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T. Cuenca et al. / Journal of Organometallic Chemistry 588 (1999) 134–140
dichloromethane (250 ml) a clear yellow solution was
obtained. This solution was concentrated to 75 ml and
cooled at 0°C to give a pale yellow solid. Recrystalliza-
tion from toluene–hexane gave a yellow crystalline
solid characterized as 1 (13.65 g, 39.2 mmol, 51% yield).
C14H20HfSi: C, 42.58; H, 5.11. Found: C, 42.23; H,
5.06%. H-NMR (C6D6, 25°C, 300 MHz): l −0.20 (s,
6H, HfMe); 0.15 (s, 6H, SiMe2); 5.34 (t, JHꢀH=2.2 Hz,
4H, C5H4); 6.59 (t, JHꢀH=2.2 Hz, 4H, C5H4). 13C{1H}-
NMR (C6D6, 25°C, 75 MHz): l −5.5 (SiMe2); 36.3
(HfMe); 111. 5, 120.3 (s, C2ꢀC5), Cipso not observed.
1
3.2. Synthesis of [Hf{(SiMe2)(p5-C5H4)2}Cl2] (2)
3.5. Synthesis of
Toluene (100 ml) was added to a mixture of
[(SiMe2)(C5H4)2Li2] (0.98 g, 4.9 mmol) and hafnium
tetrachloride (1.57 g, 4.9 mmol) at r.t. and refluxed for
24 h. The reaction mixture was then allowed to cool
down to r.t. The toluene solution was filtered through
Celite and the solvent was completely removed in vacuo
to give a white crystalline solid. Recrystallization from
toluene–hexane at −20°C gave a solid characterized as
2 (1.85 g, 4.25 mmol, 87% yield). Anal. Calc. for
C12H14Cl2HfSi: C, 33.08; H, 3.24. Found: C, 33.25; H,
3.28%. 1H-NMR (C6D6, 25°C, 300 MHz): l 0.09 (s, 6H,
SiMe2); 5.41 (t, JHꢀH=2.2 Hz, 4H, C5H4); 6.69 (t,
[Zr{(SiMe2)(p5-C5H4)2}(CH2CMe2Ph)2] (5)
THF (100 ml) was added to
a mixture of
[Zr{(SiMe2)(h5-C5H4)2}Cl2] (1) (0.50 g, 1.43 mmol) and
LiCH2CMe2Ph (0.4 g, 2.86 mmol) at −78°C. The
reaction mixture was warmed to r.t. and stirred for 12
h. The solvent was completely removed in vacuo to give
a solid, which was extracted with hexane (100 ml) to
obtain a yellow solution. This solution was concen-
trated to 25 ml and cooled at 0°C to give a pale yellow
solid. Recrystallization from toluene–hexane gave a
yellow crystalline solid characterized as 5 (0.43 g, 0.8
mmol, 56% yield). Anal. Calc. for C32H40SiZr: C, 69.30;
J
HꢀH=2.2 Hz, 4H, C5H4). 13C{1H}-NMR (C6D6, 25°C,
1
75 MHz): l −6.2 (SiMe2); 111.1, 126.5 (s, C2ꢀC5);
(Cipso not observed).
H, 7.75. Found: C, 69.57; H, 7.43%. H-NMR (C6D6,
25°C, 300 MHz): l 0.15 (s, 6H, SiMe2); 0.99 (s, 4H,
ZrCH2); 1.39 (s, 12H, CMe2); 5.31 (m, 4H, C5H4); 6.41
(m, 4H, C5H4); 7.13 (m, 2H, Ph); 7.25 (m, 4H, Ph); 7.36
(m, 4H, Ph). 13C{1H}-NMR (C6D6, 25°C, 75 MHz): l
3.3. Synthesis of [Zr{(SiMe2)(p5-C5H4)2}(CH3)2] (3)
A 0.95 ml (2.86 mmol) sample of a chloromethyl
magnesium 3 M solution in THF was added, at −
78°C, to a solution of [Zr{(SiMe2)(h5-C5H4)2}Cl2] (1)
(0.5 g, 1.43 mmol) in hexane (75 ml). The reaction
mixture was warmed to r.t. and stirred for 12 h. The
solution was filtered through Celite and the solvents
were completely removed in vacuo to yield a white
solid. Recrystallization from toluene–hexane at −20°C
gave a microcrystalline white solid characterized as 3
(0.20 g, 0.65 mmol, 45% yield). Anal. Calc. for
C14H20SiZr: C, 54.67; H, 6.51. Found: C, 54.80; H,
−5.5 (SiMe2); 34.8 (CMe2); 43.9 (C6 Me2); 75.4 (ZrCH2);
101.8 (Cipso); 112.6, 119.4 (s, C2ꢀC5); 125.4, 125.9, 153.6
(Ph).
3.6. Synthesis of
[Hf{(SiMe2)(p5-C5H4)2}(CH2CMe2Ph)2] (6)
Diethyl ether (60 ml) was added to a mixture of
[Hf{(SiMe2)(h5-C5H4)2}Cl2] (2) (0.30 g, 0.70 mmol) and
LiCH2CMe2Ph (0.19 g, 1.35 mmol) at −78°C. The
reaction mixture, which immediately turned cloudy due
to the precipitation of LiCl, was stirred for 6 h at r.t.
The solution was filtered and the solvent removed in
vacuo to give a white solid. Recrystallization from
toluene–hexane at −20°C gave a microcrystalline
white solid characterized as 6 (0.38 g, 0.60 mmol, 86%
yield). Anal. Calc. for C32H40HfSi: C, 60.89; H, 6.39.
1
6.26%. H-NMR (C6D6, 25°C, 300 MHz): l −0.03 (s,
6H, SiMe2); 0.13 (s, 6H, ZrMe); 5.41 (m, 4H, C5H4);
6.68 (m, 4H, C5H4). 13C{1H}-NMR (C6D6, 25°C, 75
MHz): l −5.4 (SiMe2); 20.3 (ZrMe); 101.3 (Cipso);
112.4, 120.9 (s, C2ꢀC5).
3.4. Synthesis of [Hf{(SiMe2)(p5-C5H4)2}(CH3)2] (4)
Found: C, 60.83; H, 6.26%. H-NMR (C6D6, 25°C, 300
1
MHz): l 0.16 (s, 6H, SiMe2); 0.74 (s, 4H, HfCH2); 1.40
(s, 12H, CMe2); 5.22 (t, 4H, C5H4); 6.37 (t, 4H, C5H4),
7.10–7.35 (m, 10H, Ph).
A 0.32 ml (0.96 mmol) sample of a chloromethyl
magnesium 3 M solution in THF was added, at −
78°C, to a solution of [Hf{(SiMe2)(h5-C5H4)2}Cl2] (2)
(0.21 g, 0.48 mmol) in diethyl ether (50 ml). The
reaction mixture was stirred for 2 h at low temperature
and after 16 h at r.t. a white precipitate was formed.
The solution was filtered through Celite and the sol-
vents were completely removed in vacuo to yield a
white solid. Recrystallization from toluene–hexane at
−20°C gave a microcrystalline white solid character-
ized as 4 (0.18 g, 0.45 mmol, 94% yield). Anal. Calc. for
3.7. Synthesis of [Zr{(SiMe2)(p5-C5H4)2}(CH2Ph)2] (7)
THF (100 ml) was added to
a mixture of
[Zr{(SiMe2)(h5-C5H4)2}Cl2] (1) (0.50 g, 1.43 mmol) and
Mg(CH2Ph)2(THF)2 (0.52 g, 1.44 mmol) at −78°C.
The reaction mixture was warmed to r.t. and stirred for
12 h. The solvent was completely removed in vacuo to
give a solid, which was extracted with hexane (100 ml)
Cuenca, Tomas
