Macromolecules
ARTICLE
8.11(1H, d, J = 5.5 Hz, oPyAr). δC (100 MHz, C6D6, 293 K, Me4Si): 18.7
(CH3), 43.21 (N(CH3)2), 62.58 (CH2), 120.95, 121.38, 123.18, 134.33,
136.78, 147.71, 152.58, 164.51 (Ar-C).
Anal. Found: C, 55.07; H,7.59; N, 16.12. Calcd for C20H33N5Zr: C,
55.26; H, 7.65; N, 16.11.
Synthesis of 2a. The reaction was performed as above, reacting 0.276
g of ligand 2 (1.0 mmol) and tetrakis(dimethylamido)titanium
(0.243 mL, 1.0 mmol) in 15 mL of hexane (yield: 0.400 g, 89%).
δH (400 MHz, C6D6, 293 K, Me4Si): 1.39 (6H, d, J = 6.7 Hz, -
CH(CH3)2), 1.55 (6H, d, J = 6.7 Hz, -CH(CH3)2), 3.04 (6H, s, -
N(CH3)2), 3.25 (12H, s, -N(CH3)2), 3.76 (2H, m, CH(CH3)2), 4.95
(2H, s, -CH2), 6.58-7.35 (6H, m, ArH), 8.00 (1H, d, J = 5.1 Hz, o-
PyAr). δC (100 MHz, CDCl3, 293 K, Me4Si): 24.11, 27.36 (CH3), 27.76
(CH), 46.30, 48.20 (N(CH3)2), 67.06 (CH2), 120.46, 121.60, 122.92,
123.22, 136.62, 144.34, 147.51, 162.91 (Ar-C).
poured into acidified ethanol. The polymers were washed with fresh
ethanol, recovered by filtration, and dried at 40 °C in a vacuum oven.
R-Olefin Polymerization. Ethylene and propylene polymerizations
were performed into a 500 mL B€uchi glass autoclave. The reactor vessels
were charged sequentially with MAO and a toluene solution of
precatalyst in toluene (2 mL), preaged for 10 min with a solution of
AliBu2H in toluene. The mixture was thermostated at the required
temperature and the monomer gas feed was started. In all cases, after the
required polymerization time the mixture was poured into acidified
ethanol. The polymers were recovered by filtration, and dried at 40 °C in
a vacuum oven.
X-ray Crystallography. Suitable crystals were selected and mounted
on a cryoloop with paratone oil and measured at 100 K with a Rigaku
AFC7S diffractometer equipped with a Mercury2 CCD detector
using graphite monochromated Mo KR radiation (λ = 0.71069 Å).
Data reduction was performed with the crystallographic package
CrystalClear.44 Data have been corrected for Lorentz, polarization,
and absorption. The structure was solved by direct methods using the
program SIR200245 and refined by means of full matrix least-squares
based on F2 using the program SHELXL97.46 For all compounds non-
hydrogen atoms were refined anisotropically, hydrogen atoms were
positioned geometrically and included in structure factors calculations
but not refined. Crystal data and refinement details are reported in Table
2S of the Supporting Information. Crystal structures were drawn using
ORTEP32.47
Anal. Found: C, 64.36; H,9.14; N, 15.58. Calcd for C24H41N5Ti: C,
64.42; H, 9.24; N, 15.65.
Synthesis of 2b. The reaction was performed as above, reacting 0.250
g of ligand 2 (0.9 mmol) and tetrakis(dimethylamido)zirconium (0.248
g, 0.9 mmol) in 15 mL of benzene (yield: 0.425 g, 96%).
δH (400 MHz, C6D6, 293 K, Me4Si): 1.44 (6H, d, J = 6.9 Hz, -
CH(CH3)2), 1.60 (6H, d, J = 6.9 Hz, -CH(CH3)2), 3.10 (18H, br s, -
N(CH3)2), 3.77 (2H, m, CH(CH3)2), 4.85 (2H, s, -CH2), 6.60 (2H,
m, ArH), 6.94 (1H, t, J = 7.7 Hz, ArH), 7.28 -7.38 (3H, m, ArH), 8.25
(1H, d, J = 5.5 Hz, o-PyAr). δC (100 MHz, CDCl3, 293 K, Me4Si) 24.03,
27.12 (CH3), 27.62 (CH), 39.93, 43.44 (N(CH3)2), 65.43 (CH2),
121.67, 122.37, 123.74, 125.24, 138.45, 147.93, 163.57 (Ar-C).
Anal. Found: C, 58.67; H,8.35; N, 14.08. Calcd for C24H41N5Zr: C,
58.73; H, 8.42; N, 14.27.
Synthesis of 3a. The reaction was performed as above, reacting 0.350
g of ligand 3 (1.76 mmol) and tetrakis(dimethylamido)titanium
(0.427 mL, 1.76 mmol) in 20 mL of benzene (yield: 0.550 g, 68%).
δH (400 MHz, CD2Cl2, 293 K, Me4Si): 1.14 (6H, d, J = 6.8 Hz, -
CH(CH3)2), 1.1.27 (6H, d, J = 6.8 Hz, -CH(CH3)2), 2.35 (3H, s,
PyCH3), 2.61 (6H, s, -N(CH3)2), 3.04 (12H, s, -N(CH3)2), 3.41 (2H,
m, CH(CH3)2), 4.79 (2H, s, -PyCH2), 6.93-7.68 (6H, m, ArH). δC
(100 MHz, CDCl3, 293 K, Me4Si): 23.81, 24.68, 27.11 (CH3), 27.89
(CH), 43.43, 44.03 (N(CH3)2), 56.70 (CH2), 117.47, 117.83, 118.94,
123.77, 137.07, 142.67, 146.73, 153.36 (Ar-C).
’ ASSOCIATED CONTENT
S
Supporting Information. X-ray crystallographic infor-
b
mation files in CIF format, selected bond distances and bond
angles, crystal data, and refinement details for compounds 1a, 2a,
and 2b and 13C NMR data for samples II and V of Table 3. This
acs.org.
’ AUTHOR INFORMATION
Corresponding Author
*Fax: þ39 089 969603. Telephone:þ39 089 969580.
Anal. Found: C, 64.98; H,9.25; N, 15.03. Calcd for C25H43N5Ti: C,
65.06; H, 9.39; N, 15.17.
’ ACKNOWLEDGMENT
Synthesis of (3b). The reaction was performed as above, reacting
0.500 g of ligand 3 (1.7 mmol) and tetrakis(dimethylamido)zirconium
(0.472 g, 1.7 mmol) in 20 mL of benzene (yield: 0.840 g, 97%).
δH (400 MHz, C6D6, 293 K, Me4Si): 1.30 (6H, d, J = 6.8 Hz, -
CH(CH3)2), 1.47 (6H, d, J = 6.8 Hz, -CH(CH3)2), 2.29 (3H, s,
PyCH3), 2.84 (6H, s, -N(CH3)2), 2.96 (12H, s, -N(CH3)2), 3.68
(2H, m, CH(CH3)2), 4.77 (2H, s, -CH2), 6.42 (1H, d, J = 7.7 Hz, ArH),
6.49 (1H, d, J = 7.6 Hz, ArH), 6.83 (1H, t, J = 7.6 Hz, ArH), 7.1-7.27
(3H, m, ArH). δC (100 MHz, CDCl3, 293 K, Me4Si): 22.21, 24.11, 27.07
(CH3), 28.12 (CH), 42.57, 44.38 (N(CH3)2), 65.66 (CH2), 118.22,
122.49, 123.19, 123.50, 137.41, 145.28, 149.93, 15911, 163.77 (Ar-C).
Anal. Found: C, 59.39; H,8.55; N, 13.59. Calcd for C25H43N5Zr: C,
59.47; H, 8.58; N, 13.87.
Polymerizations. 1,3-Butadiene Polymerization. Polymeriza-
tions of 1,3-butadiene were performed by introducing toluene
(50 mL) and MAO (580 mg, 1 ꢀ 10-2 mol) into 100-ml glass flasks
equipped with magnetic stirrer. The inert gas was evacuated, the
solutions were cooled with liquid nitrogen, and 1,3-butadiene (2,8 g,
0.052 mol) was assimilated into the flask. Then, the reactors were
quickly thermostated at 25 °C, the nitrogen inert atmosphere was
replaced and the precatalyst (10 μmol) in toluene (2 mL) preaged for
10 min with a toluene solution (1 mL, 0.28M) of AliBu2H. was injected.
After the required polymerization time (80 min), the mixture was
The authors are grateful to Dr. Patrizia Oliva, Dr. Patrizia
Iannece, Dr. Ivano Immediata and Dr. Mariagrazia Napoli for
technical assistance. This work was supported by the Italian
Ministry of University and Research (PRIN 2008). X-ray diffrac-
tion and NMR instrumentation was funded by the University of
Salerno “Finanziamento Grandi e medie attrezzature 2004”.
’ REFERENCES
(1) Porri, L.; Giarrusso, A. In Comprehensive Polymer Science; Perga-
mon Press: Oxford, U.K., 1989; Vol. 4, p 53.
(2) Thiele, S. K. H.; Wilson, D. R. J. Macromol. Sci., Polym Rev. 2003,
43, 581–628.
(3) Hou, Z.; Wakatsuki, Y. Coord. Chem. Rev. 2002, 231, 1–22.
(4) Zeimentz, P. M.; Arndt., S.; Eldvidge, B. R.; Okuda, J. Chem. Rev.
2006, 106, 2404–2433.
(5) Zhang, L.; Suzuki, T.; Luo, Y.; Nishiura, M.; Hou, Z. Angew.
Chem., Int. Ed. 2007, 46, 1909–1931.
(6) Gao, W.; Cui, D. J. Am. Chem. Soc. 2008, 130, 4984–4991.
(7) Ricci, G.; Forni, A.; Boglia, A.; Sommazzi, A.; Masi, F.
J. Organomet. Chem. 2005, 690, 1845–1854.
(8) Boisson, C.; Monteil, V.; Ribour, D.; Spitz, R.; Barbotin, F.
Macromol. Chem. Phys. 2003, 204, 1747–1754.
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dx.doi.org/10.1021/ma1028455 |Macromolecules 2011, 44, 1934–1941