stable in air, both in solution and as a solid. It
was further characterised by conversion to the [ppn]ϩ salt by
dissolving 20 mg in acetone (5 ml) and adding [ppn]Cl (1.4 mg,
0.025 mmol). After stirring at r.t. for 30 min, evaporation and
extraction of the residue with CH2Cl2 and further purification
by preparative t.l.c. (acetone–hexane 2:1) gave [ppn]2[Ru10(C)2-
(CO)24] (1) (27 mg, 84%) as dark purple crystals (from CH2Cl2–
MeOH). Anal. found: C, 42.30; H, 2.04; N, 0.97; C98H60N2O24-
P4Ru10 calc.: C, 42.28; H, 2.17; N, 1.01%. IR (CH2Cl2): ν(CO)
2055vw, 2003vs, 1960w, 1927w, 1783m (br) cmϪ1 [cf. 2046w,
2003vs, 1962w (sh), 1922w (sh), 1798m cmϪ1 (thf )13a]. 1H NMR
(CDCl3): δ 7.24–7.623 (m, Ph). 13C NMR (CDCl3): δ 125.91–
133.59 (m, Ph), 185.40, 193.97, 202.36, 203.38, 205.29 (5 × s,
CO), 456.89 (s, C). 31P NMR (CDCl3): δ 22.33 (s, PPh3). ES MS
(C2H4Cl2, positive ion, m/z): 538, [ppn]ϩ; (negative ion, m/z):
855, [Ru10C2(CO)24]2Ϫ (isotopic peaks separated by 0.5 units).
A later experiment was carried out using Ru3(CO)12 (100 mg,
0.16 mmol) and CaC2 (300 mg, 4.7 mmol) in thf (20 ml) as
above, to give a dark brown solution over a dark coloured pre-
cipitate. The thf solution gave Ca[Ru10(C)2(CO)24] (9 mg), while
extraction of the precipitate with acetone gave the same com-
pound (46 mg). The combined product was dissolved in acetone
(5 ml) and [ppn]Cl (43 mg, 0.075 mmol) was added. After
30 min at r.t., evaporation and crystallisation of the residue
(CH2Cl2–MeOH) gave [ppn]2[Ru10(C)2(CO)24] (1) (75 mg, 57%)
as dark purple crystals.
Conclusion
We have shown for the first time that it is possible to use calcium
carbide as a source of carbido carbons in ruthenium clusters,
the major product from its reaction with Ru3(CO)12 being the
decanuclear dicarbido anion [Ru10(C)2(CO)24]2Ϫ. An unusual
feature of this reaction is the cleavage of the C22Ϫ anion present
in crystalline CaC2. Some minor products have also been
characterised: these contain ethyne or derived ligands and we
are inclined to suggest that these complexes are formed
from traces of ethyne present in the reaction mixture, possibly
generated by the reaction of CaC2 with water or another proton
source.
Experimental
General reaction conditions
Reactions were carried out under an atmosphere of nitrogen,
but no special precautions were taken to exclude oxygen during
work-up. Common solvents were dried and distilled under
nitrogen before use. Elemental analyses were performed by
Chemical and Micro-analytical Services p/l, Melbourne.
Preparative t.l.c. was carried out on glass plates (20 × 20 cm)
coated with silica gel (Merck 60 GF254, 0.5 mm thickness).
(b) With Ru3(CO)12 and tmeda. A similar reaction was carried
out between Ru3(CO)12 (150 mg, 0.24 mmol) and CaC2 (150 mg,
2.4 mmol) in thf (20 ml) containing tmeda (6 drops, ∼40 mg).
After removal of solvent, the residue was extracted with CH2Cl2
(fraction A) and acetone (fraction B). Separation of fraction A
by preparative t.l.c. (acetone–hexane 2:1) gave a major red band
(Rf 0.63) from which dark red crystals of Ru4(µ4-CHCHCO)-
(CO)11(tmeda) (6) (26 mg, 16.7%) were isolated. Anal. found: C,
27.11; H, 2.09; N, 3.25; C20H18N2O12Ru4 calc.: C, 27.75; H, 2.06;
N, 3.17%. IR (cyclohexane): ν(CO) 2075m, 2032s, 2022vs,
2007w, 1998w (br), 1993w (br), 1972w, 1959w, 1949w, 1864w
(br) cmϪ1. 1H NMR (CDCl3): δ 2.37, 2.60 (2 × s, 2 × 6H, Me),
3.14 (m, 4H, CH2), 6.28 [d, J(HH) 6.9, 1H, CH], 7.85 [d, J(HH)
6.9 Hz, 1 H, CH]. Other bands were separated but not
identified.
Instrumentation
IR: Perkin-Elmer 1720X FT IR. NMR: Bruker CXP300
orACP300 (1H at 300.13 MHz, 13C at 75.47 MHz) or Varian
Gemini 200 (1H at 199.8 MHz, 13C at 50.29 MHz) spectro-
meters. Unless otherwise stated, spectra were recorded using
solutions in CDC13 in 5 mm sample tubes. ES mass spectra: VG
Platform 2 or Finnigan LCQ. Solutions were directly infused
into the instrument. Chemical aids to ionisation were used as
required.28
Reagents
29
30
Ru3(CO)12 and Ru3(µ-dppm)(CO)10 were prepared accord-
ing to the cited methods. CaC2 (Aldrich) was a commercial
sample, used as received. It appeared to be about 80% pure, the
major impurity being Ca(OH)2.
Fraction B was purified by preparative t.l.c. (as above) to give
putative Ca[Ru10(C)2(CO)24] (41 mg, 33%).
Reactions of CaC2
(c) With Ru3(ꢀ-dppm)(CO)10. Tmeda (6 drops) was added to a
suspension of Ru3(µ-dppm)(CO)10 (100 mg, 0.1 mmol) and
CaC2 (64 mg, 1 mmol) in thf (10 ml). The mixture was heated
at reflux point overnight, after which the solvent was removed
and the residue was extracted with CH2Cl2. Separation by
preparative t.l.c. (acetone–hexane 3:7) afforded dark red Ru6-
(µ4-CCH2)2(µ-dppm)2(CO)12 (7) (22 mg, 24%), identified by
comparison (IR, NMR) with an authentic sample21 and also
by single-crystal X-ray structure determination of a disordered
CHCl3–MeCN solvate (the previous determination was carried
out with a C6H6 solvate). Several minor products were also
present but not characterised.
(a) With Ru3(CO)12. A suspension of Ru3(CO)12 (100 mg, 0.16
mmol) and CaC2 (100 mg, 1.6 mmol) in thf (20 ml) was heated
at reflux point overnight to give a brown solution above a
dark coloured precipitate. After removal of solvent (rotary
evaporator), the residue was extracted separately with CH2Cl2
(fraction A) and acetone (fraction B). Fraction A was separated
by preparative t.l.c. (hexane–acetone 7:3) to give several
coloured bands: (a) a brown band (Rf 0.74) contained Ru6C-
(µ3-HC2Me)(CO)15 (4) (2.3 mg, 2.7%), isolated as dark red
crystals (from CH2Cl2–MeOH). IR (cyclohexane): ν(CO)
2088w, 2062vw, 2043s, 2057m, 2022m, 2015m, 1994vw, 1982vw
cmϪ1. 1H NMR (CDCl3): δ 1.67 (s, 3H, Me), 6.97 (s, 1H, CH);
(b) a red band (Rf 0.71) yielded Ru4(µ4-HC2H)(CO)12 (2)
A similar reaction was carried out in the presence of Me3NO
instead of tmeda and produced 7 in 18% yield.
J. Chem. Soc., Dalton Trans., 2002, 3879–3885
3883

View Article Online
Structure determinations
the NMR spectra. The chloroform solvent is modelled in terms
of residues of occupancy 0.318(3), 1/2 Ϫ 0.318(3).
CCDC reference numbers 181260–181264.
See http://www.rsc.org/suppdata/dt/b2/b202364b/ for crystal-
lographic data in CIF or other electronic format.
Full spheres of data were measured at ca. 153 K using a Bruker
AXS CCD area-detector instrument. Ntotal data merging after
“empirical” /multiscan corrections (proprietary software) to N
unique (Rint quoted), No with F > 4σ(F) being used in the
refinements. All data were measured using monochromatic
Mo-Kα radiation, λ = 0.71073 Å. In the refinements, aniso-
tropic thermal parameter forms were used for the non-hydrogen
atoms, (Uiso)H being constrained at estimated values. Con-
ventional residuals R, Rw on |F| are quoted, statistical weights
being employed. Neutral atom complex scattering factors
were used; computation used the XTAL 3.7 program system.31
Pertinent results are given in the figures (which show non-
hydrogen atoms with 50% probability amplitude displacement
ellipsoids) and tables.
Acknowledgements
We thank the Australian Research Council for support of this
work and Johnson Matthey plc, Reading, UK, for a generous
loan of RuCl3ؒnH2O. We thank Professor B. K. Nicholson
(University of Waikato, Hamilton, New Zealand) for some
mass spectra.
References
Crystal and refinement data
1 E. H. Braye, L. F. Dahl, W. Hübel and D. L. Wampler, J. Am. Chem.
Soc., 1962, 84, 4633.
2 (a) C. R. Eady, B. F. G. Johnson and J. Lewis, J. Organomet. Chem.,
1972, 39, 329; (b) B. F. G. Johnson, J. Lewis, K. Wong and
M. McPartlin, J. Organomet. Chem., 1980, 185, C17.
3 (a) J. S. Bradley, G. B. Ansell and E. W. Hill, J. Am. Chem. Soc.,
1979, 101, 7417; (b) J. S. Bradley, G. B. Ansell and E. W. Hill,
J. Organomet. Chem., 1980, 184, C33.
4 (a) C. E. Anson, P. J. Bailey, G. Conole, B. F. G. Johnson, J. Lewis,
M. McPartlin and H. R. Powell, J. Chem. Soc., Chem. Commun.,
1989, 442; (b) P. J. Bailey, M. J. Duer, B. F. G. Johnson, J. Lewis,
G. Conole, M. McPartlin, H. R. Powell and C. E. Anson,
J. Organomet. Chem., 1990, 383, 441.
5 (a) M. Tachikawa and E. L. Muetterties, Prog. Inorg. Chem., 1981,
28, 203; (b) J. S. Bradley, Adv. Organomet. Chem., 1983, 22, 1;
(c) P. J. Dyson, Adv. Organomet. Chem., 1998, 43, 43.
6 V. G. Albano, P. Chini, S. Martinengo, D. J. A. McCaffrey,
D. Strumolo and B. T. Heaton, J. Am. Chem. Soc., 1974, 96, 8106.
7 V. G. Albano, P. Chini, S. Martinengo, M. Sansoni and D. Strumolo,
J. Chem. Soc., Chem. Commun., 1974, 299.
8 (a) C. J. Adams, M. I. Bruce, B. W. Skelton and A. H. White,
J. Chem. Soc., Chem. Commun., 1985, 744; (b) C. J. Adams,
M. I. Bruce, B. W. Skelton and A. H. White, J. Organomet. Chem.,
1989, 369, 393.
9 See, for example, Fe: (a) J. W. Kolis, M. A. Drezdzon and
D. F. Shriver, Inorg. Synth., 1989, 26, 246; (b) E. W. Hill and
J. S. Bradley, Inorg. Synth., 1990, 27, 182; Ru: (c) J. N. Nicholls
and M. D. Vargas, Inorg. Synth., 1989, 26, 280; (d) M. P. Cifuentes
and M. G. Humphrey, Inorg. Synth., 1998, 32, 287; Rh: (e) S.
Martinengo, D. Strumolo and P. Chini, Inorg. Synth., 1980, 20, 212.
10 M. C. Manning and W. C. Trogler, Inorg. Chim. Acta, 1981, 50, 247.
11 J. Heidrich, M. Steimann, M. Appel, W. Beck, J. R. Phillips and
W. C. Trogler, Organometallics, 1990, 9, 1296.
(1) [ppn]2[Ru10(C)2(CO)24]ؒ2CH2Cl2
≡
C98H60N2O24P4Ru10ؒ
¯
2CH2Cl2, M = 2954.0. Triclinic, space group P1, a = 12.313(1),
b = 18.211(2), c = 23.540(2) Å, α = 101.622(3), β = 94.226(3),
γ = 94.918(2)Њ, V = 5129 Å3, Dc (Z = 2) = 1.913 g cmϪ3. Crystal
0.32 × 0.30 × 0.13 mm, µ(Mo-Kα) = 1.7 mmϪ1, T min,max = 0.56,
0.73. 2θmax = 65Њ; Ntotal = 103731, N = 37560 (Rint = 0.044), No =
27340, R = 0.052, Rw = 0.073.
(3) Ru4(µ4-HC2H)2(µ-CO)2(CO)9 ≡ C15H4O11Ru4, M = 764.5.
Orthorhombic, space group Cmc21, a = 11.337(2), b = 13.456(2),
c = 12.805(2) Å, V = 1953 Å3, Dc (Z = 4) = 2.599 g cmϪ3. Crystal
0.30 × 0.10 × 0.08 mm, µ(Mo-Kα) = 3.1 mmϪ1, T min,max = 0.69,
0.86. 2θmax = 62.5Њ; Ntotal = 14802, N = 1733 (Rint = 0.051), No =
1631, R = 0.050, Rw = 0.107. xabs = 0.07(18).
(4) Ru6C(µ3-HC2Me)(CO)15 ≡ C19H4O15Ru6, M = 1078.7.
Monoclinic, space group C2/c, a = 16.9560(9), b = 9.4025(5),
c = 32.929(2) Å, β = 93.079(1)Њ, V = 5242 Å3, Dc (Z = 8) = 2.733 g
cmϪ3. Crystal 0.28 × 0.24 × 0.13 mm, µ(Mo-Kα) = 3.4 mmϪ1
,
T min,max = 0.58, 0.84. 2θmax = 75Њ; Ntotal = 52942, N = 13654
(Rint = 0.042), No = 11414, R = 0.038, Rw = 0.071.
(6) Ru4(µ4-CHCHCO)(µ-CO)(CO)10(tmeda)ؒ0.5CH2Cl2
≡
C20H18N2O12Ru4ؒ0.5CH2Cl2, M = 925.1. Triclinic, space group
¯
P1, a = 13.2174(6), b = 14.5234(9), c = 16.5710(7) Å, α =
73.859(1), β = 82.855(1), γ = 68.495(1)Њ, V = 2842 Å3, Dc (Z = 4)
= 2.162 g cmϪ3. Crystal 0.26 × 0.14 × 0.06 mm, µ(Mo-Kα) =
2.2 mmϪ1, T min,max = 0.60, 0.78. 2θmax = 75Њ; Ntotal = 59267, N =
29321 (Rint = 0.031), No = 20247, R = 0.031, Rw = 0.026. (x, y, z,
Uiso)H were refined.
12 A. M. Nartowski, I. P. Parkin, M. Mackenzie and A. J. Craven,
J. Mater. Chem., 2001, 11, 3116.
13 (a) C.-M. T. Hayward, J. R. Shapley, M. R. Churchill, C. Bueno
and A. L. Rheingold, J. Am. Chem. Soc., 1982, 104, 7347;
(b) M. R. Churchill, C. Bueno and A. L. Rheingold, J. Organomet.
Chem., 1990, 395, 85.
(7) Ru6(µ4-CCH2)2(µ-dppm)2(CO)12ؒ0.5CHCl3ؒ2MeCN
≡
C66H48O12P4Ru6ؒ0.5CHCl3ؒ2CH3CN, M = 1905.2. Triclinic,
¯
space group P1, a = 13.079(1), b = 15.254(1), c = 19.114(2) Å, α =
90.636(2), β = 99.454(2), γ = 105.195(2)Њ, V = 3624 Å3, Dc (Z = 2)
= 1.746 g cmϪ3. Crystal 0.49 × 0.36 × 0.30 mm, µ(Mo-Kα) =
1.42 mmϪ1, T min,max = 0.57, 0.80. 2θmax = 65Њ. Ntotal = 72818, N =
25430 (Rint = 0.035), No = 19208, R = 0.061, Rw = 0.113.
14 M. I. Bruce, B. W. Skelton, A. H. White and N. N. Zaitseva, J. Chem.
Soc., Dalton Trans., 1999, 1445.
15 M/R/RЈ = (a) Fe/H/Et: E. Sappa, A. Tiripicchio and M. Tiripicchio
Camellini, J. Chem. Soc., Dalton Trans., 1978, 419; (b) Ru/Me/Ph:
S. Aime, G. Nicola, D. Osella, A. M. Manotti Lanfredi and
A. Tiripicchio, Inorg. Chim. Acta, 1984, 85, 161; (c) Ru/Ph/Ph:
J. E. Davies, B. F. G. Johnson, C. M. Martion, R. H. H. Pearson and
P. J. Dyson, J. Organomet. Chem., 1998, 550, 431.
16 (a) S. R. Drake, B. F. G. Johnson and J. Lewis, J. Chem. Soc., Dalton
Trans., 1989, 243; (b) S. R. Drake, B. F. G. Johnson, J. Lewis,
G. Conole and M. McPartlin, J. Chem. Soc., Dalton Trans., 1990,
995; (c) R. L. Mallors, A. J. Blake, P. J. Dyson, B. F. G. Johnson and
S. Parsons, Organometallics, 1997, 16, 1668.
17 R. D. Adams and W. Wu, Organometallics, 1993, 12, 1238.
18 M. I. Bruce, B. W. Skelton, A. H. White and N. N. Zaitseva, J. Chem.
Soc., Dalton Trans., 1999, 13.
19 M. I. Bruce, N. N. Zaitseva, B. W. Skelton and A. H. White, J. Chem.
Soc., Dalton Trans., 1999, 2777.
Variata
(4) (x, y, z, Uiso)H were refined. (6) The dichloromethane was
modelled with the chlorine atoms disordered over two sets of
sites, occupancies set at 0.7 and complement after trial refine-
ment; (x, y, z, Uiso)H were refined. (7) Molecular parameters
determined from this structure are less precise than those of the
original determination, which was carried out on a tris-benzene
solvate, as a result of the presence of a disordered component,
which can be described in terms of the heavy atom component
being modelled as distributed over a pair of sites, population
ca 1:9, displaced on average by ca 0.5 Å. It is not possible to
define the light atom array associated with the minor com-
ponent, so that we cannot say whether the two molecules are
the same, one possibly displaced in concert with some com-
ponent of solvent disorder, or whether there is a second com-
ponent. However, we do not find any evidence for the latter in
20 M. I. Bruce, B. W. Skelton, A. H. White and N. N. Zaitseva, Inorg.
Chem. Commun., 1999, 2, 453.
21 M. I. Bruce, S. M. Pyke, N. N. Zaitseva, B. W. Skelton and
A. H. White, Helv. Chim. Acta, 2001, 84, 3197.
22 (a) L. Ma, D. P. S. Rodgers, S. R. Wilson and J. R. Shapley, Inorg.
3884
J. Chem. Soc., Dalton Trans., 2002, 3879–3885

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Chem., 1991, 30, 3591; (b) J. W. Benson, T. Ishida, K. Lee,
S. R. Wilson and J. R. Shapley, Organometallics, 1997, 16,
4929; (c) K. Lee and J. R. Shapley, Organometallics, 1998, 17,
4030; (d ) K. Lee and J. R. Shapley, Organometallics, 1998, 17,
4113; (e) K. Lee and J. R. Shapley, Organometallics, 1998, 17,
4368.
26 V. G. Albano, D. Braga, P. Chini, D. Strumolo and S. Martinengo,
J. Chem. Soc., Dalton Trans., 1983, 249.
27 (a) D. Braga, F. Grepioni, P. J. Dyson, B. F. G. Johnson, P. Frediani,
M. Bianchi and F. Piacenti, J. Chem. Soc., Dalton Trans., 1992, 2565;
(b) A. Sirigu, M. Bianchi and E. Benedetti, J. Chem. Soc., Chem.
Commun., 1969, 596.
28 W. Henderson, J. S. Mclndoe, B. K. Nicholson and P. J. Dyson,
J. Chem. Soc., Dalton Trans., 1998, 519.
23 (a) D. M. P. Mingos, J. Chem. Soc., Chem. Commun., 1983, 706;
(b) D. M. P. Mingos and A. S. May, in The Chemistry of Metal
Cluster Complexes, ed. D. F. Shriver, H. D. Kaesz, R. D. Adams,
VCH, New York, 1990, p. 89.
29 M. I. Bruce, C. M. Jensen and N. L. Jones, Inorg. Synth., 1989, 26,
259.
24 J.-F. Halet, in Topics in Physical Organometallic Chemistry,
ed. M. Gielen, Freund, London, 1992, vol. 4, pp. 221–288.
25 V. G. Albano, P. Chini, S. Martinengo, M. Sansoni and D. Strumolo,
J. Chem. Soc., Dalton Trans., 1978, 459.
30 M. I. Bruce, B. K. Nicholson and M. L. Williams, Inorg. Synth.,
1989, 26, 271.
31 S. R. Hall, D. J. du Boulay and R. Olthof-Hazekamp (eds), The Xtal
3.7 System, University of Western Australia, Crawley, 2002.
J. Chem. Soc., Dalton Trans., 2002, 3879–3885
3885