Dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes

Article abstract of DOI:10.1016/S0022-328X(00)00797-X

Reactions of the chloride-bridged dimers [LMCl(μ-Cl)]₂ (M=Rh, Ir; L=Cp=η⁵-C₅Me₅; M=Ru, L=η⁶-p-cymene) with two mole equivalents of thiosalicylic acid (HSC₆H₄CO₂H, H₂tsal) and excess base gives the dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes [LM(tsal)]₂. Reaction of the complex [Cp*RhCl₂(PPh₃)] with one equivalent of H₂tsal and triethylamine in dichloromethane gives a mixture of the dimer [Cp*Rh(tsal)]₂ and the phosphine complex [Cp*Rh(tsal)(PPh₃)]; upon recrystallisation, pure dimer is obtained. A single-crystal X-ray diffraction study on the rhodium and ruthenium dimers reveals the expected thiolate-bridged M₂(μ-S)₂ unit. Electrospray mass spectrometry (ESMS) is a useful technique in studying the chemistry of the thiosalicylate complexes, all complexes giving strong [M+H]⁺ ions. With added thiosalicylic acid, cations of the type [(LM)₂(Htsal)₃]⁺ were detected in the mass spectra.

Full text of DOI:10.1016/S0022-328X(00)00797-X

Journal of Organometallic Chemistry 625 (2001) 40–46
www.elsevier.nl/locate/jorganchem
Dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate
complexes
William Henderson a,*, Brian K. Nicholson a, Allen G. Oliver a,b, Clifton E.F. Rickard b
a Department of Chemistry, Uni6ersity of Waikato, Pri6ate Bag 3105, Hamilton, New Zealand
b Department of Chemistry, Uni6ersity of Auckland, Pri6ate Bag 92019, Auckland, New Zealand
Received 30 August 2000; received in revised form 16 October 2000; accepted 16 October 2000
Abstract
Reactions of the chloride-bridged dimers [LMCl(m-Cl)]2 (M=Rh, Ir; L=Cp*=h5-C5Me5; M=Ru, L=h6-p-cymene) with
two mole equivalents of thiosalicylic acid (HSC6H4CO2H, H2tsal) and excess base gives the dimeric rhodium(III), iridium(III) and
ruthenium(II) thiosalicylate complexes [LM(tsal)]2. Reaction of the complex [Cp*RhCl2(PPh3)] with one equivalent of H2tsal and
triethylamine in dichloromethane gives a mixture of the dimer [Cp*Rh(tsal)]2 and the phosphine complex [Cp*Rh(tsal)(PPh3)];
upon recrystallisation, pure dimer is obtained. A single-crystal X-ray diffraction study on the rhodium and ruthenium dimers
reveals the expected thiolate-bridged M2(m-S)2 unit. Electrospray mass spectrometry (ESMS) is a useful technique in studying the
chemistry of the thiosalicylate complexes, all complexes giving strong [M+H]+ ions. With added thiosalicylic acid, cations of the
type [(LM)2(Htsal)3]+ were detected in the mass spectra. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Rhodium; Ruthenium; Iridium; Thiosalicylate; Electrospray mass spectrometry; Crystal structures
1. Introduction
investigate the synthesis of other platinum-group metal
complexes with thiosalicylate ligands, and here report
our studies on p-hydrocarbon complexes of rhodium-
(III), iridium(III) and ruthenium(II).
There is interest in the coordination chemistry of
deprotonated thiosalicylic acid (H2tsal, 1), thiosalicy-
late, since the combination of hard carboxylate and soft
thiolate donors makes it potentially able to form com-
plexes with a wide range of metal centres. Recently, we
and others have reported complexes of platinum(II),
palladium(II) and nickel(II), [1–3] and gold(III) [4] in
which the thiosalicylate ligand bonds as an S,O-
chelated dianion. In addition, due to the bridging abil-
ity of thiolate ligands, the sulfur atom of platinum
complexes containing a chelated thiosalicylate ligand is
able to act as a donor ligand towards platinum(II) [2]
and mercury(II) [5], forming thiolate-bridged com-
pounds. In other complexes, thiosalicylate is able to
adopt a variety of coordination modes, ranging from
monodentate S-bonded [6], through to bridging [7,8].
As a result of this coordinative versatility, we wished to
Some ruthenium and rhodium thiosalicylate com-
plexes have been prepared previously, but as far as we
are aware, none have been characterised crystallograph-
ically. Rhodium(III) ions form a 1:2 complex with
thiosalicylic acid [9] while the dinuclear rhodium(II)
complex Rh2(Htsal)4(H2tsal)(H2O)·2.5H2O was pre-
pared by reaction of (NH4)3RhCl6 with H2tsal [10].
Reaction of this complex with HCl gave a material of
composition Rh(H2tsal)3Cl3, and other dinuclear
derivatives were also described. Other studies include
the reaction of [Ru(Hedta)(H2O)] (H4edta=ethylenedi-
amine tetraacetic acid) with thiosalicylic acid [11] and a
mixed thiosemicarbazone-thiosalicylate ruthenium com-
plex [12]. The related compound thiosalicylamide has
been used in the gravimetric and spectrophotometric
determination of rhodium, iridium and ruthenium [13].
We are unaware of any thiosalicylate complexes of
rhodium, iridium and ruthenium which also contain
organometallic ligands.
* Corresponding author. Tel.: +64-7-8562889; fax: +64-7-
8384219.
E-mail address: w.henderson@waikato.ac.nz (W. Henderson).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00797-X

W. Henderson et al. / Journal of Organometallic Chemistry 625 (2001) 40–46
41
2. Results and discussion
complex 4 showed an analogous Me 1H-NMR reso-
nance at l 1.25.
2.1. Synthesis and spectroscopic characterisation
Treatment of [Cp*RhCl(m-Cl)]2 with two mole equiv-
alents of thiosalicylic acid 1 in methanol, and triethyl-
amine base gives the dimeric rhodium complex 2.
Which is precipitated by addition of water as red,
air-stable crystals, which are soluble in dichloro-
methane and methanol but also have some water-solu-
bility, giving an orange solution. In a similar fashion,
reaction of the ruthenium complex [(h6-p-cymene)-
RuCl(m-Cl)]2 with thiosalicylic acid and triethyl-
amine in refluxing methanol gives the analogous com-
plex 3, which can be recovered in good yield as an
orange microcrystalline solid by precipitation with wa-
ter. The reaction with [Cp*IrCl(m-Cl)]2 proceeded simi-
larly, though the complex [Cp*Ir(tsal)]2 (4) could only
be recovered in low yield, as a bright yellow microcrys-
talline solid. The syntheses are summarised in Scheme
1. Complexes with M2S2 units formed by two bridging
thiolates have been reported previously for ruthenium,
e.g. from penicillamine [14] and other aliphatic thiols
[15] and for rhodium [16] including complexes of the
type [Cp*Rh(S–S)]2, where S–S is a bidentate dithio-
late ligand such as benzene-1,2-dithiolate [17], toluene-
3,4-dithiolate [18] or maleonitriledithiolate [19].
The 1H-NMR spectrum of 3 showed the expected
resonances due to the thiosalicylate ligand between l
8.08 and 7.20, together with four doublet resonances
for the cymene aromatic protons, with one pair [l 4.73
and 4.71] appearing as a strong AB doublet pattern due
to mutual coupling, and the other pair of doublets [l
5.04 and 4.57] showing approximately equal intensity
lines. There were also two doublet resonances due to
the cymene isopropyl methyl resonances, at l 1.10 and
0.81, but only one cymene methyl resonance at l 1.79.
The inequivalences of the cymene aromatic and isopro-
pyl methyl groups arise because the ruthenium centre is
unsymmetrical [20]. The rhodium complex 2 showed a
single resonance for the methyl groups of the Cp*
ligands, at l 1.22 (1H) and 8.3 (13C), and the iridium
The dimeric structures appear to have appreciable
stability towards cleavage of the thiolate bridges by
neutral ligands, since the reaction of the ruthenium
dimer 3 with a large excess of triphenylphosphine in
refluxing methanol resulted only in recovery of unre-
acted 3. Similarly no reaction was observed between 3
and excess CO after 5 days at room temperature, and
no thiosalicylate transfer was observed between 3 and
cis-[PtCl2(PPh3)2] after 3 weeks in methanol at room
temperature. When the complex [Cp*RhCl2(PPh3)] is
treated with one equivalent of thiosalicylic acid and
Et3N in dichloromethane at room temperature, a mix-
ture of 2 and the mononuclear complex [Cp*Rh(tsal)-
(PPh3)] (5) is obtained (as shown by ESMS), and on
recrystallisation from dichloromethane–pentane, the
dimer 2 was exclusively obtained. No further attempts
were made to prepare mononuclear thiosalicylate com-
plexes containing p-hydrocarbon ligands.
Scheme 1.

42
W. Henderson et al. / Journal of Organometallic Chemistry 625 (2001) 40–46
Fig. 1. Positive-ion electrospray mass spectra (in MeCN–H2O) of the ruthenium thiosalicylate complex [(p-cymene)Ru(tsal)]2 3 (‘dimer’) at cone
voltages of (a) 20 and (b) 80 V, showing the dimer to monomer fragmentation. The inset shows a comparison of experimental (left) and calculated
(right) isotope patterns for the [dimer+H]+ ion.
Complexes 2–4 give excellent ES mass spectra in
positive-ion mode. At low cone voltages (20–50 V) the
base peak is the [M+H]+ ion (Ru, m/z 777; Rh, m/z
781; Ir, m/z 959), with excellent agreement observed
between theoretical and calculated isotope distribution
patterns for these ions. Weak ions due to [2M+H]+,
[2M+Na]+, [2M+K]+ etc. were also observed, par-
ticularly for the iridium complex where the spectrum
was recorded in methanol. When the cone voltage is
increased to ca. 80 V, the dimeric species undergo
fragmentation to form the monomer, [Ru(tsal)(p-
cymene)+H]+, [Cp*Rh(tsal)+H]+ and [Cp*Ir(tsal)+
H]+ which are the base peaks at m/z 389, 391, and 481,
respectively. Fig. 1 shows the ES spectra for complex 3
at cone voltages of (a) 20 and (b) 80 V, showing the
dimer to monomer fragmentation. At 100 V, the Rh
complex also begins to undergo decarboxylation, as
shown by the formation of a low intensity ion at m/z
347; platinum thiosalicylate complexes have been found
to undergo the same behaviour at very high cone
voltages [1]. The rhodium complex 2 is slightly soluble
in water; after 2 weeks, the ES spectrum showed only
[2+H]+.
at 70 V and higher, fragmentation occurs, giving the
protonated bis-thiosalicylate species (2–4), together
with some of the monomer, as observed for 2–4 also.
Related ruthenium [(arene)Ru(m-EPh)3Ru(arene)]+
(arene=p-cymene or C6Me6; E=S, Se or Te) [21] and
rhodium and iridium [(Cp*M)(m-SR)3(MCp*)]+ [22]
cations have been reported previously.
ESMS has also been used to investigate the possibil-
ity of formation of mixed-metal thiosalicylate com-
plexes, by exchange reactions between 2 and 4, and
between 3 and 4. However, such reactions appear to be
slow in methanol solution at room temperature, with
only traces of the mixed metal Rh–Ir and Ru–Ir
species being observed on standing for 2 weeks. This
suggests that the dimeric structure is retained in solu-
tion, since dissociation to a monomeric species would
be expected to result in metal scrambling.
Addition of thiosalicylic acid to dilute solutions of
2–4 in MeCN–H2O followed by recording the positive-
ion ES spectra resulted in complete disappearance of
the [M+H]+ ions, and formation of single new ions
[Rh, m/z 935; Ru, m/z 931; Ir, m/z 1115] which are
identified from the mass and isotope patterns as the
tris(thiosalicylate) species [M+H2tsal+H]+ (M=2, 3
or 4). These species probably contain three thiosalicy-
late ligands, each bridging the two metal centres by
their thiolate sulfur atoms, with uncoordinated, proto-
nated carboxylic acid groups, i.e. 6. These species are
stable up to moderate cone voltages such as 50 V, but
Fig. 2. Molecular structure of [Cp*Rh(tsal)]2 (2) showing the atom
numbering scheme. Thermal displacement ellipsoids are depicted at
50% probability, and hydrogen atoms have been omitted for clarity.

W. Henderson et al. / Journal of Organometallic Chemistry 625 (2001) 40–46
43
ring, bonded through the thiolate sulfur and one of the
carboxylate oxygens. The thiolate sulfurs then bridge to
the other metal centres, forming the dimer containing a
M–S–M–S four-membered ring core.
As with other complexes containing chelating thiosal-
icylate ligands [1] the metal-thiosalicylate ring system of
2 is folded, predominantly at the rhodium and the
carboxylate, as seen from the obtuse Rh–O(1)–C(1)
bond angle of 133.1(2)°, with the carboxylate group
twisted by 31.4(5)° from the plane of the phenyl group.
The thiolate sulfur is unequally coordinated to the two
rhodium atoms, as seen in the different Rh–S bond
,
lengths [Rh–S 2.350(1) compared to Rh–S% 2.406(1) A].
These bond lengths are comparable with those in the
related complexes [Cp*Rh(S-S)]2 [S–S=maleoni-
Fig. 3. Molecular structure of [(p-cymene)Ru(tsal)]2 (3) showing the
atom numbering scheme. Thermal displacement ellipsoids are shown
at 50% probability, and all hydrogen atoms [except the isopropyl
hydrogens H(15a) and H(15a)%] have been omitted for clarity.
,
triledithiolate, 2.350(2) and 2.414(2) A [19]; S–S=ben-
,
zene-1,2-dithiolate, 2.356(1) and 2.401(1) A [17]]. A
similar asymmetric bridging coordination has been ob-
served for platinum thiosalicylate complexes coordi-
nated to platinum [2] or mercury [5]. The Rh–S–Rh%
bond angle of 97.32(3)° is comparable with that of the
manganese analogue 7 [Mn-S-Mn’ 96.56(4)°] [8], as are
the S–M–S% bond angles [82.68(3)° for S–Rh–S% com-
pared to 83.44(4)° for S–Mn–S%] and the O–M–S
bond angles [88.63(7)° for the rhodium complex and
88.2(7)° for the manganese analogue]. The M–S bonds
for both the rhodium and manganese complexes are,
surprisingly, identical [Rh–S 2.350(1) and Mn–S
Table 1
,
Selected bond lengths (A) and angles (°) for [Cp*Rh(tsal)]2 (2)
Rh–O(1)
Rh–C(14)
Rh–C(12)
Rh–S
2.084(2)
2.155(4)
2.173(4)
2.350(1)
1.778(4)
1.278(4)
1.511(5)
1.411(5)
1.380(5)
1.370(6)
Rh–C(13)
Rh–C(15)
Rh–C(11)
Rh–S%
2.144(4)
2.158(4)
2.186(4)
2.406(1)
2.406(1)
1.233(5)
1.407(5)
1.395(5)
1.379(6)
S–C(3)
S–Rh%
O(1)–C(1)
C(1)–C(2)
C(2)–C(7)
C(4)–C(5)
C(6)–C(7)
O(2)–C(1)
C(2)–C(3)
C(3)–C(4)
C(5)–C(6)
,
,
2.351(1) A; Rh–S% 2.406(1) and Mn–S% 2.406(1) A].
However, the M-O bonds for the two complexes differ
,
slightly [Rh–O 2.084(2) versus Mn–O 2.031(2) A]. The
O(1)–Rh–S
S–Rh–S%
C(3)–S–Rh%
C(1)–O(1)–Rh
O(2)–C(1)–C(2)
C(3)–C(2)–C(7)
C(7)–C(2)–C(1)
C(4)–C(3)–S
C(5)–C(4)–C(3)
C(7)–C(6)–C(5)
88.63(7)
82.68(3)
116.11(11)
133.1(2)
117.2(3)
117.8(3)
116.7(3)
115.0(3)
120.9(4)
120.2(4)
O(1)–Rh–S%
C(3)–S–Rh
Rh–S–Rh%
O(2)–C(1)–O(1)
O(1)–C(1)–C(2)
C(3)–C(2)–C(1)
C(4)–C(3)–C(2)
C(2)–C(3)–S
77.97(7)
103.82(12)
97.32(3)
121.3(4)
121.5(3)
125.4(3)
119.7(3)
125.3(3)
119.9(4)
121.5(4)
significant difference between these two complexes is
that the Mn complex is charged, while the Rh complex
is neutral.
Overall, the molecular geometry of the isoelectronic
ruthenium complex 3 is very similar to the rhodium
Table 2
C(4)–C(5)–C(6)
C(6)–C(7)–C(2)
,
Selected bond lengths (A) and angles (°) for [(p-cymene)Ru(tsal)]2 (3)
Ru–O(1)
Ru–C(10)
Ru–C(14)
Ru–C(9)
Ru–S%
2.0930(12)
2.1760(17)
2.2274(17)
2.2637(17)
2.4177(4)
2.4177(4)
1.230(2)
1.402(3)
1.406(2)
1.387(3)
Ru–C(11)
Ru–C(13)
Ru–C(12)
Ru–S
2.1648(17)
2.2187(17)
2.2313(17)
2.3848(4)
1.7831(18)
1.288(2)
1.513(3)
1.404(3)
1.387(3)
1.390(3)
2.2. Crystal structure determinations
S–C(3)
Single-crystal X-ray diffraction studies were carried
out on the dimeric rhodium and ruthenium complexes 2
and 3; the molecular structures are shown in Figs. 2
and 3, respectively. Selected bond lengths and angles
for the structures are given in Table 1 (2) and Table 2
(3). Both complexes have a distorted octahedral (‘bar-
stool’) metal coordination geometry, and overall pay a
strong resemblance to the formally isoelectronic dimeric
manganese(I) carbonyl complex 7, in which the p-hy-
drocarbon ligand is replaced by three CO ligands [8],
and to the related complexes [Cp*Rh(SC6H4S)]2 [17]
and [Cp*Rh{SC(CN)C(CN)S}]2 [19]. The thiosalicylate
ligand is coordinated such that it forms a six-membered
S–Ru%
O(1)–C(1)
C(1)–C(2)
C(2)–C(7)
C(4)–C(5)
C(6)–C(7)
O(2)–C(1)
C(2)–C(3)
C(3)–C(4)
C(5)–C(6)
O(1)–Ru–S
S–Ru–S%
C(3)–S–Ru%
C(1)–O(1)–Ru
O(2)–C(1)–C(2) 118.15(16)
C(3)–C(2)–C(1) 124.25(16)
C(7)–C(2)–C(1) 117.31(17)
87.80(4)
80.714(15) C(3)–S–Ru
112.48(6)
134.03(12)
O(1)–Ru–S’
77.80(4)
104.54(6)
99.286(15)
122.40(17)
119.32(15)
118.44(17)
119.80(17)
116.48(14)
Ru–S–Ru%
O(2)–C(1)–O(1)
O(1)–C(1)–C(2)
C(3)–C(2)–C(7)
C(2)–C(3)–C(4)
C(4)–C(3)–S
C(2)–C(3)–S
C(5)–C(4)–C(3) 120.57(19)
123.70(14)

44
W. Henderson et al. / Journal of Organometallic Chemistry 625 (2001) 40–46
complex 2, with comparable bond lengths. For exam-
[Cp*IrCl(m-Cl)]2 [26] were prepared according to the
literature procedures. Triphenylphosphine (Pressure
Chemical Co.), and thiosalicylic acid (Sigma) were used
as supplied. Reactions were carried out in LR grade
methanol without further purification, and without ex-
clusion of air. Petroleum spirits refers to the fraction of
boiling point 60–80°C, and was used as supplied, while
dichloromethane was distilled from calcium hydride
prior to use.
,
ple, the Ru–O(1) bond length [2.093(1) A] is similar to
,
the Rh–O(1) bond length [2.084(2) A]. The ruthenium
does not bond equidistantly to the p-hydrocarbon lig-
and, with the Ru–C bond lengths ranging from
,
,
2.165(2) A for Ru–C(11) to 2.264(4) A for Ru–C(9).
Steric interactions with the thiosalicylate ligand are the
likely cause of the longer Ru–C(9) bond. The ruthe-
nium lies almost directly under the centre of the cymene
ring.
The primary difference between the geometries of the
Rh and Ru complexes is the inclination angle of the
thiosalicylate ligand. With the plane of the p-hydrocar-
bon ligand as a reference, the angle of inclination of the
thiosalicylate phenyl ring can be determined. The incli-
nation angle for the Rh complex is 12.2(3)°, whereas for
the Ru complex it is much larger, at 23.1(1)°. This also
shows in the twisting of the carboxylate group from the
plane of the phenyl group, 41.7(3)° for the ruthenium
and 31.4(5)° for the rhodium complex. Steric interac-
tions between the p-hydrocarbon and thiosalicylate lig-
ands may be the cause of these differences, although the
intramolecular contacts between the atoms of either the
Cp* or p-cymene and thiosalicylate ligands are quite
3.2. Synthesis of [Cp*Rh(tsal)]2 (2)
A mixture of the complex [Cp*RhCl(m-Cl)]2 (300 mg,
0.484 mmol) and thiosalicylic acid (150 mg, 0.974
mmol) in methanol (7 ml) with triethylamine (10 drops,
excess) was refluxed for 10 min., giving a clear red–or-
ange solution. Water (70 ml) was added, giving red–or-
ange microcrystals. The mixture was allowed to stand
at room temperature (r.t.) for 3 days, and the product
filtered, washed with water (5 ml) and diethyl ether (5
ml) and dried in vacuo to give 2 as a red–orange
microcrystalline solid (220 mg, 58%). Crystals of suit-
able quality for an X-ray diffraction study were grown
by vapour diffusion of pentane into a dichloromethane
solution of the complex at 4°C. M.p.(dec.) \280°C.
Found: C, 51.5; H, 4.6. C34H38O4S2Rh2 requires C,
52.3; H, 4.9%. ESMS (positive-ion, MeCN–H2O, cone
voltage 20 V) [M+H]+ m/z 781 (100%); cone voltage
80 V, [Cp*Rh(tsal)+H]+ m/z 391 (100%), [M+H]+
,
long [closest contacts: Rh complex 3.362(7) A for
,
C(20)···C(2%) and Ru complex 3.435(4)
A
for
C(10)···C(3%)]. The p-cymene ligand of 3 may provide
less steric hindrance, as it only has two substituents
(Me and Pri) (in contrast to the fully substituted Cp*
ligand), allowing the thiosalicylate to fit into a pocket
of reduced steric interaction.
1
m/z 781 (70%). NMR: H, l 8.3–7.1 (m, 8H, Ph), 1.22
(s, 30H, Me); 13C-{1H}, l 170.1 (s, CO2), 138.8 (s, C of
Ph), 134.6 (s, CH of Ph), 134.4 (s, C of Ph), 133.6 (s,
CH of Ph), 128.6 (s, CH of Ph), 127.8 (s, CH of Ph),
Overall the conformation of the tsal2- ligand in these
complexes fits the pattern established for the nickel(II),
palladium(II) and platinum(II) complexes [2] which
showed that the ligand adapts readily to steric con-
straints by folding about the S···O atoms by varying the
M–O–C angle, and by twisting of the carboxylate
group from the plane of the rest of the ligand.
1
95.5 [d, C of Cp*, J(RhC) 7.0], 8.3 (s, Me of Cp*).
3.3. Synthesis of [(p-cymene)Ru(tsal)]2 (3)
[(p-cymene)RuCl(m-Cl)]2 (600 mg, 0.99 mmol) and
thiosalicylic acid (305 mg, 1.98 mmol) were suspended
in methanol (20 ml) and triethylamine (2 ml) added.
The resulting deep red solution was refluxed for 30 min.
Water (70 ml) was added and the mixture cooled to r.t.,
resulting in the deposition of orange microcrystals.
After standing for 2 days, the product was filtered,
washed with water (10 ml), petroleum spirits (10 ml)
and dried under vacuum, to give 627 mg of 2 (82%
yield). M.p.(dec.) \260°C. The product is soluble in
dichloromethane and chloroform, sparingly soluble in
diethyl ether, but insoluble in water. ESMS (positive-
ion, MeCN–H2O, cone voltage 20 V), [Ru(t-
sal)(cymene)+H]+ m/z 389 (8%), [M+H]+ m/z 777
(100%), [2M+H]+ m/z 1552 (5%). Cone voltage 80 V,
[Ru(tsal)(cymene)+H]+ m/z 389 (100%), [M+H]+ m/
3. Experimental
3.1. General experimental procedures
Electrospray mass spectra were recorded on a VG
Platform II instrument with nitrogen as the nebulising
and drying gas, and identification of ions was aided by
comparison of experimental and theoretical [23] isotope
distribution patterns. NMR spectra were recorded on a
Bruker AC300P instrument (1H, 300.133 MHz, 13C
75.47 MHz) in CDCl3, and IR spectra were recorded on
a Perkin–Elmer 1600 series instrument as KBr disks.
Melting points (m.p.s) were recorded using a Reichert–
Jung hotstage apparatus, and are uncorrected.
z 777 (50%), [2M+H]+ m/z 1552 (2%). NMR: H, l
1
The
complexes
[Cp*RhCl(m-Cl)]2
[24],
[(p-
8.08 [d, 1H, Ph of tsal, J(HH) 7.7], 7.62 [d, 1H, Ph of
tsal, J(HH) 7.7], 7.31 [t, 1H, Ph of tsal, J(HH) 7.5],
cymene)RuCl(m-Cl)]2 [25], [Cp*RhCl2(PPh3)] [24] and

W. Henderson et al. / Journal of Organometallic Chemistry 625 (2001) 40–46
45
Table 3
methanol (10 ml) with triethylamine (10 drops, excess)
was refluxed for 30 min, to give a cloudy yellow solu-
tion. Water (60 ml) was added, giving a clear yellow
solution, which on standing at r.t. for 1 week deposited
yellow microcrystals. These were filtered, washed with
water (10 ml) and petroleum spirits (10 ml) and dried in
vacuo. Yield 53 mg (15%). Found: C, 42.5; H, 3.9; N,
0.0. C34H39Ir2O4S2 requires C, 42.6; H, 4.0; N, 0.0%.
M.p.(dec.) \290°C. ESMS (MeOH, cone voltage 50
V), [M+H]+ (m/z 959, 100%), [M+Na]+ (m/z 981,
27%), [M+K]+ (m/z 997, 16%), [2M+Na]+ (m/z
Crystal data and structure refinement for [Cp*Rh(tsal)]2 (2) and
[(p-cymene)Ru(tsal)]2 (3)
2
3
Empirical formula
Formula weight
Crystal system
Space group
[3]Unit cell dimensions
C34H38O4Rh2S2
780.60
Monoclinic
P21/n
C34H36O4Ru2S2
774.89
Monoclinic
P21/c
,
a (A)
11.3821(2)
10.2707(2)
13.4726(2)
99.658(1)
1552.65(5)
4
9.6046(1)
12.8655(2)
12.4167(1)
105.819(1)
1476.20(3)
2
,
b (A)
,
c (A)
1
1941, 20%), [2M+K]+ (m/z 1957, 7%). H-NMR, l
i (°)
Volume (A )
Z
8.3–7.1 (m, 4H, Ph), 1.25 (s, 15H, Me of Cp*).
3
,
Density (calculated) (g
1.670
1.743
3.5. Reaction of [Cp*RhCl2(PPh3)] with thiosalicylic
acid
cm−3
)
Crystal size (mm)
q Range for data
collection (°)
0.28×0.20×0.07 0.40×0.18×0.07
2.17–28.21
2.20–28.21
To the rhodium complex (50 mg, 0.088 mmol) and
thiosalicylic acid (13.5 mg, 0.088 mmol) in
dichloromethane (5 ml) was added triethylamine (5
drops) and the mixture stirred at r.t. for 10 min to give
a red–orange solution. Petroleum spirits (60 ml) was
added, to give an orange precipitate, which was filtered
and dried, yield 35 mg. ESMS showed a mixture of
[Cp*Rh(tsal)]2 (2) and [Cp*Rh(tsal)(PPh3)] (5). Recrys-
tallisation from dichloromethane–pentane gave red
crystals of 2.
Reflections collected
Independent reflections
Absorption coefficient
9585
9217
3443 [Rint 0.0288] 3301 [Rint 0.0161]
1.235
1.204
(mm−1
)
Maximum transmission
Minimum transmission
F(000)
0.9186
0.7238
772
0.9205
0.6445
784
3301/0/194
1.029
Data/restraints/parameters 3443/0/195
Goodness-of-fit on F2
1.087
Final R indices [I\2|(I)]
R1
wR2
0.0340
0.0738
0.0186
0.0471
R indices (all data)
R1
wR2
3.6. Attempted reaction of 3 with PPh3
0.0508
0.0811 a
0.605
0.0221
0.0482 b
0.365
Largest difference peak
The ruthenium dimer 3 (100 mg) and triphenylphos-
phine (300 mg) in methanol (20 ml) was refluxed for 30
min to give an orange solution. Addition of water (60
ml) gave a light orange precipitate, which was allowed
to stand overnight, filtered, and the solid washed with
water (10 ml) and diethyl ether (2×20 ml) to remove
PPh3. The orange microcrystals (92 mg) were identified
as unreacted 2 by ESMS.
−3
,
(e A
)
Largest difference hole
−0.601
−0.380
−3
,
(e A
)
a w=1/[|2(Fo2)+(0.0299P)2+2.3859P] where P=(Fo2+2F2c)/3.
b w=1/[|2(Fo2)+(0.0245P)2+0.7557P] where P=(Fo2+2F2c)/3.
7.23 [t, 1H, Ph of tsal, J(HH) 7.7], 5.04 [d, 1H, CH of
cymene aromatic ring, J(HH) 5.9], 4.73 [d, AB pattern,
1H, CH of cymene aromatic ring, J(HH) 5.8], 4.71 [d,
AB pattern, 1H, CH of cymene aromatic ring, J(HH)
5.8], 2.51 [hept., 1H, CHMe2 of cymene, J(HH) 6.9],
1.79 [s, 3H, Me of cymene], 1.10 [d, 3H, CHMeA of
cymene, J(HH) 6.9], 0.81 [d, 3H, CHMeB of cymene,
J(HH) 6.9].
Crystals suitable for a single-crystal X-ray diffraction
study were obtained by diffusion of diethyl ether into a
dichloromethane solution of the complex at 4°C.
Found: C, 52.6; H, 4.65; N, 0.0. C34H36O4Ru2S2 re-
quires C, 52.7; H, 4.7; N, 0.0%
3.7. Exchange reactions
Approximately equimolar amounts (ca. 0.1 mg) of
complexes 2 and 4, and in a separate experiment, 3 and
4, were dissolved in methanol (1 ml), and the ES
spectrum recorded. The solutions were allowed to stand
at r.t. for 2 weeks and the extent of exchange deter-
mined from the ES spectrum.
3.8. X-ray crystal structure determinations
3.4. Synthesis of [Cp*Ir(tsal)]2 (4)
Data for both structures were collected on a Siemens
SMART CCD diffractometer, using Mo–Ka radiation
,
A mixture of [Cp*IrCl(m-Cl)]2 (300 mg, 0.377 mmol)
and thiosalicylic acid (116 mg, 0.753 mmol) in
(u=0.71073 A) at 203(2) K, and an absorption correc-
tion applied [27]. Both structures were solved by Patter-

46
W. Henderson et al. / Journal of Organometallic Chemistry 625 (2001) 40–46
son methods and refined routinely against F2 with
non-hydrogen atoms anisotropic and hydrogen atoms
included in calculated positions. Table 3 summarises
the data collection, solution and final refinement details
for both structures. The SHELX-97 suite of programs
were used [28].
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4. Supplematary material
Crystallographic data for the structures reported in
this paper have been deposited with the Cambridge
Crystallographic Data Centre, CCDC 150413 for com-
pound 2, and CCDC no. 150414 for compound 3.
Copies of this information may be obtained free of
charge from the Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (fax: +44-1223-336033;
e-mail:
deposit@ccdc.cam.ac.uk
or
http://
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Acknowledgements
We thank the University of Waikato for financial
support of this work, together with the New Zealand
Lottery Grants Board for a grant-in-aid for the pur-
chase of the mass spectrometer, and for the purchase of
precious metals. Wendy Jackson and Amu Upreti are
thanked for technical support.
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