R.M. Gauvin et al. / Journal of Organometallic Chemistry 658 (2002) 1ꢂ
/8
7
over an appropriate dehydrating agent, distilled under
˚
argon and stored under argon over activated 4 A
molecular sieves. Deuterated solvents were dried over
˚
activated 4 A molecular sieves. NMR spectra were
recorded on Bruker AC-300 or ARX-500 spectrometers.
Chemical shifts are given in ppm, with tetramethylsilane
as the reference. Coupling constants are given in Hz.
Activation energies were calculated using the Eyring
equation [9] or by the graphical method derivated from
it [8].
(m, 3H, HmꢃHp SiPhPh?), 7.00 (m, 2H, Ar ABA), 6.98
/
(t, 2H, Hm ZrCH2Ph), 6.84 (d, 1H, H3 ou H6 ABA), 6.82
(t, 1H, Hp ZrCH2Ph), 6.46 (d, broad, 1H, Ho BCH2Ph),
6.27 (d, 2H, Ho ZrCH2Ph), 6.07 (t, broad, 1H, Hm
BCH2Ph), 5.97 (broad, 1H, Hp BCH2Ph), 5.81 (t, broad,
1H, Hm BCH2Ph), 5.41 (broad, 1H, Ho BCH2Ph), 4.79
2
(d, broad, 1H, Jꢀ
/
14 Hz, 1H, CHH? ABA), 3.56 (d,
2
broad, Jꢀ
/
14 Hz, 1H, CHH? ABA), 3.49 (broad, 1H,
BCHH?Ph), 2.83 (broad, 1H, BCHH?Ph), 2.05 (broad,
1H, ZrCHH?Ph), 1.47 (d, 2Jꢀ
/11.9 Hz, 1H,
ZrCHH?Ph), 0.37 (s, 3H, SiMePh2), 0.03 (s, 9H,
SiMe3). 13C DEPT-135 NMR (C6D6, 75 MHz): d
135.33, 135.14, 135.05, 132.55, 131.74, 131.20, 131.09,
130.92, 129.14, 128.95, 128.69, 128.54, 128.31, 127.84,
125.86, 125.10, 123.63 (CH Ar), 71.1 (ZrCH2Ph), 53.48
4.2. [Zr(ABA1)(CH2Ph)][(h6-PhCH2)B(C6F5)3] (1)
In the glove-box, a solution of 20 mg of Zr(A-
BA1)(CH2Ph)2 (0.037 mmol) in 0.4 ml of CD2Cl2 was
introduced into an NMR tube, which was then placed in
an almost horizontal position. At the top of the NMR
tube were deposited 19 mg of B(C6F5)3 (0.037 mmol)
[13]. While still kept in the same position, the tube was
sealed with a rubber septum and cooled in dry ice. It was
then set upright again, vigorously shaken to ensure
efficient mixing of the reagents, and introduced in the
precooled NMR probe. NMR spectroscopy showed that
(CH2 ABA), 35.8 (broad, BCH2Ph), ꢁ
/
0.23 (SiMe3), ꢁ
/
0.32 (SiMePh2).
4.4. Zr(ABA2)(C6F5)2 (4)
A 1.6 M solution (0.115 ml) of n-BuLi (0.184 mmol)
in hexane was added to 0.023 ml of C6F5Br (0.184
mmol) in 10 ml of diethylether at ꢁ78 8C. A white
/
1
1 had formed in quantitative yield. H-NMR (CD2Cl2,
precipitate of C6F5Li built up rapidly [13]. After 1 h
stirring, 50 mg of Zr(ABA2)Cl2 (0.091 mmol) [4a] in 5 ml
of diethylether were added and the reaction mixture was
allowed to warm to room temperature (r.t.). After one
night, the mixture was centrifuged and the clear solution
was evaporated to dryness to yield 40 mg of a pale
yellow solid (54% yield). 1H-NMR (C6D6, 300 MHz): d
300 MHz, 230 K): d 7.48 (dt, 1H, H4 ABA), 7.27 (m,
2H, H5ꢃ
2H, Hpꢃ
1H, Hp ZrCH2Ph), 6.92 (d, 2H, Ho ZrCH2Ph), 6.60 (m,
2H, Hm2 Ho2 BCH2Ph), 5.96 (d, 1H, Ho1 BCH2Ph),
/
H6 ABA), 7.22 (t, 2H, Hm ZrCH2Ph), 7.05 (m,
/
H
m1 BCH2Ph), 7.00 (d, 1H, H3 ABA), 6.94 (t,
ꢃ
/
2
2
5.31 (d, Jꢀ
12.6 Hz, 1H, CHH? ABA), 3.25 (d, broad, Jꢀ
1H, BCHH?Ph), 2.62 (d, 2Jꢀ
11.4 Hz, 1H, ZrCHH?Ph),
2.55 (broad, 1H, BCHH?Ph), 2.54 (d, Jꢀ
/
12.6 Hz, 1H, CHH? ABA), 3.67 (d, Jꢀ
/
2
/
8.8 Hz,
7.61 (m, 4H, Ho SiPh), 6.90 (m, 8H, Hmꢃ
Ar ABA), 6.79 and 6.72 (dt, 1H, H4ꢃH5 ABA), 4.54 (s,
2H, CH2 ABA), 0.81 (s, 3H, SiMePh2), ꢁ0.12 (s, 9H,
SiMe3). 19F-NMR (C6D6, 376 MHz): d ꢁ
122.92 (d,
/Hp SiPh and
/
/
2
/
11.4 Hz, 1H,
0.01 (s, 9H,
/
ZrCHH?Ph), 0.29 (s, 9H, ArNSiMe3), ꢁ
/
/
3
CH2NSiMe3). Labeling follows Scheme 2. 13C-NMR
(CD2Cl2, 125 MHz, 183 K): d 156.94 (Cipso BCH2Ph),
3Jꢀ
Hz, Fp C6F5), ꢁ
Anal. Calc. for C35H28F10N2Si2Zr: C, 51.64; H,3.47; N,
/
18.6 Hz, 4F, Fo C6F5), ꢁ
/
155.83 (t, 2F, Jꢀ
/
19.5
3
/
164.40 (t, 4F, Jꢀ
/
18.6 Hz, Fm C6F5).
1
146.82 (d, JCF
1
ZrCH2Ph), 137.22 (d, JCF
ꢀ
/
235 Hz, Co C6F5), 145.80 (Cipso
246 Hz, Cp C6F5), 135.71
ꢀ
/
3.44. Found: C, 51.29; H, 3.44; N, 3.31%.
1
(d, JCF
ꢀ
/
247 Hz, Cm C6F5), 135.52 (C1 or C2 ABA),
135.30 (C1 or C2 ABA), 131.53, 131.27, 131.11, 130.25,
130.09, 129.89, 129.48 (CH Ar), 128.57 (2C, Co/m
ZrCH2Ph), 127.94, 127.88, 126.23 (CH Ar), 124.78
(2C, Co/m ZrCH2Ph), 123.71, 122.22 (CH Ar ABA),
122.04 (broad, Cipso C6F5), 73.17 (ZrCH2Ph), 51.98
(CH2 ABA), 34.35 (broad, BCH2Ph), 1.27 (SiMe3),
Acknowledgements
We thank the CNRS and the Ministe`re de l?Education
Nationale, de la Recherche et de la Technologie for
funding this work, the late Professor J.A. Osborn for his
support, and R. Graff (ULP, Strasbourg) for the
NOESY and ROESY measurements.
ꢁ1.39 (SiMe3).
/
4.3. [Zr(ABA2)(CH2Ph)][(h6-PhCH2)B(C6F5)3] (2)
A solution of 24 mg of Zr(ABA2)(CH2Ph)2 (0.036
mmol) in 0.4 ml of C7D8 was introduced into an NMR
tube. Addition of 18 mg of B(C6F5)3 (0.035 mmol) was
followed by instantaneous color change to deep orange.
NMR spectroscopy showed that 2 had formed in
References
[1] M. Bochmann, J. Chem. Soc. Dalton Trans. (1996) 255, and
references therein.
[2] (a) For more recent work on cationic zirconium-alkyl complexes
see: T. Cuenca, M. Galakhov, G. Jimenez, E. Royo, P. Royo, M.
Bochmann, J. Organomet. Chem. 543 (1997) 209;
1
quantitative yield. H-NMR (C7D8, 300 MHz): d 7.50
(m, 4H, Ho SiPh), 7.28 (m, 3H, Hmꢃ
/
Hp SiPhPh?), 7.16
(b) R. Baumann, W.M. Davis, R.R. Schrock, J. Am. Chem. Soc.