Preparation and characterization of a zwitterionic (iminopyrrolyl)zirconium complex with benzylaluminate anion and its catalytic performance for 1-hexene polymerization

Article abstract of DOI:10.1021/om060692l

An alkyl abstraction from (DIP-pyr)Zr(CH₂Ph)₃ (DIP-pyr = 2-{N-(2,6-diisopropylphenyl)iminomethyl}pyrrolyl) using Al(C ₆F₅)₃ affords a zwitterionic dibenzyl complex, [(DIP-pyr)Zr(CH₂Ph)₂][η⁶-PhCH ₂Al(C₆F₅)₃] (2), which becomes an active catalyst for 1-hexene polymerization. The similar reaction by using B(C₆F₅)₃ affords a less stable adduct. The more stable character of 2 is ascribed to the tight ion-pair formation between the zirconium cation and the benzyl aluminate anion.

Full text of DOI:10.1021/om060692l

5210
Organometallics 2006, 25, 5210-5212
Preparation and Characterization of a Zwitterionic
(Iminopyrrolyl)zirconium Complex with Benzylaluminate Anion and
Its Catalytic Performance for 1-Hexene Polymerization
Hayato Tsurugi and Kazushi Mashima*
Department of Chemistry, Graduate School of Engineering Science, Osaka UniVersity,
Toyonaka, Osaka 560-8531, Japan
ReceiVed August 1, 2006
Summary: An alkyl abstraction from (DIP-pyr)Zr(CH2Ph)3
(DIP-pyr ) 2-{N-(2,6-diisopropylphenyl)iminomethyl}pyrrolyl)
using Al(C6F5)3 affords a zwitterionic dibenzyl complex, [(DIP-
pyr)Zr(CH2Ph)2][η6-PhCH2Al(C6F5)3] (2), which becomes an
actiVe catalyst for 1-hexene polymerization. The similar reaction
by using B(C6F5)3 affords a less stable adduct. The more stable
character of 2 is ascribed to the tight ion-pair formation between
the zirconium cation and the benzyl aluminate anion.
transfer from aluminum to zirconium.6 Another feature of
the reaction between Al(C6F5)3 and dimethyl zirconocene is
that the alane adduct forms a more tightly bound ion pair.
Landis and his co-workers revealed by the X-ray analyses of
(C5Me4H)2ZrCH3{µ-CH3M(C6F5)3} (M ) B, Al) that the bond
distance of Zr-(CH3)bridge was shorter for the alane adduct (2.51
Å) than for the borane adduct (Zr-(CH3)bridge
: 2.60 Å),
indicating tight ion-pair formation for the Al(C6F5)3 adduct.7
Marks et al. also reported a similar trend by the structural and
thermochemical analyses of B(C6F5)3- and Al(C6F5)3-derived
metallocenium ion pairs.5o
The weakly coordinating anions of R-olefin polymerization
catalysts have an important role as counterparts of the cationic
early transition metal alkyl complexes, and the anions affect
the molecular weight, branching, and microstructure of the
resulting polyolefins.1 The use of perfluoroaryl borate counter-
anions in metallocene catalysts enhances not only the thermal
stability but also the catalytic activity of cationic alkyl species.2
Moreover, the interaction between metallocene precursors and
Lewis acidic organoboranes was elucidated by several research
groups.3 In sharp contrast, the interaction between organoalane,
Al(C6F5)3,4 and alkyl complexes of metallocene and nonmet-
allocene catalyst precursors has attracted less attention.5 Boch-
mann et al. reported that the mixture of Cp2ZrMe2 and Al(C6F5)3
produced a less stable zwitterionic adduct than that of Cp2ZrMe2
and B(C6F5)3, due to the facile decomposition by the C6F5 group
Bochmann, Fujita, Okuda, and our group independently
reported the preparation and R-olefin polymerization activities
of group 4 metal iminopyrrolyl complexes.8 Our continuing
efforts to synthesize iminopyrrolyl complexes of group 4 metals
(5) (a) Cowley, A. H.; Hair, G. S.; McBurnett, B. G.; Jones, R. A. Chem.
Commun. 1999, 437. (b) Vanka, K.; Chan, M. S. W.; Pye, C. C.; Ziegler,
T. Organometallics 2000, 19, 1841. (c) Chen, E. Y.-X.; Kruper, W. J.; Roof,
G.; Wilson, D. R. J. Am. Chem. Soc. 2001, 123, 745. (d) Jin, J.; Chen, E.
Y.-X. Organometallics 2002, 21, 13. (e) Feng, S.; Roof, G. R.; Chen, E.
Y.-X. Organometallics 2002, 21, 832. (f) Jin, J.; Wilson, D. R.; Chen, E.
Y.-X. Chem. Commun. 2002, 708. (g) Bolig, A. D.; Chen, E. Y.-X. J. Am.
Chem. Soc. 2002, 124, 5612. (h) Kumar, K. R.; Hall, C.; Penciu, A.; Drewitt,
M. J.; Mcinenly, P. J.; Baird, M. C. J. Polym. Sci, A: Polym. Chem. 2002,
40, 3302. (i) Jin, J.; Mariott, W. R.; Chen, E. Y.-X. J. Polym. Sci, A: Polym.
Chem. 2003, 41, 3132. (j) Chen, E. Y.-X.; Cooney, M. J. J. Am. Chem.
Soc. 2003, 125, 7150. (k) Rodriguez-Delgado, A.; Chen, E. Y.-X. Inorg.
Chim. Acta 2004, 357, 3911. (l) Chen, E. Y.-X. J. Polym. Sci, A: Polym.
Chem. 2004, 42, 3395. (m) Bolig, A. D.; Chen, E. Y.-X. J. Am. Chem.
Soc. 2004, 126, 4897. (n) Rodriguez-Delgado, A.; Chen, E. Y.-X. J. Am.
Chem. Soc. 2005, 127, 961. (o) Stahl, N. G.; Salata, M. R.; Marks, T. J. J.
Am. Chem. Soc. 2005, 127, 10898.
* Corresponding author. E-mail: mashima@chem.es.osaka-u.ac.jp.
Fax: 81-6-6850-6296.
(1) (a) Piers, W. E.; Chivers, T. Chem. Soc. ReV. 1997, 26, 345. (b) Chen,
E. Y.-X.; Marks, T. J. Chem. ReV. 2000, 100, 1391. (c) Pedeutour, J.;
Radhakrishnam, K.; Cramail, H.; Deffieux, A. Macromol. Rapid. Commun.
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Kim, K. H.; Lee, B. Y.; Oh, J. S. J. Mol. Catal. A: Chem. 1998, 132, 231.
(c) Hair, G. S.; Cowley, A. H.; Jones, R. A.; McBurnett, B. G.; Voigt, A.
J. Am. Chem. Soc. 1999, 121, 4922. (d) Klosin, J.; Roof, G. R.; Chen, E.
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(8) (a) For a review of iminopyrrolyl complexes: Mashima, K.; Tsurugi,
H. J. Organomet. Chem. 2005, 690, 4414. For group 4 metal iminopyrrolyl
complexes; use of Ti: (b) Yoshida, Y.; Matsui, S.; Takagi, Y.; Mitani, M.;
Nitabaru, M.; Nakano, T.; Tanaka, H.; Fujita, T. Chem. Lett. 2000, 29,
1270. (c) Yoshida, Y.; Matsui, S.; Takagi, Y.; Mitani, M.; Nakano, T.;
Tanaka, H.; Kashiwa, N.; Fujita, T. Organometallics 2001, 20, 4793. (d)
Yoshida, Y.; Saito, J.; Mitani, M.; Takagi, Y.; Matsui, S.; Ishii, S.; Nakano,
T.; Kashiwa, N.; Fujita, T. Chem. Commun. 2002, 1298. (e) Yoshida, Y.;
Mohri, J.; Ishii, S.; Mitani, M.; Saito, J.; Matsui, S.; Makio, H.; Nakano,
T.; Tanaka, H.; Onda, M.; Yamamoto, Y.; Mizuno, A.; Fujita, T. J. Am.
Chem. Soc. 2004, 126, 12023. (f) Yoshida, Y.; Matsui, S.; Fujita, T. J.
Organomet. Chem. 2005, 690, 4382. Use of Zr and Hf: (g) Dawson, D.
M.; Walker, D. A.; Thornton-Pett, M.; Bochmann, M. J. Chem. Soc., Dalton
Trans. 2000, 459. (h) Matsuo, Y.; Mashima, K.; Tani, K. Chem. Lett. 2000,
29, 1114. (i) Tsurugi, H.; Yamagata, T.; Tani, K.; Mashima, K. Chem. Lett.
2003, 32, 756. (j) Matsui, S.; Spaniol, T. P.; Takagi, Y.; Yoshida, Y.; Okuda,
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Takagi, Y.; Spaniol, T. P.; Okuda, J. J. Organomet. Chem. 2004, 689, 1155.
(l) Yasumoto, T.; Yamagata, T.; Mashima, K. Organometallics 2005, 24,
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2006, 254, 131.
10.1021/om060692l CCC: $33.50 © 2006 American Chemical Society
Publication on Web 09/21/2006

Communications
Organometallics, Vol. 25, No. 22, 2006 5211
have been extended to isolate the cationic alkyl complexes
applicable to the R-olefin polymerization reaction. During the
course of our studies, we found that the Al(C6F5)3-derived anion
[PhCH2Al(C6F5)3]- was suitable for stabilizing a coordinatively
unsaturated metal center, while the corresponding B(C6F5)3-
derived adduct was too unstable to be isolated. Herein, we
describe the synthesis of zwitterionic dibenzyl complexes [(DIP-
pyr)Zr(CH2Ph)2][η6-PhCH2Al(C6F5)3] (2) and revealed the mo-
lecular structure by an X-ray diffraction study. This is the first
example of a zwitterionic complex with an η6-benzylaluminate
anion. The 1-hexene polymerization behavior of 2 and the
product between (DIP-pyr)Zr(CH2Ph)3 (1) and B(C6F5)3 is also
disclosed.
Treatment of (DIP-pyr)Zr(CH2Ph)3 (1) (DIP-pyr ) 2-{N-(2,6-
diisopropylphenyl)iminomethyl}pyrrolyl)8i with an equimolar
amount of tris(pentafluorophenyl)alane in bromobenzene af-
forded the corresponding zwitterionic complex, [(DIP-pyr)Zr-
(CH2Ph)2][η6-PhCH2Al(C6F5)3] (2) (eq 1), which was sparingly
soluble in aromatic solvents.9 The Al(C6F5)3 adduct 2 was stable
at room temperature for several hours. The 1H NMR spectrum
displayed the benzylic proton resonance bound to aluminum at
Figure 1. Molecular structure of 2. All hydrogen atoms and toluene
are omitted for clarity.
1
δ 3.08. The notable feature in the H NMR spectrum was the
upfield shift of [PhCH2Al(C6F5)3]- that was observed as broad
resonances at δH 7.20, 6.58, and 5.79, assignable to ortho, meta,
and para protons, respectively. The upfield shift of the aromatic
resonances of [PhCH2Al(C6F5)3]- suggested the presence of a
cation-anion interaction through the η6-coordination of [η6-
Table 1. Selected Bond Distances (Å) and Angles (deg) of 2
Zr-N1
2.203(4)
2.290(5)
2.898(4)
2.593(4)
2.760(5)
2.033(5)
Zr -N2
Zr-C25
Zr-C34
Zr-C36
Zr-C38
2.361(4)
2.257(5)
2.697(4)
2.656(4)
2.844(5)
Zr-C18
Zr-C33
Zr-C35
Zr-C37
Al-C32
PhCH2Al(C6F5)3]- to the cationic zirconium atom.10 In the 19
F
NMR spectrum, three sharp resonances, corresponding to the
ortho, para, and meta fluorine atoms, were observed at δF
-122.1, -155.8, and -162.7. The reaction of 1 with 1 equiv
of B(C6F5)3 in bromobenzene, followed by recrystallization at
-30 °C, gave orange microcrystals of [(DIP-pyr)Zr(CH2Ph)2]-
[PhCH2B(C6F5)3] (3) in 86% yield, whose full characterization
by NMR spectroscopy resulted in failure due to the poor
solubility and the thermal instability in solution. The stability
of 2 compared to 3 may reflect the tight ion-pair formation of
the Al(C6F5)3 adduct, and the stronger interaction between the
benzylaluminate anion and the zirconium atom is in accordance
with the trend of cation-anion interactions in B(C6F5)3- and
Al(C6F5)3-derived metallocenium ion pairs.5o,7
N1-Zr-N2
71.9(1)
82.0(2)
123.4(2)
112.7(3)
109.0(3)
N1-Zr-C18
N2-Zr-C18
C18-Zr-C25
Zr-C25-C26
81.3(2)
121.3(2)
102.2(2)
105.8(3)
N1-Zr-C25
N2-Zr-C25
Zr-C18-C19
Al-C32-C33
conium atom and carbon atoms of the η6-arene ring are 2.593-
(4)-2.898(4) Å, in the range typically observed for an η6-
(9) [(DIP-pyr)Zr(CH2Ph)2][η6-PhCH2Al(C6F5)3] (2): In a glovebox, (DIP-
pyr)Zr(CH2Ph)3 (62 mg, 0.10 mmol) and Al(C6F5)3toluene0.5 (58 mg, 0.10
mmol) were placed in a Schlenk vessel. Cold bromobenzene (-30 °C) was
added to the solid mixture, and the reaction mixture was shaken until each
component was dissolved. The solution was stored at -30 °C overnight,
and then orange microcrystals were formed. Hexane (ca. 5 mL) was added
to the reaction mixture, and the supernatant was separated. The orange
microcrystals were washed with hexane (1 mL) and dried in vacuo to give
orange microcrystals (94.2 mg, 82% yield), mp 99-105 °C (dec.). 1H NMR
3
(300 MHz, C6D5Br, 298 K): δ 7.44 (s, 1H, NdCH), 7.20 (br d, JH-H
)
5.7 Hz, 2H, o-Ph of η6-AlCH2Ph), 7.05-6.95 (aromatic protons), 6.87 (d,
3JH-H ) 6.3 Hz, 2H, m-Ar of 2,6-iPr2C6H3), 6.80 (m, 3H, p-Ph of ZrCH2-
Ph and pyrrolyl ring), 6.58 (br, 2H, m-Ph of η6-AlCH2Ph), 6.40 (br, 1H,
3
pyrrolyl ring), 6.30 (d, JH-H ) 6.9 Hz, 4H, o-Ph of ZrCH2Ph), 5.79 (br,
1H, p-Ph of η6-AlCH2Ph), 3.06 (br, 2H, AlCH2Ph), 2.76 (br, 4H, ZrCH2-
Ph), 1.55 (br, 2H, CHMe2), 0.78 (d, 3JH-H ) 6.0 Hz, 6H, CHMe2), 0.65 (d,
3JH-H ) 6.0 Hz, 6H, CHMe2). 19F NMR (282 MHz, C6D5Br, 298 K): δ
-122.1 (d, 3JF-F ) 20 Hz, 6F, ortho), -155.8 (t, 3JF-F ) 19 Hz, 3F, para),
-162.7 (m, 6F, meta).
Single crystals of 2 suitable for X-ray diffraction were
obtained by cooling a toluene/hexane solution of 2 to -30 °C.
The molecular structure is shown in Figure 1, and selected bond
distances and angles are listed in Table 1.11 Complex 2 is the
first example of a zwitterionic complex with an η6-benzylalu-
minate anion, although several structurally characterized group
4 metal zwitterionic complexes with η6-benzylborate3i,10,12 and
µ-methylaluminate5a,c,o,7 anions have been reported. Complex
2 has pseudo-trigonal bipyramidal geometry around the zirco-
nium atom, where the pyrrolyl nitrogen atom and the centroid
of the η6-phenyl ring occupy the apical position. Two benzyl
groups are bound to the zirconium atom in an η1-fashion, based
on the large bond angles of Zr-C(18)-C(19) [112.7(3)°] and
Zr-C25-C26 [105.8(3)°].3i,13 The distances between the zir-
(10) (a) Bochmann, M.; Karger, G.; Jaggar, A. J. J. Chem. Soc., Chem.
Commun. 1990, 1038. (b) Horton, A. D.; Frijns, J. H. G. Angew. Chem.,
Int. Ed. 1991, 30, 1152. (c) Pellecchia, C.; Grassi, A.; Immirzi, A. J. Am.
Chem. Soc. 1993, 115, 1160. (d) Gillis, D. J.; Tudoret, M. J.; Baird, M. C.
J. Am. Chem. Soc. 1993, 115, 2543. (e) Pellecchia, C.; Immirzi, A.; Grassi,
A.; Zambelli, A. Organometallics 1993, 12, 4473. (f) Lancaster, S. J.;
Robinson, O. B.; Bochmann, M.; Coles, S. J.; Hursthouse, M. B.
Organometallics 1995, 14, 2456.
(11) Crystal data for complex 2 ((C56H42N2F15AlZr)(C7H8), 120(1) K):
monoclinic, P21/n (No. 14), a ) 11.4095(15) Å, b ) 21.711(4) Å, c )
22.396(4) Å, V ) 5547.1(16) Å3, Z ) 4, Dcalcd ) 1.483 g cm-3, µ ) 3.07
cm-1, R1 ) 0.1336 and wR2 ) 0.1891 (all data), GOF ) 1.021.
(12) (a) Thorn, M. G.; Etheridge, Z. C.; Fanwick, P. E.; Rothwell, I. P.
J. Organomet. Chem. 1999, 591, 148. (b) Shafir, A.; Arnold, J. Organo-
metallics 2003, 22, 567.

5212 Organometallics, Vol. 25, No. 22, 2006
Communications
Table 2. 1-Hexene Polymerization Catalyzed by
coordinating arene ring. Two adjacent Zr-C(arene) distances,
Zr-C(33) [2.898(4) Å] and Zr-C(38) [2.844(5) Å], are longer
than the distances between zirconium and other carbon atoms,
deforming from the ideal η6-coordination, due to the steric
repulsion between the η6-coordinating arene ring and the bulky
{N-(2,6-diisopropylphenyl)iminomethyl}pyrrolyl ligand. It is
notable that zwitterionic zirconium complexes [(PhCH2)3Zr(η6-
PhCH2B(C6F5)3)],10c [CpZr(CH2Ph)2(η6-PhCH2B(C6F5)3)],10e [(2,6-
Ph2-3,5-Me2C6HO)2Zr(CH2Ph)(η6-PhCH2B(C6F5)3)],12a and [(1,1′-
Fc-(NSiMe3)2)Zr(CH2Ph)(η6-PhCH2B(C6F5)3)]12b had similar
asymmetry in the bonding of the benzyl borate anion to the
zirconium atom.
[(DIP-pyr)Zr(CH2Ph)2][η6-PhCH2Al(C6F5)3] (2)a
temp time yield
run (°C)
(h)
(%) activityb
Mn
Mw
Mw/Mn
1
2
3
4
5
0
6
1
3
6
6
49
23
77
92
83
3.5
9.7
11.0
6.6
7.2 × 104 1.3 × 105
4.6 × 104 8.4 × 104
4.6 × 104 8.6 × 104
4.0 × 104 7.3 × 104
2.1 × 104 4.0 × 104
1.8
1.8
1.9
1.8
1.9
rt
rt
rt
50
5.9
a Conditions: [cat.] ) 5 mM (5 µmol catalyst) in a C6H5Cl (0.70 mL)
and 1-hexene (0.32 mL, 500 equiv) mixture. Activity [kg polymer/mol
b
cat‚h].
The reactions of 1 with Lewis acid-base adducts (C6F5)3-
Al(THF) and (C6F5)3B(THF) were examined in order to stabilize
the cationic zirconium center by the coordination of the Lewis
base. The benzyl abstraction did not proceed by adding (C6F5)3-
Al(THF) to 1 because of the lower affinity of Al(C6F5)3 to the
benzyl anion compared to THF. This behavior was the same
toward other group 4 metal dimethyl complexes in the presence
of THF.5g,m On the other hand, mixing of 1 and 1 equiv of
(C6F5)3B(THF) in C6D5Br cleanly afforded an ionic species,
[(DIP-pyr)Zr(CH2Ph)2(THF)][(PhCH2)B(C6F5)3] (4) (eq 2),
which was stable at room temperature.14 The resonances of the
coordinating THF molecule were observed at δ 3.24 and 1.22
in the 1H NMR spectrum. In the 19F NMR, the ∆δ(m,p-F) was
2.8 ppm, indicating that the [PhCH2B(C6F5)3]- anion was
separated from the metal center.15 The quantitative formation
of 4 from 1 and (C6F5)3B(THF) suggests that B(C6F5)3 may
abstract a benzyl anion from the zirconium center to give 3 as
an ionic pair.
1-hexene polymerization was also investigated (runs 2-4), and
the values of Mn and Mw were almost the same among all runs,
suggesting that the catalytically active species does not have
1
living polymerization behavior. In the H NMR spectra of the
resulting polymers, the signal characteristic of the internal olefin
(δ 5.3-5.4) was observed,16 confirming that the termination
was a â-hydrogen elimination from the growing polymer chain.
We also examined the B(C6F5)3-derived complexes 3 and 4 for
1-hexene polymerization. In sharp contrast to the atactic poly-
(1-hexene)s obtained by 2, complex 3 afforded an isotactic-
rich poly(1-hexene) ([mmmm] up to 85%). The Lewis base-
stabilized adduct 4, which was generated in situ before adding
an excess amount of 1-hexene monomer, was inactive for the
1-hexene polymerization. Our preliminary study indicated that
3 showed low efficiency and broad molecular weight distribu-
tion,17 which might be associated with the rapid decomposition
of the active species. The ligand activation might be expected
to construct the active species for higher isotacticity,18 but the
details of the process are not clear yet.
In summary, we demonstrated the preparation of an
Al(C6F5)3-derived zwitterionic complex, [(DIP-pyr)Zr(CH2Ph)2]-
[η6-PhCH2Al(C6F5)3] (2), and the molecular structure of the
Al(C6F5)3 adduct 2 was revealed by X-ray analysis. The complex
3, prepared by mixing of 1 and B(C6F5)3, was too thermally
unstable to characterize. The difference in the stability of 2 and
3 may depend on the strength of the cation-anion interaction.
The Al(C6F5)3 adduct 2 was found to become an active catalyst
for 1-hexene polymerization with single-site character (Mw/Mn
< 2).
Polymerization of 1-hexene was conducted by Al(C6F5)3
adduct 2 in chlorobenzene, and the results are summarized in
Table 2. The resulting polymers had narrow molecular weight
distributions (Mw/Mn < 2), indicating that polymerization using
2 has a single-site character. The time dependency for the
Acknowledgment. One of the authors (H.T.) thanks the
Japan Society for the Promotion of Science (JSPS) Research
Fellowships for Young Scientists.
(13) (a) Latesky, S. L.; McMullen, A. K.; Niccolai, G. P.; Rothwell, I.
P.; Hoffman, J. C. Organometallics 1985, 4, 902. (b) Jordan, R. F.; Lapointe,
R. E.; Baenzinger, N.; Hinch, G. D. Organometallics 1990, 9, 1539.
(14) [(DIP-pyr)Zr(CH2Ph)2(THF)][PhCH2B(C6F5)3] (4): 1H NMR (300
MHz, C6D5Br, 298 K): δ 7.81 (s, 1H, NdCH), 7.2-6.8 (aromatic protons),
Supporting Information Available: Text giving experimental
details for the syntheses of all compounds, 1H and 19F NMR spectra
of 2 and 4, 1-hexene polymerization procedures, and CIF files
giving crystallographic data for 2. These materials are available
free of charge via the Internet at http://pubs.acs.org.
3
6.87 (d, 1H, JH-H ) 3.6 Hz, pyrrolyl ring), 6.27 (m, 1H, pyrrolyl ring),
3
6.17 (br d, JH-H ) 7.4 Hz, 4H, o-Ph of ZrCH2Ph), 3.34 (br, 2H, BCH2-
2
Ph), 3.24 (br, 4H, THF), 2.42 (br, 2H, CHMe2), 2.17 (br d, JH-H ) 11.3
Hz, 2H, ZrCHHPh), 1.93 (br, 2H, ZrCHHPh), 1.22 (br, 4H, THF), 1.02
(br, 6H, CHMe2), 0.86 (br d, 3JH-H ) 5.8 Hz, 6H, CHMe2). 13C NMR (75
MHz, C6D5Br, 308 K): δ 164.2 (d, 1JC-H ) 170 Hz, NdCH), 148.3, 148.1
OM060692L
(15) (a) Horton, A. D.; de With, J.; van der Linden, A. J.; van de Weg,
H. Organometallics 1996, 15, 2672. (b) Horton, A. D.; de With, J.
Organometallics 1997, 16, 5424.
(16) Liu, Z.; Somsook, E.; White, C. B.; Rosaaen, K. A.; Landis, C. R.
J. Am. Chem. Soc. 2001, 123, 11193.
1
1
(d, JC-F ) 244 Hz, o-C6F5), 141.1, 140.9 (d, JC-F ) 314 Hz, p-C6F5),
136.1 (d, 1JC-F ) 269 Hz, m-C6F5), 135.9, 131.3, 130.1, 129.2, 129.1, 128.5,
127.2, 126.6, 126.2, 124.0, 122.2, 116.2, 80 (br, ZrCH2), 75.7 (t, JC-H
1
)
1
1
157 Hz, THF), 28.6 (d, JC-H ) 125 Hz, CHMe2), 25.6 (q, JC-H ) 127
1
1
Hz, CHMe2), 24.5 (t, JC-H ) 129 Hz, THF), 21.7 (q, JC-H ) 127 Hz,
CHMe2), some carbon signals were overlapped with C6D5Br resonances.
(17) See Supporting Information.
(18) Boussie, T. R.; Diamond, G. M.; Goh, C.; Hall, K. A.; LaPointe,
A. M.; Leclerc, M. K.; Vince, Murphy, V.; Shoemaker, J. A. W.; Turner,
H.; Rosen, R. K.; Stevens, J. C.; Alfano, F.; Busico, V.; Cipullo, R.; Talarico,
G. Angew. Chem., Int. Ed. 2006, 45, 3278.
19F NMR (282 MHz, C6D5Br, 298 K): δ -131.5 (d, JF-F ) 22 Hz, 6F,
3
ortho), -164.7 (t, 3JF-F ) 21 Hz, 3F, para), -167.5 (t, 3JF-F ) 20 Hz, 6F,
meta).