Oxidative Addition of Hydrosilanes, Hydrogermane, and Hydrostannane to Cyclopentadienylcobalt(I) Bearing a Pendant Phosphane Ligand: Cyclopentadienylhydridocobalt(III) Chelate Complexes with Silyl, Germyl, and Stannyl Ligands

Article abstract of DOI:10.1021/om030581b

Oxidative addition of hydrosilanes, a hydrogermane, and a hydrostannane to the ((cyclopentadienylalkyl)phosphane)cobalt(I) chelate 1 results in the formation of cyclopentadienylhydridocobalt(III) complexes having a tethered phosphorus ligand and silyl (rac-4-rac-8), germyl (rac-10), and stannyl substituents (rac-11). The pseudo-four-coordinate complexes are chiral. The X-ray structures of 5 and 7 have been determined. Variable-temperature NMR spectra indicate racemization in solution due to reversible dissociation of the phosphorus ligand. The barrier of this process has been estimated to be in the range of 13-16 kcal/mol.

Full text of DOI:10.1021/om030581b

Organometallics 2003, 22, 5463-5467
5463
Oxid a tive Ad d ition of Hyd r osila n es, Hyd r oger m a n e, a n d
Hyd r osta n n a n e to Cyclop en ta d ien ylcoba lt(I) Bea r in g a
P en d a n t P h osp h a n e Liga n d :
Cyclop en ta d ien ylh yd r id ocoba lt(III) Ch ela te Com p lexes
w ith Silyl, Ger m yl, a n d Sta n n yl Liga n d s
Li Yong,† Edgar Hofer,† Rudolf Wartchow,‡ and Holger Butenscho¨n*,†
Institut fu¨r Organische Chemie, Universita¨t Hannover, Schneiderberg 1B, D-30167 Hannover,
Germany, and Institut fu¨r Anorganische Chemie, Universita¨t Hannover, Callinstrasse 9,
D-30167 Hannover, Germany
Received August 20, 2003
Oxidative addition of hydrosilanes, a hydrogermane, and a hydrostannane to the
((cyclopentadienylalkyl)phosphane)cobalt(I) chelate 1 results in the formation of cyclopen-
tadienylhydridocobalt(III) complexes having a tethered phosphorus ligand and silyl (rac-
4-rac-8), germyl (rac-10), and stannyl substituents (rac-11). The pseudo-four-coordinate
complexes are chiral. The X-ray structures of 5 and 7 have been determined. Variable-
temperature NMR spectra indicate racemization in solution due to reversible dissociation
of the phosphorus ligand. The barrier of this process has been estimated to be in the range
of 13-16 kcal/mol.
Oxidative addition of hydrosilanes at vacant coordi-
nation sites of transition metals is considered a key step
in the transition-metal-catalyzed hydrosilylation of al-
kenes, alkynes, aldehydes, and ketones.1 While hydrosi-
lylation and in particular silylcarbonylation reactions
catalyzed by cobalt(0) carbonyl complexes have been
widely investigated, this is not the case for cyclopenta-
dienylcobalt(I) complexes. Recently Brookhart reported
on 2-fold oxidative addition reactions at pentamethyl-
cyclopentadienylcobalt(I) (Cp*CoI) starting from bis-
(alkene) complexes. This sequence of reactions led to the
formation of remarkable cobalt(V) complexes bearing
two hydrido and two silyl ligands at Cp*Co.2 As the first
step after an alkene decomplexation the authors propose
an oxidative addition leading to a Cp*CoIII silyl hydride
intermediate, which was, however, not isolated.
been connected to cyclopentadienyl ligands, making
chelation possible when a sufficiently long tether is
given. We have focused on phosphanylalkyl-substituted
cyclopentadienylcobalt complexes, and particularly the
di-tert-butylphosphanylethylcyclopentadienylcobalt (Cp#-
Co) chelates, which favorably combine good yields and
crystallization properties. In this context we prepared
rare vinylidene, vinylcarbene, Arduengo type carbene,12
cobaltacyclobutenone,13 and cyclopropene complexes
starting either from the cobalt(II) chloride 2 in the
While some complexes have been stabilized by the
steric and the electronic effects of the pentamethylcy-
clopentadienyl ligand as compared to those of the
unsubstituted cyclopentadienyl ligand, stabilization of
cyclopentadienyl complexes can also be achieved by
chelation when cyclopentadienyl ligands with an at-
tached donor tether are used. In this context nitrogen,3-8
oxygen,3,9 phosphorus,3,8,10,11 and other donors10 have
presence of sodium amalgam or from the ethene cobalt-
(I) chelate 1. Remarkably, the reaction of 2 with tert-
* To whom correspondence should be addressed. E-mail: holger.
butenschoen@mbox.oci.uni-hannover.de.
† Institut fu¨r Organische Chemie, Universita¨t Hannover.
‡ Institut fu¨r Anorganische Chemie, Universita¨t Hannover.
(1) Marciniec, B. In Applied Homogeneous Catalysis with Organo-
metallic Compounds; Cornils, B., Herrmann, W. A., Eds.; VCH:
Weinheim, Germany, 1996; Vol. 1, pp 487-506.
(6) J utzi, P.; Siemeling, U. J . Organomet. Chem. 1995, 500, 175-
185.
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Angew. Chem., Int. Ed. Engl. 1994, 33, 497-526.
(8) Okuda, J . Comments Inorg. Chem. 1994, 16, 185-205.
(9) Siemeling, U. Chem. Rev. 2000, 100, 1495-1526.
(10) Butenscho¨n, H. Chem. Rev. 2000, 100, 1527-1564.
(11) Coville, N. J .; du Plooy, K. E.; Pickl, W. Coord. Chem. Rev. 1992,
116, 1-267.
(12) Foerstner, J .; Kakoschke, A.; Goddard, R.; Rust, J .; Wartchow,
R.; Butenscho¨n, H. J . Organomet. Chem. 2001, 617/ 618, 412-422.
(13) Foerstner, J .; Kakoschke, A.; Wartchow, R.; Butenscho¨n, H.
Organometallics 2000, 19, 2108-2113.
(2) Brookhart, M.; Grant, B. E.; Lenges, C. P.; Prosenc, M. H.; White,
P. S. Angew. Chem. 2000, 112, 1742-1745; Angew. Chem., Int. Ed.
2000, 39, 1676-1679.
(3) Mu¨ller, C.; Vos, D.; J utzi, P. J . Organomet. Chem. 2000, 600,
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(5) J utzi, P.; Redeker, T. Eur. J . Inorg. Chem. 1998, 663-674.
10.1021/om030581b CCC: $25.00 © 2003 American Chemical Society
Publication on Web 11/18/2003

5464 Organometallics, Vol. 22, No. 26, 2003
Yong et al.
butylphosphaethyne in the presence of sodium amalgam
at low temperature resulted in a cleavage of the P-C
triple bond.14
Recently we reported on reactions of 1 with silyl
compounds such as trimethylsilyl chloride, azide, iso-
cyanate, isothiocyanate, and cyanide. While in the first
four cases cobalt(II) chelate complexes with chloro,
azido, isocyanato, and isothiocyanato ligands such as 2
were obtained, trimethylsilyl cyanide gave the dicyano-
cobalt(III) chelate 3.15 These observations suggest reac-
tion sequences involving oxidative additions of the silyl
reagents and possibly the formation of radical interme-
diates. A reaction involving an oxidative addition of a
carbon-silicon bond was also envisaged to explain the
isomerization of the bis(trimethylsilyl)ethyne complex
to the bis(trimethylsilyl)vinylidene complex.12 To better
understand the chemistry of silyl compounds and re-
lated substrates and the Cp#Co system, we investigated
some reactions of 1 with hydrosilanes. In addition, a
hydrogermane and a hydrostannane were included in
this study. We found that hydrosilanes, a hydroger-
mane, and a hydrostannane readily oxidatively add to
the cobalt(I) chelate to give stable cobalt(III) silyl,
germyl, and stannyl hydrides.
F igu r e 1. Structure of one molecule of 5 in the crystal.
The unit cell contains four molecules, in space group
P212121. Selected bond lengths (Å), angles (deg), and
dihedral angle (deg): Co1-H1 ) 1.51(3), Co1-Si1 )
2.236(2), Co1-P1 ) 2.174(2), Co1-C1 ) 2.056(3), Si1-H2
) 1.48(2), Si1-C22 ) 1.909(3), Si1-C16 ) 1.897(3); C(16)-
Si(1)-C(22) ) 104.8(1), C(16)-Si(1)-Co(1) ) 114.4(1),
C(22)-Si(1)-Co(1) ) 117.6(1), P(1)-Co(1)-Si(1) ) 104.60-
(4); H1-Co1-Si1-H2 ) 54(1).
The silylhydridocobalt(III) chelate rac-4 formed quickly
in 85% yield upon treatment of the ethene complex 1
with phenylsilane in toluene at 60 °C. In contrast, the
-16.89) is a doublet of doublets. A H,H COSY spectrum
clearly shows that in addition to the coupling to the
phosphorus atom (2J Co-H,P ) 44.8 Hz) only one coupling
from the cobalt hydride to a silyl hydride exists
(3J Si-H,Co-H ) 3.8 Hz), which was measured from the
signal of Si-H. Obviously the two diastereotopic silyl
hydride substituents show clearly different NMR prop-
erties. When spectra were measured with 31P decoup-
ling, it was possible to observe the missing couplings,
indicating the phosphane ligand being the cause of the
phenomenon. The interesting point is, however, that
only one of the two diastereotopic silyl hydrides in rac-4
is affected.
reaction with triphenylsilane required, presumably as
a result of the steric bulk of the silane, a longer reaction
time. Chelates rac-4-rac-6 were characterized spectro-
scopically. In the IR spectra the Co-H vibrations gave
To get a deeper insight into the conformation of rac-5
with respect to this bond, the compound was crystallized
from toluene at -25 °C in order to perform an X-ray
crystal structure analysis. The unit cell contains four
symmetry-equivalent molecules of equal chirality, one
of which is shown in Figure 1. A crystal containing the
other enantiomer was found as well. The analysis
confirmed the constitution already assigned on the basis
of the spectroscopic data. It was possible to locate either
hydrogen atom, the one bound at cobalt (H1) and that
bound at silicon (H2), in the difference Fourier synthe-
sis, and to refine both as independent atoms. To our
knowledge this is the first time that a cobalt hydride
bond distance (1.51(3) Å) has been determined in a
cyclopentadienylcobalt system. The dihedral angle H1-
Co1-Si1-H2 is 54(1)°, corresponding to a nearly stag-
gered conformation. However, it is difficult to correlate
rise to diagnostic absorption bands around 2060 cm-1 16,17
.
1
Particularly indicative are the H NMR signals around
δ -16 showing coupling to the phosphorus ligand (2J P,H
) 44 Hz), which are assigned to the hydrido ligands.
The 31P NMR chemical shifts between δ 110 and 120
are somewhat higher than in chelates with a phosphane
ligand coordinated at Co(I).15
1
A detailed inspection of the H NMR spectra of rac-
4-rac-6 shows an interesting phenomenon. For rac-6
the signal assigned to the cobalt hydride proton (δ
-16.53), a doublet (2J P,H ) 47.6 Hz), is observed as a
consequence of the coupling to the phosphorus ligand.
The cobalt hydride signal of rac-5 (δ -17.02) also is a
doublet (2J P,H ) 46.5 Hz); in the normal spectrum as
well as in an H,H COSY spectrum, no coupling to the
silyl hydride proton is observed. In contrast to the other
two complexes the cobalt hydride signal of rac-4 (δ
3
this value with that observed for the J Si-H,Co-H NMR
coupling observed for rac-4, as it is not clear to which
of the silyl hydrides the coupling corresponds. In addi-
tion, the conformation observed for solid rac-5 is not
necessarily that of rac-4 in solution.
While the starting material and the silanes used are
achiral, the oxidative addition products rac-4-rac-6
show cobalt-centered chirality. As no chiral information
was given, they are of course formed as racemates.
However, use of either chiral or prochiral hydrosilanes
(14) Foerstner, J .; Olbrich, F.; Butenscho¨n, H. Angew. Chem. 1996,
108, 1323-1325; Angew. Chem., Int. Ed. Engl. 1996, 35, 1234-1237.
(15) Kakoschke, A.; Yong, L.; Wartchow, R.; Butenscho¨n, H. J .
Organomet. Chem. 2003, 674, 86-95.
(16) Rao, C. N. R. Chemical Applications of Infrared Spectroscopy;
Academic Press: New York, 1963.
(17) Dolphin, D.; Wick, A. Tabulation of Infrared Spectral Data;
Wiley: New York, 1977.

Cyclopentadienylhydridocobalt(III) Complexes
Organometallics, Vol. 22, No. 26, 2003 5465
Clearly, the diastereotopicity of the tert-butyl groups is
lost with respect to the NMR time scale at elevated
temperature. The free enthalpies of activation for this
process are estimated to be 16.3, 15.4, and 14.9 kcal/
mol, respectively.18 The process was verified by numer-
ous measurements using a variety of NMR techniques
such as H,H COSY, HSQC, HMBC, P,H correlated
1
spectroscopy, 31P{1H}, and H{31P} NMR. Remarkably
the diastereomeric ratio of rac-7 to rac-8, which was
observed at 295 K, was the same before and after the
coalescence, suggesting that it reflects the thermody-
namically favored composition of the diastereomeric
mixture.
An interpretation of the observed process involves a
temporary decomplexation of the phosphane sidearm,
thereby generating a vacant coordination site in rac-9.
F igu r e 2. Structure of rac-7 in the crystal. Selected bond
lengths (Å) and angles (deg): Co1-C1 ) 2.015(8), Co-C2
) 2.086(10), Co1-C3 ) 2.060(11), Co1-C4 ) 2.014(10),
Co1-C5 ) 2.055(9), Co1-Si1 ) 2.246(3), Co1-P1 )
2.171(3); P1-Co1-Si1 ) 105.4(1).
should cause additional silicon-centered chirality, thus
resulting in the formation of diastereoisomers. To check
the possible diastereoselectivity of such a process, 1 was
treated with methylphenylsilane. The reaction with the
prochiral methylphenylsilane gave the oxidative-addi-
tion products rac-7 (RS/SR) and rac-8 (SS/RR) as a
diastereomeric mixture. The 1H NMR signals of the
This might facilitate a racemization by allowing the
hydride (more likely) or the silyl ligand to change its
place followed by recomplexation of the phosphane
sidearm. As 31P NMR measurements at temperatures
below as well as above the coalescence temperature did
not indicate a decoordinated sidearm,10 this process has
to be rapid relative to the NMR time scale. The ability
to decoordinate and subsequently to recoordinate facili-
tates this unique process and clearly distinguishes the
chelates discussed here from the respective non-chelate
cyclopentadienylcobalt complexes. Alternatively, one
might envisage a sequence of reductive elimination of
hydrosilane followed by oxidative readdition. However,
as treatment of rac-4 with triphenylsilane at tempera-
tures up to 340 K did not result in any formation of rac-
6, we consider this possibility less likely.
hydrido ligands were sufficiently separated to allow the
determination of the diastereomeric ratio to be 16:10
(de 23%). The P-H,Si-H coupling between the two
1
hydride protons is observed only in the P-decoupled H
NMR spectrum; Si-H,Co-H coupling is not observed.
Crystallization of rac-7/rac-8 from hexane/toluene (10:
1) gave crystals suitable for an X-ray crystal structure
analysis. Figure 2 displays the structure of rac-7. In
contrast to the analysis of rac-5 the hydrogen atom
connected to the cobalt atom could not be detected and
therefore had to be calculated.
Having shown the possibility of silane oxidative
additions at Cp#Co, we became interested in the ques-
tion if a hydrogermane behaved similarly. Treatment
of 1 with diphenylgermane in toluene at 60 °C indeed
resulted in the desired oxidative addition, giving rac-
10 in 70% yield. rac-10 appears to be more stable (heat,
When the hydridocobalt chelates rac-4, rac-5, and rac-
7/rac-8 were more deeply investigated by NMR, an
interesting dynamic behavior was observed. As all of
them are chiral, the tert-butyl groups at the phosphorus
1
atoms are diastereotopic and give rise to two H NMR
and two 13C NMR signals for the tert-butyl methyl
groups ([D8]toluene). This is indeed the case at 300 K
for rac-4, at 295 K for rac-5, and at 240 K for rac-7/rac-
8. However, with rising temperature a coalescence is
observed, finally resulting in one signal for these methyl
air) than the silicon derivatives. To our knowledge rac-
10 is the first cyclopentadienylcobalt complex with a
cobalt-germanium bond. Like its homologue rac-5, in
the 1H NMR spectrum a doublet is observed for the
1
groups in the H as well as in the 13C NMR spectrum.
In a similar way the differentiation of the cyclopenta-
dienyl protons is lost at elevated temperature. Control
measurements below the coalescence temperature after
heating gave the same spectra as before. These observa-
tions were made with all three compounds investigated.
(18) Gu¨nther, H. NMR-Spektroskopie; 2nd ed.; Georg Thieme Ver-
lag: Stuttgart, Germany, 1983.

5466 Organometallics, Vol. 22, No. 26, 2003
Yong et al.
3
43.6 Hz, Co-H), 1.06 (d, 9H, J P,H ) 12.6 Hz, C(CH3)3), 1.14
cobalt hydride (δ -16.11), the coupling to the phospho-
rus atom being somewhat larger (2J P,H ) 56.7 Hz). As
with rac-5 no coupling to the silyl hydride is observed.
Next an oxidative addition of a stannane was tried. 1
was treated with tributylstannane in toluene at 60 °C.
The reaction indeed resulted in the formation of the
stannyl cobalt chelate rac-11 in 77% yield. The hydride
3
(d, 9H, J P,H ) 12.6 Hz, C(CH3)3), 1.75-1.88 (m, 2H, CH2),
1.96-2.12 (m, 2H, CH2), 3.49 (s, 1H, HCp), 4.31 (s, 1H, HCp),
4.66 (s, 1H, HCp), 5.06 (s, 1H, HCp), 5.10 (ddd, 1H, 2J Si-H,Si-H
)
6.8 Hz, 3J Si-H,Co-H ) 3.8 Hz, 3J Si-H,P ) 3.8 Hz, 1J Si,H ) 86.6 Hz
3
2
, Si-H), 5.50 (dd, 1H, J Si-H,Co-H ) 12.6 Hz, J Si-H,Si-H ) 6.8
1
Hz, J Si,H ) 79.2 Hz, Si-H), 7.18-7.23 (m, 1H, HPh), 7.24-
7.27 (m, 2H, HPh), 7.28-7.31 (m, 2H, HPh). 13C NMR (50.3 MHz,
C6D6): δ 25.1 (+, d, 2J C,P ) 4.7 Hz, C-6), 29.1 (-, d, 2J C,P ) 3.2
2
Hz, C(CH3)3), 29.8 (-, d, J C,P ) 4.1 Hz, C(CH3)3), 35.6 (+, d,
J C,P ) 15.1 Hz, C(CH3)3), 36.3 (+, d, J C,P ) 15.3 Hz, C(CH3)3),
4
40.6(+, d, J C,P ) 18.5, C-7), 73.9 (-, d, J C,P ) 4.3 Hz, C-2 or
4
C-5), 78.6 (-, C-4 or C-3), 85.2 (-, d, J C,P ) 2.8 Hz, C-5 or
3
C-2), 85.6 (-, C-4 or C-3), 116.4 (+, d, J C,P ) 8.2 Hz, C-1),
127.4 (-, CPh), 127.6 (-, CPh), 135.2 (-, CPh), 145.6 (+, ipso-
C
Ph). 31P NMR (121.5 MHz, C6D6): δ )118.9. MS (70 eV): m/z
(%) 404 (19) [M+], 296 (100) [M+ - SiPhH2 - H], 237 (36) [M+
- SiPhH2 - H - Co], 184 [M+ - SiPh2H - H - 2 C4H8], 137
(32), 107 (96). Anal. Calcd for C21H34CoPSi (404.5): C, 62.36;
H, 8.74. Found: C, 62.39; H, 8.28. HRMS: C21H34CoPSi calcd
m/z 404.1501, found 404.1499.
proton gives rise to a doublet signal at δ -17.17 (2J P,H
) 54.5 Hz). The signal shows 119Sn satelites (2J Sn,H
149.4 Hz).
)
In conclusion, we have shown that hydrosilanes,
-germanes, and -stannanes are able to undergo oxidative
additions with 1, resulting in the formation of the
respective cobalt(III) silyl hydrides. At elevated tem-
peratures an equilibration of the configurations at the
asymmetric cobalt atom takes place, as shown by NMR.
We are currently investigating the chemistry of these
complexes with particular emphasis on catalytic reac-
tions such as hydrosilylation and hydrostannylation.
r a c-[((Di-ter t-bu tylph osph an yl)eth yl)cyclopen tadien yl-
P ]h yd r id o(d ip h en ylsilyl)coba lt(III) (r a c-5): GP, 270 mg
(0.27 mL, 1.5 mmol) of diphenylsilane; 186 mg (0.4 mmol, 79%)
of rac-5, orange crystals (mp 142 °C dec). IR (film, cm-1): ν˜
3061 cm-1 (w), 2963 (w), 2897 (m), 2862 (w), 2060 (w, Co-H),
2001 (w, Si-H), 1472 (m), 1423 (m), 1178 (w), 1094 (m), 918
1
(m), 807 (s, Si-H), 730 (s), 698 (s), 580 (m, Co-H). H NMR
2
(500 MHz, C6D5CD3): δ -17.02 (d, 1H, J P,H ) 46.5 Hz, Co-
3
3
H), 0.90 (d, 9H, J P,H ) 12.5, C(CH3)3), 1.16 (d, 9H, J P,H
)
12.2 Hz, C(CH3)3), 1.70-1.85 (m, 2H, CH2), 1.96-2.06 (m, 2H,
Exp er im en ta l Section
CH2), 3.67 (s, 1H, HCp), 4.49 (s, 1H, HCp), 4.90 (s, 1H, HCp),
3
3
5.04 (s, 1H, HCp), 5.73 (dd, 1H, J Si-H,P ) 5.0 Hz, J Si-H,Co-H
)
Gen er a l Con sid er a tion s. All operations involving air-
sensitive materials were performed under argon using stan-
dard Schlenk techniques. Diethyl ether, THF, benzene, and
toluene were dried over and distilled from Na/K-benzophen-
one. Silica gel was heated at reduced pressure and then put
under normal pressure with argon. This was repeated five
times. Starting materials were either purchased or prepared
according to literature procedures. IR: Bruker ISS 25, Perkin-
Elmer FT 580, FT 1710. 1H NMR: Bruker AVS 200 (200.1
MHz), AVS 400 (400.1 MHz), AVB 500 (500.1 MHz). Chemical
shifts refer to δTMS or to residual solvent peaks. Coupling
constants indicated as J were obtained only in the P-decoupled
spectrum; 29Si,H coupling constants were determined from the
29Si satellites in the 1H NMR spectrum. 13C NMR: Bruker AVS
200 (50.3 MHz), AVS 400 (100.6 MHz). Spectra were obtained
with the DEPT and with the APT techniques. + and - indicate
positive (C, CH2) and negative phase (CH, CH3), respectively.
Chemical shifts refer to δTMS or to residual solvent peaks. 31P
NMR: H decoupled, Bruker AVS 400 (161.9 MHz), 85%
aqueous H3PO4 as external standard. MS, FAB-MS, HRMS:
Finnigan AM 400, Fisons VG Autospec. Elemental analyses:
Haeraeus CHN-Rapid. Melting points: Bu¨chi apparatus ac-
cording to the method of Dr. Tottoli, uncorrected.
1.6 Hz, 1J Si,H ) 89.3 Hz, Si-H), 7.06-7.37 (m, 6H, HPh), 7.82-
7.84 (m, 2H, HPh), 8.05-8.06 (m, 2H, HPh). 13C NMR (50.3 MHz,
C6D6): δ 25.0 (+, d, 2J C,P ) 4.7 Hz, C-6), 29.5 (-, br, C(CH3)3),
29.8 (-, br, C(CH3)3), 36.0 (+, br, C(CH3)3), 40.4 (+, br,
C(CH3)3), 40.6 (+, br, C-7), 75.2 (-, C-2 or C-5), 78.7 (-, C-4
or C-3), 82.6 (-, C-5 or C-2), 85.2 (-, C-4 or C-3), 116.7 (+, d,
3J C,P ) 8.2 Hz, C-1), 127.4 (-, CPh), 128.5 (-, CPh), 135.4 (-,
C
Ph), 136.3 (-, CPh), 146.1 (+, ipso-CPh), 147.7 (+, ipso-CPh).
31P NMR (121.5 MHz, C6D6): δ 117.2. MS (70 eV), m/z (%)
480 (17) [M+], 423 (17) [M+ - Ph], 296 (98) [M+ - SiPh2H -
H], 184 [M+ - SiPh2H - H - 2 C4H8], 137 (32), 106 (96). Anal.
Calcd for C27H38CoPSi (480.7): C, 67.47; H, 7.98. Found: C,
67.05; H, 7.87. HRMS: C27H38CoPSi calcd m/z 480.1816, found
480.1812.
Cr ysta l Str u ctu r e An a lysis of On e En a n tiom er of 5:19
C
27H38CoPSi, molecular weight 480.56, crystal system orthor-
hombic, space group P212121, a ) 10.00(1) Å, b ) 14.52(1) Å,
c ) 17.28(2) Å, R ) 90°, â ) 90°, γ ) 90°, V ) 2509(4) Å3, Z )
4, dcalcd ) 1.272 g cm-3, F(000) ) 1024 e, µ ) 0.81 mm-1, crystal
color red, crystal size 0.15 × 0.15 × 0.17 mm, Stoe IPDS (area
detector) diffractometer, T ) 300 K, λ(Mo KR) ) 0.710 73 Å,
θmin ) 2.35°, θmax ) 26.06°, no absorption correction, no
extinction correction, refinement program SHELXL-93, refine-
ment by least-squares methods (F2), R(F) ) 0.0334, Rw(F2) )
0.0597, 279 parameters, minimum/maximum residual electron
density -0.35/0.26 e Å-3, Flack parameter x ) 0.02(1).
r a c-[((Di-ter t-bu tylph osph an yl)eth yl)cyclopen tadien yl-
P ]h yd r id o(tr ip h en ylsilyl)coba lt(III) (r a c-6): GP, 382 mg
(1.5 mmol) of triphenylsilane; 147 mg (0.3 mmol, 54%) of rac-
6, deep red crystals (mp 138 °C dec). IR (film, cm-1): ν˜ 3066
cm-1 (w), 2959 (s), 2924 (s), 2867 (s), 2341 (s, Co-H), 1465 (s),
Gen er a l P r oced u r e (GP ) for Oxid a tive Ad d ition of
Hyd r osila n e, -ger m a n e, a n d -sta n n a n e a t Cp #Co. In a 20
mL Schlenk flask 158 mg (0.49 mmol) of 1 and 1.47 mmol of
the hydrosilane, -germane, or -stannane in 5 mL of toluene
was stirred at 60 °C for 10 h. After the mixture was cooled to
25 °C, the excess hydride and the solvent were removed into
a old trap at reduced pressure. The solid product was recrys-
tallized from toluene at -20 °C.
r a c-[((Di-ter t-bu tylph osph an yl)eth yl)cyclopen tadien yl-
P ]h yd r id o(p h en ylsilyl)coba lt(III) (r a c-4): GP, 158 mg
(0.30 mL, 1.5 mmol) of phenylsilane; 168 mg (0.4 mmol, 85%)
of rac-4, yellow crystals (mp 122-123 °C). IR (film, cm-1): ν˜
3062 (w), 2960 (w), 2897 (m), 2864 (w), 2049 (s, Co-H), 1941
(w, Si-H), 1475 (m), 1427 (m), 1183 (w), 1102 (m), 948 (m),
833 (s, Si-H), 822 (s, Si-H), 729 (m), 701 (m), 581 (m, Co-
(19) The crystallographic data (without structure factors) of the
structures described in this publication were deposited as Supplemen-
tary Publication Nos. CCDC 215326 (5), 215327 (ent-5), and 215328
(rac-7) at the Cambridge Crystallography Data Centre. Copies of the
data can be obtained at no charge from the following address: The
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K. (telefax,
Int. + 1223/336-033; e-mail, deposit@ccdc.cam.ac.uk).
1
2
H). H NMR (500 MHz, C6D5CD3): δ -16.89 (dd, 1H, J P,H
)

Cyclopentadienylhydridocobalt(III) Complexes
Organometallics, Vol. 22, No. 26, 2003 5467
1428 (s), 1119 (m), 1096 (m), 998 (s), 803 (s), 771 (s), 514 (s,
Co-H). H NMR (400 MHz, C6D6): δ -16.53 (d, 1H, Co-H, J
H), 1472 (s), 1425 (s), 1260 (m), 1078 (m), 935 (s), 813 (s), 718
1
(s), 584 (s, Co-H). 1H NMR (400 MHz, 300 K, C6D6): δ -16.11
2
3
) 47.6 Hz), 0.78-0.80 (s, 9H, C(CH3)3), 0.83-0.86 (s, 9H,
C(CH3)3), 1.64-1.73 (m, 2H, CH2), 1.92-1.98 (m, 2H, CH2),
3.41 (s, 1H, HCp), 4.31 (s, 1H, HCp), 4.97 (s, 1H, HCp), 5.01 (s,
1H, HCp), 7.18-7.20 (m, 3H, HPh), 7.24-7.28 (m, 6H, HPh),
8.08-8.10 (m, 6H, HPh). 13C NMR (50.3 MHz, C6D6): δ 24.4
(+, d, 2J C,P ) 5.2 Hz, C-6), 29.7 (-, d, 2J C,P ) 3.7 Hz, C(CH3)3),
29.8 (-, d, 2J C,P ) 4.1 Hz, C(CH3)3), 34.9 (+, d, J C,P ) 14.0 Hz,
C(CH3)3), 41.6 (+, br, C(CH3)3), 41.8 (+, br, C-7), 76.9 (-, br,
C-2 or C-5), 80.1 (-, C-4 or C-3), 84.1 (-, br, C-5 or C-2), 85.4
(d, 1H, Co-H, J P,H ) 56.7 Hz), 0.97 (d, J P,H ) 12.7 Hz, 9H,
C(CH3)3), 1.14 (d, 3J P,H ) 12.5 Hz, 9H, C(CH3)3), 1.71-1.82 (m,
2H, CH2), 1.99-2.06 (m, 2H, CH2), 3.78 (s, 1H, HCp), 4.56 (s,
1H, HCp), 4.94 (s, 1H, HCp), 4.98 (s, 1H, HCp), 5.35-5.39 (m,
1H, Si-H), 7.25 (s, 2H, HPh), 7.48-7.54 (m, 3H, HPh), 7.62-
7.92 (m, 2H, HPh), 8.01 (m, 3H, HPh). 13C NMR (50.3 MHz,
C6D6): δ 24.9 (+, d, 2J C,P ) 4.7 Hz, C-6), 29.2 (-, d, 2J C,P ) 3.2
2
Hz, C(CH3)3), 29.9 (-, d, J C,P ) 3.9 Hz, C(CH3)3), 35.8 (+, d,
J C,P ) 16.3 Hz, C(CH3)3), 36.0 (+, d, J C,P ) 12.3 Hz, C(CH3)3),
3
2
4
(-, C-4 or C-3), 118.2 (+, d, J C,P ) 7.6 Hz, C-1), 127.0 (-,
40.2 (+, d, J C,P ) 19.2, C-7), 73.0 (-, d, J C,P ) 4.7 Hz, C-2 or
C
Ph), 127.3 (-, CPh), 137.4 (-, CPh), 146.6 (+, ipso-CPh)). 31P
C-5), 79.4 (-, C-4 or C-3), 84.4 (-, C-4 or C-3), 84.8 (-, d, 4J C,P
) 2.5 Hz, C-5 or C-2), 115.1 (+, d, J C,P ) 8.1 Hz, C-1), 128.7
3
NMR (121.5 MHz, C6D6): δ 110.2. MS (70 eV): m/z (%) 557
(2) [M+ + 1], 556 (4) [M+], 555 (7) [M+ - 1], 533 (90) [M+
-
-
(-, CPh), 129.3 (-, CPh), 135.5 (-, CPh), 148.5 (+, ipso-CPh), 149.8
(+, ipso-CPh). 31P NMR (121.5 MHz, C6D6): δ 117.7. MS (70
eV): m/z (%) 527 (8), 526 (11) [M+], 525 [M+ - 1], 479 (11),
423 (13), 375 (12), 331 (11), 296 (100) [M+ - GePh2H - H],
183 (35) [M+ - GePh2H - 2 C4H8], 121 (46), 91 (42), 71 (22).
Anal. Calcd for C27H38CoGeP (526.12): C, 61.64; H, 7.28.
2Me], 296 (3) [M+ - SiPh2H - H], 260 (79), 182 (100) [M+
SiPh2H - H - 2 C4H8], 183 (65), 137 (32), 105 (42). HRMS:
C
27H38PCoSi m/z calcd 556.2274, found 556.2471.
r a c-[(Di-ter t-bu tylp h osp h a n yl)eth ylcyclop en ta d ien yl-
P ](h yd r id o)(m et h ylp h en ylsilyl)cob a lt (III) (r a c-7/r a c-
8): GP, 179 mg (0.20 mL, 1.5 mmol) of methylphenylsilane;
117 mg (0.3 mmol, 57%) of rac-7/rac-8 (mixture of diastereo-
mers, 8:5, NMR), orange crystals. IR (film, cm-1): ν˜ 3067 cm-1
(w), 3028 (w), 3005 (w), 2963 (s), 2898 (s), 2862 (s), 2052 (s,
Co-H), 1931 (s, Si-H), 1463 (s), 1425 (s), 1172 (m), 1020 (m),
Found: C, 61.38; H, 7.02. HRMS:
526.1229, found 526.1255.
C27H38CoGeP m/z calcd
r a c-[((Di-ter t-bu tylph osph an yl)eth yl)cyclopen tadien yl-
P ]h yd r id o(tr ibu tylsta n n yl)coba lt(III) (r a c-11): GP, 156
mg (0.54 mmol) of tributylstannane; 226 mg (0.39 mmol, 77%)
of rac-11, orange crystals (mp 126 °C, dec). IR (film, cm-1): ν˜
3036 cm-1 (w), 2955 (s), 2920 (s), 2871 (s), 2852 (s), 2440 (m,
Co-H), 1807 (s), 1531 (s), 1643 (s), 1417 (m), 1375 (m),
1291(m), 1260 (m), 1145 (m), 1072 (m), 1019 (m), 960 (s, Sn-
932 (s), 816 (s, Si-H), 730 (s), 585 (s, Co-H). 1H NMR (400
2
MHz, 295 K, C6D6): rac-7, δ -17.12 (d, 1H, Co-H, J P,H
)
46.7 Hz), 0.68 (s, br, 3H, CH3), 1.13-1.32 (m, 18H, C(CH3)3),
1.85-1.93 (m, 2H, CH2), 2.01-2.21 (m, 2H, CH2), 3.59, 3.90,
4.45, 4.69, 4.93, 5.07, 5.17 (7 s, in total 4H, HCp), 5.35-5.43
1
C), 815 (s, Sn-C), 674 (s), 517 (s, Co-H). H NMR (400 MHz,
3
3
1
(m, br, 1H, J Si-H,C-H ) 3.7 Hz, J Si-H, Co-H ) ca. 3.7 Hz, J Si,H
) 82.7 Hz, 2J Si,C-H ) 6.4 Hz, 3J Si-H,P not resolved, Si-H), 7.29-
7.32 (m, 1H, HPh), 7.36-7.38 (m, 2H, HPh), 7.43-7.48 (m, 2H,
HPh); rac-8, δ -17.28 (d, 2J P,H ) 47.3 Hz), other signals covered
by those of rac-7. 13C NMR (50.3 MHz, C6D6, only one set of
300 K, C6D6): δ -17.17 (d, 1H, Co-H, 2J P, H ) 54.6 Hz), 0.65-
0.73 (m, 9H, CH3), 0.78-0.80 (m, 9H, C(CH3)3), 0.83-0.86 (m,
9H, C(CH3)3), 0.89-0.93 (m, 6H, CH2), 1.03-1.07 (m, 6H, CH2),
1.53-1.61 (m, 6H, CH2), 2.66-2.84 (m, 4H, CH2), 3.88 (s, 1H,
H
Cp), 4.43 (s, 1H, HCp), 4.99 (s, 1H, HCp), 5.01 (s, 1H, HCp). 13C
2
signals is observed): δ 15.3 (+, SiCH3), 26.0 (+, d, J C,P ) 4.8
NMR (100.6 MHz, C6D6): δ 10.3 (+, CH2), 13.9 (-, CH3), 16.6
2
2
Hz, C-6), 30.3 (-, br, C(CH3)3), 30.9 [-, br, C(CH3)3], 35.7 (+,
br, C(CH3)3), 36.5 (+, br, C(CH3)3), 41.63 (+, d, J C,P ) 18.6,
C-7), 75.7 (-, br, C-2 or C-5), 79.4 (-, C-4 or C-3), 84.9 (-, br,
C-5 or C-2), 85.9 (-, C-4 or C-3), 117.1 (+, br, C-1), 128.5 (-,
(+, CH2), 26.5 (+, d, J C,P ) 5.9 Hz, C-6), 27.1 (-, d, J C,P )
4.4 Hz, C-9, C-10, C-11), 28.2 (+, CH2), 29.2 (+, CH2), 31.5 (-,
2
d, J C,P ) 4.8 Hz, C-13, C-14, C-15), 31.7 (+, C-7), 36.1 (+, d,
J C,P ) 14.0 Hz, C-8), 36.7 (+, C-12), 78.1 (-, C-2 or C-5), 79.2
(-, C-4 or C-3), 82.9 (-, C-5 or C-2), 84.5 (-, C-4 or C-3), 116.1
C
Ph), 129.3 (-, CPh), 135.4 (-, CPh), 146.7 (+, ipso-CPh). 31P NMR
3
(121.5 MHz, C6D6): δ 117.9, 118.1. MS (70 eV): m/z (%) 418
(41) [M+], 296 (100) [M+ - SiPhMeH - H], 184 (77) [M+
SiPhMeH - H - 2(C4H8)], 121 (80), 79 (25). Anal. Calcd for
22H36PCoSi (418.2): C, 63.16; H, 8.61. Found: C, 63.01; H,
8.60.
Cr ysta l Str u ctu r e An a lysis of r a c-7:19 C22H36CoPSi,
(+, d, J C,P ) 7.6 Hz, C-1). 31P NMR (121.5 MHz, C6D6): δ
-
122.2. MS (70 eV; C27H54PCoSn (587)): m/z (%) 587 (6) [M+],
586 (3) [M+ - 1], 546 (56) [M+ - C3H7 + 1], 545 (17) [M+
-
C
C3H7], 544 (77) [M+ - C3H7 - 1], 540 (100) [M+ - 3CH3 - 2],
539 (81) [M+ - 3CH3 - 3], 530 (23) [M+ - C4H9 - 1], 484 (78)
[M+ - C4H9 - 3CH3 - 1], 415 (20) [M+ - 3 C4H9 -1], 317 (11)
[M+ - 3 C4H9 - CH2CH2 - 3CH3 - 1], 296 (5) [M+ - Sn(C4H9)3],
254 (46), 251 (78), 182 (79) [M+ - Sn(C4H9)3 - H - 2 C4H8],
183 (61), 137 (32), 105 (44). HRMS: C27H54PCoSn m/z calcd
588.2317, found 588.2310.
molecular weight 418.50, crystal system monoclinic, space
group P21/c, a ) 13.569(4) Å, b ) 10.350(3) Å, c ) 15.735(4)
Å, R ) 90°, â ) 98.30(3)°, γ ) 90°, V ) 2186.7(11) Å3, Z ) 4,
dcalcd ) 1.271 g cm-3, F(000) ) 896 e, µ ) 0.916 mm-1, crystal
color orange-red, crystal size 0.26 × 0.18 × 0.15 mm, Stoe
IPDS (area detector) diffractometer, T ) 300 K, λ(Mo KR) )
0.710 73 Å, 17804 measured, 3467 unique, and 793 observed
(I > 2σI) reflections (Rint ) 0.109), θmin ) 2.36°, θmax ) 24.27°,
no absorption correction, no extinction correction, refinement
program SHELXL-93, refinement by least-squares methods
(F2), R(F) ) 0.0667, Rw(F2) ) 0.1313, 119 parameters, minimum/
Ack n ow led gm en t. We thank Ms. K. Kirleis for
experimental assistance. This work was kindly sup-
ported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie as well as by the
joint research initiative “Biologisch aktive Naturstoffe:
Synthetische Diversita¨t”. We acknowledge donations of
chemicals and solvents by Phenolchemie and Wacker.
maximum residual electron density -0.34/0.40 e Å-3
.
r a c-[((Di-ter t-bu tylph osph an yl)eth yl)cyclopen tadien yl-
P ]h yd r id o(d ip h en ylger m yl)coba lt(III) (r a c-10): GP, 335
mg (0.36 mL, 1.5 mmol) of diphenylgallane; 180 mg (0.3 mmol,
70%) of rac-10, orange crystals, mp 164 °C dec. IR (film, cm-1):
ν˜ 3060 cm-1 (w), 3028 cm-1 (w), 3005 cm-1 (w), 2989 cm-1
(w), 2962 (s), 2897 (s), 2861 (s), 2052 (s, Co-H), 1949 (s, Ge-
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray
crystallographic data for 5, ent-5, and rac-7. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM030581B