Silyl derivatives of [Bis(8-quinolyl)methylsilyl]iridium(III) complexes: Catalytic redistribution of arylsilanes and dehydrogenative arene silylation

Article abstract of DOI:10.1021/om700494q

The reactive complex (NSiN)Ir(H)(OTf)(coe) (1; NSiN = bis(8-quinolyl) methylsilyl, coe = cyclooctene) was generated by reaction of the previously reported (NSiN)Ir(H)Cl(coe) with 1 equiv of AgOTf. Addition of Ph₃SiH to 1 in benzene led to Si-H bond activation and octane elimination with formation of the α-Ph-migrated, 16-electron product (NSiN)IrPh(SiPh ₂OTf) (2). The ²⁹Si{¹H} NMR resonance of 2 at δ 54.0 indicates iridium silyl character, and X-ray crystallography reveals the presence of a highly distorted triflatosilyl group. In acetonitrile, 1 reacts with various silanes to give stable, cationic Ir(III) complexes of the type [(NSiN)IrSiR₃(NCMe)₂][OTf] (R = OSiMe₃, Et, Ph) or [(NSiN)Ir{SiH(R)Ph)(NCMe)₂][OTf] (R = H, Ph) in good yields. Complex 1 is an active catalyst for arylsilane redistribution and for the dehydrogenative silylation of arenes. The cationic, THF complex [(NSiN)Ir(H)(coe)(THF)] [B(C₆F₅)₄] (10), a product of the reaction of 1 with 1 equiv of Li(Et₂O) ₃[B(C₆F₅)₄] in THF, is a slower catalyst for silane redistribution and dehydrogenative arene silylation. A series of new iridium phosphine complexes were prepared, including (NSiN)Ir(H)Cl(PMe₃) (13), [(κ²-NSiN)Ir(H)(PMe ₃)₃][Cl] (14), and (κ¹-NSiN)Ir(H)(Me) (PMe₃)₃ (15). Treatment of the previously prepared (NSiN)Ir(H)Cl(PPh₃) with 1 equiv of LiBEt₃H afforded the dihydride complex (NSiN)IrH₂(PPh₃) (11), which features a hydride ligand in a coordination site trans to the NSiN silyl group. The triflate complex (NSiN)Ir(H)(OTf)(PPh₃) (16) was obtained by reaction of (NSiN)Ir(H)Cl(PPh₃) with 1 equiv of AgOTf in dichloromethane or by reaction of 1 with 1 equiv of PPh₃ in dichloromethane.

Full text of DOI:10.1021/om700494q

Organometallics 2007, 26, 5557-5568
5557
Silyl Derivatives of [Bis(8-quinolyl)methylsilyl]iridium(III)
Complexes: Catalytic Redistribution of Arylsilanes and
Dehydrogenative Arene Silylation
Preeyanuch Sangtrirutnugul and T. Don Tilley*
Department of Chemistry and Center for New Directions in Organic Synthesis (CNDOS),
UniVersity of California, Berkeley, Berkeley, California 94720
ReceiVed May 17, 2007
The reactive complex (NSiN)Ir(H)(OTf)(coe) (1; NSiN ) bis(8-quinolyl)methylsilyl, coe ) cyclooctene)
was generated by reaction of the previously reported (NSiN)Ir(H)Cl(coe) with 1 equiv of AgOTf. Addition
of Ph3SiH to 1 in benzene led to Si-H bond activation and octane elimination with formation of the
R-Ph-migrated, 16-electron product (NSiN)IrPh(SiPh2OTf) (2). The 29Si{1H} NMR resonance of 2 at δ
54.0 indicates iridium silyl character, and X-ray crystallography reveals the presence of a highly distorted
triflatosilyl group. In acetonitrile, 1 reacts with various silanes to give stable, cationic Ir(III) complexes
of the type [(NSiN)IrSiR3(NCMe)2][OTf] (R ) OSiMe3, Et, Ph) or [(NSiN)Ir{SiH(R)Ph}(NCMe)2][OTf]
(R ) H, Ph) in good yields. Complex 1 is an active catalyst for arylsilane redistribution and for the
dehydrogenative silylation of arenes. The cationic, THF complex [(NSiN)Ir(H)(coe)(THF)][B(C6F5)4]
(10), a product of the reaction of 1 with 1 equiv of Li(Et2O)3[B(C6F5)4] in THF, is a slower catalyst for
silane redistribution and dehydrogenative arene silylation. A series of new iridium phosphine complexes
were prepared, including (NSiN)Ir(H)Cl(PMe3) (13), [(κ2-NSiN)Ir(H)(PMe3)3][Cl] (14), and (κ1-NSiN)-
Ir(H)(Me)(PMe3)3 (15). Treatment of the previously prepared (NSiN)Ir(H)Cl(PPh3) with 1 equiv of LiBEt3H
afforded the dihydride complex (NSiN)IrH2(PPh3) (11), which features a hydride ligand in a coordination
site trans to the NSiN silyl group. The triflate complex (NSiN)Ir(H)(OTf)(PPh3) (16) was obtained by
reaction of (NSiN)Ir(H)Cl(PPh3) with 1 equiv of AgOTf in dichloromethane or by reaction of 1 with 1
equiv of PPh3 in dichloromethane.
processes.5 On the basis of these considerations, we became
interested in the coordination chemistry of the tridentate bis-
(8-quinolyl)methylsilyl ligand (NSiN) and the reactivity of its
complexes. Given the geometry and rigidity of the ligand
structure, facial coordination modes are expected to be favored.
Introduction
Complexes containing multidentate ligands have attracted
considerable interest for their ability to mediate new transforma-
tions. These ligands lend stability to their complexes and provide
a rigid coordination geometry with “enforced” chemical proper-
ties. Notable examples of such complexes include (PCP)IrH2
(PCP ) 2,6-(tBu2PCH2)2C6H3),1 which catalytically dehydro-
genates alkanes, and the pincer-based complex (NCN)NiBr
(NCN ) 2,6-(Me2NCH2)2C6H3),2 which is a catalyst for addition
of CCl4 across alkenes.
Despite considerable recent activity in the development and
exploration of multidentate ligands, examples of such ligand
frameworks containing silicon donors are rare.3 Since silicon
possesses strong electron-donating and trans-labilizing proper-
ties,4 a supporting ligand containing silicon should be effective
at stabilizing coordinatively unsaturated complexes. In addition,
hard, nitrogen-based ligands combined with soft late transition
metals are known to promote a number of bond activation
The syntheses of bis(8-quinolyl)methylsilane, and rhodium
complexes derived therefrom, were recently reported.6 One
theme that emerged from this work is that coordinatively
unsaturated (NSiN)Rh(III) derivatives are readily accessible, and
along these lines the 16-electron complexes [(NSiN)Rh(H)-
(PPh3)][B(C6F5)]4 and (NSiN)Rh(CH2Ph)2 were isolated. In
these complexes, the silyl group appears to significantly stabilize
coordinatively unsaturated, square-pyramidal structures, and the
reactivity of such species seems to be somewhat limited. Further
investigations of chemistry associated with (NSiN)M fragments
has included examinations of iridium derivatives, especially
since iridium can more readily access higher oxidation states
and is known to facilitate unusual bond activations in several
catalytic systems.1,7 Previous work involved synthesis and study
of the chemically robust, 18-electron complex (NSiN)Ir-
(H)Cl(coe).8 This paper describes investigations of the more
* Corresponding author. E-mail: tdtilley@berkeley.edu.
(1) Jensen, C. M. Chem. Commun. 1999, 24, 2443.
(2) van de Kuil, L. A.; Grove, D. M.; Gossage, R. A.; Zwikker, J. W.;
Jenneskens, L. W.; Drenth, W.; van Koten, G. Organometallics 1997, 16,
4985.
(3) (a) Stobart, S. R.; Brost, R. D.; Bruce, G. C.; Joslin, F. L.
Organometallics 1997, 16, 5669. (b) Lee, Y.-J.; Bae, J.-Y.; Kim, S.-J.; Ko,
J.; Choi, M.-G.; Kang, S. O. Organometallics 2000, 19, 5546. (c) Tobita,
H.; Hasegawa, K.; Minglana, J. J. G.; Luh, L.-S.; Okazaki, M.; Ogino, H.
Organometallics 1999, 18, 2058. (d) Minato, M.; Nishiuchi, J.; Kakeya,
M.; Matsumoto, T.; Yamaguchi, Y.; Ito, T. Dalton Trans. 2003, 483.
(4) (a) Chatt, J.; Eaborn, C.; Ibekwe, S. J. Chem. Soc., Chem. Commun.
1966, 700. (b) Haszeldine, R. N.; Parish, R. V.; Setchfield, J. H. J.
Organomet. Chem. 1973, 57, 279.
(5) (a) Slugovc, C.; Padilla-Martinez, I.; Sirol, S.; Carmona, E. Coord.
Chem. ReV. 2001, 213, 129. (b) Peters, J. C.; Harkins, S. B. Organometallics
2002, 21, 1753. (c) Rodriguez, P.; Diaz-Requejo, M. M.; Belderrain, T. R.;
Trofimenko, S.; Nicasion, M. C.; Perez, P. J. Organometallics 2004, 9,
2162. (d) Graham, W. A. G.; Ghosh, C. K. J. Am. Chem. Soc. 1987, 109,
4726. (e) Holtcamp, M. W.; Henling, L. M.; Day, M. W.; Labinger, J. A.;
Bercaw, J. E. Inorg. Chim. Acta 1998, 270, 467.
(6) Sangtrirutnugul, P.; Stradiotto, M.; Tilley, T. D. Organometallics
2006, 25, 1607.
10.1021/om700494q CCC: $37.00 © 2007 American Chemical Society
Publication on Web 10/06/2007

5558 Organometallics, Vol. 26, No. 23, 2007
Sangtrirutnugul and Tilley
reactive triflate analogue, including its use in the catalytic,
dehydrogenative silylation of arenes.
Results and Discussion
Synthesis and Characterization of (NSiN)Ir(H)(OTf)(coe)
(1). To access a more reactive, monomeric (NSiN)Ir complex,
(NSiN)Ir(H)Cl(coe) was treated with 1.0 equiv of AgOTf in
dichloromethane, to produce the corresponding triflate complex
(NSiN)Ir(H)(OTf)(coe) (1) as an analytically pure, off-white
solid in 93% yield (eq 1). The 1H NMR spectrum of 1 contains
two sets of quinolyl protons, suggesting Cs symmetry. Ad-
ditionally, the 1H NMR signals assigned to the hydride (δ
-14.7) and cyclooctene (δ 2.07-1.10 and 0.82) ligands are
broadened in dichloromethane-d2 but appear as sharp resonances
in benzene-d6, suggesting an exchange process involving
dissociation/association of the triflate anion. The IR spectrum
of 1 displays a distinctive band at 2161 cm-1, corresponding to
a hydride ligand. On the basis of the NMR and IR data, 1 is
believed to possess an octahedral geometry with an inner-sphere
triflate weakly bonded to iridium and trans to the strongly trans-
labilizing silyl group.
Figure 1. ORTEP diagram of the 16-electron complex 2 with
thermal ellipsoids shown at the 50% probability level. Hydrogen
atoms are omitted for clarity. Selected bond lengths (Å): Ir-Si2
) 2.289(2), Si2-O1 ) 1.844(5). Selected bond angles (deg): C20-
Ir-Si2 ) 93.1(2), C26-Si2-C32 ) 106.4(3).
OTf) (2.317(2) Å)11 and (TFB)(PiPr3)IrH2(SiPh2OTf) (2.337-
(2) Å, TFB ) tetrafluorobenzobarrelene),12 but longer than the
iridium-silicon bond length in the silylene complex [PhB(CH2-
PPh2)3]IrH2(SiMes2) (2.260(3) Å).13 However, the 29Si{1H}
NMR signal for the triflatosilyl group of 2 appears at δ 54.0,
which is characteristic for a silyl ligand and an sp3 silicon
center.14
Reactions of 1 with Silanes. Treatment of 1 with Ph3SiH in
benzene at room temperature resulted in Si-H bond activation,
release of cyclooctane, and R-phenyl migration to produce the
16-electron complex (NSiN)IrPh(SiPh2OTf) (2, eq 2). This
process is related to that found for Cp*(PMe3)IrMe(OTf), which
reacts with Ph3SiH to give Cp*(PMe3)IrPh(SiPh2OTf).9 For both
reactions, it is likely that a 16-electron Ir-SiPh3 intermediate
rearranges to a phenyl silylene complex of the type (Ph)Ird
SiPh2. This latter, second intermediate then adds triflate to
produce the final product.
Given the isoelectronic relationship between NSiN and the
well-known Cp* ligand, it is of interest to compare reactivities
of the (NSiN)Ir and Cp*Ir fragments. Reaction of the 18-electron
complex Cp*(PMe3)IrPh(SiPh2OTf) with 1 equiv of Li(Et2O)3-
[B(C6F5)4] in dichloromethane-d2 leads to intramolecular C-H
activation of the o-hydrogen of the diphenyltriflatosilyl group
to afford the four-membered Ir(V) metallacycle [Cp*(PMe3)-
Ir(η2-SiPh2C6H4)(H)][B(C6F5)4].15 In contrast, treatment of 2
with Li(Et2O)3[B(C6F5)4] in dichloromethane-d2 resulted in a
1
mixture of products based on H NMR spectroscopy, and no
iridium hydride species were observed.
Addition of (Me3SiO)3SiH to 1 in benzene resulted in the
formation of 3, obtained as an orange microcrystalline solid in
48% yield from slow evaporation of benzene at room temper-
1
ature (Scheme 1). The H NMR spectrum of 3 in benzene-d6
exhibits one set of quinolyl protons, indicating mirror symmetry
for the molecule, and a single resonance is observed for the
-OSiMe3 groups at δ 0.023. Consistently, there is a distinct
29Si{1H} NMR signal at δ 4.1 assignable to the -OSiMe3 group
An X-ray crystal structure determination of 2 reveals a square-
pyramidal geometry about the iridium center with the silyl group
in an apical position (Figure 1). The Si2-O1 bond distance of
1.844(5) Å is comparable to the median Si-O bond length for
complexes containing a SiR2(OTf) group (1.842 Å).10 In
addition, the sum of the angles around this silicon atom,
excluding the triflate substituent, approaches 360° (ca. 350.5°),
which is suggestive of a trigonal-planar coordination environ-
ment about Si and silylene character. The Ir-Si2 bond distance
for the diphenyltriflatosilyl group of 2 (2.289(2) Å) is shorter
than those of similar complexes including Cp*(PMe3)IrPh(SiPh2-
1
29
(by a 2D H,29Si HMBC NMR experiment). However, the
-
Si{1H} NMR shift corresponding to -Si(OSiMe3)3 could not
be detected, by 2D 1H,29Si HMBC or by direct detection
1
experiments. Variable-temperature H NMR experiments re-
vealed that the -OSiMe3 peak becomes broader at lower
temperature, but no decoalescence was observed at temperatures
as low as -90 °C. The elemental analysis of 3 is consistent
with a compound having the empirical formula (NSiN)Ir[Si-
(OSiMe3)3](OTf). Possible structures of 3 include a five-
(7) (a) Go¨ttker-Schnetmann, I.; White, P.; Brookhart, M. J. Am. Chem.
Soc. 2004, 126, 1804. (b) Goldman, A. S.; Roy, A. H.; Huang, Z.; Ahuja,
R.; Schinski, W.; Brookhart, M. Science 2006, 312, 257. (c) Gupta, M.;
Hagen, C.; Kaska, W. C.; Cramer, R. E.; Jensen, C. M. Chem. Commun.
1996, 2083.
(8) Stradiotto, M.; Fujdala, K.; Tilley, T. D. Chem. Commun. 2001, 13,
1200.
(11) Klei, S. R.; Tilley, T. D.; Bergman, R. G. Organometallics 2002,
21, 3376.
(12) Chen, W.; Edwards, A. J.; Esteruelas, M. A.; Lahoz, F. J.; Oliva´n,
M.; Oro, L. A. Organometallics 1996, 15, 2185.
(13) Peters, J. C.; Feldman, J. D.; Tilley, T. D. J. Am. Chem. Soc. 1999,
121, 9871.
(9) Burger, P.; Bergman, R. G. J. Am. Chem. Soc. 1993, 115, 10462.
(10) The Si-OTf median bond length was obtained from the Cambridge
Structure Database.
(14) Corey, J. Y.; Braddock-Wilking, J. Chem. ReV. 1999, 99, 175.
(15) Klei, S. R.; Tilley, T. D.; Bergman, R. G. J. Am. Chem. Soc. 2000,
122, 1816.

Silyl DeriVatiVes of [Bis(8-quinolyl)methylsilyl]iridium(III) Complexes
Organometallics, Vol. 26, No. 23, 2007 5559
Scheme 1
type of bond activation appears to occur in the reaction of Cp*-
(PMe3)Ir(Me)(OTf) with Ph2SiH2 to afford the hydride-migration
product Cp*(PMe3)Ir(H)(SiPh2OTf) via CH4 elimination.9 A
similar R-H migration results from reaction of [PhB(CH2PPh2)3]-
Ir(H)(η3-C8H13) with Mes2SiH2, to give the iridium silylene
complex [PhB(CH2PPh2)3]IrH2(SiMes2).13 Unfortunately, related
reactions of 1 with Ph2SiH2 and PhSiH3 in various solvents (e.g.,
benzene and THF) at room temperature or at 70 °C resulted in
intractable mixtures of products. Analysis of the reaction
1
mixtures by H NMR spectroscopy revealed the presence of
iridium hydride complexes. Much cleaner reactions were
observed with acetonitrile as the solvent, and this allowed
synthesis of the Ir(III) complexes 7 and 8 (eq 4).
coordinate monomeric complex and a related six-coordinate
geometry with an -OSiMe3 group bonded to iridium via the
oxygen atom. Additionally, 3 may possess oligomeric structures
involving bridging -Si(OSiMe3)3 groups. A dynamic process
involving rapid dissociation and association of the triflate group
would explain the apparent equivalency of the quinolyl protons
1
(by H NMR spectroscopy).
Synthesis of 18-Electron Complexes [(NSiN)IrSiR3(NCMe)2]-
[OTf]. Heating an acetonitrile solution of 3 at 70 °C for 12 h
quantitatively generated the nitrile complex [(NSiN)IrSi-
(OSiMe3)3(NCMe)2][OTf] (4), which was characterized by
multinuclear NMR spectroscopy and combustion analysis.
Formation of the acetonitrile complex 4 prompted attempts to
trap the proposed triflate intermediate (NSiN)Ir(SiPh3)(OTf)
(Vide supra) with acetonitrile. Thus, reaction of 1 with Ph3SiH
in acetonitrile resulted in release of cyclooctane and formation
of a new compound, 5. Combustion analysis and NMR data
identify 5 as the 18-electron complex [(NSiN)IrSiPh3(NCMe)2]-
[OTf] (eq 3). In addition, 1H NMR spectroscopy reveals that 5
was generated from heating a benzene-d6 solution of 2 with
excess acetonitrile (ca. 10 equiv) at 60 °C for 1 day, indicating
that 2 is in equilibrium with the 16-electron intermediate (NSiN)-
Ir(SiPh3)(OTf) (eq 2). X-ray quality crystals of 5 were obtained
by layering diethyl ether onto a dichloromethane solution of
the complex at room temperature. Complex 5 possesses a
distorted octahedral geometry and an outer-sphere triflate anion.
The Ir-NCMe bond trans to Si is approximately 0.20 Å longer
than that trans to the quinolyl N atom. Additional Si-H bond
1
1
The H NMR spectrum of 7 (acetonitrile-d3) contains a H
NMR signal at δ 4.33 assigned to the silicon-bound hydrogen,
and the 29Si{1H} chemical shift for 7 appears at δ -25 (1JSiH
) 173 Hz). The 1H NMR spectrum of 8 (acetonitrile-d3) displays
two diastereotopic protons for the phenylsilyl group, observed
as doublets at δ 3.39 (2JHH′ ) 6.0 Hz, JSiH ) 171 Hz) and
1
3.84 (2JHH′ ) 6.0 Hz, 1JSiH ) 169 Hz). The large Si-H coupling
1
constants for 7 and 8 are within the JSiH values reported for
free silanes (150-200 Hz) and, hence, suggest no R-H agostic
interaction between an SiH group and the iridium center.14
Heating dichloromethane-d2 solutions of 7 and 8 at 50 °C over
1
1 day resulted in unidentified products (by H NMR spectros-
copy).
Addition of 1 equiv of cyclooctene to a reaction mixture of
1 and Ph2SiH2 (1 equiv) in benzene-d6 at ambient temperature
allowed observation of 2 and the new complex (NSiN)IrPh-
[SiPh(H)OTf] (9; 30% formation using a ferrocene standard)
after 1 h at room temperature, as identified by H, 19F, and
-
1
29
activations were found to give complexes analogous to 5, as
shown in eq 3. Complex 1 oxidatively adds the Si-H bonds of
(Me3SiO)3SiH and Et3SiH in acetonitrile at ambient temperature
to produce the corresponding products 4 and 6, respectively.
Note that the related nitrile adduct [Cp*(PMe3)RhSiPh3(NCMe)]-
[BAr′4] was reported to undergo intramolecular C-C bond
activation to afford the isocyanide complex [Cp*(PMe3)RhMe-
(CNSiPh3)][BAr′4] at room temperature.16 In contrast, no
reaction was observed for a dichloromethane-d2 solution of 5
either at ambient temperature or at 60 °C over 2 days.
Figure 2. ORTEP diagram of complex 5 with thermal ellipsoids
shown at the 50% probability level. Hydrogen atoms, one of the
phenyl rings on Si2, and a OTf counterion are omitted for clarity.
Selected bond lengths (Å): Ir-Si2 ) 2.369(1), Ir-N3 ) 1.990-
(3), Ir-N4 ) 2.190(3). Selected bond angles (deg): Si2-Ir-N3
) 92.24(8), Si1-Ir-N4 ) 171.89(7).
It was also of interest to investigate the possible role of R-H
migration in the chemistry of (NSiN)Ir silyl complexes. This
(16) Taw, F. L.; White, P. S.; Bergman, R. G.; Brookhart, M. J. Am.
Chem. Soc. 2002, 124, 4192.

5560 Organometallics, Vol. 26, No. 23, 2007
Sangtrirutnugul and Tilley
Table 1. Results of Catalytic Redistributions Using Catalyst
1 (10 mol %) in the Presence of 1 equiv of Cyclooctene at 85
°C in Benzene-d6 (reaction time of 24 h)
undergo R-Ph migration to produce the observed Ir(III) species
9. An Si-H oxidative addition to 9, followed by Si-C bond
reductive elimination, affords Ph3SiH and the 16-electron
iridium hydride species (NSiN)IrH[SiPh(H)OTf]. An R-H
migration from iridium to silicon and Si-H bond activation of
Ph2SiH2 may result in an Ir(V) disilylhydride, which could
reductively eliminate PhSiH3 and reproduce A. Phenylsilane may
re-enter the catalytic cycle as a starting material to be converted
to redistribution products (Ph3SiH, Ph2SiH2, and SiH4). This
repeated silane redistribution may account for the fact that
PhSiH3 is undetected (by 1H NMR spectroscopy and GC/MS).
entry
1
silane
products (% yield)a
Ph2SiH2
Ph3SiH (24%), Ph2SiH2 (40%),
b
PhSiH3 (trace), SiH4
2
3
4
5
6
PhSiH3
Ph2SiH2 (11%), PhSiH3 (50%),
b
Ph3SiH (<3%), SiH4
c
MesSiH3
Mes2SiH2 (25%), MesSiH3 (21%),
b
Mes3SiH (5%), SiH4
(p-tol)SiH3
(C6F5)SiH3
Et2SiH2
(p-tol)2SiH2 (12%), (p-tol)SiH3 (44%),
b
(p-tol)3SiH (<3%), SiH4
(C6F5)2SiH2 (15%), (C6F5)SiH3 (32%),
1
Since complex 2 is observed by H NMR spectroscopy at
b
(C6F5)3SiH (14%), SiH4
the end of the catalytic reaction with Ph2SiH2 as a substrate,
formation of 2 is believed to arise from addition of the
redistribution product, Ph3SiH, to the intermediate A, as shown
in Scheme 3. At elevated temperature, 2 may rearrange to
(NSiN)Ir(SiPh3)(OTf), which is expected to react with Ph2SiH2
to produce A and Ph3SiH. Consistent with this, it was found
that 2 is a catalyst for the arylsilane redistribution of Ph2SiH2
to Ph3SiH (benzene-d6, 85 °C, 24 h, 10 mol % 2).
To investigate the role of cyclooctene as a promoter in the
catalytic redistribution, it was removed from the reaction system.
By 1H NMR spectroscopy, only about 30% of the Ph2SiH2 was
consumed, compared to 60% consumption of Ph2SiH2 in the
presence of cyclooctene after 24 h (Table 1). While the exact
role of cyclooctene in the catalysis is still unclear, its presence
apparently speeds up the reaction rate, possibly through
stabilization of the reactive, 16-electron species A and B.
Complex 1 as a Catalyst for Dehydrogenative Arene
Silylation. The chemistry described above established the utility
of (NSiN)Ir fragments in Si-H bond activation and Si-C bond
formation. Thus, it seemed possible to observe dehydrogenative
couplings of silanes with hydrocarbons, given the ability of
(NSiN)Ir species to activate C-H bonds.
N/A
a Based on 1H NMR spectroscopy with a ferrocene standard and GC/
b
c
MS. Amount of SiH4 was not determined. Mes ) 2,4,6-trimethylphenyl.
Si{1H} NMR spectroscopy. The 1H NMR signal at δ 5.49 (1JSiH
) 176 Hz) is assigned to the silyl proton of 9, for which a 2D
1H,29Si HMBC experiment revealed a correlation between this
1H NMR resonance and a 29Si{1H} resonance at δ -24.5.
However, attempts to isolate 9 were unsuccessful, as the product
1
mixtures converted to Ph3SiH (ca. 60% by H NMR spectros-
copy), SiH4 (trace, δ 3.09), and 2 after 1 day at room
temperature (Scheme 2). A GC/MS analysis of the Ph3SiH did
not reveal the presence of deuterated phenyl groups, confirming
that silane redistribution of Ph2SiH2, rather than benzene
activation, had occurred. Interestingly, while complex mixtures
in benzene-d6 were obtained in the absence of cyclooctene (Vide
supra), in the presence of cyclooctene, the silane redistribution
products Ph3SiH and SiH4 formed cleanly.
Complex 1 as a Catalyst for Arylsilane Redistribution.
The activity of 1 as a silane redistribution catalyst was examined
further with reactions of 10 mol % of 1 and cyclooctene with
a variety of primary and secondary silanes in benzene-d6 at 85
°C for 24 h. The results obtained are summarized in Table 1.
The product yields relative to silane consumption are consistent
with an arylsilane redistribution process. For example, con-
sumption of 1 equiv of Ph2SiH2 resulted in production of 2/3
equiv of Ph3SiH. Similarly, 1 equiv of a primary aryl silane
ArSiH3 is expected to yield 0.5 equiv of Ar2SiH2 and SiH4
products. However, since Ar2SiH2 undergoes further silane
redistribution to the tertiary silane Ar3SiH, lower yields of the
secondary silane products were observed. This redistribution
chemistry appears to be limited to aryl and hydrogen substituents
at silicon, since the non-aryl silane Et2SiH2 did not give
redistribution products under the same reaction conditions.
A plausible mechanism for silane redistribution, based on
R-migration chemistry, is proposed in Scheme 3. The Si-H
bond oxidative addition of Ph2SiH2 to 1 generates the 16-
electron intermediate (NSiN)Ir(SiPh2H)(OTf) (A), which may
A benzene-d6 solution of Ph3SiH, the hydrogen-acceptor tert-
butylethylene (TBE), and 10 mol % of 1 was heated to 120 °C
for 24 h. These conditions resulted in consumption of 67% of
the Ph3SiH and formation of Ph SiC D along with Ph SiCHd
3
6
5
1
3
CHtBu as a minor product, based on H NMR spectroscopy
and GC/MS analysis (Table 2). The scope of this dehydroge-
native arene silylation catalysis was then examined with other
arene substrates including trifluoromethylbenzene and chlo-
robenzene. Under the same catalytic conditions, higher conver-
sions were obtained for the latter substrates, but the selectivity
was lower. The hydrogen acceptor is essential for the catalytic
conversions, as only trace amounts of Ph3SiC6D5 were detected
in the absence of TBE after 24 h at 120 °C in benzene-d6.
By replacing TBE with norbornene as the hydrogen acceptor,
fewer coproducts and none of the reductive alkene hydrosily-
lation products were observed under the same reaction condi-
tions (entries 4-7; Table 2). The best result was obtained from
Scheme 2

Silyl DeriVatiVes of [Bis(8-quinolyl)methylsilyl]iridium(III) Complexes
Scheme 3
Organometallics, Vol. 26, No. 23, 2007 5561
Table 2. Results for Catalytic Dehydrogenative Silylation of
Arenes, Using 1 (10 mol %) and Ph3SiH at 120 °C (reaction
time of 24 h)
Scheme 4
entry
1
solvent
C6D6
alkene
TBE
products (yield)a
Ph3SiC6D5 (51%),
Ph3SiCHdCHtBu (11%)
Ph3SiC6H4CF3 (43%),b
Ph3SiCHdCHtBu (32%),
Ph3SiF (10%)
2
C6H5CF3
TBE
3
C6H5Cl
TBE
Ph3SiC6H4Cl (53%),b
Ph3SiCHdCHtBu (42%)
Ph3SiC6D5 (100%)
4c
5
C6D6
C6H5CF3
norbornene
norbornene
Ph3SiC6H4CF3 (81%),b
Ph3SiF (15%)
6
7
C6H5Cl
C6H5CH3
norbornene
norbornene
Ph3SiC6H4Cl (45%)b
Ph3SiC6H4CH3 (71%)b
b
a Based on GC/MS with a ferrocene standard. m- and p-substitutions
c
based only on GC/MS results. Reaction time is 48 h.
a catalytic system containing 10 mol % of 1, Ph3SiH, and
norbornene in benzene-d6, which resulted in complete conver-
sion to Ph3SiC6D5 after 2 days at 120 °C.
Related arene dehydrogenative silylations have been reported
by Berry and co-workers.17 Using [Cp*RhCl2]2 as a catalyst,
various arenes were silylated with Et3SiH at 150 °C, with TBE
as a hydrogen acceptor. The relative reactivities of monosub-
stituted arene compounds C6H5X, as measured by GC/MS,
revealed enhanced dehydrogenative coupling rates with more
electron-withdrawing arene substituents (e.g., CF3 (2.8) > F
(1.4) > H (1.0) > CH3 (0.32)). This trend reflects the results
often observed for nucleophilic C-H activation by low-valent
late transition metals,18,19 since more electron-deficient π-sys-
tems should react more rapidly with metal-based nucleophiles.
Thus, activation of electron-deficient arenes is kinetically
preferred over the activation of electron-rich arenes.19 In
comparison, the reactivity trend observed for our system is
similar although less pronounced:
mechanism, reversible R-Ph migration in 2 results in the 16-
electron intermediate (NSiN)Ir(SiPh3)(OTf) (C), which may be
capable of arene C-H bond activation at 120 °C to give the
cationic Ir(V) arylsilylhydride species D. A Si-C bond reductive
elimination step then produces the coupling product and an
iridium hydride species. Addition of a hydrogen acceptor, TBE,
and another Ph3SiH molecule to this iridium hydride intermedi-
ate would regenerate A, with elimination of tert-butylethane.
Presumably, the vinylsilane byproducts are formed by a compet-
ing, dehydrogenative hydrosilylation process.
Synthesis and Reactivity of [(NSiN)Ir(H)(coe)(THF)]-
[B(C6F5)4]. Given the interesting bond activation and catalytic
chemistry associated with 1, potentially more reactive complexes
CF3 (2.3) > Cl (2.0) > CH3 (1.2) > H (1.0)
were targeted. Specifically, an attempt was made to replace the
A proposed mechanism for catalytic dehydrogenative arene
silylation is given in Scheme 4. As with the silane redistribution
-
triflate anion in 1 with the less coordinating anion B(C6F5)4
.
The triflate moiety in 1 was exchanged using 1 equiv of Li-
(Et2O)3[B(C6F5)4] in dichloromethane to afford the five-
coordinate, cationic complex [(NSiN)Ir(H)(coe)][B(C6F5)4],
based on 1H NMR spectroscopy (dichloromethane-d2). Attempts
to isolate this cationic compound were unsuccessful, but the
analytically pure THF adduct [(NSiN)Ir(H)(coe)(THF)][B(C6F5)4]
(17) Ezbiansky, K.; Djurovich, P. I.; La Forest, M.; Sinning, D. J.; Zayes,
R.; Berry, D. H. Organometallics 1998, 17, 1455.
(18) (a) Jones, W. D.; Feher, F. J. J. Am. Chem. Soc. 1984, 106, 1650.
(b) Tolman, C. A.; Ittel, S. D.; English, A. D.; Jesson, J. P. J. Am. Chem.
Soc. 1979, 101, 1742.
(19) Jones, W. D.; Feher, F. J. Acc. Chem. Res. 1989, 22, 91.

5562 Organometallics, Vol. 26, No. 23, 2007
Sangtrirutnugul and Tilley
(10) was obtained from a 1:1 mixture of THF/pentane as a flaky,
yellow solid in 76% yield (eq 5). The 1H NMR resonance (THF-
d8) at δ -14.5 is assigned to Ir-H, and the IR band corre-
hydride bands at 2122 and 1778 cm-1, corresponding to cis-
hydride (H′) and trans-hydride (H), respectively.
Complex 11 is sparingly soluble in benzene but completely
soluble in THF and dichloromethane. Although 11 is stable in
THF solution and as a solid, it was found to slowly react with
dichloromethane solvent at room temperature (t1/2 ≈ 3 days) to
cleanly produce (NSiN)Ir(H)Cl(PPh3) and chloromethane. Reac-
tion of 11 with C2H4 in benzene-d6 at ambient temperature
resulted in decomposition of the starting materials, although the
1H NMR spectrum indicated the formation of C2H6.
sponding to the hydride ligand appears at 2035 cm-1
.
Previous attempts to synthesize Rh(III) complexes of the type
(NSiN)Rh(H)(R)(PPh3) included the alkylation of (NSiN)Rh-
(H)Cl(PPh3) with 1 equiv of Mg(CH2Ph)2(THF)2 in benzene to
afford the 18-electron, Rh(III) complex (NSiN)Rh(CH2Ph)Cl-
(PPh3) and toluene.6 Although the mechanism of this reaction
is still unclear, the alkyl hydride species (NSiN)Rh(H)(CH2-
Ph)(PPh3) is believed to be generated as a transient intermediate.
Given the greater strength of Ir-R (vs Rh-R) bonds, it was of
interest to investigate related alkylations with iridium in search
of intermediates and further mechanistic information.
Treatment of 10 with Ph3SiH in a variety of solvents including
dichloromethane-d2, PhF/benzene-d6, o-dichlorobenzene-d4, and
THF-d8 resulted in an intractable mixture of complexes similar
to those observed with reaction of 2 with Li(Et2O)3[B(C6F5)4].
Employing 10 as a catalyst for both silane redistribution and
dehydrogenative arene silylation did not reveal any improve-
ments over 1. For the dehydrogenative coupling reaction, 10
mol % of 10 in a benzene-d6 solution of Ph3SiH and norbornene
gave only 50% conversion to Ph3SiC6D5 compared to complete
conversion with 1 as a catalyst under the same reaction
conditions (2 days, 120 °C). The low yield is partly a result of
formation of a significant amount of side products including
Ph3SiF (12%), a product obtained from C-F bond activation
of the perfluoroaryl rings of B(C6F5)4-. In addition, the inferior
catalytic reactivity of 10 probably results from the lower
solubility of 10 in arene solvents and its decreased stability at
high temperature.
Synthesis of (NSiN)Ir(H)(R)(L) [R ) H, alkyl]. For
explorations of bond activations by the (NSiN)Ir fragment,
hydrides of the type (NSiN)Ir(H)(R)(L) (R ) H, alkyl) were
targeted. Such species were envisioned as precursors to Ir(I)
“(NSiN)Ir(L)” species via reductive elimination of R-H.
Furthermore, the coordinatively unsaturated (NSiN)Ir(L) is
expected to be a highly reactive fragment, given the chelate
ring strain that should be imposed by the sp3-hybridized silicon
center of the NSiN ligand in a square-planar complex.
A simple synthetic pathway to (NSiN)Ir(H)(R)(L) complexes
would involve halide displacement reactions at the iridium
center. Synthesis of the previously reported, 18-electron phos-
phine complex (NSiN)Ir(H)Cl(PPh3) involved addition of 1
equiv of PPh3 to (NSiN)Ir(H)Cl(coe) in dichloromethane.8
Reaction of (NSiN)Ir(H)Cl(PPh3) with 1 equiv of LiBEt3H in
THF at room temperature afforded a red microcrystalline solid,
characterized as the iridium dihydride complex (NSiN)IrH2-
(PPh3) (11) (eq 6).
Slow addition of a benzene solution of (NSiN)Ir(H)Cl(PPh3)
to a benzene solution of either 0.5 or 1.0 equiv of Mg(CH2-
Ph)2(THF)2 resulted in clean formation of the 18-electron
complex (NSiN)Ir(CH2Ph)Cl(PPh3) (12) and toluene (eq 7).
Analytically pure 12 was obtained from slow evaporation of a
benzene solution of the reaction mixture. The hydrocarbyl
intermediate (NSiN)Ir(H)(CH2Ph)(PPh3) was not detected in the
benzene-d6 reaction solution (by 1H NMR spectroscopy at room
temperature).
To explore related reactivity for a more electron-rich PMe3
derivative, attempts were made to synthesize (NSiN)Ir(H)Cl-
(PMe3). Slow addition of 1 equiv of PMe3 to (NSiN)Ir(H)Cl-
(coe) in dichloromethane afforded 13, obtained as a crystalline
yellow solid from THF (eq 8). According to 1H NMR
spectroscopy, the product was characterized as the desired
1
complex (NSiN)Ir(H)Cl(PMe3) (13) with H resonances at δ
2
2
-19.6 (d, JHP ) 22 Hz) and 1.30 (d, JHP ) 22 Hz),
corresponding to the hydride and PMe3 groups, respectively.
The 31P{1H} NMR spectrum contains a singlet at δ -40.3
assigned to the PMe3 ligand.
The 1H NMR spectrum of 11 in THF-d8 contains two sets of
quinolyl hydrogens, indicating the absence of mirror symmetry
for the molecule, and two hydride resonances as doublets of
doublets at δ -2.07 (2JHP ) 15 Hz, 2JHH′ ) 3.2 Hz) and -19.0
(2JH′P ) 23 Hz, 2JH′H ) 3.2 Hz). One of the hydride resonances
of 11 (δ -19.0) exhibits a chemical shift similar to that of its
chloride analogue (NSiN)Ir(H)Cl(PPh3) (δ -19.1), suggesting
a hydride ligand located cis to the silyl group. Consequently,
the more downfield-shifted peak at δ -2.07 is assigned to the
hydride trans to Si. The IR spectrum of 11 consists of two strong
Interestingly, addition of an excess amount (ca. 10 equiv) of
PMe3 to a dichloromethane solution of (NSiN)Ir(H)Cl(coe)
resulted in a different product. This product was identified, by
NMR spectroscopy, as the cationic κ2-NSiN complex [(κ2-
NSiN)Ir(H)(PMe3)3][Cl] (14) (eq 9). The 31P{1H} NMR spec-
trum of 14 consists of three distinct 31P{1H} multiplets at δ
2
2
-50.9 (dd, JPP′ ) 20 Hz, JPP′ ) 10 Hz), -51.2 (br m), and
-51.6 (br m). Two of these multiplets are broadened, presum-
ably as a result of their trans coordination to the strongly trans-
1
influencing hydride and silyl ligands. The H NMR spectrum

Silyl DeriVatiVes of [Bis(8-quinolyl)methylsilyl]iridium(III) Complexes
Organometallics, Vol. 26, No. 23, 2007 5563
Possible synthetic pathways to alkyl hydride complexes of
the type (NSiN)Ir(H)(R)(L) include methods that introduce the
NSiN ligand into a complex already containing an Ir-alkyl
bond. One such attempt involved addition of bis(8-quinolyl)-
methylsilane to 1 equiv of (PMe3)4IrMe in benzene to produce
the alkyl hydride Ir(III) product (κ1-NSiN)Ir(H)(Me)(PMe3)3
(15) as an orange solid in 71% yield (eq 11). The 31P{1H} NMR
spectrum in benzene-d6 exhibits three different PMe3 groups at
Figure 3. ORTEP diagram of the cationic complex 14 with thermal
ellipsoids shown at the 50% probability level. Hydrogen atoms and
a dichloromethane molecule are omitted for clarity. Selected bond
lengths (Å): Ir-P1 ) 2.363(3), Ir-P2 ) 2.262(3), Ir-P3 ) 2.411-
(3). Selected bond angles (deg): N1-Ir-Si ) 80.0(2), Si-Ir-P3
) 150.27(10), N1-Ir-P2 ) 175.1(2), P1-Ir-P2 ) 94.34(10).
δ -59.6 (br m), -60.6 (t, 2JPP ) 17 Hz), and -62.7 (t, 2JPP
)
17 Hz). A broad 31P{1H} shift at δ -59.6 is assigned to the
PMe3 ligand trans to the strongly trans-labilizing silicon.
According to 1H NMR spectroscopy, a hydride resonance
2
appears as a doublet of virtual triplets at δ -11.3 (dt, JHP
)
2
of 14 displays a hydride signal that is downfield-shifted (δ
-10.9) relative to that for 13 (δ -19.6). Consistent with the
NMR results, the IR spectrum reveals a strong band corre-
sponding to the hydride ligand at 2022 cm-1. For comparison,
the analogous stretch for 13 is at higher wave number (2105
cm-1).
131 Hz, JHP′ ≈ 17 Hz), suggesting a hydride with one trans
and two cis PMe3 groups.
The X-ray structure of 15 reveals a highly distorted octahedral
geometry about the iridium center with the NSiN ligand bound
in a monodentate fashion and the three PMe3 groups bonded in
a fac arrangement to iridium (Figure 4). The Si-Ir-P(2) angle
of 155.33(7)° is smaller than the ideal value of 180°, as a result
of a compact size of the hydride ligand and/or to avoid having
the PMe3 group directly trans to silicon. The iridium hydride
ligand was located trans to a PMe3 ligand and was positionally
refined.
Complex 15 is similar to complexes of the type (PMe3)3Ir-
(H)(Me)(SiR3), reported by Milstein and co-workers.21 The latter
complex, which also possesses a fac geometry, eliminates alkane
upon heating to give a reactive Ir(I) silyl derivative. This species
then undergoes quantitative and regioselective intramolecular
C-H activations. For comparison, thermal decomposition of
15 was conducted under similar reaction conditions (C6D6, 100
°C, 12 h). However, 1H and 31P{1H} NMR spectroscopy reveals
that the decomposition of 15 produces a complex mixture
including free PMe3.
X-ray quality single crystals of 14 were obtained from a 3:1
mixture of pentane and dichloromethane at room temperature.
Cationic complex 14 may be described as having an octahedral
geometry with the NSiN ligand bonded to the iridium center in
a bidentate fashion at the N and Si atoms (Figure 3). This
bidentate coordination presumably relieves angle strain at silicon
and allows a stronger Ir-P (vs Ir-N) bond to form. The N-Ir-
Si bite angle is small (80.0(2)°) due to the NSiN ligand rigidity.
The three PMe3 ligands occupy facial coordination sites about
the iridium center and there is an outer-sphere chloride atom.
Although the hydride ligand could not be located in the
difference Fourier map, it is presumed to occupy the coordina-
tion site trans to one of the PMe3 groups. As expected, the
longest Ir-P bond distance (2.411(3) Å) belongs to that trans
to silicon.
Synthesis and Reactivity of (NSiN)Ir(H)(OTf)(L) Com-
plexes. In the related (NSiN)Rh system, the 16-electron, cationic
complex [(NSiN)Rh(H)(PPh3)][B(C6F5)4] exhibits no bond
activation reactivity toward Et3SiH and H2 even at elevated
temperature.6 Given the higher stability of Ir(V) species, bond
activations involving (NSiN)Ir(III) complexes are expected to
be more facile. Thus, syntheses and reactivity studies of triflate
complexes of the type (NSiN)Ir(H)(OTf)(L) [L ) PPh3, PMe3]
were explored.
An attempt to remove a PMe3 ligand was made by the
addition of BPh3 to 14.20 Treatment of 14 with 3 equiv of BPh3
in THF at 90 °C resulted in the previously prepared complex
13 and Me3P‚BPh3 after 2 days, as evidenced by NMR
spectroscopy. However, prolonged heating of 13 in the presence
of BPh3 at 90 °C in THF did not yield the PMe3-free species
1
(NSiN)Ir(H)Cl (by H NMR spectroscopy). With complex 13
in hand, an attempt was made to obtain the PMe3 analogue of
12, (NSiN)IrH2(PMe3). Unfortunately, no reaction was observed
from addition of 1 equiv of LiBEt3H to a THF solution of 13
even upon heating the reaction mixture to 90 °C for 2 days.
The triflate complex (NSiN)Ir(H)(OTf)(PPh3) (16) was
isolated as a yellow solid (68% yield) from reaction of the
corresponding chloride complex with 1 equiv of AgOTf in
(20) Dioumaev, V. K.; Plossl, K.; Carroll, P. J.; Berry, D. H. Organo-
metallics 2000, 19, 3374.
(21) Aizenberg, M.; Milstein, D. J. Am. Chem. Soc. 1995, 117, 6456.

5564 Organometallics, Vol. 26, No. 23, 2007
Sangtrirutnugul and Tilley
[(NSiN)IrSiPh3(NCMe)2][OTf]2 (5) at 60 °C. Generally, aceto-
nitrile allows isolation of silyl complexes of the latter type (e.g.,
4-8).
Given the ability of 1 to activate silanes, it is not too surprising
that this compound is a catalyst for the redistribution of aryl
and hydrogen groups at silicon. At this time, the mechanism of
this process is uncertain. Several mechanisms for such redis-
tribution reactions have been proposed, including pathways
involving 1,3-migration of groups between silicon centers and
a silyl(silylene) complex,23 bimolecular reactions between silyl
and silylene complexes,24 and 1,2- or R-migrations involving
the metal and silicon centers.25 The mechanism of redistribution
as catalyzed by 1 likely involves R-migration chemistry, since
this has been observed in stoichiometric reactions of this system.
Interestingly, 1 represents one of the few complexes known
to catalyze the dehydrogenative coupling of silanes and are-
nes.17,26 Thus, (NSiN)Ir complexes may also participate in C-H
activation processes, and this suggests the possibility of further
catalytic reactions involving such iridium species. Given the
observed reactivity with PMe3, involving different binding
modes for the NSiN ligand, it appears that bond activations and
catalytic mechanisms may involve unsaturated intermediates
produced by dissociation of quinolyl groups. Further explora-
tions of this system are expected to provide more complete
descriptions of possible reactivity modes.
Figure 4. ORTEP diagram of complex 15 with thermal ellipsoids
shown at the 50% probability level. Hydrogen atoms, except Ir-
H, and half a diethyl ether molecule are omitted for clarity. Selected
bond lengths (Å): Ir-P1 ) 2.294(2), Ir-P2 ) 2.353(2), Ir-P3 )
2.325(2). Selected bond angles (deg): Si-Ir-P2 ) 155.33(7),
C20-Ir-P1 ) 172.9(2).
1
dichloromethane (eq 12). The H NMR spectrum of 16 (d8-
THF) contains an Ir-H resonance as a doublet at δ -16.5 (1JHP
) 19 Hz) with a broad 31P{1H} NMR shift at δ 9.3 in the 31P{
H} NMR spectrum. The infrared stretching band for the hydride
Experimental Procedures
General Procedures. All manipulations were conducted under
an N2 atmosphere using standard Schlenk techniques or a Vacuum
Atmospheres Unilab drybox. In general, solvents were distilled
under N2 from appropriate drying agents and stored in PTFE-valved
flasks. Deuterated solvents (Cambridge Isotopes) were dried with
appropriate drying agents and vacuum-transferred prior to use.
The reagents bis(8-quinolylmethyl)silane,6 (NSiN)Ir(H)Cl(coe),8
(Me3P)4IrMe,27 (NSiN)Ir(H)Cl(PPh3),8 Mg(CH2Ph)2(THF)2,28 and
Li(Et2O)3[B(C6F5)4]29 were prepared according to literature proce-
dures. Norbornene was purchased from Aldrich and purified by
vacuum sublimation. Cyclooctene and tert-butylethylene (Aldrich)
were distilled under N2 and stored in a silylated PTFE-valve storage
flask. All other chemicals were purchased from Aldrich or Gelest
and used without further purification. Ethylene (Air Gas) was used
as received.
1H (500.1 MHz), 13C{1H} (124.7 MHz), and 29Si{1H} (99.3
MHz) NMR spectra were acquired on Bruker DRX-500 or AV-
500 spectrometers. The DRX-500 spectrometer is equipped with a
5 mm Z-gradient proton/broad band probe, while the AV-500
instrument features a 5 mm TBI (triple inverse broad-band) probe
with Z-gradient. 19F (376.5 MHz) and 31P{1H} (162 MHz) NMR
spectra were obtained from an AVQ-400 spectrometer containing
a 5 mm QNP probe. Unless otherwise noted, NMR spectra were
recorded at room temperature and were referenced to protic
group was observed at 2120 cm-1
.
Alternatively, 16 may be synthesized in good yield (84%)
by addition of 1 equiv of PPh3 to 1 in dichloromethane at room
temperature. Monitoring the reaction by 1H NMR spectroscopy
showed that the reaction was complete within 1 h. Preliminary
reactivity studies with 16 indicate that it is rather inert, as it
does not react with Et3SiH or H2 in dichloromethane-d2, even
at temperatures up to 80 °C for 2 days.
Conclusions
The iridium triflate complex (NSiN)Ir(H)(OTf)(coe) (1) may
be viewed as a convenient synthon for the “(NSiN)Ir” fragment,
since the triflate anion is readily displaced, and the (H)(coe)
ligand set behaves as a cyclooctyl leaving group in reactions
with silanes. Thus, the activation of phenylsilanes by 1 produces
putative intermediates of the type (NSiN)Ir(SiRPh2)OTf (R )
H, Ph), which undergo rapid R-Ph migrations to produce 2 and
9, respectively. Iridium silyl complexes have previously been
associated with R-migration chemistry,9,11,22 but it is worth
noting that phenyl groups appear to migrate more readily than
hydride in this system, and R-H migration products have yet to
be observed for (NSiN)Ir compounds. The migration of phenyl
groups in this system appears to be reversible, as indicated by
the addition of acetonitrile to 2 to form the silyl derivatives
(23) (a) Jones, K. L.; Pannell, K. H. J. Am. Chem. Soc. 1993, 115, 11336.
(b) Pannell, K. H.; Cervantes, J.; Hernandez, C.; Cassias, J.; Vincenti, S.
Organometallics 1986, 5, 1056. (c) Pannell, K. H.; Rozell, J. M.; Hernandez,
C. J. Am. Chem. Soc. 1989, 111, 4482. (d) Pannell, K. H.; Wang, L.-J.;
Rozell, J. M. Organometallics 1989, 8, 550, and references therein.
(24) Grumbine, S. K.; Tilley, T. D. J. Am. Chem. Soc. 1994, 116, 6951.
(25) (a) Kobayashi, T.; Hayashi, T.; Yamashita, H.; Tanaka, M. Chem.
Lett. 1988, 1411. (b) Curtis, M. D.; Epstein, P. S. AdV. Organomet. Chem.
1981, 19, 213.
(26) (a) Dioumaev, V. K.; Yoo, B. R.; Procopio, L. J.; Carroll, P. J.;
Berry, D. H. J. Am. Chem. Soc. 2003, 125, 8936. (b) Dioumaev, V. K.;
Procopio, L. J.; Carroll, P. J.; Berry, D. H. J. Am. Chem. Soc. 2003, 125,
8043. (c) Kakiuchi, F.; Matsumoto, M.; Sonoda, M.; Fukuyama, T.; Chatani,
M.; Murai, S.; Furukawa, N.; Seki, Y. Chem. Lett. 2000, 7, 750.
(27) Thorn, D. L. Organometallics 1982, 1, 197.
(22) (a) Esteruelas, M. A.; Lahoz, F. J.; Oliva´n, M.; Offate, E.; Oro, L.
A. Organometallics 1994, 13, 4246. (b) Klei, S. R.; Bergman, R. G.; Tilley,
T. D. Organometallics 2001, 20, 3220.
(28) Shrock, R. R. J. Organomet. Chem. 1976, 122, 209.
(29) Massey, A. G.; Park, A. J. J. Organomet. Chem. 1964, 2, 245.

Silyl DeriVatiVes of [Bis(8-quinolyl)methylsilyl]iridium(III) Complexes
Organometallics, Vol. 26, No. 23, 2007 5565
impurities in the deuterated solvent (for 1H), solvent peaks (for 13C-
{1H}), CFCl3 (for 19F), SiMe4 (for 29Si{1H}), or 85% H3PO4 (for
31P{1H}). 2D NMR 1H,29Si{1H} HMBC experiments were carried
out to help assign 29Si{1H} NMR resonances to the corresponding
silyl groups. Elemental analyses were performed by the Micro-
Mass Facility in the College of Chemistry at the University of
California, Berkeley. GC-MS was conducted using an Agilent
Technology 6890N 6C system with an HP-5MS column. Infrared
spectra were recorded either as KBr pellets on a Mattson FTIR
3000 instrument or as Nujol mulls on a Nicolet Nexus 6700 FT-IR
spectrometer with a liquid nitrogen cooled MCT-B detector.
500 MHz): δ 9.42 (d JHH ) 5.0 Hz, of d JHH ) 1.5 Hz, 2 H, ArH),
7.90 (d JHH ) 6.8 Hz, of d JHH ) 1.2 Hz, 2 H, ArH), 7.35 (d JHH
) 8.2 Hz, of d JHH ) 1.2 Hz, 2 H, ArH), 7.14 (m, 2 H, ArH), 7.09
(m, 2 H, ArH), 6.66 (d JHH ) 8.2 Hz, of d JHH ) 5.0 Hz, 2 H,
ArH), 0.71 (s, 3 H, SiCH3), 0.023 (s, 27 H, Si[OSi(CH3)3]3). 13C-
{1H} NMR (C6D6, 125 MHz): δ 158.8, 155.1, 141.7, 137.8, 135.6,
129.3, 128.8, 127.6, 121.8 (aryl carbons), 2.85 (SiCH3), 2.12 (Si-
[OSi(CH3)3]3). 19F NMR (C6D6, 376.5 MHz): δ -76.8 (s). 29Si-
{1H} NMR (C6D6, 99 MHz): δ 8.8 (s, SiCH3), 4.1 (s, Si-
[OSi(CH3)3]3). Anal. Calcd (%) for C29H42N2Si5O6SF3Ir: C, 37.20,
H, 4.52, N, 2.99. Found: C, 36.84, H, 4.28, N, 3.14.
(NSiN)Ir(H)(OTf)(coe) (1). A 200 mL Schlenk flask equipped
with a stir bar was covered with an aluminum foil and charged
with AgOTf (0.28 g, 1.1 mmol) and (NSiN)Ir(H)(Cl)(coe) (0.62 g,
0.97 mmol). To this solid mixture was added 100 mL of CH2Cl2,
and the reaction mixture was stirred at ambient temperature for 4
h, after which the resulting mixture was allowed to settle, giving a
beige-colored precipitate. The off-white supernatant was filtered
via cannula filtration. The remaining residue was washed with CH2-
Cl2 (2 × 10 mL). The filtrates were combined and evaporated to
dryness to give the crude product. Vapor diffusion of diethyl ether
into a concentrated CH2Cl2 solution of the product afforded an
analytically pure compound as an off-white precipitate in 93% yield
(0.68 g, 0.90 mmol). 1H NMR (CD2Cl2, 500 MHz): δ 9.66 (d JHH
) 5.0 Hz, 1 H, ArH), 9.59 (br s, 1 H, ArH), 8.33 (d JHH ) 7.0 Hz,
1 H, ArH), 8.28 (d JHH ) 8.5 Hz, 1 H, ArH), 8.06 (d JHH ) 6.5
Hz, 1 H, ArH), 7.98 (d JHH ) 6.0 Hz, 1 H, ArH), 7.79 (m, 2 H,
ArH), 7.63 (m, 2 H, ArH), 7.54 (m, 1 H, ArH), 7.35 (br m, 2 H,
ArH), 4.51 (m, 1 H, CHdCH of coe), 3.72 (m, 1 H, CHdCH of
coe), 2.07 (br m, 1 H, CH of coe), 1.91 (br m, 1 H, CH of coe),
1.65 (br m, 1 H, CH of coe), 1.31 (br m, 5 H, CH of coe), 1.10 (br
m, 1 H, CH of coe), 0.980 (s, 3 H, SiCH3), 0.820 (br m, 1 H, CH
of coe), -14.7 (br s, 1 H, IrH). 13C{1H} NMR (CD2Cl2, 125
MHz): δ 154.2, 153.9, 152.4, 152.3, 145.6, 144.8, 139.7, 139.2,
135.4, 134.9, 129.9, 129.2, 129.1, 128.7, 128.2, 127.8, 123.1, 122.6
(aryl carbons), 67.2 (IrCH), 66.3 (IrCH), 32.6, 31.8, 30.9, 30.0,
26.5, 26.4 (alkyl carbons), -7.40 (SiCH3). 19F NMR (CD2Cl2, 376.5
MHz): δ -75.9 (s). 29Si{1H} NMR (CD2Cl2, 99 MHz): δ -8.2
(s). Anal. Calcd (%) for C28H30N2SiO3SF3Ir: C, 44.72, H, 4.02, N,
3.73. Found: C, 44.33, H, 3.99, N, 3.61. IR (cm-1): νIrH 2161.
[(NSiN)IrSi(OSiMe3)3(NCMe)2][OSO2CF3] (4). (1) To a stirred
10 mL CH3CN solution of 1 (0.055 g, 0.073 mmol) was added a
5 mL CH3CN solution of (Me3SiO)3SiH (0.023 g, 0.078 mmol).
After 4 h at room temperature, the reaction mixture was filtered
through Celite, resulting in a clear yellow filtrate. The CH3CN
filtrate was concentrated to approximately 2 mL and washed with
2 × 2 mL of pentane. The resulting solution was evaporated to
dryness, providing a crystalline yellow residue in 79% yield (0.056
g, 0.058 mmol).
(2) Alternatively, 4 was generated by heating a 5 mL CH3CN
solution of 3 at 70 °C for 12 h. The reaction was quantitative
according to 1H NMR spectroscopy. 1H NMR (CD3CN, 500
MHz): δ 9.60 (d JHH ) 5.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH),
9.38 (d JHH ) 5.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.35 (d JHH
) 8.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.28 (d JHH ) 8.5 Hz, of
d JHH ) 1.5 Hz, 1 H, ArH), 8.26 (d JHH ) 6.0 Hz, of d JHH ) 1.5
Hz, 1 H, ArH), 8.07 (d JHH ) 6.0 Hz, of d JHH ) 1.5 Hz, 1 H,
ArH), 7.83 (d JHH ) 8.0 Hz, of d JHH ) 1.2 Hz, 1 H, ArH), 7.71
(d JHH ) 8.0 Hz, of d JHH ) 1.2 Hz, 1 H, ArH), 7.62 (d JHH ) 8.0
Hz, of d JHH ) 6.5 Hz, 1 H, ArH), 7.53 (d JHH ) 8.5 Hz, of d JHH
) 5.0 Hz, 1 H, ArH), 7.49 (d JHH ) 8.0 Hz, of d JHH ) 6.0 Hz, 1
H, ArH), 7.34 (d JHH ) 8.5 Hz, of d JHH ) 5.5 Hz, 1 H, ArH),
2.12 (s, 3 H, IrNCCH3), 1.18 (s, 3 H, SiCH3), -0.136 (s, 27 H,
Si[OSi(CH3)3]3). 13C{1H} NMR (CD3CN, 125 MHz): δ 156.47,
156.45, 152.9, 152.6, 148.4, 148.0, 140.2, 139.5, 137.0, 136.7,
130.5, 130.3, 129.6, 129.5, 128.8, 128.5, 123.2, 123.1 (aryl carbons),
118.7 (IrNCCH3), 4.70 (IrNCCH3), 2.66 (Si[OSi(CH3)3]3), -6.79
(SiCH3). 19F NMR (CD3CN, 376.5 MHz): δ -78.6 (s). 29Si{1H}
NMR (CD3CN, 99 MHz): δ 1.4 (s, SiCH3), 1.6 (s, Si[OSi(CH3)3]3).
Anal. Calcd (%) for C33H48N4Si5O6SF3Ir: C, 38.91, H, 4.75, N,
5.50. Found: C, 39.23, H, 4.99, N, 5.47. IR (cm-1): νCN 2274
(w), 2297 (w).
(NSiN)IrPh(SiPh2OTf) (2). To a 10 mL C6H6 solution of 1
(0.085 g, 0.11 mmol) was added 5 mL of a C6H6 solution of Ph3-
SiH (0.030 g, 0.12 mmol). After 4 h of stirring at room temperature,
the homogeneous, bright yellow reaction mixture was evacuated
to dryness. The remaining yellow residue was then dissolved in 10
mL of diethyl ether, and the resulting solution was filtered through
Celite. The solution was then concentrated to approximately 3 mL.
At room temperature, orange crystals were obtained in 88% yield
[(NSiN)IrSiPh3(NCMe)2][OSO2CF3] (5). To a 10 mL CH3CN
solution of 1 (0.065 g, 0.086 mmol) was added a 5 mL CH3CN
solution of Ph3SiH (0.025 g, 0.096 mmol). After 12 h of stirring at
room temperature, the reaction mixture was evaporated to dryness
to give a yellow solid. This solid was washed with pentane (2 × 2
mL) and dissolved in approximately 5 mL of diethyl ether. This
solution was then concentrated to 3 mL. Approximately 0.5 mL of
CH3CN was added to help solubilize the product. The yellow,
crystalline product was obtained at -30 °C in 56% yield (0.045 g,
0.048 mmol). 1H NMR (CD3CN, 500 MHz): δ 9.47 (d JHH ) 5.0
Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 9.37 (d JHH ) 5.5 Hz, of d JHH
) 1.5 Hz, 1 H, ArH), 8.37 (d JHH ) 8.5 Hz, of d JHH ) 1.5 Hz, 1
H, ArH), 8.19 (d JHH ) 6.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH),
8.16 (d JHH ) 8.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 7.84 (d JHH
) 8.0 Hz, of d JHH ) 1.0 Hz, 1 H, ArH), 7.74 (d JHH ) 7.0 Hz, of
d JHH ) 1.5 Hz, 1 H, ArH), 7.61 (d JHH ) 8.0 Hz, of d JHH ) 7.0
Hz, 1 H, ArH), 7.57 (d JHH ) 8.5 Hz, of d JHH ) 1.0 Hz, 1 H,
ArH), 7.52 (d JHH ) 8.5 Hz, of d JHH ) 5.0 Hz, 1 H, ArH), 7.35
(m, 1 H, ArH), 7.18 (d JHH ) 8.0 Hz, of d JHH ) 5.5 Hz, 1 H,
ArH), 7.15 (m, 6 H, ArH), 7.10 (m, 3 H, ArH), 7.01 (m, 6 H, ArH),
2.10 (s, 3 H, IrNCCH3), 0.801 (s, 3 H, SiCH3). 13C{1H} NMR (CD3-
CN, 125 MHz): δ 156.12, 156.1, 148.0, 147.7, 141.7, 140.4, 139.8,
136.8, 136.7, 136.4, 130.33, 130.31, 129.71, 129.66, 129.3, 128.8,
128.7, 128.1, 127.6, 123.5, 123.2 (aryl carbons), 121.6 (br,
1
(0.089 g, 0.099 mmol). H NMR (C6D6, 500 MHz): δ 9.62 (m, 1
H, ArH), 9.18 (d JHH ) 6.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH),
7.76 (m, 2 H, ArH), 7.71 (m, 2 H, ArH), 7.48 (m, 2 H, ArH), 7.05-
6.80 (m, 14 H, ArH), 6.63 (m, 1 H, ArH), 6.50 (m, 3 H, ArH),
6.44 (m, 1 H, ArH), 1.37 (s, 3 H, SiCH3). 13C{1H} NMR (C6D6,
125 MHz): δ 153.8, 151.2, 150.2, 146.7, 146.1, 140.4, 140.0, 138.4,
137.5, 137.3, 136.5, 135.9, 134.4, 133.7, 131.8, 129.3, 129.2, 129.0,
127.3, 127.2, 127.1, 126.9, 126.5, 122.1, 122.0, 121.7 (aryl carbons),
-5.70 (SiCH3). 19F NMR (C6D6, 376.5 MHz): δ -74.3 (s). 29Si-
{1H} NMR (C6D6, 99 MHz): δ 54.0 (s, SiPh2OTf), -8.4 (s, SiCH3).
Anal. Calcd (%) for C38H30N2Si2O3SF3Ir: C, 50.70, H, 3.36, N,
3.11. Found: C, 50.73, H, 3.44, N, 3.12.
[(NSiN)IrSi(OSiMe3)3(OTf)]n (3). To a 5 mL C6H6 solution of
1 (0.11 g, 0.15 mmol) was added (Me3SiO)3SiH (0.046 g, 0.16
mmol) in 5 mL of C6H6. The reaction mixture was stirred for 1 h,
after which the clear yellow solution was filtered through Celite.
The filtrate was concentrated to approximately 2 mL, and 1 mL of
diethyl ether was added. At room temperature, a yellow flaky solid
was obtained in 48% yield (0.065 g, 0.069 mmol). 1H NMR (C6D6,

5566 Organometallics, Vol. 26, No. 23, 2007
Sangtrirutnugul and Tilley
1
IrNCCH3), 4.55 (IrNCCH3), -6.30 (SiCH3). 19F NMR (CD3CN,
376.5 MHz): δ -76.8 (s). 29Si{1H} NMR (CD3CN, 99 MHz): δ
-1.2 (s, SiCH3), -25.3 (s, SiPh3). Anal. Calcd (%) for C40H33N3-
Si2O3SF3Ir: C, 51.04, H, 3.53, N, 4.46. Found: C, 51.38, H, 3.58,
N, 4.41. IR (cm-1): νCN 2187 (w), 2297 (w).
(0.065 g, 0.087 mmol). H NMR (CD3CN, 500 MHz): δ 9.54 (d
JHH ) 6.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 9.40 (d JHH ) 5.5
Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.40 (d JHH ) 11 Hz, of d JHH
) 2.0 Hz, 1 H, ArH), 8.24 (d JHH ) 8.5 Hz, of d JHH ) 1.5 Hz, 1
H, ArH), 8.23 (d JHH ) 10 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.16
(m, 1 H, ArH), 7.86 (d JHH ) 10 Hz, of d JHH ) 2.0 Hz, 1 H,
ArH), 7.73 (d JHH ) 10 Hz, 1 H, ArH), 7.62 (d JHH ) 10 Hz, of
d JHH ) 8.5 Hz, 1 H, ArH), 7.58-7.53 (m, 2 H, ArH), 7.22 (d JHH
) 10 Hz, of d JHH ) 7.0 Hz, 1 H, ArH), 7.15 (m, 3 H, ArH), 7.06
(m, 2 H, ArH), 3.84 (d 2JHH′ ) 6.0 Hz, 1JSiH ) 169 Hz, SiHH′Ph),
3.39 (d 2JHH′ ) 6.0 Hz, 1JSiH′ ) 171 Hz, 1 H, SiHH′Ph), 2.12 (s, 3
H, CH3CN), 1.09 (s, 3 H, SiCH3). 13C{1H} NMR (CD3CN, 125
MHz): δ 156.1, 156.0, 153.8, 152.7, 147.3, 147.0, 140.4, 139.6,
138.7, 137.2, 137.0, 135.3, 130.5, 130.3, 130.0, 129.9, 129.1, 128.6,
128.3, 128.1, 123.5, 123.4 (aryl carbons), 4.10 (IrNCCH3), -8.8
(SiCH3). 19F NMR (CD3CN, 376.5 MHz): δ -76.8 (s). 29Si{1H}
NMR (CD3CN, 99 MHz): δ 2.2 (s, SiCH3), -51.6 (s, SiH2Ph).
Anal. Calcd (%) for C30H28N4Si2O3SF3Ir: C, 43.41, H, 3.40, N,
6.75. Found: C, 43.39, H, 3.22, N, 7.09. IR (cm-1): νCN 2273
(w), 2295 (w); νSiH 2051 (br m).
[(NSiN)IrSiEt3(NCMe)2][OSO2CF3] (6). To a 15 mL CH3CN
solution of 1 (0.14 g, 0.19 mmol) was added a 5 mL CH3CN
solution of Et3SiH (30 µL, 0.19 mmol). The reaction mixture was
stirred at ambient temperature for 1 day, after which it was filtered
through Celite and a glass fiber filter. The yellow CH3CN filtrate
was concentrated to approximately 2 mL and washed with 2 × 2
mL of pentane. The resulting solution was evaporated to dryness,
providing a foamy yellow residue in 86% yield (0.13 g, 0.16 mmol).
1H NMR (CD3CN, 500 MHz): δ 9.72 (d JHH ) 5.5 Hz, of d JHH
) 1.0 Hz, 1 H, ArH), 9.46 (d JHH ) 5.0 Hz, of d JHH ) 2.0 Hz, 1
H, ArH), 8.36 (d JHH ) 8.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH),
8.30 (d JHH ) 8.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.24 (d JHH
) 6.5 Hz, of d JHH ) 1.0 Hz, 1 H, ArH), 8.10 (d JHH ) 7.0 Hz, of
d JHH ) 2.0 Hz, 1 H, ArH), 7.83 (d JHH ) 8.0 Hz, of d JHH ) 1.0
Hz, 1 H, ArH), 7.73 (d JHH ) 8.0 Hz, of d JHH ) 1.0 Hz, 1 H,
ArH), 7.61 (d JHH ) 8.0 Hz, of d JHH ) 6.5 Hz, 1 H, ArH), 7.55-
7.50 (m, 2 H, ArH), 7.32 (d JHH ) 8.5 Hz, of d JHH ) 5.5 Hz, 1
H, ArH), 2.15 (s, 3 H, IrNCCH3), 1.10 (s, 3 H, SiCH3), 0.66 (t JHH
) 7.8 Hz, 9 H, SiCH2CH3), 0.51 (m, 3 H, SiCHH’CH3), 0.39 (m,
3 H, SiCHH’CH3). 13C{1H} NMR (CD3CN, 125 MHz): δ 156.8,
156.1, 152.8, 152.4, 148.6, 148.0, 140.0, 139.4, 136.6, 136.5, 130.3,
130.2, 129.64, 129.56, 129.1, 128.5, 123.4, 123.2 (aryl carbons),
119.9 (IrNCCH3), 8.96 (SiCH2CH3), 6.90 (SiCH2CH3), 4.17
(IrNCCH3), -6.79 (SiCH3). 19F NMR (CD3CN, 376.5 MHz): δ
-76.8 (s). 29Si{1H} NMR (CD3CN, 99 MHz): δ 1.8 (s, SiCH3),
-12.8 (s, Si(CH2CH3)3). Anal. Calcd (%) for C28H33N3Si2O3SF3Ir:
C, 42.19, H, 4.17, N, 5.27. Found: C, 42.21, H, 4.14, N, 5.27. IR
(cm-1): νCN 2273 (w), 2291 (w).
Observation of (NSiN)IrPh[Si(H)PhOTf] (9). Compound 9 was
generated in situ by adding neat Ph2SiH2 (0.007 g, 0.040 mmol) to
an approximately 3 mL benzene-d6 solution of 1 (0.03 g, 0.04
mmol), ferrocene (0.004 g, 0.02 mmol), and cyclooctene (0.005 g,
0.04 mmol). The reaction mixture was allowed to stand at ambient
temperature for 1 h before being analyzed by multinuclear NMR
spectroscopy. H NMR (C6D6, 500 MHz): δ 5.49 (s JSiH ) 176
Hz, 1 H, SiHPh), 0.761 (s, 3 H, SiCH3). 19F NMR (C6D6, 376.5
MHz): δ -73.4 (s). 29Si{1H} NMR (C6D6, 99 MHz): δ -24.5 (s,
Si(H)PhOTf).
1
1
[(NSiN)Ir(H)(coe)(THF)][B(C6F5)4] (10). To a 10 mL CH2Cl2
solution of Li(Et2O)3[B(C6F5)4] (0.15 g, 0.16 mmol) was added
dropwise a 20 mL CH2Cl2 solution of 1 (0.11 g, 0.16 mmol). The
reaction mixture was vigorously stirred at room temperature for 1
h, after which it was filtered through Celite. The clear yellow
solution was evaporated to dryness and redissolved in 10 mL of
THF. The THF solution was concentrated to approximately 2 mL
and layered with 4 mL of pentane. At -30 °C, a yellow crystalline
solid was obtained in 76% yield (0.17 g, 0.12 mmol). Due to
broadened 1H NMR resonances, all multinuclear NMR spectra were
[(NSiN)IrSiHPh2(NCMe)2][OSO2CF3] (7). To a stirred 10 mL
CH3CN solution of 1 (0.060 g, 0.080 mmol) was slowly added a 5
mL CH3CN solution of Ph2SiH2 (0.016 g, 0.087 mmol). After 2 h,
the reaction mixture was filtered through Celite and a glass fiber
filter. The yellow CH3CN solution was concentrated to ap-
proximately 2 mL and washed with 2 × 2 mL of pentane. The
resulting solution was evaporated to dryness to give the yellow
1
1
product in 82% yield (0.054 g, 0.066 mmol). H NMR (CD3CN,
obtained at 50 °C. H NMR (THF-d8, 500 MHz): δ 9.75 (br s, 2
500 MHz): δ 9.53 (d JHH ) 5.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH),
9.19 (d JHH ) 5.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.38 (d JHH
) 8.5 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 8.24 (d JHH ) 7.0 Hz, of
d JHH ) 1.5 Hz, 1 H, ArH), 8.13-8.11 (m, 2 H, ArH), 7.84 (d JHH
) 8.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 7.71-7.66 (m, 3 H,
ArH), 7.60 (d JHH ) 8.0 Hz, of d JHH ) 7.0 Hz, 1 H, ArH), 7.56
(d JHH ) 8.0 Hz, of d JHH ) 5.0 Hz, 1 H, ArH), 7.52 (d JHH ) 8.0
Hz, of d JHH ) 7.0 Hz, 1 H, ArH), 7.32-7.25 (m, 3 H, ArH),
7.03-6.98 (m, 2 H, ArH), 6.87 (m, 4 H, ArH), 4.33 (s 1JSiH ) 173
Hz, 1 H, SiHPh2), 2.16 (s, 3 H, IrNCCH3), 1.07 (s, 3 H, SiCH3).
13C{1H} NMR (CD3CN, 125 MHz): δ 156.04, 155.98, 153.6, 152.7,
147.5, 147.0, 140.9, 140.40, 140.36, 139.4, 137.2, 136.9, 135.9,
134.7, 130.5, 130.2, 129.9, 129.8, 128.9, 128.62, 128.58, 128.4,
128.0, 127.9, 123.5, 123.4 (aryl carbons), 4.03 (IrNCCH3), -8.8
(SiCH3). 19F NMR (CD3CN, 376.5 MHz): δ -76.8 (s). 29Si{1H}
NMR (CD3CN, 99 MHz): δ 2.8 (s, SiCH3), -25.0 (s, SiHPh2).
Anal. Calcd (%) for C34H29N4Si2O3SF3Ir: C, 47.22, H, 3.38, N,
4.86, S, 3.71. Found: C, 46.92, H, 3.30, N, 3.44. IR (cm-1): νCN
2271 (w), 2294 (w); νSiH 2040 (m).
H, ArH), 8.52 (d JHH ) 8.0 Hz, 1 H, ArH), 8.43 (d JHH ) 8.0 Hz,
1 H, ArH), 8.16 (d JHH ) 6.5 Hz, 1 H, ArH), 8.08 (d JHH ) 6.5
Hz, 1 H, ArH), 7.91 (d JHH ) 8.0 Hz, 1 H, ArH), 7.84 (d JHH
)
8.0 Hz, 1 H, ArH), 7.71 (d JHH ) 8.0 Hz, of d JHH ) 5.0 Hz, 1 H,
ArH), 7.59 (m, 2 H, ArH), 7.43 (br m, 1 H, ArH), 4.20 (br m, 1 H,
CH)CH of coe), 3.79 (br m, 1 H, CHdCH of coe), 2.20 (br m, 1
H, CH of coe), 2.04 (br m, 1 H, CH of coe), 1.60-1.12 (br m, 9
H, CH of coe), 1.07 (s, 3 H, SiCH3), 0.90 (br m, 1 H, CH of coe),
-14.5 (br s, 1 H, IrH). 13C{1H} NMR (THF-d8, 125 MHz): δ 155.0,
154.4 (br s), 153.4, 153.1, 145.8, 145.0, 141.3, 140.9, 136.8, 136.2,
130.9, 130.2, 129.7, 129.2, 128.8, 123.5, 122.9, (aryl carbons), 68.2
(THF), 66.8 (CHdCH of coe), 65.8 (CHdCH of coe), 33.0, 32.4,
31.8, 30.1, 27.04, 26.95 (alkyl carbons), 26.4 (THF), -7.23 (SiCH3).
19F NMR (THF-d8, 376.5 MHz): δ -133.8 (br s), -166.3 (t),
-169.7 (br t). 29Si{1H} NMR (THF-d8, 99 MHz): δ -4.2 (s). 11B-
{1H} NMR (THF-d8, 128.4 MHz): δ -16.7 (s). Anal. Calcd (%)
for C55H38N2SiOBF20Ir: C, 48.78, H, 2.81, N, 2.07. Found: C,
49.16, H, 2.91, N, 2.35. IR (cm-1): νIrH 2035.
(NSiN)IrH2(PPh3) (11). To a 15 mL THF solution of (NSiN)-
Ir(H)Cl(PPh3) (0.095 g, 0.12 mmol) was slowly added a 1.0 M
THF solution of LiBEt3H (0.13 mL, 0.13 mmol) at ambient
temperature. A color change to orange was immediately observed.
The reaction mixture was stirred for 4 h before all volatiles were
removed under vacuum. The remaining orange solid was dissolved
in 20 mL of THF. The resulting solution was filtered through Celite
and concentrated to a volume of 3 mL. Cooling this THF solution
[(NSiN)IrSiH2Ph(NCMe)2][OSO2CF3] (8). To a stirred 10 mL
CH3CN solution of 1 (0.085 g, 0.11 mmol) was added a 5 mL
CH3CN solution of PhSiH3 (0.013 mg, 0.12 mmol). After 1 h at
room temperature, the reaction solution was filtered through Celite,
and the resulting CH3CN filtrate was concentrated to approximately
2 mL and washed with 2 × 2 mL of pentane. The yellow solution
was evaporated to dryness, resulting in a yellow solid in 77% yield

Silyl DeriVatiVes of [Bis(8-quinolyl)methylsilyl]iridium(III) Complexes
to -30 °C afforded orange blocks in 78% yield (0.071 g, 0.094
Organometallics, Vol. 26, No. 23, 2007 5567
(%) for C22H25N2SiPIrCl: C, 43.73, H, 4.17, N, 4.64. Found: C,
43.82, H, 4.21, N, 4.49. IR (cm-1): νIrH 2105.
1
mmol). H NMR (THF-d8, 400 MHz): δ 10.85 (m, 1 H, ArH),
[(κ2-NSiN)Ir(H)(PMe3)3][Cl] (14). To a 20 mL CH2Cl2 solution
of (NSiN)Ir(H)Cl(coe) (0.11 g, 0.20 mmol) was added neat PMe3
(0.21 µL, 2.0 mmol). After 8 h of stirring at room temperature, the
solution was evaporated to dryness under vacuum. The remaining
yellow residue was dissolved in approximately 8 mL of CH2Cl2,
and the resulting solution was filtered through Celite and concen-
trated to 2 mL. Layering this solution with ca. 6 mL of pentane at
room temperature afforded a yellow, crystalline product in 81%
9.99 (d JHH ) 4.8 Hz, 1 H, ArH), 8.17 (d JHH ) 8.0 Hz, 1 H,
ArH), 7.97 (d JHH ) 6.8 Hz, 1 H, ArH), 7.83 (d JHH ) 7.2 Hz, of
d JHH ) 0.8 Hz, 2 H, ArH), 7.58 (m, 6 H, ArH), 7.51 (d JHH ) 8.0
Hz, 1 H, ArH), 7.32 (m, 2 H, ArH), 7.25 (m, 1 H, ArH), 7.10 (d
JHH ) 8.0 Hz, of d JHH ) 5.2 Hz, 1 H, ArH), 6.98 (m, 9 H, ArH),
6.68 (d JHH ) 8.0 Hz, of d JHH ) 4.8 Hz, 1 H, ArH), 0.40 (s, 3 H,
2
2
SiCH3), -2.07 (d JHP ) 15 Hz, of d JHH′ ) 3.2 Hz, 1 H, IrH),
2
2
-19.0 (d JH′P ) 23 Hz, of d JH′H ) 3.2 Hz, 1 H, IrH′). 13C{1H}
NMR (THF-d8, 125 MHz): δ 163.7, 161.0, 156.4, 155.81, 155.79,
155.0, 153.6, 135.2, 134.8 (JCP ) 2.5 Hz), 134.7, 132.6 (JCP ) 7.5
Hz), 131.7, 131.6, 126.8, 126.0 (JCP ) 2.5 Hz), 124.8 (JCP ) 53.8
Hz), 124.5, 124.4, 119.9, 119.8, 119.5 (aryl carbons), -8.2 (SiCH3).
29Si{1H} NMR (THF-d8, 99 MHz): δ 19.1 (2JSiP ) 12 Hz). 31P-
{1H} NMR (THF-d8, 162 MHz): δ 26.0 (s). Anal. Calcd (%) for
C37H32N2SiPIr: C, 58.80, H, 4.27, N, 3.71. Found: C, 58.91, H,
4.51, N, 3.58. IR (cm-1): νIrH 2122; νIrH′ 1779.
1
yield (0.12 g, 0.16 mmol). H NMR (CD2Cl2, 500 MHz): δ 9.86
(m, 1 H, ArH), 8.54 (m, 1 H, ArH), 8.47 (d JHH ) 8.0 Hz, 1 H,
ArH), 8.07 (d JHH ) 8.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 7.85
(d JHH ) 8.0 Hz, of d JHH ) 5.0 Hz, 1 H, ArH), 7.79 (m, 2 H,
ArH), 7.64 (d JHH ) 8.0 Hz, 1 H, ArH), 7.56 (m, 1 H, ArH), 7.30
(d JHH ) 8.0 Hz, of d JHH ) 4.0 Hz, 1 H, ArH), 7.06 (d JHH ) 7.5
Hz, 1 H, ArH), 1.99 (d 2JHP ) 9.5 Hz, 9 H, P(CH3)3), 1.54 (d 2JHP′
3
) 8.0 Hz, 9 H, P′(CH3)3), 1.40 (d JHP′′ ) 2.5 Hz, 3 H, SiCH3),
1.06 (d 2JHP′′ ) 8.5 Hz, 9 H, P′′(CH3)3), -10.9 (m, 1 H, IrH). 13C-
{1H} NMR (CD2Cl2, 125 MHz): δ 163.6 (m), 157.4, 154.9, 154.6,
153.7, 151.9, 148.1, 139.9, 137.8, 136.6, 135.6 (d JCP ) 2.2 Hz),
128.6, 128.4, 128.2, 127.8, 126.2, 1213.3 (br m), 121.0 (aryl
carbons), 24.7 (m, P(CH3)3), 21.5 (d 2JCP ) 24 Hz, of d 3JCP ) 1.9
Hz, P′(CH3)3), 19.3 (d 2JCP ) 16 Hz, of d 3JCP ) 4.0 Hz, P′′(CH3)3),
6.7 (m, SiCH3). 29Si{1H} NMR (CD2Cl2, 99 MHz): δ -6.0 (m).
(NSiN)Ir(CH2Ph)Cl(PPh3) (12). To a 5 mL C6H6 solution of
(NSiN)Ir(H)Cl(PPh3) (0.090 g, 0.11 mmol) was slowly added a 5
mL C6H6 solution of Mg(CH2Ph)2(THF)2 (0.025 g, 0.071 mmol).
The reaction mixture immediately became reddish-orange, and it
was allowed to stir at ambient temperature for 30 min. Then, the
reaction mixture was concentrated to a volume of approximately 6
mL and filtered through Celite and a glass fiber filter. Slow
evaporation of this filtrate at room temperature afforded a yellow
powder in 68% yield (0.068 g, 0.077 mmol). 1H NMR (C6D6, 500
MHz): δ 9.73 (t JHH ) 5.0 Hz, of d JHH ) 2.0 Hz, 2 H, ArH),
8.16 (d JHH ) 7.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 7.84 (d JHH
) 5.0 Hz, of d JHH ) 3.6 Hz, 1 H, ArH), 7.40 (m, 6 H, ArH), 7.26
(d JHH ) 8.0 Hz, of d JHH ) 2.0 Hz, 1 H, ArH), 7.19 (m, 1 H,
ArH), 7.06 (d JHH ) 8.0 Hz, of d JHH ) 1.5 Hz, 1 H, ArH), 6.85
(m, 2 H, ArH), 6.79 (t JHH ) 8.0 Hz, of d JHH ) 1.5 Hz, 6 H,
ArH), 6.72 (m, 4 H, ArH), 6.52 (d JHH ) 8.0 Hz, of d JHH ) 5.0
Hz, 1 H, ArH), 6.49 (d JHH ) 8.0 Hz, of d JHH ) 5.0 Hz, 1 H,
ArH), 6.32 (v br s, 2 H, ArH), 6.14 (t JHH ) 8.0 Hz, 1 H, ArH),
1.98 (vt JHH′ ≈ JHP ≈ 7.0 Hz, 1 H, CHH′Ph), 1.92 (vt JHH′ ≈ JH′P
≈ 7.0 Hz, 1 H, CHH′Ph), 1.26 (s, 3 H, SiCH3). 13C{1H} NMR
(C6D6, 125 MHz): δ 150.0, 149.9, 149.6, 149.3, 145.1, 140.4, 139.8,
138.1, 137.72, 137.66, 135.0, 134.1, 134.0, 129.5 (1JCP ) 50 Hz),
128.53, 128.50 (JCP ) 2 Hz), 127.0, 126.9, 128.5, 123.6, 120.0
(JCP ) 6 Hz), 114.2 (aryl carbons), 35.4 (2JCP ) 36 Hz, IrCH2Ph),
2
31P{1H} NMR (CD2Cl2, 202.5 MHz): δ -50.9 (d JPP′ ) 20 Hz,
of d 2JCP′′ ) 10 Hz), -51.2 (br m), -51.6 (br m). Anal. Calcd (%)
for C28H43N2SiP3IrCl: C, 43.69, H, 5.63, N, 3.64. Found: C, 43.74,
H, 5.55, N, 3.62. IR (cm-1): νIrH 2022.
(κ1-NSiN)Ir(H)(Me)(PMe3)3 (15). A 10 mL C6H6 solution of
Qn2SiHMe (0.059 g, 0.20 mmol) was added dropwise to a 5 mL
C6H6 solution of (PMe3)4IrMe (0.10 g, 0.20 mmol) at room
temperature. The red reaction mixture was allowed to stir at room
temperature for 8 h before all volatiles were removed under vacuum,
leaving an oily, orange-red residue. This residue was dissolved in
approximately 8 mL of diethyl ether and filtered through a glass
fiber filter. The red diethyl ether solution was concentrated to 1
mL and cooled to -30 °C for several days. An orange, crystalline
1
solid was obtained in 71% yield (0.10 g, 0.14 mmol). H NMR
(C6D6, 500 MHz): δ 8.73-8.64 (m, 3 H, ArH), 8.52 (d JHH ) 7.2
Hz, of d JHH ) 1.2 Hz, 1 H, ArH), 7.65 (d JHH ) 8.0 Hz, 2 H,
ArH), 7.46 (m, 2 H, ArH), 7.38 (t JHH ) 7.2 Hz, 1 H, ArH), 7.25
(t JHH ) 7.2 Hz, 1 H, ArH), 6.81 (d JHH ) 8.0 Hz, of d JHH ) 4.0
Hz, 1 H, ArH), 6.77 (d JHH ) 8.0 Hz, of d JHH ) 4.0 Hz, 1 H,
ArH), 1.89 (d 2JHP ) 2.4 Hz, 3 H, SiCH3), 1.28 (d 2JHP ) 7.2 Hz,
6.1 (SiCH3). 29Si{1H} NMR (C6D6, 99 MHz): δ -18.6 (d, 2JSiP
)
3 Hz). 31P{1H} NMR (C6D6, 162 MHz): δ 38.3 (s). Anal. Calcd
(%) for C44H37N2SiPClIr: C, 60.02, H, 4.24, N, 3.18. Found: C,
59.63, H, 4.21, N, 2.80.
2
9 H, P(CH3)3), 1.15 (d JHP′ ) 7.2 Hz, 9 H, P′(CH3)3), 1.08 (d
3JHP′′ ) 7.6 Hz, 9 H, P′′(CH3)3), 0.247 (m, 3 H, IrCH3), -11.3 (d
2
2JHP′ ) 131 Hz, of vt JHP ≈ 17 Hz, 1 H, IrH). 13C{1H} NMR
(NSiN)Ir(H)Cl(PMe3) (13). To a 10 mL THF solution of
(NSiN)Ir(H)Cl(coe) (0.27 g, 0.48 mmol) was slowly added a 5 mL
THF solution of PMe3 (55 µL, 0.53 mmol). After stirring for 12 h,
the reaction solution was evaporated to dryness. The remaining
yellow residue was then dissolved in 10 mL of THF and filtered
through Celite. The resulting solution was concentrated to a volume
of approximately 3 mL. Cooling the THF solution to -30 °C
produced a yellow, crystalline solid in 67% yield (0.17 g, 0.32
(C6D6, 125 MHz): δ 153.8, 153.6, 146.8, 146.7, 139.5, 138.9, 136.1,
135.9, 128.73, 128.71, 126.71, 126.67, 126.0, 125.9, 119.6, 119.2
(aryl carbons), 25.04 (d 2JCP ) 28 Hz, of t 3JCP ) 4.2 Hz, P(CH3)3),
2
3
3
21.2 (d JCP ) 23 Hz, of d JCP ) 3.2 Hz, of d JCP ) 2.0 Hz,
2
3
3
P′(CH3)3), 20.5 (d JCP ) 25 Hz, of d JCP ) 5.7 Hz, of d JCP
)
2.6 Hz, P′′(CH3)3), 8.23 (m, SiCH3). 29Si{1H} NMR (C6D6, 99
MHz): δ -9.4 (m). 31P{1H} NMR (C6D6, 162 MHz): δ -59.6
1
2
2
mmol). H NMR (CD2Cl2, 500 MHz): δ 10.71 (m, 1 H, ArH),
(br m), -60.6 (d JPP′ ) 17 Hz), -62.7 (d JPP′ ) 17 Hz). Anal.
Calcd (%) for C29H46N2SiP3Ir: C, 47.33, H, 6.30, N, 3.81. Found:
C, 47.69, H, 6.60, N, 3.78. IR (cm-1): νIrH 2027 (br m).
10.36 (m, 1 H, ArH), 8.11 (m, 4 H, ArH), 7.65 (d JHH ) 14 Hz, of
d JHH ) 8.0 Hz, of d JHH ) 1.5 Hz, 2 H, ArH), 7.49 (m, 2 H,
ArH), 7.38 (d JHH ) 8.0 Hz, of d JHH ) 5.0 Hz, 1 H, ArH), 7.32
(d JHH ) 8.0 Hz, of d JHH ) 5.0 Hz, 1 H, ArH), 1.30 (d JHP ) 10
(NSiN)Ir(H)(OTf)(PPh3) (16). (1) To an aluminum foil-covered
100 mL Schlenk flask equipped with a stir bar were added AgOTf
(0.070 g, 0.27 mmol) and (NSiN)Ir(H)(Cl)(PPh3) (0.20 g, 0.26
mmol). To this, 15 mL of THF was added, and the reaction mixture
was stirred at ambient temperature for 12 h. Then, the reaction
mixture was filtered through Celite, and the resulting yellow solution
was evaporated to dryness in Vacuo. Recrystallization of the product
in 5 mL of C6H6 with a small amount of THF (0.5 mL) afforded
a yellow, crystalline solid in 68% yield (0.16 g, 0.18 mmol).
2
Hz, 9 H, P(CH3)3), 1.15 (s, 3 H, SiCH3), -19.6 (d JHP ) 22 Hz,
1 H, IrH). 13C{1H} NMR (CD2Cl2, 125 MHz): δ 155.1, 154.6,
153.8, 152.2, 149.3, 148.3, 137.6, 137.5, 134.8, 134.5, 129.4, 129.3
(d JCP ) 1.2 Hz), 128.1, 128.0, 127.5, 127.4, 122.2, 122.1 (d JCP
) 2.4 Hz) (aryl carbons), 19.1 (d JCP ) 40 Hz, PCH3), -4.4
(SiCH3). 29Si{1H} NMR (CD2Cl2, 99 MHz): δ 0.85 (2JSiP ) 13
Hz). 31P{1H} NMR (CD2Cl2, 162 MHz): δ -40.3 (s). Anal. Calcd

5568 Organometallics, Vol. 26, No. 23, 2007
Sangtrirutnugul and Tilley
(2) Alternatively, 16 can be generated from addition of a 3 mL
CH2Cl2 solution of PPh3 (0.037 g, 0.16 mmol) to a 5 mL CH2Cl2
solution of 1 (0.12 g, 0.16 mmol). After 2 h of stirring at room
temperature, the solution was evaporated to dryness under vacuum.
Recrystallization from a solvent mixture of C6H6 and THF afforded
16 in 84% yield (0.12 g, 0.13 mmol). 1H NMR (THF-d8, 500
MHz): δ 10.04 (m, 1 H, ArH), 9.51 (d JHH ) 5.0 Hz, 1 H, ArH),
8.34 (d JHH ) 7.0 Hz, 1 H, ArH), 8.13 (d JHH ) 8.5 Hz, of d JHH
) 1.0 Hz, 1 H, ArH), 8.09 (d JHH ) 7.0 Hz, of d JHH ) 1.0 Hz, 1
H, ArH), 7.86 (d JHH ) 7.0 Hz, of d JHH ) 1.2 Hz, 1 H, ArH),
7.80 (d JHH ) 8.0 Hz, 1 H, ArH), 7.67 (m, 1 H, ArH), 7.52 (m, 2
H, ArH), 7.46-7.41 (m, 7 H, ArH), 7.29 (m, 1 H, ArH), 7.20 (m,
3 H, ArH), 7.12 (m, 6 H, ArH), 0.470 (s, 3 H, SiCH3), -16.5 (d
2JHP ) 19 Hz, 1 H, IrH). 13C{1H} NMR (CD2Cl2, 125 MHz): δ
153.2, 153.0, 151.9, 151.8, 144.0, 143.5, 139.6, 139.1, 135.6 (JCP
) 3.8 Hz), 133.7 (JCP ) 10 Hz), 131.0 (JCP ) 2.5 Hz), 130.7 (JCP
) 58 Hz), 129.7, 129.5, 129.4, 129.3, 128.7 (JCP ) 11 Hz), 128.5,
128.2, 123.0, 122.9 (aryl carbons), -5.4 (SiCH3). 19F NMR (THF-
d8, 376.5 MHz): δ -77.8 (s). 29Si{1H} NMR (THF-d8, 99 MHz):
crystallographic software package of the Molecular Structure
Corporation, using direct methods or Patterson methods and
expanded with Fourier techniques. Unless stated otherwise, all non-
hydrogen atoms were refined anisotropically, and the hydrogen
atoms were placed in calculated positions but not refined. The
function minimized in the full-matrix least-square refinement was
∑w(|Fo| - |Fc|).2 The weighting scheme was based on counting
statistics and included a p-factor to downweight the intense
reflections. Crystallographic data are summarized in the Supporting
Information.
For 2. Crystals were grown from a diethyl ether solution of 2 at
-30 °C.
For 5. Crystals were grown by layering diethyl ether onto a
dichloromethane solution of 5 at room temperature.
For 14‚CH2Cl2. Crystals were grown by layering pentane onto a
dichloromethane solution of 14 at room temperature. One molecule
of CH2Cl2 was found in the asymmetric unit cell. The Ir-H group
could not be located in the difference Fourier map.
For 15‚0.5Et2O. Crystals were grown from a concentrated diethyl
ether solution of 15 at -30 °C. One-half molecule of Et2O was
found in the asymmetric unit cell with the oxygen atom on an
inversion center. This molecule was modeled with a half-occupancy
oxygen and two full-occupancy carbons. The other atoms of the
diethyl ether molecule were generated using a full symmetry
expansion. The Ir-H ligand was located in the difference Fourier
map and positionally refined.
2
δ -6.1 (d, JSiP ) 11 Hz). 31P{1H} NMR (THF-d8, 162 MHz): δ
9.3 (br s). Anal. Calcd (%) for C38H31N2SiPO3SF3Ir: C, 50.49, H,
3.46, N, 3.10. Found: C, 50.77, H, 3.48, N, 3.02. IR (cm-1): νIrH
2120 (w).
X-ray Crystallography. General Considerations. The single-
crystal X-ray analyses of compounds 2, 5, 14, and 15 were carried
out at the UC Berkeley CHEXRAY crystallographic facility. All
measurements were made on a Bruker SMART or APEX CCD
area detector with graphite-monochromated Mo KR radiation (λ
) 0.71069 Å). Crystals were mounted on capillaries or a Kapton
loop with Paratone N hydrocarbon oil and held in a low-temperature
N2 stream during data collection. Frames were collected using ω
scans at 0.3° increments, using exposures of 10 s (2), 15 s (14), or
30 s (5 and 15). Cell constants and an orientation matrix for data
collection were obtained from a least-square refinement using the
measured positions of reflections in the range 3.5° < 2θ < 52.7°.
The frame data were integrated by the program SAINT (SAX Area-
Detector Integration Program; V4.024; Siemens Industrial Automa-
tion, Inc.: Madison, WI, 1995) and corrected for Lorentz and
polarization effects. Data were analyzed for agreement and possible
absorption using XPREP. Empirical absorption corrections based
on comparison of redundant and equivalent reflections were applied
using SADABS. The structures were solved using the teXsan
Acknowledgment. We thank Dr. Fred Hollander and Dr.
Alan Oliver of the UC Berkeley CHEXRAY facility for
assistance with X-ray crystallography, Dr. Urs Burckhardt, Dr.
Rudi Nunlist, and Dr. Herman van Halbeek for implementation
of 29Si NMR experiments, and Dr. Ulla Andersen for carrying
out mass spectrometry measurements. This work was supported
by the National Science Foundation under Grant No. CHE-
0649583.
Supporting Information Available: Text describing complete
X-ray experimental details, ORTEP plots, and structural data for
2, 5, 14, and 15. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM700494Q