Novel synthesis of zirconocene difluoride and alkyl monofluoride complexes

Article abstract of DOI:10.1021/om049745u

Starting from zirconocene bis(trimethylsilyl)acetylene complexes Cp′₂Zr(L)(η²btmsa) via the 2-vinylpyridine complexes Cp′₂Zr(2-vipy) a novel synthetic method for zirconocene difluoride and alkyl monofluoride complexes was elaborated. Examples with selected different ligand systems Cp′₂ [Cp₂ = bis(η⁵-cyclopentadienyl); ebthi = 1,2-ethylene-1,1′- bis(η⁵-tetrahydroindenyl); (thi)₂ = bis(η⁵-tetrahydroindenyl); Me₂Si(η⁵- C₅H₄)₂ = dimethylsilylbis-(η⁵- cyclopentadienyl); (i)₂ = bis(η⁵-indenyl); ebi = 1,2-ethylene-1,1′-bis(η⁵-indenyl); and Me ₂Si(η⁵-C₉H₁₀)₂ = dimethylsilyl-1,1′-bis(η⁵-tetrahydroindenyl)] were synthesized. In the series of these investigations new complexes (i) ₂Zr(THF)(η²-btmsa) (1), rac-(ebi)Zr(THF) (η²-btmsa) (2), (thi)₂Zr(2-vipy) (3), Me ₂Si(η⁵-C₅H₄)₂Zr(2- vipy) (4), (i)₂Zr(2-vipy) (5), and rac-(ebthi)-Zr(2-Ph-vipy) (6) were prepared as starting materials. Different methods for preparation of the zirconocene difluorides rac-(ebthi)ZrF₂ (7), (thi) ₂ZrF₂ (8), Me₄C₂(η⁵- C₅H₄)₂ZrF₂ (9), and Me ₂Si(η⁵-C₉H₁₀) ₂ZrF₂ (10) and the monofluorides Cp₂Zr(F) (CH₂CH₂-2-Py) (11), rac-(ebthi)-Zr(F)(CH ₂CH₂-2-Py) (12), (thi)₂Zr(F)(CH ₂CH₂-2-py) (13), Me₂Si(η⁵-C ₅H₄)₂Zr(F)(CH₂CH₂-2-py) (14), and Me₂Si(η⁵-C₉H₁₀) ₂ZrF(Me) (15) are reported and compared. The molecular structures of the bis-η⁵-tetrahydroindenyl complexes 3, 8, and 13 were confirmed by X-ray crystal structure analysis.

Full text of DOI:10.1021/om049745u

Organometallics 2004, 23, 3819-3825
3819
Novel Syn th esis of Zir con ocen e Diflu or id e a n d Alk yl
Mon oflu or id e Com p lexes
Anke Spannenberg,*,† Perdita Arndt,† Wolfgang Baumann,†
Vladimir V. Burlakov,† Uwe Rosenthal,*,† Sigurd Becke,‡ and Thomas Weiss‡
Leibniz-Institut fu¨r Organische Katalyse an der Universita¨t Rostock e. V.,
Buchbinderstrasse 5-6, D-18055 Rostock, Germany, and Bayer AG, Bayer Polymers,
BPO-IIS-INN-SYR-SE, Q 18, D-51368 Leverkusen, Germany
Received April 8, 2004
Starting from zirconocene bis(trimethylsilyl)acetylene complexes Cp′2Zr(L)(η2-btmsa) via
the 2-vinylpyridine complexes Cp′2Zr(2-vipy) a novel synthetic method for zirconocene
difluoride and alkyl monofluoride complexes was elaborated. Examples with selected different
ligand systems Cp′2 [Cp2 ) bis(η5-cyclopentadienyl); ebthi ) 1,2-ethylene-1,1′-bis(η5-
tetrahydroindenyl); (thi)2 ) bis(η5-tetrahydroindenyl); Me2Si(η5-C5H4)2 ) dimethylsilylbis-
(η5-cyclopentadienyl); (i)2 ) bis(η5-indenyl); ebi ) 1,2-ethylene-1,1′-bis(η5-indenyl); and
Me2Si(η5-C9H10)2 ) dimethylsilyl-1,1′-bis(η5-tetrahydroindenyl)] were synthesized. In the
series of these investigations new complexes (i)2Zr(THF)(η2-btmsa) (1), rac-(ebi)Zr(THF)(η2-
btmsa) (2), (thi)2Zr(2-vipy) (3), Me2Si(η5-C5H4)2Zr(2-vipy) (4), (i)2Zr(2-vipy) (5), and rac-(ebthi)-
Zr(2-Ph-vipy) (6) were prepared as starting materials. Different methods for preparation of
the zirconocene difluorides rac-(ebthi)ZrF2 (7), (thi)2ZrF2 (8), Me4C2(η5-C5H4)2ZrF2 (9), and
Me2Si(η5-C9H10)2ZrF2 (10) and the monofluorides Cp2Zr(F)(CH2CH2-2-Py) (11), rac-(ebthi)-
Zr(F)(CH2CH2-2-py) (12), (thi)2Zr(F)(CH2CH2-2-py) (13), Me2Si(η5-C5H4)2Zr(F)(CH2CH2-2-py)
(14), and Me2Si(η5-C9H10)2ZrF(Me) (15) are reported and compared. The molecular structures
of the bis-η5-tetrahydroindenyl complexes 3, 8, and 13 were confirmed by X-ray crystal
structure analysis.
In tr od u ction
ate counterions were used.2c-e Most compounds devel-
oped for this purpose are based on perfluorophenyl-
boron compounds, e.g., tris(pentafluorophenyl)borane,
B(C6F5)3.2f-i
For economic reasons, there is a great interest in
finding cheaper catalyst systems. This could be achieved
by tuning the metallocene ligand and/or finding a
cheaper cocatalyst.2j Isobutylalumoxane2k,l as well as
hydroxy-isobutylalumoxane2j have been published re-
cently as alternative cocatalysts in metallocene activa-
tion.
The metallocene-type Ziegler-Natta catalysts fre-
quently used in catalytic olefin polymerization typically
consist of a complex of two cyclopentadienyl anion-based
ligands with a metal cation.1 This metallocene is not
able to polymerize olefins; it needs activation.1,2 Methyl-
aluminoxane is the activator generally used in industry,
although there is no detailed knowledge about its
specific role in the polymerization processes. As an
alternative to methylalumoxane, noncoordinating bor-
Recently we claimed that zirconocene difluoride and
zirconocene monofluoride alkyl complexes, among them
rac-(ebthi)ZrF2 (7),4c are active catalysts for ethylene
* Corresponding author. E-mail: uwe.rosenthal@ifok.uni-rostock-
de.
† Leibniz-Institut fu¨r Organische Katalyse an der Universita¨t
Rostock e. V.
i
polymerization with Bu3Al as the sole activating co-
‡ Bayer AG.
catalyst.5 In contrast to fluorine-containing 7, the
dichloride rac-(ebthi)ZrCl2 was found to be totally inac-
tive under comparable reaction conditions!
(1) (a) Brintzinger, H. H.; Fischer, D.; Mu¨lhaupt, R.; Rieger, B.;
Waymouth, R. Angew. Chem. 1995, 107, 1255; Angew. Chem., Int. Ed.
Engl. 1995, 34, 1143, and references therein. (b) J aniak, C. In
Metallocenes; Togni, A., Halterman, R. L., Eds.; Wiley-VCH: New York,
1998; Vol. 2, p 547. (c) Tullo, A. H. Chem. Eng. News 2001, 79, 35.
(2) (a) Sinn, H. Macromol. Symp. 1995, 97, 27. (b) Kaminsky, W.
Angew. Makromol. Chem. 1994, 223, 201. (c) J ordan, R. F.; Bajgur, C.
S.; Willet, R.; Scott, B. J . Am. Chem. Soc. 1986, 108, 7410. (d)
Bochmann, M.; Wilson, L. M. J . Chem. Soc., Chem. Commun. 1986,
1610. (e) Hlatky, G. G.; Turner, H. W.; Eckmann, R. J . Am. Chem.
Soc. 1989, 111, 2728. (f) Yang, X.; Stern, C. L.; Marks, T. J . J . Am.
Chem. Soc. 1991, 113, 3623. (g) Ewen, J . A.; Edler, M. J . CA-A 2 1991,
027, 145. (h) Piers, W. E. Chem. Eur. J . 1998, 13. (i) Erker, G. Acc.
Chem. Res. 2001, 34, 309. (j) Tullo, A. H. Chem. Eng. News 2001, 79,
38. (k) Barron, A. R. Organometallics 1995, 14, 3581. (l) Watanabe,
M.; McMahon, C. N.; Harlan, C. J .; Barron, A. R. Organometallics 2001,
20, 460. (m) Marks, T. J . Chem. Rev. 2000, 100, 1391.
These results and the extraordinary effects of the
fluoride3,6 prompted us to investigate zirconocene fluoro
complexes. From our point of view the activation of
zirconocene catalysts depends both on the nature of the
(4) (a) Wild, F. W. R. P.; Zsolnai, L.; Huttner, G.; Brintzinger, H. H.
J . Organomet. Chem. 1982, 232, 233. (b) Lefeber, C.; Baumann, W.;
Tillack, A.; Kempe, R.; Go¨rls, H.; Rosenthal, U. Organometallics 1996,
15, 3486. (c) Thomas, D.; Baumann, W.; Spannenberg, A.; Kempe, R.;
Rosenthal, U. Organometallics 1998, 17, 2096. (d) Mansel, S.; Thomas,
D.; Lefeber, C.; Heller, D.; Kempe, R.; Baumann, W.; Rosenthal, U.
Organometallics 1997, 16, 2886.
(5) (a) Becke, S.; Rosenthal, U. (Bayer AG) DE 199 32 409 A1
(18.01.2001). (b) Becke, S.; Rosenthal, U. (Bayer AG) US 6,303,718 B1
(16.10.2001). (c) Becke, S.; Rosenthal, U.; Arndt, P.; Baumann, W.;
Spannenberg, A. (Bayer AG) DE 101 10 227 A1 (05.09.2002).
(3) (a) Longo, P.; Oliva, L.; Grassi, A.; Pellecchia, C. Makromol.
Chem. 1989, 190, 2357. (b) Pedeutour, J . N.; Cramail, H.; Deffieux, A.
J . Mol. Catal. A: Chem. 2001, 174, 81. (c) Schwecke, C.; Kaminsky,
W. Macromol. Rapid Commun. 2001, 22, 508. (d) Qian, Y.; Zhang, H.;
Qian, X.; Huang, J .; Shen, C. J . Mol. Catal. A: Chem. 2003, 192, 25.
10.1021/om049745u CCC: $27.50 © 2004 American Chemical Society
Publication on Web 07/08/2004

3820 Organometallics, Vol. 23, No. 16, 2004
Spannenberg et al.
Sch em e 1
Sch em e 2
leaving ligand when forming the active species and on
the character and stability of the resulting counterpart
(anion). For this purpose we elaborated synthetic meth-
ods to obtain zirconocene difluoride and alkyl mono-
fluoride complexes as metallocene components.
Sch em e 3
Resu lts a n d Discu ssion
P r ep a r a t ion of t h e St a r t in g Ma t er ia ls. Zir -
con ocen e Com p lexes of Bis(tr im eth ylsilyl)a cety-
len e a n d 2-Vin ylp yr id in e. Both groups of complexes
with bis(trimethylsilyl)acetylene (btmsa) and 2-vinyl-
pyridine (2-vipy) were known before. In addition to
the already known alkyne complexes Cp′2Zr(L)(η2-
btmsa)4b,7a-c the new complexes with Cp′2 ) (i)2 (1) and
Cp′2 ) rac-(ebi) (2) with L ) THF were prepared
following the same procedure of reduction of the corre-
sponding dichlorides with magnesium in the presence
of btmsa. These complexes were used as starting
materials for subsequent investigations (Scheme 1).8
Zirconocene complexes with 2-vinylpyridine Cp′2Zr-
(2-vipy) (Cp′2 ) Cp2, ebthi) are already known.4c The
new complexes (thi)2Zr(2-vipy) (3), Me2Si(η5-C5H4)2Zr-
(2-vipy) (4), and (i)2Zr(2-vipy) (5) were prepared follow-
ing the same method of substitution of btmsa by 2-vipy
(Scheme 1). This procedure did not work to prepare the
corresponding rac-(ebi)Zr(2-vipy) because intractable
mixtures of complexes were formed.
Sch em e 4
Zir con ocen e Diflu or id es. There are many pub-
lished methods for the preparation of metallocene di-
fluorides, mostly based on exchange reactions with Me3-
SnF as a versatile reagent.10 We prepared a number of
such complexes like rac-(ebthi)ZrF2 (7), (thi)2ZrF2 (8),
and Me4C2(η5-C5H4)2ZrF2 (9) by using of 3 equiv of Me3-
SnF for 7 and 2.1 equiv of Me3SnF in the case of 8 and
9, both in dichloromethane solution. Alternatively, we
used ZnF2 as a cheaper fluorinating agent in acetone
to obtain rac-(ebthi)ZrF2 (7) (Scheme 3).
The complex rac-(ebthi)Zr(2-Ph-vipy) (6) was prepared
directly by reduction starting from rac-(ebthi)ZrCl2, 2-(2-
phenylvinyl)pyridine, and lithium in THF at -40 °C
(Scheme 2),9 but this procedure failed to produce rac-
(ebi)Zr(2-vipy) from rac-(ebi)ZrCl2 and 2-vinylpyridine,
giving again a mixture of complexes.
(6) (a) Mezzetti, A.; Becker, C. Helv. Chim. Acta 2002, 85, 2686. (b)
Pagenkopf, B. L.; Carreira, M. Chem. Eur. J . 1999, 5, 3437. (b)
Pagenkopf, B. L.; Carreira, M. Tetrahedron Lett. 1998, 39, 9593. (c)
Fagnou, K.; Lautens, M. Angew. Chem. 2002, 114, 27; Angew. Chem.,
Int. Ed. 2002, 41, 26. (d) Verdaguer, X.; Lange, U. E. W.; Reding, M.
T.; Buchwald, S. L. J . Am. Chem. Soc. 1996, 118, 6784. (e) Dorta, R.;
Egli, P.; Zu¨rcher, F.; Togni, A. J . Am. Chem. Soc. 1997, 119, 10857. (f)
Togni, A.; Burckhardt, U.; Gramlich, V.; Pregosin, P. S.; Salzmann, R.
J . Am. Chem. Soc. 1996, 118, 1031. (g) Kru¨ger, J .; Carreira, E. M. J .
Am. Chem. Soc. 1998, 120, 837.
(7) (a) Rosenthal, U.; Ohff, A.; Michalik, M.; Go¨rls, H.; Burlakov, V.
V.; Shur, V. B. Angew. Chem. 1993, 105, 1228; Angew. Chem., Int. Ed.
Engl. 1993, 32, 1193. (b) Peulecke, N.; Baumann, W.; Kempe, R.;
Burlakov, V. V.; Rosenthal, U. Eur. J . Inorg. Chem. 1998, 419. (c)
Peulecke, N.; Lefeber, C.; Ohff, A.; Baumann, W.; Tillack, A.; Kempe,
R.; Burlakov, V. V.; Rosenthal, U. Chem. Ber. 1996, 129, 959.
(8) (a) Ohff, A.; Pulst, S.; Peulecke, N.; Arndt, P.; Burlakov, V. V.;
Rosenthal, U. Synlett 1996, 111. (b) Rosenthal, U.; Pellny, P.-M.;
Kirchbauer, F. G.; Burlakov, V. V. Acc. Chem. Res. 2000, 33, 119. (c)
Rosenthal, U.; Burlakov, V. V. Organometallic Chemistry of Titanocene
and Zirconocene Complexes with Bis(trimethylsilyl)acetylene as the
Basis for Applications in Organic Synthesis. In Titanium and Zirco-
nium in Organic Synthesis; Marek, I., Ed.; Wiley-VCH: Weinheim,
2002; p 355. (d) Rosenthal, U.; Burlakov, V. V.; Arndt, P.; Baumann,
W.; Spannenberg, A. J . Organomet. Chem. 2003, 670, 84. (e) Rosenthal,
U.; Burlakov, V. V.; Arndt, P.; Baumann, W.; Spannenberg, A.
Organometallics 2003, 22, 884.
Another method for the preparation of metallocene
difluorides is the acidolysis reaction starting from
suitable starting materials4c (Scheme 4).
For rac-(ebthi)Zr(2-vipy) this was proven first by
reaction with HBF4 etherate to obtain rac-(ebthi)ZrF2
(7, poorly reproducible).4c Better suited is NEt3‚3HF as
reagent for this reaction,11 which gives the difluoride 7
starting from rac-(ebthi)Zr(2-vipy) or from rac-(ebthi)-
ZrMe2. Also NH4BF4 can be used to produce the difluo-
ride Me2Si(η5-C9H10)2ZrF2 (10) from Me2Si(η5-C9H10)2-
ZrMe2 (Scheme 5).
Zir con ocen e Alk yl Mon oflu or id es. Regarding the
metallocene alkyl monofluorides, it was impossible to
obtain the monofluoride rac-(ebthi)Zr(F)(CH2CH2-2-Py)
(12) starting from rac-(ebthi)Zr(2-vipy) by using HBF4
etherate because only rac-(ebthi)ZrF2 (7) was obtained.4c
(10) Murphy, E. F.; Murugavel, R.; Roesky, H. W. Chem. Rev. 1997,
97, 3425.
(9) We thank Dr. Kahlert, Bayer AG, for information concerning this
synthetic procedure.
(11) We thank Dr. Windisch, Bayer AG, for a hint concerning this
excellent reagent.

Zirconocene Difluoride Complexes
Organometallics, Vol. 23, No. 16, 2004 3821
Sch em e 5
The reaction of rac-(ebthi)Zr(2-vipy) with NH4F often
gave mixtures of the monofluoride 12 and the difluoride
7. A suitable reagent to prepare such monofluorides is
NEt3‚3HF,11 provided one takes great care of the exact
stoichiometry. The reaction of Cp2Zr(2-vipy) with
NEt3‚3HF gives Cp2Zr(F)(CH2CH2-2-Py) (11). In the
same manner the complexes rac-(ebthi)Zr(F)(CH2CH2-
2-py) (12), (thi)2Zr(F)(CH2CH2-2-py) (13), and Me2Si(η5-
C5H4)2Zr(F)(CH2CH2-2-py) (14) were formed (Scheme 4).
This reagent also works well with zirconocene dimethyl
complexes such as Me2Si(η5-C9H10)2ZrMe2 to give
Me2Si(η5-C9H10)2ZrF(Me) (15) (Scheme 5).
F igu r e 1. Molecular structure of complex 3 in the crystal.
Hydrogen atoms are omitted for clarity. The thermal
ellipsoids correspond to 30% probability. Selected bond
lengths [Å] and angles [deg]: Zr-C13 2.282(4), Zr-C12
2.604(5), Zr-C11 2.687(4), Zr-N 2.163(3), C12-C13 1.442-
(8), C11-C12 1.379(7), N-C11 1.393(6), N-C22 1.364(5),
C22-C23 1.366(6), C23-C24 1.413(9), C24-C25 1.340(9),
C11-C25 1.424(7); N-Zr-C13 82.3(2); X1a-Zr-X1b 127.8
(X1a, X1b are centroids of C1-C5 and C6-C10, respec-
tively).
It is worth mentioning that all these methods failed
to synthesize the corresponding complexes with unsat-
urated substituents at the Cp ring. There are some hints
from NMR spectroscopic investigations of the compli-
cated reaction mixtures on a modification of the unsat-
urated groups.
NMR In vestiga tion s. As described earlier, the co-
ordination of the 2-vinylpyridine to the zirconocene core
changes the electronic structure of the ligand so that it
is described best as a coordinated monoazadiene which
becomes a metallaazacyclopentene.4c The aromaticity of
the pyridine subunit is reduced, and there is a certain
discrimination of bond orders within the ring (partially
localized double bonds, evidenced by clearly different
3
coupling constants J H,H across “single” (C23-C24 in 3,
F igu r e 2. Molecular structure of complex 13 in the crystal.
Hydrogen atoms are omitted for clarity. The thermal
ellipsoids correspond to 30% probability. Selected bond
lengths [Å]: Zr-C15 2.377(3), Zr-N 2.497(3), Zr-F 2.025-
(2), C15-C16 1.524(5), C16-C17 1.489(5), N-C17 1.360-
(4), N-C21 1.349(4), C17-C18 1.388(5), C18-C19 1.372(7),
C19-C20 1.373(7), C20-C21 1.374(5).
see Figure 1) and “double” (C24-C25 in 3) bonds. Upon
formation of the complexes 11-14 (reaction with HF
derivatives), this kind of interaction is released and
NMR spectroscopic properties of an undisturbed pyri-
1
dine system are found again. H and 13C NMR spectra
of the monofluoro complexes 11-14 with a 2-(2-pyridyl)-
ethyl group show various scalar couplings to the fluorine
atoms, most prominent for the CH group adjacent to
nitrogen (C21 in Figure 2). In the solid state, the
nitrogen atom is directed toward the metal center; a
close proximity to the fluorine results from this orienta-
tion. σ-Bonding interactions between halogen, particu-
larly fluorine, and pyridine nitrogen atoms are known12
and give rise to a low-field shift of the ortho protons (δ
X-r a y Cr ysta l Str u ctu r es. Representative examples
of described complexes were investigated by X-ray
crystal structure analysis: starting 2-vinylpyridine
complex 3, the monofluoride 13, and the difluoride 8.
The crystallographic data are listed in Table 1, and the
molecular structures are shown in Figures1-3.
All complexes consist of a typical bent zirconocene in
a monomeric structure.
3
9.3 ppm) together with a coupling J H,F of 16 Hz. The
A comparison of 3 and 13 seems worth doing; both
molecules have a C-C-2-py subunit. Selected data are
presented in Table 2.
chemical shifts observed for 11-14 are very similar to
each other. The coupling constants are smaller (6-7
Hz), so it is not clear whether they do result from such
a special bonding situation or wheter they are transmit-
ted “through space”, as commonly observed with the
fluorine nucleus. However, the chemical shift of fluorine
in these complexes should be noted, which is about 100
ppm shifted to lower frequency compared to that of the
similar methyl-fluoro complex 15.
The starting point in the discussion of the compared
examples is the 2-vinylpyridine complex 3. The angle
between the plane defined by X1a, X1b, and Zr (X1a and
X1b are the centroids of C1-C5 and C6-C10, respec-
tively) and the plane defined by Zr, N, and C13 is 88.0°.
As described before in similar complexes, the 2-vinylpy-
ridine gives by complexation a five-membered zircona-
cycle with a fused pyridine ring. With a “localization”
of the double bonds within the pyridine ring a 1-zircona-
2-azacyclopent-3-ene (1-monoazadiene) is formed. The
(12) (a) Meinert, H. Z. Chem. 1965, 5, 64. (b) Umemoto, T.; Tomita,
K. Tetrahedron Lett. 1986, 27, 3271. (c) Umemoto, T.; Tomizawa, G.
J . Org. Chem. 1989, 54, 1726.

3822 Organometallics, Vol. 23, No. 16, 2004
Spannenberg et al.
alternating bond distances in the pyridine ring support
the bonding description with dearomatization as a
2-dihydropyridin-2-ylidene in conjugation with the un-
saturated zirconacycle. The description as a 1-zircona-
2-azacyclopent-3-ene rather than a η4-1-azadiene com-
plex or an olefin complex stabilized by pyridine N atom
coordination is favored.
The five-membered zirconacycle with a fused pyridine
ring that is present in the structure of 13 differs clearly
from the above-mentioned system in 3. There is no
“localization” of the double bonds within the pyridine
ring, and a N-ligand-stabilized σ-alkyl complex is formed.
The Zr-CR and CR-Câ are single σ-bonds, both longer
than found in 3. The Zr-N bond length is in the typical
range of pyridine-N coordination and not of zirconium
amides. There is no bond from Zr to the Câ and Câ′
atoms. The bonding description as an σ-alkyl complex
stabilized by pyridine N atom coordination is favored.
Addionally, there is a fluoride coordinated at the metal
center. The Zr-F bond length is longer than found in
the difluoride 8. The reason for this could be a F-N
interaction (2.662 Å; N-F-Zr 62.7°) or H21-F interac-
tion (2.089 Å), cf. NMR Investigations.
F igu r e 3. Molecular structure of complex 8 in the crystal.
Hydrogen atoms are omitted for clarity. The thermal
ellipsoids correspond to 30% probability. Selected bond
lengths [Å] and angles [deg]: F1-Zr 1.946(2), F2-Zr 1.974-
(2); F1-Zr-F2 98.66(8), X1a-Zr-X1b 132.3 (X1a, X1b are
centroids of C1, C2, C3, C8, C9 and C10, C11, C12, C13,
C18, respectively).
Ta ble 1. Cr ysta llogr a p h ic Da ta
3
8
13
cryst syst
space group
a [Å]
b [Å]
c [Å]
orthorhombic monoclinic orthorhombic
In the structure of (thi)2ZrF2 (8) the angle between
the planes defined by X1a, X1b, and Zr (X1a and X1b
are centroids of C1, C2, C3, C8, C9 and C10, C11, C12,
C13, C18, respectively) and Zr, F1, and F2 is 89.1°.
P21212
P21/n
Pbca
8.708(2)
27.547(6)
8.547(2)
7.002(1)
18.910(4)
11.667(2)
96.12(3)
1536.0(5)
4
8.753(2)
18.251(4)
25.778(5)
â [deg]
V [Å3]
2050.2(8)
4
4118.1(15)
8
Z
Con clu sion
density [g‚cm-3
]
1.408
0.545
293
1.590
0.728
200
1.467
0.553
200
µ(Mo KR) [mm-1
T [K]
]
Zirconocene difluorides and zirconocene alkyl mono-
fluorides can be prepared by a route starting from the
bis(trimethylsilyl)acetylene complexes via the 2-vinylpy-
ridine complexes and a subsequent reaction with flu-
orinating reagents. HBF4 etherate, NH4BF4, and NEt3‚
3HF are well suited to produce the difluorides, whereas
the only suitable reagent to prepare monofluorides is
NEt3‚3HF. All these methods failed to synthesize the
corresponding complexes with unsaturated substituents
at the Cp ring.
no. of reflns (measd) 10864
no. of reflns (indep) 3206
3987
2046
1783
190
0.025
0.059
11567
3307
2461
278
0.034
0.085
no. of reflns (obsd)
no. of params
R1 (I>2σ(I))
2779
252
0.027
0.060
wR2 (all data)
Ta ble 2. Selected Da ta of Com p lexes w ith th e
C-C-2-p y Su bu n it in th e Molecu le
3
13
Zr-CR
2.282(4)
2.604(5)
2.687(4)
2.163(3)
1.442(8)
1.379(7)
2.377(3)
no bond
no bond
2.497(3)
1.524(5)
1.489(5)
Zr-Câ
Exp er im en ta l Section
Zr-Câ′(py-ring)
Zr-N
Gen er a l P r oced u r es. All operations were carried out
under argon with standard Schlenk techniques. Prior to use
nonhalogenated solvents were freshly distilled from sodium
tetraethylaluminate and stored under argon.
The following spectrometers were used: mass spectra, AMD
402; NMR spectra, Bruker ARX 400 and AC 250 (19F).
Chemical shifts (1H, 13C, 29Si) are given relative to SiMe4 and
are referenced to signals of the used solvents: benzene-d6 (δH
) 7.16, δC ) 128.0), toluene-d8 (δH ) 2.03, δC ) 20.4),
CR-Câ
Câ-(Câ′-py-ring)
pyridine
N-Câ′(Zr-ring)
N-C(py-ring)
1.393(6)
1.364(5)
1.360(4)
1.349(4)
Zr-CR distance is typical for Zr-C σ-bonds, and the
Zr-N bond length is in the typical range of zirconium
amides and not of pyridine-N coordination. The large
distances from Zr to the internal C atoms indicate a
weak Zr-π(CdC) interaction. The σ2,π-interaction adopts
the typical “envelope” structure with an angle of 53.9°
at the N-C13 axis (Zr, N, C13/C11, C12, C13, N). The
different bond lengths in the five-membered ring, the
long CR-Câ and the short Câ-(Câ′-py-ring) bond, are
analogous to the s-cis-diene complexes. Regarding the
difference between the distances in N-Câ′(Zr-ring)/N-
C(py-ring) in 3, there is no such large difference found
in the other examples of previously described complexes
of this type, Cp2Zr(2-vipy) and rac-(ebthi)Zr(2-vipy) (first
∆d ) 0.046, second ∆d ) 0.041 Å). Nevertheless the
tetrahydrofuran-d8 (δH ) 1.73, δC ) 25.2), chloroform-d (δH
)
7.27, δC ) 77.0); chemical shifts (19F) are given relative to
CFCl3. The spectra were assigned with the help of DEPT and
shift correlation experiments. Melting points: sealed capil-
laries, Bu¨chi 535 apparatus. Elemental analyses: Leco CHNS-
932 elemental analyzer.
Alk yn e Com p lexes. The complexes (thi)2Zr(THF)(η2-
btmsa)7b and Me2Si(η5-C5H4)2Zr(py)(η2-btmsa)7c were prepared
according to the published methods.
(i)2Zr (THF)(η2-btm sa) (1). Bis(trimethylsilyl)acetylene (306
µL, 1.35 mmol) was added to a suspension of (i)2ZrCl2 (531
mg, 1.35 mmol) and magnesium (32 mg, 1.35 mmol) in 25 mL
of THF. The resulting deep brown mixture was stirred for
4 h at ambient temperature. After evaporation of the THF,

Zirconocene Difluoride Complexes
Organometallics, Vol. 23, No. 16, 2004 3823
but not totally to dryness, the residue was dissolved in a 1:3
mixture of THF/n-hexane. After filtration deep red crystals
were formed upon cooling at -40 °C within 48 h. The crystals
were separated to give 309 mg (55%) of 1, mp 106-110 °C.
Anal. Calcd for C30H40OSi2Zr (564.04): C, 63.88; H, 7.15.
within 48 h. The crystals were separated to give 171 mg (56%)
of 5, mp 182 °C. Anal. Calcd for C25H21NZr (426.67): C, 70.38;
1
H, 4.96; N, 3.28. Found: C, 69.96; H, 5.12; N, 3.08. H NMR
(toluene-d8): δ -3.63, (t, J ) 9.7 Hz, 1H, CH2-vipy), 1.80 (t, J
) 9.3 Hz, 1H, CH2-vipy), 3.92 (t, J ) 9.8 Hz, 1H, CH-vipy),
5.47, 6.23, 6.33, 7.30 (4 m, 4H, CH-vipy), 5.05, 5.06, 5.19, 5.74,
5.87, 6.17 (6H, Cp-indenyl), 6.33, 6.67, 6.76, 6.83, 6.85, 6.97,
7.04 (8H, C6-ring-indenyl). 13C{1H} NMR (toluene-d8): δ 60.6
(CH2-vipy), 88.9 (CH-vipy), 99.5, 97.9, 92.0, 92.2, 93.7, 111.8
(CH-Cp-indenyl), 128.7, 123.1, 123.5, 122.2, 124.2, 122.8, 123.4,
123.1 (C6-ring-indenyl), 118.5, 118.7, 122.0, 122.9 (Cq-indenyl),
123.0, 122.0, 103.8, 146.0 (CH, py), 137.0 (Cq-py). MS (70 eV)
m/z: 425 [(i)2Zr(vipy)]+.
1
Found: C, 63.61; H, 6.87. H NMR (THF-d8): δ 0.11 (s, 18H,
SiMe3), 1.78, 3.62 (2 m, 4H each, THF), 5.62, (d, 4H, 1-H and
3-H), 6.08 (t, 2H, 2-H), 6.84, 7.17 (2 m, 4H each, 4-, 5-, 6-, 7-H).
13C{1H} NMR (THF-d8): δ 2.6 (SiMe3), 26.3, 68.1 (CH2-THF),
90.8, 117.3, 122.9, 124.3 (CH-indenyl), 127.4, 134.8 (Cq-
indenyl), tC-Si not observed due to molecular dynamics.7 MS
(70 eV) m/z: 490 [(i)2Zr(Me3SiC2SiMe3)]+.
r a c-(ebi)Zr (THF )(η2-btm sa ) (2). The same procedure as
described for 1, but starting from (ebi)2ZrCl2 (639 mg, 1.53
mmol), magnesium (37 mg), and bis(trimethylsilyl)acetylene
(346 µL, 1.53 mmol) gives deep red needles (269 mg, 46%) of
2, mp 98-106 °C. Anal. Calcd for C32H42OSi2Zr (590.08): C,
r a c-(ebth i)Zr (2-P h -2-vip y) (6). rac-(ebthi)ZrCl2 (806 mg,
1.89 mmol), 2-(2-phenylvinyl)pyridine (342 mg, 1.89 mmol),
and lithium (26 mg, 3.78 mmol) were suspended at -40 °C in
20 mL of THF. The reaction mixture was stirred for a further
24 h at -40 °C. The color of the solution turned to dark red/
red-brown. After filtration and crystallization at -30 °C
crystals of 6 were obtained (578 mg, 57%), mp 248 °C. Anal.
Calcd for C33H35NZr (536.87): C, 73.83; H, 6.57; N, 2.61.
Found: C, 73.39; H, 6.43; N, 2.60. 1H NMR (benzene-d6): δ
1
65.14; H, 7.17. Found: C, 64.99; H, 7.07. H NMR (THF-d8):
δ 0.11 (s, 18H, SiMe3), 1.78, 3.62 (2 m, 4H each, THF), 3.26,
3.55 (2 m, 2H each, CH2), 5.47, 6.60 (2 d, 2H each, 2-H and
3-H), 6.79 (m, 4H, 5-H and 6-H), 6.97, 7.71 (2 d, 2H each, 4-H
and 7-H). 13C{1H} NMR (THF-d8): δ 4.1 (SiMe3), 26.3, 68.1
(CH2 THF), 30.5 (CH2), 91.6, 111.2, 120.4, 122.1, 124.3, 125.3
(CH-indenyl), 117.6, 121.3 (Cq-indenyl), further C not observed
due to molecular dynamics.7 MS (70 eV) m/z: 517 [(ebi)Zr-
(Me3SiC2SiMe3)]+.
3
-0.33 (d, 1H, J ) 8.5 Hz, Zr-R-CH); 4.81 (d, 1H, CH ebthi);
4.94 (d, 1H, 3J ) 8.5 Hz, Zr-â-CH); 4.97 (d, 1H, CH ebthi);
3
5.53 (d, 1H, CH ebthi); 5.56 (d, 1H, CH ebthi); 5.61 (t, 1H, J
3
) 6 Hz, py-5); 6.29 (dd, 1H, J ) 6 and 9 Hz, Py-4); 6.62 (d,
1H, 3J ) 9 Hz, Py-3); 7.07 (t, 1H, p-Ph); 7.24 (d, 2H, o-Ph);
2-Vin ylp yr id in e Com p lexes. The complexes Cp2Zr(2-vipy)
and rac-(ebthi)Zr(2-vipy) were prepared as described before.4c
The following complexes were prepared in analogy with the
published methods.
3
7.32 (t, 2H, m-Ph); 7.48 (d, 1H, J ) 6 Hz, Py-6); CH2 signals
not analyzed. 13C NMR (benzene-d6): δ 23.3, 23.4, 23.4, 24.2,
24.3, 24.6, 24.9, 25.4, 28.8, 29.9 (10 × CH2); 75.5 (Zr-R-CH);
91.6 (Zr-â-CH); 100.9, 101.2, 102.5, 105.3 (4 × CH ebthi); 116.2,
116.7, 119.6, 121.1, 124.3, 125.0 (6 × C ebthi); 108.4 (Py-5);
125.9 (Py-3); 127.2 (Py-4); 137.9 (Py-2); 146.0 (Py-6). MS (70
eV) m/z: 535 [(ebthi)Zr(2-Ph-2-vipy)]+.
(th i)2Zr (2-vip y) (3). 2-Vinylpyridine (57.5 µL, 0.53 mmol)
was added by a syringe to a solution of (thi)2Zr(THF)(η2-
btmsa)7b (303 mg, 0.53 mmol) in 10 mL of THF/n-hexane (1:
3). The resulting deep red mixture was stirred at room
temperature for 2 h and filtrated, and deep red crystals were
formed at -40 °C within 48 h. The crystals were separated to
give 189 mg (81%) of 3, mp 142 °C. Anal. Calcd for C25H29NZr
(434.78): C, 69.11; H, 6.75; N, 3.22. Found: C, 68.75; H, 7.15;
N, 3.16. 1H NMR (benzene-d6): δ -0.9 (br, 1H, CH2-vipy), 1.3-
1.7, 1.9-2.3 (2 m, 17H, CH2), 4.67 (t, J ) 9.2 Hz, 1H, CH-
vipy), 5.02, 5.28, 5.44 (3 br, 6H, CH-thi), 5.53 (t, J ) 6.2 Hz,
1.2 Hz, 1H, py-5), 6.23 (m, J ) 9.1, 6.1, 1.4 Hz, 1H, py-4), 6.61
(m, J ) 9.1, 6.1 Hz, 1H, py-3), 7.31 (d, J ) 6.3 Hz, 1H, py-6).
13C{1H} NMR (benzene-d6): δ 23.9, 24.1, 24.5, 25.2 (CH2-thi),
56.4 (CH2-vipy), 88.2 (CH-vipy), 103.8, 104.4, 105.5 (CH-thi),
117.4, 117.7 (Cq-thi), 119.4, 123.9, 139.1, 145.9 (CH, py), 139.9
(Cq-py). MS (70 eV) m/z: 433 [(thi)2Zr(vipy)]+.
Diflu or id es. rac-(ebthi)ZrF2 (7) was described and charac-
terized before.4c New synthetic procedures for 7: (A) By
exchange reactions: (i) rac-(ebthi)ZrCl2 (477 mg, 1.12 mmol)
and Me3SnF (614 mg, 3.36 mmol) were stirred in dichlo-
romethane at room temperature for 2 h. After filtration the
solvent was removed in vacuo, and the remaining Me3SnCl
was removed by sublimation at 60 °C (3 × 10-1 mbar) to yield
7 as a white product (338 mg, 77%). (ii) rac-(ebthi)ZrCl2 (500
mg, 1.17 mmol) and ZnF2 (133 mg, 1.29 mmol) were stirred in
acetone at room temperature for 3 days. After filtration the
solvent was concentrated in vacuo, ether was added, and the
precipitate formed at -78 °C was isolated by filtration and
dried in vacuo to yield 7 (97 mg, 21%). (B) By acidolysis
reactions: (i) Complex 7 was prepared first4c from rac-(ebthi)-
Zr(2-vipy) with HBF4 etherate (yield 73%, but badly repro-
duceable). (ii) rac-(ebthi)Zr(2-vipy) (195 mg, 0.42 mmol) was
dissolved in toluene, and NEt3‚3HF (46 µL, 0.28 mmol) was
added. The solution was stirred for 5 h. After filtration the
filtrate was concentrated in vacuo and n-hexane was added.
At -78 °C white crystals of 7 (70 mg, 42%) appeared. (iii) rac-
(ebthi)ZrMe2 (322 mg, 0.83 mmol) was dissolved in toluene,
and NEt3‚3HF (91 µL, 0.56 mmol) was added. The solution
was stirred for 5 h, and after filtration the filtrate was
concentrated in vacuo. n-Hexane was added, and white crystals
of 7 (65 mg, 20%) appeared at -78 °C.
Me2Si(η5-C5H4)2Zr (2-vip y) (4). Me2Si(η5-C5H4)2Zr(py)(η2-
btmsa)7c (738 mg, 1.4 mmol) was dissolved in THF/n-hexane
(1:3), and 2-vinylpyridine (151 µL, 1.4 mmol) was added. The
color changed immediately to red, and the solution was stirred
for 1 h. After filtration red crystals of 4 (420 mg, 78%) were
obtained at -78 °C, mp 138 °C. Anal. Calcd for C19H21NSiZr
(382.69): C, 59.63; H, 5.53; N, 3.66. Found: C, 59.55; H, 5.32;
N, 3.48. 1H NMR (benzene-d6): δ -0.77, 3.31 (2 br t, 1H each,
Zr-CH2); 0.40 (s, 6H, SiMe2); 4.45 (t, 1H, 3J ) 9.7 Hz,
metallacyclic CH); 4.95, 5.09, 5.16, 5.45, 5.85 (5 m, 1H each,
3
4
C5H4); 5.44 (dt, 1H, J ) 6.2 Hz, J ) 1.0 Hz, Py-5); 5.65 (m,
3H, C5H4); 6.33 (ddd, 1H, 3J ) 8.9 and 6.1 Hz, 4J ) 1.4 Hz,
Py-4); 6.46 (d, 1H, 3J ) 8.9 Hz, Py-3); 7.42 (d, 1H, 3J ) 6.4 Hz,
Py-6). 13C NMR (benzene-d6): δ -5.2, -4.8 (2 Si-Me); 51.0 (Zr-
CH2); 88.3 (metallacyclic CH); 101.9, 102.5, 103.1, 103.8
(enhanced intensity), 109.4, 110.6, 115.5 (C5H4); 103.8 (Py-5);
122.9 (Py-3); 128.4 (Py-4); 139.3 (Py-2); 146.0 (Py-6). MS (70
eV) m/z: 381 [Me2Si(η5-C5H4)2Zr(2-vipy)]+.
(th i)2Zr F 2 (8). (thi)2ZrCl2 (684 mg, 1.71 mmol) and Me3-
SnF (656, 3.59 mmol) were stirred in dichloromethane at room
temperature for 4 h. After filtration the filtrate was concen-
trated in vacuo and n-hexane was added. A white product, 8
(163 mg, 26%), crystallized at -30 °C, mp 128 °C. Anal. Calcd
for C18H22F2Zr (367.59): C, 58.82; H, 6.03. Found: C, 58.75;
H, 6.05. 1H NMR (CDCl3): δ 1.67 (m, 2H, 5- and 6-H); 1.75
(m, 2H, 5- and 6-H); 2.51 (dt, 2H, 4- and 7-H); 2.62 (dt, 2H, 4-
(i)2Zr (2-vip y) (5). 2-Vinylpyridine (78.0 µL, 0.72 mmol) was
added by a syringe to a solution of (i)2Zr(THF)(η2-btmsa) (1)
(409 mg, 0.72 mmol) in 10 mL of THF/n-hexane, 1:3. The
resulting deep red mixture was stirred 4 h at room tempera-
ture and filtrated, and deep red crystals formed at -40 °C
3
3
and 7-H); 5.77 (d, 2H, J ) 3.1 Hz, 1- and 3-H); 6.44 (t, 1H, J
) 3.1 Hz, 2-H). 13C NMR (CDCl3): δ 22.6 (C5, C6); 23.5 (t,
J C,F ) 2 Hz, C4, C7); 108.2 (C1, C3); 110.5 (C2); 131.0 (C3a,

3824 Organometallics, Vol. 23, No. 16, 2004
Spannenberg et al.
) 3.0 Hz, 3-H); 5.96 (dd, 1H, J ) 3.2 Hz, J H,F ) 4.8 Hz, 12-
C7a). 19F NMR (CDCl3): δ 21.8. MS (70 eV) m/z: 366
3
3
3
[(thi)2ZrF2]+.
H); 6.52 (dd, 1H, J ) 5.7 and 7.5 Hz, Py-5); 6.73 (d, 1H, J )
7.5 Hz, Py-3); 6.88 (dt, 1H, 3J ) 7.5 Hz, 4J ) 1.7 Hz, Py-4);
3
4
9.13 (“t”, 1H, J ) 7.7 Hz, J ) 1.7 Hz, J H,F ) 6.4 Hz, Py-6).
13C NMR (benzene-d6): δ 22.8 (J C,F ) 2.4 Hz), 22.9, 23.2, 23.3
(J C,F ) 1.9 Hz), 23.4, 23.8 (J C,F ) 4.4 Hz), 24.3 (J C,F ) 2.0 Hz),
24.7, 26.9, 28.2 (10 × CH2 ebthi); 40.4 (1J C,H ) 125 Hz, Py-
CH2); 41.8 (1J C,H ) 119 Hz, J C,F ) 8.0 Hz, Zr-CH2); 104.1 (C2);
105.9 (J C,F ) 4.4 Hz, C12); 110.7 (C3); 112.0 (J C,F ) 4.7 Hz,
C13); 116.7 (J C,F ) 2.6 Hz), 122.2 (J C,F ) 2.3 Hz), 124.7 (J C,F
2.4 Hz), 125.3, 128.3, 128.8 (6 × quart.); 120.4 (J C,F ) 2.7 Hz,
Py-5); 121.7 (Py-3); 137.5 (J C,F ) 1.7 Hz, Py-4); 149.7 (J C,F
)
)
Me4C2(η5-C5H4)2Zr F 2 (9). Me4C2(η5-C5H4)2ZrCl2 (400 mg,
1.07 mmol) and Me3SnF (410 mg, 2.24 mmol) were stirred in
dichloromethane at room temperature for 1 h. Then the
reaction mixture was filtered, and the filtrate was concentrated
in vacuo. n-Hexane was added, and a mixture of Me4C2(η5-
C5H4)2ZrF2 and Me3SnCl crystallized at -30 °C. Me3SnCl was
removed by sublimation at 60 °C (3 × 10-1 mbar). The white
product, 9 (183 mg, 50%), remained, mp 178 °C. Anal. Calcd
for C16H20F2Zr (341.55): C, 56.27; H, 5.90. Found: C, 56.09;
24.9 Hz, Py-6); 170.1 (J C,F ) 0.9 Hz, Py-2). 19F NMR (benzene-
d6): δ -52. MS (70 eV) m/z: 479 [(ebthi)Zr(F)(CH2CH2-2-Py)]+.
(th i)2Zr (F )(CH2CH2-2-P y) (13). NEt3‚3HF (37 µL, 0.23
mmol) was added to (thi)2Zr(2-vipy) (3) (300 mg, 0.69 mmol),
dissolved in 20 mL of toluene. The solution was stirred until
the solution became colorless. Then the solution was filtered,
the filtrate was concentrated in vacuo, n-hexane was added,
and 13 (100 mg, 32%) crystallized at -30 °C, mp 119 °C. Anal.
Calcd for C25H30FNZr (454.74): C, 66.03; H, 6.65; N, 3.08.
Found: C, 66.00; H, 6.95; N, 3.03. 1H NMR (benzene-d6): δ
1.11 (“t”, 2H, Zr-CH2); 1.28, 1.38, 1.46, 1.62 (4 m, 2H each,
4-H and 5-H); 2.07, 2.31, 2.50, 2.89 (4 ddd, 2H each, 4-H and
7-H); 3.44 (“t”, 2H, Py-CH2); 5.39, 5.59 (2 dd, 2H each, 3J )
1
H, 5.81. H NMR (benzene-d6): δ 1.08 (s, 12H, Me); 5.78 (m,
4H, R-H Cp); 6.30 (m, 4H, â-H Cp). 13C NMR (benzene-d6): δ
28.3 (Me); 44.5 (CMe2); 108.2 (R-C Cp); 120.5 (â-C Cp); 143.0
(quart.). 19F NMR (benzene-d6): δ 25. MS (70 eV) m/z: 340
[Me4C2Cp2ZrF2]+.
3
3.1 Hz, J H,F ) 2.2 Hz, 1-H and 3-H); 5.52 (t, 2H, J ) 3.1 Hz,
Me2Si(η5-C9H 10)2Zr F 2 (10). A suspension of Me2Si(η5-
C9H10)2ZrMe2 (500 mg, 1.2 mmol) and NH4BF4 (126 mg, 1.2
mmol) in toluene was stirred at 90 °C for 48 h. Then the
reaction mixture was filtered, and the filtrate was concentrated
in vacuo. n-Hexane was added, and 10 (153 mg, 30%) crystal-
lized at -30 °C, mp 234 °C. Anal. Calcd for C20H26F2SiZr
(423.73): C, 56.69; H, 6.18. Found: C, 56.35; H, 6.03. 1H NMR
(benzene-d6): δ 0.48 (s, 9H, SiMe2); 1.40 (m, 2H, 5-H); 1.45
(m, 2H, 6-H); 1.78 (m, 2H, 6-H); 1.89 (m, 2H, 5-H); 2.34 (“t”,
3
3
2-H); 6.53 (dd, 1H, J ) 7.3 and 5.3 Hz, Py-5); 6.71 (d, 1H, J
3
4
) 7.5 Hz, Py-3); 6.87 (dt, 1H, J ) 7.5 Hz, J ) 1.5 Hz, Py-4);
3
4
9.08 (“t”, 1H, J ) 5.6 Hz, J ) 1.5 Hz, J H,F ) 6.7 Hz, Py-6).
13C NMR (benzene-d6): δ 23.4, 23.4 (C5/6); 24.3 (J C,F ) 2.9
Hz); 24.7 (J C,F ) 8.4 Hz, C4/7); 39.3 (2J C,F ) 10.1 Hz, Zr-CH2);
40.6 (Py-CH2); 101.6, 105.8, 111.5 (C1/2/3); 122.9 (J C,F ) 1.5
Hz), 126.8 (J C,F ) 2.7 Hz, C3a/7a); 120.4 (J C,F ) 3.3 Hz, Py-5);
122.2 (Py-3); 137.8 (J C,F ) 2.1 Hz, Py-4); 149.5 (J C,F ) 28.2
Hz, Py-6); 170.9 (J C,F ) 1 Hz, Py-2). 19F NMR (benzene-d6): δ
-47.2. MS (70 eV) m/z: 453 [(thi)2Zr(F)(CH2CH2-2-Py)]+.
Me2Si(η5-C5H4)2Zr (F )(CH2CH2-2-P y) (14). NEt3‚3HF (60
µL, 0.37 mmol) was added to Me2Si(η5-C5H4)2Zr(2-vipy) (4) (425
mg, 1.11 mmol) in 20 mL of toluene. The reaction mixture was
stirred for 2 h. After filtration the filtrate was concentrated
in vacuo, n-hexane was added, and 14 (94 mg, 21%) crystal-
lized at -30 °C, mp 185 °C. Anal. Calcd for C19H22FNSiZr
(402.69): C, 56.67; H, 5.51; N, 3.48. Found: C, 56.34; H, 5.47;
N, 3.07. 1H NMR (benzene-d6): δ 0.28, 0.49 (2 s, 3H each, Me2-
Si); 1.05 (“t”, 2H, Zr-CH2); 3.34 (“t”, 2H, Py-CH2); 5.56, 6.01,
6.23, 6.34 (4 m, 2H each, C5H4); 6.56 (dd, 1H, 3J ) 7.5 and 5.5
2
3
4H, 7-H); 2.40 (dt, 2H, J ) 16 Hz, J ) 6 Hz, 4-H); 2.81 (ddd,
2
3
3
2H, J ) 16 Hz, J ) 6 and 8 Hz, 4-H); 5.44 (d, J ) 3.0 Hz,
2-H); 6,33, (dt, J H,H ) 3.0 Hz, J H,F ) 1.5 Hz; 3-H). 13C NMR
3
(benzene-d6): δ -2.1 (SiMe2); 22.4 (C5); 23.1 (C6); 24.0 (t, J C,F
) 1.5 Hz, C4); 26.3 (C7); 105.7 (C1); 111.8 (t, J C,F ) 1.5 Hz,
C2); 121.5 (t, J C,F ) 1 Hz, C3); 126.7, 136.5 (C3a, C7a). 19F
NMR (benzene-d6): δ 29.6. 29Si NMR (benzene-d6): δ -14.1
(2J Si,H ) 6.9 Hz). MS (70 eV) m/z: 422 [Me2Si(η5-C9H10)2ZrF2]+.
Mon oflu or id es: Cp 2Zr (F )(CH2CH2-2-P y) (11). NEt3‚3HF
(83 µL, 0.51 mmol) was added to Cp2Zr(2-vipy)4c (2a ) (500 mg,
1.53 mmol), dissolved in 20 mL of toluene. The reaction
mixture was stirred at 60 °C until the solution became
colorless. After filtration the filtrate was concentrated in vacuo,
n-hexane was added, and 11 (154 mg, 29%) crystallized at -30
°C, mp 98 °C. Anal. Calcd for C17H18FNZr (346.56): C, 58.92;
3
3
Hz, Py-5); 6.74 (d, 1H, J ) 7.5 Hz, Py-3); 6.91 (dt, 1H, J )
4
3
7.5 Hz, J ) 1.2 Hz, Py-4); 9.20 (dd, 1H, J ) 5.5 Hz, J H,F ) 7
Hz, Py-6). 13C NMR (benzene-d6): δ -6.2, -3.5 (2 Me); 40.5
(Py-CH2); 42.6 (J C,F ) 9.4 Hz, Zr-CH2); 104.7, 107.5, 114.6,
114.9 (J C,F ) 2 Hz), 125.8 (J C,F ) 4.8 Hz, 5 × C5H4); 120.9 (J C,F
) 3.5 Hz, Py-5); 122.0 (Py-3); 137.7 (J C,F ) 2 Hz, Py-4); 149.4
(J C,F ) 28.5 Hz, Py-6); 169.9 (Py-2). 19F NMR (benzene-d6): δ
-57.7. MS (70 eV) m/z: 401 [Me2Si(η5-C5H4)2Zr(F)(CH2CH2-
2-Py)]+.
1
H, 5.24; N, 4.04. Found: C, 58.59; H, 4.97; N, 3.65. H NMR
(benzene-d6): δ 1.03 (“t”, 2H, Zr-CH2); 3.33 (“t”, 2H, Py-CH2);
2
3
5.82 (d, 10H, J H,F ) 1.6 Hz, Cp); 6.55 (dd, 1H, J ) 7.3 and
3
3
5.6 Hz, Py-5); 6.71 (d, 1H, J ) 7.7 Hz, Py-3); 6.90 (dt, 1H, J
4
3
) 7.3 and 7.7 Hz, J ) 1.8 Hz, Py-4); 9.13 (“dd”, 1H, J ) 5.6
Hz, J H,F ) 7.2 Hz, Py-6). 13C NMR (benzene-d6): δ 40.3 (1J C,H
) 120 Hz, J C,F ) 10 Hz, Zr-CH2); 40.4 (1J C,H ) 127 Hz, Py-
CH2); 110.9 (J C,F ) 2 Hz, Cp); 120.8 (J C,F ) 4 Hz, Py-5); 121.9
(Py-3); 137.8 (Py-4); 149.8 (J C,F ) 29 Hz, Py-6); 170.3 (Py-2).
19F NMR (benzene-d6): δ -68.4.
Me2Si(η5-C9H10)2Zr F (Me) (15). NEt3‚3HF (60 µL, 0.37
mmol) was added to Me2Si(η5-C9H10)2ZrMe2 (461 mg, 1.11
mmol), dissolved in 20 mL of toluene. The solution was stirred
for 2 h. Then the solution was filtered, the filtrate was
concentrated in vacuo, n-hexane was added, and 15 (186 mg,
40%) crystallized at -30 °C. Me2Si(η5-C9H10)2ZrF2 (10) may
form as a side product and must be removed by sublimation
r a c-(ebth i)Zr (F )(CH2CH2-2-P y) (12). NEt3‚3HF (42 µL,
0.26 mmol) was added to rac-(ebthi)Zr(2-vipy)4c (359 mg, 0.78
mmol), dissolved in 20 mL of toluene. The reaction mixture
was stirred until the solution became colorless. After filtration
the filtrate was concentrated in vacuo, n-hexane was added,
and 12 (199 mg, 53%) crystallized at -30 °C. Mp: 135 °C. Anal.
Calcd for C27H32FNZr (480.78): C, 67.45; H, 6.71; N, 2.91.
(90 °C, 3 × 10-1 mbar). Mp: 172 °C. Anal. Calcd for C21H29
-
FSiZr (419.77): C, 60.09; H, 6.96. Found: C, 60.47; H, 6.75.
1H NMR (benzene-d6): δ 0.34, 0.49 (2 s, 3H each, Me2Si); 0.40
3
3
(d, 3H, J H,F ) 2.5 Hz, Zr-Me); 4.88 (d, 1H, J ) 3.0 Hz); 5.69
3
3
(d, 1H, J ) 3.1 Hz); 6.01 (dd, 1H, J ) 3.1 Hz, J H,F ) 2.1 Hz);
6.53 (d, 1H, 3J ) 3.0 Hz); CH2 not analyzed. 13C NMR (benzene-
d6): δ -2.2, -2.2 (2 Si-Me); 28.7 (Zr-Me); 22.6 (J C,F ) 3.7 Hz),
22.7, 23.3, 23.4, 23.9 (J C,F ) 3.0 Hz), 24.7, 26.1, 26.3 (8 × CH2);
100.0, 102.4 (2 × Si-C); 111.1, 111.2, 117.7, 121.5 (4 × CH);
1
Found: C, 67.16; H, 6.81; N, 2.81. H NMR (benzene-d6, CH2
signals omitted): δ 0.83, 1.23 (2 m, 1H each, Zr-CH2); 3.35,
3
3.61 (2 m, 1H each, Py-CH2); 5.14 (d, 1H, J ) 3.0 Hz, 2-H);
5.76 (dd, 1H, 3J ) 3.2 Hz, J H,F ) 3.9 Hz, 13-H); 5.87 (d, 1H, 3J

Zirconocene Difluoride Complexes
Organometallics, Vol. 23, No. 16, 2004 3825
125.0, 127.0, 131.5, 133.8 (4 × quart.). 19F NMR (benzene-d6):
δ 51.7. 29Si NMR (benzene-d6): δ 14.8 (2J Si,H ) 6.8 Hz). MS
(70 eV) m/z: 403 [Me2Si(η5-C9H10)2ZrF]+.
X-r a y Cr ysta llogr a p h ic Stu d y of Com p lexes 3, 8, a n d
13. Data were collected with a STOE-IPDS-diffractometer
using graphite-monochromated Mo KR radiation. The struc-
tures were solved by direct methods (SHELXS-97)13 and
refined by full-matrix least-squares techniques against F2
(SHELXL-97).14 XP (Bruker AXS) was used for structure
representations. The absolute structure of 3 was determined
through the Flack parameter x ) -0.03(5).
Ack n ow led gm en t. We are grateful to the Fonds der
Chemischen Industrie and the Deutsche Forschungs-
gemeinschaft (Project-Nr. AR 321/1-1 and SPP1118) for
support of this work.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic data in cif file format, including bond lengths and
angles of compounds 8 (data_813), 13 (data_817), and 3
(data_820). This material is available free of charge via the
Internet at http://pubs.acs.org.
OM049745U
(13) Sheldrick, G. M. SHELXS-97; University of Go¨ttingen: Ger-
many, 1997.
(14) Sheldrick, G. M. SHELXL-97; University of Go¨ttingen: Ger-
many, 1997.