Reactions of phosphine ligands with iridium complexes leading to C(sp 3)-H bond activation

Article abstract of DOI:10.1021/om049142i

Treatment of [Ir₂(μ-Cl)₂(coe)₄ (coe = cyclooctene) with the short-bite bifunctional N,P-donor ligand 1-benzyl-2-imidazolyldiphenylphosphine (Ph₂PBnIm) resulted in the oxidative addition of the C(sp³)-H bond from the benzyl group to the metal to give [IrHCl-{Ph₂P(CHPh)Im}(Ph₂PBnIm)] (1), fully characterized by an X-ray study. The related ligand 2-pyridyldiphenylphosphine (Ph₂PPy) reacted with [Ir₂(μ-Cl)₂(coe) ₄] to give the mononuclear iridium(I) complex [IrCl(Ph ₂PPy)₂] (2), which showed P,N-chelating and P-coordinated ligands. Addition of Ph₂BnIm to 2 produced the replacement of the P-coordinated Ph₂PPy ligand along with the benzyl C-H bond addition to indium to give [IrHCl{Ph₂P(CHPh)Im}-(Ph₂PPy)]. This result indicates that mononuclear complexes of the type [IrCl(Ph ₂PBnIm)-(L)] (L = P,N-chelating ligand) are the active species undergoing the C-H bond activation reaction. A related C-H bond activation process of the methylene group of dppm occurs in the reaction of [Ir ₂(μ-Cl)₂(coe)₄] with dppm in toluene to give the hydrido complex with one deprotonated dppm ligand [IrHCl(Ph ₂PCHPPh₂)(dppm)] (4). On the other hand, the hydride migrates to the methanide carbon in 4 on dissolving the complex in CD ₂Cl₂ to establish an equilibrium with [IrCl(dppm) ₂] without H/D exchange. Protonating agents such as HBF ₄·Et₂O and water reacted with complex 4 easily to give [IrHCl(dppm)₂]X (X = BF₄, OH). The mononuclear complex 2 was found to be highly reactive. Reactions of 2 with O₂, H₂, and dichloromethane gave the complexes [IrCl(O ₂)(Ph₂PPy)₂], [IrCl(H)₂(Ph ₂PPy)₂], and [IrCl₂(CH₂Cl)-(Ph ₂PPy)₂], respectively.

Full text of DOI:10.1021/om049142i

Organometallics 2005, 24, 1105-1111
1105
Reactions of Phosphine Ligands with Iridium Complexes
Leading to C(sp3)-H Bond Activation
Cristina Tejel,*,† Miguel A. Ciriano,† Sonia Jime´nez,† Luis A. Oro,†,§
Claudia Graiff,‡ and Antonio Tiripicchio‡
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
CSIC-Universidad de Zaragoza, E-50009 Zaragoza, Spain, Instituto Universitario de Cata´lisis
Homoge´nea, Universidad de Zaragoza, E-50009 Zaragoza, Spain, and Dipartimento di
Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Universita` di Parma,
Parco Area delle Scienze 17/A, I-43100 Parma, Italy
Received November 8, 2004
Treatment of [Ir2(µ-Cl)2(coe)4] (coe ) cyclooctene) with the short-bite bifunctional N,P-
donor ligand 1-benzyl-2-imidazolyldiphenylphosphine (Ph2PBnIm) resulted in the oxidative
addition of the C(sp3)-H bond from the benzyl group to the metal to give [IrHCl-
{Ph2P(CHPh)Im}(Ph2PBnIm)] (1), fully characterized by an X-ray study. The related ligand
2-pyridyldiphenylphosphine (Ph2PPy) reacted with [Ir2(µ-Cl)2(coe)4] to give the mononuclear
iridium(I) complex [IrCl(Ph2PPy)2] (2), which showed P,N-chelating and P-coordinated
ligands. Addition of Ph2PBnIm to 2 produced the replacement of the P-coordinated Ph2PPy
ligand along with the benzyl C-H bond addition to iridium to give [IrHCl{Ph2P(CHPh)Im}-
(Ph2PPy)]. This result indicates that mononuclear complexes of the type [IrCl(Ph2PBnIm)-
(L)] (L ) P,N-chelating ligand) are the active species undergoing the C-H bond activation
reaction. A related C-H bond activation process of the methylene group of dppm occurs in
the reaction of [Ir2(µ-Cl)2(coe)4] with dppm in toluene to give the hydrido complex with one
deprotonated dppm ligand [IrHCl(Ph2PCHPPh2)(dppm)] (4). On the other hand, the hydride
migrates to the methanide carbon in 4 on dissolving the complex in CD2Cl2 to establish an
equilibrium with [IrCl(dppm)2] without H/D exchange. Protonating agents such as HBF4‚Et2O
and water reacted with complex 4 easily to give [IrHCl(dppm)2]X (X ) BF4, OH). The
mononuclear complex 2 was found to be highly reactive. Reactions of 2 with O2, H2, and
dichloromethane gave the complexes [IrCl(O2)(Ph2PPy)2], [IrCl(H)2(Ph2PPy)2], and [IrCl2(CH2Cl)-
(Ph2PPy)2], respectively.
Introduction
neous catalysis, a development of new functionalized
tertiary phosphines able to form metallacycles from
C-H activation reactions could be of importance in this
area. In fact, the very active catalyst for allylic amina-
tion and etherification processes described by Hartwig
resulted to be a cyclometalated phosphoramidite com-
plex.9 In this context, we have been studying the
reactivity of the bifunctional P-C-N ligand (1-benzyl-
2-imidazolyl)diphenylphosphine (Ph2PBnIm). The ligand
was found to be suitable for the construction of homo-
and hetero-dinuclear complexes.1 In the course of these
investigations, we have observed a reversible C(sp2)-H
activation process, which resulted in the formation of
the Ir(I)/Ir(III) compound [IrCl(cod){µ-PPh(C6H4)BnIm}-
IrHCl(cod)].10 Here we report on the C(sp3)-H activation
process of the benzyl group of the Ph2PBnIm ligand by
iridium along with an unusual C-H bond activation of
the methylene group of dppm and related reactions.
Recent work in late transition metal complexes con-
taining bifunctional P-C-N ligands have demonstrated
the utility of such ligands in building homo- and hetero-
dinuclear complexes for which a rich chemistry has been
developed.1-3 C-H bond activation reactions have also
been reported for this type of ligand. As representative
examples, Tani et al. have described that P-N hetero-
chelate hybrid ligands undergo reversible C(sp3)-H
activation reactions.4,5 Andersson et al. have also shown
that related benzylic activations occur within hemilabile
tertiary phosphines (P,O-donor ligands).6-8 Considering
the potential importance of these processes in homoge-
* To whom correspondence should be addressed. E-mail: ctejel@
unizar.es.
† Instituto de Ciencia de Materiales de Arago´n.
§ Instituto Universitario de Cata´lisis Homoge´nea.
‡ Universita` di Parma.
(1) Tejel, C.; Ciriano, M. A.; Bravi, R.; Oro, L. A.; Graiff, C.; Galassi,
R.; Burini, A. Inorg. Chim. Acta 2003, 347, 129, and references therein.
(2) Francio`, G.; Scopelliti, R.; Arena, C. G.; Bruno, G.; Drommi, D.;
Faraone, F. Organometallics 1998, 17, 338.
(3) Zhang, Z.-Z.; Cheng, H. Coord. Chem. Rev. 1996, 147, 1.
(4) Katoaka, Y.; Imanishi, M.; Yamagata, T.; Tani, K. Organo-
metallics 1999, 18, 3563.
(5) Katoaka, Y.; Shizuma, K.; Yamagata, T.; Tani, K. Chem. Lett.
2001, 300.
(6) Sjo¨vall, S.; Andersson, C.; Wendt, O. F. Organometallics 2001,
20, 4919.
(7) Sjo¨vall, S.; Svensson, P. H.; Andersson, C. Organometallics 1999,
18, 5412.
(8) Sjo¨vall, S.; Johansson, M.; Andersson, C. Organometallics 1999,
18, 2198.
(9) Kiener, C. A.; Shu, C.; Incarvito, C.; Hartwig, J. F. J. Am. Chem.
Soc. 2003, 125, 14272.
(10) Tejel, C.; Bravi, R.; Ciriano, M. A.; Oro, L. A.; Bordonaba, M.;
Graiff, C.; Tiripicchio, A.; Burini, A. Organometallics 2000, 19, 3115.
10.1021/om049142i CCC: $30.25 © 2005 American Chemical Society
Publication on Web 02/11/2005

1106 Organometallics, Vol. 24, No. 6, 2005
Tejel et al.
tively. The other ligand Ph2P(CHPh)Im, obtained upon
an oxidative addition of Ph2PBnIm, chelates the metal
center through P1 and C4 atoms, forming a five-
membered chelating ring, in which the Ir1-P1 and Ir1-
C4 bond distances are 2.212(5) and 2.120(15) Å, respec-
tively. As expected the Ir-P bond involving the P atom
in trans position with respect to the carbon atom is
longer than that involving the P atom trans to the
nitrogen atom. The octahedral coordination is completed
by a Cl atom and by a hydride, in the apical positions.
According to the structure found in the solid state,
the 31P{1H} NMR of 1 showed two doublets; that at δ )
-4.1 ppm was assigned to the phosphorus of the
metalated phosphine, labeled Pb in Scheme 1. The other,
shifted at high field (δ ) -25.0 ppm), corresponded to
the phosphorus atom involved in the four-membered
P-C-N-Ir ring (Pa in Scheme 1). The mu-
tually cis-arrangement of both phosphorus atoms was
indicated by the JP-P coupling constant value (12 Hz).
To find the active species leading to 1, the reaction
was monitored by NMR spectroscopy at -40 °C in
CD2Cl2. Two intermediates for this process could be
identified. The major compound detected just after
mixing was the mononuclear species [IrCl(coe)(PPh2-
BnIm)2] (A, Scheme 1), which showed coordinated coe
in the 1H NMR spectrum and two monodentate P-
coordinated Ph2PBnIm ligands, with phosphorus reso-
nances at δ 4.1 and 1.1 ppm (JP-P ) 13 Hz) in the
31P{1H} NMR spectrum. The reaction mixture evolved
to the complex [IrCl(PPh2BnIm)2] (B, Scheme 1) and
free coe in 30 min at low temperature. Complex B
showed P-monodentate and P,N-chelating PPh2BnIm
ligands, as deduced from the two signals at δ -4.0 and
-21.0 ppm (JP-P ) 25 Hz) in the 31P{1H} NMR
spectrum. Finally, complex B transformed cleanly into
1 in 30 min at 25 °C. With this experimental informa-
tion in mind, we hypothesized that the mononuclear
complex [IrCl(PPh2BnIm)2] (B), with a monodentate
phosphine ligand, would be the active species undergo-
ing the C(sp3)-H activation process.
To confirm this hypothesis, we studied the reaction
of [Ir2(µ-Cl)2(coe)4] with the related ligand 2-pyridyl-
diphenylphosphine (Ph2PPy), which lacks the active
benzyl group. The product of this reaction at room
temperature was the mononuclear complex [IrCl(Ph2-
PPy)2] (2), possessing a structure similar to B (Scheme
1), which was isolated as a highly air-sensitive red
microcrystalline solid. The P-monodentate (Pb, Scheme
2) and P,N-chelating (Pa, Scheme 2) coordination modes
of the two Ph2PPy ligands in 2 were evidenced by the
chemical shifts of the signals (δ ) 16.7 (Pb) and -42.9
ppm (Pa)) in the 31P{1H} NMR spectrum, which were
found to be similar to those described for the related
cationic complex [PtCl(Ph2PPy)2]+ characterized crys-
tallographically.11 The cis-arrangement of the phospho-
rus atoms is consistent with the coupling constant JP-P
(23 Hz).
Figure 1. View of the structure of the compound 1
together with the atomic numbering system.
Table 1. Selected Bond Distances (Å) and Angles
(deg) in 1
Ir(1)-Cl(1)
Ir(1)-P(1)
Ir(1)-C(4)
P(1)-C(1)
N(1)-C(1)
N(1)-C(3)
C(2)-C(3)
N(2)-C(2)
N(2)-C(1)
N(1)-C(4)
C(4)-C(5)
2.503(4)
2.212(5)
2.120(15)
1.799(17)
1.35(2)
1.36(2)
1.41(2)
1.35(2)
1.34(2)
1.49(2)
1.49(2)
Ir(1)-H(1)
Ir(1)-P(2)
1.71(12)
2.349(5)
2.176(13)
1.813(18)
1.34(2)
1.40(2)
1.36(2)
1.40(2)
1.39(2)
1.44(2)
1.52(2)
Ir(1)-N(3)
P(2)-C(23)
N(3)-C(23)
N(3)-C(25)
C(24)-C(25)
N(4)-C(24)
N(4)-C(23)
N(4)-C(26)
C(26)-C(27)
C(4)-Ir(1)-N(3) 97.4(6)
N(3)-Ir(1)-P(2) 68.2(4)
C(4)-Ir(1)-Cl(1) 86.4(5)
C(4)-Ir(1)-P(1)
P(1)-Ir(1)-P(2)
N(3)-Ir(1)-Cl(1)
86.7(5)
107.83(17)
86.2(4)
90.45(15)
94(4)
P(1)-Ir(1)-Cl(1) 102.86(16) P(2)-Ir(1)-Cl(1)
C(4)-Ir(1)-H(1) 82(4)
N(3)-Ir(1)-H(1)
P(2)-Ir(1)-H(1)
C(23)-P(2)-Ir(1) 83.0(6)
N(3)-C(23)-P(2) 106.5(13)
C(23)-N(3)-Ir(1) 102.3(11)
P(1)-Ir(1)-H(1)
C(1)-P(1)-Ir(1)
N(1)-C(1)-P(1)
C(1)-N(1)-C(4)
78(4)
101(5)
102.7(6)
115.0(13)
124.1(15)
N(1)-C(4)-Ir(1) 111.5(10)
Results and Discussion
Reaction of [Ir2(µ-Cl)2(coe)4] with 4 molar equiv of
1-benzyl-2-imidazolyldiphenylphosphine (Ph2PBnIm) in
acetone caused the immediate formation of a red solu-
tion, from which a crystalline white material (1),
analyzed as [IrCl(Ph2PBnIm)2], precipitated. Interest-
ingly, this reaction involves a C(sp3)-H bond activation
process under smooth conditions, since 1 displays a
doublet of doublets for a hydride ligand along with a
singlet of intensity 1H for the proton of one benzyl group
bonded to iridium in the 1H NMR spectrum. The
complete characterization of 1 as the mononuclear
complex [IrHCl{Ph2P(CHPh)Im}(Ph2PBnIm)] (1) was
obtained by an X-ray diffraction study. The molecular
structure of 1 is shown in Figure 1 together with the
atomic numbering system. The most important bond
distances and angles are listed in Table 1. The iridium
atom exhibits octahedral coordination as expected for
Ir(III) complexes. One Ph2PBnIm ligand is coordinated
to iridium through P2 and N3 atoms, forming a four-
membered chelating ring in which the Ir1-P2 and Ir-
N3 bond distances are 2.349(5) and 2.176(13) Å, respec-
A further reaction of 2 with Ph2PBnIm caused the
replacement of one of the Ph2PPy ligands along with
the expected C(sp3)-H bond activation of the benzyl
group of the Ph2PBnIm ligand to give [IrHCl{Ph2P-
(CHPh)Im}(Ph2PPy)] (3, Scheme 2), which was isolated
(11) Farr, J. P.; Olmstead, M. M.; Wood, F. E.; Balch, A. L. J. Am.
Chem. Soc. 1983, 105, 792.

Reactions of Phosphine Ligands with Ir Complexes
Organometallics, Vol. 24, No. 6, 2005 1107
Scheme 1
Scheme 2
in moderate yield after recrystallization. Complex 3 was
characterized according to the analytical and spectro-
scopic data. Thus, the hydride ligand was found to be
cis to both phosphorus atoms to give a doublet of
doublets in the 1H NMR spectrum, while the remaining
benzyl proton (Ir-CHPh) gave a doublet (JH-P ) 6.7
(Ph2PBnIm)] (R ) Py, BnIm) with the phosphine
Ph2PBnIm coordinated as monodentate ligand and both
phosphorus in a cis disposition.
Indeed, the C-H activation reaction occurs on
the benzyl group from the monodentate phosphine
Ph2PBnIm, which can be placed in close proximity to
the metal atom. Moreover, the cis disposition of the
benzylic carbon and the hydride ligand found in 1 and
3 is consistent with a concerted oxidative addition
reaction of the C-H bond. Furthermore, the coordina-
tion of the phosphorus from the phosphine Ph2PBnIm
seems to be a prerequisite for the C-H activation
reaction, since an intermolecular C-H activation reac-
tion does not occur on treatment of [IrCl(Ph2PPy)2] (2)
with 1-benzylimidazole. Therefore, the key factor for
these mild C(sp3)-H bond activation reactions seems
to be the preactivation of the benzylic C-H bond by
coordination of the P atom from Ph2PBnIm to the Ir(I)
center, which has been termed “remote activation”.12
Attempts to produce the C-H bond activation reac-
tion by heating the complex [IrCl(Ph2PBnIm)(cod)] at
70 °C in C6D6 failed. This lack of reaction agrees with
the reluctance of related neutral complexes of formula
[IrCl(L)(cod)] (L ) P,O ligand) to undergo C-H oxidative
addition.8 These results indicate that the P-C-N-
chelated ligand in the active species [IrCl(Ph2PR)(Ph2-
PBnIm)] (R ) Py, BnIm) does not have the role of a
simple spectator; on the contrary, it provides to the
1
Hz), which became a singlet in the selective H{31P}
NMR spectrum. The coordination modes and the cis
disposition of the phosphine ligands proposed for 3
(Scheme 2) are consistent with the chemical shifts and
coupling constant of the two signals observed in the
31P{1H} NMR spectrum, at δ -6.4 and -39.9 ppm (JP-P
) 13 Hz). These chemical shifts are similar to those
found for the metalated phosphine Ph2P(CHPh)Im in 1
and the chelating Ph2PPy in 2, respectively.
Although the proposed intermediate in this reaction
(C, Scheme 2) was not observed, the related rhodium
complex [RhCl(dppe)(Ph2PBnIm)] (4) with a monoden-
tate P-coordinated Ph2PBnIm ligand was isolated from
the reaction of [Rh2(µ-Cl)2(dppe)2] with 2 molar equiv
of Ph2PBnIm. The rhodium complex 4, however, did not
undergo C(sp3)-H nor C(sp2)-H activation reactions
even on heating 4 in toluene at reflux for 6 h. In
addition, no C-H activation processes were detected in
the reactions of Ph2PBnIm with the rhodium complexes
[Rh2(µ-Cl)2(coe)4] and [Rh2(µ-Cl)2(C2H4)4], which gave
complicated mixtures without hydride signals in the 1H
NMR spectra of the products.
According to these results, it is reasonable to propose
that the active species that undergo the C(sp3)-H
activation reaction are the complexes [IrCl(Ph2PR)-
(12) Oh, M.; Yu, K.; Li, H.; Watson, E. J.; Carpenter, G. B.; Sweigart,
D. A. Adv. Synth. Catal. 2003, 345, 1053.

1108 Organometallics, Vol. 24, No. 6, 2005
Tejel et al.
Scheme 3
iridium atom the electronic and steric conditions allow-
ing the observed C(sp3)-H activation reactions.
Protonation of complex 5 with HBF4‚Et2O gave the
cationic hydride complex [IrHCl(dppm)2]BF4, which
shows the expected methylene signals for the coordi-
nated dppm ligands and the hydride resonance as a
quintet in the 1H NMR spectrum. However, deprotona-
tion of [IrHCl(dppm)2]BF4 does not occur on treatment
with triethylamine.
As the active complexes [IrCl(Ph2PR)(Ph2PBnIm)] (R
) Py, BnIm) contain a chelating P-C-N ligand not
involved directly in the C-H bond activation, we
speculated if related complexes with ancillary chelating
P-donor ligands could also be suitable for this reaction.
This prompted us to prepare complexes of the type
[Ir2(µ-Cl)2(diphos)2] (diphos ) bis(diphenylphosphino)-
methane (dppm), bis(diphenylphosphino)ethane (dppe))
to be used further in C-H activation reactions. How-
ever, these preparations met with variable success and
led to uncovering an unexpected C-H bond activation
reaction of dppm.
We were most surprised because an apparently
similar reaction of [Ir2(µ-Cl)2(coe)4] with dppm (in a 1:4
molar ratio) in benzene has been reported to give the
Ir(I) complex [IrCl(dppm)2].13 The unique difference
between our procedure and that reported for [IrCl-
(dppm)2] is that dichloromethane was further used to
recrystallize this complex. This prompted us to inves-
tigate the fate of complex 5 in dichloromethane.
Pale yellow crystals of 5 deposited from a concen-
trated and cold solution in dry CH2Cl2 kept under -25
°C. In a separate NMR experiment, a freshly prepared
solution containing initially 5 in dry CD2Cl2 evolved to
a mixture of 5 and [IrCl(dppm)2] in relative proportions
20:80, respectively, in 20 min at room temperature. This
proportion remains unaltered for days, due to a chemical
equilibrium between these species. The interconversion
of the compounds 5 and [IrCl(dppm)2] was confirmed
by the observation of cross-peaks of the methanide and
methylene signals of both compounds in the EXCSY
spectrum. In consequence, the C-H bond activation of
dppm above-described is reversed in dichloromethane
at room temperature to reach an equilibrium of 5 with
[IrCl(dppm)2], in which the reported complex is the
major species.14 This equilibrium could proceed easily
through a square-planar complex easily accessible from
both sides by a migration of the hydride to the meth-
anide carbon in 5 and by the dissociation of one end of
dppm followed by the C-H bond activation of the
methylene group (Scheme 4).
Thus, reaction of [Ir2(µ-Cl)2(coe)4] with 4 molar equiv
of dppm in toluene gave a red solution for a few seconds,
which became pale yellow and rendered a pale yellow
solid (5) in good yield after working up. Indeed, the
reaction requires 2 molar equiv of dppm per iridium;
otherwise mixtures of [Ir2(µ-Cl)2(coe)4] and 5 result if
the phosphine is in defect. The solid was identified as
the hydride complex [IrHCl(Ph2PCHPPh2)(dppm)] (5)
coming from the activation of a methylene proton from
one of the dppm ligands. According to the structure
depicted in Scheme 3, the hydride is cis to the four
phosphorus atoms, since complex 5 exhibits the hydride
resonance as the X part of a AA′BB′X system with
similar couplings to the two phosphorus ligands (JH-P
1
) 10.5, 14.2 Hz) in the H NMR spectrum (Figure 2).
Moreover, the hydride gave a singlet while the meth-
anide proton and carbon from the deprotonated dppm
gave a singlet and a triplet of triplets (JC-P ) 66 and 5
1
Hz) in the H{31P} and 13C{1H} NMR spectra, respec-
tively. The planar disposition of the metal and the four
phosphorus atoms from the diphosphine ligands pro-
duces a AA′BB′ spin system in the 31P{1H} NMR
spectrum of 5 (Figure 2), which is in accordance with
the presence of a symmetry plane that relates two
equivalent halves of the molecule.
Nonetheless, complex 5 is very moisture sensitive and
reacts irreversibly with water to give the complex
[IrHCl(dppm)2]+ as the result of the abstraction of a
proton from water, which may compound the results.
Thus, a mixture of [IrCl(dppm)2], [IrHCl(dppm)2]+, and
5 in relative proportions 40:50:10 resulted on leaving a
solution of 5 in a NMR tube overnight, because of the
adventitious entrance of air into the reaction medium.
As this reaction proceeded, a signal due to hydroxide
at δ 1.842 grew up steadily in the 1H NMR spectrum of
the sample.
As the above-mentioned equilibrium found in di-
chloromethane raises the question of whether the C-H
(13) Hitts, R. H.; Franchuk, R. A.; Cowie, M. Organometallics 1991,
10, 1297.
Figure 2. Signal for the hydride in the 1H NMR spectrum
and 31P{1H} NMR spectrum of complex 5 in CD2Cl2.
(14) We observed a singlet at δ -37.6 ppm in the 31P{1H} NMR
spectrum for [IrCl(dppm)2] instead of the reported value δ -56 ppm.

Reactions of Phosphine Ligands with Ir Complexes
Organometallics, Vol. 24, No. 6, 2005 1109
Scheme 4
Scheme 5
bond activation of dppm depends on the solvent, a
mixture of [Ir2(µ-Cl)2(coe)4] and dppm (in 1:4 molar
ratio) was dissolved in CD2Cl2 in a separate NMR
experiment. The resulting dichroic (green by reflection
and red by transparence) solution showed a main broad
signal in the 31P{1H} NMR spectrum at δ -38 ppm and
the spin system corresponding to complex 5. The broad
signal at room temperature was resolved at -60 °C in
several multiplets, which corresponded to [IrCl(dppm)2]
and two species containing coe, and monodentate and
chelating dppm in equilibrium. Moreover, the coe present
in the mixture produces this equilibrium, since the
methylene protons of coordinated dppm and the olefinic
protons of coordinated coe gave broad signals in the 1H
NMR spectrum at room temperature. The presence of
5 and [IrCl(dppm)2] in the complex mixture resulting
from the reaction of [Ir2(µ-Cl)2(coe)4] with dppm in
dichloromethane evidences that the activation of the
methylene proton of dppm also occurs in dichloro-
methane at room temperature, although the equilibrium
is shifted to [IrCl(dppm)2] in this solvent. In contrast,
the C-H activation reaction to give 5 takes place cleanly
in benzene and toluene, in the NMR tube and in a
preparative scale, in which the product can be easily
purified because it crystallizes out in these solvents.15
It is well known that deprotonation of free and
coordinated dppm occurs by reaction with strong bases
such as BuLi or KOH.16 Deprotonation reactions of
dppm occur also by hydrogen transfer to a coordinated
imido ligand17 and by hydrogen abstraction by a free
radical,18 but the sole precedent of a C-H activation of
dppm in a tris(pyrazolyl)borate iridium complex has
been recently reported by Heinekey.19 A unique example
of methyne C-H activation of the related ligand 2-
pyridylbis(diphenylphosphino)methane by platinum and
iridium complexes has also appeared recently,20 but the
possible mechanisms for these reactions have not been
proposed. The equilibrium between the activated com-
plex 5 and [IrCl(dppm)2] observed in dichloromethane
is evidence of the reversibility of this C-H activation
reaction. Noteworthy, although the 31P{1H} NMR spec-
trum of [IrCl(dppm)2] in the slow-exchange region could
not be observed at low temperature, this compound
should be fluxional not only because it is a pentacoor-
dinated Ir(I) complex but because of the dissociation of
one end of a dppm to give a square-planar species. In
fact, the reactions of this compound with metal frag-
ments to give dinuclear complexes with bridging dppm
described by Cowie evidence the easy dissociation of one
P-donor atom of dppm.13 Moreover, the chemical shift
of the singlet in the 31P{1H} NMR spectrum is between
that of chelating and monodentate dppm. Seen in this
light, we believe the activation of the CH2 group occurs
on the monodentate dppm, which allows the transfer
of the proton of the methylene group to the metal center,
as shown in Scheme 4.
In favor of this proposal, the reaction of [Ir2(µ-Cl)2-
(coe)4] with dppe gave the very stable square-planar
[Ir(dppe)2]+ cation independently of the molar ratio
used, in which the chelating mode of the dppe ligands
prevents any C-H bond activation process. Using a 1:4
molar ratio the previously reported complex [Ir(dppe)2]Cl
was isolated,21 while using a 1:2 molar ratio the ionic
[Ir(dppe)2][IrCl2(coe)2] (6) compound crystallized as an
orange solid. Analytical and spectroscopic data of 6 (see
Experimental Section) agreed with the proposed formula
and ionic nature. A further reaction of PPh2BnIm with
6 led to an equimolar mixture of [Ir(dppe)2]Cl and
complex 1. Moreover, no reaction was observed between
[Ir(dppe)2]Cl and PPh2BnIm even under toluene at
reflux. Therefore, the high stability of the [Ir(dppe)2]+
cation prevented the replacement reaction of even one
dppe ligand by PPh2BnIm.
(15) Complex 5 has been observed to crystallize from a concentrated
mixture of [Ir2(µ-Cl)2(cod)2] and dppm in 1:4 molar ratio in deutero-
benzene. Pe´rez-Torrente, J. J. Personal communication.
(16) Puddephatt, R. J. Chem. Soc. Rev. 1983, 99.
Complex 2 was found to be a very reactive species
(Scheme 5). Thus, the simple air exposure of red
solutions of 2 in acetone caused the formation of a yellow
precipitate corresponding to the dioxygen complex
(17) Ye, C.; Sharp, P. R. Inorg. Chem. 1995, 34, 55, and references
therein.
(18) Torkelson, J. R.; Oke, O.; Muritu, J.; McDonald, R.; Cowie, M.
Organometallics 2000, 19, 854.
(19) Wiley, J. S.; Heinekey, D. M. Inorg. Chem. 2002, 41, 4961.
(20) Mague, J. T.; Krinsky, J. L. Inorg. Chem. 2001, 40, 1962.
(21) Vaska, L.; Catone, D. L. J. Am. Chem. Soc. 1966, 88, 5324.

1110 Organometallics, Vol. 24, No. 6, 2005
Tejel et al.
weights were determined with a Knauer osmometer using
[Ir(O2)Cl(Ph2PPy)2] (7). However, the reaction of 2 with
neat O2 (see Experimental Section) was required to
obtain pure analytical samples of 7, which showed an
IR band ν(O-O) at 844 cm-1. In solution, complex 7 was
found to be fluxional, as indicated by the broad signal
at δ ) -20.0 ppm along with a doublet at δ ) -67.0
ppm in the 31P{1H} NMR spectrum. Scheme 5 shows
one of the possible isomers for this complex.
1
chloroform solutions. H and 31P{1H} NMR spectra were re-
corded on a Bruker ARX 300 and on a Varian UNITY 300 spec-
1
trometer operating at 300.13 and 299.95 MHz for H, respec-
tively. Chemical shifts are reported in parts per million and
referenced to SiMe4 using the residual signal of the deuterated
solvent as reference and 85% phosphoric acid, respectively.
[IrHCl{Ph2P(CHPh)Im}(Ph2PBnIm)] (1). The addition
of solid Ph2PBnIm (137.0 mg, 0.40 mmol) to a solution of [Ir2(µ-
Cl)2(coe)4] (89.6 mg, 0.10 mmol) in acetone (10 mL) caused the
immediate formation of a red solution, which evolved to yellow
in 20 min. After stirring for 3 h, the precipitation of a white
solid took place. The solid was filtered, washed with cold
acetone (2 × 3 mL), and vacuum-dried. Yield: 162 mg (89%).
Anal. Calcd for C44H38N4ClP2Ir: C, 57.92; H, 4.20; N, 6.14.
Solutions of complex 2 reacted with dihydrogen lead-
ing to a mixture of several dihydride complexes from
which the complex [Ir(H)2Cl(Ph2PPy)3] (8) could be
identified as the main product. According to the formu-
lation, complex 8 was obtained in good yield by carrying
out the above-described reaction in the presence of 1
molar equiv of Ph2Ppy. A clean synthesis of 8 consists
in the reaction of [Ir2(µ-Cl)2(cod)2] with dihydrogen in
the presence of 6 molar equiv of Ph2PPy. Complex 8 was
easily identified as the isomer depicted in Scheme 5
from the spectroscopic data (see Experimental Section).
A slow reaction with the solvent was observed on
dissolving complex 2 in dichloromethane. The product
was found to be the compound [IrCl2(η1-CH2Cl)(Ph2-
PPy)2] (9) (Scheme 5), as the result of the oxidative
addition of one C-Cl bond from the dichloromethane
to iridium. The most relevant spectroscopic feature of
9 related to its structure was an AB spin system in the
1H{31P} NMR spectrum corresponding to the dia-
stereotopic protons of the chloromethyl Ir-CH2Cl group,
1
Found: C, 57.06; H, 4.06; N, 6.01. H NMR (25 °C, CD2Cl2):
δ multiplets from 7.66 to 6.52 (34H, Ph), 6.46 (d, JH-P ) 7.2,
1H, Ir-CH), 4.89 (δA, 1H) and 4.82 (δB, JA-B ) 15.0 Hz, 1H)
(PhCH2), -20.42 (dd, JH-P ) 21.9 and 10.4 Hz, 1H, Ir-H).
31P{1H} NMR (25 °C, CD2Cl2): δ -4.1 (d, JP-P ) 12 Hz), -25.0
(d, JP-P ) 12 Hz). MS (FAB+): 912 (65%, M+), 875 (100%, M
- Cl+). MW Calcd for C44H38N4ClP2Ir: 912. Found: 1010.
[IrCl(Ph2PPy)2] (2). The addition of solid Ph2PPy (117.5
mg, 0.45 mmol) to a suspension of [Ir2(µ-Cl)2(coe)4] (100.0 mg,
0.11 mmol) in acetone (5 mL) caused the formation of a red
solution in 10 min. The solution was concentrated to ca. 2 mL,
and the slow addition of hexane (20 mL) gave a red micro-
crystalline solid that was filtered off under argon, washed with
hexane (2 × 5 mL), and vacuum-dried. Yield: 130 mg (77%).
Anal. Calcd for C34H28N2ClP2Ir: C, 54.14; H, 3.74; N, 3.71.
1
Found: C, 53.98; H, 3.76; N, 3.93. H NMR (25 °C, CD2Cl2):
1
which appeared as two doublets of doublets in the H
δ 9.04 (br s, 1H); 8.19 (d, J ) 4 Hz, 1H); multiplets from 7.90
to 6.97 (26H). 31P{1H} NMR (25 °C, CD2Cl2): δ 16.7 (d, JP-P
)
NMR spectrum (JH-P ) 2.3 and 7.4 Hz for the A and B
protons, respectively) due to the coupling with the
phosphorus atom in trans position, labeled Pa in Scheme
5. In addition the presence of terminal and chelated
phosphine ligands was deduced from the distinctive
chemical shifts in the 31P{1H} NMR spectrum.
23 Hz, Pb), -42.9 (d, JP-P ) 23 Hz, Pa). MS (FAB+): 754 (30%,
M+), 719 (100%, M - Cl+).
[IrHCl{Ph2P(CHPh)Im}(Ph2PPy)] (3). Solid Ph2PBnIm
(72.6 mg, 0.21 mmol) was added to a suspension of [IrCl-
(Ph2PPy)2] (2) (160.0 mg, 0.21 mmol) in acetone (5 mL). After
stirring for 4 h an orange precipitate was formed. The
suspension was concentrated to ca. 2 mL, and hexane (10 mL)
was added to complete the precipitation. The solid was filtered,
In conclusion, easy C(sp3)-H bond activation reac-
tions from a “CH2Ph” group can take place under
smooth conditions in mononuclear iridium complexes of
the type [IrCl(L2)(Ph2PBnIm)] (L2 ) Ph2PPy, Ph2-
PBnIm). The key for these activation reactions was
found to be the remote preactivation of the benzyl group
by coordination of the P-end of the substrate to iridium.
The related unusual C-H bond activation of a methyl-
ene group of dppm in [IrCl(dppm)2] occurs probably
through a proton transfer to the metal from a mono-
dentate dppm ligand.
1
washed with hexane, and vacuum-dried. The H NMR of the
crude product (184.0 mg) showed a mixture of the title
compound (60%), complex 1 (20%), and another unidentified
minor species. This crude was recrystallized twice from
dichloromethane/hexane to render orange microcrystals cor-
responding to 3. Yield: 71 mg (40%). Anal. Calcd for C39H33N3-
ClP2Ir: C, 56.21; H, 3.99; N, 5.04. Found: C, 56.32; H, 3.86;
N, 4.93. 1H NMR (25 °C, CDCl3): δ multiplets from 7.84 to
7.04 (30H), 6.88 (s, 1H, Im), 6.35 (d, JH-Pa ) 6.7 Hz, 1H, Ir-
CHPh), -19.40 (dd, JH-Pb ) 15.0 Hz, JH-Pb ) 9.0 Hz, 1H, Ir-
H). 31P{1H} NMR (25 °C, CDCl3): δ -6.4 (d, JP-P ) 13 Hz,
Pb), -39.9 (d, JP-P ) 13 Hz, Pa).
Experimental Section
All the reactions were carried out under argon using
standard Schlenk techniques. [Ir2(µ-Cl)2(coe)4],22 [Ir2(µ-Cl)2-
(cod)2],23 and 1-benzyl-2-imidazolyldiphenylphosphine (PPh2-
BnIm)24 were prepared according to literature methods, while
2-pyridyldiphenylphosphine was purchased from Aldrich. Sol-
vents were dried and distilled under argon before use by
standard methods. Carbon, hydrogen, and nitrogen analyses
were performed with a Perkin-Elmer 2400 microanalyzer. IR
spectra were recorded with a Nicolet 550 spectrophotometer.
Mass spectra were recorded with a VG Autospec double-
focusing mass spectrometer operating in the FAB+ mode. Ions
were produced with the standard Cs+ gun at ca. 30 kV, and
3-nitrobenzyl alcohol (NBA) was used as matrix. Molecular
[RhCl(dppe)(Ph2PBnIm)] (4). Solid Ph2PBnIm (25.6 mg,
0.073 mmol) was added to a solution of [Rh2(µ-Cl)2(dppe)2] (39.0
mg, 0.036 mmol) in dichloromethane (2 mL). After 10 min the
solution was concentrated and layered with hexanes (15 mL)
to render a crystalline yellow solid, which was separated by
decantation, washed with hexane, and vacuum-dried. Yield:
61 mg (96%). Anal. Calcd for C48H43N2ClP3Rh: C, 65.58; H,
1
4.93; N, 3.19. Found: C, 65.50; H, 4.90; N, 3.36. H NMR (25
1
°C, CD2Cl2) (assigned from the H-31P spectrum): δ 7.96 (t,
b
JP -H ) JH-H ) 9.2 Hz, 4H, dppe), multiplets from 7.53 to 7.00
c
(32H, Ph+Im), 6.78 (s, 1H, Im), 5.36 (d, JP -H ) 2.0 Hz,
CH2Ph), 2.13, 2.05, 1.97, and 1.90 (m, 1H each, Ph2Pa(CH2)2Pb-
Ph2). 31P{1H} NMR (25 °C, CD2Cl2): δ 74.1 (dt, JP -P ) JP -P
a
b
a
c
) 34 Hz, JP -Rh ) 184 Hz, Ph2Pa(CH2)2PbPh2), 60.2 (ddd, JP -P
a
b
c
) 352 Hz, JP -P ) 34 Hz, JP -Rh ) 143 Hz, Ph2Pa(CH2)2Pb-
(22) Van der Ent, A.; Onderdelinden, A. L. Inorg. Synth. 1990, 28,
91.
(23) Giordano, G.; Crabtree, R. H. Inorg. Synth. 1990, 28, 88.
(24) Burini, A.; Pietroni, R. B.; Galassi, R.; Valle, G.; Caloggero, S.
Inorg. Chim. Acta 1995, 229, 299.
b
a
b
c
b
c
a
c
Ph2), 13.3 (ddd, JP -P ) 352 Hz, JP -P ) 34 Hz, JP -Rh ) 128
Hz, Ph2PcBnIm). MS (FAB+): 879 (6%, M+), 843 (100%, M -
Cl+).

Reactions of Phosphine Ligands with Ir Complexes
Organometallics, Vol. 24, No. 6, 2005 1111
Table 2. Crystal Data and Structure Refinement
for 1
[IrHCl(Ph2PCHPPh2)(dppm)] (5). Solid dppm (153.8 mg,
0.40 mmol) was added to a solution of [Ir2(µ-Cl)2(coe)4] (89.6
mg, 0.10 mmol) in toluene (7 mL). The initial orange solution
turned dark red and immediately evolved to a pale yellow
solution. After stirring for 30 min the solution was evaporated
to ca. 2 mL and carefully layered with hexane (20 mL) to
render a pale yellow microcrystalline solid in 3 days at room
temperature. The solid was filtered, washed with hexane, and
vacuum-dried. Yield: 150 mg (75%). Anal. Calcd for the
toluene solvate C57H52ClP4Ir: C, 63.39; H, 4.81. Found: C,
formula
Cl Ir P2 N4 C44 H38
fw
912.37
cryst syst
monoclinic
space group
P21/c
a, Å
10.284(4)
b, Å
23.343(5)
c, Å
16.066(3)
â, deg
97.56(3)
V, Å3
3823(2)
1
63.05; H, 4.68. H{31P} NMR (25 °C, C6D6): δ 7.85-7.70 (m,
Z
4
Dcalcd, g cm-3
1.585
40H, Ph), 5.14 (δA, 1H) and 5.04 (δB, JA-B ) 14.4 Hz, 1H) (CH2),
4.14 (s, 1H, CH), -17.58 (s, 1H, Ir-H). 31P{1H} NMR (25 °C,
C6D6): δ -55.7 (m, corresponding to an AA′BB′ spin system,
which appears as an apparent AB spin system: δA ) -50.8,
δB ) -60.6 JA-B ) 338 Hz). 13C{1H}-apt NMR (25 °C, C6D6):
δ 50.9 (t, JC-P ) 24 Hz, CH2), 25.2 (tt, JC-P ) 66 and 5 Hz,
CH). MS (FAB+): 997 (100%, M + H+), 961 (42%, M - Cl+).
[IrHCl(dppm)2]BF4. To a suspension of 5 (48 mg, 0.048
mmol) in diethyl ether (4 mL) was added HBF4‚Et2O (6.6 µL,
0.048 mmol) to give a white solid. The liquid was decanted,
and the solid was washed with diethyl ether and vacuum-
dried. Yield: 43 mg (83%). Anal. Calcd for C50H45ClP4IrBF4:
F(000)
1816
µ, cm-1
36.83
no. of reflns collected and unique
no. of obsd reflns [I>2σ(I)]
no. of params
4265, 4092 [R(int) ) 0.0894]
1965
302
final R indices [I > 2σ(I)]a
R1 ) 0.0370, wR2 ) 0.0822
R1 ) 0.1371, wR2 ) 0.1413
R indices (all data)a
a R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) [∑[w(Fo2 - Fc2)2]/∑[w(Fo2)2]]1/2
.
solution. The solution was concentrated to ca. 2 mL and
layered with diethyl ether (15 mL) to render an off-white solid
overnight. The mother liquors were decanted, and the solid
was washed with diethyl ether (2 × 5 mL) and vacuum-dried.
Yield: 133 mg (71%). Anal. Calcd for C35H30N2Cl3P2Ir: C,
50.10; H, 3.60; N, 3.34. Found: C, 50.34; H, 3.52; N, 3.17.
1H{31P} NMR (25 °C, CDCl3) (assigned from the 1H,1H-COSY
spectrum): δ 9.97 (d, J ) 5.9 Hz, 1H, PyPa), 9.10 (d, J ) 5.2
Hz, 1H, PyPb), 8.29 (t, J ) 7.7 Hz, 1H, PyPa), 8.14 (m, 4H,
PyPa+PyPb+PhoPb), 7.95 (d, J ) 7.8 Hz, 2H, Ph′oPa), 7.94 (t, J
) 5.5 Hz, 1H, PyPb), 7.60 (m, 2H, PyPa+PhpPb), 7.53 (m, 3H,
PhmPb+Ph′pPa), 7.40 (m, 5H, PyPb+PhpPa+Ph′mPa+Ph′pPb),
7.23 (m, 4H, PhmPa+Ph′mPb), 7.12 (d, J ) 7.1 Hz, 2H, Ph′oPb),
6.24 (d, J ) 7.7 Hz, 2H, PhoPa), 6.18 (δA, 1H) and 5.37 (δB,
JA-B ) 12.1 Hz, 1H) (Ir-CH2Cl). 31P{1H} NMR (25 °C,
CDCl3): δ 8.3 (d, J(PP) ) 15 Hz, Pb), -60.7 (d, J(PP) ) 15 Hz,
Pa). 13C{1H} NMR (25 °C, CDCl3): δ 44.7 (br s, Ir-CH2Cl).
MS (FAB+): 803 (100%, M - Cl+).
Crystal Structure Determination of Complex 1. The
crystals of 1 were rather small in size and of poor quality and
diffracted weakly. The intensity data of 1 were collected at
room temperature on a Philips PW1100 single-crystal diffrac-
tometer using graphite-monochromated Mo KR radiation.
Crystallographic and experimental details for the structure
are summarized in Table 2. A correction for absorption was
made [maximum and minimum value for the transmission
coefficient was 1.000 and 0.775].25 The structure was solved
by Patterson and Fourier methods and refined by full-matrix
least-squares procedures (based on Fo2) (SHELX-97)26 first with
isotropic and then with anisotropic thermal parameters in the
last cycles of refinement for all the non-hydrogen atoms except
the carbon atoms of the phenyl rings. The hydrogen atoms
were introduced into geometrically calculated positions and
refined riding on the corresponding parent atoms except the
hydride H1, which was localized in the ∆F map.
1
C, 55.39; H, 4.18. Found: C, 55.37; H, 4.08. H NMR (25 °C,
HDA): δ 7.49 (m, 24H, Ph), 7.33 (m, 16H, Ph), 5.80 (m, 2H,
CH2P), 5.58 (m, 2H, CH2P), -16.17 (quint, JH-P ) 12, 1 Hz,
Ir-H). 31P{1H} NMR (25 °C, HDA): δ -54.6 (s).
[Ir(dppe)2][IrCl2(coe)2] (6). To a solution of [Ir2(µ-Cl)2-
(coe)4] (105.5 mg, 0.118 mmol) in 1,2-dimethoxyethane (4 mL)
was slowly added via cannula a solution of dppe (96.7 mg, 0.24
mmol) in the same solvent. After 1 h stirring the orange solid
was filtered, washed with diethyl ether, and vacuum-dried.
Yield: 160 mg (96%). Anal. Calcd for C68H76Cl2P4Ir2: C, 55.46;
H, 5.20. Found: C, 55.51; H, 5.08. 1H NMR (25 °C, HDA)
1
(assigned from the H,1H-COSY spectrum): δ 7.37 (m, 20H,
Ph), 2.29 (m, 4H, CH2) (dppe); 5.12 (q, JH-H ) 12.2 Hz, 2H),
1.87 (dd, JH-H ) 13.9, 1.9 Hz, 2H), 1.48 (m, 6H) and 1.28 (m,
4H) (coe). 31P{1H} NMR (25 °C, HDA): δ 49.8 (s, dppe). MS
(FAB+): 989 (100%, M+).
[Ir(O2)Cl(Ph2PPy)2] (7). A solution of [IrCl(Ph2PPy)2] (2)
(151.0 mg, 0.20 mmol) in acetone (10 mL) was maintained
under an oxygen atmosphere for 30 min. The initial red
solution turned pale yellow in a few minutes and a yellow solid
precipitated. The solid was filtered, washed with cold acetone
(2 × 5 mL), and vacuum-dried. Yield: 153 mg (97%). Anal.
Calcd for C34H28N2ClO2P2Ir: C, 51.94; H, 3.59; N, 3.56.
Found: C, 51.91; H, 3.97; N, 3.21. IR (KBr, cm-1): ν(O-O)
844. 1H NMR (25 °C, CDCl3): δ 9.07 (t, J ) 4.0 Hz, 1H); from
7.88 to 6.92 (m, 27H). 31P{1H} NMR (25 °C, CDCl3): δ -20.0
(br s, Pb), -67.0 (d, JP-P ) 22 Hz, Pa). MS (FAB+): 787 (15%,
M+), 754 (100%, M - O2+).
[Ir(H)2Cl(Ph2PPy)3] (8). The addition of solid Ph2PPy
(164.7 mg, 0.62 mmol) to a suspension of [Ir2(µ-Cl)2(cod)2] (70.0
mg, 0.10 mmol) in acetone (7 mL) caused the immediate
formation of an orange solution. The solution was maintained
for 1 h under a hydrogen atmosphere, leading to a pale yellow
solution, which was concentrated to ca. 2 mL. Addition of
hexane (10 mL) under vigorous stirring gave a pale yellow solid
that was filtered, washed with hexane (2 × 5 mL), and
vacuum-dried. Yield: 195 mg (92%). Anal. Calcd for C51H44N3-
ClP3Ir: C, 60.08; H, 4.35; N, 4.12. Found: C, 59.95; H, 4.30;
N, 3.93. 1H NMR (25 °C, C6D6): δ 8.36-6.13 (42H), -9.54 (dtd,
JH-Pa ) 129.6 Hz, JH-Pb ) 19.8 Hz, JH-H ) 5.1 Hz, 1H, Ha-
Acknowledgment. The financial support from Min-
isterio de Ciencia y Tecnolog´ıa (MCyT(DGI)/FEDER)
Projects BQU2002-0074 and BQU2003-05412 is grate-
fully acknowledged. S.J. thanks Diputacion General de
Arago´n (DGA) for a fellowship.
Supporting Information Available: An X-ray crystal-
lographic file, in CIF format, containing full details of the
structural analyses of 1. This material is available free of
charge via the Internet at http://pubs.acs.org.
Ir), -20.27 (qd, JH-P ) 13.5 Hz, JH-H ) 5.1 Hz, 1H, Hb-Ir).
b
31P{1H} NMR (25 °C, C6D6): δ 14.3 (d, JP-P ) 15 Hz, 2P, Pb),
1.94 (t, JP-P ) 15 Hz, 1P, Pa). MS (FAB+): 984 (43%, M -
OM049142I
Cl+), 719 (100%, Ir(Ph2PPy)2
)
+
[IrCl2(η1-CH2Cl)(Ph2PPy)2] (9). To a suspension of [Ir2(µ-
Cl)2(coe)4] (100.0 mg, 0.11 mmol) in dichloromethane (5 mL)
was added Ph2PPy (117.5 mg, 0.45 mmol). The resulting red
solution was stirred at 35 °C for 2 h to give a pale orange
(25) (a) Walker N.; Stuart D. Acta Crystallogr. 1983, A39, 158. (b)
Ugozzoli F. Comput. Chem. 1987, 11, 109.
(26) Sheldrick, G. M. SHELX-97. Programs for Crystal Structure
Analysis (Release 97-2); Institu¨t fu¨r Anorganische Chemie der Uni-
versita¨t: Tammanstrasse 4, D-3400 Go¨ttingen, Germany, 1998.