A 2-iridafuran from reaction between a 1-iridaindene and methyl propiolate

Article abstract of DOI:10.1016/j.jorganchem.2006.05.035

The coordinatively unsaturated 1-iridaindene, Ir[C₈H₅(Ph-3)]Cl(PPh₃)₂ has a labile chloride ligand and is easily converted to the corresponding iodide, Ir[C₈H₅(Ph-3)]I(PPh₃)₂ (1) by reaction with NaI. When Ir[C₈H₅(Ph-3)]I(PPh₃)₂ (1) is treated with methyl propiolate a reactive five-coordinate complex with both a diphenylvinyl ligand from ring-opening of the 1-iridaindene, and a 3-methoxy-3-oxoprop-1-ynyl ligand from deprotonation of methyl propiolate, is first produced. Reaction of this complex with aqueous HCl generates the 2-iridafuran, Ir[OC₃H(CH{double bond, long}CPh₂-3)(OMe-5)]ClI(PPh₃)₂ (2) probably from initial protonation at the β-carbon of the 3-methoxy-3-oxoprop-1-ynyl ligand to form a vinylidene ligand and subsequent migration of the diphenylvinyl ligand to the α-carbon of this ligand accompanied by oxygen coordination to iridium. Similar treatment of 1 with methyl propiolate followed by aqueous HI gives the corresponding complex, Ir[OC₃H(CH{double bond, long}CPh₂-3)(OMe-5)]I₂(PPh₃)₂ (3). The X-ray crystal structures of 2 and 3 together with NMR spectroscopic data confirm the 2-metallafuran structures of these complexes.

Full text of DOI:10.1016/j.jorganchem.2006.05.035

Journal of Organometallic Chemistry 691 (2006) 3846–3852
www.elsevier.com/locate/jorganchem
A 2-iridafuran from reaction between a 1-iridaindene
and methyl propiolate
*
*
Anja Bierstedt, George R. Clark, Warren R. Roper , L. James Wright
Department of Chemistry, The University of Auckland, Private Bag 92019, 23 Symonds Street, Auckland 1020, New Zealand
Received 12 April 2006; received in revised form 10 May 2006; accepted 16 May 2006
Available online 3 June 2006
Abstract
The coordinatively unsaturated 1-iridaindene, Ir[C8H5(Ph-3)]Cl(PPh3)2 has a labile chloride ligand and is easily converted to the cor-
responding iodide, Ir[C8H5(Ph-3)]I(PPh3)2 (1) by reaction with NaI. When Ir[C8H5(Ph-3)]I(PPh3)2 (1) is treated with methyl propiolate
a reactive five-coordinate complex with both a diphenylvinyl ligand from ring-opening of the 1-iridaindene, and a 3-methoxy-3-oxoprop-
1-ynyl ligand from deprotonation of methyl propiolate, is first produced. Reaction of this complex with aqueous HCl generates the
2-iridafuran, Ir[OC3H(CH@CPh2-3)(OMe-5)]ClI(PPh3)2 (2) probably from initial protonation at the b-carbon of the 3-methoxy-3-oxo-
prop-1-ynyl ligand to form a vinylidene ligand and subsequent migration of the diphenylvinyl ligand to the a-carbon of this ligand
accompanied by oxygen coordination to iridium. Similar treatment of 1 with methyl propiolate followed by aqueous HI gives the cor-
responding complex, Ir[OC3H(CH@CPh2-3)(OMe-5)]I2(PPh3)2 (3). The X-ray crystal structures of 2 and 3 together with NMR spectro-
scopic data confirm the 2-metallafuran structures of these complexes.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Iridafuran; Iridaindene; Iridium; X-ray crystal structure
1. Introduction
complexes as well as metallafurans. The extent to which
these compounds exhibit aromatic character varies, but
aromaticity is well established for some [5] using the criteria
of ring planarity, bond delocalization from structural data,
NMR chemical shifts, and the observation of electrophilic
substitution reactions. There is a very extensive literature
relating to these compounds and they have been prepared
in a great variety of ways. The principal routes are depicted
in Chart 1 and we discuss these methods with representa-
tive but necessarily selective references. The most common
synthesis is from insertion of an alkyne into the MAC bond
of a metal-acyl complex (Method 1, Chart 1) [6]. Insertion
of an alkyne bearing an ester function into a metalAX
bond offers another well-documented route (Method 2,
Chart 1) [7]. An early and very direct approach involves
CAH oxidative addition of an alkene bearing an ester or
related function to a low oxidation state metal center
(Method 3, Chart 1) [8]. Oxidation of a metallacyclobutadi-
ene is a further route to metallafurans (Method 4, Chart 1)
[9]. Closely related to this is the oxidation of a cationic
Aromatic metallacycles continue to be the subject of
extensive investigation. While metallabenzenes are an obvi-
ous focus of attention there is also interest in metalla-
heteroaromatic molecules [1]. This group includes the
five-membered ring compounds, the metallafurans, metal-
lathiophenes and metallapyrroles. While examples of
metallathiophenes [2,3] and metallapyrroles [4] are quite
scarce, there are numerous examples of metallafurans [5]
involving metals across the transition series. By metallafu-
rans we understand molecules with the five-membered ring
connectivity shown in Chart 1, although in the literature
such compounds have been variously referred to as che-
lated vinyl ketone complexes or oxametallacyclopentadiene
*
Corresponding authors. Tel.: +64 9 373 7999x88320; fax: +64 9 373
7422.
E-mail addresses: w.roper@auckland.ac.nz (W.R. Roper), lj.wright@
auckland.ac.nz (L.J. Wright).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.05.035

A. Bierstedt et al. / Journal of Organometallic Chemistry 691 (2006) 3846–3852
3847
2. Results and discussion
R'
R''
O
C
R'C CR''
M
M
(1)
(2)
M
2.1. The reaction between the iridaindene,
Ir[C8H5(Ph-3)]I(PPh3)2 (1), and methyl propiolate
R
R
O
O
R
X
H
R
RC CO2Me
The chloride derivative of the iridaindene, Ir[C8H5(Ph-
3)]Cl(PPh3)2, was originally prepared from the reaction
between IrCl(CS)(PPh3)2 and Hg(CH@CPh2)2, in 20%
yield [3]. A superior method of preparation is the reaction
between IrHCl2(PPh3)3 and Hg(CH@CPh2)2 which pro-
ceeds in 66% yield. This procedure is described in Section
4.2 of this paper. Because of the convenience of increased
solubility, we have preferred to work with the iodide deriv-
ative of the iridaindene, Ir[C8H5(Ph-3)]I(PPh3)2 (1), and
this is easily prepared from the chloride by treatment with
NaI as shown in Scheme 1. Spectroscopic data for com-
plexes 1, 2, and 3 are collected in Section 4. The 13C and
31P NMR chemical shifts for 1 are very close to those
observed for Ir[C8H5(Ph-3)]Cl(PPh3)2 [3].
When a solution of 1 in dichloromethane with a large
excess of methyl propiolate is heated under reflux the color
of the solution changes from red to orange-yellow.
Removal of all volatiles gives a yellow-brown product
which could not be fully purified but which we formulate
as the five coordinate acetylide, vinyl complex of irid-
ium(III), Ir(C„CCO2Me)(CH@CPh2)I(PPh3)2 (A) (see
Scheme 1). This formulation is based on the following spec-
troscopic data and upon the product formed on reaction
with CO. In the IR spectrum of A there is a strong band
at 2112 cmꢀ1 which is assigned to the terminal acetylide
ligand (mC„C), and another at 1681 cmꢀ1 assigned to the
X
M
(X = H, I, Hg)
OMe
OMe
R
H
H
H
C
C
H
CO2Me
(3)
(4)
M
M
M
H
O
O
R
C
R
[O]
C
R
M
C
R
+
R
R
H
H
H
R
C
[O]
(5)
(6)
(7)
M
M
C
M
(-H+)
R
C
R
R
O
H
R
H2
C
C
C
M
R
O
O
O
R
R
H
M
C
C
M
OMe
C
OMe
O
Chart 1. Major synthetic routes to metallafurans.
1
methyl ester function of this acetylide ligand. In the H
NMR spectrum of A a singlet at 3.49 ppm is assigned to
the methyl group of the ester and aromatic protons
are seen in an envelope at 6.61–7.68 ppm. The unique
vinylcarbene complex (Method 5, Chart 1) [10]. In one
instance a carbyne complex bearing a keto-function rear-
ranges to a metallafuran (Method 6, Chart 1) [11]. Further
rather special approaches include the reaction between an
iridium ketene complex and an alkyne [12], and the reac-
tion of a ruthenium vinylidene complex with silver acety-
lide where the acetylide bears a methyl ester function [13].
While exploring the attempted insertion of a vinylidene
ligand into the five-membered ring of an iridaindene we
discovered that methyl propiolate opened the iridaindene
ring and upon the addition of acid a migratory insertion
reaction ensued, generating an iridafuran (Method 7,
Chart 1).
Herein, we report (i) the reaction between Ir[C8H5-
(Ph-3)]I(PPh3)2 (1) and methyl propiolate to form a
reactive five-coordinate complex containing both a diphe-
nylvinyl ligand from ring-opening of the 1-iridaindene,
and a 3-methoxy-3-oxoprop-1-ynyl ligand from deprotona-
tion of methyl propiolate, (ii) the reaction of this complex
with either HCl or HI to give either the 2-iridafuran,
Ir[OC3H(CH@CPh2-3)(OMe-5)]ClI(PPh3)2 (2) or the cor-
responding di-iodide, Ir[OC3H(CH@CPh2-3)(OMe-5)]I2-
(PPh3)2 (3), and (iii) the crystal structure determinations
of complexes 2 and 3.
PPh3
PPh3
Ir
Ph
Ph
NaI
Cl Ir
Ph3P
I
Ph3P
(1)
HC CCO2Me
*
PPh
+ X-
HX
3 H
C
PPh
3 H
C
I
I
Ir
Ph
Ir
C
C
Ph
H
C
C
C
PPh3
Ph
C
PPh3
Ph
MeO2C
CO2Me
(B)
(A)
X- (X=Cl)
H
X-
(X=I)
Ph
Ph
H
PPh3
C
C
Ph
Ph
C
C
PPh3
Ir
PPh3
I
I
I
Ir
Cl
O
OMe
O
OMe
PPh3
(2)
(3)
Scheme 1. Synthesis of iridafurans 2 and 3.

3848
A. Bierstedt et al. / Journal of Organometallic Chemistry 691 (2006) 3846–3852
diphenylvinyl proton is seen as an unresolved multiplet at
7.88 ppm and integral ratios for all these signals are appro-
priate. The 13C NMR spectrum of A is particularly diag-
nostic of the presence of both the acetylide ligand and
the diphenylvinyl ligand. In addition to the methyl carbon
resonance at 51.5 ppm the iridium-bound carbon of the
summarized in Method 7, Chart 1. Closely related to this
preparative method is the result described by Bruce et al.
[13] where the ester function resides on the migrating group
rather than being a substituent on the vinylidene ligand.
The 1H NMR spectra of 2 and 3 show the proton of the
diphenylvinyl group on ring position 3 (see Chart 2 for ring
numbering scheme of the 2-iridafurans) at 7.55 and
7.63 ppm, respectively; the proton on ring position 4 at
5.04 and 4.94 ppm, respectively; and the protons of the
methoxy substituent on ring position 5 at 2.66 and
2.55 ppm, respectively. The 13C NMR spectrum of 2 shows
the carbons of the diphenylvinyl group on ring position 3 at
137.1 (CH) and 143.5 (CPh2) ppm and the corresponding
resonances for 3 appear at 135.9 (CH) and 143.4 (CPh2)
ppm. The signal for the carbon at ring position 3 is a triplet
at 180.3 ppm (2JPC = 6.7 Hz), in compound 2 and the corre-
sponding triplet signal for 3 is at 179.9 ppm (2JPC = 6.7 Hz).
These low-field chemical shifts together with the significant
coupling to phosphorus suggest a degree of multiple bond-
ing between iridium and the carbon at position 3 (see
valence bond structures C and D in Chart 2), consistent with
the description of these compounds as 2-iridafurans. The
signals for the carbons at ring positions 4 and 5 are singlets
at 119.6 and 188.5 ppm, respectively, in compound 2 and the
corresponding signals for 3 are at 119.1 and 190.3 ppm. The
31P NMR spectra of 2 and 3 show the phosphorus reso-
nances as singlets at ꢀ18.44 and ꢀ25.10 ppm, respectively.
The molecular geometries of 2 and 3 are shown in Figs.
1 and 2, respectively. Crystal data pertaining to these struc-
tures are presented in Table 1. Selected bond lengths and
angles for 2 and 3 are collected in Table 2. There are two
independent molecules in each of the structures. The mole-
cules differ mostly in the orientations of the phenyl rings of
the diphenylvinyl substituents, and only one arrangement
is shown in each of the figures. In each structure the two
triphenylphosphine ligands are located mutually trans
and the two halide ligands are located mutually cis. The
structure confirms the presence of a planar five-membered
ring incorporating iridium, oxygen, and three carbon
atoms, i.e., a 2-iridafuran. The structure of 2 reveals that
the introduced chloride ligand (from HCl), takes the posi-
tion trans to carbon. There is a significant difference in the
IrAhalogen distances depending upon whether the halogen
is located trans to oxygen or carbon. For 2, where chloride
is located trans to carbon, IrAClA is 2.4602(16) and
acetylide ligand is seen as
a triplet at 72.1 ppm
(JPC = 14.64 Hz), and the other acetylide carbon is also
seen as a triplet at 97.8 ppm (JPC = 3.39 Hz). The 31P
NMR spectrum of A shows a singlet at ꢀ7.69 ppm.
Finally, very convincing evidence for the formulation of
A is that reaction with CO instantly forms the coordin-
atively saturated yellow complex, Ir(C„CCO2Me)(CH@
CPh2)I(CO)(PPh3)2 in good yield. This complex has been
fully characterized including by X-ray crystal structure
determination. The full experimental details for Ir(C„
CCO2Me)(CH@CPh2)I(CO)(PPh3)2, and its further reac-
tions, will be described in a separate paper.
There is precedent for the ring-opening of a metallacy-
clopentadiene through reaction with an acetylene. An (g2-
acetato)bis(triphenylphosphine)iridacyclopentadiene reacts
with alkynes with ring-opening of the five-membered metal-
lacycle to give (alkynyl)(but-1,3-dien-1-yl)(g2-acetato)bis-
(triphenylphosphine)iridium(III) complexes [14]. This is
closely related to the ring-opening reaction which we
observe in Scheme 1 and it may be significant that our irida-
indene, 1, is coordinatively unsaturated and that the (g2-
acetato)bis(triphenylphosphine)iridacyclopentadiene is also
potentially coordinatively unsaturated through opening of
the chelated acetate ligand. We have not observed any sim-
ilar reactions with coordinatively saturated iridaindenes
derived from complex 1, e.g., the carbonyl adduct,
Ir[C8H5(Ph-3)]I(CO)(PPh3)2.
2.2. The reactions of Ir(CBCCO2Me)(CH@CPh2)I-
(PPh3)2 (A) with either HCl or HI to form either
Ir[OC3H(CH@CPh2-3)(OMe-5)]ClI(PPh3)2 (2)
or Ir[OC3H(CH@CPh2-3)(OMe-5)]I2(PPh3)2 (3),
and the crystal structures of 2 and 3
When concentrated aqueous HCl or HI is added to a
dichloromethane solution of A prepared as described above
and the reaction mixture heated under reflux, the iridafuran
complexes, either Ir[OC3H(CH@CPh2-3)(OMe-5)]ClI-
(PPh3)2 (2) or Ir[OC3H(CH@CPh2-3)(OMe-5)]I2(PPh3)2 (3),
are formed in good yield (see Scheme 1). A reasonable ratio-
nalization of these transformations is that complex A is ini-
tially protonated at the b-carbon atom of the acetylide
ligand so forming the cationic vinylidene complex B. This
is a well-established route to vinylidene complexes [15]. A
subsequent migratory insertion reaction, involving move-
ment of the diphenylvinyl ligand to the a-carbon atom of
the vinylidene ligand, will be favored for B because of its cat-
ionic nature. Finally, ring closure by bond formation
between iridium and the carbonyl oxygen of the methyl ester
substituent, together with coordination of a halide produces
the observed red-orange iridafurans, 2 and 3. This process is
Ph
Ph
H
Ph
Ph
H
PPh3
2
PPh3
2
3
3
I
I
4
4
Ir
Ir
5
5
X
O
X
O
1
OMe
OMe
1
PPh3
PPh3
(C)
(D)
Chart 2. Valence bond structures, C and D, for the new 2-iridafurans,
Ir[OC3H(CH@CPh2-3)(OMe-5)]ClI(PPh3)2 (2) and Ir[OC3H(CH@CPh2-
3)(OMe-5)]I2(PPh3)2 (3) and the ring numbering scheme for naming of the
compounds and the NMR discussion.

A. Bierstedt et al. / Journal of Organometallic Chemistry 691 (2006) 3846–3852
3849
Table 1
Data collection and processing parameters for 2 and 3
2
3
Formula
C54H45ClIIrO2P2
1142.39
Monoclinic
Pc
C54H45I2IrO2P2
1233.84
Monoclinic
C2/c
Molecular weight
Crystal system
Space group
˚
a (A)
18.6340(2)
12.3538(2)
20.1672(2)
102.322(1)
4535.56(10)
86(2)
74.7537(1)
12.4000(1)
20.0369(1)
93.882(2)
18,530.51(15)
83(2)
˚
b (A)
˚
c (A)
b (ꢁ)
3
˚
V (A )
T (K)
Z
4
16
1.769
9568
4.325
Dcalc (g cmꢀ3
F(000)
)
1.673
2248
3.796
l (mmꢀ1
)
Crystal size (mm)
2hmin,max (ꢁ)
0.24 · 0.24 · 0.20
1.65, 26.42
26,693
14,619 (0.0265)
0.4627, 0.5173
1.097
0.20 · 0.20 · 0.20
1.64, 26.49
109,225
19,050 (0.0519)
0.3624, 0.5847
1.031
Reflections collected
Independent reflections (Rint
Tmin,max
Goodness-of-fit on F2
R, wR2 (observed data)
R, wR2 (all data)
)
Fig. 1. The molecular geometry of molecule A of Ir[OC3H(CH@CPh2-
3)(OMe-5)]ClI(PPh3)2 (2) showing the atom labeling and atoms as 50%
probability displacement ellipsoids [23]. N.B. the crystallographic atom
numbering scheme differs from that given in Chart 1.
0.0244, 0.0540
0.0261, 0.0550
0.0464, 0.0991
0.0677, 0.1071
P
P
P
P
2
2
1=2
R = iFo| ꢀ |Fci/ |Fo|, wR2 ¼ f ½wðF 2o ꢀ F c2Þ ꢁ= ½wðF o2Þ ꢁg
.
bridge Crystallographic Data Base). It is interesting that
IrAI distance trans to oxygen is at the short end of the
observed range. The observed IrAC distances are:
IrAC(1A), 2.040(6); IrAC(1B), 2.035(6) in 2 and IrAC(1A),
2.057(7); IrAC(1B), 2.051(6) in 3. All of these distances are
considerably shorter than expected for an IrAC single
bond which has an average of 2.1255 with a SD of
˚
0.0560 A (247 observations, Cambridge Crystallographic
Data Base). They are also closely comparable to those val-
ues reported for other iridafurans [5,12]. There is also evi-
dence for bond equalization in the observed iridafuran ring
CAC distances (see Table 2). Thus the structural data and
the NMR spectroscopic data discussed above are all con-
sistent with contributions to the bonding from the two
valence bond structures C and D in Chart 2.
3. Conclusions
It has been demonstrated that the coordinatively unsat-
urated iridaindene, 1, undergoes a reaction with methyl
propiolate in which the five-membered metallacyclic ring
is opened to a diphenylvinyl ligand (through protonation)
accompanied by coordination of a 3-methoxy-3-oxoprop-
1-ynyl ligand (from deprotonation of methyl propiolate).
This unexpected product reacts further with acids by initial
protonation of the b-carbon of the alkynyl ligand to give a
coordinated vinylidene ligand, followed by migration of the
diphenylvinyl ligand to the a-carbon of the vinylidene
ligand together with coordination of the ester carbonyl
oxygen to give the 2-iridafurans, Ir[OC3H(CH@CPh2-3)-
(OMe-5)]ClI(PPh3)2 (2) and Ir[OC3H(CH@CPh2-3)(OMe-
5)]I2(PPh3)2 (3). Spectroscopic and structural data for 2
and 3 support the 2-iridafuran formulations.
Fig. 2. The molecular geometry of molecule A of Ir[OC3H(CH@CPh2-
3)(OMe-5)]I2(PPh3)2 (3) showing the atom labeling and atoms as 50%
probability displacement ellipsoids [23]. N.B. the crystallographic atom
numbering scheme differs from that given in Chart 1.
˚
IrAClB is 2.4755(15) A. These values are longer than the
average for 572 recorded observations for IrACl bonds in
˚
6-coordinate iridium (2.4046 with a SD of 0.066 A, Cam-
bridge Crystallographic Data Base). For 3, the iodide
located trans to carbon has the longer IrAI bond at
˚
IrAI(2A), 2.7563(5), IrAI(2B), 2.7764(5) A compared to
the iodide trans to oxygen at IrAI(1A), 2.6639(5), IrAI(1B),
˚
2.6668(5) A. These values can be compared with the aver-
age for 123 recorded observations for IrAI bonds in
˚
6-coordinate iridium (2.7564 with a SD of 0.060 A, Cam-

3850
A. Bierstedt et al. / Journal of Organometallic Chemistry 691 (2006) 3846–3852
Table 2
˚
Selected bond lengths (A) and angles (ꢁ) for 2 and 3
2
3
Bond lengths
IrAAC(1A)
IrAAO(1A)
IrAAP(2A)
IrAAP(1A)
IrAAClA
2.040(6)
2.086(4)
2.3606(13)
2.3720(14)
2.4602(16)
2.6636(4)
1.261(8)
1.394(9)
1.465(9)
1.421(9)
1.350(9)
2.035(6)
2.079(4)
2.3690(13)
2.3909(13)
2.4755(15)
2.6598(4)
1.251(7)
1.357(8)
1.475(8)
1.436(8)
1.353(8)
Ir(1A)AC(1A)
Ir(1A)AO(1A)
Ir(1A)AP(1A)
Ir(1A)AP(2A)
Ir(1A)AI(1A)
Ir(1A)AI(2A)
O(1A)AC(3A)
C(1A)AC(2A)
C(1A)AC(5A)
C(2A)AC(3A)
C(5A)AC(6A)
Ir(1B)AC(1B)
Ir(1B)AO(1B)
Ir(1B)AP(1B)
Ir(1B)AP(2B)
Ir(1B)AI(1B)
Ir(1B)AI(2B)
O(1B)AC(3B)
C(1B)AC(2B)
C(1B)AC(5B)
C(2B)AC(3B)
C(5B)AC(6B)
2.057(7)
2.097(4)
2.3688(17)
2.3739(16)
2.6639(5)
2.7563(5)
1.263(7)
1.375(9)
1.452(9)
1.427(9)
1.359(9)
2.051(6)
2.088(4)
2.3709(16)
2.3780(16)
2.6668(5)
2.7764(5)
1.262(7)
1.373(9)
1.440(9)
1.436(9)
1.352(8)
IrAAIA
O(A)AC(3A)
C(1A)AC(2A)
C(1A)AC(5A)
C(2A)AC(3A)
C(5A)AC(6A)
IrBAC(1B)
IrBAO(1B)
IrBAP(1B)
IrBAP(2B)
IrBAClB
IrBAIB
O(1B)AC(3B)
C(1B)AC(2B)
C(1B)AC(5B)
C(2B)AC(3B)
C(5B)AC(6B)
Bond angles
C(3A)AO(1A)AIrA
C(2A)AC(1A)AC(5A)
C(2A)AC(1A)AIrA
C(5A)AC(1A)AIrA
C(1A)AC(2A)AC(3A)
O(1A)AC(3A)AO(2A)
O(1A)AC(3A)AC(2A)
O(2A)AC(3A)AC(2A)
C(6A)AC(5A)AC(1A)
C(5A)AC(6A)AC(13A)
C(5A)AC(6A)AC(7A)
C(13A)AC(6A)AC(7A)
C(3B)AO(1B)AIrB
112.0(4)
121.8(6)
C(3A)AO(1A)AIr(1A)
C(2A)AC(1A)AC(5A)
C(2A)AC(1A)AIr(1A)
C(5A)AC(1A)AIr(1A)
C(1A)AC(2A)AC(3A)
O(1A)AC(3A)AO(2A)
O(1A)AC(3A)AC(2A)
O(2A)AC(3A)AC(2A)
C(6A)AC(5A)AC(1A)
C(5A)AC(6A)AC(7A)
C(5A)AC(6A)AC(13A)
C(7A)AC(6A)AC(13A)
C(3B)AO(1B)AIr(1B)
C(2B)AC(1B)AC(5B)
C(2B)AC(1B)AIr(1B)
C(5B)AC(1B)AIr(1B)
C(1B)AC(2B)AC(3B)
O(1B)AC(3B)AO(2B)
O(1B)AC(3B)AC(2B)
O(2B)AC(3B)AC(2B)
C(6B)AC(5B)AC(1B)
C(5B)AC(6B)AC(7B)
C(5B)AC(6B)AC(13B)
C(7B)AC(6B)AC(13B)
111.4(4)
122.2(6)
112.1(5)
125.7(5)
114.9(6)
120.0(6)
121.5(6)
118.5(6)
129.5(7)
123.9(7)
119.6(6)
116.5(6)
112.5(4)
121.9(6)
112.3(5)
125.8(5)
115.0(6)
121.4(6)
120.3(6)
118.3(6)
130.7(6)
122.9(6)
121.6(6)
115.4(6)
111.5(4)
126.7(5)
115.1(6)
120.6(6)
120.8(6)
118.6(6)
129.5(6)
120.0(6)
124.2(6)
115.8(6)
112.2(4)
121.9(5)
113.4(4)
124.7(4)
113.9(5)
120.5(5)
120.9(5)
118.6(5)
128.6(6)
121.3(6)
122.7(6)
115.9(5)
C(2B)AC(1B)AC(5B)
C(2B)AC(1B)AIrB
C(5B)AC(1B)AIrB
C(1B)AC(2B)AC(3B)
O(1B)AC(3B)AO(2B)
O(1B)AC(3B)AC(2B)
O(2B)AC(3B)AC(2B)
C(6B)AC(5B)AC(1B)
C(5B)AC(6B)AC(13B)
C(5B)AC(6B)AC(7B)
C(13B)AC(6B)AC(7B)
4. Experimental
gon 1000 spectrometer. NMR spectra were obtained on
either a Bruker DRX 400 or a Bruker Avance 300 at
1
4.1. General procedures and instruments
25 ꢁC. For the Bruker DRX 400, H, 13C and 31P NMR
spectra were obtained operating at 400.1 (1H), 100.6 (13C)
and 162.0 (31P) MHz, respectively. For the Bruker Avance
Standard laboratory procedures were followed as have
been described previously [16]. The compound Ir[C8H5-
(Ph-3)]Cl(PPh3)2 was prepared either by the literature
method [3] or by the improved preparation described in
Section 4.2, below. IrHCl2(PPh3)3 [17] and Hg(CH@CPh2)2
[18] were prepared according to the reported procedures.
Infrared spectra (4000–400 cmꢀ1) were recorded as
Nujol mulls between KBr plates on a Perkin–Elmer Para-
1
300, H, 13C, and 31P NMR spectra were obtained operat-
ing at 300.13 (1H), 75.48 (13C) MHz, and 121.50 (31P)
MHz, respectively. Resonances are quoted in ppm and
1H NMR spectra referenced to either tetramethylsilane
(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%

A. Bierstedt et al. / Journal of Organometallic Chemistry 691 (2006) 3846–3852
3851
orthophosphoric acid (0.00 ppm) as an external standard.
Mass spectra were recorded using the fast atom
bombardment technique with a Varian VG 70-SE mass
spectrometer. Elemental analyses were obtained from the
Microanalytical Laboratory, University of Otago.
conc. HCl (0.2 mL) was added dropwise to the reaction
mixture and heating under reflux continued for 90 min.
After cooling to room temperature solid NaHCO3 was
added to neutralize the excess acid. This mixture was fil-
tered through Celite and dried over MgSO4. The solvent
was removed from this dried solution under vacuum. The
resulting red oil was purified by chromatography on silica
gel using dichloromethane as eluent. The red-orange band
was collected and the solid obtained from this was recrys-
tallised from CH2Cl2/ethanol to give pure 2 as a red-orange
microcrystalline solid (84 mg, 74%). m/z 1142.12391;
C54H4535ClI193IrO2P2 requires 1142.12575. Anal. Calc. for
C54H45ClIIrO2P2: C, 56.77; H, 3.97. Found: C, 56.62; H,
3.91%. IR (cmꢀ1): 1714(w), 1548(m), 1262(m), 1188(m),
1157(w), 1091(s), 1029(w), 820(w), 746(m), 697(s). 1H
NMR (see ring-numbering scheme in Chart 1) (CDCl3,
d): 2.66 (s, 3H, OCH3), 5.04 (s, 1H, H(4)), 6.11–7.26 (m,
28H, CHaromatic), 7.55 (s, 1H, CH@CPh2), 7.94–8.00 (m,
4.2. Improved preparation of Ir[C8H5(Ph-3)]Cl(PPh3)2
A solution of IrHCl2(PPh3)3 (1.015 g, 1.00 mmol) and
Hg(CH@CPh2)2 (670 mg, 1.20 mmol) in dry benzene
(20 mL) was heated under reflux for 4 h. The reaction mix-
ture was then filtered through Celite to remove the precip-
itated material and the Celite washed with benzene. The
solvent was removed under vacuum and the product puri-
fied by recrystallisation from dichloromethane/ethanol to
give pure Ir[C8H5(Ph-3)]Cl(PPh3)2 as an orange solid
(614 mg, 66%). The spectral properties of this material were
identical to those published previously [3].
12H, CHaromatic). 13C NMR (CDCl3, d): 53.4 (s, OCH3),
2,4
4.3. Preparation of Ir[C8H5(Ph-3)]I(PPh3)2 (1)
119.6 (s, C(4)), 127.3 (t0,
J
= 9.2 Hz, o-C6H5P),
CP
127.7, 127.9, 128.2, 128.3 (s, aromatic C’s of the diphenyl-
1,3
To a solution of Ir[C8H5(Ph-3)]Cl(PPh3)2 (2.145 g,
2.31 mmol) in dichloromethane (50 mL) was added a solu-
tion of NaI (3.46 g, 23.1 mmol) in ethanol (20 mL) and
water (0.5 mL). The reaction mixture was stirred for
2.5 h. The resulting dark-red solution was dried with
Na2SO4, filtered and the solvent removed under vacuum.
Recrystallisation of the residue from dichloromethane/
ethanol gave pure 1 as a red crystalline solid (2.07 g,
88%). m/z 1022.1301 and 1020.1275; C50H40I193IrP2 and
C50H40I191IrP2 requires 1022.1279 and 1020.1256, respec-
tively. Anal. Calc. for C50H40IIrP2: C, 58.77; H, 3.95.
Found: C, 58.58; H, 3.96%. IR (cmꢀ1): 1185(w), 1156(w),
1092(m), 768(m), 742(m), 729(m), 693(s), 512(s). 1H
NMR (CDCl3, d): 6.06–7.37 (m, 40H, multiplet signals
not individually assigned from PPh3, iridaindeneH, and
vinyl group), 129.8 (s, p-C6H5P), 130.3 (t0,
J
=
CP
3,5
53.2 Hz, i-C6H5P), 135.7 (t0,
J
= 9.0 Hz, m-C6H5P),
CP
137.1 (s, CH@CPh2), 139.9 (s (quat.), ipso-C of the diphe-
nylvinyl group), 141.1 (s (quat.), ipso-C of the diphenylvi-
2
nyl group), 143.5 (s, @CPh2), 180.3 (t, JPC = 6.7 Hz,
C3), 188.5 (s, C5). 31P NMR (CDCl3, d): ꢀ18.44 (s).
4.5. Preparation of Ir[OC3H(CH@CPh2-3)-
(OMe-5)]I2(PPh3)2 (3)
Ir[C8H5(Ph-3)]I(PPh3)2 (1) (102 mg, 0.1 mmol) was dis-
solved in dry dichloromethane (5 mL) which was degassed
by repeated freeze-pump-thaw cycles. This solution was
then heated to reflux and methyl propiolate (84 mg,
10.0 mmol) added. The colour of the reaction mixture chan-
ged slowly from red to orange-yellow. After 15 min, 55% HI
(0.2 mL) was added dropwise to the reaction mixture and
heating under reflux continued for 30 min. After cooling
to room temperature solid NaHCO3 was added to neutral-
ize the excess acid. This mixture was filtered through Celite,
and dried over MgSO4. The solvent was removed from this
dried solution under vacuum. The resulting red oil was puri-
fied by chromatography on silica gel using dichlorometh-
ane/hexane (1:1) as eluent. The red-orange band was
collected and the solid obtained from this was recrystallised
from CH2Cl2/ethanol to give pure 3 as a red-orange micro-
crystalline solid (61 mg, 50%). m/z, 1105.15470 and
Ph substituent on iridaindene). 13C NMR (CDCl3, d):
2,4
127.5 (t0 [16],
J
= 10.1 Hz, o-C6H5P), 129.8 (s, p-
CP
1,3
C6H5P), 130.6 (t0,
J
= 55.6 Hz, i-C6H5P), 135.1 (t0,
CP
3,5
J
= 10.8 Hz, m-C6H5P); singlet signals all CH, not
CP
individually assigned, at 121.8, 122.0, 123.6, 125.4, 127.1,
127.3, from C’s of iridaindene six-membered ring and Ph
2
substituent on iridaindene; 131.4 (t, JCP = 8.3 Hz, irida-
indene C2H), 139.0 (s, quat. C, unassigned), 142.4 (t,
2
2JCP = 6.8 Hz, iridaindene CIr), 154.1 (t, JCP = 3.4 Hz,
quat. C, unassigned), 154.9 (s, quat. C, unassigned). 31P
NMR (CDCl3, d): 23.17 (s).
4.4. Preparation of Ir[OC3H(CH@CPh2-3)-
(OMe-5)]ClI(PPh3)2 (2)
1107.15434; C54H45 I
35 191IrO2P2 requires 1105.15456
[M ꢀ I]+ and C54H4535I193IrO2P2 requires 1107.15690
[M ꢀ I]+. Anal. Calc. for C54H45I2IrO2P2: C, 52.56; H,
3.68. Found: C, 52.33; H, 3.82%. IR (cmꢀ1): 1549(s),
1261(m), 1205(m), 1086(s), 1037(s), 747(m), 722(m),
Ir[C8H5(Ph-3)]I(PPh3)2 (1) (102 mg, 0.1 mmol) was dis-
solved in dry dichloromethane (5 mL) which was degassed
by repeated freeze-pump-thaw cycles. This solution was
then heated to reflux and methyl propiolate (84 mg,
10.0 mmol) added. The colour of the reaction mixture
changed slowly from red to orange-yellow. After 15 min,
1
692(s). H NMR (see ring-numbering scheme in Chart 1)
(CDCl3, d): 2.55 (s, 3H, OCH3), 4.94 (s, 1H, H(4)), 6.11–
7.28 (m, 28H, CHaromatic), 7.63 (s, 1H, CH@CPh2), 7.99
(m, 12H, CHaromatic). 13C NMR (CDCl3, d): 53.4

3852
A. Bierstedt et al. / Journal of Organometallic Chemistry 691 (2006) 3846–3852
2,4
(s, OCH3), 119.1 (s, C(4)), 127.2 (t0,
J
= 9.8 Hz, o-
CP
(b) J.R. Bleeke, M.F. Ortwerth, A.M. Rohde, Organometallics 14
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C6H5P), 127.4, 127.7, 128.0, 128.2, 128.3 (s, aromatic C’s
of the diphenylvinyl group), 129.8 (s, p-C6H5P), 130.8 (s
very br, i-C6H5P), 136.1 (s br, m-C6H5P), 135.9 (s,
CH@CPh2), 140.0 (s (quat.), ipso-C of the diphenylvinyl
group), 141.1 (s (quat.), ipso-C of the diphenylvinyl group),
143.4 (s, @CPh2), 179.9 (t, 2JPC = 6.7 Hz, C3), 190.3 (s, C5).
31P NMR (CDCl3, d): ꢀ25.10 (s).
´
[4] F.M. Alıas, P.J. Daff, M. Paneque, M.L. Poveda, E. Carmona, P.J.
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4.6. X-ray crystal structure determinations for complexes 2
and 3
(c) P. DeShong, D.R. Sidler, P.J. Rybczynski, G.A. Slough, A.L.
Rheingold, J. Am. Chem. Soc. 110 (1988) 2575.
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X-ray intensities were recorded on a Siemens SMART
diffractometer with a CCD area detector using graphite
monochromated Mo Ka radiation (k = 0.71073 A) at 86
˚
(b) H. Werner, R. Weinand, H. Otto, J. Organomet. Chem. 307
(1986) 49;
or 83 K. Data were integrated and corrected for Lorentz
and polarisation effects using SAINT [19]. Semi-empirical
absorption corrections were applied based on equivalent
reflections using SADABS [20]. The structures were solved
by direct methods and refined by full-matrix least-squares
on F2 using programs SHELXS97 [21] and SHELXL97 [22]. All
non-hydrogen atoms were refined anisotropically. Hydro-
gen atoms were located geometrically and refined using a
riding model. Diagrams were produced using ORTEP-III
[23]. Both crystals contain two crystallographically inde-
pendent molecules which differ in the orientation of the phe-
nyl rings due to crystal packing effects. Crystal data and
refinement details for both structures are given in Table 1.
(c) W.A. Herrmann, M.L. Ziegler, O. Serhadll, Organometallics 2
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´
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Acknowledgements
[11] B.E. Woodworth, D.S. Frohnapfel, P.S. White, J.L. Templeton,
Organometallics 17 (1998) 1655.
[12] D.B. Grotjahn, J.M. Hoerter, J.L. Hubbard, J. Am. Chem. Soc. 126
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[13] M.I. Bruce, B.C. Hall, B.W. Skelton, A.H. White, N.N. Zaitseva, J.
Chem. Soc., Dalton Trans. (2000) 2279.
We thank the Marsden Fund administered by the Royal
Society of NZ for supporting this work and the Deutscher
Akademischer Austausch Dienst for supporting A.B.
[14] C.S. Chin, H. Lee, M.-S. Eum, Organometallics 24 (2005) 4849.
[15] M.I. Bruce, Chem. Rev. 91 (1991) 197.
Appendix A. Supplementary material
[16] S.M. Maddock, C.E.F. Rickard, W.R. Roper, L.J. Wright, Organo-
metallics 15 (1996) 1793.
[17] S.E. Landau, K.E. Groh, A.J. Lough, R.H. Morris, Inorg. Chem. 41
(2002) 2995.
[18] (a) V.I. Sokolov, V.V. Bashilov, O.A. Reutov, J. Organomet. Chem.
162 (1978) 271;
(b) M.G. Moloney, J.T. Pinhey, J. Chem. Soc., Perkin Trans. I (1988)
2847.
[19] SAINT, Area Detector Integration Software, Siemens Analytical
Instruments Inc., Madison, WI, USA, 1995.
[20] G.M. Sheldrick, SADABS, Program for Semi-empirical Absorption
Correction, University of Go¨ttingen, Go¨ttingen, Germany, 1997.
[21] G.M. Sheldrick, SHELXS97, Program for Crystal Structure Determi-
nation, University of Go¨ttingen, Go¨ttingen, Germany, 1977.
[22] G.M. Sheldrick, SHELXL97, Program for Crystal Structure Refine-
ment, University of Go¨ttingen, Go¨ttingen, Germany, 1997.
[23] M.N. Burnett, C.K. Johnson, ORTEP-III: Oak Ridge Thermal Ellip-
soid Plot Program for Crystal Structure Illustrations, Oak Ridge
National Laboratory Report ORNL-6895, 1996.
Crystallographic data (excluding structure factors) for 2
and 3 have been deposited with the Cambridge Crystallo-
graphic Data Centre as Supplementary Publication Nos.
CCDC 299550 and 299551, respectively. Copies of this
information can be obtained free of charge from the Direc-
tor, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
(fax: +44 1223 336 033; e-mail: deposit@ccdc.cam.ac.uk
or http://www.ccdc.cam.ac.uk). Supplementary data asso-
ciated with this article can be found, in the online version,
at doi:10.1016/j.jorganchem.2006.05.035.
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