A 2-iridathiophene from reaction between IrCl(CS)(PPh3) 2 and Hg(CH=CHPh)2

Article abstract of DOI:10.1016/j.jorganchem.2004.10.050

The thiocarbonyl analogue of Vaska's compound is produced in high yield by first treating IrCl(CO)(PPh₃)₂ with CS₂ and methyl triflate to give [Ir(κ²-C[S]SMe)Cl(CO)(PPh ₃)₂]CF₃SO₃ (1), secondly, reacting 1 with NaBH₄ to give IrHCl(C[S]SMe)(CO)(PPh₃)₂ (2), and finally heating 2 to induce elimination of both MeSH and CO to produce IrCl(CS)(PPh₃)₂ (3). When IrCl(CS)(PPh₃) ₂ is treated with Hg(CH=CHPh)₂ the novel 2-iridathiophene, Ir[SC₃H(Ph-3)(CH=CHPh-5)]HCl(PPh₃)₂ (4) is produced. The X-ray crystal structure of the iodo-derivative of 4, Ir[SC ₃H(Ph-3)(CH=CHPh-5)]HI(PPh₃)₂ (5) confirms the unusual 2-metallathiophene structure. Treatment of IrCl(CS)(PPh ₃)₂ with Hg(CH=CPh₂)₂ produces both a coordinatively unsaturated 1-iridaindene, Ir[C₈H ₅(Ph-3)]Cl(PPh₃)₂ (6) and a chelated dithiocarboxylate complex, Ir(κ²-S₂CCH=CPh ₂)Cl(CH=CPh₂)(PPh₃)₂ (7). X-ray crystal structure determinations for 6 and 7 are reported.

Full text of DOI:10.1016/j.jorganchem.2004.10.050

Journal of Organometallic Chemistry 690 (2005) 972–981
www.elsevier.com/locate/jorganchem
A 2-iridathiophene from reaction between IrCl(CS)(PPh3)2 and
Hg(CH@CHPh)2
*
Guo-Liang Lu, Warren R. Roper , L. James Wright , George R. Clark
*
Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand
Received 31 August 2004; accepted 20 October 2004
Abstract
The thiocarbonyl analogue of Vaskaꢀs compound is produced in high yield by first treating IrCl(CO)(PPh3)2 with CS2 and methyl
triflate to give [Ir(j2-C[S]SMe)Cl(CO)(PPh3)2]CF3SO3 (1), secondly, reacting 1 with NaBH4 to give IrHCl(C[S]SMe)(CO)(PPh3)2
(2), and finally heating 2 to induce elimination of both MeSH and CO to produce IrCl(CS)(PPh3)2 (3). When IrCl(CS)(PPh3)2 is
treated with Hg(CH@CHPh)2 the novel 2-iridathiophene, Ir[SC3H(Ph-3)(CH@CHPh-5)]HCl(PPh3)2 (4) is produced. The X-ray
crystal structure of the iodo-derivative of 4, Ir[SC3H(Ph-3)(CH@CHPh-5)]HI(PPh3)2 (5) confirms the unusual 2-metallathiophene
structure. Treatment of IrCl(CS)(PPh3)2 with Hg(CH@CPh2)2 produces both a coordinatively unsaturated 1-iridaindene,
Ir[C8H5(Ph-3)]Cl(PPh3)2 (6) and a chelated dithiocarboxylate complex, Ir(j2-S2CCH@CPh2)Cl(CH@CPh2)(PPh3)2 (7). X-ray crys-
tal structure determinations for 6 and 7 are reported.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Iridathiophene; Iridium; X-ray crystal structure; Thiocarbonyl ligand
1. Introduction
reaction. The first involves initial formation of an osma-
cyclobutenthione ring, from combination of CS with
one ethyne molecule, followed by ring expansion
through reaction with a second ethyne to give an osma-
cyclohexadienthione and finally aromatization of this
osmacyclohexadienthione through coordination of sul-
fur to osmium. There is precedent for the first step of
this pathway in that reaction between Os(CS)-
(CO)(PPh3)3 and diphenylacetylene produces a complex
with an osmacyclobutenthione ring [10]. The second
pathway would involve initial formation of an osmacy-
clopentadiene from combination of two ethyne mole-
cules on the osmium followed by ring expansion
through insertion of the thiocarbonyl ligand into this
five-membered ring. Either pathway depends for its
success on the readiness with which the thiocarbonyl
ligand undergoes insertion reactions. In related work,
we have demonstrated that the thiocarbonyl ligand will
insert into Os–H [11], Os–C [12], Os–Si [13], and Os–B
[14] bonds. With the exception of the Os–C example,
Since the report of the first metallabenzene in 1982
[1], this novel class of compounds has grown to include
stable examples incorporating all three third-row plati-
num group metals (Os [2], Ir [3], Pt [4]) as well as a fused
ring metalla-aromatic in the form of an iridanaphtha-
lene [5]. There are even examples of related isome-
tallabenzenes [6], metallabenzynes [7], and of other
metalla-heteroaromatic molecules, e.g., a group of irida-
thiophenes [8] and a group of metallafurans [9].
In the original osmabenzene synthesis, the OsC5 ring
was assembled from two ethyne molecules and a single
carbon atom from a thiocarbonyl ligand already resi-
dent on the osmium in the starting material, Os(CS)-
(CO)(PPh3)3. Two pathways can be envisaged for this
*
Corresponding authors. Tel: +64 9 373 7999x8320; fax: +64 9 373
7422.
E-mail address: w.roper@auckland.ac.nz (W.R. Roper).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.10.050

G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
973
insertion of a carbonyl ligand into these bonds, has not
been observed.
methylation occurs at the unbound sulfur and the meth-
yldithioester-containing cation is formed as the triflate
salt, [Ir(j2-C[S]SMe)Cl(CO)(PPh3)2]CF3SO3 (1). Com-
plex 1 is a pale yellow solid formed in almost quantita-
We have discovered that reaction between OsCl-
(NO)(PPh3)3 and Hg(CH@CHPh)2 leads, among other
products, to the hydrido 1-osmaindene complex,
Os(C8H6)H(NO)(PPh3)2, presumably through cyclomet-
allation of an introduced CH@CHPh ligand [15]. We
were therefore led to examine the reaction between
IrCl(CS)(PPh3)2 and Hg(CH@CHPh)2 in the expecta-
tion that any iridaindene formed might insert the thio-
carbonyl ligand thus producing an iridanaphthalene.
In fact, this did not happen but, nevertheless, unex-
pected and interesting products were formed.
tive yield. The IR spectrum shows m(CO) at 2038 cmꢀ1
.
1
In the H NMR spectrum, there is a signal at 2.19 ppm
associated with the dithioester methyl group and in the
13C NMR spectrum a signal at 30.7 ppm is also associ-
ated with this group. The iridium-bound carbon of the
dithioester group appears as a triplet at 239.7 ppm
(2JCP = 3.9 Hz) and the carbonyl carbon appears as a
triplet at 168.8 ppm (2JCP = 8.3 Hz). The mutually trans
arrangement of the two triphenylphosphine ligands is
indicated by the appearance of virtual triplet signals
for the carbons of these ligands and by the singlet reso-
nance in the 31P NMR spectrum at ꢀ2.50 ppm. Treat-
ment of this salt with sodium borohydride introduces
an hydride ligand so forming in high yield the neutral,
orange-pink, monodentate methyldithioester-containing
complex, IrHCl(C[S]SMe)(CO)(PPh3)2 (2). The IR spec-
trum of 2 shows m(CO) at 2036 cmꢀ1 and there is a
further medium absorption at 985 cmꢀ1 associated with
Herein, we report: (i) full experimental details for the
high-yield conversion of IrCl(CO)(PPh3)2 to IrCl(CS)-
(PPh3)2 (3) via the intermediates [Ir(j2-C[S]SMe)Cl(CO)-
(PPh3)2]CF3SO3 (1) and IrHCl(C[S]SMe)(CO)(PPh3)2
(2), (ii) the reaction of 3 with Hg(CH@CHPh)2 which
leads to the hydrido 2-iridathiophene, Ir[SC3H(Ph-3)
(CH@CHPh-5)]HCl(PPh3)2 (4), (iii) the conversion of
4 to the iodide analogue, Ir[SC3H(Ph-3)(CH@CH-
Ph-5)]HI(PPh3)2 (5), (iv) the reaction of 3 with
Hg(CH@CPh2)2 which leads to a mixture of the 1-irida-
indene, Ir[C8H5(Ph-3)]Cl(PPh3)2 (6) and the dithiocarb-
1
the monodentate dithioester function. In the H NMR
spectrum, there is a triplet signal at ꢀ11.91 ppm
(2JHP = 14.0 Hz) associated with the hydride ligand.
The triplet coupling indicates that the two triphenyl-
phosphine ligands remain mutually trans as depicted
to Scheme 1. In the 13C NMR spectrum, the methyl car-
bon resonance is at 20.8 ppm and the iridium-bound
carbon of the dithioester group appears as a broad sig-
nal at 288.7 ppm and the carbonyl carbon appears as a
triplet at 161.4 ppm (2JCP = 8.0 Hz). There is a singlet
resonance in the 31P NMR spectrum at ꢀ1.46 ppm.
Heating complex 2 in t-butanol results in the elimination
of MeSH and the loss of CO to give in quantitative
yield, the previously reported [17], orange, iridium(I)
thiocarbonyl complex, IrCl(CS)(PPh3)2 (3). The distinc-
tive m(CS) for 3 at 1332 cmꢀ1 and all other spectroscopic
features were concordant with literature values.
oxylate
CPh2)(PPh3)2 (7), and (iii) the crystal structure determi-
complex,
Ir(j2-S2CCH@CPh2)Cl(CH@
nations of complexes 5–7.
2. Results and discussion
2.1. High-yield conversion of IrCl(CO)(PPh3)2 to
IrCl(CS)(PPh3)2
As depicted in Scheme 1, and has been reported,
briefly, in an earlier publication [16], when IrCl(CO)
(PPh3)2 is dissolved in CS2 (so forming Ir(j2-CS2)
Cl(CO)(PPh3)2) and then treated with methyl triflate,
2.2. Reaction between IrCl(CS)(PPh3)2 and
Hg(CH@CHPh)2 leading to the hydrido-2-
iridathiophene, Ir[SC3H(Ph-3)(CH@CHPh-5)]
HCl(PPh3)2 (4), and the crystal structure of
Ir[SC3H(Ph-3)(CH@CHPh-5)]HI(PPh3)2 (5)
+
PPh3
Ir
PPh3
Ir
SMe
-
CS2/MeO3SCF3
OC
Cl
C
S
CF3SO3
Cl
CO
PPh3
PPh3
(1)
As shown in Scheme 2, complex 3 reacts rapidly with
Hg(CH@CHPh)2 in benzene under reflux with deposi-
tion of elemental mercury and formation, in high yield,
the green-black crystalline hydrido-2-iridathiophene,
Ir[SC3H(Ph-3)(CH@CHPh-5)]HCl(PPh3)2 (4). This for-
mula is written assuming the 2-metallathiophene struc-
ture with the numbers following the substituents Ph
and CH@CHPh indicating the ring positions of these
substituents (the numbering system is given in Chart
1). There is proof of this structure in the X-ray crystal
NaBH4
S
PPh3
PPh3
Ir
∆, tBuOH
OC
Cl
C
Ir
Cl
CS
SMe
H
-MeSH, -CO
PPh3
PPh3
(2)
(3)
Scheme 1. Synthesis of IrCl(CS)(PPh3)2 (3).

974
G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
There is precedent for the reaction of IrCl-
PPh3
Ir
*
PPh3
Ir
CS
PPh3
Ph
Ph
Hg(CH=CHPh)2
-Hg
(CO)(PPh3)2 with organomercury compounds, for
example, the reaction with Hg(C„CPh)2 leads to the
simple oxidative addition product, Ir[Hg(C„CPh)]-
(C„CPh)Cl(CO)(PPh3)2 [18]. This compound resists
thermal elimination of mercury. In the reaction se-
quence described in Scheme 2, involving IrCl(CS)-
(PPh3)2 rather than IrCl(CO)(PPh3)2, it is likely that
the initial product is also the oxidative addition product,
Ir[Hg (CH@CHPh)](CH@CHPh)Cl(CS)(PPh3)2, but
this must undergo further reactions, rapidly. One possi-
bility is that mercury is eliminated [19] to give com-
pound A in Scheme 2 which in turn undergoes rapid
migratory insertion of the CS ligand to give compound
B [12]. b-Hydrogen elimination from B would give both
PhC„CH (perhaps retained in the coordination sphere)
and the Ir–H bond observed in the product 4. Combina-
tion of the PhC„CH with the j2-vinylthioacyl ligand in
B could lead to the observed product Ir[SC3H(Ph-3)-
(CH@CHPh-5)]HCl(PPh3)2 (4). Other pathways can be
envisaged but whatever steps occur the overall reaction
is clean and high yielding.
Cl
CS
Cl
PPh3
(A)
(3)
Ph
Ph
*
PPh3
Ir
PPh3
Ir
Ph
H
C
S
H
Cl
Cl
S
PPh3
(B)
PPh3
Ph
(4)
NaI
PPh3
Ir
Ph
H
H
I
S
PPh3
Ph
(5)
Scheme 2. Reaction between IrCl(CS)(PPh3)2 and Hg(CH@CHPh)2.
*Compounds A and B are postulated intermediates, not characterised.
The IR spectrum of 4 shows m(IrH) at 2195 cmꢀ1. In
the 1H NMR spectrum, there is a triplet signal at ꢀ11.11
ppm (2JHP = 14.0 Hz) associated with the hydride li-
gand. The triplet coupling indicates that the two triphe-
nylphosphine ligands remain mutually trans as depicted
in Scheme 2. In the 13C NMR spectrum, the 2-iridathi-
ophene ring carbons appear at 222.9 (C3), 144.9 (C4),
and 209.8 (C5) ppm (following the ring numbering sys-
tem given in Chart 1). The low-field resonance for C3 is
consistent with a carbene-like character for the Ir–C
bond. These chemical shifts correspond closely with
the values found for Bleekeꢀs related iridathiophene
complexes depicted in Chart 1 where the ring carbons
have been renumbered from the original publications
to match the numbering scheme we are using. For the
structure determination of the iodide derivative of 4
(compound 5) to be described below. Related iridathi-
ophene complexes have been described previously from
introduction to iridium of the thiapentadienide ion and
subsequent systematic modification of this ligand
[8a,8b]. That the same ring system is assembled in the
work described in this paper from a CS ligand and
two styryl fragments is testimony to the stability of this
aromatic metallacycle. Remarkably, the iridathiophene
described by Bleeke could be treated with excess bro-
mine, without damaging the ring, to bring about electro-
philic substitution (bromination) of the iridathiophene
(see compound depicted in Chart 1) [8b].
Ph
3
Ph
3
PPh3
PPh3
H
H
H
I
H
I
4
4
2
Ir
2
Ir
S
S
5
5
1
1
PPh3
PPh3
Ph
Ph
(C)
(D)
Me
3
Me
3
PEt3
PEt3
Br
H
H
H
Br
Br
I
I
4
4
2
Ir
2
Ir
S
S
5
5
1
1
PEt3
PEt3
Bleeke's iridathiophene, ref. 8b
Bleeke's ring brominated
iridathiophene, ref. 8b
Chart 1. Ring numbering scheme and valence bond structures for the new 2-iridathiophene, Ir[SC3H(Ph-3)(CH@CHPh-5)]HI(PPh3)2 (5), and other
related iridathiophenes.

G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
975
non-brominated iridathiophene, the C3, C4 and C5
chemical shifts are 235.3, 150.3 and 205.1 ppm, respec-
tively, and for the brominated iridathiophene the corre-
sponding chemical shifts are 222.4, 129.2 and 201.5 ppm
[8b].
Crystals of 4 suitable for X-ray study could not be
obtained. However, the lability of the chloride ligand
allowed replacement of the chloride by iodide forming
Ir[SC3H(Ph-3)(CH@CHPh-5)]HI(PPh3)2 (5) and suit-
able crystals of 5 were easily obtained. The spectro-
scopic properties of 5 are closely similar to those of
4. The IR spectrum of 5 shows m(IrH) at 2221 cmꢀ1
Fig. 1. The molecular geometry and atomic numbering scheme for
Ir[SC3H(Ph-3)(CH@CHPh-5)]HI(PPh3)2 (5) (for clarity, phenyl rings
on the triphenylphosphine ligands are not shown). N.B. the crystal-
lographic numbering scheme differs from that given in Chart 1.
1
and in the H NMR spectrum there is a triplet signal
at ꢀ11.95 ppm (2JHP = 16.0 Hz) associated with the hy-
dride ligand. In the 13C NMR spectrum, the 2-iridathi-
ophene ring carbons appear at 225.0 (C3), 144.6 (C4),
and 211.7 (C5) ppm (following the ring numbering sys-
tem given in Chart 1). The molecular geometry of 5 is
shown in Fig. 1. Crystal data pertaining to this struc-
ture and other structures reported in this paper are pre-
sented in Table 1. Selected bond lengths and angles for
5 are collected in Table 2. The two triphenylphosphine
ligands are located mutually trans and the hydride li-
dride ligand trans to S. The defining feature of the 2-
iridathiophene ring is the move towards equalization
of the ring C–C bond distances. Using the numbering
system in Chart 1, C3–C4 is 1.384(4) and C4–C5 is
˚
1.403(4) A. Similar equalization of these distances is
seen in the iridathiophene structures reported by Ble-
˚
eke, 1.362(15) and 1.399(16) A in the cationic iridathi-
˚
˚
gand is trans to S. The Ir–C distance is 2.018(3) A, a
ophene [8b], 1.362(19) and 1.370(22)
A
in the
value intermediate between the values for iridium–car-
bon single and double bonds as also indicated by the
low-field 13C NMR chemical shift discussed above.
brominated iridathiophene [8b]. The combined struc-
tural and spectroscopic data for 5 suggests electron
delocalization within the five-membered metallacycle
and that it is appropriate to consider contributions to
the bonding from both valence bond structures C
and D in Chart 1.
˚
The Ir–S distance is 2.4048(7) A, only slightly longer
than the value found for the Ir–S bond in the cationic
˚
iridathiophene (2.383(3) A) [8b], which also has a hy-
Table 1
Data collection and processing parameters for 5–7
Compound
5
6
7
Empirical formula
Molecular weight
Crystal system
Space group
C53H44IIrP2S
1093.98
C50H40ClIrP2 Æ 2CH2Cl2
1100.26
C65H52ClIrP2S2
1186.78
Monoclinic
P21/n
Orthorhombic
Pbca
Monoclinic
P21/n
˚
a (A)
11.7400(2)
17.4351(3)
21.2830(3)
90.0
11.0556(2)
23.3614(3)
35.3358(3)
90.0
14.8861(4)
18.9695(5)
18.5187(5)
90.0
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
94.3560(10)
90.0
90.0
90.0
91.738(1)
90.0
3
˚
V (A)
4 343.79(12)
4
1.673
9 126.3(2)
8
1.602
5 226.9(2)
4
1.508
Z
Dcalc (g cmꢀ3
F(0 0 0)
l (mmꢀ1
Crystal size (mm)
)
2 152
3.943
4 384
3.325
2 392
2.789
)
0.36 · 0.20 · 0.12
1.92–27.23
9545, Rint 0.0299
0.331, 0.649
1.062
0.22 · 0.10 · 0.10
1.74–25.76
8735 Rint 0.0597
0.528, 0.732
1.221
0.42 · 0.32 · 0.20
1.54–27.09
10,528 Rint 0.0139
0.366, 0.572
1.077
h (Min–max) (ꢁ)
Independent reflections (I > 2r(I))
T(min,max)
Goodness-of-fit on F2
R, wR2(observed data)
R, wR2(all data)
0.0246, 0.0573
0.0308, 0.0605
0.0704, 0.1274
0.1049, 0.1389
0.0179, 0.0417
0.0212, 0.0433
P
P
P
2
2
2
1=2
aR ¼ kF oj ꢀ jF ck=RjF oj:wR2 ¼ f ½ðwðF Þo ꢀ F c2Þ ꢁ= ½wðF 2oÞ ꢁg
.

976
G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
Table 2
4) and a reasonable explanation for the presence of the
hydride ligand is that it arose from a b-hydrogen elimi-
nation reaction of the styryl ligand. Accordingly, the
reaction of IrCl(CS)(PPh3)2 with Hg(CH@CPh2)2, in
which there is no b-hydrogen in the vinyl group, was ex-
plored. An added advantage of Hg(CH@CPh2)2 is that
regardless of the orientation about the carbon–carbon
double bond in the resulting iridium-bound vinyl ligand,
there will always be a phenyl group in a position appro-
priate for ortho-metalation. There are several reports of
such ortho-metalation reactions leading to metallaind-
ene complexes, e.g., [20]. As depicted in Scheme 3, this
reaction does lead to a 1-iridaindene, the orange com-
plex, Ir[C8H5(Ph-3)]Cl(PPh3)2 (6), (in only 20% yield)
but surprisingly this compound no longer incorporates
a CS ligand. Complete loss of a CS ligand is very unu-
sual and a clue as to the fate of this ligand is provided
by a second product isolated from this reaction (in only
8% yield) which has two S atoms in a dithiocarboxylate
ligand, the dark-red complex, Ir(j2-S2CCH@CPh2)
Cl(CH@CPh2)(PPh3)2 (7). In view of the low yields of
the isolated products and their complex and unexpected
nature, we do not feel that it is useful to speculate on the
details of the reaction pathway. Nevertheless, complexes
6 and 7 have both been fully characterised including by
crystal structure determination.
˚
Selected bond lengths (A) and angles (ꢁ) for 5
Bond lengths
Ir–I
Ir–S
2.7589(2)
2.4048(7)
2.3482(7)
2.3209(7)
2.018(3)
1.687(3)
1.384(4)
1.487(4)
1.403(4)
1.459(4)
1.326(4)
1.460(4)
Ir–P1
Ir–P2
Ir–C1
S–C3
C1–C2
C1–C12
C2–C3
C3–C4
C4–C5
C5–C6
Bond angles
I–Ir–S
I–Ir–P1
99.03(2)
84.91(2)
88.46(2)
177.12(8)
169.43(3)
83.04(8)
118.0(2)
121.4(3)
118.5(2)
116.8(2)
125.2(3)
124.2(3)
I–Ir–P2
I–Ir–C1
P1–Ir–P2
S–Ir–C1
Ir–C1–C2
C1–C2–C3
S–C3–C2
S–C3–C4
C3–C4–C5
C4–C5–C6
2.3. Reaction between IrCl(CS)(PPh3)2 and
Hg(CH@CPh2)2 leading to a mixture of the
1-iridaindene, Ir[C8H5(Ph-3)]Cl(PPh3)2 (6) and
the dithiocarboxylate complex, Ir(j2-S2CCH@CPh2)
Cl(CH@CPh2)(PPh3)2 (7), and the crystal structure
determinations of these complexes
In the 1H NMR spectrum of 6, there is an unresolved
triplet at 7.42 ppm assigned to the iridium-bound CH,
and in the 13C NMR spectrum, triplet resonances at
131.6 ppm (2JCP = 8.1 Hz) and 141.8 ppm (2JCP = 6.5
Hz) are assigned to the two iridium-bound carbon
atoms, IrCH and IrC, respectively. An interesting fea-
ture of complex 6 is that it is coordinatively unsaturated.
In a future publication, we will report on the further
reactions of this compound.
The reaction between IrCl(CS)(PPh3)2 and
Hg(CH@CHPh)2, as detailed above in Section 2.2, did
not lead to an iridanaphthalene which had been our ori-
ginal aim as discussed Section 1. Instead, the reaction
pathway led to a molecule with an Ir–H bond (complex
The molecular geometry of 6 is shown in Fig. 2. Se-
lected bond lengths and angles for 6 are collected in Ta-
ble 3. The two triphenylphosphine ligands are again
PPh3
20%
Cl
Ir
Ph
PPh3
(6)
PPh3
Ir
Hg(CH=CPh2)2
Cl
CS
PPh3
PPh3
Ph
Ph
(3)
S
S
C
Ir
8%
Ph
Cl
PPh3
Ph
(7)
Scheme 3. Reaction between IrCl(CS)(PPh3)2 and Hg(CH@CPh2)2.

G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
977
ulate that the dithiocarboxylate ligand arises in some
way from intermolecular S atom abstraction from the
CS ligand by a thioacyl ligand. In the 1H NMR spectrum
of 7, a triplet signal at 8.52 ppm (3JHP = 3.2 Hz) is as-
signed to the proton of the iridium-bound vinyl group
and a singlet signal at 5.61 ppm is assigned to the proton
of the vinyl substituent on the dithiocarboxylate ligand.
In the 13C NMR spectrum, a triplet signal at 142.6
ppm (2JCP = 3.2 Hz) is assigned to the iridium-bound
carbon and another triplet at 235.3 (3JCP = 3.6 Hz) is as-
signed to the dithiocarboxylate carbon.
The molecular geometry of 7 is shown in Fig. 3. Se-
lected bond lengths and angles for 7 are collected in Ta-
ble 4. The two triphenylphosphine ligands are again
Fig. 2. The molecular geometry and atomic numbering scheme for
Ir[C8H5(Ph-3)]Cl(PPh3)2 (6) (for clarity, phenyl rings on the triphe-
nylphosphine ligands are not shown).
Table 3
˚
Selected bond lengths (A) and angles (ꢁ) for 6
Bond lengths
Ir–Cl
Ir–P1
Ir–P2
2.402(2)
2.336(2)
2.330(2)
1.982(10)
2.004(10)
1.344(13)
1.457(14)
1.475(13)
1.427(14)
Ir–C1
Ir–C4
C1–C2
C2–C3
C2–C9
C3–C4
Fig. 3. The molecular geometry and indicative atomic numbering
scheme for Ir(j2-S2CCH@CPh2)Cl(CH@CPh2)(PPh3)2 (7) (for clarity,
phenyl rings on the triphenylphosphine ligands are not shown).
Numbering of the illustrated phenyl rings is, clockwise around the
rings, C4–C9, C10–C15, C18–C23 and C24–C29.
Bond angles
Cl–Ir–P1
Cl–Ir–P2
91.19(8)
90.70(8)
136.7(3)
147.2(3)
176.61(9)
76.1(4)
Cl–Ir–C1
Cl–Ir–C4
P1–Ir–P2
C1–Ir–C4
Ir–C1–C2
C1–C2–C3
C1–C2–C9
C2–C3–C4
Ir–C4–C3
Table 4
˚
Selected bond lengths (A) and angles (ꢁ) for 7
Bond lengths
Ir–Cl
2.4392(4)
2.3350(4)
2.4604(5)
2.3745(5)
2.3566(5)
2.081(2)
1.694(2)
1.709(2)
1.4559(3)
1.355(3)
1.351(3)
122.9(8)
111.3(9)
123.3(9)
111.0(9)
118.7(7)
Ir–S1
Ir–S2
Ir–P1
Ir–P2
Ir–C16
S1–C1
S2–C1
C1–C2
C2–C3
C16–C17
located mutually trans with Ir–P distances of 2.336(2)
˚
˚
and 2.330(2) A. The Ir–Cl distance is 2.402(2) A and this
is close to the average for 65 recorded observations for
Ir–Cl bonds in five-coordinate iridium (2.3851 with a
˚
Bond angles
Cl–Ir–S1
Cl–Ir–S2
SD of 0.0382 A, Cambridge Crystallographic Data-
˚
Base). The Ir–CH distance is 1.982(10) A and the other
˚
Ir–C distance is 2.004(10) A. These values are less than
would be expected for single bonds, which is consistent
with some degree of multiple bond character, although
the five-coordinate nature of 6 will also be influencing
these distances. There is, however, little evidence for
any delocalization within the five-membered ring since
C1–C2 (see Fig. 2) is 1.344(13) A, whereas C2–C3 is
˚
1.457(14) and C3–C4 is 1.427(14) A.
The minor product of the reaction depicted in Scheme
3, is the dark-red, dithiocarboxylate complex, Ir(j2-
S2CCH@CPh2)Cl(CH@CPh2)(PPh3)2 (7). One can spec-
172.64(1)
101.33(1)
87.32(2)
89.09(2)
85.40(5)
175.08(2)
71.41(1)
101.89(5)
173.19(5)
91.13(6)
86.61(7)
110.78(11)
130.3(2)
140.16(14)
Cl–Ir–P1
Cl–Ir–P2
Cl–Ir–C16
P1–Ir–P2
S1–Ir–S2
S1–Ir–C16
S2–Ir–C16
Ir–S1–C1
Ir–S2–C1
S1–C1–S2
C1–C2–C3
Ir–C16–C17
˚

978
G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
located mutually trans with Ir–P distances of 2.3566(5)
tained operating at 300.13 (1H), 75.48 (13C) MHz, and
121.50 (31P) MHz, respectively. Resonances are quoted
˚
˚
and 2.3745(5) A. The Ir–Cl distance is 2.4392(4) A,
slightly longer than the average for 496 recorded obser-
vations for Ir–Cl bonds in six-coordinate iridium
1
in ppm and H NMR spectra referenced to either tetra-
methylsilane (0.00 ppm) or the proteo-impurity in the
solvent (7.25 ppm for CHCl3). 13C NMR spectra were
referenced to CDCl3 (77.00 ppm), and 31P NMR spectra
to 85% orthophosphoric acid (0.00 ppm) as an external
standard. Elemental analyses were obtained from the
Microanalytical Laboratory, University of Otago.
˚
(2.4087 with a SD of 0.0669 A, Cambridge Crystallo-
˚
graphic DataBase). The Ir–C distance is 2.081(2) A. This
and all other features of the iridium-bound diphenylvi-
nyl group are unremarkable. The attachment of the
dithiocarboxylate is unsymmetrical with the longer
˚
Ir–S distance (2.4604(5) A) trans to the diphenylvinyl
˚
ligand and the shorter Ir–S distance (2.3350(4) A) trans
to chloride. Presumably, this is a reflection of the rela-
tive trans influences of the carbon donor and the chlo-
ride. Similar observations have frequently been made
for related dithiocarbamate complexes [21].
4.2. Preparation of [Ir(j2-
C[S]SMe)Cl(CO)(PPh3)2]CF3SO3 (1)
IrCl(CO)(PPh3)2 (2.00 g, 2.56 mmol) was stirred in
CS2 (50 mL) until fully dissolved. Methyl triflate (1.25
mL, 11.0 mmol) was added and the resulting solution
stirred for 4 h to afford a pale yellow suspension. Ben-
zene (50 mL) was added to complete precipitation and
the pale yellow solid collected by filtration (CAUTION:
filtrate will contain unreacted methyl triflate). The solid
was recrystallised from dichloromethane/benzene to give
pure 1 as an off-white microcrystalline solid (2.58 g, 94
3. Conclusions
It has been demonstrated that the introduction of 2-
phenylvinyl ligands to IrCl(CS)(PPh3)2, through reac-
tion with Hg(CH@CHPh)2, leads to the assembly of a
2-iridathiophene through ligand combination of CS
and two 2-phenylvinyl fragments. The initial hydride-
1
%). The H NMR spectrum shows the presence of ben-
zene of solvation (2/3 of a molecule of benzene per mol-
ecule of complex), consistent with the elemental
analysis. Anal. Calc. for C40H33ClF3IrO4P2S3 Æ 2/
3C6H6: C, 49.21; H, 3.60. Found: C, 49.22; H, 3.60%.
IR (cmꢀ1): 2038s m(CO); 1272s, 1261s, 1153s, 1030s.
1H NMR (CDCl3, d): 2.19 (s, 3H, CS2Me), 7.47–7.70
containing
2-iridathiophene,
Ir[SC3H(Ph-3)(CH@
CHPh-5)]HCl(PPh3)2 (4) is readily converted to
Ir[SC3H(Ph-3)(CH@CHPh-5)]HI(PPh3)2 (5) and spec-
troscopic data for both and the crystal structure of 5
confirm the 2-iridathiophene formulation. By using
Hg(CH@CPh2)2 instead of Hg(CH@CHPh)2 in the reac-
tion with IrCl(CS)(PPh3)2, the absence of a b-hydrogen
diverts the reaction away from 2-iridathiophene forma-
tion and produces, in low yield, the coordinatively
unsaturated 1-iridaindene, Ir[C8H5(Ph-3)]Cl(PPh3)2 (6),
which no longer retains a CS ligand, and the chelated
dithiocarboxylate complex, Ir(j2-S2CCH@CPh2)Cl-
(CH@CPh2)(PPh3)2 (7).
(m, 30H, PPh3). 13C NMR (CDCl3, d): 30.7 (s, CS2Me),
1,3
125.9 (t0 [22],
J
= 59.8 Hz, i-C6H5), 129.3 (t0,
CP
2,4
J
J
= 11.0 Hz, o-C6H5), 132.6 (s, p-C6H5), 134.3 (t0,
CP
3,5
2
= 10.8 Hz, m-C6H5), 168.8 (t, JCP = 8.3 Hz,
CP
2
CO), 239.7 (t, JCP = 3.9 Hz, CS2Me). 31P NMR
(CDCl3, d): ꢀ2.50 (s, PPh3).
4.3. Preparation of IrHCl(C[S]SMe)(CO)(PPh3)2 (2)
In
a
Schlenk tube, [Ir(j2-C[S]SMe)Cl(CO)-
4. Experimental
(PPh3)2]CF3SO3 (1) (2.50 g, 2.45 mmol) was suspended
in ethanol (20 mL) and treated with a solution of so-
dium borohydride (0.50 g, 13.2 mmol) in ethanol (10
mL). The solution was stirred for 15 min to produce
an orange-pink solid which was collected by filtration.
This was recrystallised from dichloromethane/ethanol
to afford pure 2 as pink crystals (1.62 g, 76%). Anal.
Calc. for C39H34ClIrOP2S2: C, 53.69; H, 3.93. Found:
C, 53.69, H, 4.01%. IR (cmꢀ1): 2036s m(CO), 985m
(CS2Me). 1H NMR (CDCl3, d): ꢀ11.91 (t, 1H,
2JHP = 14.0 Hz, IrH) 1.94 (s, 3H, CS2Me), 7.32–7.75
4.1. General procedures and instruments
Standard laboratory procedures were followed as
have been described previously [22]. The compounds
IrCl(CO)(PPh3)2 [23], Hg(CH@CHPh)2 [24,25], and
Hg(CH@CPh2)2 [25,26], were prepared by the literature
methods.
Infrared spectra (4000-400 cmꢀ1) were recorded as
Nujol mulls between KBr plates on a Perkin Elmer Par-
agon 1000 spectrometer. NMR spectra were obtained on
either a Bruker DRX 400 or a Bruker Avance 300 at 25
(m, 30H, PPh3). 13C NMR (CDCl3, d): 20.8 (s, Me),
2,4
127.8 (t0,
J
= 10.0 Hz, o-C6H5) 129.7 (t0,
CP
ꢁC. For the Bruker DRX 400, H, 13C and 31P NMR
J
J
= 58.4 Hz, i-C6H5), 130.7 (s, p-C6H5), 134.7 (t0,
1
1,3
CP
spectra were obtained operating at 400.1 (1H), 100.6
(13C) and 162.0 (31P) MHz, respectively. For the Bruker
3,5
2
= 10.0 Hz, m-C6H5), 161.4 (t, JCP = 8.0 Hz,
CP
CO), 288.7 (m, CS2Me). 31P NMR (CDCl3, d): ꢀ1.46
1
Avance 300, H, 13C, and 31P NMR spectra were ob-
(s, PPh3).

G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
979
4.4. Preparation of IrCl(CS)(PPh3)2 (3)
CH2Cl2 and the extract concentrated and purified by
chromatography using a silica gel column and eluting
with a mixture of CH2Cl2/hexane (3:2). The dark brown
band was collected and from this was obtained pure 5
(0.098 g, 90%). Anal. Calc. for C53H44IIrP2S: C, 58.19;
H, 4.05. Found: C, 58.24; H, 4.14%. IR (cmꢀ1):
2221w, m(IrH). 1H NMR (CDCl3, d): ꢀ11.95 (t, 1H,
2JPH = 16.0 Hz, IrH), 6.79–7.54, (m, 43H, multiplet sig-
nals not individually assigned from PPh3, H, Ph, and
IrHCl(C[S]SMe)(CO)(PPh3)2 (2) (1.60 g, 1.83 mmol)
was suspended in t-butanol (40 mL) and heated under
reflux for 11 h with a slow stream of nitrogen passing
through the suspension. The resulting yellow-orange
suspension was filtered to give an orange solid which
was recrystallised from dichloromethane/ethanol to give
pure 3 as orange crystals (1.40 g, 95.8%). Characteriza-
tion was by comparison with literature spectroscopic
data [17].
styryl substituents on iridathiophene). 13C NMR
2,4
(CDCl3, d): 127.1 (t0,
J
= 10.0 Hz, o-C6H5P), 129.6
J
CP
1,3
(s, p-C6H5P), 133.0 (t0,
= 55.4 Hz, i-C6H5P),
CP
3,5
4.5. Preparation of Ir[SC3H(Ph-3)(CH@CHPh-
5)]HCl(PPh3)2 (4)
134.9 (t0,
J
= 10.0 Hz, m-C6H5P); singlet signals
CP
all CH, not individually assigned, at 126.6, 127.9,
128.8, 129.0, 130.3, 135.8 from Ph, and styryl substitu-
ents on iridathiophene; 137.4 (s, quat., tentatively as-
signed as quaternary carbon from bound styryl
phenyl), 144.6 (s, tert., C4), 150.0 (s, quat., tentatively
assigned as quaternary carbon from phenyl substituent
on ring C3), 211.7 (t, coupling unresolved, quat., ring
C5), 225.0 (t, coupling unresolved, quat., ring C3). 31P
NMR (CDCl3, d): ꢀ1.22 (s).
A suspension of IrCl(CS)(PPh3)2 (0.127 g, 0.16 mmol)
and Hg(CH@CHPh)2 (0.072 g, 0.18 mmol) in benzene
(20 mL) was heated under reflux for 5 min to give a dark
red solution with a precipitate of elemental mercury.
The mercury was removed by filtration through Celite
and all volatiles then removed from the filtrate under re-
duced pressure. The residue was taken up in CH2Cl2 and
purified by column chromatography on silica gel using
first a mixture of CH2Cl2 and hexane (v/v = 1:1), and
then pure CH2Cl2 as eluents. The major brown band
from the CH2Cl2 eluent was collected, and the isolated
solid recrystallised from CH2Cl2/EtOH/heptane to give
pure 4 as greenish black crystals (0.120 g, 75%). Anal.
Calc. for C53H44ClIrP2S0. 5CH2Cl2: C, 61.49; H, 4.34.
Found: C, 61.61; H, 4.46%. IR (cmꢀ1): 2195, m(IrH).
4.7. Preparation of Ir[C8H5(Ph-3)]Cl(PPh3)2 (6)
A mixture of IrCl(CS)(PPh3)2 (0.240 g, 0.30 mmol)
and Hg(CH@CPh2)2 (0.198 g, 0.33 mmol) in benzene
(30 mL) was heated under reflux for 2 h to give a dark
reddish brown solution with a precipitate of elemental
mercury. After filtering through Celite to remove the
mercury, the solvent was removed under reduced pres-
sure. The crude product was dissolved in CH2Cl2 and
subjected to column chromatography on silica gel elut-
ing with CH2Cl2 and hexane (v/v = 1:1). The dark
brown band was collected and the isolated solid recrys-
tallised from CH2Cl2 and EtOH to give pure 6 as an or-
ange solid (0.056 g, 20%) and the filtrate from the
recrystallization was reserved for treatment as described
in Section 4.8 below. The bulk sample of 6, when recrys-
tallised as above and dried over P2O5 under vacuum, re-
turned elemental analysis figures consistent with the
sample being unsolvated. However, the single crystal
chosen for X-ray analysis was grown at room tempera-
ture over several days from CH2Cl2/EtOH and proved
to be a 1:1 CH2Cl2 solvate (see Table 1). Anal. Calc.
for C50H40ClIrP2: C, 64.54; H, 4.33. Found: C, 64.54;
2
1H NMR (CDCl3, d): ꢀ11.11 (t, 1H, JPH = 14.0 Hz,
IrH), 6.76–7.54, (m, 43H, multiplet signals not individu-
ally assigned from PPh3, H, Ph, and styryl substituents
13
on iridathiophene). C NMR (CDCl3, d): 127.3 (t0,
2,4
J
= 10.0 Hz, o-C6H5P), 129.6 (s, p-C6H5P), 132.4
3,5
CP
CP
1,3
(t0,
J
= 55.4 Hz, i-C6H5P), 134.6 (t0,
J
= 10.0
CP
Hz, m-C6H5P); singlet signals all CH, not individually
assigned, at 126.5, 127.8, 128.8, 129.4, 129.7, 130.1,
136.8, from Ph, and styryl substituents on iridathioph-
ene; 135.9 (s, quat., tentatively assigned as quaternary
carbon from bound styryl phenyl), 144.9 (s, tert., C4),
150.4 (s, quat., tentatively assigned as quaternary car-
bon from phenyl substituent on ring C3), 209.8 (t, cou-
pling unresolved, quat., ring C5), 222.9 (t, coupling
unresolved, quat., ring C3). 31P NMR (CDCl3, d): 6.27
(s).
1
H, 4.39%. H NMR (CDCl3, d): 6.10–7.36, (m, 39H,
multiplet signals not individually assigned from PPh3,
4.6. Preparation of Ir[SC3H(Ph-3)(CH@CHPh-
5)]HI(PPh3)2 (5)
iridaindeneH, and Ph substituent on iridaindene); 7.42
(unresolved triplet, 1H, iridaindene C2H). 13C NMR
2,4
Ir[SC3H(Ph-3)(CH@CHPh-5)]HCl(PPh3)2 (0.100 g,
0.10 mmol) dissolved in CH2Cl2 (10 mL) and NaI
(0.075 g, 0.5 mmol) dissolved in a mixture of EtOH
(10 mL) and water (0.5 mL) were combined. After stir-
ring for 16 h all the volatiles were removed under re-
duced pressure. The residue was extracted with
(CDCl3, d): 127.8 (t0,
J
= 10.0 Hz, o-C6H5P), 129.7
CP
1,3
(t0,
J
= 54.4 Hz, i-C6H5P), 129.9 (s, p-C6H5P),
CP
3,5
134.7 (t0,
J
= 10.0 Hz, m-C6H5P); singlet signals
CP
all CH, not individually assigned, at 121.5, 122.2,
123.1, 125.3, 127.1, 127.2, 132.1, from Cꢀs of iridaindene
six-membered ring and Ph substituent on iridaindene;

980
G.-L. Lu et al. / Journal of Organometallic Chemistry 690 (2005) 972–981
131.6 (t, 2JCP = 8.1 Hz, iridaindene C2H), 139.7 (s, quat.
C, unassigned), 141.8 (t, 2JCP = 6.5 Hz, iridaindene CIr),
154.6 (unresolved triplet, quat. C, unassigned), 156.4 (s,
quat. C, unassigned). 31P NMR (CDCl3, d): 24.33 (s).
data and refinement details for all three structures are gi-
ven in Table 1.
5. Supplementary material
4.8. Preparation of Ir(j2-S2CCHCPh2)Cl(CH@CPh2)
(PPh3)2 (7)
Crystallographic data (excluding structure factors)
for 5, 6, and 7 have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publica-
tion nos. CCDC 245794, 245795 and 245796 respec-
tively. Copies of this information can be obtained free
of charge from the Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (Fax: +44-1223-336-033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://www.
ccdc.cam.ac.uk).
The solvent was removed from the filtrate left in the
recrystallization step described in Section 4.7. The
resulting residue was recrystallised from CH2Cl2 and
heptane to give pure 7 as a dark red solid (0.028 g,
8%). The bulk sample of 7, when recrystallised as above
and dried over P2O5 under vacuum, returned elemental
analysis figures consistent with the sample retaining
1
0.25 molecules of CH2Cl2 of solvation. The H NMR
of this analytical sample confirmed the presence of
CH2Cl2 in an approximately 0.25:1 ratio with the com-
plex. However, the single crystal of 7 chosen for X-ray
analysis was grown at room temperature over several
days from CH2Cl2/heptane and proved to be unsolvated
(see Table 1). Anal. Calc. for C65H52ClIrP2-
S2 Æ 0.25CH2Cl2: C, 64.87; H, 4.38; S, 5.31. Found: C,
Acknowledgements
We thank the Marsden Fund administered by the
Royal Society of NZ for supporting this work. We also
thank Dr. K.G. Town for performing some of the origi-
nal work on the preparation of IrCl(CS)(PPh3)2.
1
64.79; H, 4.32; S, 5.20%. H NMR (CDCl3, d): 5.61 (s,
1H, S2CCH@), 6.24–7.49 (m, 50H, multiplet signals
not individually assigned from PPh3, and the four Ph
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