Synthesis and characterization of IrH2{Si(OTf)Ph2}(TFB)(PR3) (PR3 = PiPr3, PCy3): First base-stabilized silylene complexes of iridium

Article abstract of DOI:10.1021/om9508896

The reactions of H₂SiPh₂ with the triflato complexes Ir(OTf)(TFB)(PR₃) afford the base-stabilized silylene complexes IrH₂{Si(OTf)Ph₂}(TFB)(PR₃) (TFB = tetrafluorobenzobarrelene; PR₃ = PⁱPr₃, PCy₃). The single-crystal X-ray structural analysis of IrH₂{Si(OTf)-Ph₂}(TFB)(PⁱPr₃) has been performed. The distances Ir-Si (2.337(2) ?) and Si-O (1.790(5) ?) as well as the summation of angles at silicon, ignoring the Si-OTf bond (343.5°), are in agreement with the partial unsaturated character of the base-stabilized silylene ligand.

Full text of DOI:10.1021/om9508896

Organometallics 1996, 15, 2185-2188
2185
Syn th esis a n d Ch a r a cter iza tion of
Ir H2{Si(OTf)P h 2}(TF B)(P R3) (P R3 ) P iP r 3, P Cy3): F ir st
Ba se-Sta bilized Silylen e Com p lexes of Ir id iu m
Wanzhi Chen, Andrew J . Edwards, Miguel A. Esteruelas,* Fernando J . Lahoz,
Montserrat Oliva´n, and Luis A. Oro*
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
Received November 14, 1995X
Summary: The reactions of H2SiPh2 with the triflato
complexes Ir(OTf)(TFB)(PR3) afford the base-stabilized
silylene complexes IrH2{Si(OTf)Ph2}(TFB)(PR3) (TFB )
tetrafluorobenzobarrelene; PR3 ) PiPr3, PCy3). The
single-crystal X-ray structural analysis of IrH2{Si(OTf)-
Ph2}(TFB)(PiPr3) has been performed. The distances Ir-
Si (2.337(2) Å) and Si-O (1.790(5) Å) as well as the
summation of angles at silicon, ignoring the Si-OTf
bond (343.5°), are in agreement with the partial unsat-
urated character of the base-stabilized silylene ligand.
For several years, we have been exploring the reactiv-
ity of square-planar iridium(I) complexes toward si-
lanes.9 Thus, recently, we have observed that the
reactions of the π-alkyne complexes Ir(acac)(η2-CH3O2-
CC≡CCO2CH3)(PR3) with H2SiPh2 lead to Ir(acac)-
{C[CH(OCH3)OSiPh2]dCHCO2CH3}(PR3) (PR3 ) PiPr3,
PCy3), which are a net result of a transformation
involving addition of one Si-H bond across the CdO
bond and a second across the alkyne triple bond. In
these compounds the bonding situation in the Ir-Si-O
sequence could be described as a intermediate state
between metal-silylene stabilized by an oxygen base
and a tetrahedral silicon.10
As a continuation of our work in this field, we have
now carried out the reactions of square-planar iridium-
(I) complexes Ir(OTf)(TFB)(PR3) (TFB ) tetrafluoroben-
zobarrelene; PR3 ) PiPr3, PCy3) with H2SiPh2. During
this study, we have isolated the derivatives IrH2{Si-
(OTf)Ph2}(TFB)(PR3), which are the first base-stabilized
iridium-silylene complexes. In this note, we report
their syntheses and structural characterization.
In tr od u ction
The development of transition-metal base-stabilized
silylene chemistry reached a significant milestone in
1987, when Tilley1 and Zybill2 reported the synthesis
and crystal structures of the base-stabilized silylene
derivatives [Ru(η5-C5Me5){Si(NCCH3)Ph2}(PMe3)2]BPh4
and Fe{Si(HMPA)(OtBu)2}(CO)4 (HMPA ) hexameth-
ylphosphoric triamide), respectively. Over the past few
years well-characterized silylene complexes of Cr,3 Mo,3g
W,3c Mn,3egh,4 Re,5 Fe,2,3acegh,4b,6 Ru,1,7 Os,8 and Co3 have
been reported. However, no iridium-silylene deriva-
tives are known.
Resu lts a n d Discu ssion
X Abstract published in Advance ACS Abstracts, April 1, 1996.
(1) Straus, D. A.; Tilley, T. D.; Rheingold, A. L.; Geib, S. J . J . Am.
Chem. Soc. 1987, 109, 5872.
The base-stabilized silylene complexes IrH2{Si(OTf)-
Ph2}(TFB)(PR3) (PR3 ) PiPr3 (6), PCy3 (7)) can be
prepared via the reaction sequence shown in Scheme
1. On treatment with PiPr3 and PCy3, the bis(tetrafluo-
robenzobarrelene)iridium(I) compound 1 affords the
square-planar derivatives 2 and 3. The reactions of
these compounds with AgOTf lead to complexes 4 and
5, which react with the stoichiometric amount of diphe-
nylsilane, in toluene at room temperature, to give yellow
solutions, from which the base-stabilized silylene de-
rivatives 6 and 7 are separated as white solids in 39%
(6), and 68% (7) yield, respectively, by addition of
hexane.
Complexes 6 and 7 were characterized by elemental
analysis and IR and 1H and 31P{1H} NMR spec-
troscopies. Complex 6 was further characterized by an
X-ray crystallographic study. The molecular structure
of 6 is presented in Figure 1. Selected bond distances
and angles are listed in Table 1.
(2) Zybill, C.; Mu¨ller, G. Angew. Chem., Int. Ed. Engl. 1987, 26, 669.
(3) (a) Zybill, C.; Mu¨ller, G. Organometallics 1988, 7, 1368. (b)
Probst, R.; Leis, C.; Gamper, S.; Herdtweck, E.; Zybill, C.; Auner, N.
Angew. Chem., Int. Ed. Engl. 1991, 30, 1132. (c) Leis, C.; Wilkinson,
D. L.; Handwerker, H.; Zybill, C.; Mu¨ller, G. Organometallics 1992,
11, 514. (d) Handwerker, H.; Paul, M.; Blu¨mel, J .; Zybill, C. Angew.
Chem., Int. Ed. Engl. 1993, 32, 1313. (e) Corriu, R. J . P.; Lanneau, G.
F.; Chauhan, B. P. S. Organometallics 1993, 12, 2001. (f) Handwerker,
H.; Leis, C.; Probst, R.; Bissinger, P.; Grohmann, A.; Kiprof, P.;
Herdtweck, E.; Blu¨mel, J .; Auner, N.; Zybill, C. Organometallics 1993,
12, 2162. (g) Chauhan, B. P. S.; Corriu, J . R. P.; Lanneau, G. F.; Priou,
C.; Auner, N.; Handwerker, H.; Herdtweck, E. Organometallics 1995,
14, 1657. (h) Corriu, R. J . P.; Chauhan, B. P. S.; Lanneau, G. F.
Organometallics 1995, 14, 1646.
(4) (a) Takeuchi, T.; Tobita, H.; Ogino, H. Organometallics 1991,
10, 835. (b) Corriu, R.; Lanneau, G.; Priou, C. Angew. Chem., Int. Ed.
Engl. 1991, 30, 1130.
(5) Lee, K. E.; Arif, A. M.; Gladysz, J . A. Chem. Ber. 1991, 124, 309.
(6) (a) Ueno, K.; Tobita, H.; Shimoi, M.; Ogino, H. J . Am. Chem.
Soc. 1988, 110, 4092. (b) Zybill, C.; Wilkinson, D. L.; Mu¨ller, G. Angew.
Chem., Int. Ed. Engl. 1988, 27, 583. (c) Zybill, C.; Wilkinson, D. L.;
Leis, C.; Mu¨ller, G. Angew. Chem., Int. Ed. Engl. 1989, 28, 203. (d)
Tobita, H.; Ueno, K.; Shimoi, M.; Ogino, H. J . Am. Chem. Soc. 1990,
112, 3415. (e) Leis, C.; Zybill, C.; Lachmann, J .; Mu¨ller, G. Polyhedron
1991, 10, 1163. (f) Koe, J . R.; Tobita, H.; Ogino, H. Organometallics
1992, 11, 2479. (g) Ueno, K.; Tobita, H.; Ogino, H. J . Organomet. Chem.
1992, 430, 93. (h) Ueno, K.; Ito, S.; Endo, K.; Tobita, H.; Inomata, S.;
Ogino, H. Organometallics 1994, 13, 3309.
The coordination geometry around the iridium atom
could be rationalized as derived from a highly distorted
(7) (a) Straus, D. A.; Zhang, C.; Quinbita, G. E.; Grumbine, S. D.;
Heyn, R. H.; Tilley, T. D.; Rheingold, A. L.; Geib, S. J . J . Am. Chem.
Soc. 1990, 112, 2673. (b) Grumbine, S. D.; Chadha, R. K.; Tilley, T. D.
J . Am. Chem. Soc. 1992, 114, 1518. (c) Tobita, H.; Wada, H.; Ueno, K.;
Ogino, H. Organometallics 1994, 13, 2545. (d) Grumbine, S. K.; Straus,
D. A.; Tilley, T. D.; Rheingold, A. L. Polyhedron 1995, 14, 127.
(8) Woo, L. K.; Smith, D. A.; Young, V. G., J r. Organometallics 1991,
10, 3977.
(9) (a) Ferna´ndez, M. J .; Esteruelas, M. A.; Covarrubias, M.; Oro,
L. A.; Apreda, M. C.; Foces-Foces, C.; Cano, F. H. Organometallics
1989, 8, 1158. (b) Esteruelas, M. A.; Nu¨rnberg, O.; Oliva´n, M.; Oro, L.
A.; Werner, H. Organometallics 1993, 12, 3264. (c) Esteruelas, M. A.;
Lahoz, F. J .; Oliva´n, M.; On˜ate, E.; Oro, L. A. Organometallics 1994,
13, 4246.
(10) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Rodr´ıguez,
L. Organometallics 1995, 14, 263.
0276-7333/96/2315-2185$12.00/0 © 1996 American Chemical Society

2186 Organometallics, Vol. 15, No. 8, 1996
Notes
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for th e Com p lex
Ir H2{Si(OTf)P h 2}(TF B)(P iP r 3) (6)
Ir-P
2.355(2)
2.239(7)
2.227(7)
1.37(1)
1.790(5)
1.870(7)
Ir-Si
2.337(2)
2.229(7)
2.214(7)
1.38(1)
Ir-C(2)
Ir-C(5)
C(2)-C(3)
Si-O(1)
Si-C(31)
Ir-C(3)
Ir-C(6)
C(5)-C(6)
Si-C(21)
1.877(7)
P-Ir-Si
129.51(7)
119.0(2)
95.8(3)
O(1)-Si-Ir
C(31)-Si-Ir
O(1)-Si-C(31)
114.8(2)
115.9(2)
99.3(3)
C(21)-Si-Ir
O(1)-Si-C(21)
C(31)-Si-C(21)
108.6(3)
(COD)(AsPh3) (COD ) 1,5-cyclooctadiene, 2.414(2) Å),11
IrH2(SiMe2Ph)(CO){P(p-tol)3}2 (2.414(2) Å),12 IrH(Ph2-
SiC6H4)(PMe3)3 (2.404(3) Å),13 IrH(SiMe2Cl)2(CO)(dppe)
(dppe ) 1,2-bis(diphenylphosphino)ethane, 2.396(2) Å),
and IrH(SiEtF2)2(CO)(dppe) (2.360(10) Å).14 The si-
lylene character of 6 is also supported by the relatively
long Si-O(1) bond length of 1.790(5) Å. Typical Si-O
single bonds in silyl compounds normally fall in the
range 1.63-1.66 Å,15 whereas metal-silylene complexes
stabilized by oxygen bases have Si-O distances between
1.68 and 1.85 Å. The Si-O(1) distance in 6 is longer
than the related bond length reported for the complexes
Fe{Si(HMPA)Cl2}(CO)4 (1.683(3) Å),3c Cr{Si(HMPA)-
Cl2}(CO)5 (1.690(2) Å),3c Fe{Si(HMPA)Me2}(CO)4 (1.735(3)
Å),6c Cr{Si(HMPA)Me2}(CO)5 (1.743(2) Å),3c Fe{Si-
(HMPA)(StBu)2}(CO)4 (1.734(2) Å),6e Fe{Si(HMPA)(Ot-
Bu)2}(CO)4 (1.730(3) Å),2 and Ru(η5-C5Me5){Si[S(Tol-p)]-
(OTf)2}(PMe3)2 (1.765(8) Å)7d but shorter than those
found in Os(TTP){Si(THF)Et2} (TTP ) meso-tetra-p-
tolylporphyrin, 1.82(2) Å),8 Ru(η5-C5Me5){Si(OTf)Ph2}-
(PMe3)2 (1.853(5) Å),7a and Ru(η5-C5Me5){Si[S(Tol-p)]2-
(OTf)}(PMe3)2 (1.856(5) Å).7d
Figu r e 1. Molecular structure of IrH2{Si(OTf)Ph2}(TFB)(Pi-
Pr3) (6).
Sch em e 1
The bond angles at silicon fall into four distinct
groups: the C(21)-Si-Ir angle (119.0(2)°) is close to the
standard sp2 angle (120°), while the C(31)-Si-C(21)
(108.6(3)°) is close to a tetrahedral angle of 109°, and
the O(1)-Si-Ir (114.8(2)°) and C(31)-Si-Ir (115.9(2)°)
angles lie in between, while O(1)-Si-C(21) (95.8(3)°)
and O(1)-Si-C(31) (99.3(3)°) are noticeably smaller. It
has previously been proposed that for a base-stabilized
silylene compound the summation of angles at silicon,
ignoring the Si-base bond, should be between 329 and
360°.3,7 For complex 6 the summation of the angles
C(21)-Si-Ir, C(13)-Si-Ir, and C(21)-Si-C(31) gives
a value of 343.5°, which is very close to the arithmetic
mean between the tetrahedral and trigonal values
(344.5°) and agrees well with those reported for [Ru-
(η5-C5Me5){Si(NCCH3)Me2}(PMe3)2]BPh4 (344°)7d but is
greater than those reported for M{Si(HMPA)R2}(CO)n
(M ) Fe, n ) 4; M ) Cr, n ) 5; 337-342°)3c and Ru-
(η5-C5Me5){Si(OTf)R2}(PMe3)2 (R ) S(p-Tol) (334°), Ph
(341°))7d and smaller than that calculated for [Ru(η5-
C5Me5){Si(NCCH3)Ph2}(PMe3)2]BPh4 (352°).7d
octahedron with the triisopropylphosphine and the
silylene ligands occupying pseudo-trans positions (P-
Ir-Si ) 129.51(7)°), at opposite sites of an ideal coor-
dination plane defined by the two cis-hydrido ligands
(H(1a)-Ir-H(1b) ) 97(4)°) and the chelate diolefinic
molecule.
The small Si-Ir-P angle (129.51(7)°) may be due to
different steric requirements, relatively small for the
The most conspicuous features of the structure are
the structural parameters related to the silicon atom,
which suggest the presence of partial unsaturated
character, and the small Si-Ir-P angle.
(11) Ferna´ndez, M. J .; Esteruelas, M. A.; Oro, L. A.; Apreda, M. C.;
Foces-Foces, C.; Cano, F. H. Organometallics 1987, 6, 1751.
(12) Rappoli, B. J .; J anik, T. S.; Churchill, M. R.; Thompson, J . S.;
Atwood, J . D. Organometallics 1988, 7, 1939.
As expected for a base-stabilized silylene-iridium(III)
complex, the Ir-Si distance of 2.337(2) Å is significantly
shorter than those determined previously for the six-
coordinate silyliridium(III) compounds IrH2(SiEt3)-
(13) Aizenberg, M.; Milstein, D. Angew. Chem., Int. Ed. Engl. 1994,
33, 317.
(14) Hays, M. K.; Eisenberg, R. Inorg. Chem. 1991, 30, 2623.
(15) Wiberg, N.; Wagner, G.; Mu¨ller, G.; Riede, J . J . Organomet.
Chem. 1984, 271, 381.

Notes
Organometallics, Vol. 15, No. 8, 1996 2187
hydridos and comparatively large for the diene, PiPr3,
and silylene ligands. Angular distortions in hydrido
complexes are not unusual. We note that in the
complex IrH2(SnPh3)(TFB)(PCy3) the angle between the
stannyl and phosphine ligands is 129.46(3)°.16 A similar
observation has been reported for the silyl compound
IrH2(SiEt3)(COD)(AsPh3), in which the major deviation
from the ideal octahedron geometry arises from the Si-
Ir-As angle (133.40(4)°).11 For the complex IrH2-
(SnCl3)(PPh3)3 the angle P-Ir-P involving two chemi-
cally equivalent phosphine groups, which are pseudo-
trans to each other, is 145.95(9)°.17 Values of about 150°
have been also reported for the related angle in the
complexes mer-IrH3(PPh3)3,8 [(PPh3)Au(µ-H)IrH2(P-
Ph3)3]+,19 mer-[IrH2(CO)(PPh3)3]+,20 and [IrH2(PPh3)2-
(C4H8S)2]+.21
(TFB). Following this is attack of the silylene group by
the [OTf]- anion to form the unsaturated dihydrido
IrH2{Si(OTf)Ph2}(TFB), which by coordination of the
phosphine ligand should give 6 and 7. A similar
mechanism has previously been proposed for the forma-
tion of IrH2{Si[OC(O)CH3]Ph2}(TFB)(PR3)9b and IrH2-
{Si(OR)Ph2}(CO)2(PCy3).9c
In conclusion, the reactions of Ir(OTf)(TFB)(PR3) with
H2SiPh2 afford IrH2{Si(OTf)Ph2}(TFB)(PR3) (PR3 ) Pi-
Pr3, PCy3). The single-crystal X-ray structural analysis
of IrH2{Si(OTf)Ph2}(TFB)(PiPr3) indicates that the struc-
tural parameters at the silicon atom agree well with
those previously reported for types of silyl compounds
generally known as base-stabilized silylene complexes.
Exp er im en ta l Section
In agreement with the structure shown in Figure 1
the IR spectra of 6 and 7 in Nujol contain one absorption
at 2155 (6) and 2145 cm-1 (7), attributable to ν(Ir-H).
In the 1H NMR spectra in toluene-d8 the hydrido
resonances appear as a doublet at -15.16 (6) and
-14.85 ppm (7) with P-H coupling constants of 18.9
and 18.3 Hz, respectively. At room temperature, the
spectra contain two resonances from the diolefin, one
due to the aliphatic protons at approximately 4.8 ppm
and the other, due to the olefinic protons, at about 3.2
ppm. At -55 °C, the spectra show two aliphatic and
two olefinic resonances, in agreement with the arrange-
ment of ligands around the iridium atom (Figure 1).
This behavior suggests that, in solution, the complexes
6 and 7 possess rigid structures only at low tempera-
ture. At room temperature an intramolecular exchange
process takes place, which involves the relative positions
of the atoms of the diolefin, similarly to that observed
for the dihydrido-silyl and dihydrido-stannyl com-
plexes IrH2(SiPh3)(TFB)(PCy3) and IrH2(SnPh3)(TFB)-
(PCy3). The fluxional process could proceed via five-
coordinate intermediates, resulting from the dissociation
of the phosphine ligand or of one arm of the chelating
tetrafluorobenzobarrelene diolefin.16 The 31P{1H} NMR
spectra show singlets at 23.0 (6) and 7.1 ppm (7), along
with the satellites due to the 29Si isotope. In accordance
with the pseudo-trans positions of the silylene and
phosphine ligands, the values of the P-29Si coupling
constants are 83.5 (6) and 82.4 Hz (7). Under off-
resonance conditions, both singlets are split into triplets
due to the P-H coupling.
All reactions were carried out under argon atmosphere using
standard Schlenk techniques. Solvents were dried using
appropiate drying agents and freshly distilled under argon
before use. Complex IrCl(TFB)2 (1) was prepared by a
published method.23
1H and 31P{1H} NMR spectra were recorded on either a
Varian UNITY 300 or on a Bruker 300 AXR spectrophotom-
eter. Chemical shifts are expressed in ppm upfield from Me4-
Si (1H) and 85% H3PO4 (31P{1H}). Coupling constants are
given in hertz. IR data were recorded on a Perkin-Elmer 783
or on a Nicolet 550 spectrophotometer. Elemental analyses
were carried out with a Perkin-Elmer 2400 CHNS/O mi-
croanalyzer.
P r ep a r a tion of Ir Cl(TF B)(P iP r 3) (2). A suspension of 1
(100 mg, 0.147 mmol) in acetone (10 mL) was treated with
PiPr3 (28 µL, 0.147 mmol). The resulting solution was stirred
for 15 min at room temperature. After concentration of the
solution to dryness, hexane was added to afford an orange
solid. The solution was decanted, and the solid was washed
with hexane and dried in vacuo; yield 73 mg (81.5%). Anal.
Calcd for C21H27ClF4IrP: C, 41.07; H, 4.43. Found: C, 40.73;
H, 4.13. IR (Nujol, cm-1): ν(Ir-Cl) 320 (m). 1H NMR (300
MHz, C6D6, 20 °C): δ 5.50 (br, 2H, -CH), 4.18 (br, 2H, dCH),
2.27 (m, 5H, dCH and PCHCH3), 1.31 (dd, J H-H ) 7.3, J P-H
)
13.7, 18H, PCHCH3). 31P{1H} NMR (121.4 MHz, C6D6): δ 28.8
(s).
P r ep a r a tion of Ir Cl(TF B)(P Cy3) (3). This compound was
prepared analogously to 2, starting from IrCl(TFB)2 (100 mg,
0.147 mmol) and PCy3 (41.2 mg, 0.147 mmmol). Compound 2
was isolated as an orange solid: yield 101 mg (93%). Anal.
Calcd for C30H39ClF4IrP: C, 49.07; H, 5.35. Found: C, 49.28;
H, 5.74. IR (Nujol, cm-1): ν(Ir-Cl) 325 (m). 1H NMR (300
MHz, C6D6, 20 °C): δ 5.16 (br, 2H, -CH), 4.05 (br, 2H, dCH),
2.00 (br, 2H, dCH), 1.98-1.09 (m, 33H, PCy3). 31P{1H} NMR
(121.4 MHz, C6D6): δ 17.7 (s).
P r ep a r a tion of Ir (OTf)(TF B)(P iP r 3) (4). A solution of 2
(100 mg, 0.163 mmol) in acetone (10 mL) was treated with
AgOTf (42 mg, 0.163 mmol). After stirring for 1 h in the dark,
the suspension was filtered, and the solution was concentrated
to ca. 0.5 mL. Hexane was added to afford a yellow solid. The
The formation of 6 and 7 probably involves the initial
oxidative addition of H2SiPh2 to 4 and 5 to give hy-
drido-silyl intermediates of the type IrH(OTf)(SiHPh2)-
(TFB)(PR3).22 According to general trend shown for
these compounds to release phosphine, the dissociation
of the phosphine ligands from the hydrido-silyl inter-
mediates could lead to the unsaturated species IrH-
(SiHPh2)(OTf)(TFB), which by an R-elimination reaction
should give the silylene derivative IrH2(dSiPh2)(OTf)-
(22) Most of the silyl complexes of iridium(III) previously reported
have been obtained by oxidative addition of HSiR3 to iridium(I)
compounds. See: (a) J ohnson, C. H.; Eisenberg, R. J . Am. Chem. Soc.
1985, 107, 6531. (b) Rappoli, B. J .; J anik, T. S.; Churchill, M. R.;
Thompson, J . S.; Atwood, J . D. Organometallics 1988, 7, 1939. (c) Lwo,
X.-L.; Crabtree, R. H. J . Am. Chem. Soc. 1989, 111, 2527. (d) Rappoli,
B. J .; McFarland, J . M.; Thompson, J . S.; Atwood, J . D. Coord. Chem.
1990, 21, 147. (e) Hays, M. K.; Eisenberg, R. Inorg. Chem. 1991, 30,
2623. (f) Schubert, U. Transition Met. Chem. 1991, 16, 136. (g) Tanke,
R. S.; Crabtree, R. H. Organometallics 1991, 10, 415. (h) Hostetler,
M. J .; Bergman, R. G. J . Am. Chem. Soc. 1992, 114, 7629. (i) Cleary,
B. P.; Eisenberg, R. Organometallics 1992, 11, 2335.
(16) Esteruelas, M. A.; Lahoz, F. J .; Oliva´n, M.; On˜ate, E.; Oro, L.
A. Organometallics 1995, 14, 3486.
(17) Kretschmer, M.; Pregosin, P. S.; Albinati, A.; Togni, A. J .
Organomet. Chem. 1985, 281, 365.
(18) Clark, G. R.; Skelton, B. W.; Waters, T. N. Inorg. Chim. Acta.
1975, 12, 235.
(19) Lehner, H.; Matt, D.; Pregosin, P. S.; Venanzi, L. M.; Albinati,
A. J . Am. Chem. Soc. 1982, 104, 6825.
(20) Bird, P.; Harrod, J . F.; Than, K. A. J . Am. Chem. Soc. 1974,
96, 1222.
(21) Sa´nchez-Delgado, R. A.; Herrera, V.; Bianchini, C.; Masi, D.;
Mealli, C. Inorg. Chem. 1993, 32, 3766.
(23) Uso´n, R.; Oro, L. A.; Carmona, D.; Esteruelas, M. A.; Foces-
Foces, C.; Cano, F. H.; Garc´ıa-Blanco, S. J . Organomet. Chem. 1983,
254, 249.

2188 Organometallics, Vol. 15, No. 8, 1996
Notes
solution was decanted, and the solid was washed with hexane
and dried in vacuo; yield 90.2 mg (76%). Anal. Calcd for
were obtained from a toluene/pentane solution. An oil-coated
rapidly cooled colorless crystalline rectangular block was
mounted directly from solution.24 Crystal and collection
data: orthorhombic space group Pbca (No. 61); a ) 15.798(4),
b ) 13.527(1), c ) 32.403(2) Å; V ) 6925(2) Å3 (from 50
reflections 10 e 2θ e 25°); Z ) 8, dcalcd ) 1.750 g cm-3; (Mo
KR) ) 4.07 mm-1; crystal dimensions 0.45 × 0.44 × 0.31 mm;
4-circle Sto¨e AED diffractometer, Mo KR radiation (0.71073
Å), graphite-oriented monochromator; T ) 153 K; 2θ/ω scan
method, max 2θ ) 50°; 6088 reflections measured, 6070
independent reflections. Intensity data were corrected for
Lorentz and Polarization effects, and a semiempirical absorp-
tion correction (ψ scan method25 ) was applied. The structure
was solved by direct methods and conventional Fourier
techniques.26 All non-hydrogen atoms were refined anisotropic
by full-matrix least squares. The hydrides and the hydrogens
of the TFB ligand were located and freely refined isotropically.
Remaining hydrogens were fixed in idealized positions (dis-
tance C-H ) 0.96 Å). R values: R1 (Fo > 4σ(Fo), for 4657
reflections) ) 0.0388; R2 (all data) ) 0.1068; R1(F) ) Σ||Fo| -
C
22H27F7IrO3PS: C, 36.31; H, 3.74; S, 4.41. Found: C, 36.52;
H, 4.33; S, 4.13. 1H NMR (300 MHz, C6D6, 20 °C): δ 4.92 (br,
2H, -CH), 4.53 (br, 2H, dCH), 1.60 (m, 5H, dCH and
PCHCH3), 0.91 (dd, J H-H ) 7.0, J P-H ) 14.0, 18H, PCHCH3).
31P{1H} NMR (121.4 MHz, C6D6): δ 31.1 (s).
P r ep a r a tion of Ir (OTf)(TF B)(P Cy3) (5). This compound
was prepared analogously to 4, starting from 3 (100 mg, 0.135
mmol) and AgOTf (35 mg, 0.135 mmol). Compound 5 was
isolated as a deep yellow solid; yield 89 mg (77%). Anal. Calcd
for C31H39F7IrO3PS: C, 43.91; H, 4.64; S, 3.78. Found: C,
43.73; H, 5.53; S, 3.85. IR (Nujol, cm-1): νasym(SO) 1346 (s).
1H NMR (300 MHz, C6D6, 20 °C): δ 4.99 (br, 2H, -CH), 4.54
(br, 2H, dCH), 1.88 (br, 2H, dCH), 1.75-1.10 (m, 33H, PCy3).
31P{1H} NMR (121.4 MHz, C6D6): δ 19.2 (s).
P r ep a r a tion of Ir H2{Si(OTf)P h 2}(TF B)(P iP r 3) (6).
A
solution of 4 (100 mg, 0.137 mmol) in toluene (10 mL) was
treated with H2SiPh2 (27 µL, 0.137 mmol). The orange solution
became pale yellow immediately. This solution was concen-
trated to ca. 0.5 mL, and addition of hexane caused the
precipitation of a white solid. The solution was decanted, and
the solid was washed with hexane and dried in vacuo; yield
49 mg (39%). Anal. Calcd for C34H39F7IrO3PSSi: C, 44.78;
H, 4.31; S, 3.52. Found: C, 44.33; H, 4.37; S, 3.71. IR (Nujol,
cm-1): ν(Ir-H) 2155 (m), νasym(SO) 1366 (s). 1H NMR (300
MHz, C6D6, 20 °C): δ 7.95-7.15 (m, 10H, Ph), 4.77 (br, 2H,
-CH), 3.20 (s, 4H, dCH), 1.89 (m, 3H, PCHCH3), 0.79 (dd,
2
|Fc||/Σ|Fo|, R2(F2) ) x{Σw(Fo - Fc2)2/ΣwFo4}, w ) 1/[σ2(Fo2) +
(xP)2 + yP], P ) (Fo2 + 2Fc2)/3] (where x ) 0.03 and y ) 63.55).
Largest peak and hole in the final difference map: 1.129 and
-1.534 e Å-3
.
Ack n ow led gm en t. We thank the DGICYT (Project
PB92-0092, Programa de Promocio´n General del Cono-
cimiento) and the EU (Project: Selective Processes and
Catalysis Involving Small Molecules) for financial sup-
port. W.C. (Ministerio de Educacio´n y Ciencia, Spain),
A.J .E. (EU, programme Human, Capital and Mobility,
CT93-0347), and M.O. (Diputacio´n General de Arago´n)
are grateful for grants.
J H-H ) 7.0, J P-H ) 13.9, 18H, PCHCH3), -15.16 (d, J P-H
)
18.9, 2H, Ir-H). 1H NMR (300 MHz, C7D8, -55 °C): δ 4.88
(br, 1H, -CH), 4.34 (br, 1H, -CH), 3.36 (br, 2H, dCH), 2.56
(br, 2H, dCH). 31P{1H} NMR (121.4 MHz, C6D6): δ 23.0 (s
with 29Si satellites, J P-Si ) 83.5).
P r ep a r a tion of Ir H2{Si(OTf)P h 2}(TF B)(P Cy3) (7). This
compound was prepared analogously to 6, starting from 5 (100
mg, 0.118 mmol) and H2SiPh2 (23 µL, 0.118 mmmol). Com-
pound 7 was isolated as a white solid; yield 83 mg (68%). Anal.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates and thermal parameters, anisotropic thermal
parameters, experimental details of the X-ray study, and
complete bond distances and angles (7 pages). Ordering
information is given on any current masthead page.
Calcd for
C43H52F7IrO3PSSi: C, 49.99; H, 5.07; S, 3.10.
Found: C, 50.27; H, 4.94; S, 2.85. IR (Nujol, cm-1): ν(Ir-H)
2145 (m), νasym(SO) 1375 (s). 1H NMR (300 MHz, C6D6, 20
°C): δ 7.97-7.12 (m, 10H, Ph), 4.84 (br, 2H, -CH), 3.28 (br,
4H, dCH), 2.06-1.15 (m, 33H, PCy3), -14.85 (d, J P-H ) 18.3,
2H, Ir-H). 1H NMR (300 MHz, C7D8, -55 °C): δ 4.94 (br,
1H, -CH), 4.53 (br, 1H, -CH), 3.46 (br, 2H, dCH), 2.78 (br,
2H, dCH). 31P{1H} NMR (121.4 MHz, C6D6): δ 7.1 (s with
29Si satellites, J P-Si ) 82.4; triplet in off-resonance).
OM9508896
(24) Kottke, T.; Stalke, D. J . Appl. Crystallogr. 1993, 26, 615.
(25) North, A. C. T.; Phillips, D. C.; Mathews, F. S. Acta Crystallogr.
1968, A24, 351.
(26) Sheldrick, G. M. SHELXL-93, Program for Crystal Structure
Refinement; University of Go¨ttingen: Go¨ttingen, Germany, 1993.
X-r a y Str u ctu r e An a lysis of Ir H2{Si(OTf)P h 2}(TF B)-
(P iP r 3) (6). Crystals suitable for the X-ray diffraction study