Article pubs.acs.org/Organometallics
Isoprene Polymerization with Iminophosphonamide Rare-EarthMetal Alkyl Complexes: Influence of Metal Size on the Regio- and Stereoselectivity Bo Liu,†,‡ Guangping Sun,‡ Shihui Li,*,† Dongtao Liu,*,† and Dongmei Cui*,† †
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China ‡ Key Laboratory of Automobile Materials of Ministry of Education, Department of Materials Science and Engineering, Jilin University, Changchun, 130025, China S Supporting Information *
ABSTRACT: The protonolysis reaction of β-iminophosphonamine ligand (NPNdipp = Ph2P(NC6H3iPr2-2,6)2) with one equivalent of rare-earth-metal tris(alkyl)s afforded the c orresponding bis(alkyl) complexes NPN d i p p Ln(CH2SiMe3)2(THF) (Ln = Sc (1), Lu (2), Y (3), Er (4)). The bis(4-methylbenzyl) complexes NPNdippLn(CH2Ph-4Me)2(THF) (Ln = Nd (5), La (6)) were prepared by treatment of the tris(4-methylbenzyl) compounds Ln(CH2Ph4-Me)3(THF)3 with β-iminophosphonamine ligand. The small-size rare-earth-metal-based complexes 1−4 upon activation with AliBu3 and [Ph3C][B(C6F5)4] showed high 3,4-selectivities up to 98.1% for isoprene polymerization. When the larger size rareearth-metal-based 4-methylbenzyl complexes 5 and 6 were employed instead, moderate 3,4-selectivities were obtained since the opening coordination environment facilitated the 1,4-enchainment (Nd3+: 76.1%; La3+: 62.9%). Replacing AliBu3 by AlEt3, the 5 and 6 systems exhibited high activity and excellent trans-1,4 selectivity for both isoprene (96.5%, 0 °C) and butadiene (92.8%, 20 °C) polymerizations.
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INTRODUCTION Preparation of polymers with well-defined microstructures and desired properties by regio- and stereospecific selective coordination polymerization has been a long-standing research subject of polymer science, the key of which relies on the innovation of new highly active and selective catalysts. The past half century has witnessed the emergence, industrialization, and utilization of polymeric elastomers deriving from the highly cis1,4-selective polymerization of the 1,3-conjugated diene monomers,1 which have become important supports of the automobile industry. This is mainly benefited from the discovery of Co, Ni, Ti, and, in particular, the rare-earthmetal-based Ziegler−Natta coordination catalysts.1f,2−4 With the shortage of natural resources and increasing environmental pollution, producing and using high-performance tires of low rolling resistance, high wet skid resistance, and low petroleum consuming, so-called “green tires”, have become compulsory. Thus, trans-1,4- and 3,4-regulated polydiene “rubbers” have attracted increasing attention from both academy and industry fields. These are reported to mix with natural rubber or butadiene-styrene rubber in only a small fraction (90%) in toluene at 20 °C (runs 1−4), of which 4/[Ph3C][B(C6F5)4]/AliBu3 still exhibited a promising catalytic activity even at a low temperature (−30 °C, >99% yield in 6 h) and an increased 3,4-selectivity (98.1%, run 5). In contrast, under the same conditions the systems composed of large neodymium and lanthanum complexes 5 and 6 provided only moderate 3,4C
DOI: 10.1021/acs.organomet.5b00502 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics Table 1. Polymerization of Isoprene by Using Complexes 1−6 under Various Conditionsa run 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21e 22f 23g
cat. 1 2 3 4 4 5 6 6 1 2 3 4 4 5 6 6 6 6 6 6 6 6 6
AlR3 i
Al Bu3(5) AliBu3(5) AliBu3(5) AliBu3(5) AliBu3(5) AliBu3(5) AliBu3(5) AliBu3(5) AlEt3(5) AlEt3(5) AlEt3(5) AlEt3(5) AlMe3(5) AlEt3(5) AlEt3(5) AlMe3(5) AlEt3(10) AlEt3(20) AlEt3(5) AlEt3(5) AlEt3(5) AlEt3(5) AlEt3(5)
temp (°C)
time (h)
20 20 20 20 −30 20 20 0 20 20 20 20 20 20 20 20 20 20 0 60 20 20 20
0.25 0.25 0.25 0.25 6 2 2 6 6 2 2 2 2 2 1 1 1 1 6 0.5 1 1 2
yield (%)
microstructureb 3,4/cis-1,4/trans-1,4
Mnc (104)
Mw/Mnc
Tg/Tmd (°C)
92.1/3.4/4.5 94.1/3.9/2.0 90.1/4.3/5.6 94.7/3.2/2.1 98.1/1.3/0.6 76.1/13.5/10.4 62.9/20.1/17.0 72.1/27.9/0 76.0/15.3/8.7 36.5/42.1/21.4 67.0/25.1/7.9 37.2/29.3/33.5 12.9/86.5/0.6 12.3/3.7/84.0 4.5/−/95.5 5.6/5.5/88.9 4.0/−/96.0 3.9/−/96.1 3.5/−/96.5 6.5/1.0/92.5 31.0/8.9/60.1 48.0/2.1/49.9 0.9/6.3/92.8
2.3 2.2 6.1 5.7 15.1 7.9 10.2 5.7 0.4 1.8 1.4 3.7 2.3 4.2 4.1 3.2 3.5 3.0 8.3 4.3 4.0 3.4 5.1
1.74 1.83 1.91 2.20 1.98 2.04 1.75 2.12 1.6 2.81 1.65 3.21 1.98 1.72 1.22 1.24 1.31 1.33 1.25 1.33 1.51 1.45 1.21
30/− 37/− 32/− 30/− 42/− −7/− −23/− −5/− n.d. −45/− n.d. n.d. −66/− −65/− −65/46 −65/− −65/46 −64/44 −64/47 −65/46 n.d. n.d. −/51,60h
> > > > > > >
99 99 99 99 99 99 99 75 30 > 99 > 99 > 99 55 100 > 99 > 99 > 99 > 99 89 > 99 > 99 > 99 > 99
Conditions: toluene 5 mL, cat. 10 μmol, [IP]/[cat.] = 500:1 (mol/mol), [cat.]/[Ph3C][B(C6F5)4] = 1:1. bMeasured by means of 1H NMR and 13C NMR spectroscopy in CDCl3. cDetermined by means of gel permeation chromatography (GPC) against polystyrene standards at 40 °C. d Determined by differential scanning calorimetry (DSC). eAddition of [PhNMe2H][B(C6F5)4] (10 μmol). fAddition of PhNMe2 (10 μmol). g Addition of 5.0 mmol of butadiene in toluene. hMultiple Tm values. a
byproduct of reaction between [PhNMe2H][B(C6F5)4] and 6) into the catalyst system 6/[Ph3C][B(C6F5)4]/AlEt3 also led to a decrease of trans-1,4-content (49.9%). A similar phenomenon was found in other rare-earth-metal-based catalyst systems for isoprene polymerization reported by Anwander.6e The presence of PhNMe2 probably disintegrated the cationic heterobimetallic species upon coordination to the rare-earth-metal center or changed the steric environment of the active species. The kinetic study demonstrated that the conversion increased with polymerization time, which had a linear correlation with the number-average molecular weight (Mn) of the obtained polymer; meanwhile the molecular weight distribution (Mw/Mn) remained narrow (1.25−1.36), suggesting a rare quasi-living trans-1,4-polymerization of isoprene (Figure 5).
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Figure 5. Polymerization of IP with 6/[(Ph3C)(B(C6F5)4)]/AlEt3: molecular weight (solid stars) and molecular weight distribution (hollow triangles) vs conversion.
CONCLUSION In summary, a series of rare-earth-metal bis(alkyl) complexes (Ln = Sc, Lu, Y, Er, Nd, La) bearing a sterically bulky iminophosphonamide ancillary ligand were synthesized and well-defined, which were employed to initiate isoprene polymerization upon activation with aluminum alkyls and organoborate. The catalytic behavior strongly depended on the size of the rare-earth metals and the kinds of aluminum alkyls, of which complexes 1−4 based on the smaller Lu, Sc, Y, Er, etc., metals, with the assistance of AliBu3 and [(Ph3C)(B(C6F5)4)], exhibited high 3,4-selectivities, while those bearing larger La and Nd metals provided moderate 3,4-selectivities, owing to the more open coordination environment, facilitating 1,4-enchainment. As a result, strikingly, these large La and Nd complexes activated by [Ph3C][B(C6F5)4] and less steric AlEt3 gave trans1,4-selectivity up to 96.5% with high activity, realizing for the
first time a change from 3,4- to trans-1,4-selectivity. These results shed new light on controlling the stereoregularity of polydienes by choosing the metal size and the cocatalyst, which establishes an efficient route to access high-performance dienebased elastomers with variable microstructures.
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EXPERIMENTAL SECTION
General Methods. All manipulations were performed under a dry and oxygen-free argon atmosphere using standard high-vacuum Schlenk techniques or in a glovebox. All solvents were purified via an SPS (solvent purification system) system. ClPPh2, 2,6-diisopropylaniline, and LinBu were purchased from Aladdin and used without further purification. Isoprene was purified by distillation over calcium D
DOI: 10.1021/acs.organomet.5b00502 Organometallics XXXX, XXX, XXX−XXX
Article
Organometallics hydride under a nitrogen atmosphere. Azide,12a [Ph3C][B(C6F5)4], [PhNMe2H][B(C6F5)4], B(C6F5)3,12b NPNdippH,7g and LaBr312c were prepared according to the published procedures. 1H and 13C NMR spectra were recorded on a Bruker AV400 (FT, 400 MHz for 1H; 100 MHz for 13C; 162 MHz for 31P) spectrometer. The molecular weight and molecular weight distribution of the polymers were measured with a TOSOH HLC-8220 GPC at 40 °C using THF as eluent (the flow rate was 0.35 mL/min) against polystyrene standards. Differential scanning calorimetry (DSC) analyses were carried out on a Q100 DSC from TA Instruments under a nitrogen atmosphere. IR spectra were obtained on a Bruker Vertex 70 FTIR spectrometer. Elemental analyses were performed at National Analytical Research Centre of Changchun Institute of Applied Chemistry. X-ray Crystallographic Study. Suitable single crystals of complexes were sealed in a thin-walled glass capillary for determining the single-crystal structure. Data collection was performed at 20 °C on a Bruker SMART diffractometer with graphite-monochromated Mo Kα radiation (λ = 0.710 73 Å). The SMART program package was used to determine the unit-cell parameters. The absorption correction was applied using SADABS. The structures were solved by direct methods and refined on F2 by full-matrix least-squares techniques with anisotropic thermal parameters for non-hydrogen atoms. Hydrogen atoms were placed at calculated positions and were included in the structure calculation without further refinement of the parameters. All calculations were carried out using the SHELXS-97 program. Molecular structures were generated using the ORTEP program. Synthesis of (NPNdipp)Sc(CH2SiMe3)2(THF) (1). To a hexane solution (3 mL) of Sc(CH2SiMe3)3(THF)2 (0.45 g, 1 mmol) was added dropwise 1 equiv of a THF solution (5 mL) of NPNdippH (0.536 g, 1 mmol) at ambient temperature. The mixture was stirred for 60 min at ambient temperature, and after removal of all volatiles under reduced pressure, the residue was extracted with hexane. The hexane solution was further concentrated and crystallized at −30 °C to give pale yellow crystalline solids of 1 in 66% isolated yield. 1H NMR (400 MHz, C6D6, 25 °C): δ 0.48 (br s, 4H, CH2SiMe3), 0.33 (s, 18H, SiMe3), 0.96 (b, 24H, CHMe2), 1.24 (br s, 4H, THF-β−CH2), 3.78 (m, 4H, CHMe2), 1.24 (br s, 4H, THF-α−CH2), 6.74−6.95 (m, 5H, Ar−H), 7.06−7.14 (m, 1H, Ar−H), 7.10−7.14 (m, 7H, Ar−H), 7.20− 7.48 (m, 3H, Ar−H), 13C NMR (100 MHz, C6D6, 25 °C): δ 4.05 (s, CH2SiMe3), 24.95 (s, CHMe2), 25.58 (s, CHMe2), 29.02 (s, CHMe2), 43.63 (s, CH2SiMe3), 124.38 (s, Ar−C), 124.82 (s, Ar−C), 131.21 (s, Ar−C), 133.49 (s, Ar−C), 139.98 (s, Ar−C), 142.44 (s, Ar−C), 146.25 (s, Ar−C). 31P NMR (162 MHz, C6D6, 25 °C): δ 24.37. IR (KBr pellets): ν 3662 (w), 3340 (w), 3052 (m), 2961 (m), 2851 (m), 1589 (m), 1434 (m), 1384 (m), 1353 (m), 1315 (m), 1255 (m), 1198 (m), 1110 (m), 1046 (m), 990 (m), 865 (m), 819 (m), 789 (m), 755 (m), 711 (m), 700 (m), 590 (m), 559 (m), 506 (m) cm−1. Anal. Calcd for C48H73N2OPScSi2 (%): C, 69.69; H, 9.02; N, 3.39. Found: C, 69.48; H, 8.95; N, 3.45. Synthesis of (NPNdipp)Y(CH2SiMe3)2(THF) (3). By a procedure similar to that described for the preparation of 1, treatment of Y(CH2SiMe3)3(THF)2 (0.49 g, 1 mmol) with NPNdippH (0.536 g, 1 mmol) gave yellow crystals of 3 (70%). Single crystals suitable for Xray analysis were obtained from a THF/hexane mixture at −30 °C within 2 days. 1H NMR (400 MHz, C6D6, 25 °C): δ 0.03 (s, 4H, CH2SiMe3), 0.34 (s, 18H, SiMe3), 0.60 (b, 12H, CHMe2), 1.21 (br s, 4H, THF-β−CH2), 1.33 (br, 12H, CHMe2), 3.63 (br s, 4H, THF-α− CH2), 3.76 (m, 4H, CHMe2), 6.74−6.97 (m, 7H, Ar−H), 7.04−7.12 (m, 7H, Ar−H), 7.20−7.46 (m, 3H, Ar−H). 13C NMR (100 MHz, C6D6, 25 °C): δ 4.43 (s, CH2SiMe3), 24.11 (s, CHMe2), 24.95 (s, CHMe2), 25.10 (s, CHMe2), 24.91 (s, CHMe2), 29.00 (s, CHMe2), 37.80 (d, CH2SiMe3), 123.98 (s, Ar−C), 124.61 (s, Ar−C), 131.05 (s, Ar−C), 133.43 (s, Ar−C), 141.99 (s, Ar−C), 145.99 (s, Ar−C). 31P NMR (162 MHz, C6D6, 25 °C): δ 21.86. IR (KBr pellets): ν 3668 (w), 3345 (w), 3056 (m), 2965 (m), 2858 (m), 1590 (m), 1468 (m), 1429 (m), 1384 (m), 1355 (m), 1315 (m), 1255 (m), 1198 (m), 1108 (m), 1046 (m), 987 (m), 862 (m), 819 (m), 784 (m), 752 (m), 711 (m), 700 (m), 594 (m), 551 (m), 514 (m) cm−1. Anal. Calcd for C48H73N2OPYSi2 (%): C, 66.18; H, 8.56; N, 3.22. Found: C, 66.48; H, 8.59; N, 3.29.
Synthesis of (NPNdipp)Er(CH2SiMe3)2(THF) (4). By a procedure similar to that described for the preparation of 1, treatment of Er(CH2SiMe3)3(THF)2 (0.48 g, 1 mmol) with NPNdippH (0.536 g, 1 mmol) gave pink crystals of 4 (69%). Single crystals suitable for X-ray analysis were obtained from a THF/hexane mixture at −30 °C within 2 days. IR (KBr pellets): ν 3647 (w), 3370 (w), 3060 (m), 2957 (m), 2870 (m), 1590 (m), 1465 (m), 1430 (m), 1360 (m), 1355 (m), 1252 (m), 1187 (m), 1119 (m), 1060 (m), 987 (m), 864 (m), 789 (m), 756 (m), 695 (m), 592 (m), 519 (m), 506 (m) cm−1. Anal. Calcd for C48H73N2OPErSi2 (%): C, 60.72; H, 7.86; N, 2.95. Found: C, 60.68; H, 7.75; N, 3.00. Synthesis of (NPNdipp)Nd(CH2Ph-4-CH3)2(THF) (5). Solid KCH2Ph4-CH3 (0.432 g, 3 mmol) was dropwise added to a THF (20 mL) suspension of NdCl3(THF)3 (0.463 g, 1 mmol). Within 10 min a green solution had formed. The solution was stirred for 1 h, after which NPNdippH (0.536 g, 1 mmol) was added. The mixture was stirred for 2 h at ambient temperature, and after removal of all volatiles under reduced pressure, the residue was extracted with hexane. The hexane solution was further concentrated and crystallized at −30 °C to give green crystalline solids 5 in 76% isolated yield. IR (KBr pellets): ν 3658 (w), 3358 (w), 3056 (m), 2970 (m), 2871 (m), 1905 (m), 1615 (m), 1602 (m), 1471 (m), 1431 (m), 1385 (m), 1365 (m), 1312 (m), 1260 (m), 1194 (m), 1122 (m), 1036 (m), 904 (m), 794 (m), 780 (m), 749 (m), 711 (m), 695 (m), 663 (m), 584 (m), 509 (m) cm−1. Anal. Calcd for C56H69N2NdOP (%): C, 69.89; H, 7.33; N, 2.91. Found: C, 69.68; H, 7.25; N, 2.89. Synthesis of (NPNdipp)La(CH2Ph-4-CH3)2(THF) (6). Solid KCH2Ph4-CH3 (0.432 g, 3 mmol) was dropwise added to a THF (20 mL) suspension of LaBr3(THF)4 (0.67 g, 1 mmol). Within 10 min a yellowish-brown solution had formed. The solution was stirred for 1 h, after which NPNdippH (0.536 g, 1 mmol) was added. The mixture was stirred for 2 h at ambient temperature, and after removal of all volatiles under reduced pressure, the residue was extracted with hexane. The hexane solution was further concentrated and crystallized at −30 °C to give pale yellow crystalline solids 6 in 86% isolated yield. 1H NMR (400 MHz, C6D6, 25 °C): δ 0.65 (s, 12H, CHMe2), 1.21 (br s, 4H, THF-β−CH2), 1.32 (s, 12H, CHMe2), 2.04 (s, 6H, CH2PhCH3), 2.25 (s, 4H, La−CH2), 3.22 (br s, 4H, THF-α−CH2), 3.81 (m, 4H, CHMe2),6.30 (m, 4H, Ar−H), 6.73 (m,4H, Ar−H), 6.81 (m, 4H, Ar− H), 6.90 (m, 2H, Ar−H),7.10 (m, 2H, Ar−H), 7.18 (m, 4H, Ar−H), 7.29(m, 4H, Ar−H), 13C NMR (100 MHz, C6D6, 25 °C): δ 20.59 (s, La-CH2), 24.82 (s, CHMe2), 25.38 (s, CHMe2), 25.79 (s, CHMe2), 29.07 (s, CHMe2), 66.57 (s, CH2PhCH3), 122.17 (s, Ar−C), 123.59(s, Ar−C), 124.59 (s, Ar−C), 120.78 (s, Ar−C), 132.70 (s, Ar−C), 132.89 (s, Ar−C), 143.23 (s, Ar−C), 145.70 (s, Ar−C), 147.58 (s, Ar−C). 31P NMR (162 MHz, C6D6, 25 °C): δ 17.94. IR (KBr pellets): ν. 3682 (w), 3351 (w), 3062 (m), 2987 (m), 2851 (m), 1897 (m), 1595 (m), 1470 (m), 1430 (m), 1384 (m), 1358 (m), 1264 (m), 1206 (m), 1127 (m), 1048 (m), 1003 (m), 917 (m), 785 (m), 687 (m), 548 (m), 515 (m) cm1. Anal. Calcd for C56H69N2LaOP (%): C, 70.28; H, 7.37; N, 2.93. Found: C, 70.39; H, 7.19; N, 2.86. Isoprene Polymerization. A typical polymerization procedure (run 4, Table 1) is described as follows. Isoprene (0.5 mL, 5 mmol), 1 (9.6 mg, 10 μmol), a toluene solution of AlEt3 (0.05 mmol, 0.1 mL × 0.5 M), and a toluene solution (3 mL) of [Ph3C][B(C6F5)4] (9.6 mg, 10 μmol) were charged into a flask. After 2 h, the viscous reaction solution was poured into ethanol (ca. 40 mL) containing a small amount of hydrochloric acid to terminate the polymerization. The white solid of polyisoprene was precipitated, filtered, washed with ethanol, and dried under vacuum at 45 °C to a constant weight (0.34 g, 100%).
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.organomet.5b00502. 1 H NMR, 13C NMR, and DSC for the selected polyisoprene samples (PDF) E
DOI: 10.1021/acs.organomet.5b00502 Organometallics XXXX, XXX, XXX−XXX
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Organometallics
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A.; Visseaux, M. J. Organomet. Chem. 2002, 647, 167−179. (h) Yang, Y.; Lv, K.; Wang, L.; Wang, Y.; Cui, D. Chem. Commun. 2010, 46, 6150−6152. (i) Liu, D.; Cui, D. Dalton Trans. 2011, 40, 7755−7761. (j) Annunziata, L.; Duc, M.; Carpentier, J.-F. Macromolecules 2011, 44, 7158−7166. (k) Rong, W.; Liu, D.; Zuo, H.; Pan, Y.; Jian, Z.; Li, S.; Cui, D. Organometallics 2013, 32, 1166−1175. (l) Liu, H.; He, J.; Liu, Z.; Lin, Z.; Du, G.; Zhang, S.; Li, X. Macromolecules 2013, 46, 3257− 3265. (7) (a) Barker, J.; Kilner, M. Coord. Chem. Rev. 1994, 133, 219−300. (b) Bailey, P. J.; Pace, S. Coord. Chem. Rev. 2001, 214, 91−141. (c) Coles, M. P. Dalton Trans. 2006, 985−1001. (d) Junk, P. C.; Cole, M. L. Chem. Commun. 2007, 1579−1590. (e) Edelmann, F. T. Adv. Organomet. Chem. 2008, 57, 183−352. (f) Jones, C. Coord. Chem. Rev. 2010, 254, 1273−1289. (g) Stasch, A. Chem. - Eur. J. 2012, 18, 15105− 15112. (8) (a) Liu, B.; Li, S.; Li, D.; Lv, K.; Cui, D.; Sun, G. Chin. J. Appl. Chem. 2012, 29, 1394−1398. (b) Liu, B.; Li, L.; Sun, G.; Liu, D.; Li, S.; Cui, D. Chem. Commun. 2015, 51, 1039−1041. (9) (a) Bambirra, S.; Bouwkamp, M. W.; Meetsma, A.; Hessen, B. J. Am. Chem. Soc. 2004, 126, 9182−9183. (b) Bambirra, S.; Meetsma, A.; Hessen, B. Organometallics 2006, 25, 3454−3462. (10) Shannon, R. D. Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. 1976, 32, 751−767. (11) (a) Klimpel, M. G.; Eppinger, J.; Sirsch, P.; Scherer, W.; Anwander, R. Organometallics 2002, 21, 4021−4023. (b) Bolton, P. D.; Clot, E.; Cowley, A. R.; Mountford, P. Chem. Commun. 2005, 41, 3313−3315. (12) (a) Magnus, P.; Lacour, J.; Weber, W. J. Am. Chem. Soc. 1993, 115, 9347−9348. (b) Piers, W. E.; Chivers, T. Chem. Soc. Rev. 1997, 26, 345−354. (c) Taylor, M. D.; Carter, C. P. J. Inorg. Nucl. Chem. 1962, 24, 387−391.
Summary of crystallographic data for complexes 1, 3, 4, and 6 (CIF)
AUTHOR INFORMATION
Corresponding Authors
*E-mail (S. Li):
[email protected]. *E-mail (D. Liu):
[email protected]. *E-mail (D. Cui):
[email protected]. Fax: (+86) 431 85262774. Tel: +86 431 85262773. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was partly supported by the National Natural Science Foundation of China for project nos. 51073148, 21304088, and 21104074 and the Department of Science and Technology of Jilin Province for project no. 20150204079GX.
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REFERENCES
(1) (a) Porri, L.; Giarrusso, A.; Ricci, G. Prog. Polym. Sci. 1991, 16, 405−321. (b) Kuran, W. Principle of Coordination Polymerization; John Wiley and Sons Ltd.: New York, 2001; pp 275−321. (c) Tobisch, S. Acc. Chem. Res. 2002, 35, 96−104. (d) Arndt, S.; Okuda, J. Adv. Synth. Catal. 2005, 347, 339−354. (e) Friebe, L.; Nuyken, O.; Obrecht, W. Adv. Polym. Sci. 2006, 204, 1−154. (f) Fischbach, A.; Anwander, R. Adv. Polym. Sci. 2006, 204, 155. (g) Zeimentz, P. M.; Arndt, S.; Elvidge, B. R.; Okuda, J. Chem. Rev. 2006, 106, 2404−2433. (h) Baugh. L. S.; Canich. J. A. M. Stereoselective Polymerization with Single-Site Catalysts; Taylor & Francis: New York, 2008; pp 447−466. (2) Zhang, Z. C.; Cui, D. M.; Wang, B. L.; Liu, B.; Yang, Y. Struct. Bonding (Berlin) 2010, 137, 49−108. (3) (a) Gao, W.; Cui, D. M. J. Am. Chem. Soc. 2008, 130, 4984−4991. (b) Lv, K.; Cui, D. M. Organometallics 2010, 29, 2987−2993. (c) Li, D. F.; Li, S. H.; Cui, D. M.; Zhang, X. Q. Organometallics 2010, 29, 2186− 2193. (d) Wang, L. F.; Liu, D. T.; Cui, D. M. Organometallics 2012, 31, 6014−6021. (e) Kaita, S.; Yamanaka, M.; Horiuchi, A. C.; Wakatsuki, Y. Macromolecules 2006, 39, 1359−1363. (4) (a) Fischbach, A.; Klimpel, M. G.; Widenmeyer, M.; Herdtweck, E.; Scherer, W.; Anwander, R. Angew. Chem., Int. Ed. 2004, 43, 2234− 2239. (b) Zhang, L.; Suzuki, T.; Luo, Y.; Nishiura, M.; Hou, Z. Angew. Chem., Int. Ed. 2007, 46, 1909−1913. (c) Zhang, L.; Nishiura, M.; Yuki, M.; Luo, Y.; Hou, Z. Angew. Chem., Int. Ed. 2008, 47, 2642− 2645. (5) (a) Zhang, L.; Luo, Y.; Hou, Z. J. Am. Chem. Soc. 2005, 127, 14562−14563. (b) Li, S. H.; Miao, W.; Tang, T.; Dong, W. M.; Zhang, X. Q.; Cui, D. M. Organometallics 2008, 27, 718−725. (c) Wang, B. L.; Cui, D. M.; Lv, K. Macromolecules 2008, 41, 1983−1988. (d) Li, S. H.; Cui, D. M.; Li, D. F.; Hou, Z. M. Organometallics 2009, 28, 4814− 4822. (e) Döring, C.; Kretschmer, W. P.; Bauer, T.; Kempe, R. Eur. J. Inorg. Chem. 2009, 2009, 4255−4264. (f) Du, G.; Wei, Y.; Ai, L.; Chen, Y.; Xu, Q.; Liu, X.; Zhang, S.; Hou, Z.; Li, X. Organometallics 2011, 30, 160−170. (g) Liu, B.; Li, L.; Sun, G.; Liu, J.; Wang, M.; Li, S.; Cui, D. Macromolecules 2014, 47, 4971−4978. (h) Yao, C. G.; Liu, D. T.; Li, P.; Wu, C. J.; Li, S. H.; Liu, B.; Cui, D. M. Organometallics 2014, 33, 684−691. (6) (a) Baudry-Barbier, D.; Andre, N.; Dormond, A.; Pardes, C.; Richard, P.; Visseaux, M.; Zhu, C. Eur. J. Inorg. Chem. 1998, 1998, 1721−1727. (b) Bonnet, F.; Visseaux, M.; Pereira, A.; Barbier-Baudry, D. Macromolecules 2005, 38, 3162−3169. (c) Bonnet, F.; Visseaux, M.; Pereira, A.; Barbier-Baudry, D. Macromol. Rapid Commun. 2004, 25, 873−877. (d) Ajellal, N.; Furlan, L.; Thomas, C.; Casagrande, O. L., Jr.; Carpentier, J. F. Macromol. Rapid Commun. 2006, 27, 338−343. (e) Milione, S.; Cuomo, C.; Capacchione, C.; Zannoni, C.; Grassi, A.; Proto, A. Macromolecules 2007, 40, 5638−5643. (f) Zimmermann, M.; Tornroos, K. W.; Anwander, R. Angew. Chem., Int. Ed. 2008, 47, 775− 778. (g) Barbier-Baudry, D.; Bonnet, F.; Domenichini, B.; Dormond, F
DOI: 10.1021/acs.organomet.5b00502 Organometallics XXXX, XXX, XXX−XXX
