Reaction of ruthenium carbonyl chloride with iridium tetracarbonyl anion. Synthesis, crystal structure and characterisation of [Ru2Ir2H(CO)12Cl]: A heterometallic tetranuclear butterfly cluster with chloride bridge1

Article abstract of DOI:10.1016/S0022-328X(98)00703-7

Reaction between [Ru₂(CO)₆Cl₄] and Na[Ir(CO)₄] in tetrahydrofuran (THF) yielded [Ru₂Ir₂H(CO)₁₂Cl], a new iridium-ruthenium mixed-metal cluster of possible catalytic interest. The cluster was characterised by ¹H-NMR and infrared spectroscopy and by single-crystal X-ray structure analysis. [Ru₂Ir₂H(CO)₁₂Cl] exhibits a butterfly arrangement of metal atoms, with three terminal carbonyls on each metal atom, chloride ligand in the bridging position, and hydride ligand at the Ir-Ir edge. The trinuclear ruthenium cluster [Ru₃(μ-Cl)₂(CO)₈(PPhMe₂) ₂] was synthesised by reaction of [Ru₂(CO)₆Cl₄] with K[Ir(CO)₄] in THF, followed by ligand substitution with [PPhMe₂] in CH₂Cl₂ at ambient temperature. Determination of the structure by X-ray diffraction showed it to consist of an open trinuclear unit involving two metal-metal bonds. The open edge of the metal framework is supported by two symmetric bridging chloride ligands. Both phosphorus ligands are cis to the chlorine atoms and trans to the unique ruthenium atom.

Full text of DOI:10.1016/S0022-328X(98)00703-7

Journal of Organometallic Chemistry 573 (1999) 225–231
Reaction of ruthenium carbonyl chloride with iridium tetracarbonyl
anion. Synthesis, crystal structure and characterisation of
[Ru2Ir2H(CO)12Cl]: a heterometallic tetranuclear butterfly cluster with
chloride bridge1
Aapo U. Ha¨rko¨nen a, Markku Ahlgre´n a, Tapani A. Pakkanen a,*, Jouni Pursiainen b
a Department of Chemistry, Uni6ersity of Joensuu, PO Box 111, FIN-80101 Joensuu, Finland
b Department of Chemistry, Uni6ersity of Oulu, Linnanmaa, FIN-90571 Oulu, Finland
Received 4 April 1998
Abstract
Reaction between [Ru2(CO)6Cl4] and Na[Ir(CO)4] in tetrahydrofuran (THF) yielded [Ru2Ir2H(CO)12Cl], a new iridium–ruthe-
1
nium mixed-metal cluster of possible catalytic interest. The cluster was characterised by H-NMR and infrared spectroscopy and
by single-crystal X-ray structure analysis. [Ru2Ir2H(CO)12Cl] exhibits a butterfly arrangement of metal atoms, with three terminal
carbonyls on each metal atom, chloride ligand in the bridging position, and hydride ligand at the Ir–Ir edge. The trinuclear
ruthenium cluster [Ru3(v-Cl)2(CO)8(PPhMe2)2] was synthesised by reaction of [Ru2(CO)6Cl4] with K[Ir(CO)4] in THF, followed
by ligand substitution with [PPhMe2] in CH2Cl2 at ambient temperature. Determination of the structure by X-ray diffraction
showed it to consist of an open trinuclear unit involving two metal–metal bonds. The open edge of the metal framework is
supported by two symmetric bridging chloride ligands. Both phosphorus ligands are cis to the chlorine atoms and trans to the
unique ruthenium atom. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Ruthenium; Iridium; Cluster; Carbonyl; Crystal structure; Chlorine
now studied the reaction of [Ru2(CO)6Cl4] with
Na[Ir(CO)4] and K[Ir(CO)4].
1. Introduction
Reaction between [Ru2(CO)6Cl4] and Na[Ir(CO)4]
yielded a new mixed-metal cluster with a Ru2Ir2 frame.
Characterisation of the cluster by infrared and 1H-
NMR spectroscopy and X-ray diffraction analysis
showed it to be [Ru2Ir2H(CO)12Cl] (1), containing a
butterfly arrangement of the metal atoms with chlorine
bridging the two ruthenium ‘wings’.
Tetranuclear iron [5] and ruthenium [6] clusters are
known for forming butterfly structures, including
mixed-metal butterfly structures. Very few examples
exist, however, of opened tetranuclear butterfly clusters
Although much work has been done on tetranuclear
mixed-metal clusters of ruthenium, cobalt and rhodium
[1,2], there are only a few reports of closed tetranuclear
compounds containing a ruthenium and iridium mixed-
metal framework. The synthesis and characterisation of
a series of tetranuclear Ru3Ir and Ru2Ir2 clusters have
recently been described [3,4], but Ru2Ir2 frames are not
well known. In the context of our current interest in
synthesising and isolating mixed-metal clusters, we have
* Corresponding author. Fax: +358 13 2513344; e-mail:
Tapani.Pakkanen@Joensuu.FI
incorporating
ruthenium–iridium
heterometallic
1 Dedicated to Professor Brian Johnson on the occasion of his 60th
birthday in recognition of his outstanding contributions to
organometallic and inorganic chemistry.
frames. We have previously reported the synthesis and
structural characterisation of the chlorine bridged but-
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00703-7

226
A.U. Ha¨rko¨nen et al. / Journal of Organometallic Chemistry 573 (1999) 225–231
terfly Ru–Ir heterometallic cluster [Ru3IrH2(CO)12Cl]
[7], in which the chlorine atom is interacting with both
transition metals. Other Ru–Ir mixed-metal butterfly
structures described in the literature are [Ru3Ir(p5-
C5Me5)H4(CO)9] and [Ru3Ir(p5-C5Me5)H(CO)10BH2]
[8].
compound in the solution was characterised by 1H-
NMR spectroscopy and X-ray structure determination
as [Ru(CO)2Cl2(DMSO)2]. It is evidently formed by
decomposition of the starting material, [Ru(CO)3Cl2]2,
through reaction with the DMSO which was used as
solvent in the synthesis of K[Ir(CO)4]. This compound
was first synthesised in 1973, upon carbonylation of
cis-[RuCl2(DMSO)4] [11], and its structure has been
Reaction between [Ru2(CO)6Cl4] and K[Ir(CO)4] in
tetrahydrofuran (THF) gave products that were un-
stable towards chromatographic methods and they were
stabilised with PPhMe2 ligand. The products of reac-
tion were the new triruthenium cluster complex [Ru3(v-
Cl)2(CO)8(PPhMe2)2] (2) and the compound [Ru(CO)2
Cl2(DMSO)2], which was obtained by decomposition of
the starting material [Ru2(CO)6Cl4] through reaction
with the DMSO used as solvent. A phosphine-substi-
tuted triruthenium cluster structure similar to 2 has
been reported earlier [9,10]. Investigation of the struc-
ture of 2 by infrared and 1H-, 13C- and 31P-NMR
spectroscopy, elemental analysis and X-ray diffraction
analysis showed it to consist of a trinuclear open metal
framework with two metal–metal bonds.
1
described [12]. The H-NMR spectrum of [Ru(CO)2Cl2
(DMSO)2] in CDCl3 exhibits the SMe resonance at l
3.37 ppm.
2.3. Structure of [Ru2Ir2H(CO)12Cl] (1)
The crystal structure of 1 possesses a butterfly ar-
rangement of four metal atoms with chlorine atom
bridging the two ruthenium ‘wings’. Iridium atoms are
located on the hinge bond of the butterfly structure.
The structure is presented in Fig. 1, the bond distances
in Table 1, and selected bond angles in Table 2.
The structure of [Ru2Ir2H(CO)12Cl] is a wing-tip-
bridged 62-electron butterfly cluster with dihedral angle
of 93.5°. The value of the dihedral angle is comparable
to the values of 89.3 and 96.1° in the Ru3Ir and Ru3Co
clusters of the butterfly mixed-metal structures
[Ru3IrH2(CO)12Cl] [7] and [Ru3CoH(CO)12(SMe2)] [13].
All these values are typical for wing-tip-bridged 62-elec-
tron butterfly clusters [14].
A comparison of the chlorine bridging structures of 1
and [Ru3IrH2(CO)12Cl] shows the symmetry of the
metal skeletons of 1 and [Ru3IrH2(CO)12Cl] to be C2v
and CS, respectively. The higher symmetry in the metal
skeleton of 1 is the major factor in the higher molecular
symmetry (C2v) of the solid state of this compound. The
structure of 1 is similar to [Ru3IrH2(CO)12Cl] and pos-
sesses a pseudo mirror plane passing through the chlo-
ride ligand and the M(1) and M(2) atoms.
2. Results and discussion
2.1. Reaction of [Ru2(CO)6Cl4] with Na[Ir(CO)4]
The reaction of [Ru2(CO)6Cl4] with Na[Ir(CO)4] in
THF at room temperature led to the formation of
tetranuclear butterfly cluster [Ru2Ir2H(CO)12Cl] (1,
21%) and to an unidentified purple compound. The
residue that did not elute from the silica column was
extracted with THF as a brown solution. Attempts to
recrystallise the unidentified purple and brown com-
pounds failed.
2.2. Reaction of [Ru2(CO)6Cl4] with K[Ir(CO)4] with
addition of PPhMe2 ligand
The carbonyls in 1 are terminal, as in [Ru3Ir-
H2(CO)12Cl], whereas in [Ru3CoH(CO)12(SMe2)] the 11
carbonyl ligands are terminally coordinated to the
Ru3Co skeleton with one bridging carbonyl in the
hinge Co–Ru bond. Space-filling models [15] show that
steric pressure from the hydride ligands results in an
opening up of the M–M–CO angles along the Ir(1)–
Ir(2) edge. The Ir–Ir–CO angles are more obtuse in 1
(av. 113.1°) than analogues angles in [Ru3IrH2(CO)12Cl]
(av. 95.5°).
The wing metal–metal bonds in 1 are nearly equal,
whereas in [Ru3IrH2(CO)12Cl] the Ru–Ru bonds (298.9
pm) are clearly longer than the remaining metal–metal
bonds, which implies hydrogen-bridged bonds. For the
same reason the hinge Ir–Ir bond in 1 is longer (285.8
pm) than the Ru–Ir hinge bond in [Ru3IrH2(CO)12Cl]
(272.9 pm). Although there is no direct evidence for the
position of the cluster hydride, the position can never-
theless be derived indirectly. Accordingly bond dis-
The reaction between [Ru2(CO)6Cl4] and K[Ir(CO)4]
yielded products apparently unstable in chromato-
graphic processing and phosphine ligand was used to
stabilise them. [Ru2(CO)6Cl4] and K[Ir(CO)4] were al-
lowed to react in THF at ambient temperature for 1 h.
The residue was dissolved in CH2Cl2, and PPhMe2
ligand was added. The reaction led to the formation of
[Ru3(CO)12] and [Ru4H4(CO)12], and [Ru3(v-Cl)2(CO)8
(PPhMe2)2] (2) was isolated from the reaction mixture
in 11% yield. Contrary to the behaviour of Na[Ir(CO)4],
K[Ir(CO)4] does not participate in mixed-metal cluster
formation in this reaction. The role of the counter ion
is an interesting feature which can be used as directing
the synthesis. The reaction also yielded an unidentified
brown compound.
The residue that did not elute from the silica column
was extracted with THF as a brown solution. The

A.U. Ha¨rko¨nen et al. / Journal of Organometallic Chemistry 573 (1999) 225–231
227
Fig. 1. The molecular structure of [Ru2Ir2H(CO)12Cl] (1) with the atom labelling scheme. The hydrogen atom v2-bonded to the Ir–Ir edge was
not located by X-ray methods.
tances the hydride ligand in 1 lies on the Ir(1)–Ir(2)
hinge. Also the signal at −19.5 ppm in the NMR
spectrum indicates the hydride to be located at the
iridium–iridium metal edge. In the Ru(v2-H)Ir hydride
resonance in [Ru3IrH2(CO)12Cl] is at l −18.7 ppm.
The position of the hydride in 1 can be also identified
on the basis of the carbonyl conformations.
The Ru(1)–Cl–Ru(2) bridge angle (89.0°) is more
acute-angled than the corresponding angles in
[Ru3IrH2(CO)12Cl] but almost the same as in other
halogen-bridged compounds. For example, the metal–
The room temperature 1H-NMR spectrum of
[Ru2Ir2H(CO)12Cl] in CDCl3 solution exhibits one
sharp hydride resonance at l −19.5 ppm.
2.4. Structure of [Ru3(v-Cl)2(CO)8(PPhMe2)2] (2)
The structure of 2 consists of an open trinuclear unit
with two metal–metal bonds. The open edge of the
metal framework is supported by two symmetric bridg-
ing chloride ligands. The phosphorus ligands are coor-
dinated cis to the chlorine atoms and trans to the
unique ruthenium atom Ru(3). The overall geometry of
the molecule and the system used for labelling the
atoms are presented in Fig. 2. Selected interatomic
distances and bond angles are given in Table 3.
halogen–metal
bond
angles
are
88.3°
for
[PPN][Ru4(CO)13Cl] [16] and 87.9° for [Os4H3(CO)12I]
[17].
Table 1
Selected interatomic distances (pm) for [Ru2Ir2H(CO)12Cl] (1)
Table 2
Selected interatomic angles (°) for [Ru2Ir2H(CO)12Cl] (1)
Metal–metal
Ir(1)–Ru(1)
Ir(1)–Ru(2)
Ir(1)–Ir(2)
276.7(1)
276.5(1)
285.8(1)
Ir(2)–Ru(1)
Ir(2)–Ru(2)
276.2(1)
276.5(1)
Ru(1)–Cl–Ru(2)
89.0(1)
Cl–Ru(1)–Ir(1)
Cl–Ru(2)–Ir(1)
89.0(1)
89.3(1)
Cl–Ru(1)–Ir(2)
Cl–Ru(2)–Ir(2)
88.7(1)
88.8(1)
Metal–chlorine
Ru(1)–Cl
C(11)–Ir(1)–Ir(2)
C(12)–Ir(1)–Ir(2)
C(13)–Ir(1)–Ir(2)
C(11)–Ir(1)–Ru(1)
C(12)–Ir(1)–Ru(1) 168.1(5)
C(13)–Ir(1)–Ru(1) 80.0(4)
C(11)–Ir(1)–Ru(2) 172.3(4)
114.4(4)
111.8(5)
127.9(4)
96.2(4)
C(21)–Ir(2)–Ir(1)
C(22)–Ir(2)–Ir(1)
C(23)–Ir(2)–Ir(1)
C(21)–Ir(2)–Ru(1)
C(22)–Ir(2)–Ru(1) 171.4(5)
C(23)–Ir(2)–Ru(1) 85.1(4)
C(21)–Ir(2)–Ru(2) 168.5(5)
112.8(5)
113.4(5)
128.4(4)
91.7(4)
246.6(3)
Ru(2)–Cl
245.6(4)
Metal–carbon
Ir(1)–C(11)
Ir(1)–C(12)
Ir(1)–C(13)
Ir(2)–C(21)
Ir(2)–C(22)
Ir(2)–C(23)
189.0(2)
192.0(2)
184.9(1)
189.0(2)
191.0(2)
182.8(1)
Ru(1)–C(31)
Ru(1)–C(32)
Ru(1)–C(33)
Ru(2)–C(41)
Ru(2)–C(42)
Ru(2)–C(43)
179.0(2)
191.0(2)
188.0(2)
183.0(2)
191.0(2)
186.0(2)
C(12)–Ir(1)–Ru(2)
C(13)–Ir(1)–Ru(2)
91.7(5)
83.5(5)
C(22)–Ir(2)–Ru(2)
C(23)–Ir(2)–Ru(2)
95.5(5)
79.2(4)

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A.U. Ha¨rko¨nen et al. / Journal of Organometallic Chemistry 573 (1999) 225–231
Fig. 2. The molecular structure of [Ru3(v-Cl)2(CO)8(PPhMe2)2] (2) with the atom labelling scheme. The hydrogen atoms have been omitted for
clarity.
The distribution of carbonyl ligands in compound 2 is
in full agreement with the structural data reported for
[Ru3(v-Cl)2(CO)8(PPh3)2]. Carbonyl groups about Ru(1)
and Ru(2) adopt semi-axial positions which are trans to
the Cl atoms. The Cl–Ru–C values in 2 (average 174.1°)
The crystal structure of [Ru3(v-Cl)2(CO)8(PPhMe2)2]
is similar to the structure reported for [Ru3(v-
Cl)2(CO)8(PPh3)2] [10], which was prepared by pyrolysis
of [Ru3(v-AuPPh3)(v-Cl)(CO)10]. Both structures have
approximate C2v symmetry in the crystalline state, and
the Ru–Ru bond distances are almost the same:
285.1(1) and 286.0(1) pm for 2 and 284.5(1) and
286.0(1) pm for [Ru3(v-Cl)2(CO)8(PPh3)2]. The open
edge Ru–Ru distance is a little shorter in 2 than in
[Ru3(v-Cl)2(CO)8(PPh3)2] (318.0(1) pm vs 325.4(1) pm).
Other analogous compounds that include two bridge
atoms exhibit similar non-bonding distances: viz.
[Ru3(v-I)2(CO)10] (330.1(1) pm) [18] and [Ru3(v-
NO)2(CO)10] (315.0(1) pm) [19]. On this basis, it would
seem that the non-bonding ruthenium–ruthenium dis-
tance is influenced by the size of the bridging atom and
the steric hindrance of the ligand.
The ruthenium–chlorine bond distances in 2 are
248.9(1) and 249.4(2) pm for Ru(1)–Cl and 247.7(2)
and 249.3(2) pm for Ru(2)–Cl. The chlorine atoms are
thus nearly equidistant from the bridged ruthenium
atoms. The average Ru–Cl distance, 248.8 pm, is
slightly longer in 2 than in [Ru3(v-Cl)2(CO)8(PPh3)2]
(246.7 pm). Values of the Ru(1)–Cl–Ru(2) angles in
the structure of 2 are 79.6(1) and 79.2(1)°.
are
a little larger than the values in [Ru3(v-
Cl)2(CO)8(PPh3)2] (average 170.6°). The average value of
the Ru–C bonds trans to Cl (184.2 pm) is in fair
agreement with the structural data for [Ru3(v-
Cl)2(CO)8(PPh3)2] (181.6 pm). In both cases the metal–
carbon bonds are considerably shorter for Ru(1) and
Ru(2) than for the unique ruthenium atom: average 192.2
pm for 2 and 190.9 pm for [Ru3(v-Cl)2(CO)8(PPh3)2]. The
clearly shorter Ru–C bond distances are a consequence
of the trans position of Cl [20].
The phosphine ligands of 2 are bonded trans to the
Ru(3) atom and lie in almost equatorial sites. Substitu-
tion at these specific sites is typical of other analogous
clusters [21]. The 1H-NMR spectrum of complex 2
recorded in CDCl3 at room temperature shows reso-
nances at 7.4 and 1.7 ppm, which are the typical
resonances for free PPhMe2 ligand in CDCl3. According
to the 31P{1H}-NMR spectrum (signal at −7.2 ppm)
recorded under similar conditions, the two phosphine
ligands of 2 are equivalent in solution at ambient
temperature.

A.U. Ha¨rko¨nen et al. / Journal of Organometallic Chemistry 573 (1999) 225–231
229
Table 3
Selected interatomic distances (pm) and angles (°) for [Ru3(v-Cl)2(CO)8(PPhMe2)2] (2)
Ruthenium–ruthenium
Ru(1)–Ru(3)
Ru(1)…Ru(2)
285.1(1)
318.0(1)
Ru(2)–Ru(3)
286.0(1)
Ruthenium–chlorine
Ru(1)–Cl(1)
Ru(1)–Cl(2)
248.9(1)
249.4(2)
Ru(2)–Cl(1)
Ru(2)–Cl(2)
247.7(2)
249.3(2)
Ruthenium–phosphorus
Ru(1)–P(1)
236.6(2)
Ru(2)–P(2)
238.2(2)
Ruthenium–carbon
Ru(1)–C(11)
Ru(1)–C(12)
Ru(2)–C(21)
Ru(2)–C(22)
Ru(1)–Ru(3)–Ru(2)
Ru(1)–Cl(1)–Ru(2)
Angles involving Ru(1) atom
Cl(1)–Ru(1)–Ru(3)
Cl(2)–Ru(1)–Ru(3)
P(1)–Ru(1)–Ru(3)
C(11)–Ru(1)–Ru(3)
C(12)–Ru(1)–Ru(3)
About Ru(3) atom
C(31)–Ru(3)–Ru(1)
C(32)–Ru(3)–Ru(1)
C(32)–Ru(3)–Ru(2)
185.5(6)
183.4(6)
182.9(7)
185.0(6)
67.7(1)
Ru(3)–C(31)
Ru(3)–C(32)
Ru(3)–C(33)
Ru(3)–C(34)
191.1(6)
193.5(8)
191.1(6)
193.0(8)
79.6(1)
Ru(1)–Cl(2)–Ru(2)
Angles involving Ru(2) atom
Cl(1)–Ru(2)–Ru(3)
Cl(2)–Ru(2)–Ru(3)
P(2)–Ru(2)–Ru(3)
79.2(1)
88.3(1)
89.3(1)
177.6(1)
87.1(2)
87.6(2)
88.4(1)
89.1(1)
176.5(1)
85.5(2)
86.3(2)
C(21)–Ru(2)–Ru(3)
C(22)–Ru(2)–Ru(3)
95.2(2)
83.7(2)
84.0(2)
C(33)–Ru(3)–Ru(2)
C(34)–Ru(3)–Ru(1)
C(34)–Ru(3)–Ru(2)
98.8(2)
85.1(2)
83.5(2)
3. Conclusions
graphic separations were carried out under nitrogen
atmosphere using standard Schlenk techniques [24] and
with dried and deoxygenated solvents.
The reaction of [Ru2(CO)6Cl4] with [Ir(CO)4]− in
THF was fully characterised and found to give a new
tetranuclear mixed-metal cluster and other tetra-, tri-
and mononuclear ruthenium complexes. The new clus-
ter, [Ru2Ir2H(CO)12Cl], is the first example of a tetranu-
clear butterfly structure with Ru2Ir2 metal frame. In a
recent study [7], the Ru3Ir metal frame was shown to
form a wing-tip-bonded butterfly structure as well. In
general, tetranuclear clusters with three or four ruthe-
nium atoms form wing tip bonded butterfly clusters.
The present work demonstrates an extension of this
pattern to tetranuclear clusters with two rutheniums.
Iridium complexes, especially when promoted with
ruthenium, have been shown to catalyse carbonylation
of methanol [22]. Heterometallic butterfly cluster with
Pt2Ir2 frame has been found to be active in catalysed
homogeneous hydrogenation of olefins [23]. The
present work offers a new mixed-metal ruthenium–irid-
ium cluster for catalysis studies, where the metal com-
position and butterfly structure can be expected to have
an influence on the catalytic activity.
Infrared spectra were recorded in n-hexane or THF
on a Nicolet 20SXC FT–IR spectrometer. 1H-, 13C-
and 31P-NMR spectra were measured on a Bruker
AM-250 spectrometer with CDCl3 as solvent at 22°C.
The 1H-NMR spectra were referenced to external
Me4Si, the 13C-NMR spectra to CDCl3, and the 31P-
NMR spectra to external concentrated aqueous H3PO4.
Shifts to higher frequencies relative to the reference
were taken as positive. Crystals were grown by evapo-
ration of the solvent from a saturated hexane–CH2Cl2
solution.
4.2. Reagents
[Ru2(CO)6Cl4] was of commercial origin (Strem) and
was used without further purification. The phosphorus
ligand PPhMe2 was purchased from Aldrich Chemical.
K[Ir(CO)4] was prepared from [IrCl3] by a literature
method [25], and [IrCl3 x H2O] was of commercial
origin (Strem Chemicals). Na[Ir(CO)4] was prepared
from [Ir2(CO)6Cl2] by a literature method [25] and
[Ir2(CO)6Cl2] was of commercial origin (Strem).
THF (Merck) was dried and deoxygenated by stirring
over Na/benzophenone ketyl, and freshly distilled be-
fore use. Other solvents were dried by molecular sieves
and deoxygenated by bubbling N2 through them. KOH
was dried in an exsiccator.
4. Experimental details
4.1. General comments
All reactions and manipulations except chromato-

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A.U. Ha¨rko¨nen et al. / Journal of Organometallic Chemistry 573 (1999) 225–231
4.3. Preparation of [Ru2Ir2H(CO)12Cl] (1)
moved with hexane, and elution with a 3:1 mixture of
hexane–CH2Cl2 gave the title compound in 11%
yield. Further elution with CH2Cl2 gave an uniden-
tified brown fraction. The title compound was crys-
tallised from hexane–dichloromethane at 4°C. IR
(CH2Cl2): w(CO) 2075m, 2064w, 2050m, 2038sh,
2023s, 2005m and 1956w. 1H-NMR spectrum
(CDCl3): 7.4 (d, C6H5, 2JPH=6.8 Hz) and 1.7 (d,
CH3, 2JPH=9.4 Hz) ppm. 13C{1H}-NMR spectrum
(CDCl3): 130.4–129.3 (m, C6H5) and 31.6 (s, CH3)
ppm and 31P{1H}-NMR spectrum (CDCl3): −7.2
ppm. Anal. Calc. for C24H23Ru3O8Cl2: C, 32.96; H,
2.54. Found: C, 33.54; H, 2.50.
The compound [Ru2(CO)6Cl4] (83 mg, 0.16 mmol)
dissolved in 30 ml THF was mixed with a freshly
prepared solution of Na[Ir(CO)4] [26] (made from 86
mg, 0.28 mmol [Ir2(CO)6Cl2] in THF); the Ir/Ru mo-
lar ratio was approximately 1/2. The solution was
stirred at room temperature for 3 h. The reddish
brown solution was filtered and evaporated in vacuo
and the solid residue was treated with 85% H3PO4.
The residue was extracted with CH2Cl2 and gave a
red solution. After evaporation of the solvent in
vacuo (yielding 314 mg oily solid material), the
residue was chromatographed on a silica column (15
cm). Elution of the CH2Cl2 extract with hexane gave
a yellow band, which was not well eluted. The band
was successfully eluted with hexane–dichloromethane
(5:1) mixture. Further elution with pure CH2Cl2 gave
a weak purple band, which did not separate well be-
cause the compound decomposed in the column. The
yellow fraction was dried in vacuo and was then
identified as [Ru2Ir2H(CO)12Cl] (21 mg, 24%).
[Ru2Ir2H(CO)12Cl] was recrystallised from hexane–
dichloromethane at 4°C. Air-stable brown crystals
were formed. The infrared spectrum of 1 in n-hexane
shows bands at 2115w, 2088sh, 2077s, 2071s, 2061s,
2034m, 2022m, 2005w and 1993w cm−1 in the car-
The residue that did not elute from the silica
column was extracted with THF and gave brown so-
lution.
The
compound
was
identified
as
[Ru(CO)2Cl2(DMSO)2] by IR and NMR spectroscopy
and the identification was confirmed by X-ray diffrac-
tion. Air-stable brown crystals of [Ru(CO)2Cl2-
(DMSO)2] were obtained by slow diffusion of hexane/
CH2Cl2 solution at 4°C. IR data: w(CO) (CH2Cl2)
2084s, 2038sh and 2022vs cm−1 and w(SO) (CH2Cl2)
1133m cm−1. The latter signal was attributed to the
S–O stretch of an S-bonded Me2SO ligand. Free
Me2SO absorbs at 1050br cm−1 1H-NMR: (CDCl3,
.
293K) l 3.37 (s, CH3) and 2.56 (s, free DMSO)
ppm.
1
bonyl area. H-NMR: −19.5 (s) ppm.
The residue that failed to elute from the column
was extracted with THF. A brown solution was ob-
tained, from which the solvent was evaporated in
vacuo (yielding 142 mg oily solid material). Attempts
to crystallise the brown fraction failed. Its infrared
spectrum in THF exhibited w(CO) absorptions at
2134m, 2128sh, 2066sh, 2058s, 1996m and 1958w
4.5. Crystallographic summary
Pertinent crystal and refinement data are listed in
Table 4. Data were collected on a Nonius Kappa
CCD diffractometer for 1 and on a Nicolet R3m
diffractometer for 2 using Mo–Kh radiation (u=
cm−1
.
0.71073 A). Intensities were corrected for background,
˚
polarisation, and Lorentz factors [27] using DENZO
and SCALEPACK program package [27] for
1
4.4. Preparation of [Ru3(v-Cl)2(CO)8(PPhMe2)2] (2)
and SHELXTL program package [28] for 2. Apart
from scaling by SCALEPACK, no absorption
correction was applied for 1. Empirical absorption
correction from „-scan data for 2 did not improve
the result. The relatively high goodness-of-fit for
[Ir(CO)4]− was extracted with THF from the
KOH–DMSO mixture of the K[Ir(CO)4] synthesis
(initially 1.008 g, 3.38 mmol [IrCl3 x H2O]) [25] and
the extract was immediately added to a THF solution
of [Ru2(CO)6Cl4] (366 mg, 0.71 mmol). After stirring
at room temperature for 1 h, the solution was evapo-
rated under vacuum and the solid residue was treated
with 85% H3PO4. The residue was extracted with
CH2Cl2 and gave a reddish brown solution. A small
amount of water was added to the solution to eluted
residues of DMSO and the CH2Cl2 was evaporated in
vacuo (yielding 182 mg solid material).
2
was not found to depend on the weighting
scheme.
The metal atom positions were solved by direct
methods with use of the SHELXTL program package
[28]. All remaining non-hydrogen atoms were located
by the usual combination of full-matrix least-squares
refinement and difference electron density syntheses
using SHELXL93 [29]. Non-hydrogen atoms were
refined anisotropically refined for both structures. The
The solid was dissolved in CH2Cl2 (30 ml), and
PPhMe2 (12 vl) was added. After 1 h stirring at
room temperature the solution was chromatographed
on silica column. The majority impurities were re-
hydride atoms were placed in idealised positions (C–
2
˚
˚
H=0.93 A, U=0.08 A ) and not refined except the
hydride ligand in 1 which was excluded since it could
not be located from difference maps.

A.U. Ha¨rko¨nen et al. / Journal of Organometallic Chemistry 573 (1999) 225–231
231
References
Table 4
Summary of crystallographic data for compounds 1 and 2
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1
2
Empirical formula
C12HClO12Ru2Ir2 C24H22Cl2O8P2Ru3
Formula weight
Crystal system
Space group
a (pm)
b (pm)
c (pm)
959.1
874.5
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Orthorhombic
Pna21
1647.2(4)
748.6(2)
1642.7(4)
—
—
—
2.0256(9)
4
3.14
Monoclinic
P21/n
1403.9(3)
1213.1(2)
1832.6(4)
—
91.72(3)
—
3.1196(11)
4
.
h (°)
i (°)
k (°)
V (nm3)
Z
Dcalc. (g cm−3
)
1.88
1.72
1704
v(Mo–Kh) (mm−1
F(000)
)
15.5
1712
Crystal dimensions (mm)
Radiation
Monochromator
Scan range 2q, (°)
Number of reflections col-
lected
0.10×0.10×0.15 0.15×0.30×0.50
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Mo–Kh
Graphite
9–53
Mo–Kh
Graphite
5–55
18 055
6093
Number of unique reflections 3935
5828
5471
357
Number of observed data
Number of parameters
R[I\2|(I)]
3673
262
0.0321
0.0694b
1.009
1008
0.0342
0.0605c
0.779
454
wR(F2)a
Goodness of fit
Largest difference peak
(e nm−3
)
Largest difference hole
−1944
−376
(e nm−3
)
a Weight=
1/[|2(F20)+(aP)2+bP]
where
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1707.
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94306506.0, (1995).
P=[(F20)+2F2c]/3.
b a=0.03 and b=0.00.
c a=0.10 and b=0.00.
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Lippard (Ed.), Progress in Inorganic Chemistry, vol. 35, Wiley,
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Compounds, 2nd edn, Wiley, New York, 1986.
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Methods in Enzymology, vol. 276, Academic Press, New York,
1996, pp. 307–326.
[28] G.M. Sheldrick, SHELXTL-Plus; Release 4.11/v, Siemens Analyt-
ical X-ray Instruments Inc, Madison, WI, 1990.
[29] G.M. Sheldrick, SHELXL93. Program for the Refinement of
Crystal Structures, University of Go¨ttingen, Go¨ttingen, Germany,
1993.
The positions of all non-H atoms were found by
direct methods. Iterative application of least-squares
refinement and difference Fourier synthesis led to the
solution of the entire structure, including the H atoms.
All non-H atoms were refined anisotropically, while the
H atoms were freely refined using an isotropic model.
Crystallographic calculations were carried out using the
SHELXTL-Plus program package [28].
A complete list of bond lengths and angles and tables
of thermal parameters and hydrogen atom coordinates
has been deposited at the Cambridge Crystallographic
Data Centre.