The tendency of tripodal amidozirconium and hafnium complexes to form hexacoordinate structures: Alkali metal halide cages versus solvent adducts

Article abstract of DOI:10.1016/S0022-328X(99)00486-6

Reaction of the tripodal lithium amide [HC{SiMe₂N(Li)(4-CH₃C₆H₄)} ₃] with ZrCl₄ in diethyl ether gave the chlorozirconium-lithum chloride complex [HC{SiMe₂N(4-CH₃C

Full text of DOI:10.1016/S0022-328X(99)00486-6

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Journal of Organometallic Chemistry 591 (1999) 71–77
The tendency of tripodal amidozirconium and hafnium complexes
to form hexacoordinate structures: alkali metal halide cages versus
solvent adducts
Patrick Renner a,b, Christian Galka a,b, Harald Memmler b, Uta Kauper b,
Lutz H. Gade a,*
a Laboratoire de Chimie Organome´tallique et de Catalyse, Institut Le Bel, Uni6ersite´ Louis Pasteur, 4, rue Blaise Pascal,
F-67070 Strasbourg Ce´dex, France
b Institut fu¨r Anorganische Chemie and Institut fu¨r Organische Chemie der Uni6ersita¨t Wu¨rzburg, Am Hubland, D-97074 Wu¨rzburg, Germany
Received 5 July 1999; accepted 6 August 1999
Abstract
Reaction of the tripodal lithium amide [HC{SiMe2N(Li)(4-CH3C6H4)}3] with ZrCl4 in diethylether gave the chlorozirconium–
lithum chloride complex [HC{SiMe2N(4-CH3C6H4)}3Zr{Cl4(LiꢀOEt2)3}] (3). This contains a metal halide heterocubane unit fused
to the tripodal amido cage through the hexacoordinate zirconium atom as established by an X-ray diffraction study.
Recrystallisation of the compound in THF gives the hexacoordinate solvent adduct [HC{SiMe2N(4-CH3C6H4)}3ZrCl(THF)2] (4)
which was also characterized by X-ray crystallography. Alkylation of the chloro complex [HC{SiMe2N(2-FC6H4)}3Zr((-
Cl)2Li(OEt2)2] (2a) with methyllithium or t-butyllithium yields the alkylcomplexes [HC{SiMe2N(2-FC6H4)}3ZrCH3] (6) and
[HC{SiMe2N(2-FC6H4)}3ZrC(CH3)3] (7) for which the JFH and JFC coupling with the metal-bound alkyl groups indicates
involvement of the peripheral fluoro functions in the coordination to the metal centre. © 1999 Elsevier Science S.A. All rights
reserved.
Keywords: Zirconium; Hafnium; Tripodal amide; Heterocubane; Alkyl
The more exposed nature of the central atom in these
species, compared with the Ti analogues, generally im-
plies an increased sensitivity towards hydrolysis or
degradation by other protic species. The latter can be
partially suppressed by incorporation of weakly coordi-
nating functionalities into the ligand periphery, such as
achieved in the tripodal amides containing a 1-
fluorophenyl periphery [6]. Their effect has been evident
in the synthesis of the analogues of compound 1 which
yielded products of the same composition [E{SiMe2N-
(2-FC6H4)}3Zr(m-Cl)2Li(OEt2)2] (E=HC: 2a, MeSi: 2b)
[5,6]. Single-crystal X-ray structure analyses of both
compounds established hexacoordinate structures in
which one of the fluorophenyl groups is weakly coordi-
nated to the metal centre.
1. Introduction
Triamidochloro complexes of the Ti-triad metals co-
ordinated by tripodal triamido ligands have been found
to be versatile organometallic reagents and molecular
building blocks [1–4]. Whereas the titanium complexes
usually adopt a four-coordinate distorted tetrahedral
geometry, the greater ionic radius of its heavier con-
geners, zirconium and hafnium, render them more sus-
ceptible to an increase in the coordination number by
addition of one or two further ligands. This was for
instance observed in the reaction of the lithium amide
[MeSi{SiMe2N(Li)(4-MeOC6H4)}3] with ZrCl4 in di-
ethyl ether, which yielded the pentacoordinate complex
[MeSi{SiMe2N(4-MeOC6H4)}3Zr((–Cl)2Li(OEt2)2] (1)
(Fig. 1) [5].
In this paper we report further studies concerning the
tendency towards an expansion of the coordination
sphere in the heavier Ti-group metal complexes. In
particular, we show how the presence of the alkali
* Corresponding author. Fax: +33-388-415-6045.
E-mail address: gade@chimie.u-strasbg.fr (L.H. Gade)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00486-6

72
P. Renner et al. / Journal of Organometallic Chemistry 591 (1999) 71–77
Fig. 1. Molecular structures of the pentacoordinate complex 1 and the hexacoordinate complexes 2a/b.
metal salt generated in the salt methathesis of the
lithium amide with the metal halide as well as the
presence of a donor solvent affects the structure of the
isolated product.
lish its structure unambiguously, a single-crystal X-ray
structure analysis was carried out. The molecular struc-
ture of the complex is displayed in Fig. 2 while the
principal bond lengths and interbond angles are listed
in Table 1.
2. Results and discussion
2.1. Synthesis and single-crystal X-ray structure
analyses of [HC{SiMe2N(4-CH3C6H4)}3Zr-
{Cl4(LiꢀOEt2)3}] (3) and [HC{SiMe2N(4-CH3-
C6H4)}3ZrCl(THF)2] (4)
Reaction of the lithium amide [HC{SiMe2N(Li)(4-
CH3C6H4)}3] [1c] with one molar equivalent of ZrCl4 in
diethylether yielded a zirconium amide derivative which
remained dissolved along with more than 90% of the
theoretical amount of LiCl to be formed in this conver-
sion. From this solution a highly crystalline, colourless
solid could be isolated by crystallization. The analytical
data were consistent with its formulation as
[HC{SiMe2N(4-CH3C6H4)}3ZrCl{ClLiꢀOEt2)3}] (3), i.e.
the adduct of the triamidochlorozirconium complex
with three units of ether-solvated lithium chloride. The
1H-, 13C- and 29Si-NMR spectra of the compound,
recorded at 295 K in C6D6 indicate an effective three-
fold molecular symmetry in solution. In order to estab-
Fig. 2. View of the molecular structure of 3 perpendicular (a) and
along (b) the threefold molecular axis.

P. Renner et al. / Journal of Organometallic Chemistry 591 (1999) 71–77
73
Table 1
The heterocubane is a fairly common structural motif
in alkalimetal chemistry [7] although we are unaware of
derivatives incorporating a transition metal. The most
prominent examples are the alkyllithium tetramers such
as (LiEt)4 and (LiR)4(L)2 (e.g. R=Me, L=te-
tramethylethylenediamine) [8,9], imidolithium com-
plexes such as [Ph2=NLi·NC5H5]4 [10] as well as
lithium enolates [11], e.g. the tetrahydofuran complex
[Li(THF)OtBuCꢁCH2]4 [12]. The structurally most
closely related compound is the tetrameric
[ClLi·OꢁP(NMe2)3]4 reported by Snaith and co-work-
ers, which contains a central (LiCl)4 cube [10]. While
the Li–Cl distances lie in the same range as for com-
,
Selected bond lengths (A) and interbond angles (°) of 3
Bond lengths
Zr(1)ꢀN(1)
Zr(1)ꢀN(2)
Zr(l)ꢀN(3)
Zr(1)ꢀCl(l)
Zr(1)ꢀCl(2)
2.082(2)
2.080(2)
2.081(2)
2.6553(11)
2.6581(15)
Zr(1)ꢀCl(3)
Li(l)ꢀCl(2)
Li(1)ꢀCl(l)
Li(1)ꢀCl(4)
Li(1)ꢀO(1)
2.6921(12)
2.373(5)
2.396(5)
2.351(6)
1.885(6)
Bond angles
N(1)ꢀZr(1)ꢀN(2)
N(1)ꢀZr(1)ꢀN(3)
N(2)ꢀZr(1)ꢀN(3)
Cl(1)ꢀZr(1)ꢀCl(2) 79.28(4)
Cl(1)ꢀZr(1)ꢀCl(3) 80.72(4)
97.61 (9)
99.79(9)
97.09(9)
Cl(2)ꢀZr(1)ꢀCl(3)
Li(1)ꢀCl(4)ꢀLi(3)
Li(1)ꢀCl(4)ꢀLi(2)
Li(2)ꢀCl(4)ꢀLi(3)
80.73(4)
80.57(19)
81.60(19)
82.77(18)
,
pound 3 (2.35–2.44 A), the cuboidal core is somewhat
less distorted than observed upon incorporation of an
early transition metal.
If the recrystallization of complex 3 is carried out in
THF, the increased polarity and donor properties of
the solvent lead to a disintegration of the alkali metal
halide cube. The compound isolated upon crystalliza-
tion is the bis(THF) adduct of the triamidomonohalide,
[HC{SiMe2N(4-CH3C6H4)}3ZrCl(THF)2] (4) as estab-
lished by elemental analysis. The observation of reso-
nance patterns in the NMR spectra of the compound
which are consistent with an effective threefold molecu-
lar symmetry indicate configurational instability of the
complex. This is thought to exchange the THF and Cl
ligand positions via dissociation of a THF molecule
and rearrangement of the pentacoordinate intermedi-
ate. While considerable resonance broadening is ob-
served upon lowering the temperature of a sample in
toluene-d8, the dynamic process could not be frozen
out.
The hexacoordinate structure of complex 4, deduced
from the analytical and spectroscopic data, could be
established by an X-ray diffraction study. Two views of
the molecular structure are given in Fig. 3 while the
principal bond lengths and interbond angles are listed
in Table 2.
The overall structure of the tripod ligand cage is very
similar to that of 3, however, there is a marked differ-
ence between the three amido–N–Zr distances.
Whereas the bond lengths Zr(1)–N(1) and Zr–N(3) lie
in the same range as those observed in the structure of
The main structural feature established for com-
pound 3 is the combination of two cage units that are
fused through a joint vertex occupied by the zirconium
atom, the [2,2,2]-bicyclooctane-related tripodal triami-
dozirconium moiety and a distorted metallacubane cage
comprising three LiCl and one ZrCl units (Fig. 2(a)).
The tripodal amido ligand shows a helical twist that
may be envisaged as a rotation of the N3 triangle of the
ligand with respect to an Si3 triangle described by the
three SiMe2 units of each tripod arm (Fig. 2(b)). This
situation is thought to be a consequence of the steric
repulsions of the methyl groups in the SiMe2 units. The
three peripheral tolyl groups are twisted in relation to
the Si–N vectors in the amido cage and thus adopt the
lamp shade arrangement also noted for the previously
reported trisilylsilane derivatives [3b,3f]. The zirconium
atom is hexacoordinated in a highly distorted octahe-
dral arrangement generated by the facial coordination
of the tripod ligand and the coordination of three
chloro ligands. The steric constraints of the ligand
backbone enforce an increase in the NꢀZrꢀN% bond
angles with respect to the value of 90° in an octahedral
structure [N(1)ꢀZr(1)ꢀN(2) 97.61(9), N(1)ꢀZr(1)ꢀN(3)
99.79(9), N(2)ꢀZr(1)ꢀN(3) 97.09(9)°]. This situation in
turn induces smaller ClꢀZrꢀCl% bond angles than 90°
[Cl(1)ꢀZr(1)ꢀCl(2) 79.28(4), Cl(1)ꢀZr(1)ꢀCl(3) 80.72(4),
Cl(2)ꢀZr(1)ꢀCl(3) 80.73(4)°] and, as a consequence an
elongation of the cubic cage along the diagonal three-
fold axis going through Zr(1) and Cl(4). The interbond
angles around the Cl(4) atom are in fact very similar to
the values at the zirconium vertex quoted above
[Li(1)ꢀCl(4)ꢀLi(3) 80.57(19), Li(1)ꢀCl(4)ꢀLi(2) 81.60
(19), Li(2)ꢀCl(4)ꢀLi(3) 82.77(18)°], while there is a con-
siderable variation of the angles at the other vertices
ranging from 80 to 101°. The three lithium atoms attain
their fourfold coordination geometry by coordination
of one molecule of diethylether per metal atom.
Table 2
,
Selected bond lengths (A) and interbond angles (°) of 4
Bond lengths
Zr(1)ꢀN(1)
Zr(1)ꢀN(2)
Zr(1)ꢀN(3)
2.097(2)
2.124(2)
2.096(3)
Zr(1)ꢀCl(1)
Zr(1)ꢀO(l)
Zr(1)ꢀO(2)
2.4991 (8)
2.356(2)
2.343(2)
Bond angles
N(1)ꢀZr(l)ꢀN(2) 97.68(10)
N(1)ꢀZr(l)ꢀN(3) 96.80(10)
N(2)ꢀZr(l)ꢀN(3) 96.29(10)
0(2)ꢀZr(1)ꢀO(1)
Cl(1)ꢀZr(1)ꢀO(2)
Cl(l)ꢀZr(l)ꢀO(1)
82.36(9)
76.49(6)
80.93(6)

74
P. Renner et al. / Journal of Organometallic Chemistry 591 (1999) 71–77
[HC{SiMe2N(Li)(2-FC6H4)}3] [6] with HfCl4 in diethyl
ether. While the synthesis of the corresponding zirco-
nium complex yielded the hexacoordinate LiCl-adduct
2a [5], the reaction with hafnium tetrachloride gave the
bis(diethylether)complex 5 (Scheme 1).
2.2. Synthesis [HC{SiMe2N(2-FC6H4)}3ZrCH3] (6) and
[HC{SiMe2N(2-FC6H4)}3ZrC(CH3)3] (7)
Reaction of [HC{SiMe2N(2-FC6H4)}3Zr(m-Cl)2Li-
(OEt2)2] (2a) [5] with one molar equivalent of methyl-
lithium or t-butyllithium gave the alkylzirconium com-
plexes [HC{SiMe2N(2-FC6H4)}3ZrCH3] (6) and
[HC{SiMe2N(2-FC6H4)}3ZrC(CH3)3] (7), respectively
(Scheme 2). Both compounds are thermally very stable
and do not decompose in solution at temperatures up
to 80°C.
1
The H- and 13C-NMR spectra support the proposed
threefold symmetrical molecular structure displayed in
Scheme 2. In particular, the signal assigned to the
protons of the metal-bonded methyl group in 6, ob-
served at (0.65 is split as a quartet resonance due to
coupling with the three fluorine nuclei (3JFH=8.4 Hz).
This observation may be interpreted as providing evi-
dence for the involvement of the three peripheral
fluorine atoms to the metal centre. Coupling with the
fluorine nuclei is also observed in the 13C-NMR spectra
of 6 and 7. In both cases a quartet splitting is observed
for the resonance due to the 13C nucleus bound to the
zirconium atom (6: (47.3, 2JFC=4.6 Hz; 7: (67.2,
2JFC=3.0 Hz). In both cases, this is consistent with the
involvement of the peripheral fluorine atoms in the first
coordination sphere of the central metal atoms, reflect-
ing the tendency of zirconium to adopt coordination
numbers higher than four.
Fig. 3. View of the molecular structure of 4 perpendicular (a) and
along (b) the molecular axis of the metal-tripod cage.
complex
3 [Zr(1)–N(1) 2.097(2) and Zr(1)–N(3)
,
,
2.096(3) A] the value of Zr(1)–N(1) of 2.124(2) A is
significantly greater and probably a consequence of the
stronger trans influence of the chloro ligand in compari-
son to the two THF ligands. This observation is com-
plemented by the shorter Zr(1)–Cl(1) distance of
2.4991(8) compared to the corresponding values in the
formally dianionic Cl3Zr(tripod) unit of 3.
3. Experimental
All manipulations were performed under an inert gas
atmosphere of dried argon in standard (Schlenk) glass-
ware, which was flame dried with a Bunsen burner
prior to use. Solvents were dried according to standard
procedures and saturated with Ar. The deuterated sol-
The structural unit containing two donor molecules
coordinated to the triamidochloro–zirconium complex
established for 4 by X-ray crystallography is also
thought to be present in the reaction product of
Scheme 1. Synthesis of the bis(diethylether) complex 5.

P. Renner et al. / Journal of Organometallic Chemistry 591 (1999) 71–77
75
Scheme 2. Synthesis of the alkylzirconium complexes 6 and 7.
vents used for the NMR spectroscopic measurements
were degassed by three successive ‘freeze–pump–thaw’
{1H}7Li-NMR (77.77 MHz, C6D6, 295 K): l −2.4. IR
(benzene): 3016 (w) cm−1, 2975 (vs), 2922 (s), 2866 (s),
1606 (m), 1512 (vs), 1499 (vs), 1444 (w), 1381 (w), 1368
(w), 1288 (m), 1252 (vs), 1222 (vs), 1118 (s), 1016 (s),
970 (s), 848 (br.vs), 808 (vs), 704 (m), 521 (m).
C40H70N3Cl4Li3O3Si3Zr (979.13): Anal. Calc. C, 49.07;
H, 7.21; N, 4.29; Found C, 48.58; H, 6.85; N, 4.53.
,
cycles and dried over 4 A molecular sieves.
The 1H-, 13C-, 29Si- and 19F-NMR spectra were
recorded on a Bruker AC 200 spectrometer equipped
with a B-VT-2000 variable temperature unit (at 200.13,
50.32, 39.76, and 188.31 MHz, respectively) with te-
tramethylsilane and CFCl3 as references.
3.2. Preparation of
[HC{SiMe2N(4-CH3C6H4)}3ZrCl(THF)2] (4)
Elemental analyses were carried out in the Microana-
lytical Laboratory of the Chemistry Department at
Wu¨rzburg. The ligand precursors HC{SiMe2NH(4-
CH3C6H4)}3 and HC{SiMe2NH(2-FC6H4)}3 were pre-
pared as reported previously [1c,6].
Preparation as for 3. However, recrystallization oc-
cured from THF. Yield: 72%. H-NMR (400.14 MHz,
1
C6D6, 295 K): l −0.32 (s, 1 H, HC(Si…)3), 0.45 (s, 18
H, Si(CH3)2), 1.17 (THF), 2.12 (s, 9 H, CH3C6H4), 3.58
3
(THF), 7.00 (d, 6 H, JHH=7.8 Hz, H2,6 of C6H4), 7.09
3.1. Preparation of
(d, 6 H, H3,5 of C6H4). {1H}13C-NMR (100.62 MHz,
C6D6, 295 K): l 4.5 (Si(CH3)2), 4.9 (HC(Si…)3), 20.7
(CH3C6H4), 25.5 (THF), 69.8 (THF), 124.2 (C2,6 of
C6H4), 130.2 (C3,5 of C6H4), 130.8 (C4 of C6H4), 148.9
(C1 of C6H4). {1H}29Si-NMR (79.50 MHz, C6D6, 295
K): l 1.1. C36H56ClN3O2Si3Zr (773.79): Anal. Calc. C,
55.88; H, 7.29; N, 5.43. Found C, 55.45; H, 7.03; N,
5.49.
[HC{SiMe2N(4-CH3C6H4)}3Zr{Cl4(LiꢀOEt2)3}] (3)
To a solution of HC{SiMe2NH(4-CH3C6H4)}3 (5.63
g=11.13 mmol) in diethyl ether (40 ml) which was
cooled at −78°C were added 14.69 ml of BuLi (2.5 M
solution in N-hexanes=36.73 mmol). After stirring for
5 h, the solution was concentrated to ca. 4 ml and the
lithium amide, which precipitated almost quantitatively,
was isolated by centrifugation. The solid lithium amide
was re-dissolved in ca. 30 ml of diethyl ether, the
solution thus obtained cooled at −78°C and solid
ZrCl4 (2.59 g=11.13 mmol) was subsequently added to
the reaction mixture. After warming to room tempera-
ture (r.t.) and stirring for 14 days, the solution was
concentrated, and a small amount of precipitated LiCl
separated by centrifugation. Storage of the solution at
−25°C yielded colourless crystals of 3. Yield: 5.72 g
3.3. Preparation of
[HC{SiMe2N(2-FC6H4)}3HfCl(OEt2)2] (5)
To a stirred solution of HC{SiMe2NH(2-FC6H4)}3
(2.81 g=5.44 mmol) in 100 ml of diethyl ether, which
was cooled at −78°C, were added dropwise 6.6 ml of
an N-BuLi solution (2.5 M in n-hexane). The reaction
mixture was subsequently warmed to r.t. and stirred for
a further 60 min. The solution obtained was then
re-cooled to −78°C and solid HfCl4 (1.74 mg=5.50
mmol) was added. The reaction mixture was warmed to
ambient temperature over a period of ca 8 h and stirred
for another 2 days. The solid lithium chloride formed in
the reaction was removed by centrifugation. Upon
slowly evaporating the solvent of the centrifugate,
colourless crystals of compound 5 formed, which were
isolated by filtration and dried in vacuo. Yield: 2.52 g
1
(82%). H-NMR (200.13 MHz, C6D6, 295 K): l −0.26
(s, 1 H, HC(Si…)3), 0.45 (s, 18 H, Si(CH3)2), 0.80 (t,
(CH3CH2)2O), 2.15 (s, 9 H, CH3C6H4), 3.21 (q,
(CH3CH2)2O), 6.95–7.13 (m, 12 H, C6H4). {1H}13C-
NMR (50.32 MHz, C6D6, 295 K): l 4.5 (Si(CH3)2), 5.3
(HC(Si…)3), 14.6 ((CH3CH2)2O), 20.9 (CH3C6H4), 66.2
((CH3CH2)2O), 124.8 (C2,6 of C6H4), 130.3 (C3,5 of
C6H4), 130.9 (C1 of C6H4), 149.3 (C1 of C6H4).
{1H}29Si-NMR (39.76 MHz, C6D6, 295 K): l 1.1.

76
P. Renner et al. / Journal of Organometallic Chemistry 591 (1999) 71–77
Table 3
Crystal data and structure refinement for 3 and 4
3
4
Empirical formula
Formula weight
Temperature (K)
C4OH7OCl4Li3N3O3Si3Zr·C4H10
1053.22
153(2)
O
C
773.78
193(2)
36H56ClN3O2Si3Zr
,
Wavelength (A)
0.71073
Triclinic
0.71073
Monoclinic
P21/c
Crystal system
Space group
(
P1
Unit cell dimensions
,
a (A)
12.339(5)
13.579(5)
19.585(8)
78.09(3)
81.69(3)
64.01(4)
2880.8(19), 2
1.214
16.743(2)
17.0148(11)
13.8937(17)
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
97.388(6)
3
,
Volume (A ), Z
3925.0(8), 4
1.309
0.474
1632
Dcalc (g cm−3
)
Absorption coefficient (mm−1
F(000)
)
0.476
1112
Crystal size (mm)
q range for data collection
Limiting indices
Reflections collected
Independent reflections
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R indices (all data)
0.6×0.5×0.5
2.07–24.99
−145h51, −165k514, −235lB23
10664
10118 (Rint=0.0229)
Full-matrix least-squares on F2
10118/662/728
0.8×0.8×0.6
2.16–24.99
−25h519, −35k520, −165l516
9386
6892 (Rint=0.0338)
Full-matrix least-squares on F2
6892/0/424
1.024
1.035
R1=0.0395, wR2=0.0966
R1= 0.0473, wR2=0.1036
0.619 and −0.616
R1= 0.0393, wR2=0.0905
R1=0.0539, wR2=0.0996
0.539 and −0.581
−3
,
Largest diff. peak and hole (e A
)
(53%). M.p.: 75°C (dec.). 1H-NMR (C6D6, 295 K):l
−0.54 (s, HC(Si…)3), 0.37 (s, Si(CH3)2), 1.01 (t,
3JHH=6.8 Hz, OCH2CH3), 3.30 (q, OCH2CH3), 6.46–
6.86 (m, 2-FC6H4). {1H}13C-NMR (C6D6, 295 K):l 4.2
(Si(CH3)2), 5.3 (HC(Si…)3), 15.3 (OCH2CH3), 66.0
centrifugation. Upon slowly evaporating the solvent of
the centrifugate, colourless crystals of compound 6
formed, which were isolated by filtration and dried in
vacuo. Yield: 330 mg (88%). M.p.: 82°C (dec.).
1H-NMR (C6D6, 295 K): l −0.46 (s, HC(Si…)3), 0.37
2
3
(OCH2CH3), 114.7 (d, JFC=22.2 Hz, C3 of 2-FC6H4),
(s, Si(CH3)2), 0.65 (q, JFH=8.4 Hz, H3CꢀZr), 6.44–
2
120.8, 123.7, 125.6 (C4–6 of 2-FC6H4), 139.7 (d, JFC
=
6.85 (m, 2-FC6H4). {1H}13C-NMR (C6D6, 295 K): l 4.3
(Si(CH3)2), 6.3 (HC(Si…)3), 47.3 (q, 2JFC=4.6 Hz,
13.9 Hz, C1 of 2-FC6H4), 159.6 (d, JFC=232.7 Hz, C2
of 2-FC6H4). {1H}19F-NMR (C6D6, 295 K): l −121.3.
{1H}29Si-NMR (C6D6, 295 K): l 3.3. IR (toluene): 1614
(s) cm−1, 1310 (vs), 1260 (m), 1243 (m), 1184 (w), 1120
(w), 1093 (w), 1028 (m), 1004 (m), 898 (m), 847 (s).
C33H51ClF3HfN3Si3O2 (877.98): Anal. Calc. C, 45.15;
H, 5.86; N, 4.79. Found C, 45.19; H, 5.65; N, 4.57.
1
H3CꢀZr), 114.6 (d, 2JFC=22.0 Hz, C3 of 2-FC6H4),
2
120.0, 122.0, 125.9 (C4–6 of 2-FC6H4), 139.8 (d, JFC
=
14.0 Hz, C1 of 2-FC6H4), 158.7 (d, JFC=224.8 Hz, C2
of 2-FC6H4). {1H}19F-NMR (C6D6, 295 K): l −121.3.
IR (Nujol): 1621 (m) cm−1, 1500 (s), 1476 (vs), 1310
(s), 1285 (s), 1266 (s), 1253 (s), 1246 (s) 1062 (m), 1036
(m), 968 (w), 937 (m), 823 (vs), 739 (s), 727 (m).
C26H34F3N3Si3Zr (621.05): Anal. Calc. C, 50.28; H,
5.52; N, 6.77. Found C, 50.11; H, 5.73; N 6.62.
1
3.4. Preparation of [HC{SiMe2N(2-FC6H4)}3ZrCH3]
(6)
To a stirred solution of HC{SiMe2N(2-FC6H4)}3-
ZrCl2Li(OEt2)2 (2a) (500 mg=0.601 mmol) in 20 ml of
diethyl ether, which was cooled at −78°C, were added
dropwise 0.4 ml of a solution of MeLi (1.7 M in
diethylether). Over a period of 3 h, the reaction mixture
was warmed to r.t. and the LiCl that precipitated
during the course of this process was removed by
3.5. Preparation of
[HC{SiMe2N(2-FC6H4)}3ZrC(CH3)3] (7)
To
a
stirred
solution
of
HC{SiMe2N(2-
FC6H4)}3ZrCl2Li(OEt2)2 (2a) (500 mg=0.601 mmol)
20 ml of toluene, which was cooled at −78°C, were
added dropwise 0.5 ml of a solution of t-BuLi (1.5 M in

P. Renner et al. / Journal of Organometallic Chemistry 591 (1999) 71–77
77
4. Supplememtary material
pentane). Over a period of 3 h, the reaction mixture
was warmed to r.t. and the LiCl which precipitated
during the course of this process was removed by
centrifugation. The centrifugate was concentrated to 5
ml and stored at r.t. for several days. During this
period compound 7 crystallized as a colourless solid,
which was isolated by decanting the supernatant solu-
tion and drying in vacuo. Yield: 302 mg (76%). M.p.:
85°C (dec.). 1H-NMR (C6D6, 295 K): l −0.38 (s,
HC(Si…)3), 0.37 (s, Si(CH3)2), 0.97 (d, J=2.1 Hz,
ZrC(CH3)3), 6.85–7.09 (m, 2-FC6H4). {1H}13C-NMR
(C6D6, 295 K): l 4.3 (Si(CH3)2), 8.5 (HC(Si…)3), 26.8
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Database Centre, CCDC no. 130257 for compound 3
and 130258 for compound 4. Copies of this information
may be obtained free of charge from: The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
[Fax: +44-1223-336-033 or e-mail: deposit@ccdc.cam.
ac.uk or http://www.ccdc.cam.ac.uk].
2
References
(C(CH3)3), 67.2 (q, JFC=3.0 Hz, ZrC(CH3)3), 115.2
2
3
(d, JFC=21.7 Hz, C3 of 2-FC6H4), 120.0 (d, JFC=7.9
Hz, C4 of 2-FC6H4), 122.0, 125.9 (C5,6 of 2-FC6H4),
140.6 (d, 2JFC=13.8 Hz, C1 of 2-FC6H4), 158.7 (d,
[1] (a) L.H. Gade, N. Mahr, J. Chem. Soc. Dalton Trans. (1993) 489.
(b) L.H. Gade, C. Becker, J.W. Lauher, Inorg. Chem. 32 (1993)
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1JFC=229.2 Hz, C2 of 2-FC6H4). {1H}19F-NMR
.
(C6D6, 295 K): l −123.5. {1H}29Si-NMR (C6D6, 295
K): l 3.2. C29H40F3N3Si3Zr (663.13): Anal. Calc. C,
52.53; H, 6.08; N, 6.34. Found C, 52.31; H, 5.99; N,
6.30.
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3.6. X-ray crystallographic studies of 3 and 4
Data were collected using an Enraf–Nonius CAD4
diffractometer at a temperature of 153(2) K (3) and
193(2) K (4) with oil-coated shock-cooled crystals [13]
mounted on the top of a glass pin under nitrogen.
Crystal data and experimental details for the crystals of
3 and 4 are given in Table 3. All data for the two
structures were corrected for absorption (C-scans).
Structure 3 was solved by direct methods, structure 4
by Patterson methods (SHELXS-97) and both were
refined on F2 (SHELXL-97) [14]. In the case of 3, disor-
der of all diethylether molecules was found. In the final
cycles of refinement, all non-hydrogen atoms of 3 and 4
were assigned anisotropic displacement parameters. Hy-
drogen atoms were included in idealized positions rid-
ing on the parent atoms and were assigned isotropic
displacement parameters of 1.2Ueq (ꢁCH, CH, CH2)
and 1.5Ueq (CH3) of the parent atom.
The structure of the chlorozirconium–lithum chlo-
[9] B. Schubert, E. Weiss, Angew. Chem. Int. Ed. Engl. 22 (1983) 496.
[10] D. Barr, W. Clegg, R.E. Mulvey, R. Snaith, J. Chem. Soc. Chem.
Commun. (1984) 79.
[11] D. Seebach, Angew. Chem. Int. Ed. Engl. 27 (1988) 1624.
[12] R. Amstutz, W.B. Schweizer, D. Seebach, J. Dunitz, Helv. Chim.
Acta 64 (1981) 2617.
[13] T. Kottke, D. Stalke, J. Appl. Crystallogr. 26 (1993) 615.
[14] (a) G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990) 467. (b)
G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refin-
ement, Universita¨t Go¨ttingen, 1997.
ride
complex
[HC{SiMe2N(4-CH3C6H4)}3Zr{Cl4-
(LiꢀOEt2)3}] (3) was refined (SHELXL-97) by application
of a rigid-bond restraint to Uij values (DELU) with low
ESDs and assumption of ‘similar’ Uij values (SIMU)
with large ESDs due to the high disorder of all four
diethylether molecules. For one carbon atom (C60)
approximation of isotropic behaviour of its Uij values
(ISOR) with large ESDs was used.