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R. Andres et al. / Journal of Organometallic Chemistry 690 (2005) 939–943
942
g, 0.060 mmol) in toluene (20 ml), and stirred for 8 h.
Subsequently, the solution was filtered and evaporated
in vacuo to dryness to yield 4-dend as a spectroscopically
pure, red oil (0.095 g, 85%). Anal. Calc. for
in agreement with those previously reported by Rahim
et al. [7].
4.7. Ethylene polymerisation
C
112H122N2O2Si8Cl2Ti: C, 71.87; H, 6.57; N, 1.50.
1
Found: C, 71.95; H, 6.60; N, 1.47%. H NMR (C6D6):
d 7.49 (m, 24H, SiC6H5), 7.18 (two multiplets overlap-
ping, 36H, SiC6H5), 6.80 (center of an AA0BB0 spin sys-
tem, 8H, C6H4), 6.25 (s, 5H, C5H5), 5.42 (s, 1H, CH),
1.68 (s, 6H, CH3CN), 1.10 and 0.92 (m, 24H, SiCH2H2
Si), 0.47 (s, 18H, SiCH3). 13C NMR (C6D6): d 161.4
(CH3CN) 154.2 (C6H4, C4), 148.3 (C6H4, C1 (carbon
linked to N)), 125.2 (broad, C6H4, C2,6) 120.1 (C6H4,
C3,5), 122.6 (C5H5), 99.9 (CH), 22.7 (C3 CNH), 129.6
(C6H5, C4), 137.0 (C6H5, C1 (carbon linked to Si)),
134.8 (C6H5, C2,6), 128.3 (C6H5, C3,5), 6.0 and 5.4
(SiCH2CH2Si), ꢀ4.8 (SiCH3). 29Si NMR (C6D6): d
19.9 (s, 2Si), ꢀ5.7 (s, 6Si).
A 250 ml flask charged with toluene (50 ml) and
equipped with a magnetic stirrer was four times evacu-
ated and refilled with pre-dried ethylene gas. Keeping
the flask pressurised with ethylene (1 bar) and stirred at
room temperature, a toluene solution of MAO, 0.83 ml,
1.5 M was syringed through a septum. After 5 min, a
toluene solution of the catalyst (0.50 ml, 2.5 mM) was
injected into the flask with simultaneous starting of a
stopwatch. The polymerization was quenched 20 min
later by closing the ethylene feeding, release of the over-
pressure and addition of acidified methanol (4% v/v
HCl). The mixture was stirred for 6H and the polymer
was filtered, washed with copious amounts of methanol,
and dried in an oven to constant weight.
5-dend (M = Zr). This complex was obtained as a
pale-yellow oil in 90% yield by a similar procedure of
that described in detail for 4-dend. Anal. Calc. for
C
112H122N2O2Si8Cl2Zr: C, 70.25; H, 6.42; N, 1.46.
Acknowledgements
1
Found: C, 70.45; H, 6.49; N, 1.43%. H NMR (C6D6):
d 7.48 (m, 24H, SiC6H5), 7.18 (two multiplets overlap-
ping, 36H, SiC6H5), 6.80 (center of an AA0BB0 spin sys-
tem, 8H, C6H4), 6.23 (s, 5H, C5H5), 5.22 (s, 1H, CH),
1.73 (s, 6H, CH3CN), 1.08 and 0.86 (m, 24H, SiCH2H2-
Si), 0.46 (s, 18H, SiCH3). 13C NMR (C6D6): d 164.2
(CH3CN) 154.1 (C6H4, C4), 144.1 (C6H4, C1 (carbon
linked to N)), 125.4 (C6H4, C2,6), 120.3 (C6H4, C3,5),
91.4 (CH), 22.3 (C3CN), 129.6 (C6H5, C4), 137.0
(C6H5, C1 (carbon linked to Si)), 134.8 (C6H5, C2,6),
128.2 (C6H5, C3,5), 117.3 (C5H5), 6.0 and 5.3
(SiCH2CH2Si), ꢀ4.9 (SiCH3). 29Si NMR (C6D6): d
19.8 (s, 2Si), ꢀ5.7 (s, 6Si).
We gratefully acknowledge financial support from the
´
y Tecnologıa (Project
DGI-Ministerio de Ciencia
´
BQU2001-1160 and FEDER-Programa Ramon y Cajal),
and Comunidad de Madrid (Project 07N/0078/2001).
References
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4 (M = Ti). Triethylamine (0.20 ml, 1.4 mmol) was
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0.80 mmol) and (g5-C5H5)TiCl3 (0.175 g, 0.80 mmol).
After stirring for 8 h, the solution was filtered. Toluene
was added to the solution until precipitation of a red so-
lid that was filtered and dried in vacuo to yield 4 (0.300
g, 86%). Anal. Calc. for C22H22N2Cl2Ti: C, 61.00; H,
G.E. Oosterom, J.N.H. Reek, P.C.J. Kamer, P.W.N.M. van
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´ ´
´
[3] R. Andres, E. de Jesus, F.J. de la Mata, J.C. Flores, R. Gomez,
1
5.12; N, 6.47. Found: C, 60.85; H, 5.10; N, 6.43%. H
NMR (C6D6): d 7.10 (m, 4H, C6H5), 6.92 (two multi-
plets overlapping, 6H, C6H5), 6.17 (s, 5H, C5H5), 5.33
(s, 1H, CH), 1.61 (s, 6H, CH3). 13C NMR (C6D6): d
161.3 (CH3CN) 154.4 (C6H5, C1 (carbon linked to N)),
129.0 (C6H5, C3,5), 126.4 (C6H5, C4), 124.0 (broad,
C6H5, C2,6), 122.6 ( C5H5), 99.9 (CH), 22.5 (CH3).
5 (M = Zr). Complex 5 was prepared by the same
procedure above described for 4, and obtained as a
pale-yellow solid in 90% yield. Spectroscopic data are
Eur. J. Inorg. Chem. (2002) 2281.
[4] Some authors state that 4-dend and 5-dend should not be
denominated as dendritic complexes if there is not a way to go
further in the generation of such compounds. We agree with this
observation. In fact, we have developed a simple procedure for
preparing ClSi(carbosilane) dendrons of higher generations that
should allow the synthesis of similar metal complexes of second
´
and higher generations. Andres et al. (manuscript in preparation).
[5] L. Bourget-Merie, M.F. Lappert, J.R. Seven, Chem. Rev. 102
(2002) 3031.