Synthesis and characterization of η5-tetramethylcyclopentadienyl- hydrido- and -chloro-silyl-η1-amido zirconium complexes

Article abstract of DOI:10.1016/S0022-328X(03)00122-0

The silylated tetramethylcyclopentadienes C₅Me₄ (SiMeCl₂)(SiMe₃) (1) and C₅ Me₄H(SiMeHCl) (3) were isolated by reaction of their corresponding trimethylsilyltetramethylcyclopentadienyl and tetramethylcyclopentadienyl lithium salts with SiMeCl₃ and SiMeHCl₂, respectively. Reaction of a toluene suspension of ZrCl₄ with one equivalent of 1 afforded the monocyclopentadienyl zirconium complex [Zr(η⁵- C₅Me₄SiMeCl₂)Cl₃] (2). Reaction of 3 with NH₂^tBu gave C₅Me₄H[SiMeH(NH^tBu)] (4) which was further metallated to give Li₂[C₅ Me₄SiMeH(N^tBu)] (5), used to prepare the silyl-η¹-amido zirconium derivative [Zr(η⁵-C₅Me₄ SiMeH-η¹-N^tBu)Cl₂] (6) by reaction with ZrCl₄(THF)₂. Chlorination of 6 with BCl₃ afforded [Zr(η⁵-C₅ Me₄SiMeCl-η¹-N^tBu)Cl₂] (12). Alkylation and amidation of 6 and 12 provided the corresponding disubstituted [Zr(η⁵-C₅Me₄ SiMeH-η¹-N^tBu)R₂] (R=Me 7, CH₂Ph 8, NMe₂ (9) and [Zr(η⁵-C₅Me₄ SiMeCl-η¹-N^tBu)Me₂] (13) and monosubstituted [Zr(η⁵-C₅Me₄ SiMeH-η¹-N^tBu)ClR] (R=C₆F₅ 10, N(SiMe₃)₂ (11) and [Zr(η⁵-C₅Me₄ SiMeCl-η¹-N^tBu)Cl{N(SiMe₃) ₂}] (14). All of the new compounds reported were characterized by elemental analyses and NMR spectroscopy.

Full text of DOI:10.1016/S0022-328X(03)00122-0

Journal of Organometallic Chemistry 671 (2003) 172ꢁ178
/
www.elsevier.com/locate/jorganchem
Synthesis and characterization of h5-tetramethylcyclopentadienyl-
hydrido- and -chloro-silyl-h1-amido zirconium complexes
Ana Bele´n Va´zquez, Pascual Royo *
Departamento de Qu´ımica Inorga´nica, Facultad de Ciencias, Universidad de Alcala´, Campus Universitario, Edificio de Farmacia, E-28871 Alcala´ de
Henares, Spain
Received 9 December 2002; received in revised form 10 February 2003; accepted 10 February 2003
Abstract
The silylated tetramethylcyclopentadienes C5Me4(SiMeCl2)(SiMe3) (1) and C5Me4H(SiMeHCl) (3) were isolated by reaction of
their corresponding trimethylsilyltetramethylcyclopentadienyl and tetramethylcyclopentadienyl lithium salts with SiMeCl3 and
SiMeHCl2, respectively. Reaction of a toluene suspension of ZrCl4 with one equivalent of 1 afforded the monocyclopentadienyl
zirconium complex [Zr(h5-C5Me4SiMeCl2)Cl3] (2). Reaction of 3 with NHt2Bu gave C5Me4H[SiMeH(NHtBu)] (4) which was further
metallated to give Li2[C5Me4SiMeH(NtBu)] (5), used to prepare the silyl-h1-amido zirconium derivative [Zr(h5-C5Me4SiMeH-h1-
NtBu)Cl2] (6) by reaction with ZrCl4(THF)2. Chlorination of 6 with BCl3 afforded [Zr(h5-C5Me4SiMeCl-h1-Nt Bu)Cl2] (12).
Alkylation and amidation of 6 and 12 provided the corresponding disubstituted [Zr(h5-C5Me4SiMeH-h1-NtBu)R2] (Rꢀ
/
Me 7,
CH2Ph 8, NMe2 9) and [Zr(h5-C5Me4SiMeCl-h1-NtBu)Me2] (13) and monosubstituted [Zr(h5-C5Me4SiMeH-h1-NtBu)ClR] (Rꢀ
/
C6F5 10, N(SiMe3)2 11) and [Zr(h5-C5Me4SiMeCl-h1-NtBu)Cl{N(SiMe3)2}] (14). All of the new compounds reported were
characterized by elemental analyses and NMR spectroscopy.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Zirconium; Linked amido-cyclopentadienyl ligand; Synthesis
1. Introduction
chlorides MCl2Bu2 [5], with the elimination of amine,
toluene and butane, respectively, is not a convenient
method as further transformation into the correspond-
ing metal chlorides is required. Metathetical reactions of
metal halides with the doubly lithiated precursor [6] are
not available as the formation of Li2[C5R4SiMeCl(NR?)]
is accompanied by rapid elimination of lithium chloride
affording silylene decomposition products. Intramole-
cular aminolysis [7] by reaction of [M(C5R4SiMeCl2)Cl3]
with excess primary amines or with the corresponding
lithium amides has proved to be an efficient synthetic
Bidentate ligands in which the h5-cyclopentadienyl
group is tethered by one additional anionic or neutral
N- or O-donor group form interesting types of metal
chelate complexes, reviewed recently [1]. In particular,
Group
4
metal (h5-cyclopentadienyl)silyl-h1-amido
complexes provide ‘constrained geometry’ catalysts of
increasing interest in the production of high-molecular
weight copolymers as a result of their well known lower
steric requirements and enhanced acidity [2].
We were interested in isolating cyclopentadie-
nyl(chlorosilyl)-h1-amido Group 4 and 5 metal deriva-
tives, by exploring new, more convenient synthetic
strategies. Double deprotonation of C5R4H[SiMeCl-
method when selective reactions at SiÃ
bonds can be made and has been used to isolate various
Group 4 metal [8ꢁ12] and Nb complexes [13]. An
alternative method could be based on the chlorination
/
Cl and MÃ
/
Cl
/
(NHR?)] (Rꢀ
/
H, Me) using basic tetra-amides
M(NR2)4 [3], tetra-benzyls M(CH2Ph)4 [4] and di-butyl-
of SiÃ
/
H bonds [14] in the more easily accessible
[M(C5R4SiMeH-h1-NR?)Cl2] derivatives.
We report here the application of convenient methods
to synthesize the new zirconium complexes [Zr(h5-
C5Me4SiMeCl2)Cl3], [Zr(h5-C5Me4SiMeH-h1-NtBu)-
Cl2] and [Zr(h5-C5Me4SiMeCl-h1-NtBu)Cl2] and some
* Corresponding author. Tel.:
8854683.
E-mail address: pascual.royo@uah.es (P. Royo).
ꢂ
/
34-91-8854765; fax:
ꢂ/34-91-
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00122-0

A.B. Va´zquez, P. Royo / Journal of Organometallic Chemistry 671 (2003) 172ꢁ
/178
173
of their alkyl and amido derivatives which were char-
1
as a white solid in 96% yield which was characterized by
elemental analysis. An equimolar mixture of 5 and
ZrCl4(THF)2 was stirred for 2 days at room temperature
to give the silyl-h1-amido complex [Zr(h5-C5Me4Si-
MeH-h1-NtBu)Cl2] (6) as a yellow solid in 72% yield
(see Scheme 2).
acterized by elemental analysis and H-, 13C- and 29Si-
NMR spectroscopy.
2. Results and discussion
As shown in Scheme 3, alkylation of compound 6
with two equivalents of MgClR (Rꢀ
afforded the dialkyl complexes [Zr(h5-C5Me4SiMeH-
h1-NtBu)R2] (Rꢀ
Me 7, CH2Ph 8) and a similar
reaction with two equivalents of LiNMe2 gave the
diamido complex
[Zr(h5-C5Me4SiMeH-h1-NtBu)-
(NMe2)2] (9). However, only monosubstituted com-
pounds resulted when bulkier substituents were used.
So, the same reaction with MgCl(C6F5) gave only the
monoalkylated derivative [Zr(h5-C5Me4SiMeH-h1-
NtBu)Cl(C6F5)] (10) even when excess alkylating agent
was used. The same behaviour was observed for the
reaction with Li[N(SiMe3)2] which afforded the mono-
amido complex [Zr(h5-C5Me4SiMeH-h1-NtBu)Cl{N-
(SiMe3)2}] (11).
/
Me, CH2Ph)
The disilylated precursor [1-(dichloromethylsilyl)-1-
trimethylsilyl]tetramethyl cyclopentadiene (1) was iso-
lated as a pale yellow solid in 94% yield by reaction of
/
the
corresponding
(trimethylsilyl)cyclopentadienyl
lithium salt with trichloromethylsilane in THF. Com-
pound 1 was characterized by elemental analysis and
NMR spectroscopy (see Section 3). As shown in Scheme
1, a slow reaction of one equivalent of 1 with a toluene
suspension of ZrCl4 took place on heating the mixture
for 3 h at 100 8C affording the monocyclopentadienyl
derivative [Zr(h5-C5Me4SiMeCl2)Cl3] (2), isolated in
67% yield as a pale brown solid. Compound 2 which
could not be obtained free of toluene (ca. 2%, see
Section 3) was characterized by elemental analysis and
1
NMR spectroscopy. The H- and 13C-NMR spectra of
The chloro 6, alkyl 7, 8, 10 and amido 9 and 11
complexes are air sensitive and thermally stable com-
pounds which can be stored for long periods under an
inert atmosphere. All were soluble in hexane and
complex 2 show the behaviour expected for AA?BB? ring
spin systems.
Various reactions were investigated to determine the
isolated as yellow solids (6, 8ꢁ
pure waxy orange product 7 by concentration and
cooling their hexane solutions at ꢃ30 8C. Their for-
/11) or an analytically
comparative reactivity of the SiÃ
/
Cl and ZrÃ/Cl bonds of
compound 2. All the reactions using different molar
ratios of tert-butylamine and its lithium salt resulted in
inseparable mixtures of various substituted products.
/
mulations are consistent with the analytical and NMR
spectroscopic data.
This unselective reactivity of both SiÃ
/
Cl and ZrÃ
/Cl
All of the complexes 6ꢁ9 have two identical zirconium
/
bonds, is an important limitation when the objective is
to isolate (h5-cyclopentadienyl-chlorosilyl)-h1-amido
complexes. For this reason, we decided to use a different
approach based on the known capacity of BCl3 to
bound substituents and are asymmetric molecules with a
1
chiral centre at silicon. Their H-NMR spectra showed
the expected four resonances for the ring methyl groups
of a ABCD spin system, along with one singlet due to
the t-butylamido ligand and one doublet and one
quadruplet corresponding to the Me and H groups
bound to silicon, respectively. Accordingly, the 13C-
NMR spectra showed four resonances for the ring
methyl groups and five resonances for the ring carbon
atoms, along with two resonances for the t-butylamido
chlorinate SiÃ
/
H bonds [14], and because the dilithium
salt of the aminosilyl cyclopentadiene Li2[C5Me4Si-
MeH(NtBu)] can be easily isolated.
Reaction of Li(C5Me4H) with SiMeHCl2 in THF gave
the silylated cyclopentadiene C5Me4H(SiMeHCl) (3),
isolated as a yellow oil in 89% yield and characterized by
elemental analysis and NMR spectroscopy. Reaction of
3 with two equivalents of NHt2Bu in THF afforded the
aminosilylcyclopentadiene derivative C5Me4H[SiMeH-
(NHtBu)] (4) isolated as a yellow oil in 93% yield and
characterized by elemental analysis and NMR spectro-
scopy. Metallation of 4 with two equivalents of LinBu
afforded the dilithium salt Li2[C5Me4SiMeH(NtBu)] (5)
Scheme 1.
Scheme 2.

174
A.B. Va´zquez, P. Royo / Journal of Organometallic Chemistry 671 (2003) 172ꢁ178
/
Scheme 3.
Scheme 4.
ligand and one resonance corresponding to the silicon
bound methyl group. The two non-equivalent methyl
groups in 7 give rise to two resonances (1H and 13C)
whereas the benzyl groups in 8 contain diastereotopic
methylene protons giving rise to four doublets (1H) and
two 13C resonances. Each of the non-equivalent di-
methylamido groups in 9 show equivalent methyl groups
observed as two singlets (1H and 13C) indicating that
amido substituents rotate freely.
and the two highfield signals observed at d ꢃ
0.04 for the two ZrÃMe bonds analogous to those
observed for 7.
/
0.04 and
/
A similar reaction of 12 with LiN(SiMe3)2 afforded
the monoamido complex [Zr(h5-C5Me4SiMeCl-h1-
NtBu)Cl{N(SiMe3)2}] (14), isolated as a pale yellow
solid in 97% yield and characterized by elemental
analysis and NMR spectroscopy. Complex 14 contains
two chiral centres at silicon and zirconium and consists
of a mixture of two enantiomeric pairs of diastereomers
in a 1/1 molar ratio, which could not be separated. As
described above for the related monosubstituted com-
The monosubstituted pentafluorophenyl 10 and ami-
do 11 complexes contain two chiral centres at zirconium
and silicon and comprise 1.8/1 (10) and 1.6/1 (11) molar
ratio mixtures of two enantiomeric pairs of diastereo-
mers which could not be separated. The pairs can be
clearly distinguished by the two identical sets of
1
pounds 10 and 11, the H- and 13C-NMR spectra of 14
show two identical sets of resonances, each one corre-
sponding to one of the two diastereomers (see Section
3).
1
resonances observed in their H- and 13C-NMR spectra
(see Section 3), although some of the resonances appear
as overlapped signals.
The p-bonding contribution of the bridging t-butyla-
/
Conversion of the hydrido- into the chloro-silyl
derivative [Zr(h5-C5Me4SiMeCl-h1-NtBu)Cl2] (12) was
carried out by reaction of a dichloromethane solution of
6 with one equivalent of a 1 M heptane solution of BCl3
(see Scheme 4). Complex 12 was isolated as a pale yellow
solid in 72% yield and was characterized by elemental
analysis and NMR spectroscopy, its 1H and 13C spectral
pattern being similar to those described for 6 (see
Section 3). When complex 12 was treated with two
mido ligand in complexes 6ꢁ
/
14 measured by the Ddꢀ
(dCtertꢃdCMe) values [15] is in the range known for this
/
type of cyclopentadienylsilyl-h1-amido complexes going
from 20.8 ppm for the more donating 7 to 25.8 ppm for
the less donating 10 substituents.
3. Experimental
equivalents of MgClMe selective alkylation of the ZrÃ
/
Cl
bonds took place to give the dimethyl complex [Zr(h5-
C5Me4SiMeCl-h1-NtBu)Me2] (13), isolated as a pale
yellow solid in 65% yield and characterized by elemental
analysis and NMR spectroscopy. Formulation of 13 is
3.1. General considerations
All manipulations were performed under argon using
Schlenk and high-vacuum line techniques or a glovebox
MBraun model 150B-G. Solvents were purified by
distillation under argon before use by employing the
1
consistent with its H- and 13C-NMR spectra which are
similar to those described above for the related dimethyl
complex 7, demonstrating the presence of only one
appropriate drying agent (sodium for toluene, sodiumꢁ
/
chiral centre at silicon. The presence of the unaltered SiÃ
/
potassium alloy for hexane and pentane, phosphorus
pentoxide for CH2Cl2 and sodium-benzophenone for
diethyl ether and THF). Deuterated solvents were stored
Cl bond is also consistent with the downfield signal
observed at d 0.75, analogous to that observed for 12

A.B. Va´zquez, P. Royo / Journal of Organometallic Chemistry 671 (2003) 172ꢁ
/178
175
˚
over activated 4 A molecular sieves and degassed by
several freezeꢁ
thaw cycles. NHt2Bu (Aldrich) was dis-
hot solvent was removed under vacuum to give a pale
brown solid, which was washed with cold hexane and
was characterized as 2 (2.83 g, 6.55 mmol, 67% yield).
Anal. Calc. for C10H15Cl5SiZr(0.1C7H8): C, 29.14; H,
/
˚
tilled before use and stored over activated 4 A molecular
sieves. C5Me4H2 (Aldrich), LinBu (Aldrich), SiMeCl3
(Aldrich), SiMeHCl2 (ABCR), BCl3 (Aldrich), MgClMe
(Aldrich), MgClBz (Aldrich), ZrCl4 (Fluka) were pur-
chased from commercial sources and used without
further purification. Li(C5Me4H) [16], C5Me4H(SiMe3)
[17], ZrCl4(THF)2 [18] and LiN(SiMe3)2 [19] were
prepared according to the literature procedures. C, H
1
3.58. Found: C, 29.16; H, 3.46%. H-NMR (300 MHz,
C6D6, 25 8C): d 0.96 (s, 3H, SiMeCl2), 1.68 (s, 6H,
C5Me4), 2.19 (s, 6H, C5Me4). 1H-NMR (300 MHz,
CDCl3, 25 8C): d 1.22 (s, 3H, SiMeCl2), 2.20 (s, 6H,
C5Me4), 2.47 (s, 6H, C5Me4). 13C{1H}-NMR (75 MHz,
C6D6, 25 8C): d 8.6 (SiMeCl2), 12.3, 15.5 (C5Me4), 119.8
(Cipso, C5Me4), 135.6, 136.9 (C5Me4). 13C{1H}-NMR
(75 MHz, CDCl3, 25 8C): d 9.0 (SiMeCl2), 12.9, 15.8
(C5Me4), 119.8 (Cipso, C5Me4), 135.5, 136.8 (C5Me4).
and N microanalyses were performed on a Perkinꢁ
/
Elmer 240B and/or Heraeus Ã
/
CHNÃ
/
O-rapid microana-
lyzer. NMR spectra, measured at 25 8C, were recorded
on a Varian Unity FT-300 (1H-NMR at 300 MHz, 13C-
NMR at 75 MHz, 29Si-NMR at 59.6 MHz). In the H-
NMR spectra, the chemical shifts refer to the residual
1
3.4. Synthesis of C5Me4H(SiMeHCl) (3)
proton signal of the solvent (dꢀ
and dꢀ
7.15 ppm for C6H6), in 13C-NMR spectra to the
solvent signal (dꢀ77.0 ppm for CHCl3-d1 and dꢀ128.0
ppm for C6H6-d6) and in 29Si-NMR spectra to the
resonance of external Me4Si (dꢀ0.0 ppm).
/
7.24 ppm for CHCl3
Methyldichlorosilane (4.3 ml, 41 mmol) was added at
once to a suspension of Li(C5Me4H) (5.04 g, 39 mmol)
/
/
/
in THF (125 ml) at ꢃ
slowly warmed to r.t. and stirred for 17 h. After THF
removal, the residue was extracted into hexane (2ꢄ75
/
78 8C. The reaction mixture was
/
/
ml). The hexane solvent was removed under vacuum to
give 3 as a yellow oil (6.99 g, 35 mmol, 89% yield). Anal.
Calc. for C10H17ClSi: C, 59.82; H, 8.53. Found: C,
60.23; H, 8.64%. 1H-NMR (300 MHz, CDCl3, 25 8C): d
3.2. Synthesis of (C5Me4)(SiMeCl2)(SiMe3) (1)
A 1.6 M solution of LinBu in hexane (17 ml, 27 mmol)
was added dropwise, at 0 8C, to a solution of
C5Me4H(SiMe3) (5.25 g, 27 mmol) in THF. The reaction
mixture was slowly warmed to room temperature (r.t.)
and stirred for 16 h. After THF removal, the residue was
0.05 (d, 3H, SiMe, Jꢀ3 Hz), 1.81 (2s, 6H, C5Me4), 1.94
/
(s, 3H, C5Me4), 1.99 (s, 3H, C5Me4), 3.21 (br s, 1H,
C5Me4H), 4.80 (m, 1H, SiH). 13C{1H}-NMR (75 MHz,
CDCl3, 25 8C): d ꢃ4.2 (SiMe), 11.2, 11.4, 13.5, 13.9
/
washed with pentane (2ꢄ50 ml) to give Li[C5-
/
(C5Me4), 54.6 (Cipso, C5Me4), 131.9, 135.9, 137.6, 138.4
(C5Me4).
Me4(SiMe3)] as a white solid. Methyltrichlorosilane
(6.30 ml, 54 mmol) was added at once to a solution of
Li[C5Me4(SiMe3)] (5.41 g, 27 mmol) in THF (175 ml) at
ꢃ
/
78 8C. The reaction mixture was slowly warmed to r.t.
3.5. Synthesis of C5Me4H[SiMeH(NHtBu)] (4)
and was stirred for 48 h to ensure complete reaction.
After THF removal, the residue was extracted into
NHt2Bu (12.4 ml, 118 mmol) was added to a solution
hexane (2ꢄ/75 ml). The hexane solvent was removed
of 3 (11.83 g, 58.9 mmol) in THF (250 ml) at ꢃ78 8C.
/
under vacuum to give 1 as a pale yellow solid (7.8 g, 25.4
mmol, 94% yield). Anal. Calc. for C13H24Cl2Si2: C,
1
50.79; H, 7.87. Found: C, 50.60; H, 7.92%. H-NMR
After warming to r.t., the reaction mixture was stirred
for 17 h. The volatiles were removed under reduced
pressure and the residue was extracted into hexane (2ꢄ
/
(300 MHz, C6D6, 25 8C): d 0.10 (s, 9H, SiMe3), 0.20 (s,
3H, SiMeCl2), 1.69 (s, 6H, C5Me4), 2.07 (s, 6H, C5Me4).
1H-NMR (300 MHz, CDCl3, 25 8C): d 0.04 (s, 9H,
SiMe3), 0.26 (s, 3H, SiMeCl2), 1.83 (s, 6H, C5Me4), 2.08
(s, 6H, C5Me4). 13C{1H}-NMR (75 MHz, CDCl3,
100 ml). After filtration, solvent was removed under
vacuum to give 4 as a yellow oil (13 g, 54.7 mmol, 93%
yield). Anal. Calc. for C14H27NSi: C, 70.81; H, 11.46; N,
1
5.90. Found: C, 70.43; H, 11.41; N, 5.50%. H-NMR
(300 MHz, C6D6, 25 8C): d ꢃ
/
0.15 (d, 3H, SiMe, Jꢀ3
/
25 8C): d ꢃ
/
0.5 (SiMe3), 3.3 (SiMeCl2), 11.6, 15.0
Hz), 0.29 (br s, 1H, NH), 1.11 (s, 9H, NtBu), 1.82 (s,
3H, C5Me4), 1.85 (s, 3H, C5Me4), 2.00 (s, 3H, C5Me4),
2.05 (s, 3H, C5Me4), 2.91 (br s, 1H, C5Me4H), 4.98 (m,
(C5Me4), 58.3 (Cipso, C5Me4), 131.0, 140.8 (C5Me4).
3.3. Synthesis of [Zr(h5-C5Me4SiMeCl2)Cl3] (2)
1H, SiH). 1H-NMR (300 MHz, CDCl3, 25 8C): d ꢃ
0.27
/
(d, 3H, SiMe, Jꢀ3 Hz), 0.40 (br s, 1H, NH), 1.16 (s,
/
A solution of 1 (3.00 g, 9.75 mmol) in toluene (10 ml)
was added to a suspension of ZrCl4 (2.27 g, 9.75 mmol)
in toluene (35 ml). The Schlenk was connected to a
bubbler and the reaction mixture was warmed at 100 8C
for 3 h. The formation of a brown solution was observed
when the ZrCl4 reacted gradually. After filtration, the
9H, NtBu), 1.80 (2s, 6H, C5Me4), 1.93 (s, 3H, C5Me4),
1.98 (s, 3H, C5Me4), 2.92 (br s, 1H, C5Me4H), 4.69 (m,
1H, SiH). 13C{1H}-NMR (75 MHz, CDCl3, 25 8C): d ꢃ
/
5.5 (SiMe), 11.0, 11.1, 13.6, 13.9 (C5Me4), 33.2 (NtBu),
49.1 (Cipso, NtBu), 55.5 (Cipso, C5Me4), 131.7, 132.9,
135.3, 135.4 (C5Me4).

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A.B. Va´zquez, P. Royo / Journal of Organometallic Chemistry 671 (2003) 172ꢁ178
/
3.6. Synthesis of Li2[C5Me4SiMeH(NtBu)] (5)
3H, ZrMe), 0.02 (s, 3H, ZrMe), 0.51 (d, 3H, SiMe, Jꢀ
/
3.3 Hz), 1.40 (s, 9H, NtBu), 1.89 (2s, 6H, C5Me4), 1.95
(s, 3H, C5Me4), 2.09 (s, 3H, C5Me4), 5.62 (q, 1H, SiH,
A 1.6 M solution of LinBu in hexane (78 ml, 124
mmol) was added dropwise, at ꢃ
/
78 8C, to a solution of
Jꢀ
3.3 Hz). 13C{1H}-NMR (75 MHz, C6D6, 25 8C): d
/
4 (12.25 g, 51.6 mmol) in diethyl ether (200 ml). The
reaction mixture was slowly warmed to r.t. and stirred
for 18 h. A white precipitate was formed which after
3.4 (SiMe), 11.2, 11.4, 12.8, 14.0 (C5Me4), 33.7 (NtBu),
36.0, 37.0 (ZrMe), 54.5 (Cipso, NtBu), 92.7 (Cipso
C5Me4), 125.6, 125.9, 130.5, 130.6 (C5Me4).
,
filtration was washed with hexane (2ꢄ50 ml) and dried
/
under vacuum to give 5 as a white solid (12.34 g, 49.5
mmol, 96% yield). Anal. Calc. for C14H25Li2NSi: C,
67.44; H, 10.11; N, 5.62. Found: C, 67.08; H, 10.15; N,
5.48%.
3.9. Synthesis of [Zr(h5-C5Me4SiMeH-h1-
NtBu)(CH2Ph)2] (8)
A 2 M solution of MgClBz in THF (2.9 ml, 5.8 mmol)
was added to a solution of 6 (1.11 g, 2.8 mmol) in diethyl
3.7. Synthesis of [Zr(h5-C5Me4SiMeH-h1-NtBu)Cl2]
(6)
ether (80 ml) cooled at ꢃ78 8C. The reaction mixture
/
was slowly warmed to r.t. and then stirred for 16 h. The
volatiles were removed under reduced pressure and the
residue was extracted into hexane (100 ml). After
filtration, the solution was concentrated to 10 ml and
Toluene (70 ml) at 0 8C was added to a mixture of 5
(2.69 g, 10.8 mmol) and ZrCl4(THF)2 (4.07 g, 10.8
mmol). The reaction mixture was warmed to r.t. and
then stirred for 2 days. The volatiles were removed
under reduced pressure and the residue was extracted
cooled to ꢃ30 8C to give a yellow solid characterized as
/
8 (1.02 g, 2 mmol, 71% yield). Anal. Calc. for
C28H39NSiZr: C, 66.08; H, 7.72; N, 2.75. Found: C,
1
66.17; H, 7.90; N, 2.67%. H-NMR (300 MHz, C6D6,
into hexane (2ꢄ/100 ml). After filtration, the solution
was concentrated and cooled at ꢃ
/
30 8C to give a yellow
25 8C): d 0.49 (d, 3H, SiMe, Jꢀ
NtBu), 1.54 (d, 1H, TiCH2Ph, Jꢀ
10.8 Hz), 1.71 (d, 1H,
TiCH2Ph, Jꢀ11.1 Hz), 1.74 (2s, 6H, C5Me4), 1.90 (d,
1H, TiCH2Ph, Jꢀ10.8 Hz), 1.91 (s, 3H, C5Me4), 1.94
(d, 1H, TiCH2Ph, Jꢀ11.1 Hz), 2.05 (s, 3H, C5Me4),
5.56 (q, 1H, SiH, Jꢀ3 Hz), 6.78ꢁ7.15 (m, 10H, Ph).
13C{1H}-NMR (75 MHz, C6D6, 25 8C): d 3.3 (SiMe),
11.1, 11.4, 12.9, 14.1 (C5Me4), 33.1 (NtBu), 56.2 (Cipso
/
3 Hz), 1.14 (s, 9H,
solid characterized as 6 (3.09 g, 7.77 mmol, 72% yield).
Anal. Calc. for C14H25Cl2NSiZr: C, 42.30; H, 6.34; N,
3.52. Found: C, 42.47; H, 6.44; N, 3.70%. 1H-NMR (300
/
/
/
MHz, C6D6, 25 8C): d 0.45 (d, 3H, SiMe, Jꢀ3.3 Hz),
/
/
1.32 (s, 9H, NtBu), 1.91 (s, 3H, C5Me4), 1.92 (s, 3H,
C5Me4), 1.99 (s, 3H, C5Me4), 2.13 (s, 3H, C5Me4), 5.60
/
/
1
3.3 Hz). H-NMR (300 MHz, CDCl3,
(q, 1H, SiH, Jꢀ
/
,
25 8C): d 0.69 (d, 3H, SiMe, Jꢀ
NtBu), 2.15 (s, 3H, C5Me4), 2.18 (3s, 9H, C5Me4), 5.52
(q, 1H, SiH, Jꢀ
3.3 Hz). 13C{1H}-NMR (75 MHz,
C6D6, 25 8C): d 2.6 (SiMe), 11.6, 11.9, 13.3, 14.4
/
3.3 Hz), 1.38 (s, 9H,
NtBu), 61.8, 61.9 (TiCH2Ph), 94.9 (Cipso, C5Me4),
122.0, 122.4, 127.2, 127.3, 129.0, 129.3 (Ph), 126.6,
128.6, 130.4 (C5Me4, one not observed), 146.2, 147.3
(Cipso, Ph).
/
(C5Me4), 32.5 (NtBu), 56.3 (Cipso, NtBu), 98.1 (Cipso
,
C5Me4), 131.9, 132.0, 134.5, 134.5 (C5Me4). 13C{1H}-
NMR (75 MHz, CDCl3, 25 8C): d 2.6 (SiMe), 11.8,
3.10. Synthesis of [Zr(h5-C5Me4SiMeH-h1-
NtBu)(NMe2)2] (9)
12.0, 13.3, 14.4 (C5Me4), 32.5 (NtBu), 56.4 (Cipso
,
NtBu), 98.0 (Cipso, C5Me4), 131.8, 131.9, 134.5, 134.5
(C5Me4). 29Si{1H}-NMR (59.6 MHz, CDCl3, 25 8C): d
Toluene (40 ml) at ꢃ78 8C was added to a mixture of
/
ꢃ
/
40.76.
6 (0.24 g, 0.61 mmol) and LiNMe2 (0.062 g, 1.22 mmol).
The reaction mixture was warmed to r.t. and stirred for
21 h. The solvent was removed under vacuum and the
residue was extracted into hexane (40 ml). After filtra-
tion, the solvent was evaporated under vacuum to give 9
as a yellow solid (0.24 g, 0.58 mmol, 95% yield). Anal.
Calc. for C18H37N3SiZr: C, 52.12; H, 8.99; N, 10.13.
Found: C, 51.24; H, 8.88; N, 9.20%. 1H-NMR (300
3.8. Synthesis of [Zr(h5-C5Me4SiMeH-h1-NtBu)Me2]
(7)
A 3 M solution of MgClMe in THF (1.6 ml, 4.6
mmol) was added to a solution of 6 (0.92 g, 2.3 mmol) in
diethyl ether (40 ml) cooled at ꢃ78 8C. The reaction
/
mixture was slowly warmed to r.t. and then stirred for
16 h. The volatiles were removed under reduced pressure
and the residue was extracted into hexane (50 ml). After
filtration, solvent was removed under vacuum to give 7
as an analytically pure orange waxy solid (0.79 g, 2.2
mmol, 96% yield). Anal. Calc. for C16H31NSiZr: C,
53.87; H, 8.76; N, 3.93. Found: C, 54.11; H, 8.88; N,
MHz, C6D6, 25 8C): d 0.71 (d, 3H, SiMe, Jꢀ3 Hz),
/
1.34 (s, 9H, NtBu), 1.86 (s, 3H, C5Me4), 1.89 (s, 3H,
C5Me4), 2.11 (s, 3H, C5Me4), 2.27 (s, 3H, C5Me4), 2.80
(s, 6H, ZrNMe2), 2.86 (s, 6H, ZrNMe2), 5.88 (q, 1H,
SiH, Jꢀ
3 Hz). 13C{1H}-NMR (75 MHz, C6D6, 25 8C):
/
d 4.4 (SiMe), 10.9, 11.1, 12.7, 13.5 (C5Me4), 33.9
(NtBu), 44.1, 44.7 (ZrNMe2), 55.6 (Cipso, NtBu), 97.7
(Cipso, C5Me4), 124.4, 125.5, 127.1 (2) (C5Me4).
1
4.07%. H-NMR (300 MHz, C6D6, 25 8C): d 0.01 (s,

A.B. Va´zquez, P. Royo / Journal of Organometallic Chemistry 671 (2003) 172ꢁ
/178
177
3.11. Synthesis of [Zr(h5-C5Me4SiMeH-h1-
NtBu)Cl(C6F5)] (10)
pentane (100 ml). The pentane solution was concen-
trated to 10 ml and cooled to ꢃ30 8C to give a pale
yellow solid characterized as 12 (1.35 g, 3.1 mmol, 72%
/
A 1.02 M solution of MgCl(C6F5) in diethyl ether (4.0
ml, 4.0 mmol) was added to a solution of 6 (0.8 g, 2
yield). Anal. Calc. for C14H24Cl3NSiZr: C, 38.92; H,
1
5.60; N, 3.24. Found: C, 39.02; H, 5.64; N, 3.03%. H-
mmol) in diethyl ether (50 ml) cooled at ꢃ
/
78 8C. The
NMR (300 MHz, C6D6, 25 8C): d 0.71 (s, 3H, SiMeCl),
1.38 (s, 9H, NtBu), 1.85 (s, 3H, C5Me4), 1.86 (s, 3H,
reaction mixture was slowly warmed to r.t. and then
stirred for 16 h. The volatiles were removed under
reduced pressure and the residue was extracted into
hexane (60 ml). After filtration, the solution was
1
C5Me4), 1.87 (s, 3H, C5Me4), 2.27 (s, 3H, C5Me4). H-
NMR (300 MHz, CDCl3, 25 8C): d 0.96 (s, 3H,
SiMeCl), 1.46 (s, 9H, NtBu), 2.13 (s, 3H, C5Me4),
2.20 (s, 3H, C5Me4), 2.21 (s, 3H, C5Me4), 2.26 (s, 3H,
C5Me4). 13C{1H}-NMR (75 MHz, C6D6, 25 8C): d 9.3
(SiMeCl), 11.7, 11.9, 14.5, 14.6 (C5Me4), 32.9 (NtBu),
57.1 (Cipso, NtBu), 101.8 (Cipso, C5Me4), 130.5, 132.6,
132.8, 135.7 (C5Me4). 13C{1H}-NMR (75 MHz, CDCl3,
25 8C): d 9.3 (SiMeCl), 11.9, 12.1 14.5 14.6 (C5Me4),
32.9 (NtBu), 57.2 (Cipso, NtBu), 101.6 (Cipso, C5Me4),
130.5, 132.5, 132.8 135.7 (C5Me4). 29Si{1H}-NMR (59.6
concentrated to 10 ml and cooled to ꢃ30 8C to give a
/
yellow solid characterized as the monoalkylated product
10 (0.75 g, 1.42 mmol, 71% yield). Anal. Calc. for
C20H25ClF5NSiZr: C, 45.40; H, 4.76; N, 2.65. Found: C,
1
44.55; H, 4.46; N, 2.77%. H-NMR (300 MHz, C6D6,
25 8C): d 0.47 (d, 3H, SiMe, Jꢀ
SiMe, Jꢀ
3.3 Hz), 1.39 (2s, 18H, NtBu), 1.47, 1.49,
1.67, 1.83, 2.05, 2.06, 2.07, 2.21 (8s, 24H, C5Me4), 5.58
3.3 Hz).
/3.3 Hz), 0.51 (d, 3H,
/
(q, 1H, SiH, Jꢀ
/
3.3 Hz), 5.62 (q, 1H, SiH, Jꢀ
/
MHz, CDCl3, 25 8C): d ꢃ23.15.
/
13C{1H}-NMR (75 MHz, C6D6, 25 8C): d 2.5, 3.1
(SiMe), 11.6, 11.7, 12.6, 12.9, 13.7, 14.6, 14.7, 15.8
(C5Me4), 32.5, 32.8 (NtBu), 58.3, 58.4 (Cipso, NtBu),
96.9, 97.2 (Cipso, C5Me4), 131.4, 131.5, 132.1, 132.4,
135.3, 135.6, 135.7 (C5Me4, one not observed).
3.14. Synthesis of [Zr(h5-C5Me4SiMeCl-h1-
NtBu)Me2] (13)
A 3 M solution of MgClMe in THF (0.76 ml, 2.28
mmol) was added to a solution of 12 (0.49 g, 1.14 mmol)
3.12. Synthesis of [Zr(h5-C5Me4SiMeH-h1-
NtBu)Cl{N(SiMe3)2}] (11)
in diethyl ether (40 ml) cooled at ꢃ78 8C. The reaction
/
mixture was slowly warmed to r.t. and then stirred for
15 h. The volatiles were removed under reduced pressure
and the residue was extracted into pentane (40 ml). After
filtration, solvent was removed under vacuum to give 13
as a pale yellow solid (0.29 g, 0.74 mmol, 65% yield).
Anal. Calc. for C16H30ClNSiZr: C, 49.13; H, 7.73; N,
3.58. Found: C, 48.77; H, 7.67; N, 3.85%. 1H-NMR (300
A mixture of 6 (0.62 g, 1.56 mmol) and LiN(SiMe3)2
(0.26 g, 1.56 mmol) in toluene (35 ml) was stirred at
100 8C for 18 h. The volatiles were removed under
reduced pressure and the residue was extracted into
hexane (60 ml). After filtration, solvent was removed
under vacuum to give 11 as a yellow solid (0.74 g, 1.42
mmol, 91% yield). Anal. Calc. for C20H43ClN2Si3Zr: C,
45.97; H, 8.29; N, 5.36. Found: C, 46.05; H, 8.32; N,
MHz, C6D6, 25 8C): d ꢃ0.04 (s, 3H, ZrMe), 0.04 (s, 3H,
/
ZrMe), 0.75 (s, 3H, SiMeCl), 1.45 (s, 9H, NtBu), 1.80
(2s, 6H, C5Me4), 1.81 (s, 3H, C5Me4), 2.23 (s, 3H,
C5Me4). 13C{1H}-NMR (75 MHz, C6D6, 25 8C): d 9.9
(SiMeCl), 11.2, 11.3, 14.0, 14.1 (C5Me4), 34.0 (NtBu),
1
5.10%. H-NMR (300 MHz, C6D6, 25 8C): d 0.28 (s,
9H, N(SiMe3)), 0.30 (s, 9H, N(SiMe3)), 0.38 (2s, 18H,
N(SiMe3)2), 0.61 (2d, 6H, SiMeH, Jꢀ
18H, NtBu), 1.89, 1.91, 2.02, 2.03, 2.13, 2.13, 2.26, 2.26
(8s, 24H, C5Me4), 5.64 (q, 1H, SiH, Jꢀ3.3 Hz), 5.75 (q,
1H, SiH, Jꢀ
3.3 Hz). 13C{1H}-NMR (75 MHz, C6D6,
/3.3 Hz), 1.40 (2s,
37.7, 38.7 (ZrMe), 55.3 (Cipso, NtBu), 95.9 (Cipso
C5Me4), 124.7, 125.9, 128.5, 131.7 (C5Me4).
,
/
/
3.15. Synthesis of [Zr(h5-C5Me4SiMeCl-h1-
NtBu)Cl{N(SiMe3)2}] (14)
25 8C): d 3.4, 3.8 (SiMeH), 5.9 (2), 7.1, 7.3 (N(SiMe3)2),
12.5, 12.6, 12.8, 14.4, 14.5, 15.2, 15.6, 15.9 (C5Me4),
32.3, 32.3 (NtBu), 56.9, 57.0 (Cipso, NtBu), 98.0, 99.2
(Cipso, C5Me4), 126.1, 126.5, 127.1, 131.3, 131.8, 131.9,
133.4, 133.8 (C5Me4).
A mixture of 12 (0.44 g, 1.02 mmol) and LiN(SiMe3)2
(0.17 g, 1.02 mmol) in toluene (30 ml) was stirred at
105 8C for 20 h. The volatiles were removed under
reduced pressure and the residue was extracted into
hexane (40 ml). After filtration, solvent was removed
under vacuum to give 14 as a pale yellow solid (0.55 g,
3.13. Synthesis of [Zr(h5-C5Me4SiMeCl-h1-NtBu)Cl2]
(12)
0.99
mmol,
97%
yield).
Anal.
Calc.
for
A 1 M solution of BCl3 in heptane (4.4 ml, 4.33 mmol)
was added to a solution of 6 (1.72 g, 4.33 mmol) in
C20H42Cl2N2Si3Zr: C, 43.13; H, 7.60; N, 5.03. Found:
C, 43.48; H, 7.71; N, 4.76%. 1H-NMR (300 MHz, C6D6,
25 8C): d 0.20 (s, 9H, N(SiMe3)), 0.33 (s, 9H, N(SiMe3)),
0.36 (2s, 18H, N(SiMe3)2), 0.86 (s, 3H, SiMeCl), 0.91 (s,
3H, SiMeCl), 1.44 (s, 9H, NtBu), 1.50 (s, 9H, NtBu),
CH2Cl2 (45 ml) cooled at ꢃ78 8C. The reaction mixture
/
was slowly warmed to r.t. and then stirred for 16 h. The
solvent was removed and the residue was extracted into

178
A.B. Va´zquez, P. Royo / Journal of Organometallic Chemistry 671 (2003) 172ꢁ178
/
[6] (a) P.J. Shapiro, E. Bunel, W.P. Schaefer, J.E. Bercaw, Organo-
metallics 9 (1990) 867;
(b) J. Okuda, Chem. Ber. 123 (1990) 1649;
1.83, 1.85, 1.96, 1.96, 1.98, 2.00, 2.40, 2.46 (8s, 24H,
C5Me4). 13C{1H}-NMR (75 MHz, C6D6, 25 8C): d 5.4,
5.5, 6.6, 6.7 (N(SiMe3)2), 9.9, 10.3 (SiMeCl), 12.1, 12.2,
12.3, 12.3, 14.3, 15.2, 15.3, 15.6 (C5Me4), 32.2, 32.4
(c) P.J. Shapiro, W.D. Cotter, W.P. Schaefer, J.A. Labinger, J.E.
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(d) K.E. du Plooy, U. Moll, S. Wocadlo, W. Massa, J. Okuda,
Organometallics 14 (1995) 3129;
(NtBu), 57.1, 57.4 (Cipso, NtBu), 101.1, 102.4 (Cipso
,
C5Me4), 124.7, 126.8, 130.2, 130.9, 131.8, 132.4, 132.7,
134.9 (C5Me4).
(e) F. Amor, A. Butt, K.E. du Plooy, T.P. Spaniol, J. Okuda,
Organometallics 17 (1998) 5836;
(f) J. Okuda, T. Eberle, T.P. Spaniol, V. Piquet-Faure´, J.
Organomet. Chem. 591 (1999) 127.
[7] T. Cuenca, P. Royo, Coord. Chem. Rev. 193ꢁ195 (1999) 447.
[8] S. Ciruelos, T. Cuenca, R. Go´mez, P. Go´mez-Sal, A. Manzanero,
P. Royo, Organometallics 15 (1996) 5577.
/
Acknowledgements
We thank Ministerio de Ciencia y Tecnolog´ıa for
support of this work (Project MCyT-MAT2001-1309
and predoctoral fellowship to A.B.V.
[9] B. Royo, P. Royo, L.M. Cadenas, J. Organomet. Chem. 551
(1998) 293.
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