Dppm and hydrido-bridged dinuclear complexes of iridium. Synthesis and structures of [(IrCp*)2(u-dppm)(u-H)(u-X)]2+ (X = Cl, OMe, OH, or H)

Article abstract of DOI:10.1039/b001239o

Reaction of [IrCp*Cl(u-H)]21 (Cp* = pentamethylcyclopentadienyl) with two equivalents of bis(diphenylphosphino)methane (dppm) gave an unidentate dppm complex IrCp*(H)(Cl)(dppm-/)) 2. This reacted with a half equivalent of [IrCp*CI(u-CI)]2 3 to give a dppm-bridged dinuclear complex (Cl)(H)Cp*Ir(n-dppm)IrCp*Cl2 4, in which the two metal centers are distal. Reaction of 4 with two equivalents of AgOTf (OTf = O3SCF3) gave a dppm, hydride and chloride-bridged diiridium complex [(IrCp*)2(u-dppm)(u-H)(u-Cl)][OTf]2 5a. Complex 5a reacted with sodium methoxide in methanol to give [(IrCp*)2(u-dppm)(u-H)(u-OMe)][OTf]2 6a. This reacted with water in refiuxing acetone to give a diiridium complex [(IrCp*)2(u-dppm)(u-H)(n-OH)][OTf]2 7a. Heating complex 6a in refiuxing toluene gave [(IrCp*)2(u-dppm)(n-H)2][OTf]2 8a. The structures of the anion exchanged complexes [(IrCp*)2(u-dppm)(u-H)(u-X)][BPh4]2 [X = Cl 5b, OMe 6b, OH 7b or H 8b] have been confirmed by X-ray analysis. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/b001239o

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dppm and hydrido-bridged dinuclear complexes of iridium.
Synthesis and structures of [(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-X)]2؉
(X ؍ Cl, OMe, OH, or H)
Ken-ichi Fujita,* Taro Hamada and Ryohei Yamaguchi*
Department of Natural and Environmental Sciences, Faculty of Integrated Human Studies and
Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501,
Japan
Received 15th February 2000, Accepted 20th April 2000
Published on the Web 23rd May 2000
Reaction of [IrCp*Cl(µ-H)]2 1 (Cp* = pentamethylcyclopentadienyl) with two equivalents of bis(diphenylphosphino)-
methane (dppm) gave an unidentate dppm complex IrCp*(H)(Cl)(dppm-P) 2. This reacted with a half equivalent of
[IrCp*Cl(µ-Cl)]2 3 to give a dppm-bridged dinuclear complex (Cl)(H)Cp*Ir(µ-dppm)IrCp*Cl2 4, in which the two
metal centers are distal. Reaction of 4 with two equivalents of AgOTf (OTf = O3SCF3) gave a dppm, hydride and
chloride-bridged diiridium complex [(IrCp*)2(µ-dppm)(µ-H)(µ-Cl)][OTf]2 5a. Complex 5a reacted with sodium
methoxide in methanol to give [(IrCp*)2(µ-dppm)(µ-H)(µ-OMe)][OTf]2 6a. This reacted with water in refluxing
acetone to give a diiridium complex [(IrCp*)2(µ-dppm)(µ-H)(µ-OH)][OTf]2 7a. Heating complex 6a in refluxing
toluene gave [(IrCp*)2(µ-dppm)(µ-H)2][OTf]2 8a. The structures of the anion exchanged complexes [(IrCp*)2-
(µ-dppm)(µ-H)(µ-X)][BPh4]2 [X = Cl 5b, OMe 6b, OH 7b or H 8b] have been confirmed by X-ray analysis.
Introduction
(1)
Recently, much attention has focused on the chemistry of
multinuclear transition-metal complexes1 with the metal atoms
kept in close proximity in expectation of co-operative reactivi-
ties of those metals, which could not be realized by a single
metal center. Bis(diphenylphosphino)methane (dppm) is one
of the most commonly adopted ligands in order to lock the
metal atoms in position and to prevent dissociation to mono-
nuclear species.2 While many hundreds of complexes contain-
ing two bridging dppm, M(µ-dppm)2M, have been reported,3
eqn. (1). Formation of 2 was spectroscopically confirmed, but
isolation was not carried out. Addition of a half equivalent of
chloro-bridged dinuclear complex [IrCp*Cl(µ-Cl)]2 3 to the
solution of 2 gave a dppm-bridged dinuclear complex (Cl)(H)-
Cp*Ir(µ-dppm)IrCp*Cl2 4 in 85% yield, (eqn. 1). The 1H NMR
spectrum of 4 showed two resonance signals for non-equivalent
Cp* protons (δ 1.28 and 1.53). A signal for hydride was
observed at δ Ϫ13.59 as doublet [2J(PH) = 36.6 Hz]. Since the
solubility of 4 in common organic solvents was extremely poor,
13C-{1H} and 31P-{1H} NMR could not be measured. Consider-
ing the structure of the closely related complex (IrCp*Cl2)2-
(µ-dppm), reported by Keim and co-workers,7 the two iridium
centers in 4 would not be in close proximity and there would be
no interaction between them.
there have been relatively few dinuclear complexes with a single
bridging dppm ligand.4
On the other hand, the chemistry of mononuclear iridium
complexes is also of interest, because of their roles in the acti-
vation of small molecules.5 Especially, cyclopentadienyl (Cp)
and pentamethylcyclopentadienyl (Cp*) iridium complexes are
of great interest, and their remarkable reactivities (such as
carbon–hydrogen bond activation) have been revealed.6 Investi-
gationsonmononuclearcyclopentadienylandpentamethylcyclo-
pentadienyl iridium complexes have widely been performed and
their fundamental properties revealed, however relatively little
is known about dinuclear cyclopentadienyl and pentamethyl-
cyclopentadienyl iridium complexes.
In this paper we report the synthesis and structures of novel
dppm and hydrido-bridged diiridium complexes with a penta-
methylcyclopentadienyl ligand on each iridium center. These
complexes are, to the best of our knowledge, the first examples
of dppm-bridged diiridium complexes with pentamethyl-
cyclopentadienyl ligands and two iridium atoms in close
proximity.
To eliminate chloride ligands and generate a co-ordinatively
unsaturated species, reactions of complex 4 with silver salt were
carried out. Treatment with two equivalents of AgOTf (OTf =
triflate, i.e. trifluoromethanesulfonate) in THF gave a dppm,
hydride and chloride-bridged diiridium complex [(IrCp*)2-
(µ-dppm)(µ-H)(µ-Cl)][OTf]2 5a in 79% yield, eqn. (2). 1H,
(2)
Results and discussion
Synthesis of [(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-Cl)][OTf]2 5a
Reaction of the hydrido-bridged dinuclear complex [IrCp*Cl-
(µ-H)]2 1 with two equivalents of dppm in tetrahydrofuran
gave an unidentate dppm complex IrCp*(H)(Cl)(dppm-P) 2,
13C-{1H} and 31P-{1H} NMR data of 5a are summarized
in Table 1. These data indicated that 5a has a symmetrical
DOI: 10.1039/b001239o
J. Chem. Soc., Dalton Trans., 2000, 1931–1936
This journal is © The Royal Society of Chemistry 2000
1931

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Table 1 NMR Spectral data (in CDCl3) for compounds 5a–8aa
Signal
1H
5a
6a
7a
8a
Ir–H–Ir
C5Me5
PCH2P
Ϫ18.42 [1 H, t, 2J(PH) 11.9]
1.75 (30 H, s)
Ϫ17.93 [1 H, t, 2J(PH) 11.9]
1.72 (30 H, s)
Ϫ17.76 [1 H, t, 2J(PH) 11.9]
1.77 (30 H, s)
Ϫ17.24 [2 H, t, 2J(PH) 9.2]
1.62 (30 H, s)
2.82 [1 H, td, 2J(PH) 11.9,
2J(HH) 13.8]
1.45 (1 H, m)
1.73 (1 H, overlapped by C5Me5)
3.47 [2 H, t, 2J(PH) 11.9]
3.41 [1 H, td, 2J(PH) 10.1,
2J(HH) 13.8]
3.48 (1 H, m)
4.38 (3 H, s)
3.29 [1 H, td, 2J(PH) 11.9, 2J(HH)
12.8]
OMe
OH
Ph
6.08 (1 H, s)
7.27–7.52 (20 H)
7.27–7.55 (20 H)
7.21–7.56 (20 H)
7.24–7.55 (20 H)
13C-{1H}
C5Me5
PCH2P
OMe
C5Me5
CF3SO3
Ph
10.1 (s)
9.9 (s)
9.9 (s)
10.5 (s)
27.8 [t, 1J(PC) 29.0]
19.0 [t, 1J(PC) 29.0]
77.2 (s)
23.3 [t, 1J(PC) 26.9]
40.2 [t, 1J(PC) 31.3]
99.1 (s)
96.8 (s)
96.1 (s)
99.9 (s)
121.0 [q, 1J(FC) 321]
121.8–135.8
121.0 [q, 1J(FC) 321]
123.0–135.4
120.9 [q, 1J(FC) 321]
123.2–135.7
121.0 [q, 1J(FC) 321]
126.1–134.7
31P-{1H}
P
11.3 (s)
16.9 (s)
14.2 (s)
41.7 (s)
a Given as chemical shift (δ) [relative intensity, multiplicity, J/Hz].
1
structure in solution. The H NMR spectrum showed a single
NMR data of 7a are summarized in Table 1. In 1H NMR a new
signal appeared at δ 6.08, which was assigned to hydroxy proton
because it disappeared upon adding a drop of D2O. Although
the proton of a hydroxy group bridging two metal centers is
ordinarily observed in the upfield region,3i,j,4f that of 7a was
found at extremely low field. The reason for this low-field shift
is not clear. One possible explanation would be that deproton-
ation of the hydroxy group could occur affording a oxide
bridged complex in solution, but no clear evidence was
given by crystal structure analysis of 7b (see below). In
31P-{1H} NMR a signal for phosphorus of dppm was found at
δ 14.2.
resonance signal of the Cp* protons at δ 1.75 together with
those due to the non-equivalent methylene protons of dppm
(δ 2.82 and 3.41) and phenyl protons (δ 7.27–7.55). A signal
for metal hydride was observed at δ Ϫ18.42 as a triplet
[2J(PH) = 11.9 Hz] coupling to the two phosphorus atoms,
indicating that the hydride bridges the two metal centers. In
31P-{1H} NMR only a single resonance signal at δ 11.3 was
observed.
Synthesis of [(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-OMe)][OTf]2 6a
The complex 5a reacted with sodium methoxide in methanol
to give a dppm, hydride and methoxo-bridged diiridium com-
plex [(IrCp*)2(µ-dppm)(µ-H)(µ-OMe)][OTf]2 6a in 83% yield,
eqn. (3). 1H, 13C-{1H} and 31P-{1H} NMR data are summarized
Synthesis of [(IrCp*)2(ꢀ-dppm)(ꢀ-H)2][OTf]2 8a
Heating complex 6a in refluxing toluene for 17 hours gave a
dppm and dihydrido-bridged complex [(IrCp*)2(µ-dppm)-
(µ-H)2][OTf]2 8a in 82% yield, eqn. (5). 1H, 13C-{1H} and
(3)
(5)
in Table 1. Signal patterns for Cp*, dppm and metal hydride of
6a were similar to those of 5a, suggesting that 6a also has a
symmetrical structure. A signal for bridging methoxy group was
1
31P-{1H} NMR data of 8a are summarized in Table 1. In H
1
found at δ 4.38 in H NMR, at δ 77.2 in 13C-{1H} NMR. In
NMR the signal for the methoxy group of the starting complex
6a disappeared. The bridging hydrides were found at δ Ϫ17.24
as a triplet [2J(PH) = 9.2 Hz], which integrated to two hydrides.
A single signal for the methylene protons of dppm in 8a was
found at δ 3.47 as a triplet [2J(PH) = 11.9 Hz], in contrast with
the result that two signals were obtained for 5a, 6a and 7a. In
31P-{1H} NMR a signal for phosphorus of dppm appeared at
δ 41.7, which shifted to lower field of those of 5a, 6a and 7a. It
has been reported that the NMR signal of phosphorus
incorporated in a five-membered ring shifts to lower field.8
Considering the crystal structure determination of 8b (see
below), the shorter distance between the two iridium centers in
8a than those in 5a, 6a and 7a could make it possible to con-
struct a five-membered ring by dppm and two iridium atoms. In
order to ascertain the origin of the second hydride, synthesis of
8a was performed using toluene-d8 as a solvent. No incorpor-
ation of deuterium was observed. So the formation of 8a from
6a would proceed via β-hydrogen elimination from bridging
methoxy ligand, although formaldehyde could not be detected.
31P-{1H} NMR a signal for phosphorus of dppm appeared at
δ 16.9. The reaction of 5a with sodium methoxide would pro-
ceed via substitution of chloride ligand by methoxide. Reaction
of 5a with sodium ethoxide was also attempted, but a very
complicated mixture of several complexes was obtained.
Reaction of complex 6a with water: formation of [(IrCp*)2-
(ꢀ-dppm)(ꢀ-H)(ꢀ-OH)][OTf]2 7a
The bridging methoxy ligand in 6a was substituted by hydroxy
ligand in the reaction of 6a with water in refluxing acetone
to give a diiridium complex [(IrCp*)2(µ-dppm)(µ-H)(µ-OH)]-
1
[OTf]2 7a in 35% yield, eqn. (4). H, 13C-{1H} and 31P-{1H}
(4)
1932
J. Chem. Soc., Dalton Trans., 2000, 1931–1936

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Fig. 1 An ORTEP9 drawing of the cation [(IrCp*)2(µ-dppm)(µ-H)-
(µ-Cl)]2ϩ in complex 5b. Hydrogen atoms are omitted for clarity.
Fig. 2 An ORTEP drawing of the cation [(IrCp*)2(µ-dppm)(µ-H)-
(µ-OMe)]2ϩ in the complex 6b. Hydrogen atoms are omitted for clarity.
In contrast to the present reaction, Riera and co-workers have
reported that the reaction of a dppm and dihydrido-bridged
dimanganese complex with aldehydes afforded dppm, hydride
and alkoxo-bridged dimanganese complexes.4b
Crystal structure analysis of dppm and hydrido-bridged diiridium
complexes [(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-X)]2؉ 5–8
To obtain crystals suitable for X-ray analysis, the triflate com-
plexes 5a–8a were converted into tetraphenylborate complexes
5b–8b by anion exchange reaction with sodium tetraphenyl-
borate, eqn. (6). NMR spectra of 5b–8b were essentially the
(6)
Fig. 3 An ORTEP drawing of the cation [(IrCp*)2(µ-dppm)(µ-H)-
(µ-OH)]2ϩ in the complex 7b. Hydrogen atoms except for hydroxy
proton are omitted for clarity.
same as those of the corresponding triflate complexes. The
structures of 5b–8b were elucidated through X-ray diffraction
studies. The molecular geometry and atom-numbering systems
are shown in Figs. 1–4, and the results obtained are summarized
in Tables 2 and 3.
The complex 5b contains a diiridium core bridged by dppm
and a chlorine atom. Although the location of the bridging
hydrogen atom could not be determined, it should be situated
on the Ir(1)–Cl(1)–Ir(2) plane, which is nearly perpendicular to
the plane defined by the phosphorus and iridium atoms. The
geometry around each iridium center is described as three-
legged piano stool, which is general in Cp*IrIII complexes,
assuming that the bridging hydride exists at the position men-
tioned above. The dppm methylene group is folded toward the
bridging chloride atom. The complex 5b would be a 34-electron
one, if the bridging hydride is regarded as a two-electron ligand.
The iridium–iridium distance is relatively large (3.0079(9) Å).
This value is outside the range of normal iridium–iridium
bonding distances, thereby the degree of direct metal–metal
interaction is ambiguous.
The structures of 6b, 7b and 8b are similar to that of 5b
except for the bridging group X. It should be noted that the
distances between the two iridium centers decrease in the
order 5b > 6b, 7b > 8b. In complex 6b the carbon atom of the
bridging methoxo group is directed out of the Ir(1)–O(1)–Ir(2)
plane. The Ir(1)–O(1) and Ir(2)–O(1) distances are 2.167(6) and
2.144(6) Å, respectively. In 7b the Ir(1)–O(1) and Ir(2)–O(1)
distances are equal [2.130(5) Å]. The hydrogen atom of the
Fig. 4 An ORTEP drawing of the cation [(IrCp*)2(µ-dppm)(µ-H)2]2ϩ
in the complex 8b. Hydrogen atoms except for metal hydrides are
omitted for clarity.
hydroxy group was not refined well, nonetheless it was clearly
defined on Fourier difference maps with O(1)–H(93) 0.99 Å. No
significant interaction of the hydroxy hydrogen atom H(93)
J. Chem. Soc., Dalton Trans., 2000, 1931–1936
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Table 2 Selected interatomic distances (Å) and angles (Њ) in the
complexes 5b–8b
Preparations
IrCp*(H)(Cl)(dppm-P) 2. A mixture of compound 1 (0.504 g,
0.692 mmol) and dppm (0.555 g, 1.44 mmol) was placed in a
reactor. Tetrahydrofuran (7 cm3) was added and the solution
stirred at room temperature for 20.5 h. Formation of 2 was
5b
6b
7b
8b
Ir(1) ؒ ؒ ؒ Ir(2)
Ir(1)–P(1)
Ir(2)–P(2)
Ir(1)–Cl(1)
Ir(2)–Cl(1)
Ir(1)–O(1)
Ir(2)–O(1)
P(1)–C(1)
P(2)–C(1)
O(1)–C(94)
3.0079(9)
2.308(3)
2.313(3)
2.406(3)
2.423(3)
2.953(1)
2.314(2)
2.307(2)
2.9334(5)
2.309(2)
2.306(2)
2.818(1)
2.302(2)
2.296(2)
confirmed by H, 13C-{1H} and 31P-{1H} NMR, but isolation
1
was not carried out. δH (C6D6) Ϫ12.87 (1 H, d, 2J(PH) 38.5 Hz,
Ir-H), 1.62 (15 H, s, C5Me5), 3.87–4.08 (2 H, m, PCH2P) and
6.99–8.11 (20 H, Ph). δC (C6D6) 9.3 (s, C5Me5), 32.3 [dd, 1J(PC)
2.167(6)
2.144(6)
1.832(8)
1.825(8)
1.21(1)
2.130(5)
2.130(5)
1.836(8)
1.832(8)
2
36.2, 32.1, PCH2P], 92.7 [d, J(PC) 3.1 Hz, C5Me5] and 127.1–
2
140.7 (Ph). δP (C6D6) Ϫ23.7 [d, J(PP) 59.5, IrPCH2P] and 7.4
1.84(1)
1.83(1)
1.813(9)
1.838(9)
[d, 2J(PP) 59.5 Hz, IrPCH2P].
(Cl)(H)Cp*Ir(ꢀ-dppm)IrCp*Cl2 4. To a tetrahydrofuran solu-
tion of compound 2 generated in situ from 1 (0.692 mmol) and
dppm (1.44 mmol), 3 (0.552 g, 0.693 mmol) was added and the
solution stirred at room temperature for 30 min. The resulting
yellow precipitate was filtered off, washed with diethyl ether (12
cm3), and dried to give 4 (1.34 g, 85%) as a yellow powder, mp
116.4 ЊC (decomp.) (Found: C, 46.63; H, 4.67; Cl, 9.21%.
C45H53Cl3Ir2P2 requires C, 47.14; H, 4.66; Cl, 9.28%); ν/cmϪ1
Ir(2)–Ir(1)–P(1)
Ir(2)–Ir(1)–Cl(1)
Ir(2)–Ir(1)–O(1)
P(1)–Ir(1)–Cl(1)
P(1)–Ir(1)–O(1)
Ir(1)–Ir(2)–P(2)
Ir(1)–Ir(2)–Cl(1)
Ir(1)–Ir(2)–O(1)
P(2)–Ir(2)–Cl(1)
P(2)–Ir(2)–O(1)
Ir(1)–Cl(1)–Ir(2)
Ir(1)–O(1)–Ir(2)
Ir(1)–P(1)–C(1)
Ir(2)–P(2)–C(1)
P(1)–C(1)–P(2)
Ir(1)–O(1)–C(94)
Ir(2)–O(1)–C(94)
89.06(7)
51.72(7)
92.22(6)
46.4(1)
90.31(5)
46.5(1)
91.53(7)
91.7(1)
81.7(2)
90.06(6)
86.6(2)
92.33(5)
91.98(7)
51.21(6)
93.35(7)
47.1(2)
86.7(2)
46.5(1)
81.6(2)
87.1(1)
2
(KBr) 2081w (Ir-H). δH (CDCl3) Ϫ13.59 [1 H, d, J(PH) 36.6,
Ir-H], 1.28 (15 H, s, C5Me5), 1.53 (15 H, s, C5Me5), 4.62 [2 H, t,
77.07(8)
2J(PH) 9.2 Hz, PCH2P] and 6.94–7.51 (20 H, Ph).
86.5(2)
112.6(3)
111.3(3)
114.0(4)
118.9(7)
120.7(7)
87.0(2)
110.8(3)
112.7(2)
113.1(4)
112.2(3)
113.0(3)
113.5(5)
111.3(3)
112.8(3)
112.4(5)
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-Cl)][OTf]2 5a. A mixture of com-
pound 4 (0.505 g, 0.440 mmol) and AgOTf (0.227 g, 0.883
mmol) was placed in a reactor. Tetrahydrofuran (20 cm3) was
added, and the solution stirred at room temperature for 35 min.
After evaporation of the solvent the residue was chromato-
graphed on silica gel. Elution with methanol followed by evap-
oration of the solvent gave 5a (0.479 g, 79%) as a red-orange
powder, mp 237.3 ЊC (decomp.) (Found: C, 40.47; H, 3.69; Cl,
2.59%. C47H53ClF6Ir2O6P2S2 requires C, 41.09; H, 3.89; Cl,
2.58%).
with other atoms (as in hydrogen bonding) were observed, while
1H NMR spectra of 7a and 7b in solution show signals for the
hydroxy proton at unusually lower field [δ 6.08 (7a), 5.04 (7b)].
In the complex 8b the iridium–iridium distance is 2.818(1) Å,
significantly shorter than that of 5b, in agreement with the
observation of a low-field shift in 31P-{1H} NMR of 8a and 8b
(see above). Two metal hydrides were located from Fourier
difference maps and the Ir(1)–H(1), Ir(1)–H(2), Ir(2)–H(1) and
Ir(2)–H(2) bond distances were 1.75, 1.99, 1.96 and 1.70 Å,
respectively. The complex 8b would be a 32-electron one, so
there should be bonding interaction between the two iridium
atoms.
In conclusion, novel dppm and hydrido-bridged dinuclear
complexes of iridium were prepared and their structures con-
firmed by X-ray analyses. These complexes are, to the best of
our knowledge, the first examples of dppm-bridged diiridium
complexes with the pentamethylcyclopentadienyl ligand and
two iridium atoms in close proximity. Since complexes 5–8
would generate co-ordinatively unsaturated species by bridge
splitting reaction, unique reactivities of the dinuclear com-
plexes are expected. Further investigation on the reactivities of
these complexes is in progress.
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-Cl)][BPh4]2 5b.
A mixture of
compound 5a (0.203 g, 0.148 mmol) and NaBPh4 (0.100 g,
0.292 mmol) was placed in a reactor. Methanol (5 cm3) was
added and the solution stirred at room temperature for 30 min.
The resulting orange product was filtered off, washed with
methanol (6 cm3) and dried. Extraction with acetone (17 cm3)
and recrystallization from acetone–diethyl ether gave 5b (0.174
g, 69%) as red crystals, mp 206.9 ЊC (decomp.) (Found: C,
64.87; H, 5.44; Cl, 2.16%. C93H93B2ClIr2P2 requires C, 65.16; H,
2
5.47; Cl, 2.07%). δH (acetone-d6) Ϫ18.37 [1 H, t, J(PH) 11.9,
Ir-H-Ir], 1.78 (30 H, s, C5Me5), 3.49 [2 H, t, 2J(PH) 11.0,
PCH2P], 6.74–6.91, 7.23–7.60 (60 H, Ph). δC (acetone-d6) 10.2
1
(s, C5Me5), 26.0 [t, J(PC) 30.0 Hz, PCH2P], 99.8 (s, C5Me5),
122.1–136.9, 164.2–165.4 (Ph). δP (acetone-d6) 11.8 (s).
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-OMe)][OTf]2 6a. To a solution of
compound 5a (0.535 g, 0.389 mmol) in methanol (25 cm3) was
added a solution of NaOMe (15.5 cm3, 35.2 M in methanol) at
room temperature and stirred for 2.2 h. After evaporation of
the solvent the residue was extracted with 15 cm3 of chloro-
form. Evaporation of the solvent gave 6a (0.439 g, 83%) as a red
powder, mp 109.8 ЊC (decomp.). Elemental analyses for 6a were
unsatisfactory because of a small amount of contaminant.
Experimental
All manipulations were performed under a dry argon atmos-
phere with standard Schlenk techniques. Melting points were
determined under air on a Yanagimoto micro melting point
apparatus. Elemental analyses were carried out at the Micro-
analysis Center of Kyoto University. Infrared spectra were
taken on a HORIBA FT-300 spectrometer, H, 13C-{1H} and
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-OMe)][BPh4]2 6b. Reaction of
compound 6a with NaBPh4 according to a similar procedure to
the above gave 6b as orange crystals, mp 109.1 ЊC (decomp.)
(Found: C, 66.03; H, 5.69%. C94H96B2Ir2OP2 requires C, 66.03;
H, 5.66%). δH (acetone-d6) Ϫ17.85 [1 H, t, 2J(PH) 11.9, Ir-H-Ir],
1.77 (30 H, s, C5Me5), 2.14 [1 H, td, 2J(PH) 11.9, 2J(HH) 13.8,
PCHHP], 3.36 [1 H, td, 2J(PH) 11.9, 2J(HH) 13.8 Hz, PCHHP],
4.42 (3 H, s, OMe) and 6.74–7.61 (60 H, Ph). δC (acetone-d6)
10.1 (s, C5Me5), 17.2 [t, 1J(PC) 30.0 Hz, PCH2P], 77.2 (s, OMe),
1
31P-{1H} spectra with JEOL EX-270 and A-500 spectrometers.
Solvents were distilled under an argon atmosphere with
appropriate drying agents (solvent/drying agent): tetrahydro-
furan/Na–benzophenone, diethyl ether/Na-benzophenone,
methanol/Mg, chloroform/P2O5, toluene/CaH2. The com-
pounds [IrCp*Cl(µ-H)]2 110 and [IrCp*Cl(µ-Cl)]2 311 were
prepared by literature methods. Other reagents were used as
obtained from commercial sources.
1934
J. Chem. Soc., Dalton Trans., 2000, 1931–1936

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Table 3 Summary of crystal data, collection data, and refinement of complexes 5b, 6b, 7b and 8b
5b
6b
7b
8b
Formula
M
Crystal system
Space group
C93H93B2ClIr2P2
1714.22
Monoclinic
P21/a
C94H96B2Ir2OP2
1709.80
Monoclinic
P21/a
C93H94B2Ir2OP2
1695.77
Monoclinic
P21/a
C93H94B2Ir2P2
1679.77
Monoclinic
P21/a
a/Å
b/Å
c/Å
26.484(7)
11.022(5)
27.760(5)
107.93(1)
7710(4)
4
26.481(9)
11.13(1)
27.771(9)
107.96(3)
7788(7)
4
26.435(2)
10.988(3)
27.771(2)
108.701(5)
7641(2)
4
26.362(6)
11.023(8)
27.701(8)
108.50(2)
7634(5)
4
β/Њ
V/Å3
Z
µ/cmϪ1
35.81
35.13
35.80
35.81
T/K
296
19013
291
19124
291
18752
296
18756
No. reflections measured
No unique data, Rint
No. reflections used
18614, 0.097
10359
18730, 0.045
8238
18365, 0.058
11263
18365, 0.080
11200
R
Rw
0.058
0.061
0.040
0.037
0.049
0.056
0.062
0.071
97.8 (s, C5Me5), 122.1–136.9, 164.2–165.4 (Ph). δP (acetone-d6)
17.6 (s).
atoms by full-matrix least-squares calculations. All refinements
were continued until all shifts were smaller than one-third of
the standard deviations of the parameters involved. Atomic
scattering factors and anomalous dispersion terms were taken
from ref. 14. The hydrogen atoms were located on idealized
positions except for that of the hydroxy group in 7b and metal
hydrides in 8b, which were defined on Fourier difference maps.
All hydrogen atoms were not refined. Metal hydrides in 5b–7b
were not located. The calculations were performed using the
program system TEXSAN.15
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-OH)][OTf]2 7a. A solution of
compound 6a (0.173 g, 0.126 mmol) in acetone (10 cm3) and
water (0.1 cm3) was refluxed for 24 h. After evaporation of the
solvent the residue was chromatographed on silica gel. Elution
with chloroform and methanol (4:1) followed by evaporation
of the solvent gave 7a (0.0595 g, 35%) as an orange powder, mp
238.5 ЊC (decomp.) (Found: C, 41.93; H, 3.93%. C47H54F6Ir2-
O7P2S2 requires C, 41.65; H, 4.02%).
CCDC reference number 186/1947.
See http://www.rsc.org/suppdata/dt/b0/b001239o/ for crystal-
lographic files in .cif format.
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)(ꢀ-OH)][BPh4]2 7b. Reaction of
compound 7a with NaBPh4 according to a similar procedure to
the above gave 7b as orange crystals, mp 219.2 ЊC (decomp.)
(Found: C, 65.69; H, 5.57%. C93H94B2Ir2OP2 requires C, 65.87;
References
2
H, 5.59%). δH (acetone-d6) Ϫ17.58 [1 H, t, J(PH) 11.9 Hz,
1 A. F. Heyduk and D. G. Nocera, Chem. Commun., 1999, 1519;
T. Iwasa, H. Shimada, A. Takami, H. Matsuzaka, Y. Ishii and
M. Hidai, Inorg. Chem., 1999, 38, 2851; M. V. Jiménez, E. Sola, A. P.
Martínez, F. J. Lahoz and L. A. Oro, Organometallics, 1999, 18,
1125; D. A. Vicic and W. D. Jones, Organometallics, 1999, 18, 134;
K. Tani, A. Iseki and T. Yamagata, Angew. Chem., Int. Ed., 1998, 37,
3381; M. A. Arthurs, J. Bickerton, S. R. Stobart and J. Wang,
Organometallics, 1998, 17, 2743; H. Matsuzaka, K. Ariga, H. Kase,
T. Kamura, M. Kondo, S. Kitagawa and M. Yamasaki,
Organometallics, 1997, 16, 4514; D. M. Heinekey, D. A. Fine and
D. Barnhart, Organometallics, 1997, 16, 2530; Z. Tang, Y. Nomura,
Y. Ishii, Y. Mizobe and M. Hidai, Organometallics, 1997, 16, 151.
2 R. J. Puddephatt, Chem. Soc. Rev., 1983, 99; B. Chaudret,
B. Delavaux and R. Poilblanc, Coord. Chem. Rev., 1988, 86, 191.
3 (a) R. A. Stockland, Jr., G. K. Anderson and N. P. Rath, J. Am.
Chem. Soc., 1999, 121, 7945; (b) J. R. Torkelson, R. McDonald and
M. Cowie, Organometallics, 1999, 18, 4134; (c) Y. Gao, J. Kuncheria,
G. P. A. Yap and R. J. Puddephatt, Chem. Commun., 1998, 2365;
(d) K.-B. Shiu, S.-W. Jean, H.-J. Wang, S.-L. Wang, F.-L.
Liao, J.-C. Wang and L.-S. Liou, Organometallics, 1997, 16, 114;
(e) F. A. Cotton, C. A. James and R. L. Luck, Inorg. Chem., 1991,
30, 4370; (f) S. J. Chen and K. R. Dunbar, Inorg. Chem.,
1990, 29, 529; (g) R. McDonald, B. R. Sutherland and M. Cowie,
Inorg. Chem., 1987, 26, 3333; (h) P. E. Fanwick, W. S. Harwood
and R. A. Walton, Inorg. Chem., 1987, 26, 242; (i) B. R. Sutherland
and M. Cowie, Organometallics, 1985, 4, 1637; (j) K.-W. Lee and
T. L. Brown, Organometallics, 1985, 4, 1025; (k) H. C. Aspinall
and A. J. Deeming, J. Chem. Soc., Chem. Commun., 1983, 838.
4 (a) M. A. Alvarez, M. E. García, V. Riera and M. A. Ruiz,
Organometallics, 1999, 18, 634; (b) F. J. G. Alonso, M. G. Sanz,
X. Y. Liu, A. Oliveira, M. A. Ruiz, V. Riera and C. Bois,
J. Organomet. Chem., 1996, 511, 93; (c) V. Riera, M. A. Ruiz,
F. Villafañe, Y. Jeannin and C. Bois, J. Organomet. Chem., 1988,
345, C4; (d) V. Riera, M. A. Ruiz, A. Tiripicchio and M. T.
Camellini, J. Organomet. Chem., 1986, 308, C19; (e) K.-W. Lee,
W. T. Pennington, A. W. Cordes and T. L. Brown, J. Am. Chem. Soc.,
1985, 107, 631; (f) K.-W. Lee, W. T. Pennington, A. W. Cordes and
T. L. Brown, Organometallics, 1984, 3, 404; (g) F. Faraone,
G. Bruno, S. L. Schiavo and G. Bombieri, J. Chem. Soc., Dalton
Ir-H-Ir], 1.77 (30 H, s, C5Me5), 2.31 (1 H, m, PCHHP), 3.36
(1 H, m, PCHHP), 5.04 (1 H, s, OH) and 6.74–7.65 (60 H, Ph).
δC (acetone-d6) 10.2 (s, C5Me5), 18.9 [t, 1J(PC) 27.9 Hz, PCH2P],
97.1 (s, C5Me5), 122.2–137.0, 164.3–165.5 (Ph). δP (acetone-d6)
15.6 (s).
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)2][OTf]2 8a. A suspension of com-
pound 6a (1.04 g, 0.759 mmol) in toluene (20 cm3) was refluxed
for 17 h. Evaporation of the solvent gave 8a (0.836 g, 82%) as a
brown powder, mp 249.8–253.5 ЊC. Elemental analyses for 8a
were unsatisfactory because of a small amount of contaminant.
[(IrCp*)2(ꢀ-dppm)(ꢀ-H)2][BPh4]2 8b. Reaction of compound
8a with NaBPh4 according to a similar procedure to the above
gave 8b as dark orange crystals, mp 223.5 ЊC (decomp.) (Found:
C, 66.05; H, 5.45%. C93H94B2Ir2P2 requires C, 66.50; H, 5.64%).
δH (acetone-d6) Ϫ17.16 [2 H, t, 2J(PH) 10.1, Ir-H-Ir], 1.64
2
(30 H, s, C5Me5), 3.85 [2 H, t, J(PH) 11.9 Hz, PCH2P] and
6.74–7.59 (60 H, Ph). δC (acetone-d6) 10.9 (s, C5Me5), 39.6 [t,
1J(PC) 33.1 Hz, PCH2P], 101.2 (s, C5Me5), 122.2–137.0, 164.4–
165.5 (Ph). δP (acetone-d6) 48.0 (s).
Crystallography
The crystal data and experimental details for compounds 5b,
6b, 7b and 8b are summarized in Table 3. Diffraction data were
obtained with a Rigaku AFC-7R diffractometer for 5b and
a Rigaku AFC-5S for 6b, 7b and 8b. The reflection inten-
sities were monitored by three standard reflections every 150
measurements. Reflection data were corrected for Lorentz-
polarization effects. Absorption corrections were empirically
applied. The structures were solved by heavy-atom Patterson
methods,12,13 and refined anisotropically for non-hydrogen
J. Chem. Soc., Dalton Trans., 2000, 1931–1936
1935

View Article Online
Trans., 1984, 533; (h) G. M. Dawkins, M. Green, A. G. Orpen and
F. G. A. Stone, J. Chem. Soc., Chem. Commun., 1982, 41.
5 G. J. Leigh and R. L. Richards, in Comprehensive Organometallic
Chemistry, eds. G. Wilkinson, F. G. A. Stone and E. W. Abel,
Pergamon, Oxford, 1982, vol. 5, p. 541; J. D. Atwood, in
Comprehensive Organometallic Chemistry II, eds. E. W. Abel,
F. G. A. Stone, G. Wilkinson and J. D. Atwood, Pergamon, Oxford,
1995, vol. 8, p. 303.
6 B. A. Arndtsen, R. G. Bergman, T. A. Mobley and T. H. Peterson,
Acc. Chem. Res., 1995, 28, 154 and references therein; B. A.
Arndtsen and R. G. Bergman, Science, 1995, 270, 1970.
7 W. Keim, P. Kraneburg, G. Dahmen, G. Deckers, U. Englert,
K. Linn, T. P. Spaniol and G. Raabe, Organometallics, 1994, 13,
3085.
10 D. S. Gill and P. M. Maitlis, J. Organomet. Chem., 1975, 87, 359.
11 J. W. Kang, K. Moseley and P. M. Maitlis, J. Am. Chem. Soc., 1969,
91, 5970.
12 PATTY, 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, 1992.
13 DIRDIF 94, P. T. Beurskens, G. Admiraal, G. Beurskens, W. P.
Bosman, R. de Gelder, R. Israel and J. M. M. Smits, Technical
Report of the Crystallography Laboratory, University of Nijmegen,
1994.
14 International Tables for X-Ray Crystallography, Kynoch Press,
Birmingham, 1974, vol. 4; J. A. Ibers and W. C. Hamilton, Acta
Crystallogr., 1964, 17, 781; International Tables for X-Ray
Crystallography, Kluwer, Boston, MA, 1992, vol. C.
8 P. Garrou, Chem. Rev., 1981, 81, 229.
9 C. K. Johnson, ORTEP II, Report ORNL-5138, Oak Ridge
National Laboratory, Oak Ridge, TN, 1976.
15 TEXSAN for Windows, Crystal Structure Analysis Package,
Molecular Structure Corporation, Houston, TX, 1997.
1936
J. Chem. Soc., Dalton Trans., 2000, 1931–1936