Synthesis and reactivity of iridium and rhodium silyl complexes supported by a bipyridine ligand

Article abstract of DOI:10.1021/om900385a

The rhodium and iridium complexes [('Bu₂bpy)₂M(μ- Cl)]₂ (M = Rh (1), Ir (2)) containing the bidentate 'Bu ₂bpy (4,4'-di-tert-butyl-2,2'-bipyridyl) ligand were prepared. Dimeric complexes 1 and 2 react with HSiPh

Full text of DOI:10.1021/om900385a

5072 Organometallics 2009, 28, 5072–5081
DOI: 10.1021/om900385a
Synthesis and Reactivity of Iridium and Rhodium Silyl Complexes
Supported by a Bipyridine Ligand
Jennifer L. McBee and T. Don Tilley*
Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences
Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
Received May 12, 2009
The rhodium and iridium complexes [(tBu2bpy)2M(μ-Cl)]2 (M = Rh (1), Ir (2)) containing the biden-
tate tBu2bpy (4,40-di-tert-butyl-2,20-bipyridyl) ligand were prepared. Dimeric complexes 1 and 2 react
with HSiPh3 to give [(tBu2bpy)MH(SiPh3)(μ-Cl)]2 in good yields (M = Rh (3) 92%, Ir (4) 90%). Addi-
tion of PiPr3 to 3 or 4 gave monomeric crystalline complexes of the type (tBu2bpy)MH(SiPh3)Cl(PiPr3)
(M = Rh (7) and Ir (8)), which adopt a slightly distorted octahedral coordination geometry with the
tBu2bpy ligand occupying sites trans to the hydride and chloride ligands, as determined by X-ray
crystallography. Salt metathesis reactions of 7 and 8 produced (tBu2bpy)MH(SiPh3)(R)PiPr3 as
t
monomeric octahedral complexes with the Bu2bpy ligand occupying sites trans to the hydride and
R substituents (M=Rh, R=H (11) and M=Ir, R=H (12), Me (14), and Ph (15)). Salt metathesis
reactions with 3 and 4 also generated the dimeric, dicationic complexes [(tBu2bpy)M(SiPh3)(μ-H)]2-
[B(C6F5)4]2, where M = Rh (16) or Ir (17). Thermolysis of 15 at 100 ꢀC in C6H6 for 1 day produced 12
and Ph4Si in 47% yield, and heating 15 in the presence of 1 equiv of HSiR3 (R = Ph, Et) also gave 12, as
well as the Si-C coupled product PhSiR3 in >95% yield.
Introduction
Most notably, a bipyridyl-supported iridium catalyst gener-
ated by the combination of [(cod)Ir(OMe)]2 (cod = 1,5-
Transition metal complexes supported by the bpy (2,20-
bipyridyl) ligand play an important role in electronic appli-
cations,1-7 supramolecular chemistry,8 and catalysis.9-17
Not surprisingly, bpy complexes have also been examined
as catalysts for transformations involving organosilanes.
t
cyclooctadiene) and 2 equiv of Bu2bpy (4,40-di-tert-butyl-
2,20-bipyridine) has been found to catalyze the silylation
of arenes under mild conditions; however, isolation of
iridium silyl complexes from this system has not been
reported.12,13,17 This reaction mixture has also been found
to catalyze silane borylation and the catalytic borylation of
arenes.16 More recently, the iridium silyl complex (tBu2bpy)-
Ir(Me)(SiMe3)(CH2SiMe3) was isolated from reaction of
(tBu2bpy)Ir(dmf)Cl3 with 3 equiv of Me3SiCH2MgCl. How-
ever, little is known about the chemistry of this interesting
dialkyl silyl complex.18
Related research in these laboratories has shown that
anionic ligands analogous to bpy support reactive rhodium
and iridium complexes that engage in bond activation chem-
istry. The monoanionic, chelating 2-(2-pyridyl)indolide
(PyInd) ligand has been found to stabilize coordinatively
unsaturated Ir(V) and Rh(V) bis(silyl) dihydride complexes,
one of which, the Rh(V) bis(silyl) dihydride (PyInd)Rh(H)2-
(SiEt3)2, mediates the catalytic dehydrochlorinative coupling
of chlorobenzene with triethylsilane.19 A related system,
derived from the monoanionic ligand, 3,5-diphenyl-2-(2-
pyridyl)pyrrolide (PyPyr), supports analogous, coordina-
tively unsaturated Ir(V) and Rh(V) bis(silyl) dihydride
complexes.20 Interestingly, one of these Rh(V) bis(silyl) di-
hydrides, (PyPyr)Rh(H)2(SitBuPh2)2, was found to undergo
*Corresponding author. E-mail: tdtilley@berkeley.edu.
(1) Dixon, I. M.; Collin, J.-P.; Sauvage, J.-P.; Flamigni, L.; Encinas,
S.; Barigelletti, F. Chem. Soc. Rev. 2000, 29, 385–391.
(2) Bergeron, S. F.; Watts, R. J. J. Am. Chem. Soc. 1979, 101, 3151–
3156.
(3) Garces, F. O.; Watts, R. J. Inorg. Chem. 1990, 29, 582–584.
(4) Watts, R. J. Inorg. Chem. 1981, 20, 2302–2306.
(5) Watts, R. J.; Bergeron, S. F. J. Phys. Chem. 1979, 83, 424–425.
(6) Watts, R. J.; Missimer, D. J. Am. Chem. Soc. 1978, 100, 5350–
5357.
(7) Balzani, V.; Juris, A.; Venturi, M.; Campagna, S.; Serroni, S.
Chem. Rev. 1996, 96, 759–834.
(8) Balzani, V.; Bergamini, G.; MArchioni, F.; Ceroni, P. Coord.
Chem. Rev. 2006, 250, 1254–1266.
(9) Aresta, M.; Quaranta, E.; Ciccarese, A. J. Mol. Catal. 1987, 41,
355–359.
(10) Yang, H.; Gao, H.; Angelici, R. J. Organometallics 2000, 19,
622–629.
(11) Yang, H.; Gao, H.; Angelici, R. J. Organometallics 1999, 18,
2285–2287.
(12) Ishiyama, T.; Sato, K.; Nishio, Y.; Miyaura, N. Angew. Chem.,
Int. Ed. 2003, 42, 5346–5348.
(13) Ishiyama, T.; Sato, K.; Nishio, Y.; Saiki, T.; Miyaura, N. Chem.
Commun. 2005, 5065–5067.
(14) Kunz, D.; Hartwig, J. F.; Webster, C. E.; Fan, Y.; Hall, M. B. J.
Am. Chem. Soc. 2003, 125, 858–859.
(15) Boller, T. M.; Murphy, J. M.; Hapke, M.; Ishiyama, T.;
Miyaura, N.; Hartwig, J. F. J. Am. Chem. Soc. 2005, 127, 14263–14278.
(16) Boebel, T. A.; Hartwig, J. F. Organometallics 2008, 27, 6013–
6019.
(18) Sau, Y.-K.; Lee, H.-K.; Williams, I. D.; Leung, W.-H. Chem.;
Eur. J. 2006, 12, 9323–9335.
(19) Karshtedt, D.; Bell, A. T.; Tilley, T. D. Organometallics 2006, 25,
4471–4482.
(17) Saiki, T.; Nishio, Y.; Ishiyama, T.; Miyaura, N. Organometallics
2006, 25, 6068–6073.
(20) McBee, J. L.; Escalada, J. M.; Tilley, T. D. J. Am. Chem. Soc.,
in press.
r
pubs.acs.org/Organometallics
Published on Web 08/14/2009
2009 American Chemical Society

Article
Organometallics, Vol. 28, No. 17, 2009 5073
silane exchange through a 14-electron intermediate of the
type (PyPyr)RhH(SitBuPh2).
Similarly, reaction of 2 equiv of HSiPh3 with 2 in benzene
at 25 ꢀC gave the red solid [(tBu2bpy)IrH(SiPh3)(μ-Cl)]2 (4) in
90% yield. The 1H NMR spectrum of 4 exhibits an upfield
singlet at -17.21 ppm for the hydride ligand, and a silyl
resonance at -20.5 ppm was observed in the 29Si{1H} NMR
spectrum. Also, thermolysis of 4 at 60 ꢀC for 8 h in C6D6
resulted in loss of 1 equiv of HSiPh3 to regenerate 2 (by 1H
NMR spectroscopy).
Given the observed bond activation chemistry for com-
plexes of the type (N-N0)MH2(SiR3)2 (where M = Rh, Ir,
N-N0 = anionic ligand) and their unusual structural and
electronic properties, it was of interest to investigate related
complexes containing a neutral, chelating ligand with nitro-
gen donor atoms (N-N). Although it is difficult to envision
pentavalent complexes supported by neutral N-N ligands,
species of the type (N-N)MH2(SiR3)(L) and (N-N)MH-
(SiR3)2(L) should be accessible. Such complexes might be
expected to react via dissociation of L, or by reductive
elimination, to generate 16-electron intermediates. The pur-
pose of the investigation described here is to define reactivity
t
modes for rhodium and iridium complexes of the Bu2bpy
ligand, in search of fundamental steps that may be of use in
catalytic bond activation chemistry.
Results and Discussion
Addition of HSiEt3 to [(tBu2bpy)M(μ-Cl)]2 also resulted in
oxidative addition of the Si-H bond to the metal center.
Specifically, addition of 2 equiv of HSiEt3 to a benzene-d6
solution of [(tBu2bpy)Rh(μ-Cl)]2 in a J. Young NMR tube
generated 1 equiv of [(tBu2bpy)RhH(SiEt3)(μ-Cl)]2 (5) after
5 min at 25 ꢀC (by NMR spectroscopy; eq 2). The 1H NMR
spectrum is consistent with the formation of 5, which exhibits
a resonance for a rhodium hydride ligand at -15.22 ppm,
and a silyl resonance at 19.0 ppm was located in the 29Si{1H}
NMR spectrum. However, [(tBu2bpy)RhH(SiEt3)(μ-Cl)]2
loses HSiEt3 at 25 ꢀC over 4 h, leading to difficulties in its
isolation. In comparison, loss of silane does not readily occur
for the iridium analogue, and an analogous synthesis pro-
duces [(tBu2bpy)IrH(SiEt3)(μ-Cl)]2 (6), which can be isolated
as a red solid in 75% yield. The NMR shifts for 6 include an
upfield singlet for the iridium hydride at -17.26 ppm in the
1H NMR spectrum and a silyl resonance at -1.9 ppm in
the 29Si{1H} NMR spectrum.
Synthesis of [(tBu2bpy)M(μ-Cl)]2 Complexes. Although
the M(III) complexes (tBu2bpy)M(dmf)Cl3 have been re-
ported,18,21 M(I) precursors supported by Bu2bpy have
t
not been described. To access Rh(I) and Ir(I) coordination
complexes of tBu2bpy, the chloride-bridged precursors
[(olefin)2M(μ-Cl)]2 were treated with tBu2bpy. A procedure
analogous to that reported for the synthesis of [(bpy)M(μ-
Cl)]2 was used.9,22 Addition of 2 equiv of tBu2bpy to
[(C2H4)2Rh(μ-Cl)]2 in benzene, followed by stirring for 1 h
at 25 ꢀC, produced [(tBu2bpy)Rh(μ-Cl)]2 (1) as a purple
powder in 95% yield (eq 1). In a similar manner, 2 equiv
of tBu2bpy was added to [(coe)2Ir(μ-Cl)]2 (coe=cyclooctene)
in C6H6 to obtain [(tBu2bpy)Ir(μ-Cl)]2 (2) as a red powder in
92% yield. The 1H NMR spectra of 1 and 2 possess a
downfield resonance, at 9.25 and 9.55 ppm, respectively,
for the tBu2bpy proton nearest the metal center.
Synthesis and Characterization of Mononuclear (tBu2bpy)-
MH(SiPh3)Cl(PR3) Complexes. To explore the chemistry
of monomeric silyl hydride complexes, phosphines were
added to complexes 3 and 4 to cleave the dimeric units.
Reaction of PiPr3 with 3 in benzene for 4 h at 25 ꢀC gave
(tBu2bpy)RhH(SiPh3)Cl(PiPr3) (7) as a purple solid in 72%
yield (eq 3). The 1H NMR spectrum of 7 contains an upfield
doublet of doublets at -16.00 ppm for the hydride ligand,
with coupling to both rhodium (JRhH =10 Hz) and phos-
phorus (JHP = 20.0 Hz). The 29Si NMR spectrum of 7
possesses a silyl resonance at -9.3 ppm (JSiRh = 20.0 Hz),
which represents a 29 ppm upfield shift from that of 3. A 2D
NOESY spectrum of 7 confirms that the silyl and phos-
phine ligands are trans to each other, while the chloride,
Reactions of [(tBu2bpy)M(μ-Cl)]2 with Silanes. Treatment
of a benzene solution of 1 with 2 equiv of HSiPh3 gave the
maroon solid [(tBu2bpy)RhH(SiPh3)(μ-Cl)]2 (3) in 92% yield
after 1 h at 25 ꢀC (eq 2). The 1H NMR spectrum of 3 contains
an upfield doublet at -14.80 ppm (JRhH = 25 Hz) for the
rhodium hydride ligand and six resonances for the tBu2bpy
ligand, revealing that the pyridyl groups are in chemically
different environments. A 2D NOESY experiment demon-
strated that the hydride ligand is trans to a pyridine donor,
while the silyl ligand occupies the position trans to a chloride
ligand. A silyl resonance at 20.6 ppm in the 29Si{1H} NMR
spectrum is consistent with a simple silyl ligand on rho-
dium.23 The thermolysis of 3 at 60 ꢀC for 8 h in C6D6 resulted
in loss of 1 equiv of HSiPh3 (and not ClSiPh3) to give 1 (by 1H
NMR spectroscopy).
t
hydride, and Bu2bpy ligands adopt a mer arrangement.
X-ray quality crystals of 7 were obtained by vapor diffusion
of pentane into a THF solution at 25 ꢀC (Figure 1). Com-
pound 7 adopts a slightly distorted octahedral geometry, as
indicated by the —SiRhP angle of 160.87(3)ꢀ. The silyl and
phosphine groups are slightly bent toward the hydride
ligand, resulting in a —SiRhH and —PRhH angle of 75(1)ꢀ
and 86(1)ꢀ, respectively. For comparison, the—SiRhCl angle
is 90.01(3)ꢀ.
The iridium analogue was synthesized by addition of 2
equiv of PiPr3 to a solution of 4 in benzene to produce
(tBu2bpy)IrH(SiPh3)Cl(PiPr3) (8) as a red solid in 80% yield.
The 1H NMR spectrum of 8 contains an upfield doublet at
-16.68 (JHP=15.0 Hz) for the iridium hydride ligand with a
(21) Sau, Y.-K.; Chan, K.-W.; Zhang, Q.-F.; Williams, I. D.; Leung,
W.-H. Organometallics 2007, 26, 6338–6345.
(22) Pamies, O.; Backvall, J.-E. Chem.;Eur. J. 2001, 7, 5052–5058.
(23) Corey, J. Y.; Braddock-Wilking, J. Chem. Rev. 1999, 99, 175–
292.

5074 Organometallics, Vol. 28, No. 17, 2009
McBee and Tilley
Figure 1. ORTEP diagram of 7 with thermal ellipsoids shown
at the 50% probability level. Hydrogen atoms and the disor-
dered tert-butyl groups are omitted for clarity. Selected bond
Figure 2. ORTEP diagram of 8 with thermal ellipsoids shown
at the 50% probability level. Hydrogen atoms are omitted for
clarity. Selected bond lengths (A): Ir1-N1 = 2.027(2), Ir1-N2
˚
˚
lengths (A): Rh1-N1 = 2.022(2), Rh1-N2 = 2.150(3), Rh1-
Si1 = 2.362(1), Rh1-Cl1 = 2.3816(8), Rh1-P1 = 2.4817(9),
and Rh1-H1 =1.62(4). Selected bond angles (deg): N1-Rh1-
N2 = 78.2(1), N1-Rh1-Si1 = 89.35(7), N2-Rh1-Si1 =
96.24(7), Si1-Rh1-Cl1= 90.01(3), N1-Rh1-P1 = 93.04(7),
N2-Rh1-P1 = 102.83(7), Si1-Rh1-P1 = 160.87(3), and
Si1-Rh1-H1 = 75(1).
= 2.112(1), Ir1-Si1 = 2.3821(7), Ir1-Cl1 = 2.3959(7), Ir1-P1
= 2.4093(7), and Ir1-H1 = 1.55(3). Selected bond angles (deg):
N1-Ir1-N2 = 78.05(8), N1-Ir1-Si1= 92.22(6), N2-Ir1-Si1
= 95.10(5), Si1-Ir1-Cl1 = 83.85(2), N1-Ir1-P1 = 95.67(6),
N2-Ir1-P1 = 99.54(5), Si1-Ir1-P1 = 164.52(2), and Si1-
Ir1-H1 = 80(1).
JSiH coupling constant of 15.0 Hz, indicating little interac-
tion between the silyl and hydride ligands. As with the
rhodium analogue, the 2D NOESY spectrum of 8 is con-
sistent with the geometry shown in eq 3. This is confirmed by
the X-ray structure (Figure 2), where 8 exhibits a slight
distortion from octahedral geometry as indicated by the
—SiIrP angle of 164.52(2)ꢀ and small —SiIrH and —PIrH
angles (80(1)ꢀ, 86(1)ꢀ). Interestingly, the —SiIrCl angle in 8
(83.85(2)ꢀ) is somewhat smaller than the comparable para-
meter in 7 (90.01(3)ꢀ).
Figure 3. ORTEP diagram of 11 with thermal ellipsoids shown
at the 50% probability level. Hydrogen atoms are omitted
˚
for clarity. Selected bond lengths (A): Rh1-N1 = 2.120(1),
Rh1-N2=2.123(1), Rh1-Si1=2.3379(7), Rh1-P1=2.3596(7),
Rh1-H1=1.50(2), and Rh1-H2=1.46(3). Selected bond angles
(deg): N1-Rh1-N2=76.87(7), N1-Rh1-Si1 = 94.17(6), N2-
Rh1-Si1=101.84(6), N1-Rh1-P1 = 104.06(6), N2-Rh1-P1
=97.52(6), Si1-Rh1-P1 = 155.97(2), N1-Rh1-H1 = 170(1),
N2-Rh1-H1 = 99.3(9), Si1-Rh1-H1 = 77.6(9), N1-Rh1-
H2 = 102(1), N2-Rh1-H2 = 176.3(1), Si1-Rh1-H2 = 74(1),
and H1-Rh1-H2 = 81(1).
Analogous compounds containing PPh3 were synthesized
in a similar manner and characterized as (tBu2bpy)RhH-
(SiPh3)Cl(PPh3) (9) (92%) and (tBu2bpy)IrH(SiPh3)Cl-
(PPh3) (10) (88%). However, these systems were found
to be less useful, since it proved difficult to distinguish
between the silicon and phosphorus atoms in X-ray crystal
structures.
(11) in 77% yield (eq 4). The 1H NMR spectrum of 11 reveals
an upfield resonance at -16.06 ppm (JHP=21.0 Hz, JRhH
13.5 Hz) that corresponds to two chemically equivalent
=
Synthesis of Dihydride, Alkyl Hydride, and Aryl Hydride
Complexes. Silyl dihydride, alkylsilyl hydride, and arylsilyl
hydride complexes of rhodium and iridium were targeted,
since such species might represent products of various bond
activations (e.g., C-H, Si-H, Si-C). In fact, the related
complex (tBu2bpy)Ir(SiMe3)Me(CH2SiMe3) is produced by
Si-C cleavage.18 These types of complexes also represent
models for intermediates in catalytic processes, such as
hydrosilylation and silane-hydrocarbon dehydrocoupling,
that feature such bond activations.
1
hydride ligands. Furthermore, the H NMR spectrum ex-
hibits only three resonances for the pyridyl ring hydrogens of
t
the Bu2bpy ligand, indicating the presence of a molecular
plane of symmetry. A downfield shifted 29Si{1H} NMR
resonance at 24.4 ppm (JSiP = 173.0 Hz, JSiRh = 11.4 Hz)
and an upfield shifted 31P{1H} resonance at 44.9 ppm
(JPRh = 91.0 Hz) were also observed for 11. Suitable crystals
of 11 were grown for an X-ray crystallographic analysis by
the slow evaporation of a THF solution at 25 ꢀC, and the
molecular structure (Figure 3) indicates that both hydrides
Addition of 1 equiv of LiBEt3H to a -78 ꢀC THF solution
of 7 provided the purple solid (tBu2bpy)Rh(H)2(SiPh3)PiPr3

Article
Organometallics, Vol. 28, No. 17, 2009 5075
Figure 4. ORTEP diagram of 12 with thermal ellipsoids shown
at the 50% probability level. Hydrogen atoms are omitted for
˚
clarity. Selected bond lengths (A): Ir1-N1 = 2.103(2), Ir1-
Figure 5. ORTEP diagram of 14 with thermal ellipsoids shown
at the 50% probability level. Hydrogen atoms and the THF
molecule are omitted for clarity. Selected bond lengths (A): Ir1-
N1 = 2.096(3), Ir1-N2 = 2.119(3), Ir1-C1 = 2.136(4), Ir1-P1
= 2.368(1), Ir1-Si1 = 2.370(1), and Ir1-H1 = 1.52(4). Selected
bond angles (deg): N1-Ir1-N2 = 76.8(1), N1-Ir1-P1 =
95.19(9), N2-Ir1-P1 = 101.49(9), N1-Ir1-Si1 = 93.51(9),
N2-Ir1-Si1 = 94.82(9), C1-Ir1-Si1 = 83.2(1), P1-Ir1-Si1
= 162.89(4), C1-Ir1-H1 = 88(1), and Si1-Ir1-H1 = 76(1).
N2 = 2.107(2), Ir1-P1 = 2.3326(8), and Ir1-Si1 = 2.3660(8).
Selected bond angles (deg): N1-Ir1-N2 = 76.91(8), N1-Ir1-
P1 =104.60(6), N2-Ir1-P1 = 98.03(6), N1-Ir1-Si1 =
92.41(6), N2-Ir1-Si1 =100.12(6), P1-Ir1-Si1 =157.51(3),
N1-Ir1-H1 =174(1), N2-Ir1-H1 = 99(1), Si1-Ir1-H1 =
83(1), N1-Ir1-H2 = 97(1), N2-Ir1-H2 =172(1), Si1-Ir1-
H2 = 75(1), and H1-Ir1-H2 = 85(1).
˚
t
lie in the plane of the Bu2bpy ligand, with Rh-H bond
distances of 1.46(3) and 1.50(2) A. Slight bending of the silyl
and phoshine ligands toward the hydride is indicated by the
—SiRhH angles of 77.6(9)ꢀ and 74(1)ꢀ and —PRhH angles of
85(1)ꢀ and 86(1)ꢀ. A small distortion from an ideal octahe-
dral geometry is also evident in the —SiRhP bond angle of
THF is known to occur in the presence of an alkyl lithium
reagent,25,26 the methylation was attempted in toluene and
dioxane solvents; however, these reactions produced only
intractable mixtures of products.
˚
˚
155.97(2) A.
A similar synthetic route was used to obtain the iridium
analogue (tBu2bpy)Ir(H)2(SiPh3)PiPr3 (12) as a purple
solid in 78% yield, via reaction of LiBEt3H with 8 in THF.
The 1H NMR spectrum of 12 contains an upfield resonance
at -18.93 ppm (JHP = 16.8 Hz) for the hydride ligand,
and the 29Si{1H} NMR resonance was observed at
6.65 ppm (JSiP = 128.0 Hz). The X-ray structure of 12
confirmed the connectivity determined by NMR spectros-
copy (Figure 4). Further distortion from an ideal octa-
hedral geometry is indicated by the —SiRhP bond angle of
An analogous alkylation procedure, involving addition
of 1 equiv of MeLi (1.6 M in Et2O) to 8 in THF at -78 ꢀC,
did not give an ethylene complex as observed for Rh. Instead,
the expected methyl complex (tBu2bpy)IrH(SiPh3)(Me)PiPr3
(14) was obtained as a purple solid in 82% yield (eq 6).
1
The H NMR spectrum of 14 possesses a broad doublet
for the hydride ligand at -17.29 ppm (JHP = 17.0 Hz) and
a doublet of doublets at 1.02 ppm (JHP = 12.0 Hz) for
the iridium-bound methyl group. A 1H,13C{1H} HSQC
experiment with 14 reveals that the 13C NMR resonance
observed at -34.1 ppm correlates with the 1H resonance at
1.02 ppm.
˚
157.51(1) A.
An attempt to prepare a methyl hydride complex of
rhodium was based on reaction of 1 equiv of MeLi (1.6 M
in Et2O) with 7 at -78 ꢀC in THF over 1 h. After warming to
room temperature, the yellow, known complex (PiPr3)2-
RhCl(C2H4)24 (13) was isolated from the reaction mixture
in 47% yield after crystallization from THF (eq 5). Com-
Suitable crystals of 14 were grown by vapor diffusion
of pentane into a THF solution at -30 ꢀC, and the struc-
ture was determined by X-ray crystallography (Figure 5).
Compound 14 adopts a slightly distorted octahedral geome-
try, with a—SiIrP bond angle of 162.89(4)ꢀ. The silyl group is
slightly bent toward the hydride ligand, as indicated by the
—SiIrH angle of 76(1)ꢀ. The Ir-Me bond distance for 14
1
pound 13 was characterized by H and 31P NMR spectro-
scopies and by X-ray crystallographic analysis. One
equivalent of uncoordinated tBu2bpy was also formed dur-
ing the course of the reaction. Since C2H4 extrusion from
(24) Busetto, C.; D’Alfonso, A.; Maspero, F.; Perego, G.; Zazzetta,
A. J. Chem. Soc., Dalton Trans. 1977, 1828–1834.
(25) Furimsky, E. Appl. Catal. 1983, 6, 159–164.
(26) Yan, F. Q.; Qiao, M. H.; Wei, X. M.; Liu, Q. P.; Deng, J. F.; Xu,
G. Q. J. Chem. Phys. 1999, 111, 8068–8076.

5076 Organometallics, Vol. 28, No. 17, 2009
McBee and Tilley
˚
(2.17(1) A) and the —SiIrC bond angle of 82.5(3)ꢀ are
comparable to the corresponding values found in (PMe3)3-
IrH(SiPh3)(Me) (2.136(4) A and—SiIrC of 83.2(1)ꢀ).27 How-
˚
˚
˚
ever, the Ir-C (2.17(1) A) and Ir-Si (2.371(1) A) bond
distances for 14 are longer than those observed for the five-
coordinate complex (tBu2bpy)Ir(SiMe3)(Me)(CH2SiMe3)
(Ir-C: 2.069(5) A, Ir-Si: 2.279(2) A).18 Complex 14 repre-
sents one of the few examples of an iridium hydridomethyl-
silyl derivative that is not supported by multiple phosphine
ligands.28-37
˚
˚
An attempt to synthesize a rhodium phenylsilyl hydride
complex was based on treatment of 7 with PhLi in C6H6 or
THF. However, these reactions yielded intractable mixtures
(by 1H and 31P NMR spectroscopies). Other phenyl transfer
reagents such as PhSnMe3 also gave complex mixtures by 1H
and 31P NMR spectroscopies. In contrast, the isolation of an
iridium phenyl compound was relatively straightforward.
Addition of 1 equiv of PhLi to a THF solution of 8 at 25 ꢀC
produced (tBu2bpy)IrH(SiPh3)(Ph)PiPr3 (15) as a purple-
brown solid in 90% yield (eq 6). The 1H NMR spectrum of
15 possesses a resonance at -17.48 (JHP = 16.0 Hz) for the
hydride ligand, while the 29Si and 31P{1H} NMR resonances
were observed at -3.42 and 19.36 ppm, respectively.
Synthesis of [(tBu2bpy)M(SiPh3)(μ-H)]2[B(C6F5)4]2 Com-
plexes. To access coordinatively unsaturated, electrophi-
lic complexes related to those described above, attempts
were made to exchange the chloride ligands in [(tBu2bpy)-
MH(SiPh3)(μ-Cl)]2 complexes with the weakly coordinating
anion B(C6F5)-4 .30 Addition of 2 equiv of LiB(C6F5)4(Et2O)2
to a solution of 3 in fluorobenzene gave [(tBu2bpy)Rh-
(SiPh3)(μ-H)]2[B(C6F5)4]2 (16) as a maroon solid in 90%
yield (eq 7). The 1H NMR spectrum of 16 indicates that the
pyridyl groups are equivalent, and an upfield triplet is
observed at -22.73 ppm with JRhH = 33.5 Hz, indicating
that the hydride ligand is bridging between two rhodium
centers. A 29Si{1H} NMR resonance for 16 is observed at
24.1 ppm, verifying retention of the silyl ligand.
Figure 6. ORTEP diagram of 17 with thermal ellipsoids shown
at the 50% probability level. Only one of the two independent
molecules is shown. The hydrogen atoms (except for H(1) and
H(1)0), the B(C6F5)4 anions, and the CH2Cl2 molecule are omit-
˚
ted for clarity. Selected bond lengths (A): Ir1-N1 = 2.034(4),
Ir1-N2 = 2.074(4), Ir1-Si1 = 2.344(1), Ir1-H1 = 1.45(1),
Ir10-H1 = 1.78(1), and Ir1-Cipso = 2.87(1). Selected bond
angles (deg): N1-Ir1-N2 = 77.8(1), N1-Ir1-Si1 = 99.4(1),
N2-Ir1-Si1 = 94.7(1), N1-Ir1-H1 = 96(1), N2-Ir1-H1 =
173(1), and Si1-Ir1-H1 = 88(1).
at 25 ꢀC (Figure 6). The solid-state structure of 17 possesses
half of the molecule in the asymmetric unit, with the two
halves related by inversion, and an Ir-Si bond distance of
˚
2.344(1) A. Interestingly, one of the phenyl substituents of
the silyl ligand is oriented such that it appears to be coordi-
nated to the other iridium center. The resulting Ir-Cipso
distance of 2.87(1) A is consistent with a weak bonding
˚
interaction between the iridium and the ipso carbon of the
silyl ligand. No interaction is observed between the silyl
groups and the hydride ligands, as indicated by the —SiIrH
angle of 88(1)ꢀ.
The iridium analogue of 16 can be prepared in a simi-
lar manner. A solution of 4 in CH2Cl2 was treated with
2 equiv of LiB(C6F5)4(Et2O)2 over 2 h at 25 ꢀC to generate
[(tBu2bpy)Ir(SiPh3)(μ-H)]2[B(C6F5)4]2 (17) as an orange so-
1
lid in 92% yield. The H NMR spectrum of 17 contains a
singlet at -22.51 ppm for the iridium bridging hydride
ligands, and the 29Si{1H} NMR resonance for 17 was located
at -21.0 ppm. X-ray quality crystals of 17 were grown
by vapor diffusion of pentane into a CH2Cl2 solution of 17
Additions of Lewis bases to 16 and 17 were explored to
evaluate the accessibility of the coordination site that pos-
sesses the bonding interaction with the ipso carbon. Addition
of 2 equiv of phosphine (PPh3 or PiPr3) to 16 or 17 gave no
reaction until decomposition after 16 h at 60 ꢀC in CD2Cl2
(by 1H NMR spectroscopy). Similarly, treatment of 16 or 17
with 2 equiv of tertiary silanes (HSiEt3 or HSiPh3) or 2 equiv
of 1-hexene for 16 h at 60 ꢀC in CD2Cl2 gave no reaction, and
(27) Aizenberg, M.; Milstein, D. J. Am. Chem. Soc. 1995, 117, 6456–
64.
(28) Bleeke, J. R.; Thananatthanachon, T.; Rath, N. P. Organome-
tallics 2008, 27, 1354.
(29) Bleeke, J. R.; Thananatthanachon, T.; Rath, N. P. Organome-
tallics 2008, 27, 2436–2446.
(30) Sangtrirutnugul, P.; Tilley, T. D. Organometallics 2007, 26,
5557–5568.
(31) Bleeke, J. R.; Thananatthanachon, T.; Rath, N. P. Organome-
1
only decomposition was observed (by H NMR spectro-
scopy).
tallics 2007, 26, 3904–3907.
An alternate path to 17 was achieved by addition of 1
equiv of LiB(C6F5)4(Et2O)2 to the mononuclear PiPr3 com-
plex 8 in CH2Cl2, which quantitatively produced 17 and 1
equiv of free PiPr3 (by 1H and 31P NMR spectroscopy).
Thermolysis of (tBu2bpy)IrH(SiPh3)(R)PiPr3 Complexes.
The thermolyses of iridium complexes 12, 14, and 15 were
examined to characterize available reductive elimination
pathways, which could serve as models for potential pro-
duct-forming steps. Complexes of the type L2MH(SiR3)R
(32) Peters, J. C.; Feldman, J. D.; Tilley, T. D. J. Am. Chem. Soc.
1999, 121, 9871–9872.
(33) Okazaki, M.; Tobita, H.; Kawano, Y.; Inomata, S.; Ogino, H. J.
Organomet. Chem. 1998, 553, 1–13.
(34) Okazaki, M.; Tobita, H.; Ogino, H. J. Chem. Soc., Dalton Trans.
1997, 3531–3533.
(35) Okazaki, M.; Tobita, H.; Ogino, H. Chem. Lett. 1996, 477–478.
(36) Aizenberg, M.; Milstein, D. Organometallics 1996, 15, 3317–
3322.
(37) Aizenberg, M.; Milstein, D. Angew. Chem. 1994, 106, 344-346
(See also Angew. Chem., Int. Ed. Engl. 1994, 33(3), 317-319).

Article
Organometallics, Vol. 28, No. 17, 2009 5077
Scheme 1
have been found to favor reductive eliminations to form
C-H and Si-H bonds, with either very little or no Si-C
bond formation.36-38 Also, reductive eliminations from
these complexes are expected to produce low-valent inter-
mediates, which should engage in bond activation steps with
appropriate substrates.
NMR spectroscopy). Addition of 1 equiv of HSiPh3 to
a C6H6 solution of 15 followed by heating to 100 ꢀC for
1 day produced no free Bu2bpy, and 12 and Ph4Si were
t
1
produced in g95% yield (by H NMR spectroscopy and
GC-MS).
Heating a C6D6 solution of 12 to 180 ꢀC for 2 days resulted
in no H2 evolution, and complete deuteration of the Ir-H
positions was observed (by 1H and 2H NMR spectroscopy).
After 12 was heated in C6H6 at 180 ꢀC for 2 days, it was
1
recovered in 95% yield (by H NMR spectroscopy). The
Addition of 1 equiv of HSiEt3 to a solution of 15 at 100 ꢀC
produced 12 and PhSiEt3 in g95% yield after 1 day, and no
Ph4Si was formed under these conditions. Interestingly, Si-
C bond formation can also proceed under mild conditions
upon reaction of HSiEt3 with 15. Addition of 10 equiv of
HSiEt3 to a benzene solution of 15 at 25 ꢀC produced 12 and
PhSiEt3, both in g95% yield (based on Ir) after 1 day.
Catalytic Si-C coupling to form PhSiEt3 was not observed
in this reaction, and when 15 was treated with 10 equiv of
HSiPh3 over 16 h at 100 ꢀC, no catalysis was detected (12 and
Ph4Si were both produced stoichiometrically and 9 equiv of
HSiPh3 remained, by 1H NMR spectroscopy and GC-MS).
Heating 12 or 15 in the presence of HSiPh3 and 10 equiv of
the hydrogen acceptor CH2CHtBu did not facilitate catalytic
turnover, and only 1 equiv of 12 was observed in both cases
after 2 days at 100 ꢀC (for the thermolysis of 15, 1 equiv of
thermolysis of 14 was also examined by heating a solution of
the complex in C6D6 to 100 ꢀC. After 5 h, a complex mixture
1
2
of products was observed (by H and H NMR spectro-
scopy), and the activation of C6D6 was indicated by the
2
presence of multiple deuteride resonances in the H NMR
spectrum. The thermolysis of 14 in C6H6 at 100 ꢀC over 5 h
produced 12 and 15 in a 0.88:1 ratio, for a combined 60%
yield (relative to a hexamethylbenzene internal standard),
and CH4 was also observed (eq 8).
The elimination of methane from 14 presumably generates
a reactive Ir(I) silyl intermediate such as [(tBu2bpy)-
Ir(SiPh3)PiPr3], which then participates in bond activation
reactions to give 12 and 15. This intermediate could oxida-
tively add benzene to give one of the decomposition products
(15). To examine the behavior of 15 under these reaction
conditions, a solution of 15 in C6H6 was heated at 100 ꢀC
for 1 day. Workup of the reaction mixture provided 12,
1
Ph4Si was also produced as determined by H NMR spec-
troscopy and GC-MS).
Notably, the transformations described above provide
evidence for C-H activation processes involving benzene.
This was observed in the partial conversion of 14 to 15 in
benzene and in the incorporation of deuterium into the
hydride positions of 12 and 15 in the presence of benzene-
d6. The latter process implies C-H activation by an Ir(I) silyl
t
free Bu2bpy, and Ph4Si, each in 47% yield (eq 9), as
1
confirmed by H NMR spectroscopy and GC-MS of the
t
complex supported by Bu2bpy (Scheme 1). The detailed
organic compounds (integration values were calibrated to a
known quantity of hexamethylbenzene as an internal
standard). Addition of 1 equiv of PiPr3 to a solution of 15
in C6H6 followed by heating at 100 ꢀC for 4 days completely
inhibited the thermolysis, and only 15 and PiPr3 were
observed (by 1H NMR spectroscopy). The inhibition by
added phosphine implies that phosphine dissociation is a
key step in the thermolytic conversion of 15 to give 12.
Thermolysis of 15 in a solution of C6D6 for 1 day at 100 ꢀC
gave a mixture of 12, 12-d1, and 12-d2 (1:2:1) with deuterium
incorporation into the hydride positions (by 1H and 2H
nature of the low-valent species responsible for bond activa-
tions in this system is currently undefined, but related
elimination-addition processes, involving preceding phos-
phine dissociation, have been the subject of mechanistic
investigations.39,40 The observed Si-C reductive elimination
of arylsilanes is also noteworthy, in that it serves as a model
for the product-forming step in catalytic silylations of arenes.
Silyl-aryl reductive eliminations are observed in thermolyses
of 14 and 15 and proceed cleanly in the presence of excess
silane. This implies that silanes are efficient traps for an Ir(I)
hydride intermediate in this system, which would be formed
by the Si-C reductive elimination. A second type of Si-H
activation appears to involve an intermediate Ir(I) phenyl
(38) Cleary, B. P.; Mehta, R.; Eisenberg, R. Organometallics 1995, 14,
2297–2305.

5078 Organometallics, Vol. 28, No. 17, 2009
McBee and Tilley
species, since reaction of HSiEt3 with 15 led to a high yield of
PhSiEt3, presumably via a preceding HSiPh3/HSiEt3 ex-
change process (Scheme 1). However, note that exchange
of HSiEt3 into the dihydride 12 is very slow, since addition of
10 equiv of HSiEt3 to 12 in benzene resulted in no conversion
after 12 days at 100 ꢀC (by 1H NMR spectroscopy).
An interesting comparison can be made with the thermolysis
of (PMe3)3IrH(SiPh3)(Me) in benzene-d6, which generates
CH4 by reductive elimination. Orthometalation of a phenyl
substituent on the silyl ligand gives the final, isolated product,
(PMe3)3IrH(κ2-o-C6H4SiMe2) (48% yield after heating at
95 ꢀC for 2 days).36 A related complex, (PMe3)3IrH(SiEt3)-
(Me), gave both C-H and Si-C reductive elimination (80%
CH4, 20% MeSiEt3) upon heating at 100 ꢀC for 1 day,
presumably via steps similar to those described in Scheme 1.37
Furthermore, the related iridium complex (dppe)IrH(Si-
Ph2H)(Mes)(CO) (dppe = bis(diphenylphosphino)ethane,
Mes = 2,4,6-trimethylphenyl) readily undergoes reductive
eliminations; however, only C-H and Si-H (and no Si-C)
bond formations were observed.38
studies will serve as a basis for the development of such
catalysis.
Experimental Section
General Procedures. All experiments were conducted under
nitrogen using standard Schlenk techniques or in a Vacuum
Atmospheres drybox. Nondeuterated solvents were distilled
under N2 from appropriate drying agents and stored in PTFE-
valved flasks. Deuterated solvents (Cambridge Isotopes) were
vacuum-transferred from appropriate drying agents.
The compounds HSiPh3, HSiEt3, PPh3, MeLi (1.6 M in
Et2O), LiBEt3H (1.0 M in Et2O), and tBu2bpy were purchased
from Aldrich and dried over appropriate drying agents. The
compound PiPr3 was purchased from Strem and used without
further purification. The compounds PhLi,42 [(coe)2Ir(μ-Cl)]2,43
45
[(C2H4)2Rh(μ-Cl)]2,44 and LiB(C6F5)4(Et2O)2 were synthe-
sized according to literature procedures.
Analytical Methods. 1H, 2H, 29Si{1H}, 31P{1H}, and 13C{1H}
NMR spectra were recorded using Bruker AVB 400, AV-500, or
DRX 500 spectrometers equipped with a 5 mm BB probe.
Spectra were recorded at room temperature and referenced to
1
Given the observed Si-C reductive elimination for com-
plex 15, an attempt was made to observe the catalytic
dehydrohalogenation of haloarenes. Reaction of 1 equiv of
15 with 10 equiv of HSiEt3, 10 equiv of PhI (or PhCl), and 10
equiv of LiN(SiMe3)2 gave no coupling of the haloarene, and
1 equiv of 12 and PhSiEt3 were observed after 8 h at 100 ꢀC.
No further change was observed after continued heating of
the residual protonated solvent for H NMR spectrum or to
tetramethylsilane for the 29Si NMR spectrum. 31P{1H} NMR
spectra were referenced relative to 85% H3PO4 external stan-
dard (δ=0). 13C{1H} NMR spectra were calibrated internally
with the resonance for the solvent relative to tetramethylsilane.
Coupling constants in the 1H NMR spectrum (JRhH, JPH, and
1
J
SiH) were determined by 31P-filtered H NMR spectroscopy,
1H{31P} NMR spectroscopy, and 29Si-filtered H NMR spec-
troscopy. Coupling constants in the 29Si NMR spectrum (JSiRh
and JSiP) were determined by comparing a 1H, 29Si{31P} HMBC
NMR spectrum to the 29Si NMR spectrum. Elemental analyses
were performed by the College of Chemistry Microanalytical
Laboratory at the University of California, Berkeley. Identities
of organic products were confirmed by 1H NMR spectroscopy
and by GC-MS, using an Agilent Technologies 6890N GC
system with an HP-5MS column.
1
1
the reaction mixture for 2 days at 120 ꢀC (by H NMR
spectroscopy and GC-MS).
Concluding Remarks
The simple dimeric [(tBu2bpy)M(μ-Cl)]2 complexes allow
synthetic access to monomeric group 9 chlorohydridosilyl
complexes by facile Si-H oxidative addition followed by
phosphine coordination. For iridium, rare examples of
complexes containing hydride, silyl, and hydridocarbyl
(phenyl or methyl) groups have been isolated. Interestingly,
the thermolysis of 15 does not lead to an orthometalation
product, as is observed for the related (PMe3)3IrH-
(SiPh3)(Me),36 but rather to C-Si bond formation to pro-
duce Ph4Si.
The reductive elimination pathways available to 15 are of
relevance to catalytic aryl-Si bond-forming reactions, many
of which employ rhodium-based catalysts. The intermediates
proposed for these reactions often take the form
[M]H(SiR3)Ar. For (PyInd)Rh complexes that have been
found to catalyze Si-C coupling reactions between hydro-
silanes and aryl chlorides, a proposed intermediate is
(PyInd)RhHCl(SiEt3)Ph.19 For the coupling of arenes with
triethylsilane, the catalyst Cp*Rh(H)2(SiEt3)2 is proposed to
go through an intermediate of the type Cp*RhH(SiEt3)2-
Ar.41 Furthermore, the intermediate (dipphen)IrH(SisBu-
F2)n(Ar) (dipphen = 2,9-diisopropyl-1,10-phenanthroline,
n = 1 or 3) has been proposed for the silylation of arenes
with fluorodisilanes.17 Although catalytic Si-C bond-form-
ing reactions have yet to be observed in the (tBu2bpy)M
systems described here, it is hoped that these reactivity
[(tBu2bpy)RhCl]2 (1). A 5 mL benzene solution of Bu2bpy
t
(0.689 g, 2.57 mmol) was added to a 5 mL solution of
[(C2H4)2Rh(μ-Cl)]2 (0.500 g, 1.28 mmol) in benzene. The reac-
tion mixture was stirred for 1 h, and the volatile compounds
were removed in vacuo. The resulting purple solid was extracted
with 5 mL of THF, and the volatile material was then removed in
vacuo. The isolated purple solid was washed with 2 mL of
pentane to give the pure product in 95% yield (0.992 g, 1.22
mmol). 1H NMR (C6D6): δ 9.25 (d, JHH = 6.0 Hz, 2H, ArH),
7.98 (s, 2H, ArH), 7.77 (s, 2H, ArH), 7.63 (d, JHH = 6.0 Hz, 2H,
ArH), 7.37 (d, JHH = 6.0 Hz, 2H, ArH), 7.22 (d, JHH = 6.0 Hz,
2H, ArH), 1.45 (s, 18H, CCH3), 1.38 (s, 18H, CCH3). 13C{1H}
NMR: δ 158.5, 156.9, 150.4, 147.7, 123.7, 123.1, 118.7, 117.2,
35.5, 30.0. Anal. Calcd (%) for C36H48Cl2N4Rh2: C, 53.15, H,
5.95, N, 6.89. Found: C, 52.81, H, 6.25, N, 6.74.
t
[(tBu2bpy)IrCl]2 (2). A 5 mL benzene solution of Bu2bpy
(0.494 g, 1.84 mmol) was added to a 5 mL solution of [(coe)2Ir(μ-
Cl)]2 (0.500 g, 0.921 mmol) in benzene. The reaction mixture was
stirred for 1 h, and the volatile compounds were removed in
vacuo. The resulting red solid was extracted with 5 mL of THF,
and the volatile material was then removed in vacuo. The
isolated red solid was washed with 2 mL of pentane to give the
pure product in 92% yield (0.839 g, 0.840 mmol). 1H NMR
(C6D6): δ 9.55 (d, JHH = 4.5 Hz, 2H, ArH), 8.10 (s, 2H, ArH),
8.06 (d, JHH = 6.0 Hz, 2H, ArH), 7.87 (s, 2H, ArH), 7.61 (d,
J
HH = 6.0 Hz, 2H, ArH), 7.37 (d, JHH = 4.5 Hz, 2H, ArH), 1.49
(39) Maruyama, Y.; Yamamura, K.; Sagawa, T.; Katayama, H.;
Ozawa, F. Organometallics 2000, 19, 1308–1318.
(40) Ozawa, F. J. Organomet. Chem. 2000, 611, 332–342.
(41) Ezbiansky, K.; Djurovich, P. I.; LaForest, M.; Sinning, D. J.;
Zayes, R.; Berry, D. H. Organometallics 1998, 17, 1455–1457.
(42) Beak, P.; Selling, G. W. J. Org. Chem. 1989, 54, 5574–5580.
(43) Van der Ent, A.; Onderdelinden, A. L. Inorg. Synth. 1990, 28,
90–2.
(44) Cramer, R. Inorg. Synth. 1990, 28, 86–8.
(45) Massey, A. G.; Park, A. J. J. Organomet. Chem. 1964, 2, 245–250.

Article
Organometallics, Vol. 28, No. 17, 2009 5079
(s, 18H, CCH3), 1.43 (s, 18H, CCH3). 13C{1H} NMR (CD2Cl2):
170.0, 160.5, 157.5, 150.9, 123.1, 122.2, 118.9, 118.1, 35.0, 34.9.
Anal. Calcd (%) for C36H48Cl2N4Ir2: C, 43.58, H, 4.84, N, 5.65.
Found: C, 39.26, H, 4.74, N, 5.39. This complex was recrystal-
lized from THF, but this did not provide a better agreement for
the combustion analysis. However, the complex is pure by NMR
spectroscopy and proved to be a suitable starting material as
described below.
18H, SiCH2CH3), 0.21 (m, 12H, SiCH2CH3), -17.26 (s, 2H,
IrH). 13C{1H} NMR: δ 160.2, 159.4, 157.9, 157.7, 150.0,
136.2, 128.9, 123.3, 122.1, 118.5, 117.5, 35.1, 30.1, 7.7, 6.4. 1H,
δ -1.9. Anal. Calcd (%) for
C48H80Cl2Ir2N4Si2: C, 47.07, H, 6.58, N, 4.57. Found: C,
46.97, H, 6.38, N, 4.32.
29Si{1H} HMBC NMR:
(tBu2bpy)RhH(SiPh3)Cl(PiPr3) (7). A 5 mL benzene solution
of PiPr3 (0.0866 g, 0.541 mmol) was added to a 5 mL solution of
[(tBu2bpy)RhH(SiPh3)(μ-Cl)]2 (0.360 g, 0.270 mmol) in benzene.
The reaction mixture was stirred for 4 h, and the volatile
material was removed in vacuo. The resulting purple solid was
crystallized by vapor diffusion of pentane into a THF solution
to give purple crystals of the product in 72% yield (0.322 g,
0.390 mmol). 1H NMR (C6D6): δ 10.67 (d, JHH = 5.0 Hz, 1H,
ArH), 8.69 (d, JHH = 5.0 Hz, 1H, ArH), 7.75 (d, JHH = 6.0 Hz,
6H, ArH), 7.39 (s, 1H, ArH), 7.28 (s, 1H, ArH), 7.16 (m
overlapping with benzene-d6, 9H, ArH), 6.90 (d, JHH = 5.0
Hz, 1H, ArH), 6.37 (d, JHH = 5.0 Hz, 1H, ArH), 2.79 (m, 3H,
PCH), 1.53 (m, 18H, PCHCH3), 1.08 (s, 9H, CCH3), 0.95 (s, 9H,
CCH3), -16.00 (dd, JHP = 20.0 Hz, JRhH = 10.0 Hz, 1H, RhH).
13C{1H} NMR: δ 157.9, 156.3, 154.3, 150.8, 136.2, 135.3, 133.0,
130.5, 129.2, 128.2, 126.4, 125.5, 121.9, 118.8, 115.7, 34.8, 34.1,
[(tBu2bpy)RhH(SiPh3)(μ-Cl)]2 (3). A 5 mL benzene solution
of HSiPh3 (0.320 g, 1.23 mmol) was added to a 5 mL solution of
[(tBu2bpy)RhCl]2 (0.500 g, 0.615 mmol) in benzene. The reac-
tion mixture was stirred for 1 h, and the volatile compounds
were removed in vacuo. The resulting maroon solid was dis-
solved with 5 mL of THF, and the reaction mixture was passed
through Celite. The resulting solution was then evacuated to
dryness. The isolated maroon solid was washed with 2 mL of
pentane to give the pure product in 92% yield (0.750 g,
1
0.563 mmol). H NMR (C6D6): δ 9.05 (d, JHH = 5.0 Hz, 2H,
ArH), 8.31 (d, JHH = 6.5 Hz, 2H, ArH), 8.00 (s, 2H, ArH), 7.92
(s, 2H, ArH), 7.56 (d, JHH = 6.5 Hz, 2H, ArH), 7.18 (d, JHH
7.5 Hz, 12H, SiArH), 7.05 (t, JHH = 7.5 Hz, 6H, SiArH), 6.92 (t,
HH = 7.5 Hz, 12H, SiArH), 6.72 (d, JHH = 5.0 Hz, 2H, ArH),
=
J
1.54 (s, 18H, CCH3), 1.46 (s, 18H, CCH3), -14.80 (d, JRhH = 25
Hz 2H, RhH). 13C{1H} NMR: δ 161.2, 159.5, 157.9, 156.4,
150.8, 142.3, 135.5, 129.3, 128.9, 127.8, 126.5, 126.3, 122.5,
117.9, 117.0, 35.1, 30.2. 29Si{1H} NMR: δ 20.6. Anal. Calcd
(%) for C72H80Cl2Rh2N4Si2: C, 64.81, H, 6.04, N, 4.20. Found:
C, 64.75, H, 6.19, N, 4.53.
23.6 (JCP = 13.0 Hz), 19.8. 29Si{1H} NMR: δ -9.3 (m, JSiRh
=
20.0 Hz). 31P{1H} NMR: δ 54.5 (JRhP = 88.0 Hz). Anal. Calcd
(%) for C45H61ClN2PRhSi: C, 65.32, H, 7.43, N, 3.39. Found:
C, 65.06, H, 7.81, N, 3.48.
(tBu2bpy)IrH(SiPh3)Cl(PiPr3) (8). A 5 mL benzene solution of
PiPr3 (0.0530 g, 0.331 mmol) was added to a 5 mL solution of
[(tBu2bpy)IrH(SiPh3)(μ-Cl)]2 (0.250 g, 0.165 mmol) in benzene.
The reaction mixture was stirred for 4 h, and the volatile
compounds were removed in vacuo. The resulting red-orange
solid was dissolved in 5 mL of THF, the reaction mixture was
passed through Celite, and the volatile components were re-
moved under vacuum. The isolated red-orange solid was crystal-
lized by vapor diffusion of pentane into a THF solution to give
red crystals of the product in 80% yield (0.243 g, 0.265 mmol).
1H NMR (C6D6): δ 9.61 (d, JHH = 5.0 Hz, 1H, ArH), 8.32 (d,
[(tBu2bpy)IrH(SiPh3)(μ-Cl)]2 (4). A 5 mL benzene solution of
HSiPh3 (0.262 g, 1.01 mmol) was added to a 5 mL solution of
[(tBu2bpy)IrCl]2 (0.500 g, 0.505 mmol) in benzene. The reaction
mixture was stirred for 1 h, and the volatile compounds were
removed in vacuo. The resulting red solid was dissolved with
5 mL of THF, and the reaction mixture was passed through
Celite. The resulting solution was then evacuated to dryness.
The isolated red solid was washed with 2 mL of pentane to give
the product in 90% yield (0.686 g, 0.455 mmol). 1H NMR
(C6D6): δ 9.10 (d, JHH = 6.5 Hz, 2H, ArH), 8.75 (d, JHH
4.5 Hz, 2H, ArH), 7.90 (s, 2H, ArH), 7.87 (s, 2H, ArH), 7.24 (d,
JHH = 4.5 Hz, 2H, ArH), 7.01 (ov m, 18H, SiArH), 6.86 (t,
JHH = 7.0 Hz, 12H, SiArH), 6.67 (d, JHH = 6.5 Hz, 2H, ArH),
1.49 (s, 18H, CCH3), 1.41 (s, 18H, CCH3), -17.21 (s, 2H, IrH,
T1 = 0.432 s). 13C{1H} NMR: δ 151.7, 139.2, 135.7, 135.5,
133.4, 130.0, 129.8, 128.1, 127.8, 127.1, 124.5, 119.5, 30.1, 26.1.
29Si{1H} NMR: δ -20.5. Anal. Calcd (%) for C72H80Cl2Ir2-
N4Si2: C, 57.16, H, 5.33, N, 3.70. Found: C, 56.80, H, 5.43,
N, 3.66.
=
J
HH = 5.0 Hz, 1H, ArH), 7.78 (s, 1H, ArH), 7.76 (d, JHH = 6.0
Hz, 6H, ArH), 7.71 (s, 1H, ArH), 7.00 (m, 9H, ArH), 6.54 (d,
HH = 5.0 Hz, 1H, ArH), 5.90 (d, JHH = 5.0 Hz, 1H, ArH), 2.21
J
(m, 3H, PCH), 1.00 (m, 18H, PCHCH3), 0.98 (s, 9H, CCH3),
0.95 (s, 9H, CCH3), -16.68 (d, JHP = 15.0 Hz, 1H, IrH).
13C{1H} NMR: δ 158.2, 155.7, 149.8, 144.1, 136.5, 128.0,
126.4, 125.8, 123.8, 122.7, 117.2, 116.5, 34.24, 34.15, 31.5, 29.6
(JCP = 19.4 Hz), 18.6 (JCP = 8.5 Hz). 29Si{1H} HMBC NMR: δ
-13.4 (d, JSiP = 144.5, Hz, JSiH = 15.0 Hz). 31P{1H} NMR: δ
4.35. Anal. Calcd (%) for C45H61ClIrN2PSi: C, 58.96, H, 6.71,
N, 3.06. Found: C, 59.03, H, 6.80, N, 2.99.
[(tBu2bpy)RhH(SiEt3)(μ-Cl)]2 (5). To an NMR tube were
added [(tBu2bpy)RhCl]2 (0.025 g, 0.062 mmol) and 0.5 mL of
a C6D6 solution of HSiEt3 (0.007 g, 0.060 mmol). The NMR
tube was capped, inverted three times, and then placed into the
NMR probe. 1H NMR (C6D6): δ 9.52 (br s, 2H, ArH), 9.20 (br s,
2H, ArH), 7.86 (br s, 4H, ArH), 6.84 (br s, 2H, ArH), 6.74 (br s,
2H, ArH), 1.07 (s, 18H, CCH3), 1.02 (s, 18H, CCH3), 0.96 (t,
JHH = 7.0 Hz, 18H, SiCH2CH3), 0.52 (br m, 12H, SiCH2CH3),
(tBu2bpy)RhH(SiPh3)Cl(PPh3) (9). A 5 mL benzene solution
of PPh3 (0.0982 g, 0.378 mmol) was added to a 5 mL solution of
[(tBu2bpy)RhH(SiPh3)(μ-Cl)]2 (0.250 g, 0.188 mmol) in benzene.
The reaction mixture was stirred for 4 h, and the volatile
compounds were removed in vacuo. The resulting red solid
was dissolved in 5 mL of THF, and the reaction mixture was
passed through Celite. The volatile components were then
removed under vacuum. The resulting red solid was crystal-
lized by vapor diffusion of pentane into a THF solution to give
purple crystals of the product in 92% yield (0.323 g, 0.347
mmol). 1H NMR (C6D6): δ 10.55 (d, JHH = 6.0 Hz, 1H, ArH),
9.06 (s, 1H, ArH), 8.31 (t, JHH = 7.0 Hz, 6H, ArH), 8.17 (d,
1
-15.22 (d, JRhH = 20.0 Hz, 2H, RhH). H, 29Si{1H} HMBC
NMR: δ 19.0.
[(tBu2bpy)IrH(SiEt3)(μ-Cl)]2 (6). A 5 mL benzene solution of
HSiEt3 (0.118 g, 1.02 mmol) was added to a 5 mL solution of
[(tBu2bpy)IrCl]2 (0.500 g, 0.505 mmol) in benzene. The reaction
mixture was stirred for 1 h, and the volatile material was then
removed under vacuum. The resulting red solid was dissolved in
5 mL of THF, the reaction mixture was passed through Celite,
and the volatile material was then removed in vacuo. The
isolated red solid was washed with 2 mL of pentane to give the
J
HH = 4.5 Hz, 1H, ArH), 7.84 (d, JHH = 5.0 Hz, 1H, ArH), 7.66
(d, JHH = 5.5 Hz, 3H, ArH), 7.56 (ov m, 7H, ArH), 7.15-6.87
(ov m, 9H, ArH), 6.16 (d, JHH = 4.5 Hz, 1H, ArH), 1.16 (s,
9H, CCH3), 1.00 (s, 9H, CCH3), -15.15 (dd, JHP = 20.0 Hz,
JRhH = 25.0 Hz, 1H, RhH). 13C{1H} NMR: δ 156.7, 155.1,
154.1, 153.0, 152.3, 137.1, 136.4, 135.8, 134.3, 133.0 (JCP = 8.0
Hz), 132.6, 130.5, 129.8, 128.8, 128.3, 127.1, 126.5, 121.6,
121.3, 116.6, 34.0, 30.0. 1H, 29Si{1H} HMBC NMR: δ -9.1
(dd, JSiP = 151.0 Hz, JSiRh = 40.0 Hz). 31P{1H} NMR
(CD2Cl2): δ 33.2 (d, JRhP = 91.1 Hz). Anal. Calcd (%) for
1
pure product in 75% yield (0.569 g, 0.465 mmol). H NMR
(C6D6): δ 9.72 (d, JHH = 4.0 Hz, 2H, ArH), 9.43 (d, JHH = 5.5
Hz, 2H, ArH), 7.95 (s, 2H, ArH), 7.84 (s, 2H, ArH), 7.49 (d,
JHH = 5.5 Hz, 2H, ArH), 7.13 (d, JHH = 4.0 Hz, 2H, ArH), 1.50
(s, 18H, CCH3), 1.46 (s, 18H, CCH3), 0.37 (t, JHH = 8.0 Hz,

5080 Organometallics, Vol. 28, No. 17, 2009
McBee and Tilley
C54H55ClN2RhPSi: C, 69.78, H, 5.96, N, 3.01. Found: C, 69.60,
H, 6.12, N, 3.30.
(PiPr3)2RhCl(C2H4) (13).
A
5
mL THF solution of
(tBu2bpy)RhH(SiPh3)Cl(PiPr3) (0.100 g, 0.121 mmol) was
cooled to -78 ꢀC. To this solution was added MeLi (0.08 mL
of 1.6 M in Et2O) via syringe, and the reaction mixture was
allowed to stir for 1 h. The solution was allowed to warm to
room temperature and then stirred for an additional 1 h. The
volatile compounds were removed under reduced pressure, and
10 mL of benzene was added to dissolve the resulting solid. The
solution was filtered through Celite, and the volatile material
was removed under vacuum to give a purple solid. Slow
evaporation from a THF solution produced yellow crystals of
13 in 47% yield (0.047 g, 0.097 mmol). NMR spectra and the
X-ray structure are consistent with previously reported data.24
(tBu2bpy)IrH(SiPh3)(Me)PiPr3 (14). A 5 mL THF solution of
(tBu2bpy)IrH(SiPh3)Cl(PiPr3) (0.100 g, 0.110 mmol) was cooled
to -78 ꢀC. To this solution was added MeLi (0.10 mL of 1.6 M in
Et2O) via syringe, and the reaction mixture was allowed to stir
for 1 h. The reaction mixture was allowed to warm to room
temperature and was then stirred for an additional 1 h. The
volatile compounds were then removed under reduced pressure,
and 10 mL of benzene was added to dissolve the product. The
solvent was filtered through Celite, and the volatile material was
removed under vacuum to give a purple solid in 82% yield (0.080
g, 0.090 mmol). 1H NMR (C6D6): δ 8.70 (d, JHH = 6.0 Hz, 1H,
ArH), 8.56 (d, JHH = 6.0 Hz, 1H, ArH), 7.91 (s, 1H, ArH), 7.86
(s, 1H, ArH), 7.65 (d, JHH = 7.5 Hz, 6H, ArH), 7.02 (m, 6H,
ArH), 6.42 (d, JHH = 6.0 Hz, 1H, ArH), 6.18 (d, JHH = 6.0 Hz,
1H, ArH), 2.08 (m, 3H, PCH), 1.06 (s, 9H, CCH3), 1.02 (dd,
(tBu2bpy)IrH(SiPh3)Cl(PPh3) (10). A 5 mL benzene solution
of PPh3 (0.0866 g, 0.330 mmol) was added to a 5 mL solution of
[(tBu2bpy)IrH(SiPh3)(μ-Cl)]2 (0.250 g, 0.165 mmol) in benzene.
The reaction mixture was stirred for 4 h, and the volatile
compounds were removed in vacuo. The resulting orange solid
was dissolved in 5 mL of THF, the reaction mixture was passed
through Celite, and the volatile material was removed under
vacuum. The resulting orange solid was crystallized by vapor
diffusion of pentane into a THF solution to give the product as
1
orange crystals in 88% yield (0.148 g, 0.146 mmol). H NMR
(C6D6): δ 9.06 (d, JHH = 6.0 Hz, 1H, ArH), 7.77 (s, 1H, ArH),
7.61 (d, JHH = 6.4 Hz, 1H, ArH), 7.55-7.34 (ov m, 23H, ArH),
7.31 (d, JHH = 6.4 Hz, 1H, ArH), 7.26 (d, JHH = 6.4 Hz, 1H,
ArH), 7.19 (t, JHH = 2.4 Hz, 6H, ArH), 7.05 (d, JHH = 2.4 Hz,
1H, ArH), 5.90 (d, JHH = 6.4 Hz, 1H, ArH), 1.45 (s, 9H, CCH3),
1.28 (s, 9H, CCH3), -16.87 (d, JHP = 12.8 Hz, 1H, IrH, T1 =
0.547 s). 13C{1H} NMR: δ 160.6, 159.3, 158.3, 150.5, 141.5,
135.6 (JCP = 8.8 Hz), 129.8, 128.0, 126.3 (JCP = 21.1 Hz), 123.2,
122.2, 118.3, 117.3, 35.1, 30.1. 1H, 29Si{1H} HMBC NMR: δ -
9.2 (d, JSiP = 121.7 Hz). 31P{1H} NMR (CD2Cl2): δ -0.36.
Anal. Calcd (%) for C54H55ClIrN2PSi: C, 63.66, H, 5.44, N,
2.75. Found: C, 63.99, H, 5.40, N, 3.04.
(tBu2bpy)Rh(H)2(SiPh3)PiPr3 (11). A 5 mL THF solution of
(tBu2bpy)RhH(SiPh3)Cl(PiPr3) (0.200 g, 0.242 mmol) was
cooled to -78 ꢀC. To this solution was added LiBEt3H
(0.24 mL of 1.0 M in THF) via syringe, and the reaction mixture
was allowed to stir for 1 h. The mixture was allowed to warm to
room temperature and then stirred for an additional 1 h. The
volatile compounds were removed under reduced pressure.
Benzene (15 mL) was added to dissolve the resulting solid.
The solution was filtered through Celite, and the volatile
material was removed in vacuo to give a purple solid. The
resulting purple solid was crystallized by vapor diffusion of
pentane into a THF solution to give the product as purple
crystals in 77% yield (0.147 g, 0.186 mmol). 1H NMR (C6D6): δ
8.68 (d, JHH = 5.6 Hz, 2H, ArH), 7.83 (s, 2H, ArH), 7.76 (d,
J
HH = 7.5 Hz, JHP = 12.0 Hz, 3H, IrCH3), 1.00 (s, 9H, CCH3),
0.83 (m, 9H, PCHCH3), -17.29 (br d, JHP = 17.0 Hz, 1H, IrH).
13C{1H} NMR: δ 156.9, 155.8, 155.7, 148.3, 145.5, 136.2, 136.1,
135.3, 129.2, 126.4, 125.4, 122.9, 122.1, 117.4, 117.2, 38.2, 30.0,
29.4, 18.4 (JCP = 12.5 Hz), -34.1. 1H, 29Si{1H} HMBC NMR: δ
-1.86 (d JSiP = 163.0 Hz). 31P{1H} NMR: δ 6.46. Anal. Calcd
(%) for C46H64IrN2PSi: C, 61.64, H, 7.20, N, 3.13. Found: C,
61.62, H, 7.38, N, 3.10.
(tBu2bpy)IrH(SiPh3)(Ph)PiPr3 (15). A 5 mL THF solution of
(tBu2bpy)IrH(SiPh3)Cl(PiPr3) (0.200 g, 0.218 mmol) was added
to a flask equipped with a stir bar. To this solution was added
PhLi (0.019 g, 0.226 mmol) in 5 mL of THF, and the reaction
solution was allowed to stir for 10 h. The volatile material was
removed under vacuum, and 5 mL of benzene was added to
dissolve the remaining solid. The reaction mixture was filtered
through Celite, and the volatile compounds were removed in
vacuo. A purple-brown solid was isolated in 90% yield (0.189 g,
0.197 mmol). 1H NMR (C6D6): δ 10.07 (d, JHH = 6.0 Hz, 1H,
ArH), 8.89 (d, JHH = 6.0 Hz, 1H, ArH), 8.15 (d, JHH = 7.0 Hz,
JHH = 6.5 Hz, 6H, ArH), 7.15 (ov m, 9H, ArH), 6.40 (d, JHH =
6.5 Hz, 2H, ArH), 1.93 (br d, JHH = 6.8 Hz, 3H, PCH), 1.19 (s,
18H, CCH3), 0.95 (m, 18H, PCHCH3), -16.06 (dd, JHP = 21.0
Hz, JRhH = 13.5 Hz, 2H, RhH). 13C{1H} NMR: δ 156.4, 154.3,
153.2, 136.2, 135.7, 129.4, 126.4, 125.5, 120.9, 117.0, 30.0, 26.3
1
(JCP = 7.0 Hz), 19.6. H, 29Si{1H} HMBC NMR: δ 24.4 (dd,
JSiP = 173.0 Hz, JSiRh = 11.4 Hz). 31P{1H} NMR: δ 44.9 (d
JPRh = 91.0 Hz). Anal. Calcd (%) for C45H62N2PRhSi: C,
68.16, H, 7.88, N, 3.53. Found: C, 68.06, H, 8.00, N, 3.64.
(tBu2bpy)Ir(H)2(SiPh3)(PiPr3) (12). A 5 mL THF solution of
(tBu2bpy)IrH(SiPh3)Cl(PiPr3) (0.100 g, 0.110 mmol) was cooled
to -78 ꢀC. To this solution was added LiBEt3H (0.15 mL of 1.0
M in THF) via syringe, and the reaction mixture was allowed to
stir for 1 h. The mixture was allowed to warm to room
temperature and then stirred for an additional 1 h. The volatile
compounds were then removed under reduced pressure, and
15 mL of benzene was added to dissolve the product. The
resulting solution was filtered through Celite, and the volatile
components were removed under vacuum. The resulting purple
solid was crystallized by vapor diffusion of pentane into a
THF solution to give purple crystals in 78% yield (0.075 g,
2H, ArH), 7.67 (s, 1H, ArH), 7.65 (s, 1H, ArH), 7.52 (d, JHH
=
7.0 Hz, 6H, ArH), 7.09 (br d, 9H, ArH), 6.93 (t, JHH = 7.0 Hz,
2H, ArH), 6.63 (ov m, 2H, ArH), 6.22 (d, JHH = 6.0 Hz, 1H,
ArH), 2.07 (m, 3H, PCH), 1.09 (m, 18H, PCHCH3), 0.94 (s, 9H,
CCH3), 0.57 (q, 9H, PCHCH3), -17.48 (d, JHP = 16.0 Hz, 1H,
IrH). 13C{1H} NMR: δ 157.2, 156.3, 155.7, 155.4, 153.9, 146.9,
141.3, 136.5, 128.6, 128.1, 127.7, 126.2, 125.1, 122.4, 122.1,
121.7, 120.5, 118.6, 118.0, 29.9, 29.7, 21.6 (JCP = 18.0 Hz),
1
20.6 (JCP = 13.0 Hz). H, 29Si{1H} HMBC NMR: δ -3.42.
31P{1H} NMR: δ 19.36. Anal. Calcd (%) for C51H62IrN2PSi:
C64.19, H, 6.55, N, 2.94. Found: C, 63.84, H, 6.48, N, 3.14.
[(tBu2bpy)Rh(SiPh3)(μ-H)]2[B(C6F5)4]2 (16). A 5 mL fluoro-
benzene solution of [(tBu2bpy)RhH(SiPh3)(μ-Cl)]2 (0.132 g,
0.198 mmol) was added to a flask equipped with a stir bar. To
this solution was added LiB(C6F5)4(Et2O)2 (0.165 g, 0.198
mmol), and the reaction mixture was allowed to stir for 2 h.
The mixture was filtered through Celite, and the volatile ma-
terial was removed under vacuum to give a maroon solid in 90%
yield (0.237 g, 0.178 mmol). 1H NMR (CD2Cl2): δ 7.92 (d,
1
0.085 mmol). H NMR (C6D6): δ 8.96 (d, JHH = 5.6 Hz, 2H,
ArH), 7.78 (d, JHH = 7.6 Hz, 6H, ArH), 7.57 (s, 2H, ArH), 7.06
(ov m, 9H, ArH), 6.30 (d, JHH = 5.6 Hz, 2H, ArH), 1.99
(br d, JHH = 6.8 Hz, 3H, PCH), 1.03 (s, 18H, CCH3), 0.96 (q,
JHH = 6.8 Hz, 18H, PCHCH3), -18.93 (d, JHP = 16.8 Hz,
2H, IrH). 13C{1H} NMR: δ 155.3, 154.9, 154.8, 144.5, 136.2,
127.9, 126.4, 125.5, 121.8, 117.8, 34.1, 27.6 (JCP = 16.0 Hz),
1
19.4. H, 29Si{1H} HMBC NMR: δ 6.65 (d, JSiP = 128.0 Hz,
J
Hz, 18H, ArH), 7.24 (d, JHH = 6.0 Hz, 4H, ArH), 7.00 (t, JHH
HH = 6.0 Hz, 4H, ArH), 7.81 (s, 4H, ArH), 7.35 (d, JHH = 7.0
=
JSiH = 4.5 Hz). 31P{1H} NMR: δ 27.54. Anal. Calcd (%) for
C45H62IrN2PSi: C, 61.26, H, 7.08, N, 3.18. Found: C, 61.21, H,
7.14, N, 3.04.
7.0 Hz, 12H, ArH), 1.47 (s, 36H, CCH3), -22.73 (t, JRhH = 33.5
Hz, 2H, RhH). 13C{1H} NMR: δ 170.9, 154.2, 153.7, 147.2 (br),

Article
Organometallics, Vol. 28, No. 17, 2009 5081
137.2 (br), 135.9, 135.5, 135.3 (br), 131.6, 131.2, 128.3 (br),
F
NMR: δ -131.4 (br s, 16F), -162.3 (br s, 8F), -166.3 (br s,
16F). Anal. Calcd (%) for C120H80B2F40N4Rh2Si2: C, 54.98, H,
3.08, N, 2.14. Found: C, 54.71, H, 3.20, N, 2.14.
were made using SADABS. Structures were solved by direct
methods and expanded using Fourier techniques. All calcula-
tions were performed using the SHELXTL crystallographic
package. All non-hydrogen atoms were refined anisotropically
unless otherwise stated.
127.8, 124.7, 120.1, 29.7. 1H, 29Si{1H} HMBC NMR: δ 24.1. 19
[(tBu2bpy)Ir(SiPh3)(μ-H)]2[B(C6F5)4]2 (17). A 5 mL CH2Cl2
solution of [(tBu2bpy)IrH(SiPh3)(μ-Cl)]2 (0.150 g, 0.199 mmol)
was added to a flask equipped with a stir bar. To this solution
was added LiB(C6F5)4(Et2O)2 (0.166 g, 0.199 mmol), and the
reaction mixture was allowed to stir for 2 h. The solution was
filtered through Celite, and the volatile compounds were re-
moved in vacuo to give an orange solid. The resulting orange
solid was dissolved in 1 mL of CH2Cl2, and pentane was allowed
to vapor-diffuse into the solution. Orange crystals of the pro-
duct were isolated in 92% yield (0.256 g, 0.178 mmol). 1H NMR
(CD2Cl2): δ 8.28 (d, JHH = 6.0 Hz, 4H, ArH), 7.84 (s, 4H, ArH),
7.25 (m, 18H, ArH), 7.13 (d, JHH = 6.0 Hz, 4H, ArH), 6.93 (t,
JHH = 7.0 Hz, 12H, ArH), 1.43 (s, 36H, CCH3), -22.51 (s, 2H,
IrH). 13C{1H} NMR: δ 166.7, 154.9, 154.4, 149.1 (br), 147.1 (br),
137.2 (br), 135.4, 131.6, 131.0, 127.9, 125.3, 120.3, 29.7. 1H,
29Si{1H} HMBC NMR: δ -21.0. 19F NMR: δ -132.3 (br s,
16F), -162.7 (br s, 8F), -166.7 (br s, 16F). Anal. Calcd (%) for
For 7: Crystals were grown from vapor diffusion of pentane
into THF at 25 ꢀC.
For 8: Crystals were grown from vapor diffusion of pentane
into THF at 25 ꢀC.
For 11: Crystals were grown from slow evaporation of THF
at 25 ꢀC.
For 12: Crystals were grown from slow evaporation of THF
at 25 ꢀC.
For 14: Crystals were grown from vapor diffusion of pentane
into THF at -30 ꢀC.
For 17: Crystals were grown from vapor diffusion of pentane
into CH2Cl2 at 25 ꢀC.
Acknowledgment. This work is supported by the Di-
rector, Office of Energy Research, Office of Basic Energy
Sciences, Chemical Sciences Division, of the U.S. Depart-
ment of Energy under Contract DE-AC02-76SF0098. We
thank Dr. Rudi Nunlist for NMR spectroscopy assis-
tance and Dr. Frederick Hollander and Dr. Antonio
diPasquale for X-ray crystallography assistance.
C
120H80B2F40Ir2N4Si2: C, 51.47, H, 2.88, N, 2.00. Found: C,
51.17, H, 2.92, N, 2.00.
X-ray Structure Determinations. The X-ray analyses of com-
pounds 7, 8, 11, 12, 14, and 17 were carried out at the UC
Berkeley CHEXRAY crystallographic facility. Measurements
were made with a Bruker SMART CCD area detector with
Supporting Information Available: Text describing complete
experimental details for solutions of the X-ray structures, and
structural data for 7, 8, 11, 12, 14, and 17. This material is
available free of charge via the Internet at http://pubs.acs.org.
˚
graphite-monochromated Mo Ka radiation (λ = 0.71073 A).
Data were integrated by the program SAINT and analyzed for
agreement using XPREP. Empirical absorption corrections