Synthesis and structure of a novel ruthenium hydrido bis(dihydrogen) complex with l,4,7-trimethyl-l,4,7-triazacyclononane ligand: A useful precursor for synthesis of heterometallic complexes

Article abstract of DOI:10.1021/om900692j

The ruthenium hydrido bis(dihydrogen) complex [Cn*RuH(H ₂)2][PF₆] (2-PF6; Cn* = 1,4,7-trimethyl-l,4,7- triazacyclononane) was synthesized by treatment of Cn*RuCl₃ with NaBH₄. Complex 2-PF₆ undergoes a H/D exchange between its hydrido ligands and CD₃OD, D₂, or THF-d_g. Treatment of 2-PF₆ with Cp*IrH₄ or Cp*OsH ₅ (Cp* = CsMe₅) affords the heterometallic dinuclear polyhydrido complexes [Cn*Ru(μ-H)₃IrCp*][PF ₆] (3-PF₆) and [Cn*Ru(μ-H) ₃OsHCp*][PF₆] (4-PF₆), respectively. Treatment of 3-PF₆ with triphenylphosphine affords the complex [Ru(PPh₃)(μ-η³:η¹-Cn*CH ₂ (μ-H)₂IrCp*][PF₆] (5-PF ₆), in which the triphenylphosphine is coordinated to the Ru atom as a terminal ligand and the C-H bond of the methyl group in the Cn* ligand is cleaved by the Ir atom. Reaction of 3-PF₆ with acetylene gives a bis(μ-vinyl) complex, [Cn*Ru(μ-o,π-CH=CH₂)IrH(μ-o, πCH=CH₂)Cp*][PF₆] (6-PF₆), in which one vinyl ligand is cr-bonded to the Ru atom and the other is -bonded to the Ir atom. The molecular structures of 2-PF₆, [Cn*Ru(μ-H) ₃Ir(C5Me4Et)][BPh₄] (3'-BPh4), 4-BPh₄,5- BPh₄, and 6-PF₆ were confirmed by -ray analyses, and the coordination modes of the hydrido ligands in 2-PF₆ were confirmed by density functional theory calculations.

Full text of DOI:10.1021/om900692j

Organometallics 2010, 29, 337–346 337
DOI: 10.1021/om900692j
Synthesis and Structure of a Novel Ruthenium Hydrido Bis(dihydrogen)
Complex with 1,4,7-Trimethyl-1,4,7-triazacyclononane Ligand: A Useful
Precursor for Synthesis of Heterometallic Complexes
Takanori Shima,† Kyo Namura, Hajime Kameo, Satoshi Kakuta, and Hiroharu Suzuki*
Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of
Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan. † Current address:
Organometallic Chemistry Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa,
Wako, Saitama 351-0198, Japan.
Received August 4, 2009
The ruthenium hydrido bis(dihydrogen) complex [Cn*RuH(H2)2][PF6] (2-PF6; Cn* = 1,4,7-tri-
methyl-1,4,7-triazacyclononane) was synthesized by treatment of Cn*RuCl3 with NaBH4. Complex
2-PF6 undergoes a H/D exchange between its hydrido ligands and CD3OD, D2, or THF-d8. Treatment
of 2-PF6 with Cp*IrH4 or Cp*OsH5 (Cp*=C5Me5) affords the heterometallic dinuclear polyhydrido
complexes [Cn*Ru(μ-H)3IrCp*][PF6] (3-PF6) and [Cn*Ru(μ-H)3OsHCp*][PF6] (4-PF6), respectively.
Treatment of 3-PF6 with triphenylphosphine affords the complex [Ru(PPh3)(μ-η3:η1-Cn*CH2)-
(μ-H)2IrCp*][PF6] (5-PF6), in which the triphenylphosphine is coordinated to the Ru atom as a
terminal ligand and the C-H bond of the methyl group in the Cn* ligand is cleaved by the Ir atom.
Reaction of 3-PF6 with acetylene gives a bis(μ-vinyl) complex, [Cn*Ru(μ-σ,π-CHdCH2)IrH(μ-σ,π-
CHdCH2)Cp*][PF6] (6-PF6), in which one vinyl ligand is σ-bonded to the Ru atom and the other is
σ-bonded to the Ir atom. The molecular structures of 2-PF6, [Cn*Ru(μ-H)3Ir(C5Me4Et)][BPh4]
(30-BPh4), 4-BPh4, 5-BPh4, and 6-PF6 were confirmed by X-ray analyses, and the coordination modes
of the hydrido ligands in 2-PF6 were confirmed by density functional theory calculations.
Introduction
However, all these heterometallic polyhydrido complexes
contain Cp* (C5Me5) groups as the ancillary ligands.
The reactivity of a heterometallic polynuclear complex is
strongly affected by the nature of the supporting ligands as
well as by the combination of metals that comprise the
complex. Taking our study on heterometallic polynuclear
complexes further, we have synthesized a novel hydrido
complex that has a 1,4,7-trimethyl-1,4,7-triazacyclononane
(Cn*) ligand,9 instead of a Cp* ligand, as a building block for
a novel heterometallic polyhydrido complex.
Cyclopentadienyl and 1,4,7-triazacyclononane derivatives
are useful ligands in organometallic chemistry. They are
coordinated to metals in a facial geometry as six-electron
donors. However, they differ in their π-accepting abilities,
with those of cyclopentadienyl compounds being stronger
than those of 1,4,7-triazacyclononane derivatives. There-
fore, substitution of a Cp* ligand by a Cn* ligand induces
considerable changes in the electronic environment around
the metal center.10
Heterometallic polynuclear complexes are of considerable
interest because of the promise of enhanced stoichiometric or
catalytic reactivity as a result of synergistic interactions
between metal centers with differing electronic properties.1
We recently reported on Cp*Ru-based heterometallic poly-
nuclear polyhydrido complexes containing combinations
such as Ru-Ir,2 Ru-Mo,3 Ru-W,3 Ru-Re,4 Ru-Os,5
Ru2-Ir,6 Ru2-Rh,6 Ru2-Os,7 Os2-Ru,7 Ru2-Re,4 Re2-
Ru,4 Ru2-W,8 and Ru2-Mo8 as precursors of active species
for heterometallic activation. Several appropriate examples
of site-selective coordination and activation through reac-
tions with organic substrates have been demonstrated.
*To whom correspondence should be addressed. E-mail: hiroharu@
n.cc.titech.ac.jp. Tel: (þ81)-3-5734-2148. Fax: (þ81)-3-5734-2623.
(1) For recent examples, see: Comprehensive Organometallic Chem-
istry III; Crabtree, R. H., Mingos, D. M. P., Eds.; Elsevier: Oxford, U.K.,
2007; Vol. 6, and references cited therein.
(2) (a) Shima, T.; Suzuki, H. Organometallics 2000, 19, 2420.
(b) Shima, T.; Suzuki, H. Organometallics 2005, 24, 1703.
(3) Shima, T.; Ito, J.; Suzuki, H. Organometallics 2001, 20, 10.
(4) Ito, J.; Shima, T.; Suzuki, H. Organometallics 2004, 23, 2447.
(5) (a) Shima, T.; Suzuki, H. Organometallics 2005, 24, 3939.
(b) Shima, T.; Ichikawa, T.; Suzuki, H. Organometallics 2007, 26, 6329.
(c) Kameo, H.; Nakajima, Y.; Suzuki, H. Angew. Chem., Int. Ed. 2008, 47,
10159.
Here we report the synthesis of the novel ruthenium penta-
hydrido complex [Cn*RuH(H2)2][PF6] (2-PF6),11 which is the
first example of a bis(dihydrogen) complex supported by a
Cn* ligand.12 Complex 2-PF6 exhibits a high reactivity toward
(9) Chaudhuri, P.; Wieghardt, K. Prog. Inorg. Chem. 1987, 35, 329.
(10) Cn*-ligated rhodium complexes show some different properties
compared with Cp*-ligated ones. See: (a) Wang, L.; Wang, C.; Bau, R.;
Flood, T. C. Organometallics 1996, 15, 491. (b) Wang, C.; Ziller, J. W.;
Flood, T. C. J. Am. Chem. Soc. 1995, 117, 1647. (c) Wang, L.; Lu, R. S.;
Bau, R.; Flood, T. C. J. Am. Chem. Soc. 1993, 115, 6999. (d) Wang, L.;
Flood, T. C. J. Am. Chem. Soc. 1992, 114, 3169.
(6) Shima, T.; Sugimura, Y.; Suzuki, H. Organometallics 2009, 28,
871.
(7) Kameo, H.; Shima, T.; Nakajima, Y.; Suzuki, H. Organometallics
2009, 28, 2535.
(8) Ito, J.; Shima, T.; Suzuki, H. Organometallics 2006, 25, 1333.
r
2009 American Chemical Society
Published on Web 12/16/2009
pubs.acs.org/Organometallics

338 Organometallics, Vol. 29, No. 2, 2010
Shima et al.
the Cp*-ligated polyhydrides Cp*IrH4 and Cp*OsH5 to give
the heterometallic dinuclear polyhydrido complexes [Cn*Ru-
(μ-H)3IrCp*][PF6] (3-PF6) and [Cn*Ru(μ-H)3OsHCp*][PF6]
(4-PF6), respectively, both of which contain a Cp* moiety and
a Cn* moiety as ancillary ligands within their molecules. The
site selectivity of the Ru and Ir centers in reactions of 3-PF6
with triphenylphosphine and acetylene was examined, and the
reactivities of the complexes were compared with those of a
Cp*Ru-based heterometallic complex.
Results and Discussion
Synthesis of the Ruthenium Hydrido Bis(dihydrogen) Com-
plex [Cn*RuH(H2)2][PF6] (2-PF6). There are no previous
reports of ruthenium complexes that contain only Cn* and
hydrido ligands, although Wieghardt et al.13 have reported
syntheses of dinuclear polyhydrido complexes of rhodium
and of iron: namely, anti-[Cn*Rh(H)(μ-H)]22þ and [Cn*Fe-
(μ-H)3FeCn*]þ, respectively. We therefore attempted to synthe-
size a novel Cn*Ru polyhydrido complex that could serve as a
building block for new types of polyhydrido cluster complexes.
The reaction of Cn*RuCl3 (1)11o with NaBH4 in ethanol
afforded a pale yellow solution. On addition of NH4PF6 to
the filtered reaction solution, the pentahydrido complex
[Cn*RuH(H2)2][PF6] (2-PF6) precipitated (eq 1). The tetra-
phenylborate salt (2-BPh4) and the tetrafluoroborate salt
(2-BF4) were obtained quantitatively by adding NaBPh4 or
Figure 1. Density functional theþory (DFT) calculation for the
structure of [Cn*RuH(H2)2]þ (2 ). Selected bond lengths (A):
˚
Ru1-N1, 2.1688; Ru1-N2, 2.1670; Ru1-N3, 2.2626; Ru1-
H1, 1.5943, Ru1-H2, 1.6443; Ru1-H3, 1.6678; Ru1-H4,
1.6433; Ru1-H5, 1.6673; H1-H2, 1.8348; H1-H4, 1.8300;
H2-H3, 0.9360; H3-H5, 2.2111; H4-H5, 0.9375.
observed for [Cn*RuH(CO)(PPh3)][PF6] (δ -13.75).11j The
hydrido signal in 2-PF6 remained fairly constant in the tem-
perature range þ23 to -115 °C; the longitudinal relaxation
time (T1, THF-d8/toluene-d8=5/1) of the hydrido ligands was
also evaluated in the same temperature range. The minimum
value observed was 18 ms at -115 °C, which suggested that
2-PF6 contains a contribution from a dihydrogen complex.
Density functional theory (DFT) calculations at the
B3PW91 level indicate that the five hydride ligands in 2-
PF6 consist of two dihydrogen ligands and one hydrido
ligand (Figure 1).14 The geometry around the ruthenium
atom is octahedral, and the Ru-N distance trans to the
HBF4 OMe2, respectively, to an ethanolic solution of 2-PF6.
3
Complex 2-PF6 is fairly stable in the solid state, but the color
of a solution of 2-PF6 changed instantly to red-purple in the
presence of even a trace amount of air.
˚
hydrido ligand (Ru1-N3, 2.263 A) is longer than the dis-
tances trans to the dihydrogen ligands (Ru1-N1, Ru1-N2,
˚
2.168 A (av)). This elongation of the Ru-N bond is due to
the stronger trans influence of the hydrido ligand in compar-
ison with that of the η2-hydrogen ligands.
The equality of the chemical shifts for the hydrido and the
The 1H NMR spectrum of 2-PF6 in acetone-d6 showed a
sharp “hydrido” signal at δ -12.53 (5H) and one set of
signals for the Cn* ligands in the appropriate ratio. The
chemical shift of the “hydrido” ligand was comparable to that
1
η2-H2 ligands in the H NMR spectra over the temperature
rangeþ23to-115 °Cstrongly suggests the presenceof a rapid
site-exchange process among these ligands (Scheme 1). The
energy barriers for the η2-H2-hydrido site exchange and for
rotation of η2-H2 along the Ru-H2 axis were evaluated to be
1.0 and 2.9 kcal/mol, respectively, by DFT calculations. These
values are also consistent with the experimental observations.
Complex 2-PF6 readily underwent H/D exchange reaction
with methanol-d4 at ambient temperature, resulting in con-
secutive formation of the isotopomers [Cn*RuH5-nDn][PF6]
(2-dn). The time course of the H/D exchange reaction with
CD3OD was monitored by means of 1H NMR spectroscopy
(Figure 2); the isotopomers [Cn*RuH4D][PF6] (2-d1),
[Cn*RuH3D2][PF6] (2-d2), and [Cn*RuH2D3][PF6] (2-d3)
appeared consecutively at δ -12.58 (t, JHD =5.6 Hz), -12.60
(quintet, JHD =5.2 Hz), and -12.62 (septet, JHD =5.2 Hz).
The coupling constants JHD are basically similar to those
observed in the hydrido tris(3,5-dimethylpyrazolyl) borate com-
plex Tp*RuH(H2)2 (JHD=5.4 Hz), in which two dihydrogen
molecules are coordinated.15 Although H/D exchange with
(11) For recent examples of a Cn*-ligated ruthenium complex, see:
(a) Gott, A. L.; McGowan, P. C.; Podesta, T. J. Dalton Trans. 2008,
3729. (b) Yip, W. P.; Ho, C. M.; Zhu, N.; Lau, T. C.; Che, C. M. Chem. Asian
J. 2008, 3, 70. (c) Yip, W. P.; Yu, W. Y.; Zhu, N.; Che, C. M. J. Am. Chem.
Soc. 2005, 127, 14239. (d) Cameron, B. R.; Darkes, M. C.; Baird, I. R.;
Skerlj, R. T.; Santucci, Z. L.; Fricker, S. P. Inorg. Chem. 2003, 42, 4102.
(e) Cheung, W. H.; Yu, W. Y.; Yip, W. P.; Zhu, N. Y.; Che, C. M. J. Org.
Chem. 2002, 67, 7716. (f) Che, C. M.; Yu, W. Y.; Chan, P. M.; Cheng, W. C.;
Peng, S. M.; Lau, K. C.; Li, W. K. J. Am. Chem. Soc. 2000, 122, 11380.
(g) Au, S. M.; Zhang, S. B.; Fung, W. H.; Yu, W. Y.; Che, C. M.; Cheung,
K. K. Chem. Commun. 1998, 2677. (h) Ng, S. M.; Fang, Y. Q.; Lau, C. P.;
Wong, W. T.; Jia, G. Organometallics 1998, 17, 2052. (i) Yang, S. M.; Chan,
M. C. W.; Cheung, K. K.; Che, C. M.; Peng, S. M. Organometallics 1997, 16,
2819. (j) Yang, S. M.; Cheng, W. C.; Peng, S. M.; Cheung, K. K.; Che, C. M.
J. Chem. Soc., Dalton Trans. 1995, 2955. (k) Yang, S. M.; Cheng, W. C.;
Cheung, K. K.; Che, C. M.; Peng, S. M. J. Chem. Soc., Dalton Trans. 1995,
227. (l) Cheng, W. C.; Yu, W. Y.; Cheung, K. K.; Che, C. M. J. Chem. Soc.,
Dalton Trans. 1994, 1063. (m) Cheng, W. C.; Yu, W. Y.; Cheung, K. K.; Che,
C. M. J. Chem. Soc., Dalton Trans. 1994, 57. (n) Hotzelmann, R.;
€
Wieghardt, K.; Florke, U.; Haupt, H.-J. Angew. Chem., Int. Ed. Engl.
1990, 29, 645. (o) Neubold, P.; Wieghardt, K.; Nuber, B.; Weiss, J. Inorg.
Chem. 1989, 28, 459.
(12) A bis(2-aminoethyl)amine-ligated osmium bis(dihydrogen) com-
(14) Details are given in the Supporting Information.
(15) The number of coordinated dihydrogen molecules can also be
estimated from the JHD value. See: Moreno, B.; Sabo-Etienne, S.;
Chaudret, B.; Rodriguez, A.; Jalon, F.; Trofimenko, S. J. Am. Chem.
Soc. 1995, 117, 7441.
ꢀ
plex has recently been reported; see: Baya, M.; Esteruelas, A.; Olivan, M.;
~
Onate, E. Inorg. Chem. 2009, 48, 2677.
(13) Hanke, D.; Wieghardt, K.; Nuber, B.; Lu, R. S.; Mcmullan,
R. K.; Koetzle, T. F.; Bau, R. Inorg. Chem. 1993, 32, 4300.

Article
Organometallics, Vol. 29, No. 2, 2010 339
Figure 2. H/D exchange reaction of 2-PF6 showing hydride resonances (room temperature, THF-d8): (a) initial spectrum, 2-PF6;
(b) after 15 min with CD3OD, a mixture of 2-PF6, 2-d1, and 2-d2; (c) after 1 h with CD3OD; (d) after 9 h with CD3OD, a mixture of 2-d2
and 2-d3.
Scheme 1. Site-Exchange Process of Hydrido Ligands in 2-PF6
THF-d8 took place, the difference in the signal intensities
between the 2-PF6-D2/THF-d8 and 2-PF6/THF-d8 systems
evidently showed that partial deuteration proceeded slowly
between 2-PF6 and D2 at atmospheric pressure (see the Sup-
porting Information; SFigure 1). Note that the monodeuterated
complex 2-d1 was formed as an initial product. This probably
suggests that the H/D exchange reaction proceeds by a σ-bond
metathesis between the D-D bond and the Ru-H bond.
Alternatively, H/D exchange through heterolytic D-D bond
cleavage is also possible.
To the best of our knowledge, complex 2-PF6 is the first
reported example of a ruthenium bis(dihydrogen) complex
containing a Cn* ligand. However, several nonclassical
transition-metal dihydrogen complexes have been synthe-
sized by the reaction of metal halides with NaBH4, LiAlH4,
or NaH.16 Furthermore, related ruthenium bis(dihydrogen)
complexes supported by bulky phosphine ligands17 or
hydridotris(pyrazolyl) borate ligands15 have also been re-
ported.
Synthesis of the Heterometallic Dinuclear Polyhydrido
Complexes [Cn*Ru(μ-H)3MHnCp*][PF6] (M=Ir, n=0 (3-
PF6); M = Os, n = 1 (4-PF6)). We have previously shown
that dehydrogenative coupling between two metal hydride
fragments is an achievable and practical method for the
synthesis of heterometallic polyhydrido complexes.4,6,7
However, there are no reports of any heterometallic di-
nuclear polyhydrido complexes that have both Cp* and
Cn* groups within a molecule.18 Replacement of one Cp*
ligand by a Cn* ligand changes the magnitude and direction
of the polarization between the metal centers. The electron
The molecular structure of 2-PF6 was determined by X-ray
diffraction. The ORTEP drawing is shown in Figure 3, with
some relevant bond lengths and angles. Although the hydrido
and coordinated dihydrogen ligands were not located, the
˚
presence of two short Ru-N bonds (2.1395(14), 2.1521(16) A)
˚
and one long Ru-N bond (2.2082(14) A) corresponded
closely with the results of DFT calculations. We therefore
conclude that the two dihydrogen molecules are coordinated
trans to nitrogen with two short Ru-N bonds and that the
single hydrido ligand is coordinated trans to nitrogen with a
long Ru-N bond.
(17) (a) Grellier, M.; Vendier, L.; Chaudret, B.; Albinati, A.; Rizzato,
S.; Mason, S.; Sabo-Etienne, S. J. Am. Chem. Soc. 2005, 127, 17592.
(b) Abdur-Rashid, K.; Gusev, D. G.; Lough, A. J.; Morris, R. H. Organo-
metallics 2000, 19, 1652. (c) Borowski, A. F.; Donnadieu, B.; Daran, J.-C.;
Sabo-Etienne, S.; Chaudret, B. Chem. Commun. (Cambridge, U.K.) 2000,
543.
(16) (a) Bucher, U. E.; Lengweiler, T.; Nanz, D.; Von Philipsborn,
W.; Venanzi, L. M. Angew. Chem., Int. Ed. Engl. 1990, 29, 548. (b) Aresta,
M.; Giannoccaro, P.; Rossi, M.; Sacco, A. Inorg. Chim. Acta 1971, 5, 115.
(c) Baudry, D.; Ephritikhine, M.; Felkin, H. J. Organomet. Chem. 1982, 224,
363. (d) Jia, G.; Meek, D. W. J. Am. Chem. Soc. 1989, 111, 757.
(18) For examples of Cn*-ligated heterobimetallics, see ref 11n.

340 Organometallics, Vol. 29, No. 2, 2010
Shima et al.
Figure 3. ORTEP drawing of 2-PF6 with thermal ellipsoids at
˚
the 30% probability level. Selected bond lengths (A) and angles
(deg): Ru1-N1, 2.1395(14); Ru1-N2, 2.1521(16); Ru1-N3,
2.2082(14); N1-Ru1-N2, 82.43(5); N1-Ru1-N3, 81.70(5);
N2-Ru1-N3, 81.07(5).
density of the metal center ligated by Cn* increases as a result
of the high σ-donating ability and low π-accepting ability
of Cn*. We successfully synthesized novel heterometallic
dinuclear complexes [Cn*Ru(μ-H)3MHnCp*][PF6] (M =
Ir, n = 0; M = Os, n = 1) through dehydrogenative coupling
of 2-PF6 with Cp*MH4þn (M = Ir, n = 0; M=Os, n = 1).
19
The reaction of 2-PF6 with Cp*IrH4 in methanol at
60 °C resulted in the exclusive formation of the heterometallic
dinuclear trihydrido complex [Cn*Ru(μ-H)3IrCp*][PF6]
(3-PF6), which was isolated as a reddish purple solid in 92%
yield (eq 2). The (η5-C5Me4Et)Ir analogue [Cn*Ru(μ-H)3-
Ir(η5-C5Me4Et)][PF6] (30-PF6) was also synthesized in a similar
manner by using [(η5-C5Me4Et)IrH4] as the starting material.
Figure 4. Variable-temperature 400-MHz 1H NMR spectra
(acetone-d6) of [Cn*Ru(μ-H)3OsHCp*][PF6] (4-PF6): (a) Cn*
resonances; (b) hydride resonances.
lent at δ 3.43 (9H); furthermore, the signals of the hydride
ligands were observed to be equivalent at δ -19.26 (4H).
With a decrease in the temperature, both the signals broa-
dened and decoalesced at between -60 and -70 °C. The
signals narrowed gradually as the temperature was de-
creased. The hydrido signal at δ -20.60 split further into
two singlets. At -90 °C, two separated methyl signals with
an intensity ratio of 2:1 were observed at δ 3.44 (6H) and 3.09
(3H), respectively, and three hydrido signals with an inten-
sity ratio of 2:1:1 were observed at -17.95 (2H), -20.54
(1H), and -20.62 (1H), respectively. The change in the
signals for the Cn* and the hydrido ligands shows the
existence of an exchange of coordination sites among the
four hydrido ligands (Scheme 2); this is completely consistent
with the X-ray structure (see below), which has a plane of
pseudosymmetry comprising the terminal hydride, one of the
bridging hydrides, one of the methyl groups in the Cn*
ligand, and the two metal atoms.
Complex 3-PF6 was identified on the basis of its 1H NMR
spectrum, which exhibited three singlet signals at δ 3.49 (9H),
2.11 (15H), and -20.75 (3H); these were assigned to the three
methyl groups in the Cn* ligand, the Cp* group, and the
bridging hydride ligands, respectively.
The Ru-Os analogue [Cn*Ru(μ-H)3OsHCp*][PF6] (4-PF6)
5a,20
was similarly prepared by using Cp*OsH5
as the starting
material. Treatment of 2-PF6 with Cp*OsH5 in methanol at
70 °C for 8 h afforded 4-PF6 as a brown solid in 94% yield
(eq 3). The IR spectrum of 4-PF6 showed a peak corresponding
to the Os-Ht stretching vibration at 2088 cm-1
.
X-ray diffraction studies on 30-BPh4 and 4-BPh4 clearly
establish a dinuclear structure bridged by three hydride
groups. ORTEP drawings of the cationic parts of the mole-
cules are shown in Figure 5, along with some of the relevant
bond distances and angles. The Ru-Ir and Ru-Os distances
The variable-temperature 1H NMR spectra of 4-PF6,
shown in Figure 4, clearly establishes the fluxionality of the
Cn* ligand and the hydrides. At room temperature, the
methyl signals of the Cn* group were observed to be equiva-
˚
of 2.4361(6) and 2.4110(3) A, respectively, are slightly short-
2
˚
er than those in [(C5Me4Et)Ru(μ-H)3IrCp*] (2.4858(4) A)
5a
˚
or in [(C5Me4Et)Ru(μ-H)4OsCp*] (2.4663(5) A). The co-
ordination geometries at Ru and Ir in 30-BPh4 are described
as octahedral and a three-legged stool-like arrangement,
respectively. One hydrogen ligand in 4-BPh4 is bound to
(19) Gilbert, T. M.; Hollander, F. J.; Bergman, R. G. J. Am. Chem.
Soc. 1985, 107, 3508.
(20) Gross, C. L.; Girolami, G. S. Organometallics 2007, 26, 160.

Article
Organometallics, Vol. 29, No. 2, 2010 341
Scheme 2. Site-Exchange Process among the Four Hydrido
Ligands in 4þ
the Os atom as a terminal hydride. The geometries at Ru and
Os are octahedral and pseudotrigonal bipyramidal, respec-
tively; the H1 and H4 ligands occupy the axial positions, and
the centroid of the Cp* ligand (CP) and the H2 and H3
ligands all lie on the equatorial plane. The ruthenium atom is
sterically shielded by the three methyl groups of the Cn*
ligand, and a substrate will be hindered from accessing to the
ruthenium center.
To evaluate the effects of introducing the Cn* ligand, we
performed DFT calculations at the B3PW91 level for 3þ, 4þ,
[Cp*Ru(μ-H)3IrCp*], and [Cp*Ru(μ-H)4OsCp*].21 The cal-
culation reproduced well the structures of the four com-
plexes. Natural population analysis22 indicated that the
direction of polarization between ruthenium and iridium is
reversed (3þ, Ru -0.396, Ir -0.248; [Cp*Ru(μ-H)3IrCp*],
Ru -0.324, Ir -0.449) and that the magnitude of polariza-
tion between ruthenium and osmium is significantly de-
creased by substitution of a Cn* ligand for a Cp* ligand
on ruthenium (4þ, Ru -0.347, Os -0.636; [Cp*Ru(μ-H)4-
OsCp*], Ru -0.343, Os -0.948).
Figure 5. ORTEP drawings of (a) 30-BPh4 and (b) 4-BPh4 with
thermal ellipsoids at the 30% probability level. The anionic
moiety (BPh4-) and solvent molecule (acetone) are omitted for
clarity. Some methylene carbons in 4-BPh4 were diso0rdered.
˚
Selected bond distances (A) and angles (deg) for 3 -BPh4:
Ru1-Ir1, 2.4361(6); Ir1-CP, 1.799; Ru1-N1, 2.125(4);
Ru1-N2, 2.140(4); Ru1-N3, 2.123(4); Cn*centroid-Ru1-Ir1,
˚
177.3; Ru1-Ir1-CP, 176.2. Selected bond distances (A) and
angles (deg) for 4-BPh4: Ru1-Os1, 2.4110(3); Os1-CP, 1.848;
Ru1-N1, 2.131(3); Ru1-N2, 2.123(4); Ru1-N3, 2.132(4);
Cn*centroid-Ru1-Os1, 178.6; Ru1-Os1-CP, 159.5 (CP =
Cp* centroid).
Treatment of 3-PF6 with 2 equiv of triphenylphosphine in
toluene at 60 °C led to exclusive formation of 5-PF6 in a
quantitative yield. In this compound, the phosphine is
coordinated to the Ru atom as a terminal ligand, and the
C-H bond of the methyl group in the Cn* ligand is cleaved
by the Ir atom (eq 4). The 31P NMR spectrum of 5-PF6
showed a resonance signal for the terminal phosphine ligand
at δ 72.8, which is comparable to that observed for
[Cp*Ru(PPh3)H3] (δ 79.3).23 In the 1H NMR spectrum,
the hydrido signal appeared at δ -25.51 (2H) as a doublet
(JHP =13.6 Hz) due to coupling with the 31P nucleus. The
methylene hydrogens of the Ir-CH2- group were observed
at δ 4.52 (2H) as a singlet. In the 13C NMR spectrum, the
methylene carbon of the Ir-CH2- group was observed at
δ 70.2, which is shifted downfield compared with that of the
other N-CH3 group (δ 59.5).
The DFT calculations also showed that substitution of
Cn* for Cp* resulted in a change in the metal-hydride
distances. The hydrido ligands occupy positions almost
˚
equidistant from both metal centers (dRu-H(av)=1.8045 A,
þ
þ
˚
dIr-H(av)=1.7868 A) in [Cn*Ru(μ-H)3IrCp*] (3 ), whereas
the hydride ligands are located nearer to the iridium atom
than to the ruthenium atom in [Cp*Ru(μ-H)3IrCp*]
˚
˚
(dRu-H(av) = 1.8718 A, dIr-H(av) = 1.7101 A).
Reaction with Triphenylphosphine. The electronic situation
around the metal centers should crucially affect the reactivity
of the cluster. The (Cn*,Cp*)-ligated heterometallic dinuc-
lear polyhydrido complexes should, therefore, exhibit a
reactivity different from that of the (Cp*,Cp*)-ligated com-
plexes. We have previously demonstrated that the reaction of
the (Cp*,Cp*)-ligated Ru-Ir trihydrido complex [Cp*Ru-
(μ-H)3IrCp*] with triphenylphosphine gives the phosphido
complex [Cp*Ru(μ-PPh2)(μ-H)(μ-η1:η2-C6H5)IrCp*] as a
result of site-selective coordination of triphenylphosphine
at the Ru center and subsequent P-C bond cleavage of
triphenylphosphine at the Ir center.2b
Figure 6 shows the structure of 5-BPh4, in which a
triphenylphosphine molecule is coordinated to the Ru atom,
(21) For details see the Supporting Information.
(22) Reed, A. E.; Weinstock, R. B.; Weinhold, F. J. Chem. Phys.
1985, 83, 735.
(23) Suzuki, H.; Lee, D. H.; Oshima, N.; Moro-oka, Y. Organo-
metallics 1987, 6, 1569.

342 Organometallics, Vol. 29, No. 2, 2010
Shima et al.
Figure 7. ORTEP drawing of the cationic parts of 6-PF6 with
thermal ellipsoids at the 30% probability level. The anionic
moiety (PF6-) is omitted for clarity. Cp* carbons were disor-
˚
dered (50:50). Selected bond lengths (A) and angles (deg):
Figure 6. ORTEP drawing of the cationic parts of 5-BPh4 with
thermal ellipsoids at the 30% probability level. The anionic
˚
moiety (BPh4 ) is omitted for clarity. Selected bond lengths (A)
and angles (deg): Ru1-Ir1, 2.6459(4); Ir1-C11, 2.058(5);
Ru1-P1, 2.2990(12); Ru1-N1, 2.114(4); Ru1-N2, 2.203(4);
Ru1-N3, 2.172(4); Ir1-CP, 1.837; P1-Ru1-N1, 173.98(12);
P1-Ru1-N2, 103.00(12); P1-Ru1-N3, 103.68(12); P1-
Ru1-Ir1, 99.40(3); Ir1-C11-N1, 109.5(3); Ru1-N1-C11,
101.4(3); Ru1-Ir1-CP, 159.7 (CP = Cp* centroid).
Ru1-Ir1, 2.7152(5); Ir1-C1, 2.029(6); Ir1-C3, 2.155(5);
Ir1-C4, 2.192(7); Ru1-C1, 2.157(5); Ru1-C2, 2.189(6); Ru1-
C3, 2.032(6); C1-C2, 1.407(9); C3-C4, 1.431(8); Ru1-N1,
2.245(5); Ru1-N2, 2.191(5); Ru1-N3, 2.183(5); Ir1-CP,
1.872 (CP = Cp* centroid).
-
110.2 (d, JCH = 151.5 Hz) and 56.6 (t, JCH = 149.8 Hz). The
first sets of 1H and 13C NMR spectral signals were assigned
to a vinyl ligand σ-bonded to Ru, and the second sets were
assigned to one σ-bonded to Ir. The signal for the R-carbon
of the Ir-σ-bonded vinyl ligand (δ 110.2) shifted significantly
upfield compared with that of the Ru-σ-bonded vinyl ligand
(δ 139.2). This tendency is also observed in the dinuclear
bis(μ-vinyl) complexes [Cp*Ru(μ-σ,π-CHdCH2)2IrHCp*]
(δ 141.8)2a and [Cp*Ru(η2-CH2dCH2)(μ-σ,π-CHdCH2)2-
RuCp*] (δ 188.5).24
and one of the methyl groups in the Cn* ligand is σ-bonded
to the Ir atom. Although one hydride ligand is missing in the
structure of 5-BPh4, the geometry at Ru is octahedral with P1
and N1 occupying the axial positions and H1, N2, and N3
lying on the equatorial plane. The Ru1-P1 bond length
˚
(2.2990(12) A) is comparable to that in the terminally
coordinated phosphine complex [Cp*Ru(PPh3)H3] (Ru-P,
23
˚
˚
2.252(1) A). The Ir1-C11 bond length (2.058(5) A) is also
consistent with that of an Ir-C σ-bond. The Ru1-Ir1 bond
length (2.6459(4) A) is significantly longer than that ob-
˚
0
˚
served in 3 -BPh4 (2.4361(6) A).
The formation of 5-PF6 probably proceeds through an
associative mechanism in which the triphenylphosphine
moiety coordinates initially to the Ru center, forcing the
methyl group attached to the trans nitrogen atom to ap-
proach the Ir atom. As a result, the C-H bond of the methyl
group becomes coordinated to the Ir center. Subsequent
liberation of dihydrogen and cleavage of the C-H bond at
the Ir center generates 5-PF6. No cleavage of the P-Ph bond
of triphenylphosphine at the Ir center occurs, probably as a
result of the stable octahedral geometry around the Ru
center in 5-PF6.
The structure of 6-PF6 was unequivocally established by
means of X-ray diffraction (Figure 7). This ORTEP drawing
clearly shows that one of the two vinyl ligands of 6-PF6 is
σ-bonded to the Ru and that the other is σ-bonded to the Ir.
The Cn* and Cp* ligands are mutually cis with respect to the
Ru-Ir vector. The Ir1-C1 and the Ru1-C3 bond lengths of
˚
2.029(6) and 2.032(6) A, respectively, are consistent with
Ir-C and Ru-C σ-bonds. The Ru1-C1,C2 and Ir1-C3,C4
˚
bond lengths of 2.155(5)-2.192(7) A lie well within the range
Reaction with Acetylene. Next, we investigated the reaction
of 3-PF6 with unsaturated hydrocarbons by using acetylene.
Complex 3-PF6 reacted smoothly with acetylene (1 atm)
at room temperature to produce a bis(μ-vinyl) complex,
[Cn*Ru(μ-σ,π-CHdCH2)IrH(μ-σ,π-CHdCH2)Cp*][PF6]
(6-PF6), in 85% yield. In this compound, one vinyl ligand
is σ-bonded to the Ru atom and the other is σ-bonded to the
Ir atom (eq 5). By following this reaction by means of
for the lengths of bonds between Ru (or Ir) and π-bonded
˚
carbon atoms. The C3-C4 distance (1.431(8) A) is slightly
˚
longer than the C1-C2 distance (1.407(9) A). The C-C
bond length of the π-coordinated vinyl group may reflect the
strength of back-donation from the metal atom to the vinyl
group, and the longer C3-C4 distance of one vinyl group
(Ru-C3dC4) in comparison with the C1-C2 distance of the
other vinyl group (Ir-C1dC2) strongly suggests that back-
donation from Ir to its attached vinyl group is stronger than
that from Ru to its attached vinyl group.
1
low-temperature H NMR spectroscopy, we identified un-
characterized intermediates that were present in yields of less
1
than 20%. In the H NMR spectra of 6-PF6, one set of
The reaction of [Cp*Ru(μ-H)3IrCp*] with acetylene gives
different products from that obtained with 3-PF6. The reac-
tion of [Cp*Ru(μ-H)3IrCp*] with acetylene initially affords a
bis(μ-vinyl) complex, [Cp*Ru(μ-σ,π-CHdCH2)2IrHCp*],
in which both vinyl ligands are σ-bonded to the Ru atom.
signals assignable to the two vinyl groups was observed at
δ 6.31 (dd, J = 10.8, 8.0 Hz), 3.36 (d, J = 8.0 Hz), and
2.24 (d, J = 10.8 Hz), and another set was observed at δ 5.61
(ddd, J = 11.2, 8.4, 5.8 Hz), 1.83 (d, J = 8.4 Hz), and 1.43
(d, J = 11.2 Hz). The 13C signals for one of the two vinyl
groups appeared at δ 139.2 (d, JCH = 137.8 Hz) and 58.1
(t, JCH = 149.9 Hz), and those for the other appeared at δ
(24) Suzuki, H.; Omori, H.; Lee, D. H.; Yoshida, Y.; Fukushima, M.;
Tanaka, M.; Moro-oka, Y. Organometallics 1994, 13, 1129.

Article
Organometallics, Vol. 29, No. 2, 2010 343
Scheme 3. Reaction of [Cp*Ru(μ-H)3IrCp*] with Acetylene
This complex is stable at -10 °C but isomerizes readily at
room temperature to give a μ-vinyl-μ-ethylidene complex,
[Cp*Ru(μ-σ,π-CHdCH2)(μ-CHCH3)IrCp*], in which a vi-
nyl ligand is σ-bonded to the Ru atom (Scheme 3).25
The difference in the reaction modes toward acetylene be-
tween 3-PF6 and [Cp*Ru(μ-H)3IrCp*] is definitely due to
differences in the electronic and steric situation around the metal
centers that are induced by changing the ligand from Cp* to Cn*.
(μ-CHCH3)IrCp*]. Further studies on the reactivities of
these new heterometallic dinuclear polyhydrido complexes
and the syntheses of a new series of heterometallic complexes
from 2-PF6 are now in progress; the results will be reported in
due course.
Experimental Section
General Procedures. All manipulations were carried out
under an argon atmosphere with use of standard Schlenk
techniques. Toluene and THF were distilled from sodium
benzophenone ketyl prior to use. Pentane was dried over P2O5
and distilled prior to use. Methanol was dried over Mg(OMe)2
and distilled prior to use. Cn*RuCl311o (Cn* = 1,4,7-trimethyl-
1,4,7-triazacyclononane), Cp*IrH4,19 and Cp*OsH55a,20 (Cp*=
η5-C5Me5) were prepared according to previously published
methods. Other reagents were used as received. IR spectra
were recorded using a Nicolet Avatar 360 FT-IR and a Jasco
FT/IR-5000 spectrometer. 1H and 13C NMR spectra were
recorded using JEOL-GSX-500, Varian Gemini-300, and
INOVA-400 Fourier transform spectrometers with tetramethyl-
silane as an internal standard. 31P NMR spectra were recorded
using INOVA-400 Fourier transform spectrometers with 85%
H3PO4 as the external standard. Elemental analyses were re-
corded on a Perkin-Elmer 2400II.
[Cn*RuH(H2)2][PF6] (2-PF6). A slurry of Cn*RuCl3 (458 mg,
1.21 mmol) and NaBH4 (240 mg, 6.33 mmol) in ethanol (20 mL)
was stirred for 2 h at room temperature. The solution turned
pale yellow. The solution was passed through short columns
packed with Celite. An excess amount of NH4PF6 was added to
the filtrate, which afforded white precipitates. Washing the
precipitates with ethanol afforded 2-PF6 (461 mg, 1.09 mmol,
90%) as a white solid. Tetraphenylborate salt (2-BPh4) or
tetrafluoroborate salt (2-BF4) was obtained quantitatively by
adding 1.2 equiv of NaBPh4 at room temperature or an
Conclusion
The electronic states of the metal atoms in a cluster complex
can be tuned over a broad range by using a wide variety of
electronically different types of auxiliary ligands. Substituted
cyclopentadienyl ligands, which have been used for the synth-
eses of polyhydrido clusters, are basically π-accepting ligands,
although C5Me5 groups exhibit some electron-releasing char-
acter owing to the presence of the methyl substituents on the
C5 ring. Here, we attempted to synthesize a heterometallic
complex in which each metal was substituted with an electro-
nically different auxiliary ligand (Cp* and Cn*).
As a building block for the heterometallic mixed-ligand
complexes, we synthesized the first 1,4,7-trimethyl-1,4,7-
triazacyclononane (Cn*)-ligated ruthenium monohydrido
bis(dihydrogen) complex, [Cn*RuH(H2)2][PF6] (2-PF6), by
treatment of Cn*RuCl3 with NaBH4. The X-ray structure of
2-PF6 was supported by DFT calculations. Complex 2-PF6
underwent H/D exchange with methanol-d4 at ambient
temperature. Furthermore, a H/D exchange reaction be-
tween 2-PF6 and D2 raised the possibility of a heterolytic
cleavage of the D-D bond.
The reactions of 2-PF6 with the Cp*-ligated polyhydrido
complexes Cp*IrH4 and Cp*OsH5 readily gave the correspond-
ing heterometallic dinuclear polyhydrido complexes [Cn*Ru-
(μ-H)3IrCp*][PF6] (3-PF6) and [Cn*Ru(μ-H)3OsHCp*][PF6]
(4-PF6), respectively, as a result of the intermolecular dehydro-
genation reaction. The ease of formation of complexes 3-PF6
and 4-PF6 in this reaction suggested that 2-PF6 can serve as a
useful precursor (or a building block) for the synthesis of
heterometallic dinuclear polyhydrido complexes containing
Cn* and Cp* groups as ancillary ligands. The (Cn*,Cp*)-
ligated complex 3-PF6 exhibited reactivities that were definitely
different from those of the (Cp*,Cp*)-ligated complex [Cp*Ru-
(μ-H)3IrCp*]. Whereas the reaction of [Cp*Ru(μ-H)3IrCp*]
with triphenylphosphine affords the phosphido complex
[Cp*Ru(μ-PPh2)(μ-H)(μ-η1:η2-C6H5)IrCp*] through P-C
bond cleavage, the reaction of 3-PF6 with triphenylpho-
sphine gives the phosphine complex 5-PF6 through C-H
bond cleavage of the methyl group in the Cn* ligand. Treat-
ment of 3-PF6 with acetylene provided the bis(μ-vinyl)
complex 6-PF6, in which one vinyl ligand was σ-bonded to
the Ru and the other was σ-bonded to the Ir, whereas
the reaction of [Cp*Ru(μ-H)3IrCp*] with acetylene gave
the μ-vinyl-μ-ethylidene complex [Cp*Ru(μ-σ,π-CHdCH2)-
excess amount of HBF4 OMe2 at 0 °C to an ethanol solution
3
of 2-PF6.
Data for 2-PF6 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 3.35 (s, 9H, NCH3), 3.29-3.33 (m, 6H,
-NCHH-HHCN-), 3.20-3.27 (m, 6H, -NCHH-HHCN-),
-12.53 (s, 5H, Ru-H). T1 (-40 °C, CD3CN): 220(2) ms. T1
(THF-d8/toluene-d8 = 5/1): 30 (-95 °C), 25 (-100 °C), 24
(-105 °C), 20 (-110 °C), 18 (-115 °C) ms. 13C NMR (100
MHz, acetone-d6, room temperature): δ 61.3 (t, JCH = 139.2 Hz,
NCH2), 59.7 (q, JCH =139.5 Hz, NCH3). IR (ATR): 1956
(νRu-H) cm-1
.
Data for 2-BPh4 are as follows. 1H NMR (400 MHz, CD3CN,
room temperature): δ 7.27 (br, 8H, o-Ph), 7.00 (t, JHH = 7.6 Hz,
8H, m-Ph), 6.85 (t, JHH = 7.6 Hz, 4H, p-Ph), 3.21 (s, 9H,
NCH3), 3.08-3.16 (m, 6H, -NCHH-HHCN-), 2.91-2.99
(m, 6H, -NCHH-HHCN-), -12.67 (s, 5H, Ru-H). 13C
NMR (100 MHz, CD3CN, room temperature): δ 164.8 (q,
JCB = 47.0 Hz, ipso-Ph), 136.7 (dt, JCH = 157.9, 7.6 Hz, m-Ph),
126.6 (d, JCH = 153.3 Hz, o-Ph), 122.8 (dt, JCH = 157.9, 7.6 Hz,
p-Ph), 61.3 (t, JCH = 138.8 Hz, NCH2), 59.8 (q, JCH = 139.0 Hz,
NCH3). Anal. Calcd for C33H46N3BRu: C, 66.30; H, 7.76;
N, 7.03. Found: C, 66.30; H, 7.76; N, 7.08. IR (ATR); 3050,
2997, 2982, 1950 (νRu-H), 1478, 1458, 1427, 1291, 1157, 1014,
844, 792, 745, 733, 708 cm-1
.
H/D Exchange Reaction of 2-PF6 with CD3OD. A Roto
Tite NMR sample tube was charged with 2-PF6 (2.3 mg,
(25) Shima, T.; Kato, T.; Suzuki, H. Unpublished work (2001).

344 Organometallics, Vol. 29, No. 2, 2010
Shima et al.
0.0060 mmol) and THF-d8 (0.40 mL). CD3OD (20 μL, 0.49
mmol) was added, and the H/D exchange reaction was moni-
tored at room temperature by means of 1H NMR spectroscopy.
H/D Exchange Reaction of 2-PF6 with THF-d8. A Roto Tite
NMR sample tube was charged with 2-PF6 (5.0 mg, 12 μmol)
and THF-d8 (0.42 mL). After the sample tube was evacuated
at -196 °C, argon (1 atm) was introduced. The reaction was
performed at room temperature and monitored by means of 1H
NMR spectroscopy.
H/D Exchange Reaction of 2-PF6 with D2 and THF-d8. A Roto
Tite NMR sample tube was charged with 2-PF6 (4.8 mg,
11 μmol) and THF-d8 (0.40 mL). After the sample tube was
evacuated at -196 °C, D2 (1 atm) was introduced. The reaction
was performed at room temperature and monitored by means of
1H NMR spectroscopy.
[Cn*Ru(μ-H)3IrCp*][PF6] (3-PF6). Methanol (10 mL), 2-PF6
(46.2 mg, 0.110 mmol), and Cp*IrH4 (37.7 mg, 0.114 mmol)
were charged in a reaction flask. The solution was stirred for 14 h
at 60 °C. The color of the solution changed from colorless to
purple. Subsequently, the solvent was removed under reduced
pressure. Washing the residual solid with ether afforded 75.8 mg
(0.101 mmol, 92%) of 3-PF6 as a red-purple solid. Tetraphe-
nylborate salt (3-BPh4) was obtained quantitatively by adding
an equimolar amount of NaBPh4 at room temperature to a
methanol solution of 3-PF6. The preparation of the tetramethyl-
ethylcyclopentadienyl complex [Cn*Ru(μ-H)3Ir(η5-C5Me4Et)]-
[BPh4] (30-BPh4) was carried out in exactly the same manner as
for the parent complex 3-BPh4.
Data for 4-PF6 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 3.43 (s, 9H, NCH3), 3.27 (m, 6H,
-NCHH-HHCN-), 2.97 (m, 6H, -NCHH-HHCN-), 2.17 (s,
15H, Cp*), -19.26 (s, 4H, μ-H and Os-H). 1H NMR (400 MHz,
acetone-d6, -90 °C): 2.6-3.8 (m, 12H, -NCHH-HHCN-),
3.44 (br s, 6H, NCH3), 3.09 (br s, 3H, NCH3), 2.11 (s, 15H, Cp*),
-17.95 (s, 2H, μ-H), -20.54 (s, 1H, μ-H or Os-H), -20.62
(s, 1H, μ-H or Os-H). 13C NMR (100 MHz, acetone-d6,
room temperature): δ 88.7 (s, C5Me5), 61.9 (t, JCH=136.9 Hz,
NCH2), 60.6 (q, JCH = 136.7 Hz, NCH3), 11.7 (q, JCH = 127.1
Hz, C5Me5). Anal. Calcd for C43H60N3BRuOs (4-BPh4): C,
56.02; H, 6.51; N, 4.56. Found: C, 55.62; H, 6.70; N, 4.62. IR
(ATR): 2975, 2909, 2088 (νOs-H), 1455, 1010, 832, 789 cm-1
.
[Ru(PPh3)(μ-η3:η1-Cn*CH2)(μ-H)2IrCp*][PF6] (5-PF6). A 50
mL Schlenk tube was charged with 32.1 mg (0.0430 mmol) of
2-PF6 and 5 mL of toluene. PPh3 (25.7 mg, 0.0981 mmol) was
added, and the reaction mixture was stirred at 60 °C for 67 h.
The color of the solution turned from purple to dark brown.
Subsequently, the solvent was removed under reduced pressure.
Crystallization of the residual solid from methanol afforded
42.9 mg (0.0426 mmol, 99%) of 5-PF6 as a brown microcrystal.
Tetraphenylborate salt (5-BPh4) was obtained quantitatively by
adding an equimolar amount of NaBPh4 at room temperature
to a methanol solution of 5-PF6.
Data for 5-PF6 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 8.10 (m, 4H, Ph), 7.49 (m, 6H, Ph), 7.33
(m, 3H, Ph), 7.14 (t, JHH = 7.4 Hz, 2H, Ph), 4.52 (s, 2H,
Ir-CH2-), 3.53, 3.29, 3.06, 2.99, 2.67, 2.37, (m, 2H ꢀ 6,
-NCHH-HHCN-), 2.83 (s, 6H, NCH3), 1.31 (s, 15H, Cp*),
-25.51 (d, JHP = 13.6 Hz, 2H, μ-H). 13C NMR (100 MHz,
acetone-d6, room temperature): δ 142.1 (d, JCP = 25.9 Hz, Ph),
Data for 3-PF6 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 3.49 (s, 9H, NCH3), 3.14 (m, 6H,
-NCHH-HHCN-), 2.75 (m, 6H, -NCHH-HHCN-), 2.11
(s, 15H, Cp*), -20.75 (s, 3H, μ-H). Anal. Calcd for C19H39-
N3F6PRuIr: C, 30.43; H, 5.25; N, 5.61. Found: C, 30.39; H, 5.08;
N, 5.58.
139.2 (d, JCP=33.1 Hz, Ph), 136.9 (dd, JCH = 163.8 Hz, JCP =
11.0 Hz, Ph), 134.3 (dd, JCH = 160.0 Hz, JCP = 8.0 Hz, Ph),
130.4 (d, JCH = 164.5 Hz, Ph), 129.6 (d, JCH = 153.0 Hz, Ph),
Data for 3-BPh4 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 7.34 (m, 8H, BPh4), 6.93 (t, JHH = 7.2
Hz, 8H, BPh4), 6.78 (t, JHH = 7.2 Hz, 4H, BPh4), 3.50 (s, 9H,
NCH3), 3.15 (m, 6H, -NCHH-HHCN-), 2.77 (m, 6H,
-NCHH-HHCN-), 2.12 (s, 15H, Cp*), -20.72 (s, 3H, μ-H).
13C NMR (100 MHz, acetone-d6, room temperature): δ 165.0
(s, Ph), 137.0 (d, JCH = 152.4 Hz, Ph), 125.9 (d, JCH = 151.5 Hz,
Ph), 122.1 (d, JCH = 155.6 Hz, Ph), 89.7 (s, C5Me5), 61.5 (t, JCH
= 135.4 Hz, NCH2), 60.9 (q, JCH = 135.4 Hz, NCH3), 10.9 (q,
JCH = 127.2 Hz, C5Me5). IR (ATR): 3056, 3036, 2997, 2988,
128.9 (dd, JCH = 163.1 Hz, JCP = 7.2 Hz, Ph), 128.7 (dd, JCH
157.7 Hz, JCP = 8.5 Hz, Ph), 89.7 (s, C5Me5), 70.2 (t, JCH
=
=
137.3 Hz, Ir-CH2-), 65.2 (t, JCH = 136.5 Hz, NCH2), 60.8 (t,
CH = 136.9 Hz, NCH2), 59.5 (q, JCH = 137.3 Hz, NCH3), 58.0
(t, JCH = 138.8 Hz, NCH2), 9.6 (q, JCH = 126.7 Hz, C5Me5). 31
J
P
NMR (162 MHz, acetone-d6, room temperature): δ 261.1 (sept,
JPF=708 Hz, PF6), 72.8 (s, PPh3). CH-HMQC (room tempera-
ture): δH 4.52-δC 70.2; δH 3.53, 3.29-δC 58.0; δH 2.67, 2.37-δC
60.8; δH 3.06, 2.99-δC 65.2; δH 2.83-δC 59.5. IR (ATR): 3055,
2983, 2903, 2814, 1580, 1478, 1456, 1426, 1076, 1010, 703 cm-1
.
2907, 1580, 1453, 1009, 844, 778 cm-1
.
Anal. Calcd for C61H73N3PBRuIr (5-BPh4): C, 61.86; H, 6.17;
N, 3.55. Found: C, 61.74; H, 6.09; N, 4.26.
Data for 30-BPh4 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 7.34 (m, 8H, BPh4), 6.93 (t, JHH = 7.2
Hz, 8H, BPh4), 6.79 (t, JHH = 7.2 Hz, 4H, BPh4), 3.49 (s,
9H, NCH3), 3.13 (m, 6H, -NCHH-HHCN-), 2.75 (m, 6H,
-NCHH-HHCN-), 2.36 (q, JHH = 7.2 Hz, 2H, C5Me4Et),
2.14 (s, 6H, C5Me4Et), 2.13 (s, 6H, C5Me4Et), 1.12 (t, JHH = 7.2
Hz, 3H, C5Me4Et), -20.71 (s, 3H, μ-H). 13C NMR (100 MHz,
acetone-d6, room temperature): δ 165.6 (s, Ph), 165.1 (s, Ph),
164.7 (s, Ph), 164.2 (s, Ph), 137.0 (d, JCH = 152.4 Hz, Ph), 126.0
(d, JCH = 151.0 Hz, Ph), 122.2 (d, JCH = 155.6 Hz, Ph), 94.9 (s,
ipso-C5Me4Et), 89.8 (s, C5Me4Et), 89.6 (s, C5Me4Et), 61.5
(t, JCH = 132.4 Hz, NCH2), 61.0 (q, JCH = 133.3 Hz, NCH3),
18.7 (t, JCH = 129.0 Hz, C5Me4Et), 17.1 (q, JCH = 125.6 Hz,
[Cn*Ru(μ-η1:η2-CHdCH2)(μ-η2:η1-CHdCH2)IrHCp*]-
[PF6] (6-PF6). A 50 mL Schlenk tube was charged with 78.1 mg
(0.105 mmol) of 2-PF6 and 5 mL of methanol. After the solution
was cooled at -78 °C, the reaction flask was degassed by the
vacuum line. Then, 1 atm of acetylene was introduced into the
flask at room temperature. The solution was stirred for 2 h at
room temperature. The color of the solution turned from purple
to brown. After the solvent was removed under reduced pres-
sure, the residual solid was dissolved in acetone. The residual
solid was then purified by the use of column chromatography on
alumina (Merk, Art. No. 1097) with acetone. Removal of the
solvent under reduced pressure afforded 71.7 mg (0.0895 mmol,
85%) of 6-PF6 as a yellow solid.
C5Me4Et), 10.9 (q, JCH = 127.2 Hz, C5Me4Et), 10.8 (q, JCH
127.2 Hz, C5Me4Et).
=
Data for 6-PF6 are as follows. 1H NMR (400 MHz, acetone-
d6, room temperature): δ 6.31 (dd, JHH = 10.8, 8.0 Hz, 1H,
Ru-CHdCH2), 5.61 (ddd, JHH = 11.2, 8.4, 5.8 Hz, 1H,
Ir-CHdCH2), 2.6-3.5 (m, 12H, -NCHH-HHCN-), 3.36
(d, JHH = 8.0 Hz, 1H, Ru-β-CHdCH2), 3.30 (s, 3H, NCH3),
2.78 (s, 3H, NCH3), 2.47 (s, 3H, NCH3), 2.24 (d, JHH = 10.8 Hz,
1H, Ru-β-CHdCH2), 2.09 (s, 15H, Cp*), 1.83 (d, JHH = 8.4
Hz, 1H, Ir-β-CHdCH2), 1.43 (d, JHH = 11.2 Hz, 1H, Ir-β-
CHdCH2), -15.59 (d, JHH = 5.8 Hz, 1H, Ir-H). H-H COSY
(room temperature): δH 6.31-δH 3.36, 2.24; δH 5.61-δH 1.83,
1.43. 13C NMR (100 MHz, acetone-d6, room temperature): δ
[Cn*Ru(μ-H)3OsHCp*][PF6] (4-PF6). Methanol (10 mL),
2-PF6 (57.8 mg, 0.138 mmol), and Cp*OsH5 (51.9 mg, 0.157
mmol) were charged in a reaction flask. The solution was stirred
for 8 h at 70 °C. The color of the solution changed from pale
brown to brown. Subsequently, the solvent was removed under
reduced pressure. Washing the residual solid with ether afforded
97.0 mg (0.130 mmol, 94%) of 4-PF6 as a brown solid. Tetra-
phenylborate salt (4-BPh4) was obtained quantitatively by add-
ing an equimolar amount of NaBPh4 at room temperature to a
methanol solution of 4-PF6.

Article
Organometallics, Vol. 29, No. 2, 2010 345
Table 1. Crystallographic Data for 2-PF6, 30-BPh4, 4-BPh4, 5-BPh4, and 6-PF6
2-PF6
30BPh4 C3H6O
4-BPh4
5-BPh4
6-PF6
3
formula
C9H26F6N3PRu
422.37
monoclinic
P21/n (No. 14)
12.6272(4)
9.7739(3)
C47H67OBN3IrRu
994.12
C43H60BN3OsRu
921.02
C61H73BIrN3PRu
1183.27
triclinic
P1 (No. 2)
14.1656(10)
14.5411(8)
15.0940(8)
114.322(4)
92.068(2)
99.0750(10)
2780.0(3)
2
1.414
243(2)
2.731
55
18 579
11 767
0.0465
0.1306
C23H43F6IrN3PRu
799.84
monoclinic
P21/n (No. 14)
8.6647(2)
formula wt
cryst syst
space group
triclinic
P1 (No. 2)
13.6186(19)
15.153(2)
11.441(2)
94.572(18)
107.210(12)
89.502(14)
2247.8(6)
2
1.469
243(2)
3.330
55
10 753
10 319
0.0498
0.1280
triclinic
P1 (No. 2)
11.1261(6)
11.2942(5)
16.5755(6)
91.561(2)
93.371(2)
100.850(2)
2040.55(16)
2
1.499
243(2)
3.513
55
15 016
9157
0.0334
0.0835
˚
a, A
˚
b, A
15.1351(4)
21.3172(6)
˚
c, A
14.2836(6)
R, deg
β, deg
γ, deg
117.0460(12)
92.4830(10)
3
˚
V, A
Z
1570.06(10)
4
1.787
153(2)
1.156
60
18 743
4833
0.0265
0.0677
185
2792.94(13)
4
1.902
253(2)
5.415
55
12 253
6376
0.0410
0.1145
256
Dcalcd, g/cm3
temp, K
μ(Mo KR), mm-1
2θmax, deg
no. of rflns collected
independent reflections
R1
wR2
no. of params
GOF
497
1.027
463
1.048
625
1.051
1.105
1.038
139.2 (d, JCH = 137.8 Hz, Ru-CHdCH2), 110.2 (d, JCH
151.5 Hz, Ir-CHdCH2), 94.5 (s, C5Me5), 62.3 (t, JCH = 137.9
Hz, NCH2), 62.2 (t, JCH = 137.9 Hz, NCH2), 61.9 (t, JCH
137.7 Hz, NCH2), 61.6 (t, JCH = 137.2 Hz, NCH2), 59.5 (t,
CH = 138.8 Hz, NCH2), 58.2 (t, JCH = 135.1 Hz, NCH2), 58.1
=
triple-ζ SDD basis sets for Ru. For N and H, 6-311G(d,p) basis
sets were employed, and for C, 6-31G(d) was used. All calcula-
tions were performed by utilizing the Gaussian03 program.28
The molecular structure was drawn by using the GaussView
version 4.1.2 program.29 Frequency calculations at the same
level of theory as geometry optimizations were performed on the
optimized structure to ensure that minima exhibit only positive
frequency. Information on the atom coordinates (xyz files) for
all optimized structures is collected in the Supporting Informa-
tion.
=
J
(t, JCH = 149.9 Hz, Ru-β-CHdCH2), 56.9 (q, JCH = 138.9 Hz,
NCH3), 56.6 (t, JCH = 149.8 Hz, Ir-β-CHdCH2), 53.8 (q,
JCH = 135.1 Hz, NCH3), 52.8 (q, JCH = 137.7 Hz, NCH3), 10.0
(q, JCH = 126.8 Hz, C5Me5). C-H HMQC (room temperature):
δC 139.2-δH 6.31; δC 58.1-δH 3.36, 2.24; δC 110.2-δH 5.61;
δC 56.6-δH 1.83, 1.43. IR (cm-1): 2959, 2901, 2857, 1458, 1302,
1010, 835, 785, 657, 634. Anal. Calcd for C23H43N3F6PRuIr: C,
34.53; H, 5.38; N, 5.26. Found: C, 34.64; H, 5.32; N, 5.03.
X-ray Data Collection and Reduction. Crystals suitable for X-
ray analysis of 2-PF6, 30-BPh4, 4-BPh4, 5-BPh4, and 6-PF6 were
obtained from MeOH (for 2-PF6 at -30 °C), acetone (for 30-
BPh4 at 4 °C, for 4-BPh4 at room temperature), CH3CN/MeOH
(for 5-BPh4 at room temperature), or acetone/MeOH (for 6-PF6
at room temperature). The crystals were mounted on glass
fibers. The data were collected on a Rigaku AFC-7R four-circle
diffractometer or a Rigaku RAXIS-RAPID imaging plate
equipped with graphite-monochromated Mo KR radiation
˚
(λ = 0.710 69 A) in the 5° < 2θ < 60° range. The data were
processed using the TEXSAN crystal structure analysis pack-
age30 operated on an IRIS Indigo computer. Atomic scattering
factors were obtained from the standard sources. In reduction of
the data, Lorentz/polarization corrections and empirical ab-
sorption corrections based on azimuthal scans were applied for
each structure.
Computational Details. Density functional theory (DFT)
calculations were carried out at the B3PW91 level26 in conjunc-
tion with the Stuttgart/Dresden ECP27 and associated with
Structure Solutions and Refinement. The structures were
solved by the Patterson method (DIRDIF94,31 PATTY32) and
expanded using Fourier techniques. The non-hydrogen atoms
were refined on full-matrix least squares on F2 using SHELXL-
97 program systems.33 For 4-BPh4, disorder at the some of
the Cn* methylene carbons was refined at a ratio of 50:50. For
6-PF6, disorder at the C5Me5 ligand was refined at a ratio of
50:50. The hydrogen atoms, except those bonded to metals, were
included in calculation positions and refined using a riding
(26) (a) Becke, A. D. Phys. Rev. 1988, A38, 3098. (b) Becke, A. D.
J. Chem. Phys. 1993, 98, 5648. (c) Perdew, J. P.; Wang, Y. Phys. Rev. 1992,
B45, 13244.
(27) Andrae, D.; Haussermann, U.; Dolg, M.; Stoll, H.; Preuss, H.
Theor. Chim. Acta 1990, 77, 123.
(28) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A.; Vreven, T.; Kudin,
K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone,
V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.;
Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai,
H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken,
V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev,
O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.;
Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.;
Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas,
O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.;
Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov,
B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.;
Fox, D. J.; Keith, T.; Laham, A.; Peng, C. Y.; Nanayakkara, A.;
Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.;
Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03, Revision D.02;
Gaussian, Inc., Wallingford, CT, 2004.
(29) Dennington, R., II; Keith, T.; Millam, J. GaussView, Version
4.1; Semichem, Inc., Shawnee Mission, KS, 2007.
(30) TEXSAN, Crystal Structure Analysis Package; Molecular Struc-
ture Corp., The Woodlands, TX, 1992.
(31) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
de Gelder, R.; Israel, R.; Smits, J. M. M. DIRDIF94; University of
Nijmegen, Nijmegen, The Netherlands, 1994.
(32) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C.
PATTY; University of Nijmegen, Nijmegen, The Netherlands, 1992.
(33) Scheldrick, G. M. SHELXL-97: Program for Crystal Structure
€
€
Solution; University of Gottingen, Gottingen, Germany, 1997.

346 Organometallics, Vol. 29, No. 2, 2010
Shima et al.
model. The metal-bound hydrogen atoms of 30-BPh4, 4-BPh4,
and 5-BPh4 (H1) were located on difference Fourier maps.
Crystal data and analysis results are given in Table 1.
(No. 18105002) from the Japan Society of the Promotion
of Science.
Supporting Information Available: Text, tables, figures, and
CIF files giving details of the H/D exchange reactions of 2-PF6
with D2 and with THF-d8, DFT calculations, and X-ray crystal-
lographic data for 2-PF6, 30-BPh4, 4-BPh4, 5-BPh4, and 6-PF6.
This material is available free of charge via the Internet at http://
pubs.acs.org.
Acknowledgment. The present work was supported by
a Grant-in-Aid for Science Research on Priority Research
(No. 18064007, Synergy of Elements) from the Ministry
of Education, Culture, Sports, Science, and Technology
of Japan and by a Grant-in-Aid for Science Research (S)