Preparation of hydrido(vinyl)iridium(III) complexes from functionalized olefins by C-H activation

Article abstract of DOI:10.1139/V05-234

The four-coordinate iridium(I) precursor trans-[IrCl(N₂) (PPh₃)₂] (1) reacts with functionalized olefins RCH=C(R′)C(O)R″ by displacement of the dinitrogen ligand and oxidative addition of the C-H bond to the metal center t

Full text of DOI:10.1139/V05-234

205
Preparation of hydrido(vinyl)iridium(III) complexes
from functionalized olefins by C—H activation1
Bernd Papenfuhs, Thomas Dirnberger, and Helmut Werner
Abstract: The four-coordinate iridium(I) precursor trans-[IrCl(N2)(PPh3)2] (1) reacts with functionalized olefins
RCH=C(R′)C(O)R′′ by displacement of the dinitrogen ligand and oxidative addition of the C—H bond to the metal
center to give six-coordinate hydrido(vinyl)iridium(III) complexes [IrH(Cl){κ2(C,O)-C(R)=C(R′)C(R′′)=O}(PPh3)2] (2–
12) in good to excellent yields. The reaction of [IrH(Cl){κ2(C,O)-CH=CHC(Me)=O}(PPh3)2] (2) with AgClO4 affords
the cationic compound [IrH{κ2(C,O)-CH=CHC(Me)=O}(PPh3)2]ClO4 (15), which in solution equilibrates with the un-
charged isomers [IrH(OClO3){κ2(C,O)-CH=CHC(Me)=O}(PPh3)2] (15a and 15b). In contrast, five-coordinate [IrH{κ2-
(C,O)-CH=CHC(Et)=O}(PPh3)2]ClO4 (16), prepared from 3 and AgClO4, is stable and undergoes addition reactions
with CO, PPh3, C2H4, CH3CϵCH, MeCN, and PhCN to give the six-coordinate complexes [IrH(L){κ2(C,O)-CH=CHC-
(Et)=O}(PPh3)2]ClO4 (17–22). The neutral hydrido(thiolato) compound [IrH(SPh){κ2(C,O)-CH=CHC(Et)=O}(PPh3)2]
(23) was obtained on treatment of 21 with NaSPh.
Key words: iridium, C—H activation, hydrido complexes, vinyl complexes, phosphine complexes.
Résumé : Le précurseur tétracoordiné de l’iridium(I), trans-[IrCl(N2)(PPh3)2] (1), réagit avec les oléfines fonctionnali-
sées RCH=C(R′)C(O)R′′ par déplacement du ligand diazote et par addition oxydante de la liaison C—H du centre mé-
tallique pour conduire à la formation des complexes hexacoordinés hydrido(vinyl)iridium(III) [IrH(Cl){κ2(C,O)-C(R)=
C(R′)C(R′′)=O}(PPh3)2] (2–12) avec de bons rendements. La réaction du [IrH(Cl){κ2(C,O)-CH=CHC(Me)=O}(PPh3)2]
(2) avec du AgClO4 conduit à la formation du composés cationique [IrH{κ2(C,O)-CH=CHC(Me)=O}(PPh3)2]ClO4 (15)
qui s’équilibre en solution avec formation des isomères non chargés [IrH(OClO3){κ2(C,O)-CH=CHC(Me)=O}(PPh3)2]
(15a and 15b). Par opposition, le composé pentacoordiné [IrH{κ2(C,O)-CH=CHC(Et)=O}(PPh3)2]ClO4 (16) qui a été
préparé à partir du composé 3 et de AgClO4 est stable et il donne des réactions d’additions avec le CO, le PPh3, le
C2H4, le CH3CϵCH, le MeCn et le PhCN pour conduire à la formation de complexes hexacoordinés [IrH(L){κ2(C,O)-
CH=CHC(Et)=O}(PPh3)2]ClO4 (17–22). Le traitement du composé 21 avec du NaSPh conduit à la formation du com-
posé neutre [IrH(SPh){κ2(C,O)-CH=CHC(Et)=O}(PPh3)2] (23).
Mots clés : iridium, activation de C—H, complexes hydrido, complexes de vinyle, complexes de phosphine.
[Traduit par la Rédaction] Papenfuhs et al. 213
Introduction
used as the precursors, UV irradiation in benzene leads to a
quantitative conversion to the six-coordinate isomers
[IrH(Cl){κ2(C,O)-C(R)=CH(OMe)=O}(P-i-Pr3)2] in which
the hydrido(vinyl)iridium moiety is stabilized by an addi-
tional linkage of one C=O group to the metal center (2).
The present paper describes a synthetic protocol for a se-
ries of neutral and cationic hydrido(vinyl)iridium(III) com-
plexes with Ir(PPh3)2 as a building block in which the
substituted vinyl group also behaves as a bidentate ligand.
Due to this coordination mode, the order of thermodynamic
As part of our investigations on the reactivity of low-
valent iridium complexes containing alkenes and alkynes as
ligands, we reported (1) that upon low-temperature UV irra-
diation in toluene the four-coordinate ethene derivative
trans-[IrCl(C2H4)(P-i-Pr3)2] partly rearranges to the five-
coordinate hydrido(vinyl) isomer [IrH(Cl)(CH=CH2)(P-i-
Pr3)2]. This compound is thermodynamically unstable and
on warming to room temperature reconverts to the starting
material. If, however, instead of the ethene complex trans-
[IrCl(C2H4)(P-i-Pr3)2] the related methyl acrylate and dimethyl
fumarate derivatives trans-[IrCl(CH2=CHCO2Me)(P-i-Pr3)2]
and trans-[IrCl{(E)-CH(CO2Me)=CH(CO2Me)}(P-i-Pr3)2] are
2
stability [Ir](H)(CH=CHR) < [Ir](η -CH2=CHR), found by
Bergman (3) and Perutz (4) and their co-workers for [Ir] =
5
5
(η -C5Me5)Ir(PMe3) and (η -C5H5)Ir(C2H4), is reversed and
the hydrido(vinyl) compounds can be isolated as stable enti-
Received 16 June 2005. Published on the NRC Research Press Web site at http://canjchem.nrc.ca on 28 February 2006.
This paper is dedicated to Professor Arthur J. Carty, in recognition of his manifold and important contributions to organometallic
chemistry.
H. Werner,2 B. Papenfuhs, and T. Dirnberger. Institut für Anorganische Chemie der Universität, Am Hubland, D-97074
Würzburg, Germany.
1This article is part of a Special Issue dedicated to Professor Arthur Carty.
2Corresponding author (e-mail: helmut.werner@mail.uni-wuerzburg.de).
Can. J. Chem. 84: 205–213 (2006)
doi:10.1139/V05-234
© 2006 NRC Canada

206
Can. J. Chem. Vol. 84, 2006
Scheme 1.
R
O
L
Ir
L
Ir
H
H
Cl
Cl
O
R
Me
L
L
2 - 4
5 - 8
O
R
O
R
Me
- N2
- N2
R
R
Me
Et
Ph
2
3
4
OMe
Me
Ph
L
5
6
7
8
Ir
N2
Cl
L
CO2Me
1
- N2
Me
- N2
O
Me
Ph
O
Ph
O
Me
Ph
Et
L
Ir
L
L
Ir
L
Me
Et
H
H
Cl
Cl
Ph
O
9
10
(L = PPh3)
ties. Some preliminary results related to this study have al-
ready been communicated (5).
group to the metal center, an octahedral geometry for com-
pounds 2–4 (as shown in Scheme 1) can be assumed. The 1H
NMR spectra of 2–4 display two doublets at about δ 9.60
and 6.20 (for 2 and 3) and δ 9.97 and 6.86 (for 4), which in
agreement with results by Nesmeyanov et al. (8) and one of
us (9) are assigned to the vinylic protons in α and β posi-
tions. For the hydrido ligand, there appears in the high-field
region a triplet resonance at, respectively, δ –22.42 (for 2),
–22.55 (for 3), and –21.88 (for 4), which is split into a trip-
Results and discussion
The dinitrogen complex trans-[IrCl(N2)(PPh3)2] (1), pre-
pared by Collman and Kang (6) from trans-[IrCl(CO)-
(PPh3)2] and benzoyl azide, reacts in benzene with the
Michael acceptors CH2=CHC(O)R (R = Me, Et, Ph) to give
the six-coordinate hydrido(vinyl)iridium(III) compounds 2–4
in about 80%–90% yield (Scheme 1). Although the displace-
ment of the dinitrogen ligand proceeds slowly at room tem-
1
let owing to H–31P coupling. Since the chemical shift of
these signals is quite similar to that of the
bis(triisopropylphosphine) complex [IrH(Cl){κ2(C,O)-
C(CO2Me)=CHC(OMe)=O}(P-i-Pr3)2], which has been char-
acterized crystallographically (10), we assume that the
hydrido ligand is trans to the oxygen and not to the carbon
atom of the chelate ring. The observation of only one signal
in the 31P NMR spectra of 2–4 confirms that the phosphine
ligands are trans disposed. The 13C NMR spectrum of 2 dis-
plays the signals for the vinyl carbon atoms at δ 197.3 and
133.1 ppm. Due to the cis disposition of the α-C atom and
the PPh3 groups, the signal at δ 197.3 ppm is split into a trip-
let, while the resonance at δ 133.1 ppm appears as a singlet.
The starting material 1 not only reacts with the ketones
CH2=CHC(O)R (R = Me, Et, Ph), but also with the related
derivatives RCH=CHC(O)Me (R = OMe, Me, Ph, CO2Me),
MeCH=C(Me)C(O)Et, and PhCH=CHC(O)Ph to give the
corresponding hydrido(vinyl)iridium(III) complexes 5–10 in
good to excellent yields. These reactions are considerably
slower than those leading to 2–4, and thus the corresponding
reaction mixture has to be stirred for 18 h at 80 °C in tolu-
ene. In contrast to the conditions employed to obtain 2–7,
for the preparation of 8–10 an excess of the olefinic sub-
2
perature, attempts to detect the olefin species trans-[IrCl{η -
CH2=CHC(R)=O}(PPh3)2], supposed to be generated in one
of the initial steps of the reaction, by NMR spectroscopy
failed. Nevertheless, we assume that these compounds are
formed as intermediates but presumably are short-lived and
react by intramolecular C—H activation to give the thermo-
dynamically more stable products. In this context we note
that recently Esteruelas, Oro, and co-workers (7) reported the
preparation of the four-coordinate iridium(I) complex [Ir(κ2-
2
acac){η -CH2=CHC(O)Me}(PCy3)] from [Ir(κ2-acac)(C8H14)-
(PCy3)] and methyl(vinyl) ketone, which is stable and upon
heating rearranges to a mixture of two six-coordinate
hydrido(vinyl)iridium(III) stereoisomers.
The hydrido(vinyl) complexes 2–4 are yellow or orange
solids, which are not air-sensitive and readily soluble in
common polar organic solvents. A characteristic feature in
the IR spectra of 2–4 is the ν(C=O) stretching mode at
1525–1550 cm–1, which is shifted by ca. 120–150 cm–1 to
lower wavenumbers compared with the free ketones. Since
this shift is consistent with a coordination of the carbonyl
© 2006 NRC Canada

Papenfuhs et al.
207
Scheme 2.
strate has to be used. If the dinitrogen complex 1 was treated
with an equimolar amount of MeCH=C(Me)C(O)Et, the car-
bonyl iridium(I) compound trans-[IrCl(CO)(PPh3)2] (11) is
generated as the dominant product. With regard to the for-
mation of 8 from 1 and MeC(O)CH=CHCO2Me, the remark-
able feature is that the oxidative addition of the C—H bond
adjacent to the CO2Me functionality occurs exclusively.
Moreover, it is worth mentioning that upon treatment of 1
with PhCH=CHC(O)Ph only the activation of the olefinic
C—H and not that of an aromatic C—H bond is observed.
The reactivity of 1 is thus different to that of the bis(tri-
isopropylphosphine)iridium(I) derivative trans-[IrCl(C8H14)-
(P-i-Pr3)2], which reacts with PhCH=CHC(O)Ph to give a
1:1 mixture of the two isomers [IrH(Cl){κ2(C,O)-
O
L
Ir
H
OMe
- N2
Cl
O
OMe
L
L
11
Ir
N2
Cl
L
O
1
L
Ir
NH2
- N2
H
Cl
O
NH2
L
C(Ph)=CHC(Ph)=O}(P-i-Pr3)2]
and
[IrH(Cl){κ2(C,O)-
12
C6H4C(CH=CHPh)=O}(P-i-Pr3)2] (12). The 13C NMR spec-
trum of 10 displays a triplet resonance at δ 215.0 (with
2J(PC) = 6.1 Hz), which appears at a similar chemical shift
(δ 209.4, 2J(PC) = 5.3 Hz) as that of [IrH(Cl){κ2(C,O)-
C(Ph)=CHC(Ph)=O}(P-i-Pr3)2] (12) and thus supports the
proposed structure.
(L = PPh3)
wavenumbers compared with the coordinatively unsaturated
compound 13. The hydride signal appears in the H NMR
spectrum of 14 at δ –19.09 and is thus shifted by ca. 2.3 ppm
to lower fields compared with 13.
1
Similarly to the Michael acceptors used for the prepara-
tion of 2–10, methyl acrylate and acrylic acidamide also re-
act with the dinitrogen compound 1 to afford the air-stable
hydrido(vinyl) complexes 11 and 12 in 66% and 89% yield,
respectively (Scheme 2). The IR spectrum of 12 shows the
band for the ν(C=O) stretching mode at 1555 cm–1, which is
The reaction of 2 with AgClO4 was carried out under sim-
ilar conditions as with AgPF6 and resulted in the formation
of the hydrido(vinyl) complex 15 (Scheme 4). While the
poor solubility of 15 in hydrocarbons is in agreement with
the formulation as an ionic compound analogous to 13, the
molar conductivity (Λ) in nitromethane (36 cm2 Ω–1 mol–1)
is considerably lower than expected for a 1:1 electrolyte (see
14: Λ = 65 cm2 Ω–1 mol–1). The 31P NMR spectrum of 15 in
CDCl3 at room temperature shows two singlets at δ 23.1
(sharp) and δ 17.5 (broad), which after decoupling change
into doublets. In CD2Cl2 at –80 °C three doublets appear,
two of which collapse to a broadened resonance after in-
creasing the temperature to 0 °C. Although these results
have to be interpreted with caution, we assume that in solu-
tion an equilibrium between the cationic species 15 and the
uncharged isomers 15a and 15b exists. It is well-known that
not only for iridium (14), but also for various other transi-
tion metals (15), the perchlorate anion can behave as a
weakly coordinated (“noninnocent”) ligand that is readily re-
placed by better nucleophiles. It should be mentioned that
1
at nearly the same position as for 2 and 3. In the H NMR
spectra of 11 and 12, the hydride resonance appears at
δ –25.07 (11) and δ –24.19 (12) and is significantly shifted
upfield compared with 2–10. We assume that this shift is due
to the stronger electron-donating effect of the OMe and NH2
functionalities compared with that of the alkyl and phenyl
groups. The reaction of 1 with acrylonitrile does not lead to
a stable iridium(I) or iridium(III) complex, but yields a pale
yellow solid, which, according to the IR spectrum, presum-
ably is a polymer with terminal CH2CN and CH(CH3)CN
groups (13).
To obtain a coordinatively unsaturated hydrido(vinyl)irid-
ium(III) compound, considered to be a potential precursor
for addition/insertion reactions, we attempted to eliminate
the chloro ligand from 2 by using AgPF6 and AgClO4, re-
spectively. The reaction of 2 with AgPF6 in dichloromethane
is quite rapid at room temperature and yields, after separa-
tion of AgCl and chromatographic workup of the solution, a
1
the H NMR spectrum of the product obtained from 2 and
AgClO4 also displays two sets of signals for the =CH, CH3,
and IrH protons, which is in agreement with the equilibrium
between 15 and the nonionic species 15a and 15b.
1
brownish solid that owing to the H and 31P NMR spectra
consists mainly (ca. 90%) of the expected compound
[IrH{κ2(C,O)-CH=CHC(Me)=O}(PPh3)2]PF6 (13). Attempts
to separate the by-products by fractional crystallization or
repeated column chromatography failed. Typical spectro-
Similarly to 2, the corresponding iridium(III) counterpart
3 reacts with AgClO4 in CH2Cl2 to give the cationic com-
plex 16 (Scheme 5), which, however, appears to have no ten-
1
dency to coordinate the perchlorate anion. The H as well as
1
the 31P NMR spectrum of 16 shows only one sharp reso-
nance for the IrH proton and the phosphine ligands, respec-
tively, and these resonances do not broaden or split into two
signals by decreasing the temperature. We note that the
scopic data of 13 are the H NMR resonances for the vinylic
protons at δ 9.73 and 6.02 (see 2: δ 9.58 and 6.18), the hy-
dride signal at δ –21.38 (see 2: δ –22.42), and the singlet in
the 31P NMR spectrum at δ 21.7 (see 2: δ 14.7). Treatment
of 2 with AgPF6 in the presence of CO gave the cationic six-
coordinate hydrido(vinyl)iridium(III) carbonyl 14 (Scheme 3)
for which a correct elemental analysis was obtained. The IR
spectrum of 14 (being an off-white, air-stable solid) displays
a strong band for the CO ligand at 2060 cm–1 and a medium-
to-strong absorption for the ν(C=O) stretching mode at
1580 cm–1. The latter is shifted by 30 cm–1 to higher
1
chemical shifts of the signals observed in the H and 31P
NMR spectra of 16 are nearly identical to those assigned to
the cation of 15, and thus we are convinced that the pro-
posed structure with a five-coordinate metal center is cor-
rect.
The open coordination site in the cation of 16 can easily
be occupied by CO, PPh3, ethene, propyne, acetonitrile, and
© 2006 NRC Canada

208
Can. J. Chem. Vol. 84, 2006
Scheme 3.
L
Ir
L
H
AgPF6
AgPF6
CO
Cl
O
Me
2
PF6
L
Ir
L
L
Ir
L
PF6
H
H
CO
O
Me
O
Me
13
14
(L = PPh3)
+ by-products
Scheme 4.
L
Ir
L
H
O3ClO
O
Me
ClO4
L
Ir
L
L
15a
H
AgClO4
Ir
L
H
Cl
O
Me
O
Me
L
15
2
O3ClO
Ir
L
H
O
Me
(L = PPh3)
15b
Scheme 5.
ClO4
ClO4
L
Ir
L
L
L
Ir
L
H
H
L'
AgClO4
L'
Ir
L
H
Cl
O
Et
O
Et
O
Et
17 - 22
L'
16
3
L'
CO
MeC CH
MeCN
17
18
19
20
(L = PPh3)
PPh3
C2H4
21
22
PhCN
benzonitrile. With the exception of 19, the related
hydrido(vinyl)iridium(III) compounds 17, 18, and 20–22 are
exceedingly stable and decompose between 112 (20) and
179 °C (21). Owing to the ionic nature, they are soluble in
acetone, nitromethane, CH2Cl2, and CHCl3, but almost in-
soluble in benzene and other hydrocarbons. Conductivity
measurements confirm the presence of 1:1 electrolytes. The
ethene complex 19 is only stable under a C2H4 atmosphere
the singlet resonance for the 31P NMR nuclei at δ 13.9, the
latter being shifted upfield by 8.6 ppm compared with 16.
When we attempted to remove the volatiles and isolate com-
pound 19, the precursor 16 was regenerated.
In contrast to 19, the analogous propyne complex 20 is
rather inert and neither undergoes an insertion of the
alkyne ligand into the Ir—H bond nor rearranges to the
vinylidene isomer [IrH(=C=CHCH3){κ2(C,O)-CH=CHC-
(Et)=O}(PPh3)2]ClO4 (16). However, compound 20, as well as
the nitrile iridium(III) analogues 21 and 22, smoothly react
with CO to afford the corresponding carbonyl complex 17.
1
and has been characterized by H and 31P NMR spectros-
1
copy. Typical features of 19 are the H NMR signal for the
3
ethene protons at δ 3.55 (triplet with J(PH) = 3.1 Hz) and
© 2006 NRC Canada

Papenfuhs et al.
209
Scheme 6.
benzene–hexane (1:1), and the solution chromatographed on
Al2O3 (neutral, activity grade V, length of column 6 cm).
With benzene–hexane (1:1) a yellow fraction was eluted,
which was brought to dryness in vacuo. The remaining yel-
low, air-stable solid was washed twice with 5 mL portions
of hexane (30 °C) and dried. Yield: 78 mg (80%), mp
184 °C (dec.). IR (KBr, cm–1): 2190 ν(IrH), 1550 ν(C=O).
1H NMR (90 MHz, CDCl3) δ: 9.58 (d, 1H, J(HH) = 7.5 Hz,
IrCH), 7.59–7.19 (m, 30H, C6H5), 6.18 (d, 1H, J(HH) =
7.5 Hz, IrCH=CH), 1.53 (t, 3H, J(PH) = 1.4 Hz, CH3),
–22.42 (t, 1H, J(PH) = 16.4 Hz, IrH). 13C NMR (50.3 MHz,
CDCl3) δ: 208.0 (s, C=O), 197.3 (t, J(PC) = 7.0 Hz, IrCH),
133.1 (s, IrCH=CH), 134.3 (vt, N = 11.6 Hz, ortho-C of
PC6H5), 131.9 (vt, N = 54.7 Hz, ipso-C of PC6H5), 129.6 (s,
para-C of PC6H5), 127.7 (vt, N = 10.1 Hz, meta-C of
PC6H5), 24.0 (s, C(O)CH3). 31P NMR (36.2 MHz, CDCl3) δ:
14.7 (s, d in off-resonance). Anal. calcd. for C40H36ClIrOP2:
C 58.42, H 4.41; found: C 58.34, H 4.55.
L
ClO4
L
Ir
L
H
H
NaSPh
Ir
MeCN
PhS
O
Et
O
Et
L
(L = PPh3)
21
23
The acetonitrile ligand in 21 can not only be replaced by
CO but also by thiophenolate. The reaction of 21 with
NaSPh in THF proceeds slowly at room temperature and
gives the neutral hydrido(thiophenolato) complex 23 in 78%
yield (Scheme 6). 23 is an orange air-stable solid that has
been characterized by elemental analysis and spectroscopic
techniques. Attempts to also displace the acetonitrile ligand
in 21 by methyl xanthogenate, K[SC(S)OMe], led to the
formation of a mixture of compounds that could not be sepa-
rated by fractional crystallization or column chromatogra-
phy.
Preparation of [IrH(Cl){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2] (3)
In summarizing, the present work has shown that, pro-
vided the olefinic substrate RCH=CHR′ possesses a sub-
stituent R′ such as C(O)R, C(O)NH2, or C(O)OMe, the
reaction of the starting material trans-[IrCl(N2)(PPh3)2] (1)
with RCH=CHR′ leads preferentially to the hydrido(vinyl)-
iridium(III) complexes 2–12. These compounds are remark-
ably stable and neither thermally nor photochemically react
by intramolecular reductive elimination to give the four-
A solution of 1 (140 mg, 0.18 mmol) in 15 mL of toluene
was treated with ethyl(vinyl)ketone (18 µL, 0.18 mmol) and
stirred for 6 h at room temperature. The solvent was evapo-
rated in vacuo, the remaining yellow, air-stable solid was
washed twice with 5 mL portions of hexane (50 °C) and
dried. Yield: 137 mg (91%), mp 178 °C (dec.). IR (KBr, cm–1):
2
coordinate olefin iridium(I) isomers trans-[IrCl(η -
1
2240 ν(IrH), 1540 ν(C=O). H NMR (90 MHz, CDCl3) δ:
RCH=CHR′)(PPh3)2]. A rearrangement of this type does not
occur with the cationic species [IrH(L){κ2(C,O)-CH=CHC-
(R)=O}(PPh3)2]+, independent of whether the ligand L is a
good σ donor (MeCN, PhCN) or a destinctive π-acceptor
ligand (CO, CH3CϵCH). There is no doubt that the driving
9.60 (d, 1H, J(HH) = 7.6 Hz, IrCH), 7.58–7.28 (m, 30H,
C6H5), 6.21 (d, 1H, J(HH) = 7.6 Hz, IrCH=CH), 1.95 (q,
2H, J(HH) = 7.3 Hz, CH2CH3), 0.69 (t, 3H, J(HH) = 7.3 Hz,
CH2CH3), –22.55 (t, 1H, J(PH) = 16.5 Hz, IrH). 31P NMR
(36.2 MHz, CDCl3) δ: 13.6 (s, d in off-resonance). Anal.
calcd. for C41H38ClIrOP2: C 58.88, H 4.58; found: C 58.37,
H 4.51.
force for the formation of 2–12 from
1 and the
functionalized olefin is the formation of the chelating five-
membered IrC3O ring, which remains intact even in the pres-
ence of excess CO. In this context, we note that in contrast
to [IrH(Cl)(CH=CH2)(P-i-Pr3)2], the related hydrido(phenyl)
complex [IrH(Cl)(C6H5)(P-i-Pr3)2] is also quite stable and
reacts with CO by addition and not by reductive elimination
(17).
Preparation of [IrH(Cl){␬2(C,O)-CH=CHC(Ph)=O}-
(PPh3)2] (4)
A solution of 1 (140 mg, 0.18 mmol) in 15 mL of toluene
was treated with phenyl(vinyl)ketone (23 µL, 0.18 mmol)
and stirred for 18 h at room temperature. (Owing to the high
tendency of PhC(O)CH=CH2 to polymerize, preparation of
the ketone (18) in situ from β-chloropropiophenone is rec-
ommended). The reaction mixture was worked up analogous
to that described for 3. An orange, air-stable solid was ob-
tained. Yield: 134 mg (84%), mp 189 °C (dec.). IR
Experimental
All experiments were carried out under an atmosphere of
argon by using standard Schlenk techniques. The starting
material 1 was prepared as described in the literature (6). IR
spectra were recorded on a PerkinElmer 1420 IR spectrome-
ter and NMR spectra on Jeol FX 90 Q as well as Bruker AC
200 and Bruker AMX 400 instruments. Melting points (dec.
temp.) were determined by DTA. Conductivity measure-
ments were carried out in nitromethane with a Schott
Konduktometer CG 851. Abbreviations used: singlet (s),
doublet (d), triplet (t), quartet (q), multiplet (m), broadened
1
(KBr, cm–1): 2145 ν(IrH), 1525 ν(C=O). H NMR (90 MHz,
CDCl3) δ: 9.97 (d, 1H, J(HH) = 7.4 Hz, IrCH), 7.72–7.17
(m, 35H, PC6H5 and CC6H5), 6.86 (d, 1H, J(HH) = 7.4 Hz,
IrCH=CH), –21.88 (t, 1H, J(PH) = 16.5 Hz, IrH). 31P NMR
(36.2 MHz, CDCl3) δ: 13.4 (s, d in off-resonance). Anal.
calcd. for C45H38ClIrOP2: C 61.11, H 4.33; found: C 60.74,
H 4.35.
1
3
signal (br); N = J(PC) + J(PC).
Preparation of [IrH(Cl){␬2(C,O)-C(OMe)=CHC(Me)=O}-
(PPh3)2] (5)
A solution of 1 (140 mg, 0.18 mmol) in 15 mL of toluene
was treated with 4-methoxybut-3-en-2-one (18 µL,
0.18 mmol) and stirred for 18 h at 80 °C. After the solution
was cooled to room temperature, the solvent was evaporated
Preparation of [IrH(Cl){␬2(C,O)-CH=CHC(Me)=O}(PPh3)2] (2)
A solution of 1 (94 mg, 0.12 mmol) in 6 mL of benzene
was treated with methyl(vinyl)ketone (11 µL, 0.12 mmol)
and stirred for 2 h at room temperature. The solvent was
evaporated in vacuo, the residue was dissolved in 3 mL of
© 2006 NRC Canada

210
Can. J. Chem. Vol. 84, 2006
in vacuo, the remaining pale yellow, air-stable solid was
washed twice with 5 mL portions of hexane (50 °C) and
dried. Yield: 120 mg (78%), mp 226 °C (dec.). IR (KBr, cm–1):
0.79 (t, 3H, J(HH) = 7.3 Hz, CH2CH3), 0.75 (s, 3H,
=C(CH3)C), –21.91 (t, 1H, J(PH) = 16.1 Hz, IrH). 31P NMR
(36.2 MHz, CDCl3) δ: 11.7 (s, d in off-resonance). Anal.
calcd. for C43H42ClIrOP2: C 59.75, H 4.90; found: C 59.80,
H 4.68.
1
2175 ν(IrH), 1515 ν(C=O). H NMR (90 MHz, CDCl3) δ:
7.71–7.22 (m, 30H, C6H5), 5.17 (s, 1H, CHC(Me)=O), 2.54
(s, 3H, IrC(OCH3)=CH), 1.76 (s, 3H, C(CH3)=O), –21.92 (t,
1H, J(PH) = 16.0 Hz, IrH). 31P NMR (36.2 MHz, CDCl3) δ:
9.8 (s, d in off-resonance). Anal. calcd. for C41H38ClIrO2P2:
C 57.77, H 4.49; found: C 57.44, H 4.67.
Preparation of [IrH(Cl){␬2(C,O)-C(Ph)=CHC(Ph)=O}-
(PPh3)2] (10)
The procedure was analogous to that described for 5, us-
ing 1 (140 mg, 0.18 mmol) and benzylidenacetophenone
(75 mg, 0.36 mmol) as starting materials. An orange, air-
stable solid was obtained. Yield: 131 mg (76%), mp 212 °C
Preparation of [IrH(Cl){␬2(C,O)-C(Me)=CHC(Me)=O}-
(PPh3)2] (6)
1
The procedure was analogous to that described for 5, us-
ing 1 (140 mg, 0.18 mmol) and pent-3-en-2-one (17 µL,
0.18 mmol) as starting materials. A yellow, air-stable solid
was obtained. Yield: 125 mg (83%), mp 191 °C (dec.). IR
(dec.). IR (KBr, cm–1): 2160 ν(IrH), 1520 ν(C=O). H NMR
(90 MHz, CDCl3) δ: 7.96–6.62 (br m, 40H, C6H5), –21.43 (t,
1H, J(PH) = 16.4 Hz, IrH), signal of =CH proton probably
covered by the broad signal of phenyl protons. 13C NMR
(50.3 MHz, CDCl3) δ: 215.0 (t, J(PC) = 6.1 Hz, IrC), 199.3
(s, C=O), 144.7 (s, IrC(Ph)=CH), 136.9, 131.5, 131.0, 129.4,
128.5, 128.1, 126.7, 125.2 (all s, CC6H5), 134.7 (vt, N =
11.1 Hz, ortho-C of PC6H5), 131.4 (vt, N = 53.8 Hz, ipso-C
of PC6H5), 129.5 (s, para-C of PC6H5), 127.3 (vt, N =
10.2 Hz, meta-C of PC6H5). 31P NMR (36.2 MHz, CDCl3) δ:
10.3 (s, d in off-resonance). Anal. calcd. for C51H42ClIrOP2:
C 63.77, H 4.41; found: C 63.39, H 4.13.
1
(KBr, cm–1): 2200 ν(IrH), 1535 ν(C=O). H NMR (90 MHz,
CDCl3) δ: 7.78–7.23 (m, 30H, C6H5), 6.07 (s, 1H, CHC(Me)=O),
1.83 (s, 3H, C(CH3)=O), 0.92 (s, 3H, IrC(CH3)=CH), –22.67
(t, 1H, J(PH) = 16.4 Hz, IrH). 31P NMR (36.2 MHz, CDCl3)
δ: 11.6 (s, d in off-resonance). Anal. calcd. for C41H38ClIrOP2:
C 58.88, H 4.58; found: C 59.37, H 4.71.
Preparation of [IrH(Cl){␬2(C,O)-C(Ph)=CHC(Me)=O}-
(PPh3)2] (7)
Preparation of [IrH(Cl){␬2(C,O)-CH=CHC(OMe)=O}-
(PPh3)2] (11)
The procedure was analogous to that described for 5,
using 1 (140 mg, 0.18 mmol) and 4-phenylbut-3-en-2-one
(25 µL, 0.18 mmol) as starting materials. An orange, air-
stable solid was obtained. Yield: 133 mg (82%), mp 194 °C
A solution of 1 (94 mg, 0.12 mmol) in 6 mL of benzene
was treated with methyl acrylate (11 µL, 0.12 mmol) and
stirred for 2 h at 80 °C. After the solution was cooled to
room temperature, it was worked up analogously to that de-
scribed for 2. A yellow, air-stable solid was obtained. Yield:
67 mg (66%), mp 159 °C (dec.). IR (KBr, cm–1): 2205
1
(dec.). IR (KBr, cm–1): 2230 ν(IrH), 1540 ν(C=O). H NMR
(90 MHz, CDCl3) δ: 7.68–7.11 (m, 30H, PC6H5), 7.01–6.56
(m, 5H, CC6H5), 1.95 (t, 3H, J(PH) = 1.2 Hz, C(CH3)=O),
–22.10 (t, 1H, J(PH) = 15.9 Hz, IrH), signal of =CH proton
probably covered by signal of CC6H5 protons. 31P NMR
(36.2 MHz, CDCl3) δ: 10.7 (s, d in off-resonance). Anal.
calcd. for C46H40ClIrOP2: C 61.50, H 4.49; found: C 61.43,
H 4.37.
1
ν(IrH), 1580 ν(C=O). H NMR (90 MHz, CDCl3) δ: 9.17 (d,
1H, J(HH) = 8.7 Hz, IrCH), 7.66–7.24 (m, 30H, C6H5), 5.77
(d, 1H, J(HH) = 8.7 Hz, IrCH=CH), 3.15 (s, 3H, OCH3),
–25.07 (t, 1H, J(PH) = 16.1 Hz, IrH). 31P NMR (36.2 MHz,
CDCl3) δ: 14.7 (s, d in off-resonance). Anal. calcd. for
C40H36ClIrO2P2: C 57.30, H 4.33; found: C 57.68, H 4.11.
Preparation of [IrH(Cl){␬2(C,O)-C(CO2Me)=CHC(Me)=O}-
(PPh3)2] (8)
Preparation of [IrH(Cl){␬2(C,O)-CH=CHC(NH2)=O}-
(PPh3)2] (12)
The procedure was analogous to that described for 3, us-
ing 1 (107 mg, 0.14 mmol) and methyl-4-oxo-2-pentenoate
(24 mg, 0.28 mmol) as starting materials. An orange, air-
stable solid was obtained. Yield: 97 mg (79%), mp 228 °C
A solution of 1 (94 mg, 0.12 mmol) in 6 mL of benzene
was treated with methyl acrylate (9 mg, 0.12 mmol) and
stirred for 3 h at room temperature. The solvent was evapo-
rated in vacuo and the residue was recrystallized from di-
chloromethane–hexane (1:5) to give a white, air-stable solid.
Yield: 88 mg (89%), mp 181 °C (dec.). IR (KBr, cm–1):
3320, 3215 ν(NH), 2205 ν(IrH), 1555 ν(C=O). 1H NMR
(90 MHz, CDCl3) δ: 8.82 (d, 1H, J(HH) = 7.9 Hz, IrCH),
7.53–7.16 (m, 30H, C6H5), 5.57 (d, 1H, J(HH) = 7.9 Hz,
IrCH=CH), –24.19 (t, 1H, J(PH) = 16.8 Hz, IrH), signal for
NH2 protons not exactly located. 31P NMR (36.2 MHz,
CDCl3) δ: 13.6 (s, d in off-resonance). Anal. calcd. for
C39H35ClIrNOP2: C 56.89, H 4.28, N 1.70; found: C 56.96,
H 3.99, N 1.66.
1
(dec.). IR (KBr, cm–1): 2210 ν(IrH). H NMR (400 MHz,
CDCl3) δ: 7.59–6.81 (m, 30H, PC6H5), 2.89 (s, 3H,
CO2CH3), 2.03 (t, 3H, J(PH) = 1.2 Hz, C(CH3)=O), –22.89
(t, 1H, J(PH) = 16.0 Hz, IrH), signal of =CH proton proba-
bly covered by signal of C6H5 protons. 31P NMR (36.2 MHz,
CDCl3) δ: 11.5 (s, d in off-resonance). Anal. calcd. for
C42H38ClIrO3P2: C 57.30, H 4.35; found: C 57.49, H 4.46.
Preparation of [IrH(Cl){␬2(C,O)-C(Me)=C(Me)C(Et)=O}-
(PPh3)2] (9)
The procedure was analogous to that described for 5,
using 1 (140 mg, 0.18 mmol) and 4-methylhex-4-en-3-one
(69 µL, 0.54 mmol) as starting materials. A yellow, air-stable
solid was obtained. Yield: 123 mg (79%), mp 218 °C (dec.).
IR (KBr, cm–1): 2145 ν(IrH), 1550 ν(C=O). 1H NMR
(90 MHz, CDCl3) δ: 7.69–7.23 (m, 30H, PC6H5), 2.10 (q,
2H, J(HH) = 7.3 Hz, CH2CH3), 1.10 (s, 3H, IrC(CH3)=C),
Preparation of [IrH(CO){␬2(C,O)-CH=CHC(Me)=O}-
(PPh3)2]PF6 (14)
A solution of 2 (100 mg, 0.12 mmol) in 10 mL of di-
chloromethane was treated with AgPF6 (31 mg, 0.12 mmol)
© 2006 NRC Canada

Papenfuhs et al.
211
and stirred for 15 min at room temperature in the dark under
CO. After replacing the CO atmosphere for argon, the solu-
tion was filtered and the residue was washed twice with
1 mL portions of CH2Cl2. The filtrate was brought to dry-
ness in vacuo, the residue was dissolved in 6 mL of hexane–
CH2Cl2 (1:5), and the solution was chromatographed on
Al2O3 (neutral, activity grade V, length of column 5 cm). A
brownish fraction was eluted with hexane–CH2Cl2 (1:5) and
the solvent was evaporated in vacuo. After the residue was
recrystallized from CH2Cl2–hexane (1:5), an off-white, air-
stable solid was obtained. Yield: 105 mg (91%), mp 111 °C
(dec.). Conductivity (CH3NO2) Λ = 65 cm2 Ω–1 mol–1. IR
0.12 mmol) and AgClO4 (25 mg, 0.12 mmol) in 10 mL of
dichloromethane, was stirred for 15 min at room temperature
in the dark. The solution was filtered and a slow stream of
CO was passed through the filtrate for 1 min. The solvent
was evaporated in vacuo, the remaining yellow solid was
washed twice with 1 mL portions of CH2Cl2 and three times
with 5 mL portions of hexane and dried. Yield: 100 mg
(89%), mp 118 °C (dec.). Conductivity (CH3NO2) Λ =
56 cm2 Ω–1 mol–1. IR (KBr, cm–1): 2195 ν(IrH), 2040 ν(CO),
1
1575 ν(C=O). H NMR (200 MHz, CDCl3) δ: 9.42 (d, 1H,
J(HH) = 9.1 Hz, IrCH), 7.81–7.47 (m, 30H, PC6H5), 6.73
(dt, 1H, J(HH) = 6.9, J(PH) = 2.1 Hz, IrCH=CH), 1.80 (qt,
2H, J(HH) = 7.2, J(PH) = 2.4 Hz, CH2CH3), 0.53 (t, 3H,
J(HH) = 7.2 Hz, CH2CH3), –19.20 (t, 1H, J(PH) = 12.4 Hz,
IrH). 31P NMR (36.2 MHz, CDCl3) δ: 11.1 (s, d in off-
resonance). Anal. calcd. for C42H38ClIrO6P2: C 54.34, H
4.13; found: C 54.71, H 4.25.
1
(KBr, cm–1): 2190 ν(IrH), 2060 ν(CO), 1580 ν(C=O). H
NMR (90 MHz, CDCl3) δ: 9.47 (d, 1H, J(HH) = 9.2 Hz,
IrCH), 7.87–7.49 (m, 30H, PC6H5), 6.71 (d, 1H, J(HH) =
9.2 Hz, IrCH=CH), 1.23 (s, 3H, C(CH3)=O), –19.09 (t, 1H,
J(PH) = 12.5 Hz, IrH). 31P NMR (36.2 MHz, CDCl3) δ: 11.7
(s, d in off-resonance). Anal. calcd. for C41H36ClF6IrO2P3: C
51.30, H 3.78; found: C 51.52, H 3.67.
Preparation of [IrH{␬2(C,O)-CH=CHC(Et)=O}(PPh3)3]-
ClO4 (18)
Preparation of [IrH{␬2(C,O)-CH=CHC(Me)=O}-
(PPh3)2]ClO4 (15)
A solution of 16, generated in situ from 3 (100 mg,
0.12 mmol) and AgClO4 (25 mg, 0.12 mmol) in 10 mL of
dichloromethane, was treated with PPh3 (32 mg, 0.12 mmol)
and stirred for 5 min at room temperature in the dark. The
solution was filtered, the filtrate was brought to dryness in
vacuo, and the remaining white, air-stable solid was washed
three times with 5 mL portions of toluene and twice with
5 mL portions of hexane and dried. Yield: 114 mg (82%),
mp 136 °C (dec.). Conductivity (CH3NO2) Λ = 59 cm2 Ω–1 mol–1.
IR (KBr, cm–1): 2215 ν(IrH), 1550 ν(C=O). 1H NMR
(90 MHz, CDCl3) δ: 8.43 (ddt, 1H, J(HH) = 7.3, J(PeqH) =
7.3, J(PaxH) = 4.2 Hz, IrCH), 7.39–6.82 (m, 30H, PC6H5),
6.66 (d, 1H, J(HH) = 7.3 Hz, IrCH=CH), 2.25 (m, 2H,
CH2CH3), 1.11 (t, 3H, J(HH) = 7.1 Hz, CH2CH3), –21.47
(td, 1H, J(PaxH) = 18.1, J(PeqH) = 10.3 Hz, IrH). 31P NMR
(36.2 MHz, CDCl3) δ: 2.5 (d, J(PP) = 17.6 Hz, dd in off-
resonance, ax-PPh3), –3.1 (d, J(PP) = 17.6 Hz, dt in off-
resonance, eq-PPh3). Anal. calcd. for C59H53ClIrO5P3: C
60.95, H 4.59; found: C 60.34, H 4.25.
A solution of 2 (140 mg, 0.17 mmol) in 15 mL of di-
chloromethane was treated with AgClO4 (35 mg,
0.17 mmol) and stirred for 15 min at room temperature in
the dark. The solution was filtered and the residue was washed
twice with 1 mL portions of CH2Cl2. The filtrate was
brought to dryness in vacuo, the remaining brown-yellow
solid was washed three times with 5 mL portions of hexane
and dried. Yield: 130 mg (86%), mp 131 °C (dec.). Conduc-
tivity (CH3NO2) Λ = 36 cm2 Ω–1 mol–1. IR (KBr, cm–1):
1
2180 ν(IrH), 1550 ν(C=O). H NMR (90 MHz, CDCl3) δ:
9.72 (d, 1H, J(HH) = 7.4 Hz, IrCH), 7.56–7.12 (m, 30H,
PC6H5), 5.96 (d, 1H, J(HH) = 7.4 Hz, IrCH=CH), 1.43 (s,
3H, C(CH3)=O), –21.14 (t, 1H, J(PH) = 15.3 Hz, IrH); data
for isomers 15a and 15b (see Scheme 3): δ: 9.59 (d, J(HH) =
7.4 Hz, IrCH), 6.22 (d, J(HH) = 7.4 Hz, IrCH=CH), 1.48 (s,
C(CH3)=O), –21.90 (br t, J(PH) ~ 15 Hz, IrH). 31P NMR
(36.2 MHz, CDCl3) δ: 23.1 (s, d in off-resonance; at –80 °C
in CD2Cl2 two doublets in off-resonance with δ 22.1 and
21.4). Anal. calcd. for C40H36ClIrO5P2: C 55.17, H 4.41;
found: C 55.24, H 4.32.
Preparation of [IrH(C2H4){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2]ClO4 (19)
A solution of 16, generated in situ from 3 (100 mg,
0.12 mmol) and AgClO4 (25 mg, 0.12 mmol) in 10 mL of
CDCl3, was stirred for 15 min at room temperature in the
dark. The solution was filtered and a slow stream of ethene
was passed through the filtrate for 5 min. The solution was
concentrated to ca. 1 mL in vacuo and the product, which is
only stable in an ethene atmosphere, characterized by NMR
Preparation of [IrH{␬2(C,O)-CH=CHC(Et)=O}(PPh3)2]-
ClO4 (16)
The procedure was analogous to that described for 15, using
3 (140 mg, 0.17 mmol) and AgClO4 (35 mg, 0.17 mmol) as
starting materials. An orange, moderately air-sensitive solid
was obtained. Yield: 133 mg (87%), mp 128 °C (dec.). Con-
ductivity (CH3NO2) Λ = 50 cm2 Ω–1 mol–1. IR (KBr, cm–1):
2185 ν(IrH), 1545 ν(C=O). 1H NMR (90 MHz, CDCl3) δ: 9.74
(d, 1H, J(HH) = 6.9 Hz, IrCH), 7.44–7.12 (m, 30H, PC6H5),
6.04 (d, 1H, J(HH) = 6.9 Hz, IrCH=CH), 1.75 (q, 2H, J(HH) =
7.4 Hz, CH2CH3), 0.64 (t, 3H, J(HH) = 7.4 Hz, CH2CH3),
–21.10 (t, 1H, J(PH) = 15.6 Hz, IrH). 31P NMR (36.2 MHz,
CDCl3) δ: 22.5 (s, d in off-resonance). Anal. calcd. for
C41H38ClIrO5P2: C 54.70, H 4.25; found: C 54.51, H 4.41.
1
spectroscopy. H NMR (90 MHz, CDCl3) δ: 10.04 (d, 1H,
J(HH) = 8.6 Hz, IrCH), 7.51–7.18 (m, 30H, PC6H5), 6.45
(dt, 1H, J(HH) = 8.6, J(PH) = 2.2 Hz, IrCH=CH), 3.55 (t,
4H, J(PH) = 3.1 Hz, C2H4), 1.97 (qt, 2H, J(HH) = 7.3,
J(PH) = 2.4 Hz, CH2CH3), 0.83 (t, 3H, J(HH) = 7.3 Hz,
CH2CH3), –20.85 (t, 1H, J(PH) = 14.2 Hz, IrH). 31P NMR
(36.2 MHz, CDCl3) δ: 13.9 (s, d in off-resonance).
Preparation of [IrH(CH3CϵCH){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2]ClO4 (20)
A solution of 16, generated in situ from 3 (100 mg,
0.12 mmol) and AgClO4 (25 mg, 0.12 mmol) in 10 mL of
Preparation of [IrH(CO){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2]ClO4 (17)
A solution of 16, generated in situ from 3 (100 mg,
© 2006 NRC Canada

212
Can. J. Chem. Vol. 84, 2006
dichloromethane, was stirred for 15 min at room temperature
in the dark. The solution was filtered and a slow stream of
propyne was passed through the filtrate for 1 min. The sol-
vent was evaporated in vacuo, the residue was dissolved in
4 mL of CH2Cl2–hexane (3:1) and chromatographed on
Al2O3 (neutral, activity grade V, length of column 5 cm).
With CH2Cl2–hexane (3:1) a brown fraction was eluted,
which was concentrated to ca. 2 mL in vacuo. A brown,
slightly air-sensitive solid precipitated, which was washed
three times with 5 mL portions of hexane and dried. Yield:
100 mg (87%), mp 112 °C (dec.). Conductivity (CH3NO2)
Λ = 52 cm2 Ω–1 mol–1. IR (KBr, cm–1): 2185 ν(IrH), 1820
THF was treated with NaSPh (17 mg, 0.13 mmol) and
stirred for 15 h at room temperature. The solvent was evapo-
rated in vacuo, the residue was suspended in 10 mL of tolu-
ene, and the solution was filtered. The filtrate was brought
to dryness in vacuo, the remaining orange, air-stable solid
was washed twice with 10 mL portions of hexane and dried.
Yield: 92 mg (78%), mp 157 °C (dec.). IR (KBr, cm–1): 2180
1
ν(IrH), 1570 ν(C=O). H NMR (90 MHz, CDCl3) δ: 9.68 (d,
1H, J(HH) = 8.0 Hz, IrCH), 7.62–7.21 (m, 30H, PC6H5),
6.78–6.58 (m, 5H, SC6H5), 6.47 (d, 1H, J(HH) = 8.0 Hz,
IrCH=CH), 1.64 (q, 2H, J(HH) = 7.1 Hz, CH2CH3), 0.35 (t,
3H, J(HH) = 7.1 Hz, CH2CH3), –22.53 (t, 1H, J(PH) =
15.4 Hz, IrH). 31P NMR (36.2 MHz, CDCl3) δ: 16.8 (s, d in
off-resonance). Anal. calcd. for C47H43ClIrO5P2S: C 62.03,
H 4.76; found: C 61.83, H 4.55.
1
ν(CϵC), 1540 ν(C=O). H NMR (90 MHz, CDCl3) δ: 9.60
(d, 1H, J(HH) = 7.6 Hz, IrCH), 7.66–7.00 (m, 30H, PC6H5),
6.21 (d, 1H, J(HH) = 7.6 Hz, IrCH=CH), 2.55–0.61 (br m,
9H, CH3CϵCH and C2H5), –22.54 (t, 1H, J(PH) = 16.6 Hz,
IrH). 31P NMR (36.2 MHz, CDCl3) δ: 13.7 (s, d in off-
resonance). Anal. calcd. for C44H42ClIrO5P2: C 56.20, H
4.50; found: C 56.14, H 4.23.
Acknowledgements
We thank the Deutsche Forschungsgemeinschaft (SFB
347) and the Fonds der Chemischen Industrie for financial
support. We also gratefully acknowledge support by Mrs. R.
Schedl and Mr. C.P. Kneis (DTA measurements and elemen-
tal analyses) and BASF AG (Ludwigshafen, Germany, chem-
icals).
Preparation of [IrH(MeCN){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2]ClO4 (21)
A solution of 16, generated in situ from 3 (100 mg,
0.12 mmol) and AgClO4 (25 mg, 0.12 mmol) in 10 mL of
dichloromethane, was added dropwise to a solution of
acetonitrile (19 µL, 0.36 mmol) in 5 mL of dichloromethane.
After the reaction mixture was stirred for 5 min at room
temperature, the solution was filtered. The filtrate was
brought to dryness in vacuo, the remaining white, air-stable
solid was washed three times with 5 mL portions of hexane
and dried. Yield: 101 mg (87%), mp 179 °C (dec.). Conduc-
tivity (CH3NO2) Λ = 61 cm2 Ω–1 mol–1. IR (KBr, cm–1):
References
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1
2175 ν(CN), 1565 ν(C=O). H NMR (90 MHz, CDCl3) δ:
9.77 (d, 1H, J(HH) = 8.3 Hz, IrCH), 7.51–7.23 (m, 30H,
PC6H5), 6.37 (dt, 1H, J(HH) = 8.3, J(PH) = 1.7 Hz,
IrCH=CH), 1.82 (qt, 2H, J(HH) = 7.6, J(PH) = 2.2 Hz,
CH2CH3), 1.69 (t, 3H, J(PH) = 1.0 Hz, CH3CN), 0.69 (t, 3H,
J(HH) = 7.6 Hz, CH2CH3), –21.72 (t, 1H, J(PH) = 14.9 Hz,
IrH). 31P NMR (36.2 MHz, CDCl3) δ: 17.3 (s, d in off-
resonance). Anal. calcd. for C43H41ClIrNO5P2: C 54.86, H
4.39, N 1.49; found: C 54.85, H 4.88, N 1.49.
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Preparation of [IrH(PhCN){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2]ClO4 (22)
The procedure was analogous to that described for 21, us-
ing 16 (100 mg, 0.12 mmol) and benzonitrile (37 µL,
0.36 mmol) as starting materials. A pale yellow, moderately
air-sensitive solid was obtained. Yield: 108 mg (90%), mp
148 °C (dec.). Conductivity (CH3NO2) Λ = 59 cm2 Ω–1 mol–1.
IR (KBr, cm–1): 2200 ν(CN), 1555 ν(C=O). 1H NMR
(90 MHz, CDCl3) δ: 9.75 (d, 1H, J(HH) = 7.3 Hz, IrCH),
7.79–7.15 (m, 35H, C6H5CN and PC6H5), 6.47 (d, 1H,
J(HH) = 7.3 Hz, IrCH=CH), 1.84 (q, 2H, J(HH) = 7.3 Hz,
CH2CH3), 0.65 (t, 3H, J(HH) = 7.3 Hz, CH2CH3), –21.33 (t,
1H, J(PH) = 15.2 Hz, IrH). 31P NMR (36.2 MHz, CDCl3) δ:
17.1 (s, d in off-resonance). Anal. calcd. for C48H43ClIrNO5P2:
C 57.45, H 4.32, N 1.40; found: C 57.68, H 4.60, N 1.44.
15. Reviews: (a) N.M.N. Gowda, S.B. Naikar, and G.K.N. Reddy.
Adv. Inorg. Chem. Radiochem. 28, 255 (1984); (b) W. Beck
and K.H. Sünkel. Chem. Rev. 88, 1405 (1988); (c) S.H.
Strauss. Chem. Rev. 93, 927 (1993).
16. For the isomerization of alkyne iridium(I) to vinylidene
iridium(I) complexes, see: (a) F.J. Garcia Alonso, A. Höhn, J. Wolf,
H. Otto, and H. Werner. Angew. Chem. Int. Ed. Engl. 24, 406
Preparation of [IrH(SPh){␬2(C,O)-CH=CHC(Et)=O}-
(PPh3)2] (23)
A suspension of 21 (120 mg, 0.13 mmol) in 15 mL of
© 2006 NRC Canada

Papenfuhs et al.
(1985); (b) A. Höhn and H. Werner. Angew. Chem. Int. Ed.
213
17. H. Werner, A. Höhn, and M. Dziallas. Angew. Chem. Int. Ed.
Engl. 25, 1090 (1986).
18. H. Möhrle, T. Platzek, R. Wille, and D. Wendisch. Z.
Engl. 25, 737 (1986); (c) A. Höhn and H. Werner. J.
Organomet. Chem. 382, 255 (1990); (d) H. Werner, R.W.
Lass, O. Gevert, and J. Wolf. Organometallics, 16, 4077
(1997).
Naturforsch. B: Chem. Sci. 40b, 524 (1985).
© 2006 NRC Canada