S.S. Al-Juaid et al. / Journal of Organometallic Chemistry 631 (2001) 76–86
85
with benzene, and the extract filtered. The solvent was
removed from the filtrate to give a sticky solid, which
was shown by 1H-NMR spectroscopy to consist of
C(SiMe3)4 (23%), CH(SiMe3)3 (44%), and unchanged 10
(32%).
CSi3), 9.4 (CH2), 14.6 (CH3), 25.1 (THF), 32.6 and 33.8
(CH2), 40.4 (NMe2), 69.3 (THF). l (Si): −7.6 (SiMe3),
15.1 (SiMe2).
3.8. Crystallography
A solution of [Li(THF)4][Li{C(SiMe3)3}2] (0.75 g,
0.98 mmol) in Et2O (29 cm3) was added to a stirred
solution of 10 (2.0 mmol) in Et2O (12cm3). After 30 min
the solvent was removed from the mixture, the residue
extracted with toluene, and the extract filtered. The
sticky solid obtained after removal of the toluene from
the extract was shown by NMR spectroscopy to con-
tain Mg{C(SiMe3)3}2 (13%), CH(SiMe3)3 (29%), as well
as unidentified products, unchanged [Li(THF)4]-
[Li{C(SiMe3)3}2] and 10.
Data for 1, 4, 6, 10, 11 and 13 were recorded on a
CAD4 and for 8 on a Kappa CCD diffractometer by
,
use of Mo–Ka radiation (u=0.71073 A). Further de-
tails are given in Table 2. Structural analysis was by
direct methods (SHELXS-86 or SHELXS-97) and refine-
ment by full least-squares on all data (SHELXL-93 or
SHELXL-97). Non-H atoms were anisotropic and H
atoms were included in riding mode. In 4, there are two
molecules of occluded benzene in the asymmetric unit;
the high R factors result from the weak high angle
diffraction. In 10 there is a molecule of toluene disor-
dered across an inversion centre and the H atoms in
this were omitted.
3.6. [Mg{C(SiMe3)2(SiMe2Ph)}I(OEt2)]2 (11)
Magnesium turnings (0.24 g, 10 mmol) were acti-
vated as above, then Et2O (20 cm3) and a crystal of
iodine were added. A solution of (Me3Si)2(PhMe2Si)CI
[32] (2.1 g., 5.0 mmol) in Et2O (20 cm3) was added
dropwise and the mixture stirred for 1 h. The precipi-
tated solids were filtered off and extracted with toluene
(2×10 cm3) at 50 °C and the extract left at r.t. to give
colourless crystals of 11 (0.69 g, 31%). The Et2O was
pumped from the filtrate to leave a sticky solid, which
was shaken with hexanes (20 cm3) and washed with
heptane at −50 °C to leave a white powder that
4. Supplementary material
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Center, CCDC nos. 162000–162006 for com-
pounds 1, 4·2C6H6, 6, 8, 10·C6H5CH3, 11 and 13,
respectively. Copies of this information may be ob-
tained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (Fax: +44-
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
1
showed the same H-NMR spectrum as the crystals. l
(H): 0.48 (18H, s, SiMe3), 0.69 (6H, s, SiMe2), 0.74 (6H,
t) and 3.41 (4H, q, Et2O), 7.25 (3H, m, m- and p-H),
7.91 (2H, d, o-H). l (C): 2.7 (CSi3), 3.4 (SiMe3), 7.9
(SiMe2), 15.3 and 65.8 (Et2O), 125.6, 129.3, 135.8 and
142.5 (Ph). l (Si): −9.6 (SiMe2), −6. 0 (SiMe3). m/z:
429 (20%, [M]−Me−THF), 279 [100, CH(SiMe3)2-
(SiMe2Ph)−Me].
Acknowledgements
We thank the EPSRC and the EU for financial
support and the Governments of Saudi Arabia and
Libya, respectively, for granting study leave to S.S.Al-J.
and S.M.El-H.
¸¹¹¹¹¹¹¹¹¹¹¹¹¹º
3.7. [MgBu{C(SiMe3)2(SiMe2NMe2)}(THF)] (13)
A solution of LiBu (8.7 mmol) in hexanes (3.5 cm3)
was added dropwise to
a
stirred solution of
(Me3Si)2(Me2NMe2Si)CCl (1.86 g, 6.31 mmol) [2] in
THF (40 cm3) at −78 °C. The mixture was stirred for
2 h and then added dropwise to a stirred solution of
[MgBr2(OEt2)2] (0.79 g, 2.40 mmol) in THF (20 cm3) at
−120 °C. The mixture was allowed to warm to r.t. and
the solvent was pumped away to leave a sticky brown
residue, which was extracted with hexanes. The extract
was concentrated to 15 cm3, then kept at −30 °C to
give yellow crystals of 13 (0.95 g, 95% based on
MgBr2), m.p. 147–154 °C. l (H): −0.13 (2H, t,
CH2Mg), 0.29 (6H, s, SiMe2), 0.41 (18H, s, SiMe3),
1.19–1.23 (7H, m, THF and CH3), 1.66 and 1.76 (2H,
m, CH2), 2.09 (6H, s, NMe2), 3.42 (4H, m, THF). l
(C): 3.5 (SiMe2), 8.1 (SiMe3), 8.7 (1JCSi=41.5 Hz,
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