Ti and Zr Half-Sandwich Complexes
Organometallics, Vol. 16, No. 23, 1997 5005
{2-(C6F 5)(Me2N)B(In d )}Zr Cl3 (13). To a solution of 11
(4.18 g, 7.47 mmol) in toluene (20 mL) at -30 °C was added
SiClMe3 (7.3 g, 5.8 mL, 67.2 mmol) slowly via syringe. The
reaction was warmed to room temperature and stirred for 6
h. Removal of the solvents gave 13 as a yellow foam, yield
90% by NMR.
[productivity 2.4 × 103 g PE (mol of Ti‚bar‚h)-1]. Under
comparable conditions, no polymer was obtained from 50 to
250 µmol of CpTiCl3. Simlarly, a solution of 14 (50 µmol) and
AlEt3 (250 µmol) in toluene (20 mL) was stirred under 1 bar
ethene at 20 °C for 1 h, resulting in the recovery of 0.163 g of
PE. An identical comparison experiment using IndZrCl3/AlEt3
at 20 °C gave only a faint trace of polymer.
NMR Rea ction of 18 w ith AlMe3. In an NMR tube, 0.41
mL of a 0.15 M solution of 18 (0.06 mmol) in toluene-d8 was
cooled to -78 °C. A 1.5 M solution of AlMe3 (0.2 mL, 0.3 mmol)
was then added via syringe. The solutions were mixed, and
the sample was inserted into the spectrometer at -50 °C. At
-20 °C, the formation of {C5H4B(C6F5)2}TiMe2Cl (19) was
evident as the only identifiable titanium species, together with
a broad signal for excess AlMe3 and AlMe2Cl. 1H NMR of 19
(300 MHz, toluene-d8): δ 6.29 (t, 2 H, J ) 2.31 Hz, 2,5-CpB),
6.03 (t, 2 H, J ) 2.3 Hz, 3,4-CpB), 1.32 (s, 6 H, TiMe). 13C
NMR (75.47 MHz, toluene-d8): δ 148.30 (d, J CF ) 233 Hz,
{1-(C6F 5)(Me2N)B(In d )}Zr Cl3 (14). To a solution of 12
(4.90 g, 8.76 mmol) in 20 mL of toluene and was added SiClMe3
(8.56 g, 6.81 mL, 78.8 mmol). The mixture lightened in color
and became slightly warm. The solution was stirred for 6 h
before the solvent was stripped off to give a golden yellow foam.
The crude yield was ca. 90% by NMR. The crude material
readily dissolved in CH2Cl2 from which a microcrystalline solid
precipitated on standing at room temperature. 19F NMR
(THF-d8, 20 °C): δ -130.2 (m, 1 F, o-F), -131.3 (m, 1 F, o-F),
-154.7 (m, 1 F, p-F), -164.0 (m, 2 F, m-F). Anal. Calcd for
C
17H12BCl3F5NZr: C, 39.42; H, 1.73; N, 2.00; F, 27.11; Cl,
15.18. Found: C, 38.2; H, 2.6; N, 2.2; F, 28.5; Cl, 17.85. MS
(EI): m/ z 533 (M+), 336 [C9H6B(C6F5)(NMe2)+], 291 [C9H6B-
(C6F5)+], 114 (C9H7+), 163 (ZrCl2+).
m-C6F5), 140.10 (d, J CF ) 244 Hz, p-C6F5), 136.44 (d, J CF
)
226 Hz, o-C6F5), 121.59 (2,5-CpB), 119.60 (3,4-CpB), 71.42 (Ti-
Me). 11B NMR: δ 72.52.
{2-(C6F 5)(Me2N)B(In d )}Zr Cl3‚DME (15). To a suspension
of 13 (3.73 g, 7.0 mmol) in petroleum (30 mL) was added
dimethoxyethane (0.63 g, 0.73 mL, 7.0 mmol). After stirring
for 4 h, a pale yellow powder had precipitated. Filtration and
drying in vacuo at 20 °C for 6 h afforded 15 (4.0 g, 6.41 mmol,
92%). Anal. Calcd for C21H22BCl3F5NO2Zr: C, 40.44; H, 3.56;
N, 2.25; Cl, 17.05. Found: C, 39.55; H, 3.80; N, 2.20; Cl, 18.75.
{1-(C6F 5)(Me2N)B(In d )}Zr Cl3‚2THF (16). Compound 14
(3.73 g, 7.0 mmol) was dissolved in THF (3 mL) and the excess
THF removed under vacuum. The resulting foam was recrys-
tallized from a CH2Cl2/petroleum mixture at -16 °C, yielding
bright yellow needle cushions (2.0 g, 2.95 mmol, 42%). Anal.
Calcd for C25H28BCl3F5NO2Zr: C, 44.30; H, 4.16; N, 2.07; Cl,
15.69. Found: C, 44.05; H, 4.5; N, 1.90; Cl, 17.8.
(C6F 5)2B(C5H4SiMe3) (17). Following the procedure de-
scribed for 4, a solution of 1 in Et2O (200 mL, 1.0 M, 0.2 mol)
was treated with Li[C5H4SiMe3]. Removal of the volatiles left
a golden brown foam which was extracted with petroleum (500
mL) to give a red solution. Removal of the solvent left 17 as
a red-brown oil which slowly crystallized at 5 °C (55 g, 114
mmol, 57%). Anal. Calcd for C20H13BF10Si: C, 49.82; H, 2.72.
Found: C, 49.45; H, 2.65.
X-r a y Cr ysta llogr a p h y. Data for all three complexes were
collected at 160 K on a Stoe STADI4 diffractometer operating
in the ω-θ scan mode. All three compounds were corrected
for absorption empirically using azimuthal ψ-scans. Full
details of crystal data, data collection, and structure refine-
ment are given in Table 2.
The structures of all three compounds were solved by
standard heavy-atom methods using SHELXS-86.33 The
asymmetric unit of 9 was found to contain a half molecule of
toluene disordered across the center of symmetry at (-2 - x,
-y, 1 - z). Refinement, by full-matrix least squares on F2
using SHELXL-93,34 was essentially the same for all three
compounds. Non-hydrogen atoms (including those of the
toluene solvate molecule of 9) were refined with anisotropic
displacement parameters. Hydrogen atoms were constrained
to idealized positions using a riding model (with free rotation
for methyl groups).
Complete atomic coordinates, anisotropic displacement pa-
rameters, and interatomic distances and angles have been
deposited with the Cambridge Crystallographic Data Centre.
See Instructions for Authors, Organometallics, 1997, Issue 1.
{C5H4B(C6F 5)2}TiCl3 (18). To an orange solution of 17
(3.26 g, 6.76 mmol) in CH2Cl2 (40 mL) at -78 °C was added
TiCl4 (1.52 g, 0.88 mL, 8 mmol) via syringe. The reaction was
allowed to warm to room temperature and stirred for 72 h.
The color changed to green with a small amount of dark
precipitate which was filtered off. The filtrate was concentrated
to ca. 10 mL and left to crystallize at -20 °C overnight.
Yellow-orange crystals of 18 formed (2.8 g, 4.97 mmol, 73.5%).
X-ray quality crystals were grown from a CH2Cl2/petroleum
solution at 5 °C. Anal. Calcd for C17H4BCl3F10Ti: C, 36.25;
H, 0.72; Cl, 18.88. Found: C, 36.10; H, 0.85; Cl, 18.75.
P olym er iza tion s. Ethene polymerization were carried out
by saturating toluene (20 mL) with ethene (1 bar) at -20 °C.
AlEt3 (250 µmol) was injected, followed by 50 µmol of 18 in
toluene (0.5 mL). The reaction was stopped by the injection
of methanol (2 mL) after 1 h, giving 0.12 g of polyethene
Ack n ow led gm en t. This work was supported by BP
Chemicals, Sunbury. We thank Mr. P. Howard, Dr. P.
Bre`s, and Dr. B. Dorer for helpful discussions. R.D.
thanks the Netherlands Organization for Scientific
Research (NWO) for a research fellowship.
Su p p or tin g In for m a tion Ava ila ble: Tables of full crys-
tallographic data for 1, 9, and 18 (9 pages). Ordering informa-
tion is given on any current masthead page.
OM970433J
(33) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467-473.
(34) Sheldrick, G. M. SHELXL 93, Program for refinement of crystal
structures, University of Go¨ttingen, 1993.