Synthesis and reactivity of homo- and hetero-dimetallic complexes bridged by diphenyl-2-pyridylphosphine and hydrides: Regioselectivity of alkyne insertion into unsaturated M1(μ-PPh2Py)(μ-H) 2M2 moieties

Article abstract of DOI:10.1039/b815890h

New homo- and hetero-dimetallic complexes bridged by diphenyl-2- pyridylphosphine and hydrides [(Cp*Ir)(μ-PPh₂Py)(μ-H) ₂(MCp*)][OTf]_n (3: M = Ir, n = 2; 4: M = Rh, n = 2; 5: M = Ru, n = 1) were synthesized. The reactions o

Full text of DOI:10.1039/b815890h

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
Synthesis and reactivity of homo- and hetero-dimetallic complexes bridged by
diphenyl-2-pyridylphosphine and hydrides: regioselectivity of alkyne insertion
into unsaturated M1(l-PPh2Py)(l-H)2M2 moieties†
Yoshinori Takahashi,a Naoaki Murakami,a Ken-ichi Fujita*a,b and Ryohei Yamaguchi*a
Received 11th September 2008, Accepted 25th November 2008
First published as an Advance Article on the web 30th January 2009
DOI: 10.1039/b815890h
New homo- and hetero-dimetallic complexes bridged by diphenyl-2-pyridylphosphine and hydrides
[(Cp*Ir)(m-PPh2Py)(m-H)2(MCp*)][OTf]n (3: M = Ir, n = 2; 4: M = Rh, n = 2; 5: M = Ru, n = 1) were
synthesized. The reactions of 3 with terminal alkynes gave m-vinyl complexes [(Cp*Ir)(m-PPh2Py)(m-H)-
(m-C(R)=CH2)(IrCp*)][OTf]2 (6: R = H; 7: R = CO2Me; 9: R = Ph) and [(Cp*Ir)(m-PPh2Py)(m-H)-
=
(m-CH CHR)(IrCp*)][OTf]2 (8: R = SiMe3; 10: R = Ph). The reactions of 4 with alkynes gave
[(Cp*Ir)(m-PPh2Py)(m-H)(m-C(R)=CH2)(RhCp*)][OTf]2 (11a: R = H; 12a: R = CO2Me; 13a: R = Ph),
two of which are in equilibrium with [(Cp*Ir)(m-PPh2Py)(m-H)(m-CH2=C(CO2Me))(RhCp*)][OTf]2
(12b) and [(Cp*Ir)(m-PPh2Py)(m-H)(m-CH2=C(Ph))(RhCp*)][OTf]2 (13b) at 50 ◦C, respectively. The
reactions of 5 with alkynes gave [(Cp*Ir)(m-PPh2Py)(m-H)(m-CH2=C(R))(RuCp*)][OTf] (14b: R =
CO2Me; 15b: R = Ph). Plausible pathways for the insertion of alkynes to the metal–hydride bonds and
the interconversion of the m-vinyl complexes are discussed. Structures of the cationic parts of 3, 8, 9,
13b, 14b and 15b have been confirmed by X-ray analysis.
also reported the reactions of
a dmpm and dihydrido-
Introduction
bridged diiridium complex, [(Cp*Ir)2(m-H)2(m-dmpm)]2+ [dmpm =
5
Metal hydrides play important roles in a number of transition
metal-catalyzed reactions such as hydrogenation, hydroformyla-
tion and the Wacker–Ho¨chst process.1 Especially, insertion reac-
tions of unsaturated organic molecules into a metal–hydride bond
are quite important, thus fundamental reactivities of monometal-
lic hydrido complexes towards alkenes, alkynes, carbonyls and
other unsaturated compounds have been extensively studied exper-
imentally and theoretically.2 In recent years, the chemistry of multi-
metallic complexes has been attracting much attention, because
cooperative reactivity and synergistic effects of multi-metal centers
in close proximity can be expected.3,4 As for multi-metallic hydrido
complexes, several coordinatively unsaturated complexes having
bridging hydrides have been synthesized and their reactivity
towards unsaturated organic molecules has been disclosed.4b,5–7
For example, Riera and Ruiz reported the reactions of [Mn2(m-
H)2(CO)6(m-dppm)] [dppm = bis(diphenylphosphino)methane]
bis(dimethylphosphino)methane, Cp* = h -C5Me5], with alkynes
to give m-vinyl complexes [(Cp*Ir)2(m-alkenyl)(m-dmpm)(m-
H)]2+.4b In these reactions, the regioselectivity of the alkyne
insertion to give a- and b-isomers and the isomerization process
of these isomers have been demonstrated (eqn (1)).
(1)
However, most of these studies have been performed using sym-
metrical homo-dimetallic complexes in which two metal centers
are in the same environment. In view of high functionality of multi-
metallic complexes, it should be interesting to study the reactivity
of unsymmetrical homo-dimetallic or hetero-dimetallic complexes
containing the unsaturated M1(m-H)M2 core.8 Additionally, it
is also important to reveal the regioselectivity of the insertions
into M1(m-H)M2 in which two metal centers are in different
environments. Herein, we wish to report our studies on the alkyne
insertion reactions into L1M1(m-H)M2L2, which might afford
multiple isomers of m-vinyl complexes.
=
with terminal alkynes to give [Mn2(m-CR CH2)(m-H)(CO)6(m-
dppm)] (R = H, Ph) complexes via insertion of a carbon–
carbon triple bond into a metal–hydride bond.5b Puddephatt
has reported the reversible insertion of alkynes into [Ru2(m-
H)(m-CO)(CO)4(m-dppm)2]+ to give [Ru2(m-CH CH2)(CO)4(m-
=
dppm)2]+ and [Ru2(m-CH CHPh)(CO)4(m-dppm)2] . We have
+
5f
=
aGraduate School of Human and Environmental Studies, Kyoto University,
Sakyo-ku, Kyoto, 606-8501, Japan. E-mail: yama@kagaku.mbox.media.
kyoto-u.ac.jp; Fax: +81 75 753 6634; Tel: +81 75 753 6840
We have focused on diphenyl-2-pyridylphosphine (PPh2Py)9
as an unsymmetrical bridging ligand, which keeps two metal
centers in close proximity and provides different environments
to two metal centers. In this paper, we report the synthesis of
homo- and hetero-dimetallic complexes of iridium, rhodium and
ruthenium bridged by PPh2Py as well as dihydrides, and their
reactivity towards alkynes. The expected eight types of isomers
[four regioisomers (type I to IV) and two conformers of each] are
bGraduate School of Global Environmental Studies, Kyoto University, Sakyo-
ku, Kyoto, 606-8501, Japan. E-mail: fujitak@kagaku.mbox.media.kyoto-
u.ac.jp; Fax: +81 75 753 6634; Tel: +81 75 753 6827
† CCDC reference numbers 701920 3-BPh4, 701921 8-BPh4, 701922 9-
BPh4·(C3H6O), 707683 13b-BPh4·(C3H6O), 701923 14b·(C3H6O) and
701924 15b. For crystallographic data in CIF or other electronic format
see DOI: 10.1039/b815890h
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2029
©

View Article Online
shown in eqn (2). The regioselectivity of these insertion reactions
and the interconversion of the m-vinyl complexes are discussed
below.
(3)
(4)
(2)
Having the template complex 1 in hand, we next carried out
the synthesis of homo- and hetero-dimetallic complexes by the
reaction with coordinatively unsaturated metal precursors. When
an equimolar amount of [Cp*Ir(MeCN)3][OTf]2 was added to a
solution of 1 in acetone, the colour of the solution quickly turned
to dark brown to give the new homo-dimetallic diiridium complex
3 in 92% yield (eqn (5)). The structure of 3 was elucidated by the
spectroscopic data as well as the X-ray diffraction study of the
1
anion-exchanged complex 3-BPh4. In the H NMR spectrum of
3, two signals due to Cp* ligands were observed non-equivalently
at d 1.92 and 1.77 ppm. The former resonance at d 1.92 ppm
was observed as a doublet coupled to phosphorus (JPH = 2 Hz)
while the latter resonance was observed at d 1.77 ppm as a singlet,
indicating that one of the Cp*Ir moieties bound to phosphorus and
the other bound to nitrogen of the pyridine ring. A characteristic
signal due to the bridging hydrido ligands was observed at d
-14.78 ppm as a doublet coupled to phosphorus with a relatively
small coupling constants (JPH = 15 Hz) compared to the terminal
hydrides of monometallic complex 1 (JPH = 31 Hz). Additionally,
a signal due to the a-proton of the pyridine ring was observed at
d 9.66 ppm, which was shifted to lower field compared to that in 1
(d 8.37ppm) or 2 (d 8.68 ppm). In the 31P NMR, asingletresonance
was observed at d 45.6 ppm. The X-ray diffraction study of
3-BPh4, which was prepared by the anion metathesis using
NaBPh4, was carried out to confirm the structure of the cationic
part of 3. The molecular geometry and atom numbering system are
shown in Fig. 1. It is apparent that two Cp*Ir moieties are bridged
Results and discussion
Synthesis of homo- and hetero-dimetallic complexes bridged by
PPh2Py and hydrides
Although dimetallic complexes bridged by PPh2Py are well
known,9 to the best of our knowledge, there has been no
report on the complexes having hydrides as additional bridging
ligands. We planned to synthesize a series of dimetallic complexes
using Cp*Ir(PPh2Py)(H)2 (1) as a template; i.e. the reaction
of 1 with coodinatively unsaturated transition metal precursors
[M2Ln] would afford the dimetallic complexes Cp*Ir(m-PPh2Py)(m-
H)2M2Ln. The template 1 was prepared as follows. At first, the
treatment of [Cp*IrCl2]2 with PPh2Py (1.1 equiv.) in THF at room
temperature gave the monodentate complex Cp*Ir(PPh2Py)(Cl)2
(2) in good yield (eqn (3)).10 In the 1H NMR of 2, a signal due to
the Cp* ligand was observed at d 1.37 ppm as a doublet coupled to
˚
by PPh2Py. The iridium–iridium distance is 2.7122(2) A, which
is comparable to the isoelectronic complex [(Cp*Ir)2(m-dmpm)(m-
4b
H)2]2+ (2.7236(8) A). Two hydrides are located from the Fourier
˚
phosphorus (JPH = 2 Hz). In the 31P{ H} NMR, a single resonance
difference map, clearly showing that hydrides are also bridging
two iridium centers.
1
was found at d 0.8 ppm, which was at lower field compared
to the uncoordinated PPh2Py (d -3.4 ppm). The spectroscopic
data clearly indicated that the PPh2Py ligand was coordinated
to the iridium center through the phosphorus atom as illustrated.
Complex 2 was converted into the dihydrido complex 1 by reaction
with lithium triethylborohydride (eqn (4)). Complex 1 was isolated
in 77% yield after purification by column chromatography. In the
1H NMR of 1, a signal due to two hydrides was observed at
In addition to the homo-dimetallic complex 3, hetero-dimetallic
complexes 4 and 5 were also synthesized. The treatment of 1
with [Cp*Rh(MeCN)3][OTf]2 gave the hetero-dimetallic iridium–
rhodium complex 4 in 83% isolated yield (eqn (5)). Since the
NMR spectra of 4 showed broad unresolved resonance at room
◦
1
temperature; thus those were measured at -20 C.11 In the H
NMR, a signal due to the bridging hydrides were observed at d
-15.30 ppm as a doublet of doublets coupled to both phosphorus
(JPH = 20 Hz) and rhodium (JRhH = 20 Hz), reflecting its core
structure of P-Ir(m-H)2Rh. A characteristic signal due to the
a-proton in the pyridine ring was observed at d 9.43 ppm similar
d -16.89 ppm as a doublet coupled to the phosphorus (JPH
=
1
31 Hz). In the 31P{ H} NMR, a singlet resonance was observed
at d 21.1 ppm. All NMR data (1H, 13C{ H}, and 31P{ H}) were
1
1
consistent with the proposed structure.
2030 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
14 Hz) indicates the syn conformation around the Ir–Cb bond.14
1
In the 13C{ H} NMR, two signals due to the m-vinyl carbons were
observed at d 119.5 (Ca) and 54.2 ppm (Cb). All the NMR data of 6
are consistent with the proposed structure and analogous to those
1
2
=
of the m-vinyl complex [(Cp*Ir)2(m-dmpm)(m2,h ,h -CH CH2)(m-
H)]2+, which we have previously reported.4b Next, the reaction
of 3 with methyl propiolate gave a similar m-vinyl complex 7 in
69% yield (eqn (6)). The structure of 7 can be described as the
a-isomer of the type I (see, eqn (2)). Complex 7 was characterized
1
by NMR spectroscopy. In the H NMR, two signals due to the
m-vinyl protons were observed at d 4.84 (trans b-vinyl proton) and
1
2.42 ppm (cis b-vinyl proton). In the 13C{ H} NMR, signals due
to the m-vinyl carbons were observed at d 120.4 (Ca) and 46.2 ppm
(Cb). The signal patterns of the NMR spectra of 7 were closely
similar to those of 6 except for the a-vinyl proton in 6.
Fig. 1 ORTEP drawing of the cationic part of 3-BPh4. Counter anions
and hydrogen atoms except for metal hydrides are omitted for clarity.
(6)
1
to that in 3. In the 31P{ H} NMR, a signal due to phosphorus
was observed at d 26.1 ppm as a singlet, indicating that there is
no bonding interaction between rhodium and phosphorus. The
similar reaction of 1 with [Cp*Ru(MeCN)3][OTf] gave the hetero-
dimetallic iridium–ruthenium complex 5 (eqn (5)), which was
We next examined the reaction of 3 with an alkyne with a bulky
substituent. When 3 was treated with trimethylsilylacetylene at
room temperature for 15 min, the b-isomer of the m-vinyl complex
8 having the type IV¢ structure was obtained in 95% yield with a
small amount of contaminant (< 10%) (eqn (7)).15 The structure
of 8 was elucidated by NMR analysis and X-ray diffraction study
of the anion exchanged complex 8-BPh4. In the 1H NMR of 8, two
doublets due to the m-vinyl protons were observed atd 8.35 (a-vinyl
proton) and 5.29 ppm (b-vinyl proton). Relatively large coupling
constants between these vinyl protons (JHH = 17 Hz) indicated
1
relatively unstable. In the H NMR of 5, a signal due to two
hydrides was observed at d -16.13 ppm as a doublet coupled to the
phosphorus (JPH = 20 Hz), and another characteristic signal due
to the a-proton of the pyridine ring was observed at d 9.87 ppm.
1
In the 31P{ H} NMR, a singlet signal was observed at d 11.5 ppm.
1
1
All NMR data (1H, 13C{ H}, and 31P{ H}) were consistent with
the proposed structure.
1
its trans configuration. In the 13C{ H} NMR, signals due to the
m-vinyl carbons were observed at d 145.9 ppm as a doublet (Ca,
JPC = 4 Hz) and 99.8 ppm as a doublet (Cb, JPC = 4 Hz). The
structure of the cationic part of 8 was further confirmed by X-ray
crystallography of 8-BPh4 (Fig. 2 and Table 2). The iridium–
(5)
˚
iridium distance is 2.8680(6) A, which is comparable to that of
[(Cp*Ir)2(m-dmpm)(m-H)(m-CH CHPh)] .4b Trimethylsilyl group
2+
=
Reactions of homo-dimetallic complex 3 with alkynes12
is directed to outside away from Cp* ligands and occupies the void
space in front of the pyridine ring because of its steric repulsion.
We have previously reported the reactions of alkynes with the
dmpm and dihydrido-bridged symmetrical diiridium complex,
[(Cp*Ir)2(m-H)2(m-dmpm)]2+, which resulted in the formation of
a mixture of a- and b-isomers of m-vinyl complexes.4b Having the
new diiridium complex 3 bridged by PPh2Py and dihydride in
hand, we examined the reactions with terminal alkynes to reveal
the regioselectivity of the insertion.13 The reaction of 3 with ethyne
at room temperature gave the m-vinyl complex 6 quantitatively,
and 6 was isolated in 84% yield (eqn (6)). Complex 6 was the sole
product, and the formation of other isomers was not observed. In
the 1H NMR of 6, three signals due to m-vinyl ligand were observed
at d 7.35, 4.69 and 2.81 ppm (Table 1). These signals could be
assigned as the a-vinyl proton, the trans b-vinyl proton and the cis
b-vinyl proton, respectively. The relatively large vicinal coupling
(7)
The reaction of 3 with phenylacetylene gave a mixture of isomers
of m-vinyl complexes. The ratio of products was determined
by NMR of a crude mixture [9 (34%) and 10 (43%), along
with an unidentified minor product (eqn (8))].16 By column
chromatography, pure 9 and a mixture of 10 and the unidentified
isomer were obtained. The structure of 9 was determined by
constant between the cis b-vinyl proton and phosphorus (3JPH
=
This journal is The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2031
©

View Article Online
Fig. 3 ORTEP drawing of the cationic part of 9-BPh4. Counter anions
and hydrogen atoms are omitted for clarity. In the unit cell, there are two
independent molecules, which are very similar to each other.
Fig. 2 ORTEP drawing of cationic part of 8-BPh4. Counter anions and
hydrogen atoms are omitted for clarity.
1
signal patterns of the m-vinyl protons and carbons of 10 were very
similar to those of TMS analogue 8, supporting its structure of
the type IV¢.
NMR spectroscopy and X-ray diffraction. In the H NMR of
9, characteristic signals due to the m-vinyl protons were observed
at d 4.86 and 2.65 ppm. The signal at d 2.65 ppm was observed as
a doublet of doublets coupled to phosphorus (JPH = 16 Hz) and
to geminal proton (JHH = 3 Hz) at d 4.86 ppm. In the 13C{ H}
1
NMR spectrum, a signal due to the m-vinyl carbon bound to
iridium (Ca) was observed at d 146.6 ppm, and a signal due to
another m-vinyl carbon (Cb) was observed at d 45.6 ppm. The
structure of the cationic part of 9 was confirmed by X-ray analysis
of the anion exchanged complex 9-BPh4 (Fig. 3). It is apparent
that the structure of 9-BPh4 can be described as the type I. The
carbon–carbon double bond (C(38)–C(39)) coordinates to the
iridium center (Ir(1)) bound to phosphorus, and the a-carbon
is s-bonded to the iridium center (Ir(2)) bound to nitrogen. The
phenyl group on the m-vinyl moiety is directed to below the plane
defined by Ir(1)–C(39)–Ir(2). In this geometry, the cis b-vinylic
proton necessarily adopt syn conformation relative to phosphorus
atom, supporting their spin coupling constants observed in NMR
analysis. Complex 10 was characterized by NMR analysis. In
Reactivities of hetero-dimetallic complexes toward alkynes
We next examined the reactions of hetero-dimetallic complex 4
with ethyne, methyl propiolate, and phenylacetylene (eqn (9)).
Products 11a–13a were isolated in good yields, and their structures
were determined by NMR spectroscopy. The reaction of 4 with
ethyne gave 11a selectively, in which the m-vinyl ligand is s-bonded
to the rhodium center and p-coordinated to the iridium center
1
(the type I). In the H NMR of 11a, signals due to the m-vinyl
protons were observed at d 7.47 (a-vinyl proton), 4.28 (trans b-
vinyl proton) and 3.10 ppm (cis b-vinyl proton) similar to those of
1
6. In the 13C{ H} NMR spectrum, a characteristic signal for the a-
carbon of the m-vinyl ligand was observed in relatively lower field
at d 142.3 ppm as a doublet coupled to rhodium (JRhC = 28 Hz),
and a signal for the b-carbon was observed at d 55.7 ppm as a
singlet. The NMR data strongly suggests that the m-vinyl moiety
is s-bonded to the rhodium center. The reaction of 4 with methyl
propiolate and phenylacetylene gave 12a and 13a, respectively (eqn
(9)). These products were also characterized to be a-isomers of the
type I by NMR spectroscopy. In the 1H NMR of 12a, a signal due
to the trans b-vinyl proton was observed at d 4.15 ppm as a broad
singlet and a signal due to the cis b-vinyl proton was observed at
1
the H NMR of 10, two signals due to the m-vinyl protons were
observed as doublets coupled to each other at d 8.19 and 6.09 ppm,
respectively. In the 13C{ H} NMR, signals due to the m-vinyl
1
carbons were observed at d 140.9 (Ca) and 106.5 ppm (Cb). These
d 2.64 ppm as a doublet of doublets coupled to phosphorus (JPH
=
1
15 Hz) and geminal proton (JHH = 2 Hz). In the 13C{ H} spectrum,
signals for the m-vinyl carbons were observed at d 137.9 ppm (Ca)
as a doublet (JRhC = 26 Hz) and at d 46.6 ppm (Cb) as a singlet.
(8)
1
1
Although the signal patterns in H and 13C{ H} NMR of 12a
were similar to those of diiridium analogue 7, the signal for the
a-carbon in 12a shifted to the lower field. In the 1H and 13C{ H}
1
NMR spectra of 13a, the signal patterns for the m-vinyl moiety
were closely similar to those of 9 except for the coupling between
rhodium and Ca.
2032 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
(9)
(10)
Interestingly, 12a and 13a were slowly converted into the other
isomers 12b and 13b, respectively (eqn (10)). Heating a solution
of 12a in acetone at 50 ◦C for 5 h gave an equilibrium mixture of
12a and 12b in a ratio of 1.5. The structure of 12b was determined
to be as illustrated in eqn (10) by NMR analysis. In the 1H NMR
of 12b, two singlets due to the vinylic protons were observed at
d 7.21 and 5.04 ppm, and a pseudo triplet due to the bridging
hydride coupled to both phosphorus and rhodium was observed
Finally, we investigated the reactions of hetero-dimetallic
complex 5 with alkynes (eqn (11)). Because of the thermal
instability of 5, the reactions of 5 with alkynes were carried out
immediately after 5 was generated in situ. The treatment of 1
with [Cp*Ru(NCMe)3][OTf] in acetone gave a green solution of 5,
then methyl propiolate was added, and the mixture was stirred
for 15 min. By this procedure, the complex 14b, which is an
a-isomer of the type III¢ (s-bonded to the iridium center and
p-coordinated to the ruthenium center), was obtained in 64% yield.
The structure of 14b was determined by NMR spectroscopy and
1
at d -17.07 ppm (J = 22 Hz). In the 13C{ H} NMR, the m-vinyl
carbons were observed at d 146.9 (Ca) and 98.7 ppm (Cb). These
signal patterns were different from those of type I isomers (6, 7,
9 and 11a–13a) or type IV¢ isomers (8 and 10). We characterized
this complex as the type III¢ isomer. Similarly, heating a solution
of 13a in acetone resulted in an equilibrium of 13a (the type I)
1
X-ray diffraction study. In the H NMR, two singlets due to the
vinylic protons were observed at d 5.99 and 3.85 ppm. A signal due
to the bridging hydride was observed at d -19.94 ppm coupled to
1
phosphorus (JPH = 28 Hz). In the 13C{ H} NMR, signals due to
1
and 13b (the type III¢) in a ratio of 0.11. In the H NMR of
the m-vinyl carbons were observed at d 115.6 ppm (Ca) as a doublet
and 77.5 ppm (Cb) as a singlet. These signal patterns are relatively
similar to those of the type III¢ isomers such as 12b and 13b. The
structure of 14b was confirmed by X-ray analysis (Fig. 5). The
carbon–carbon double bond coordinates to the ruthenium center
and the a-carbon was s-bonded to the iridium center and the
methoxycarbonyl group on C(39) atom is directed upward from
the plane defined by Ir(1)–C(39)–Ru(1). The reaction of 5 with
phenylacetylene also gave the complex 15b having the type III¢
13b, signals due to m-vinyl protons were observed at d 6.61 and
1
5.01 ppm. In the 13C{ H} NMR, signals due to m-vinyl carbons
were observed at d 171.1 (Ca) and 86.0 ppm (Cb). The structure of
the cationic part of 13b was confirmed by X-ray diffraction study
of the anion exchanged complex 13b-BPh4 (Fig. 4). It is apparent
that the carbon–carbon double bond coordinates to the rhodium
center and the a-carbon was s-bonded to the iridium center. It
should be noted that phenyl group bound to C(39) atom is directed
upward from the plane defined by Ir(1)–C(39)–Rh(1) in contrast
to 9-BPh4, in which phenyl group is directed downward. Thus,
we characterized 13b as the type III¢ isomer. In contrast to these
results, 11a remained unchanged after heating the solution up to
80 ◦C for 12 h.
1
structure in 96% yield. In the H NMR of 15b, signals due to
the m-vinyl protons were observed at d 5.39 and 4.18 ppm. In the
1
13C{ H} NMR, signals due to the m-vinyl carbons were observed
at d 133.9 ppm as a doublet (Ca) and 75.6 ppm as a singlet (Cb).
Fig. 5 ORTEP drawing of cationic part of 14b. Counter anions and
hydrogen atoms are omitted for clarity. In the unit cell, there are two
independent molecules, which are very similar to each other.
Fig. 4 ORTEP drawing of cationic part of 13b-BPh4. Counter anions and
hydrogen atoms are omitted for clarity.
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2033
©

View Article Online
Finally, X-ray diffraction revealed the structure of 15b (Fig. 6). It is
apparent that the m-vinyl ligand is s-bonded to the iridium center
and p-coordinated to the ruthenium center in a similar manner to
the case of 14b.
(11)
Scheme 1 Plausible pathways for the insertion of alkynes to the dimetallic
complexes 3 and 4
products. As illustrated in Scheme 1, the reaction of 4 with alkynes
would start with coordination of alkynes to the iridium center to
afford A in the similar manner to the case of homo-dimetallic
complex 3. Then, hydrometallation would occur to give a m-vinyl
complex of the type I as a kinetic product. To support the insertion
pathway described above, we have carried out the isotope-labelling
experiments. The reaction of 4 with phenylacetylene-d1 (PhCCD)
gave the deuterated product 13a-d1, in which the trans b-vinylic
proton was selectively dueterated (> 99% D).18 This result strongly
suggests that cis hydrorhodation to the carbon–carbon triple bond
coordinated to the iridium center has occurred.
The reaction of the iridium–rhodium complex 4 with pheny-
lacetylene gave the type I complex 13a exclusively, while a similar
reaction with the iridium–iridium complex 3 gave the mixture
of type I (9) and type IV¢ (10) complexes. These results can be
explained as follows. In the case of 3, both of the pathways
in Scheme 1 would be operative because phenylacetylene is
moderately sterically demanding. On the other hand, in the case of
4, phenylacetylene would be selectively coordinated to the iridium
center in the first step to afford A, because of the greater ability
of iridium for p-back bonding compared to that of rhodium.19
Additionally, the hydrorhodation in A would be faster than the
hydroiridation in B.20 Thus, the pathway through A would be
predominant in the reaction of 4 with phenylacetylene.
Fig. 6 ORTEP drawing of cationic part of 15b. Counter anions and
hydrogen atoms except for metal hydride are omitted for clarity.
Considerations on the regioselectivity in alkyne insertions and the
isomerization of the l-vinyl complexes
From the results shown above, we propose the possible pathways
for the insertion of alkynes to the diiridium complex 3 and the
iridium–rhodium complex 4 (Scheme 1). The selective formation
of the type I complexes (6 and 7) in the reaction of 3 with less bulky
alkynes such as ethyne or methyl propiolate indicates that these
reactions would start with coordination of carbon–carbon triple
bond to the iridium center bound to phosphorus to afford A and
the subsequent hydroiridation could lead to the type I products
(Scheme 1, the left line).17 On the other hand, in the reaction
with trimethylsilylacetylene, sterically demanding trimethylsilyl
group could prevent coordination to the iridium center bound
to phosphorus. Instead, trimethylsilylacetylene would coordinate
to the less hindered iridium center having pyridine ligand to afford
B, in which bulky trimethylsilyl group is directed away from the
diiridium center (Scheme 1, the right line). Then, hydroiridation
would occur to give the type IV¢ complex 8.
As shown in eqn (10), 12a/12b and 13a/13b were in equilibrium
at 50 ◦C. Very recently, Ruiz et al. reported the fast dynamic
fluxional process accompanied by the rotational isomerization
The regioselectivity in the reactions of the hetero-dimetallic
complex 4 can be also rationalized as follows. The selective
formation of the type I complexes (12a and 13a) in the reactions of
4 with alkynes and their isomerization to the type III¢ complexes
(12b and 13b) suggest that the type I complexes are the kinetic
1
2
of a m-vinyl moiety in [Mo2Cp2{m,h ,h -C(CO2Me)=CH2}(m-
PCy2)(CO)2].5h The interconversion processes we show here would
be closely analogous to that reported by Ruiz et al. As illustrated
in Scheme 2, 12a or 13a would be converted to a key intermediate
2034 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
the iridium–rhodium complex 4 with alkynes afforded the type
I isomers exclusively as kinetic products. Rhodium-containing
m-vinyl complexes were in equilibrium between the type I and the
type III¢ isomers at 50 ◦C. This isomerization would proceed via the
elimination of the p-coordinated vinyl moiety followed by metal–
carbon bond rotation and the subsequent vinyl flip isomerization.
In the reactions of the iridium–ruthenium complex 5, the type
III¢ isomers were obtained selectively. It should be noted that one
of the metal centers (left iridium in many cases) would provide a
binding site for alkynes and the other metal center could work for
hydrometallation to the carbon–carbon triple bond, suggesting
the cooperative reactivity and the synergistic effect of multi-metal
centers.12
Experimental
General
Scheme 2 Plausible pathways for the isomerization of the m-vinyl
complexes.
All reactions and manipulations were carried out under an
atmosphere of argon by means of standard Schlenk techniques. 1H,
1
1
13C{ H} and 31P{ H} NMR spectra were recorded on JEOL A-500
C (type I¢) through rotational isomerization of the terminal CH2
group from above to below.21 Then, C would be converted to 12b
or 13b via a flip of the m-vinyl ligand (vinyl flip isomerization),
which is a well-known process in dimetallic m-vinyl complexes
(this process is called “windshield wiper movement”).22 Since no
equilibrium was observed in the case of 11a that has the least
hindered substituent (R = H), the elimination of the p-coordinated
vinyl moiety from the left iridium center might induce the above
isomerization process. Thus, the steric repulsion of substituent
(R = CO2Me or Ph) would cause the elimination of the p-
coordinated vinyl moiety in 12a or 13a followed by the rotation
around the metal–carbon bond to give C. Then, the subsequent
vinyl flip isomerization occurs to afford 12b or 13b. Since the
vinyl flip isomerization is generally known to proceed fast, another
possible path through an intermediate D (type III) to 12b or 13b,
in which the vinyl flip isomerization precedes to the rotational
isomerization, could not be ruled out.
1
and EX-270 spectrometers. 31P{ H} NMR were referenced to an
85% H3PO4 external standard. Melting points were determined on
a Yanagimoto micro melting point apparatus. Elemental analyses
were carried out at the Microanalysis Center of Kyoto University.
Materials
Solvents were dried by using standard procedures and dis-
tilled prior to use. [Cp*IrCl2]2,25 [Cp*Ir(NCMe)3][OTf]2,25
[Cp*Rh(NCMe)3][OTf]225 and [Cp*Ru(NCMe)3][OTf]26 were pre-
pared by literature methods. Chromatography was carried out
by using silica-gel (Wako gel C-200) or activated alumina (Wako,
200 mesh). Other reagents were used as obtained from commercial
source.
Preparation of [Cp*Ir(PPh2Py)Cl2] (2). During the course of
the present study, Govindaswamy et al. reported the preparation of
2 by the reaction of [Cp*IrCl2]2 with diphenyl-2-pyridylphosphine
using dichloromethane as a solvent.10 We have also prepared 2
using THF as a solvent. In a two-necked 50 mL flask, [Cp*IrCl2]2
(806 mg, 1.01 mmol) and diphenyl-2-pyridylphosphine (588 mg,
2.22 mmol) were placed. After addition of THF (10 mL), the
colour of the mixture turned to orange within a few minutes.
Vigorous stirring for over 2 h resulted in the precipitation of an
orange powder. The orange powder was filtered and washed with
ether to give the light-yellow powder 2 (1.04 g, 79%). 2: 1H NMR
(500.00 MHz, CDCl3) d/ppm: 8.68 (1H, m, aromatic), 7.90 (4H,
m, aromatic), 7.74 (1H, br, aromatic), 7.55 (1H, m, aromatic),
7.38–7.35 (4H, m, aromatic), 7.19 (1H, m, aromatic), 1.37 (15H,
In the reactions of 5 with alkynes, the type III¢ complexes (14b
and 15b, eqn (11)) was selectively isolated as a single product. We
carefully traced the reaction of 5 with methyl propiolate at -20 ◦C
1
1
by H and 31P{ H} NMR, and detected an unstable species at
the initial stage (after 5 min) of the reaction.23 Thus, it is highly
probable that 14b and 15b would be also formed through the
similar pathways as those for 12b and 13b (i.e. the initial formation
of the type I intermediate and the subsequent isomerization to the
type III¢ product).24
Conclusion
1
d, J = 2 Hz, Cp*). 13C{ H} NMR (125.65 MHz, CDCl3) d/ppm:
We have synthesized new dihydrido-bridged homo- and hetero-
dimetallic complexes using the PPh2Py ligand as an unsym-
metrical bridging ligand. The reactions of the homo-dimetallic
complex 3 with less hindered alkynes resulted in the selective
formation of type I isomers, while much sterically hindered
trimethylsilylacetylene gave the type IV¢ isomer. The reaction of
3 with moderately hindered phenylacetylene gave a mixture of
type I and type IV¢ isomers, supporting that the regioselectivity
would be mainly dependent on the steric repulsion between the
substituents on alkynes and the dimetallic core. The reactions of
157.5 (d, J = 78 Hz, aromatic), 148.4 (d, J = 16 Hz, aromatic),
135.2 (d, J = 9 Hz, aromatic), 135.1 (d, J = 8 Hz, aromatic), 131.8
(d, J = 54 Hz, aromatic), 131.5 (d, J = 22 Hz, aromatic), 130.2
(d, J = 6 Hz, aromatic), 127.5 (d, J = 10 Hz, aromatic), 123.7 (d,
J = 2 Hz, aromatic), 92.9 (d, J = 3 Hz, C5Me5), 8.1 (s, C5Me5).
1
31P{ H} NMR (202.35 MHz, CDCl3) d/ppm: 0.8 (br, s) (literature
-10.6).10
Preparation of [Cp*Ir(PPh2Py)H2] (1). To a suspension of 2
(2.04 g, 3.08 mmol) in THF (30 mL) in a two-necked 100 mL
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2035
©

View Article Online
Table 1 NMR spectral data of m-vinyl ligands on compounds 6–15
Compound
dH/ppm
dC/ppm
dP/ppm
=
=
6 (Type I)
7.35 (1H, ddd, JPH = 2 Hz, JHH = 12 Hz, 8 Hz,
119.5 (s, Ir–CH ), 54.2 (s, C CH2)
19.7 (s)
=
Ir–CH), 4.69 (1H, dd, JHH = 8 Hz, 2 Hz, C CHH),
2.81 (1H, ddd, JPH = 14 Hz, JHH = 12 Hz, 2 Hz,
=
C CHH)
=
=
=
7 (Type I)
4.84 (1H, d, JHH = 3 Hz, C CHH), 2.42 (1H, dd,
120.4 (s, Ir–C(CO2Me) ), 46.2 (s, C CH2)
20.7 (s)
=
JPH = 16 Hz, JHH = 3 Hz, C CHH)
=
8 (Type IV¢)
9 (Type I)
8.35 (1H, d, JHH = 17 Hz, Ir-CH), 5.29 (1H, d,
145.9 (d, JPC = 4 Hz, Ir–CH ), 99.8 (d, JPC = 4 Hz,
30.3 (s)
21.4 (s)
30.0 (s)
16.7 (s)
=
=
JHH = 17 Hz, C CH)
CH CH–)
=
=
=
=
4.86 (1H, d, JHH = 3 Hz, C CHH), 2.65 (1H, dd,
146.6 (s, Ir–C(Ph) ), 45.6 (s, C CH2)
JPH = 16 Hz, JHH = 3 Hz, C CHH)
=
=
10 (Type IV¢)
11a (Type I)
8.19 (1H, JHH = 14 Hz, Ir–CH ), 6.09 (1H, d,
140.9 (d, JPC = 5 Hz, Ir–CH ), 106.5 (d, JPC
=
=
=
JHH = 14 Hz, C CH)
3 Hz, CH CH–)
=
7.47 (1H, m, Rh–CH), 4.28 (1H, dd, JHH = 7 Hz,
142.3 (d, JRhC = 28 Hz, Rh–CH ), 55.7 (s,
=
=
2 Hz, C CHH), 3.10 (1H, ddd, JPH = 13 Hz, JHH
=
CH CH2)
=
12 Hz, 2 Hz, C CHH)
=
=
12a (Type I)
13a (Type I)
4.15 (1H, br, C CHH), 2.64 (1H, dd, JPH = 15 Hz,
137.9 (d, JRhC = 26 Hz, Rh–C(CO2Me) ), 46.6 (s,
15.8 (s)
16.8 (s)
=
=
JHH = 2 Hz, C CHH)
C CH2)
=
=
=
4.15 (1H, d, JHH = 4 Hz, C CHH), 2.74 (1H, dd,
164.7 (d, JRhC = 23 Hz, Rh–C(Ph) ), 45.8 (s,
=
JPH = 16 Hz, JHH = 4 Hz, C CHH)
C CH2)
=
=
=
=
12b (Type III¢)
13b (Type III¢)
14b (Type III¢)
7.21 (1H, s, C CHH), 5.04 (1H, s, C CHH)
146.9 (m, Ir–C(CO2Me) ), 98.7 (s, C CH2)
18.5 (s)
15.3 (s)
12.9 (s)
=
=
=
=
6.61 (1H, s, C CHH), 5.01 (1H, s, C CHH)
171.1 (brs, Ir–C(Ph) ), 86.0 (d, J = 5 Hz, C CH2)
=
=
=
5.99 (1H, s, C CHH), 3.85 (1H, s, C CHH)
115.6 (d, J = 6 Hz, Ir–C(CO2Me) ), 77.5 (s,
=
C CH2)
=
=
=
=
15b (Type III¢)
5.39 (1H, s, C CHH), 4.18 (1H, s, C CHH)
133.9 (d, J = 10 Hz, Ir–C(Ph) ), 75.6 (s, C CH2)
9.4 (s)
Table 2 Selected bond lengths and angles in 3-BPh4, 8-BPh4, 9-BPh4·(C3H6O), 13b-BPh4·(C3H6O), 14b·(C3H6O) and 15b
8-BPh4
(M = Ir(2))
9-BPh4·(C3H6O)
(M = Ir(2))
13b-BPh4·(C3H6O)
(M = Rh(1))
14b·(C3H6O)
(M = Ru(1))
3-BPh4 (M = Ir(2))
15b (M = Ru(1))
˚
Bond lengths/A
Ir(1)–M
Ir(1)–P(1)
M–N(1)
Ir(1)–C(38)
Ir(1)–C(39)
M–C(38)
M–C(39)
C(38)–C(39)
C(39)–C(40)
2.7122(2)
2.2436(12)
2.157(3)
—
—
—
—
—
—
2.8680(6)
2.2645(18)
2.169(6)
2.058(8)
—
2.178(8)
2.373(7)
1.331(11)
—
2.8877(3), 2.9040(3)
2.303 (2), 2.3002(18)
2.125(5), 2.126(6)
2.191(6), 2.192(7)
2.307(5), 2.288(5)
—
2.033(8), 2.020(8)
1.445(10), 1.426(11)
1.486(11), 1.501(11)
2.9001(7)
2.2768(19)
2.180(6)
—
2.042(8)
2.269(8)
2.316(8)
1.410(11)
1.509(12)
2.9318(4), 2.9402(4)
2.2366(13), 2.2384(14)
2.180(4), 2,175(4)
—
2.083(4), 2.083(4)
2.220(5), 2.204(5)
2.181(5), 2.175(5)
1.402(7), 1.397(8)
1.488(7), 1.485(7)
2.9422(3)
2.2484(11)
2.147(3)
—
2.070(4)
2.206(4)
2.213(4)
1.402(7)
1.495(6)
Bond angles/◦
M–Ir(1)–P(1)
Ir(1)–M–N(1)
P(1)–C(21)–N(1)
88.95(3)
91.26(10)
117.5(3)
82.36(4)
88.78(15)
118.9(5)
79.72(4), 78.92(4)
86.52(12), 86.91(13)
116.0(5), 115.4(5)
80.20(4)
87.48(16)
116.2(5)
79.51(3), 79.38(3)
86.74(10), 86.70(10)
114.6(3), 114.7(3)
79.24(3)
87.62(11)
115.2(3)
flask, 1M LiBEt3H in THF solution (9.2 mL, 9.2 mmol) was
added. After stirring for 3 h at room temperature, the resulting
solution was passed through an alumina short column. Following
chromatography (alumina, eluent: toluene) gave 1 as a colourless
solid (1.40 g, 2.36 mmol, 77%). 1: 1H NMR (500.00 MHz, C6D6)
d/ppm: 8.37 (1H, m, aromatic), 8.11 (1H, m, aromatic), 7.95–7.91
(4H, m, aromatic), 7.13–7.10 (4H, m, aromatic), 7.03–6.95 (3H,
m, aromatic), 6.41 (1H, m, aromatic), 1.94 (15H, s, Cp*), -16.89
(decomposition). Anal calcd for C27H31IrNP: C 54.71, H 5.27,
N 2.36. Found: C 54.97, H 5.31, N 2.19.
Preparation of [(Cp*Ir)2(l-H)2(l-PPh2Py)][OTf]2 (3). In a
50 mL two-necked flask,
1 (403 mg, 0.680 mmol) and
[Cp*Ir(NCMe)3][OTf]2 (510 mg, 0.680 mmol) were placed. When
acetone (12 mL) was added, the colour of the reaction mixture
turned into black and the mixture was stirred for 30 min. After
evaporation of volatiles, the residue was extracted with acetone.
After evaporation of acetone, the black powder was washed with
ether and dried in vacuo to give 3 (759 mg, 0.623 mmol, 92%).
1
(2H, d, J = 31 Hz, Ir–H). 13C{ H} NMR (125.65 MHz, C6D6)
d/ppm: 163.7 (d, J = 74 Hz, aromatic), 148.7 (d, J = 13 Hz,
aromatic), 138.13 (d, J = 54 Hz, aromatic), 134.87 (d, J = 9 Hz,
aromatic), 134.7 (d, J = 10 Hz, aromatic), 130.5 (d, J = 27 Hz,
aromatic), 129.2 (d, J = 2 Hz, aromatic), 128.3 (s), 127.4 (d, J =
10 Hz, aromatic), 92.7 (d, J = 3 Hz, C5Me5), 10.8 (s, C5Me5).
1
3: H NMR (500.00 MHz, acetone-d6) d/ppm: 9.66 (1H, d, J =
6 Hz, aromatic), 8.34–8.29 (1H, m, aromatic), 7.99–7.96 (1H, m,
aromatic), 7.66 (10H, m, aromatic), 7.35 (1H, s, aromatic), 1.92
(15H, d, J = 2 Hz, Cp*), 1.77 (15H, s, Cp*), -14.78 (2H, d,
◦
1
31P{ H} NMR (202.35 MHz, C6D6) d/ppm: 21.1 (s). m.p. 143 C
2036 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
1
J = 15 Hz, Ir–H–Ir). 13C{ H} NMR (125.65 MHz, acetone-d6)
aromatic), 7.63 (1H, m, aromatic), 7.46–7.40 (8H, m, aromatic),
7.10–7.06 (3H, m, aromatic), 1.91 (15H, s, Cp*), 1.32 (15H, s, Cp*),
d/ppm: 160.1 (d, J = 9 Hz, aromatic), 158.2 (d, J = 75 Hz,
aromatic), 141.4 (d, J = 5 Hz, aromatic), 135.2 (d, J = 11 Hz,
aromatic), 133.6 (d, J = 2 Hz, aromatic), 131.3 (s, aromatic),
131.0 (d, J = 11 Hz, aromatic), 130.4 (d, J = 11 Hz, aromatic),
129.1 (s, aromatic), 128.5 (d, J = 62 Hz, aromatic), 122.3 (q, J =
324 Hz, CF3), 100.5 (d, J = 3 Hz, C5Me5), 96.37 (s, C5Me5),
1
-16.13 (2H, d, J = 20 Hz, Ir–H–Ru). 13C{ H} NMR (125.65 MHz,
acetone-d6) d/ppm: 157.6 (d, J = 11 Hz, aromatic), 136.4 (d, J =
5 Hz, aromatic), 133.9 (d, J = 11 Hz, aromatic), 133.0 (d, J =
58 Hz, aromatic), 131.4 (d, J = 2 Hz, aromatic), 129.0 (d, J =
11 Hz, aromatic), 128.6 (d, J = 12 Hz, aromatic), 121.5 (q, J =
318 Hz, CF3), 98.2 (s, C5Me5), 96.4 (d, J = 2 Hz, C5Me5), 10.9 (s,
10.96 (s, C5Me5), 10.17 (s, C5Me5). 31P{ H} NMR (202.35 MHz,
1
acetone-d6) d/ppm: 45.6 (s). m.p. 110–112 ◦C. Anal calcd for
C39H46F6Ir2NO6PS2: C 38.45, H 3.81, N 1.15. Found: C 38.29, H
3.83, N 1.38.
1
C5Me5), 10.5 (s, C5Me5). 31P{ H} NMR (202.35 MHz, acetone-d6)
d/ppm: 11.5 (s). m.p. 109–110 ◦C.
Reaction of ethyne with 3. To an acetone solution (4 mL)
of 3 (41.0 mg, 0.0337 mmol) in a 10 mL Schlenk tube, ethyne
(1 atm.) was introduced by gas balloon. Stirring for 15 min at
room temperature, the dark brown solution turned into a light
green solution with a small amount of precipitate. Then the
solvent was removed in vacuo. The residue was extracted with
dichloromethane and washed with hexane to give the orange
powder 6 (35.1 mg, 0.0282 mmol, 84%). 6: 1H NMR (500.00 MHz,
CD3OD) d/ppm: 8.68 (1H, d, J = 6 Hz, aromatic), 8.08 (1H, m,
aromatic), 7.78 (6H, m, aromatic), 7.66 (2H, m, aromatic), 7.60
(1H, m, aromatic), 7.54 (1H, m, aromatic), 7.35 (1H, ddd, J =
Anion metathesis of 3. In a 30 mL two-necked flask, 3
(118 mg, 0.0967 mmol) and methanol (6 mL) were placed, then
sodium tetraphenylborate (19.9 mg, 0.0581 mmol) was added. A
dark brown solid precipitated. The precipitate was washed with
methanol to give 3-BPh4 in 40% yield (60.0 mg, 0.0385 mmol).
Single crystals suitable for X-ray analysis were obtained by slow
diffusion of hexane into an acetone solution of 3-BPh4. 3-BPh4: 1H
NMR (500.00 MHz, acetone-d6) d/ppm: 9.48 (1H, d, J = 6 Hz,
aromatic), 8.18 (1H, m, aromatic), 7.99–7.96 (1H, m, aromatic),
7.67–7.51 (10H, m, aromatic), 7.34–7.31 (16H, m, BPh4), 6.89
(16H, t, J = 7 Hz, BPh4), 6.74 (8H, t, J = 7 Hz, BPh4), 1.82 (15H,
d, J = 2 Hz, Cp*), 1.63 (15H, s, Cp*), -14.79 (2H, d, J = 15 Hz,
=
12 Hz, 8 Hz, 2 Hz, Ir–CH CH2), 7.30 (2H, aromatic), 4.69 (1H,
=
dd, J = 8, 2 Hz, C CHH), 2.81 (1H, ddd, J = 14 Hz, 12 Hz,
1
Ir–H–Ir). 31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm:
=
2 Hz, C CHH), 1.85 (15H, d, J = 2 Hz, Cp*), 1.79 (15H, s, Cp*),
-17.41 (1H, d, J = 31 Hz, Ir–H–Ir). 13C{ H} NMR (125.65 MHz,
1
45.9 (s). m.p. 163–165 ◦C. Anal calcd for C85H86B2Ir2NP: C 65.50,
H 5.56, N 0.90. Found: C 65.69, H 5.62, N 0.89.
acetone-d6) d/ppm: 160.6 (d, J = 85 Hz, aromatic), 160.0 (d, J =
10 Hz, aromatic), 140.4 (d, J = 5 Hz, aromatic), 136.3 (d, J =
11 Hz, aromatic), 134.7 (s, aromatic), 134.3 (s, aromatic), 134.2
(s, aromatic), 134.2 (s, aromatic), 131.4 (d, J = 11 Hz, aromatic),
131.2 (d, J = 10 Hz, aromatic), 130.2 (s, aromatic), 128.0 (d,
J = 55 Hz, aromatic), 127.0 (d, J = 67 Hz, aromatic), 121.8
Preparation of [(Cp*Ir)(l-H)2(l-PPh2Py)(RhCp*)][OTf]2 (4).
In a 50 mL two-necked flask, 1 (166 mg, 0.280 mmol) and
[Cp*Rh(NCMe)3][OTf]2 (185 mg, 0.280 mmol) were placed. When
acetone (6 mL) was added, the colour of the reaction mixture
turned to dark brown and the mixture was stirred for 30 min. After
evaporation of volatiles, the residue was extracted with acetone.
After evaporation of acetone, the black powder was washed with
ether and dried in vacuo to give 4 (262 mg, 0.232 mmol, 83%).
4: 1H NMR (500.00 MHz, CD2Cl2, 253 K) d/ppm: 9.43 (1H, m,
aromatic), 7.99 (1H, m, aromatic), 7.89 (1H, m, aromatic), 7.52
(7H, m, aromatic), 7.23 (4H, m, aromatic), 1.87 (15H, d, J =
2 Hz, Cp*), 1.38 (15H, s, Cp*), -15.30 (2H, t, J = 20 Hz, Ir–H–
=
(d, J = 312 Hz, CF3), 119.5 (s, Ir–CH ), 103.5 (d, J = 2 Hz,
=
C5Me5), 97.5 (s, C5Me5), 54.2 (s, CH CH2), 9.9 (s, C5Me5), 9.3 (s,
C5Me5). 31P{ H} NMR (202.35 MHz, CD3OD) d/ppm: 19.7 (s).
1
m.p. 129 ◦C (decomposition). Anal calcd for C41H48F6Ir2NO6PS2:
C 39.57, H 3.89, N 1.13. Found: C 39.60, H 3.92, N 1.18.
Reaction of methyl propiolate with 3. To an acetone (3 mL)
solution of 3 (160 mg, 0.132 mmol) in a 30 mL two-necked flask,
methyl propiolate (34.3 mg, 0.48 mmol) was added. Stirring for
15 min at room temperature, the dark brown solution turned into a
light orange solution. Then the solvent was removed in vacuo and
followed by washing with ether to give the pale orange powder 7
(119 mg, 0.914 mmol, 69%). 7: 1H NMR (500.00 MHz, acetone-
d6) d/ppm: 8.86 (1H, d, J = 5 Hz, aromatic), 8.26–8.20 (1H, m,
aromatic), 8.00–7.95 (1H, m, aromatic), 7.82 (10H, m, aromatic),
1
Rh). 13C{ H} NMR (125.65 MHz, CD2Cl2, 233 K) d/ppm: 158.0
(d, J = 11 Hz, aromatic), 138.8 (s, aromatic), 133.4 (d, J = 3 Hz,
aromatic), 132.3 (s, aromatic), 131.5 (d, J = 10 Hz, aromatic), 130.1
(s, aromatic), 129.2 (d, J = 11 Hz, aromatic), 128.6 (s, aromatic),
126.6 (s, aromatic), 120.5 (q, J = 320 Hz, CF3), 100.5 (d, J = 6 Hz,
1
C5Me5), 96.9 (s, C5Me5), 10.2 (s, C5Me5), 9.7 (s, C5Me5). 31P{ H}
NMR (202.35 MHz, CD2Cl2, 253 K) d/ppm: 26.1 (s). m.p. 90–
92 ◦C. Anal calcd for C39H46F6IrNO6PRhS2: C 41.49, H 4.11,
N 1.24. Found: C 41.04, H 4.08, N 1.39.
=
7.69 (1H, s, aromatic), 4.84 (d, 1H, J = 3 Hz, C CHH), 3.87
=
(3H, s, Me), 2.42 (1H, dd, J = 16 Hz, 3 Hz, C CHH), 1.94 (15H,
d, J = 2 Hz, Cp*), 1.87 (15H, s, Cp*), -17.31 (1H, d, J = 31 Hz,
1
Preparation of [(Cp*Ir)(l-H)2(l-PPh2Py)(RuCp*)][OTf] (5).
In a 10 mL Schlenk tube, 1 (26.3 mg, 0.0444 mmol) and
[Cp*Ru(NCMe)3][OTf] (21.8 mg, 0.0428 mmol) were placed.
When acetone (1 mL) was added, the colour of the reaction
mixture turned to green and the mixture was stirred for 30 min.
After the evaporation of volatiles, the residue was extracted with
acetone. After the evaporation of acetone, the green powder was
washed with hexane and dried in vacuo to give 5 as a green
powder (39.2 mg, 0.0401 mmol, 90%). 5: 1H NMR (500.00 MHz,
acetone-d6) d/ppm: 9.87 (1H, d, J = 5 Hz, aromatic), 7.83 (1H, m,
Ir–H–Ir). 13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm: 174.0
=
(s, C O), 159.4 (d, J = 10 Hz, aromatic), 159.0 (d, J = 87 Hz,
aromatic), 140.7 (d, J = 5 Hz, aromatic), 135.6 (d, J = 10 Hz,
aromatic), 135.0 (d, J = 12 Hz, aromatic), 134.7 (d, J = 3 Hz,
aromatic), 134.6 (d, J = 2 Hz, aromatic), 134.4 (d, J = 9 Hz,
aromatic), 131.2 (d, J = 11 Hz, aromatic), 130.9 (d, J = 62 Hz,
aromatic), 130.1 (s), 127.3 (d, J = 54 Hz, aromatic), 126.4 (d,
J = 66 Hz, aromatic), 122.3 (q, J = 320 Hz, CF3), 120.4 (s, Ir–
=
=
CH , 99.0 (s, C5Me5), 52.9 (s, CO2Me), 46.2 (s, C CH2), 9.5 (d,
J = 4 Hz, C5Me5), 8.3 (s, C5Me5). 31P{ H} NMR (202.35 MHz,
1
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2037
©

View Article Online
◦
acetone-d6) d/ppm: 20.7 (s). m.p. 104 C (decomposition). Anal
87, aromatic), 159.6 (d, J = 10 Hz, aromatic), 149.2 (s, aromatic),
=
calcd for C43H50F6Ir2NO8PS2: C 39.65, H 3.87, N 1.08. Found:
146.6 (s, Ir–C(Ph) CH2), 140.5 (d, J = 5 Hz, aromatic), 135.7
C 39.25, H 3.96, N 1.03.
(d, J = 10 Hz, aromatic), 135.3 (d, J = 12 Hz, aromatic), 134.6
(d, J = 3 Hz, aromatic), 134.6 (d, J = 3 Hz, aromatic), 134.5 (d,
J = 10 Hz, aromatic), 132.4 (s, aromatic), 131.3 (d, J = 11 Hz,
aromatic), 130.8 (t, J = 6 Hz, aromatic), 130.3 (s, aromatic), 130.0
(s, aromatic), 128.7 (d, J = 17 Hz, aromatic), 128.4 (s, aromatic),
127.0 (d, J = 65 Hz, aromatic), 122.4 (d, J = 322 Hz, CF3), 104.7
Reaction of trimethylsilylacetylene with 3. To an acetone
(2 mL) solution of 3 (99.5 mg, 0.0817 mmol) in a 10 mL Schlenk
tube, trimethylsilylacetylene (44.5 mg, 0.453 mmol) was added.
Stirring for 15 min at room temperature, the dark brown solution
turned into an orange solution. The solvent was removed in vacuo.
The residue was washed with hexane and extracted with acetone
=
(s, C5Me5), 99.2 (s, C5Me5), 45.6 (s, C CH2), 10.0 (s, C5Me5),
1
9.6 (s, C5Me5). 31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm:
1
to give the orange powder 8 (102 mg, 0.0775 mmol, 95%). 8: H
21.4 (s).
NMR (500.00 MHz, acetone-d6) d/ppm: 8.88 (1H, d, J = 6 Hz,
10 was obtained as a mixture with an unidentified compound.
10: 1H NMR (500.00 MHz, acetone-d6) d/ppm: 8.85 (1H, d, J =
6 Hz, py), 8.37 (1H, t, J = 8 Hz, aromatic), 8.19 (1H, d, J =
=
aromatic), 8.35 (1H, d, J = 17 Hz, Ir–CH C), 8.33–8.31 (1H, m,
aromatic), 7.80–7.60 (10H, m, aromatic), 7.30 (2H, m, aromatic),
=
5.29 (1H, d, J = 17 Hz, CH CH–SiMe3) 1.93 (15H, d, J = 2 Hz,
=
14 Hz, Ir–CH CH), 8.01–7.40 (17H, m, aromatic), 6.09 (1H, d,
Cp*), 1.88 (15H, s, Cp*), 0.28 (9H, s, SiMe3), -17.11 (d, J = 23 Hz,
=
J = 14 Hz, CH CH–Ph), 1.99 (15H, d, J = 2 Hz, Cp*), 1.60
1H, Ir–H–Ir). 13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm:
1
(15H, s, Cp*), -17.21 (1H, d, J = 22 Hz, Ir–H–Ir). 13C{ H} NMR
1
161.0 (d, J = 9 Hz, aromatic), 155.8 (d, J = 71 Hz, aromatic),
(125.65 MHz, acetone-d6) d/ppm: 160.1 (d, J = 8 Hz, aromatic),
156.6 (d, J = 72 Hz, aromatic), 142.1 (d, J = 5 Hz, aromatic), 140.9
=
145.9 (d, J = 4 Hz, Ir–CH ), 142.0 (d, J = 4 Hz, aromatic), 136.1
(d, J = 12 Hz, aromatic), 135.3 (d, J = 10 Hz, aromatic), 134.3
(d, J = 11 Hz, aromatic), 134.0 (d, J = 2 Hz, aromatic), 133.8
(d, J = 11 Hz, aromatic), 133.3 (d, J = 3 Hz, aromatic), 130.8 (d,
J = 11 Hz, aromatic), 130.5 (d, J = 12 Hz, aromatic), 130.3 (d,
J = 31 Hz, aromatic), 129.0 (d, J = 64 Hz, aromatic) 122.4 (q,
J = 322 Hz, CF3), 100.5 (d, J = 2 Hz, C5Me5), 99.8 (d, J = 4 Hz,
=
(d, J = 4 Hz, Ir–CH CH), 138.6–128.4 (aromatic), 106.5 (d, J =
=
3 Hz, CH CH–Ph), 100.1 (d, J = 2 Hz, C5Me5), 98.4 (s, C5Me5),
10.1 (s, C5Me5), 9.2 (s, C5Me5). 31P{ H} NMR (202.35 MHz,
1
acetone-d6) d/ppm: 30.0 (s).
Anion metathesis of 9. 9-BPh4 was obtained by the reaction of
9 (32.9 mg, 0.0253 mmol) with sodium tetraphenylborate (19.9 mg,
0.0581 mmol) in methanol (2 mL). The resulting yellow powder
was washed with methanol to give 9-BPh4 in 78% yield. Single
crystals suitable for X-ray analysis were obtained by slow diffusion
=
CH CHSiMe3), 98.8 (s, C5Me5), 10.8 (s, C5Me5), 10.2 (s, C5Me5),
1.4 (s, SiMe3). 31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm:
1
30.3 (s).
1
Anion metathesis of 8. In a 30 mL two-necked flask, 8 (102 mg,
0.0775 mmol) was placed. After the addition of methanol, NaBPh4
(46.8 mg, 0.137 mmol) was added to the solution. The precipitate
of 8-BPh4 was collected and dried in vacuo. Yield 103.4 mg
(0.0624 mmol, 81%). 8-BPh4: 1H NMR (500.00 MHz, acetone-d6)
d/ppm: 8.75 (d, J = 6 Hz, 1H, aromatic), 8.30 (d, J = 17 Hz, 1H,
of hexane into acetone solution of 9-BPh4. 9-BPh4: H NMR
(500.00 MHz, acetone-d6) d/ppm: 8.85 (1H, d, J = 6 Hz, py),
7.95 (1H, t, J = 9 Hz, py), 7.87–7.77 (5H, m, aromatic), 7.76 (1H,
t, J = 7 Hz, aromatic), 7.63 (2H, m, aromatic), 7.51–7.43 (5H, m,
aromatic), 7.32 (16H, br, BPh4), 7.26–7.15 (3H, m, aromatic), 6.89
(16H, t, J = 7 Hz, BPh4), 6.75 (8H, t, J = 7 Hz, BPh4), 4.74 (1H,
=
Ir–CH C), 7.96 (1H, m, aromatic), 7.71–7.58 (m, 10H, aromatic),
=
=
d, J = 2 Hz, C CHH), 2.57 (1H, dd, J = 16, 2 Hz, C CHH),
7.33 (16H, br, BPh4), 7.23 (m, 2H, aromatic), 6.90 (16H, t, J =
1.61 (15H, d, J = 2 Hz, Cp*), 1.46 (15H, s, Cp*), -17.14 (1H,
d, J = 28 Hz, Ir–H–Ir). 31P{ H} NMR (202.35 MHz, acetone-
1
7 Hz, BPh4), 6.76 (8H, t, J = 7 Hz, BPh4) 5.23 (d, J = 17 Hz,
d6) d/ppm: 21.3 (s). m.p. 195 ◦C (decomposition). Anal calcd for
C93H92B2Ir2NP·C3H6O: C 67.08, H 5.75, N 0.81. Found: C 66.80,
H 5.75, N 0.80.
=
CH CH–SiMe3), 1.86 (d, J = 2 Hz, 15H, Cp*), 1.77 (s, 15H,
Cp*) 0.27 (s, 9H, SiMe3), -17.19 (d, J = 22 Hz, 1H, Ir–H–Ir).
31P{ H} NMR (109.24 MHz, acetone-d6) d/ppm: 29.7 (s). m.p.
1
168 ◦C. Anal calcd for C90H96B2Ir2NPSi: C 65.24, H 5.84, N 0.85.
Found: C 65.12, H 5.69, N 0.89.
Reaction of ethyne with 4. To an acetone solution of 4 (141 mg,
0.220 mmol) in a two-necked flask, ethyne (1 atm.) was introduced
by gas balloon. Stirring for 15 min at room temperature, the
dark brown solution turned into a red solution. The solvent was
removed in vacuo. The residue was column chromatographed on
silica gel (eluent: 10% methanol in dichloromethane) to give 11a
as a red powder (223 mg, 0.192 mmol, 87%). 11a: 1H NMR
(500.00 MHz, acetone-d6) d/ppm: 8.70 (1H, d, J = 6 Hz, py),
8.20 (1H, t, J = 7 Hz, py), 7.91–7.65 (10H, m, aromatic),
Reaction of phenylacetylene with 3. To an acetone solution of
3 (191 mg, 0.157 mmol) in a two-necked flask, phenylacetylene
(81.2 mg, 0.795 mmol) was added. Stirring for 15 min at room
temperature, the dark brown solution turned into a light orange
solution. The solvent was removed in vacuo. Yields of each
isomer were determined by 31P{ H} NMR using an internal
1
standard (9: 34%, 10: 43%). Anal calcd for isomeric mixture of
C47H52F6Ir2NO6PS2: C 42.75, H 3.97, N 1.06. Found: C 42.51, H
4.03, N 1.11. Column chromatography on silica gel (eluent: 5%
methanol in dichloromethane) gave pure 9 in 16% yield (32.9 mg)
as an orange solid. 9: 1H NMR (500.00 MHz, acetone-d6) d/ppm:
9.00 (1H, d, J = 5 Hz, py), 8.27 (1H, t, J = 8 Hz, py), 7.96–
=
7.47 (1H, m, Rh–CH CH2), 7.37 (2H, m, aromatic), 4.28 (1H,
=
dd, J = 7 Hz, 2 Hz, CH CHH), 3.10 (1H, ddd, J = 13 Hz,
=
12 Hz, 2 Hz, CH CHH), 1.93 (15H, d, J = 2 Hz, Cp*),
1.79 (15H, s, Cp*), -17.42 (dd, J = 31 Hz, 20 Hz, Ir–H–Rh).
13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm: 159.2 (d, J =
1
=
7.21 (5H, m, aromatic), 4.86 (1H, d, J = 3 Hz, C CHH), 2.65
88 Hz, aromatic), 158.2 (d, J = 11 Hz, aromatic), 142.3 (d,
J = 28 Hz, Rh–CH), 140.4 (d, J = 5 Hz, aromatic), 135.8 (d,
J = 10 Hz, aromatic), 134.1 (s, aromatic), 134.0 (s, aromatic),
133.8 (d, J = 13 Hz, aromatic), 131.1 (d, J = 11 Hz, aromatic),
=
(1H, dd, J = 16, 3 Hz, C CHH), 1.69 (15H, d, J = 2 Hz,
Cp*), 1.54 (15H, s, Cp*), -17.04 (1H, d, J = 28 Hz, Ir–H–Ir).
13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm: 159.8 (d, J =
1
2038 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
=
130.8 (d, J = 11 Hz, aromatic), 129.3 (s, aromatic), 127.5 (d,
J = 54 Hz, aromatic), 127.2 (d, J = 70 Hz, aromatic), 126.2 (s),
7.98–7.24 (17H, m, aromatic), 4.15 (1H, d, J = 4 Hz, C CHH),
=
2.74 (1H, dd, J = 16 Hz, 4 Hz, C CHH), 1.69 (15H, d, J = 2 Hz,
122.3 (q, J = 323 Hz, CF3), 103.9 (s, C5Me5), 103.0 (s, C5Me5),
Cp*), 1.42 (15H, s, Cp*), -16.66 (1H, dd, J = 29 Hz, 20 Hz,
55.7 (s, CH CH2), 10.2 (s, C5Me5), 9.4 (s, C5Me5). 31P{ H}
Ir–H–Rh). 13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm:
1
1
=
NMR (202.35 MHz, acetone-d6) d/ppm: 16.7 (s). m.p. 70 ◦C
164.7 (d, J = 23 Hz, Rh–C C), 159.1 (d, J = 89 Hz, aromatic),
=
(decomposition).
157.7 (d, J = 11 Hz, aromatic), 148.6 (s, aromatic), 140.5 (d,
J = 6 Hz, aromatic), 135.4 (d, J = 11 Hz, aromatic), 135.2 (d, J =
13 Hz, aromatic), 134.5 (d, J = 2 Hz, aromatic), 134.4 (s, aromatic),
134.3 (s, aromatic), 131.3 (d, J = 11 Hz, aromatic), 130.6 (d, J =
11 Hz, aromatic), 130.0 (s, aromatic), 129.2 (s, aromatic), 128.5 (s,
aromatic), 128.4 (d, J = 59 Hz, aromatic), 127.4 (d, J = 65 Hz,
aromatic), 122.4 (d, J = 325 Hz, CF3), 105.7 (s, C5Me5), 105.1
(d, J = 6 Hz, C5Me5), 45.8 (s, C=CH2), 10.3 (s, C5Me5), 9.6 (s,
Reaction of methyl propiolate with 4. To an acetone (2 mL)
solution of 4 (90.1 mg, 0.0798 mmol) in a two-necked flask, methyl
propiolate (14.6 mg, 0.173 mmol) was added. Stirring for 15 min
at room temperature, the dark brown solution turned into a red
solution. The solvent was removed in vacuo. The residue was
extracted with a minimum volume of acetone, and evaporation
of acetone gave 12a as a red powder (82.4 mg, 0.0679 mmol, 85%).
C5Me5). 31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm: 16.8 (s).
1
1
12a: H NMR (500.00 MHz, acetone-d6) d/ppm: 8.90 (1H, d,
m.p. 87 ◦C (decomposition). Anal calcd for C47H52F6IrNO6PRhS2:
C 45.85, H 4.26, N 1.14. Found: C 45.67, H 4.37, N 1.01.
J = 5 Hz, aromatic), 8.23 (1H, m, aromatic), 7.93–7.70 (9H, m,
aromatic), 7.45 (1H, m, aromatic), 7.29 (m, 2H, aromatic), 4.15
=
(br, 1H, C CHH), 3.87 (3H, s, CO2Me), 2.64 (dd, J = 15 Hz,
Isomerization of 13a. Heating an acetone solution of 13a at
50 ◦C for 5 h resulted in the equilibrium of 13a and 13b (0.1 : 0.9).
The ratio was determined by NMR. 13b: 1H NMR (500.00 MHz,
acetone-d6) d/ppm: 8.77 (1H, d, J = 6 Hz, py), 7.84–7.17 (18H, m,
=
2 Hz, C CHH), 1.95 (15H, d, J = 2 Hz, Cp*), 1.65 (15H, s,
Cp*), -16.95 (dd, J = 29 Hz, 20 Hz, Ir–H–Rh). 13C{ H} NMR
1
(125.65 MHz, acetone-d6) d/ppm: 172.9 (s, CO2Me), 158.1 (d, J =
88 Hz, aromatic), 157.6 (d, J = 12 Hz, aromatic), 140.8 (d, J =
=
=
aromatic), 6.61 (1H, s, C CHH), 5.01 (1H, s, C CHH), 1.91 (15H,
d, J = 2 Hz, Cp*), 1.72 (15H, s, Cp*), -17.64 (1H, t, J = 23 Hz, Ir–
=
12 Hz, aromatic), 137.9 (d, J = 26 Hz, Rh–C(CO2Me) ), 135.4
1
(d, J = 10 Hz, aromatic), 135.0 (d, J = 13 Hz, aromatic), 134.6
(s, aromatic), 134.4 (d, J = 9 Hz, aromatic), 131.3 (d, J = 11 Hz,
aromatic), 130.8 (d, J = 10 Hz, aromatic), 129.4 (s, aromatic),
127.2 (d, J = 51 Hz, aromatic), 127.2 (d, J = 66 Hz, aromatic),
122.3 (q, J = 323 Hz, CF3), 106.6 (s, C5Me5), 104.9 (d, J = 6 Hz,
H–Rh). 13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm: 171.1
=
(brs, Ir–C C), 159.9 (d, J = 12 Hz, aromatic), 156.6 (d, J = 75 Hz,
aromatic), 146.5 (d, J = 3 Hz, aromatic), 139.7 (d, J = 5 Hz,
aromatic), 135.6 (br s, aromatic), 134.0 (d, J = 10 Hz, aromatic),
133.5 (d, J = 2 Hz, aromatic), 133.1 (d, J = 2 Hz, aromatic), 132.2
(d, J = 11 Hz, aromatic), 132.2 (d, J = 65 Hz, aromatic), 130.6
(d, J = 21 Hz, aromatic), 130.1 (d, J = 11 Hz, aromatic), 129.9
(s, aromatic), 129.0 (d, J = 52 Hz, aromatic), 128.9 (s, aromatic),
122.34 (d, J = 322 Hz, CF3), 106.3 (d, J = 7 Hz, C5Me5), 100.5 (s,
=
C5Me5), 52.7 (s, CO2Me), 46.6 (s, C CH2), 9.8 (s, C5Me5), 9.6 (s,
C5Me5). 31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm: 15.8 (s).
1
m.p. 92 ◦C (decomposition).
Isomerization of 12a. Heating an acetone solution of 12a at
50 ◦C for 5 h resulted in the equilibrium of 12a and 12b (0.6 : 0.4).
The ratio was determined by NMR. 12b: 1H NMR (500.00 MHz,
acetone-d6) d/ppm: 8.66 (1H, d, J = 5 Hz, aromatic), 8.27 (1H,
=
C5Me5), 86.0 (d, J = 5 Hz, C CH2), 10.5 (s, C5Me5), 9.7 (s, C5Me5).
1
31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm: 15.3 (s).
Anion metathesis of 13b. 13b-BPh4 was obtained by the
reaction of 1 : 9 mixture of 13a and 13b (123 mg, 0.100 mmol)
with sodium tetraphenylborate (76.0 mg, 0.222 mmol) in methanol
(8 mL). The resulting red powder was washed with methanol to
give 13a-BPh4 and 13b-BPh4 in 87% yield (138 mg. 0.0874 mmol).
Single crystals of 13b-BPh4 suitable for X-ray analysis were
obtained by slow diffusion of hexane into acetone solution of
the mixture of 13a-BPh4 and 13b-BPh4. 13b-BPh4: 1H NMR
(500.00 MHz, acetone-d6) d/ppm: 8.74 (1H, d, J = 5 Hz, py),
7.83–7.37 (16H, m, aromatic), 7.33 (16H, br, BPh4), 7.23 (2H, m,
aromatic), 6.91 (16H, t, J = 7 Hz, BPh4), 6.77 (8H, t, J = 7 Hz,
=
m, aromatic), 7.96–7.69 (m, aromatic), 7.21 (1H, s, C CHH),
=
5.04 (1H, s, C CHH), 3.32 (3H, s, CO2Me), 1.91 (15H, d, J =
2 Hz, Cp*), 1.74 (15H, s, Cp*), -17.07 (1H, t, J = 22 Hz, Ir–
H–Rh). 13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm: 171.5
1
(s, CO2Me), 160.1 (d, J = 10 Hz, aromatic), 158.5 (d, J =
=
72 Hz, aromatic), 146.9 (m, Ir–C(CO2Me) ), 141.0 (d, J = 5 Hz,
aromatic), 135.7 (br, aromatic), 134.7 (d, J = 11 Hz, aromatic),
133.5 (d, J = 41 Hz, aromatic), 132.9 (d, J = 11 Hz, aromatic),
131.7 (d, J = 65 Hz, aromatic), 131.3 (d, J = 11 Hz, aromatic),
130.8 (d, J = 10 Hz, aromatic), 129.9 (d, J = 10 Hz, aromatic),
129.5 (s, aromatic), 129.1 (d, J = 52 Hz), 122.3 (q, J = 323 Hz,
=
=
BPh4), 6.68 (1H, s, C CHH), 5.01 (1H, s, C CHH), 1.92 (15H, d,
J = 2 Hz, Cp*), 1.73 (15H, s, Cp*), -17.58 (t, J = 22 Hz, Ir–H–Rh).
CF3), 107.2 (d, J = 7 Hz, C5Me5), 100.4 (s, C5Me5), 98.7 (s,
C CH2), 53.7 (s, CO2Me), 10.5 (s, C5Me5), 9.9 (s, C5Me5). 31P{ H}
31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm: 15.8 (s).
1
1
=
NMR (202.35 MHz, acetone-d6) d/ppm: 18.5 (s).
Reaction of methyl propiolate with 5. In a 30 mL two-necked
flask, 1 (160 mg, 0.270 mmol) and [Cp*Ru(NCMe)3][OTf] (137 mg,
0.270 mmol) were placed. Acetone (4 mL) was added to the flask,
then the colour of the reaction mixture turned green. After stirring
for 10 min, methyl propiolate (71.7 mg, 0.853 mmol) was added,
and the reaction mixture was stirred for 15 min. After evaporation
of solvent, the residue was chromatographed on silica-gel (eluent:
5% methanol in dichloromethane) to give 14b as a red powder in
Reaction of phenylacetylene with 4. To an acetone solution
(5 mL) of 4 (275 mg, 0.243 mmol) in a two-necked 30 mL flask,
phenylacetylene (115 mg, 1.13 mmol) was added. Stirring for
15 min at room temperature, the dark brown solution turned into
a red solution. After evaporation of the solvent, the residue was
chromatographed on silica-gel with an ice-bath jacket (eluent: 5%
methanol in dichloromethane) to give pure 13a as a red powder
1
1
in 72% isolated yield. 13a: H NMR (500.00 MHz, acetone-d6)
64% yield (183 mg, 0.172 mmol). 14b: H NMR (500.00 MHz,
d/ppm: 8.83 (1H, d, J = 5 Hz, py), 8.22 (1H, t, J = 8 Hz, py),
acetone-d6) d/ppm: 8.30 (1H, d, J = 6 Hz, py), 7.95–7.91 (1H, m,
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2039
©

View Article Online
=
aromatic), 7.70–7.13 (12H, m, aromatic), 5.99 (1H, s, C CHH),
(d, J = 3 Hz, aromatic), 132.1 (d, J = 2 Hz, aromatic), 131.0 (d,
J = 11 Hz, aromatic), 129.9 (d, J = 10 Hz, aromatic), 129.2 (d,
J = 10 Hz, aromatic), 122.5 (q, J = 322 Hz, CF3), 115.6 (d, J =
=
3.85 (1H, s, C CHH), 3.19 (3H, s, CO2Me), 1.75 (15H, d, J =
2 Hz, Cp*), 1.45 (15H, s, Cp*), -19.94 (1H, d, J = 28 Hz, Ir–H–
Ru). 13C{ H} NMR (125.65 MHz, acetone-d6) d/ppm: 174.9 (s,
6 Hz, Ir–C CH2), 97.1 (d, J = 3 Hz, C5Me5), 88.7 (s, C5Me5), 77.5
1
=
=
CO2Me), 161.4 (d, J = 77 Hz, aromatic), 159.5 (d, J = 11 Hz,
aromatic), 137.2 (d, J = 5 Hz, aromatic), 136.1 (d, J = 10 Hz,
aromatic), 135.7 (d, J = 9 Hz, aromatic), 134.7 (s, aromatic), 133.9
(d, J = 65 Hz, aromatic), 132.6 (d, J = 50 Hz, aromatic), 132.4
(s, Ir–C CH2), 52.3 (s, CO2Me), 10.2 (s, C5Me5), 9.8 (s, C5Me5).
1
31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm: 12.9 (s). m.p.
◦
120 C (decomposition). Anal calcd for C45H56F3IrNO6PRuS: C
47.49, H 4.74, N 1.32. Found: C 47.79, H 4.95, N 1.19.
Table 3 Crystal data and structure refinement parameters for 3-BPh4, 8-BPh4, 9-BPh4, 13b-BPh4, 14b and 15b
3-BPh4
8-BPh4
9-BPh4·(C3H6O)
13b-BPh4·(C3H6O)
14b·(C3H6O)
15b
Description of the crystals
Colour, habit
Max. crystal
Red, block
Orange, block
Orange, block
Red, platelet
Orange, block
0.45 ¥ 0.35 ¥ 0.25
Orange, prism
0.33 ¥ 0.25 ¥ 0.15
0.25 ¥ 0.20 ¥ 0.15 0.48 ¥ 0.48 ¥ 0.28 0.30 ¥ 0.20 ¥ 0.10 0.17 ¥ 0.12 ¥ 0.06
dimensions/mm
Crystal system
Space group
Monoclinic
P21/a (#14)
18.8004(4)
18.6689(4)
20.2230(4)
90
92.8600(8)
90
7089.1(3)
4
Orthorhombic
Pbca (#61)
18.3200 (3)
18.9064(3)
45.7263(8)
90
Triclinic
Triclinic
Monoclinic
P21/c (#14)
15.5336(3)
35.6004(6)
15.9795(3)
90
90.9470(7)
90
8835.5(3)
8
Triclinic
¯
¯
¯
P1 (#2)
P1 (#2)
P1 (#2)
˚
a/A
14.2956(3)
23.5089(4)
26.6374(6)
111.4064(8)
103.1060(8)
99.0113(7)
7829.5(3)
4
13.9146(4)
15.6332(4)
18.0394(6)
90.8843(10)
96.7389(10)
90.0164(7)
3896.51(19)
2
11.8483(3)
11.9702(3)
15.2344(3)
85.5897(7)
79.8619(7)
81.6182(8)
2101.28(8)
2
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
V/A
Z
90
90
3
˚
15838.0(5)
8
C90H96B2Ir2NSiP
1656.87
1.390
Formula
FW
C85H86B2Ir2NP
1558.65
1.460
C96H98B2Ir2NPO
1718.87
1.458
C96H98B2IrRhNPO C45H56IrRuNPO6F3S C46H52IrRuNPO3F3S
1629.56
1.389
1120.26
1.684
1080.24
1.707
D
calcd/g cm-3
Data Collection
˚
Radiation, l/A
MoKa, l =
MoKa, l =
MoKa, l =
MoKa, l =
0.71075
173(1)
MoKa, l =
0.71075
173(1)
MoKa, l =
0.71075
173(1)
0.71075
173(1)
0.71075
173(1)
110
0.71075
173(1)
T/K
No. of data images
w Oscillation range/◦
(c = 45.0)
110
440
73
110
44
130.0–190.0
(f = 90.0)
240
130.0–190.0
(f = 30.0)
240
130.0–190.0
(f = 0.0)
300
130.0–190.0
(f = 30.0)
300
130.0–190.0
(f = 120.0)
240
130.0–190.0
(f = 0.0)
240
Exposure rate/s ◦
-1
w Oscillation range/◦
0.0–160.0 (f =
0.0–160.0 (f =
0.0–160.0 (f =
0.0–159.0 (f =
0.0–160.0 (f =
0.0–160.0 (f =
(c = 45.0)
270.0)
180.0)
210.0)
180.0)
270.0)
180.0)
Exposure rate/s ◦
240
240
300
300
240
240
-1
Detector
127.40
127.40
127.40
127.40
127.40
127.40
position/mm
Pixel s◦ize/mm
0.100
54.96
Total: 69 523,
unique: 16 228
(Rint = 0.069)
0.100
54.98
Total: 139 956,
unique: 18 126
(Rint = 0.081)
0.100
54.96
Total: 76 156,
unique: 34 429
(Rint = 0.059)
0.100
54.94
Total: 38 442,
unique: 17 671
(Rint = 0.097)
0.100
54.96
Total: 86 656,
unique: 20 209
(Rint = 0.069)
0.100
54.94
Total: 20 812,
unique: 9541
(Rint = 0.040)
2qmax
/
No. of reflections
measured
Structure determination
No. of observations
10 149 (I >
2.00s(I))
912
9174 (I > 2.00s(I))
10 067 (I > 1.50s(I))
969
21 876 (I >
2.00s(I))
2049
9134 (I > 2.00s(I))
10 358 (I > 1.50s(I))
1025
14 026 (I >
2.00s(I))
1173
9541 (I > 2.00s(I))
7827 (I > 3.00s(I))
569
No. of variables
Reflection/parameter ratio
Absorption correction
Transmission factor
Ra
11.20
10.39
10.76
10.11
12.02
13.76
Multi-scan
0.268–0.563
0.0292
Numerical
0.187–0.381
0.0452
Multi-scan
0.211–0.706
0.0407
Multi-scan
0.547–0.887
0.0516
Multi-scan
0.153–0.416
0.0406
Multi-scan
0.316–0.576
0.0351
a
Rw
0.0404b
1.013
0.0614c
0.0507d
1.010
0.0609e
0.0526f
0.0461g
Goodness of fit
CCDC number
1.080
701921
0.984
707683
1.000
701923
1.012
701924
701920
701922
ꢀ
ꢀ
ꢀ
a R = ꢀFo|–|Fcꢀ/R|Fo|, Rw = [ w(|Fo|–|Fc|)2/ wFo
]
(I > 2.00s(I)). b w = 1/[0.0008Fo + 0.2200s(Fo2)]. c w = 1/[1.0000s(Fo2)]. d w =
2
1/2
2
1/[0.0006Fo + 1.0000s(Fo2)]. e w = 1/[0.0008Fo + 1.0000s(Fo2)]. f w = 1/[0.0003Fo + 1.0000s(Fo2)]. g w = 1/[0.0007Fo + 1.0000s(Fo2)].
2
2
2
2
2040 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
Reaction of phenylacetylene with 5. In a 10 mL Schlenk tube,
1 (62.2 mg, 0.105 mmol) and [Cp*Ru(NCMe)3][OTf] (53.4 mg,
0.105 mmol) were placed. Acetone (4 mL) was added to the flask,
then the colour of reaction mixture turned green. After stirring for
10 min, phenylacetylene (22.6 mg, 0.221 mmol) was added, and
the reaction mixture was stirred for 15 min. After evaporation of
the solvent, the residue was chromatographed on silica-gel (eluent:
5% methanol in dichloromethane) to give 15b as a red powder in
299–327; (b) L. M. Venanzi, Coord. Chem. Rev., 1982, 43, 251; (c) H. D.
Kaesz and R. B. Saillant, Chem. Rev., 1972, 72, 231.
2 Recent examples: (a) E. B. Walczuk, P. C. J. Kamer and P. W. N. M. van
Leeuwen, Angew. Chem., Int. Ed., 2003, 42, 4665; (b) C. A. Sandoval,
T. Ohkuma, K. Mun˜iz and R. Noyori, J. Am. Chem. Soc., 2003, 125,
13490; (c) K. Umezawa-Vizzini and T. R. Lee, Organometallics, 2004,
23, 1448; (d) X. Li, T. Vogel, C. D. Incarvito and R. H. Crabtree,
Organometallics, 2005, 24, 62; (e) H. Wadepohl, U. Kohl, M. Bittner
and H. Ko¨ppel, Organometallics, 2005, 24, 2097; (f) C. S. Weinert, P. E.
Fanwick and I. P. Rothwell, Organometallics, 2005, 24, 5759; (g) A. R.
Sadique, E. A. Gregory, W. W. Brennessel and P. L. Holland, J. Am.
Chem. Soc., 2007, 129, 8112; (h) M. Sparta, K. J. Børve and V. R. Jensen,
J. Am. Chem. Soc., 2007, 129, 8487; (i) A. Comas-Vives, G. Ujaque and
A. Lledo¨s, Organometallics, 2007, 26, 4135; (j) L.-C. Liang, P.-S. Chien
and P.-Y. Lee, Organometallics, 2008, 27, 3082.
3 (a) M. A. Alvarez, M. E. Garc´ıa, V. Riera and M. A. Ruiz, J. Am. Chem.
Soc., 1993, 115., 3786; (b) H. Suzuki, H. Omori, D. H. Lee, Y. Yoshida,
M. Fukushima, M. Tanaka and Y. Moro-oka, Organometallics, 1994,
13, 1129; (c) D. A. Vicic and W. D. Jones, Organometallics, 1999,
18, 134; (d) M. A. Alvarez, M. E. Garc´ıa, V. Riera and M. A. Ruiz,
Organometallics, 1999, 18, 634; (e) J. R. Torkelson, F. H. Antwi-Nsiah,
R. McDonald, M. Cowie, J. G. Pruis, K. J. Jalkanen and R. L. DeKock,
J. Am. Chem. Soc., 1999, 121, 3666; (f) T. Shima and H. Suzuki,
Organometallics, 2000, 19, 2420; (g) D. Ristic-Petrovic, J. R. Tokelson,
R. W. Hilts, R. McDonald and M. Cowie, Organometallics, 2000, 19,
4432; (h) Y. Yuan, M. V. Jime´nez, E. Sola, F. J. Lahoz and L. A. Oro,
J. Am. Chem. Soc., 2002, 124, 752; (i) N. Tsukada, T. Mitsuboshi, H.
Setoguchi and Y. Inoue, J. Am. Chem. Soc., 2003, 125, 12102; (j) K.
Ishiwata, S. Kuwata and T. Ikariya, Organometallics, 2006, 25, 5847;
(k) T. Kawashima, T. Takao and H. Suzuki, J. Am. Chem. Soc., 2007,
129, 11006.
1
96% yield (109 mg, 0.101 mmol). 15b: H NMR (500.00 MHz,
acetone-d6) d/ppm: 8.40 (1H, d, J = 6 Hz, aromatic), 8.03–6.85
=
=
(m, aromatic), 5.39 (1H, s, C CHH), 4.18 (1H, s, C CHH), 1.80
(15H, d, J = 2 Hz, Cp*), 1.50 (15H, s, Cp*), -19.83 (1H, d,
1
J = 27 Hz, Ir–H–Ru). 13C{ H} NMR (125.65 MHz, acetone-
d6) d/ppm: 160.0 (d, J = 11 Hz, aromatic), 158.6 (d, J = 78 Hz,
=
aromatic), 150.5 (s, C C-Cipso), 135.9 (d, J = 5 Hz, aromatic), 134.7
=
(d, J = 10 Hz, aromatic), 133.9 (d, J = 10 Hz, Ir-C(Ph) C), 132.7
(s, aromatic), 132.6 (s, aromatic), 132.6 (s, aromatic), 132.5 (d, J =
5 Hz, aromatic), 132.3 (s, aromatic), 131.9 (s, aromatic), 130.4 (d,
J = 12 Hz, aromatic), 129.9 (d, J = 11 Hz, aromatic), 129.4 (d, J =
10 Hz, aromatic), 128.1 (s, aromatic), 126.6 (s, aromatic), 126.4 (s,
aromatic), 122.5 (q, J = 321 Hz, CF3), 97.4 (d, J = 3 Hz, C5Me5),
=
87.8 (s, C5Me5), 75.6 (s, C CH2), 10.3 (s, C5Me5), 9.7 (s, C5Me5).
31P{ H} NMR (202.35 MHz, acetone-d6) d/ppm: 9.4 (s). m.p.
1
◦
105 C (decomposition). Anal calcd for C46H52F3IrNO3PRuS: C
51.15, H 4.85, N 1.30. Found: C 51.24, H 4.88, N 1.29.
4 (a) K. Fujita, T. Hamada and R. Yamaguchi, J. Chem. Soc., Dalton
Trans., 2000, 1931; (b) K. Fujita, H. Nakaguma, F. Hanasaka and
R. Yamaguchi, Organometallics, 2002, 21, 3749; (c) K. Fujita, H.
Nakaguma, T. Hamada and R. Yamaguchi, J. Am. Chem. Soc.,
2003, 125, 12368; (d) Y. Takahashi, M. Nonogawa, K. Fujita and R.
Yamaguchi, Dalton Trans., 2008, 3546.
X-Ray crystallographic study of 3-BPh4, 8-BPh4, 9-BPh4, 13b-
BPh4, 14b, and 15b. The crystal data and experimental details for
3-BPh4, 8-BPh4, 9-BPh4, 13b-BPh4, 14b, and 15b are summarized
in Table 3. Diffraction data were obtained with a Rigaku RAXIS
RAPID instrument. Reflection data were corrected for Lorentz
and polarization effects. Empirical absorption corrections were
applied for 3-BPh4, 9-BPh4, 13b-BPh4, 14b, and 15b. Numerical
absorption corrections were applied for 8-BPh4. The structures
of 3-BPh4, 8-BPh4, 9-BPh4, 13b-BPh4, and 14b were solved by
the heavy-atom Patterson method27,28 and the structure of and
15b was solved by direct method,28,29 and refined anisotropically
for non-hydrogen atoms by full-matrix least-squares calculations.
Atomic scattering factors and anomalous dispersion terms were
taken from the literature.30 The locations of the metal hydrides
in 3-BPh4 and 15b were determined from Fourier difference map.
The locations of the metal hydrides in 8-BPh4, 9-BPh4, 13b-BPh4,
and 14b could not be determined. Other hydrogen atoms were
located on the idealized positions. In 9-BPh4 and 14b, there were
two independent molecules, which are very similar to each other,
in the unit cell, respectively. The calculations were performed using
the program system CrystalStructure.31,32
5 (a) R. R. Burch, A. J. Shusterman, E. L. Muetterties, R. G. Teller
and J. M. Williams, J. Am. Chem. Soc., 1983, 105, 3546; (b) F. J. G.
Alonso, V. Riera, M. A. Ruiz, A. Tripicchio and M. T. Camellini,
Organometallics, 1992, 11, 370; (c) G. Hogarth and M. H. Lavender,
J. Chem. Soc., Dalton Trans., 1992, 2759; (d) M. K. Anwar, G. Hogarth,
O. S. Senturk, W. Clegg, S. Doherty and M. R. J. Elsegood, J. Chem.
Soc., Dalton Trans., 2001, 341; (e) J. A. Cabeza, I. del Rio, F. Grepioni,
M. Morento, V. Riera and M. Sua´rez, Organometallics, 2001, 20, 4190;
(f) Y. Gao, M. C. Jennings and R. J. Puddephatt, Dalton Trans., 2003,
261; (g) G. Banditelli and A. L. Bandini, Organometallics, 2006, 25,
1578; (h) M. A. Alvarez, M. E. Garc´ıa, A. Ramos, M. A. Ruiz, M.
Lanfranchi and A. Tripicchio, Organometallics, 2007, 26, 5454.
6 Publications on the reactivity of multinuclear complexes without
hydrides towards alkynes: (a) X. L. R. Fontaine, G. B. Jacobson, B. L.
Shaw and M. Thornton-Pett, J. Chem. Soc., Chem. Commun., 1987,
662; (b) J. S. Field, R. J. Haines, J. Sundermeyer and S. F. Woollam,
J. Chem. Soc., Chem. Commun., 1991, 1382; (c) T. Murahashi, T. Otani,
T. Okuno and H. Kurosawa, Angew. Chem., Int. Ed., 2000, 39, 537;
(d) M. Akita, S. Sugimoto, H. Hirakawa, S. Kato, M. Terada, M.
Tanaka and Y. Moro-oka, Organometallics, 2001, 20, 1555; (e) R. Ros,
A. Tassan, R. Roulet, V. Duprez, S. Detti, G. Laurenczy and K. Schlenk,
J. Chem. Soc., Dalton Trans., 2001, 2858; (f) T. Murahashi, T. Okuno,
T. Nagai and H. Kurosawa, Organometallics, 2002, 21, 3679; (g) S.
Tanaka, C. Dubs, A. Inagaki and M. Akita, Organometallics, 2004, 23,
317; (h) S. Takemoto, T. Kobayashi and H. Matsuzaka, J. Am. Chem.
Soc., 2004, 126, 10802; (i) S. Tanaka, C. Dubs, A. Inagaki and M.
Akita, Organometallics, 2005, 24, 163; (j) M. A. Alvarez, Y. Anaya,
M. E. Garc´ıa, M. A. Ruiz and J. Vaissermann, Organometallics, 2005,
24, 2452; (k) G. Higashihara, M. Terada, A. Inagaki and M. Akita,
Organometallics, 2007, 26, 439.
Acknowledgements
We thank Dr Mikio Yamasaki of RIGAKU Corporation for his
advice on the X-ray study of the complex 8-BPh4 (determination
of the lattice parameters and the space group). This work was
partially supported by a grant-in-aid for young scientists (B)
from the Ministry of Education, Culture, Sports, Science and
Technology, Japan.
7 The reactivity of m-vinyl complexes: (a) S. A. R. Knox, Pure Appl.
Chem., 1984, 56, 81; (b) S. A. R. Knox, J. Organomet. Chem., 1990,
400, 255; (c) S. A. R. Knox, J. Cluster Sci., 1992, 3, 385.
8 The insertions of alkynes to mono- or trihydrido-bridged hetero-
dinuclear complexes have been reported: (a) A. D. Hortron, A. C.
Kemball and M. J. Mays, J. Chem. Soc., Dalton Trans., 1988, 2953;
(b) A. J. M. Caffyn, M. J. Ways and P. R. Raithby, J. Chem. Soc.,
Dalton Trans., 1992, 515; (c) T. Shima and H. Suzuki, Organometallics,
Notes and references
1 (a) L. A. Oro and E. Sola, in Recent advances in hydride chemistry,
ed. M. Peruzzini and R. Poli, Elsevier, Amsterdam, 2001, ch. 10, pp.
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 2029–2042 | 2041
©

View Article Online
2000, 19, 2420; (d) R. D. Adams, B. Captain and L. Zhu, J. Am. Chem.
Soc., 2006, 128, 13672; (e) R. D. Adams, B. Captain, E. Trufan and L.
Zhu, J. Am. Chem. Soc., 2007, 129, 7545.
9 Z. Zhang and H. Cheng, Coord. Chem. Rev., 1996, 147, 1, and references
cited therein.
10 During the course of the present study, Govindaswamy et al. reported
the preparation of 2 by the similar reaction: P. Govindaswamy, P. J.
Carroll, Y. A. Mozharivskyj and M. R. Kollipara, J. Chem. Sci., 2006,
118, 319.
11 The complex 4 appears to show dynamic behaviour around room
temperature in solution. This might be due to the metal–metal bond
cleavage process or the migration of the hydrides between the metal
centers, though the detail is not clear.
J. R. Shapley and C. G. Pierpont, Inorg. Chem., 1981, 20, 1528; (c) P. O.
Nubel and T. L. Brown, J. Am. Chem. Soc., 1984, 106, 3474; (d) L. J.
Farrugia, Y. Chi and W.-C. Tu, Organometallics, 1993, 12, 1616.
23 This species rapidly converted into 14b at room temperature. NMR
1
data of the detected species: H NMR d/ppm: 4.90 (dd, JPH = 2 Hz,
JHH = 2 Hz, m-vinyl proton), 0.71 (d, JHH = 2 Hz, m-vinyl proton).
1
13C{ H} NMR d/ppm: 120.7 (d, J = 8 Hz, Ca), 70.9 (d, J = 7 Hz, Cb).
1
31P{ H} NMR d/ppm: 34.9 (s). The structure of this species might be
the type I, I¢, or III. We wish to characterize this species in due course.
24 The isomerization of the type I complexes into the type III¢ complexes
would be ascribed to the differences in bond energies between the
metal–carbon s-bond in the type I and the iridium–carbon s-bond
in the type III¢. Generally, iridium–carbon bonds are most stable, and
rhodium–carbon bonds are more stable than ruthenium–carbon bonds.
Accordingly, the isomerization of 7 did not occur, the isomerization of
12a to 12b slowly proceeded, and the isomerization to 14b would be
very rapid. As to the metal–carbon bond strengths, see: J. A. M. Simo˜es
and J. L. Beauchamp, Chem. Rev., 1990, 90, 629.
12 We have observed that no reaction of the monometallic complex 1 with
alkynes (methyl propiolate and phenylacetylene) occur, indicating that
the dimetallic cores are essential for the alkyne insertion reaction.
13 We have also examined the reactions of 3 with internal alkynes
(diphenylacetylene and dimethyl acetylenedicarboxylate), however, no
reaction takes place.
25 C. White, A. Yates and P. M. Maitlis, Inorg. Synth., 1992, 29, 228.
26 P. J. Fagan, M. D. Ward and J. C. Calabrese, J. Am. Chem. Soc., 1989,
111, 1698.
27 P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, S. Garcia-
Granda, R. O. Gould, J. M. M. Smits and C. Smykalla, The DIRDIF
program system, Technical Report of the Crystallography Laboratory,
University of Nijmegen, Nijmegen, The Netherlands, 1992.
28 P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, R. de
Gelder, R. Israel and J. M. M. Smits, The DIRDIF-99 program
system, Technical Report of the Crystallography LaboratoryUniversity
of Nijmegen, Nijmegen, The Netherlands, 1999.
29 A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, M. Burla,
G. Polidori and M. Camalli, J. Appl. Crystallogr., 1994, 27, 435.
30 (a) D. T. Cromer, and G. T. Waber, International Table for X-
Ray Crystallography, The Kynoch Press, Birmingham, U.K., 1974;
vol. IV, table 2.2 A; (b) J. A. Ibers and W. C. Hamilton, Acta
Crystallogr., 1964, 17, 871; (c) D. C. Creagh, and W. J. McAuley, in
International Tables for X-Ray Crystallography, ed. A. J. C. Wilson,
Kluwer Academic Publishers, Boston, 1992; vol. C, pp. 219–222, table
4.2.6.8; (d) D. C. Creagh, and J. H. Hubbell, in International Tables
for X-Ray Crystallography, ed. A. J. C. Wilson, Kluwer Academic
Publishers, Boston, 1992; vol. C, pp. 200–206, table 4.2.4.3.
14 Similar large vicinal 31P–1H coupling constants in P–O–C–H have been
reported. W. Kung, R. E. Marsh and M. Kainosho, J. Am. Chem. Soc.,
1977, 99, 5471.
15 We could not isolate and characterize the minor product.
16 Heating a solution of pure 9 gave a mixture of 9 and 10, though the
formation of the type I¢, III, or III¢ isomer was not observed.
17 It has been reported that the p-coordination of a carbon–carbon
triple bond to a metal center bound to a phosphorus ligand is
more predominant compared to that to a metal center bound to a
pyridine ligand: C. Dubs, T. Yamamoto, A. Inagaki and M. Akita,
Organometallics, 2006, 25, 1359.
18 We have also carried out the reaction of 3 with phenylacetylene-d1,
which resulted in the formation of 9-d1 having a deuterium at the trans
b-vinyl position (> 90% D).
19 Coordination of an alkyne to iridium center in a hetero-dimetallic
(Ir–Rh) complex has been reported: B. A. Vaartstra and M. Cowie,
Organometallics, 1989, 8, 2388.
20 Theoretical thermochemical analysis of hydrometallation of a carbon–
carbon unsaturated bond by CpIr and CpRh complexes has been
reported: Y. Han, L. Deng and T. Ziegler, J. Am. Chem. Soc., 1997,
119, 5939.
1
2
21 Rotational isomerization of an h ,h -alkenyl ligand on a monometallic
complex has been reported: J. L. Davidson, W. F. Wilson, L. Mano-
jlovic´-Muir and K. W. Muir, J. Organomet. Chem., 1983, 254, C6.
22 (a) J. R. Shapley, S. I. Richter, M. Tachikawa and J. B. Keister,
J. Organomet. Chem., 1975, 94, C43; (b) A. D. Clauss, M. Tachikawa,
31 CrystalStructure3.8, Crystal Structure Analysis Package, Rigaku and
Rigaku/Molecular Structure Corp., 2000–2006.
32 J. R. Carruthers, J. S. Rollett, P. W. Betteridge, D. Kinna, L. Pearce, A.
Larsen and E. Gabe, CRYSTALS Issue 11, Chemical Crystallography
Laboratory, Oxford, 1999.
2042 | Dalton Trans., 2009, 2029–2042
This journal is
The Royal Society of Chemistry 2009
©