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dried over sodium/benzophenone under nitrogen and were
freshly distilled prior to use. CH2Cl2 and n-hexane were
refluxed under nitrogen over calcium hydride and distilled
before use. Methylaluminoxane (MAO, 10 wt.% solution
in toluene, M = 800 g molꢀ1, Al = 5.3 wt.%) was pur-
chased from Wtico. Al(iBu)3, methyl lithium, n-butyl lith-
ium and titanium tetrachloride were purchased from
Aldrich. 1,2-Diphenyl-4-methyl-cyclopentadienyl titanium
trichloride (1), 1,2-diphenyl-4-n-butyl-cyclopentadienyl
titanium trichloride (2) [21] and Ph3C+B(C6F5)ꢀ [23–25]
were prepared according to the literature procedures. The
crystal structure was determined with a CCD diffraction
apparatus. NMR spectra were measured using a Varian
Mercury-300 NMR spectrometer. Elemental analyses were
performed on a Perkin–Elmer 240c element analyzer. Vis-
cosity-average molecular weights of the polyethylenes were
determined in decahydronaphthalene at 135 ꢁC using a
Schott Gerate Mod. AVS/T2 Ubbelohde viscosimeter. Vis-
cosity-average molecular weights of the polystyrenes were
determined in o-dichlorobenzene at 135 ꢁC using a Schott
Gerate Mod. AVS/T2 Ubbelohde viscosimeter. Melting
transition temperatures (Tm) of the polyethylenes and poly-
styrenes were determined by DSC (Du Pont 910 differential
2.3. Synthesis of (1,2-Ph2-4-n-Bu-CpTiCl2)2(l-O) (4)
Compound 4 was prepared in the same manner as
described above for the synthesis of 3 (Scheme 1), and iso-
lated in 89.2% as a red crystalline solid. Anal. Calc. for
C42H42Cl4OTi2 (800.36): C, 63.03; H, 5.29. Found: C,
1
63.05; H, 5.21%. H NMR (CDCl3, 300 MHz, 298 K): d
3
3
0.91 (t, JHH = 7.7 Hz, 6H, CH3), 1.35 (m, JHH = 7.5 Hz,
3
4H, CH2), 1.60 (m, JHH = 7.6 Hz, 4H, CH2), 2.73 (t,
3JHH = 7.8 Hz, 4H, CH2), 6.88 (s, 4H, C5H2), 7.27–7.50
(m, 20H, C6H5). 13C NMR (CDCl3, 75 MHz, 298 K): d
14.1, 22.6, 31.4, 32.7 (C4H9), 128.9, 133.4, 143.3 (C5H2),
122.3, 128.4, 129.8, 136.1 (C6H5).
2.4. X-ray structure determination of 3 and 4
Crystals of 3 and 4 suitable for X-ray structure determi-
nation were obtained from a saturated solution of CH2Cl2/
n-hexane (1:5, v/v) at room temperature. Diffraction data
were collected at 293 K on a Bruker SMART-CCD diffrac-
tometer using Mo Ka radiation. The structures were solved
using direct methods and refined by full-matrix least-
squares procedures [26]. All non-hydrogen atoms were
refined anisotropically and the hydrogen atoms were
included in ideal positions. All calculations were performed
using the SHELXTL crystallographic software packages [27].
Relevant crystallographic data are summarized in Table 1.
scanning calorimeter) at a heating rate of 10 ꢁC minꢀ1
.
2.2. Synthesis of (1,2-Ph2-4-Me-CpTiCl2)2(l-O) (3)
A mixture of Et2O (20 mL) and distilled H2O (9.0 lL,
0.50 mmol) was slowly added at ꢀ15 ꢁC to solid complex
1 (385.5 mg, 1.00 mmol), and the obtained solution was
warmed to room temperature and stirred for 48 h (Scheme
1). The solvent was removed in vacuo, and the resulting res-
idue was extracted with a mixed solvent of CH2Cl2/n-hex-
ane (1:3, 15 · 2 mL). The solution was concentrated to give
a red solid (317.3 mg, 88.6%). Red crystals of the complex
suitable for X-ray diffraction were obtained by recrystalli-
zation from a mixture of CH2Cl2/n-hexane (1:5) at room
temperature. Anal. Calc. for C36H30Cl4OTi2 (716.20): C,
60.37; H, 4.22. Found: C, 60.31; H, 4.18%. 1H NMR
(CDCl3, 300 MHz, 298 K): d 2.40 (s, 6H, CH3), 6.87 (s,
4H, C5H2), 7.28–7.50 (m, 20H, C6H5). 13C NMR (CDCl3,
75 MHz, 298 K): d 17.2 (CH3), 128.9, 133.4, 137.9 (C5H2),
123.2, 128.4, 129.7, 136.3 (C6H5).
2.5. Polymerization of ethylene
The ethylene polymerizations (runs 1–8) were carried
out according to the following procedure: A dry 250 mL
steel autoclave with a magnetic stirrer was charged with
70 mL of toluene, thermostated at the desired temperature
and saturated with ethylene (1.5 bar). The polymerization
reaction was initiated by addition of a mixture solution
of precatalyst and Al(iBu)3 in toluene (5 mL) and a solu-
tion of Ph3CþBðC6F5Þ in toluene (5 mL) at the same
ꢀ
4
time. The gaseous ethylene was then admitted into the reac-
tor vessel through a gas purification column. The gas pres-
sure was maintained at 6 bar throughout the
polymerization period by means of a pressure manometer.
After 15 min, the polymerization was quenched by addition
of 120 mL of 1:1 (v/v) methanol and HCl solution. The
white polymer was collected by filtration, washed several
times with water, methanol, and dried to a constant weight
under vacuum.
Ph
2.6. Polymerization of styrene
Ph
Ph
Cl
R
R
Ph
H2O
Cl
O
Ti
Cl
Ti
The styrene polymerizations (runs 1–10) with complexes
3 and 4 were carried out according to the following proce-
dure: A 250 mL Schlenk flask with a magnetic stirrer was
attached to high vacuum line and then sealed under a nitro-
gen atmosphere. Fifty milliliters of toluene, 5 mL of freshly
distilled styrene and an appropriate amount of MAO were
added to the flask which was placed in an oil bath at the
R
Cl
Ti
Cl
Cl
Ph
Cl
Ph
1 R = Me
2 R = n-Bu
3 R = Me
4 R = n-Bu
Scheme 1. Synthetic procedure of complexes 3–4.