Copolymerizations of Norbornene and Tetracyclododecene with α

Dec 24, 2015 - Department of Chemistry, Faculty of Science and Engineering, Tokyo Metropolitan University, 1-1 minami Osawa, Hachioji, Tokyo 192-0397,...
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Copolymerizations of Norbornene and Tetracyclododecene with α‑Olefins by Half-Titanocene Catalysts: Efficient Synthesis of Highly Transparent, Thermal Resistance Polymers Weizhen Zhao and Kotohiro Nomura* Department of Chemistry, Faculty of Science and Engineering, Tokyo Metropolitan University, 1-1 minami Osawa, Hachioji, Tokyo 192-0397, Japan S Supporting Information *

ABSTRACT: Highly efficient synthesis of cyclic olefin (CO) copolymers with high glass transition temperatures (Tg) as well as high catalytic activity have been attained not only by copolymerization of norbornene (NBE) with α-olefins (1hexene, 1-octene, 1-dodecene), but also by copolymerization of tetracyclododecene (TCD) with α-olefins using halftitanocene catalysts, Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)] in the presence of MAO. Linear relationships between the Tg values and the NBE or TCD contents were observed in all cases; Tg values in poly(TCD-co-α-olefin)s were higher than those in poly(NBE-co-α-olefin)s with the same CO contents. NBE and TCD incorporations in these copolymerization under high NBE or TCD feed conditions (especially by 2) were not affected by α-olefin (number of methylene units in the side chain) employed. An introduction of terminal olefinic double bond into the polymer side chain could be attained, if the copolymerization of NBE with 1-octene by 1 was conducted in the presence of 1,7-octadiene.

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half-titanocenes,10 and the others.11 These cyclic olefin copolymers are commercialized (as TOPAS) by using metallocene catalysts as ultrapure (applicable to advanced pharma packaging, food contact films), crystal-clear (glass clear, amorphous), high barrier (resistant to moisture, alcohols, acids) materials.12 However, successful examples for the efficient synthesis of random, high molecular weight copolymers with high NBE contents (>50 mol %), which possess high Tg (>150 °C), still have been limited.10c In contrast to many reports for the ethylene/NBE copolymerization, examples for copolymerization of NBE with α-olefin have been limited, although these are also promising materials with the above properties as well as expecting better property by introduction of alkyl branching (modification of comonomers). This seems to be due to a difficulty of α-olefin insertion after NBE incorporation using linked-metallocene catalysts, pointed out in the previous reviewing article by Tritto et al.7e In fact, both the catalytic activity and the Mn values decreased upon increasing the αolefin contents in the NBE/1-octene copolymerization using [H2C(Me2C5H2)2]ZrCl2 (ex.: activity 200 kg-polymer/mol-Zr· h, Mw = 8500, NBE cont. 65.6 mol %, Tg = 85 °C).13d As one exception, fluorenyl-based linked half-titanocenes, exemplified as [Me2Si(fluorenyl)(NtBu)]TiMe2, (Flu-CGC) reported by

INTRODUCTION Polyolefins are important commercial synthetic polymers, and metal catalyzed olefin polymerization is the core technology in industry. Synthesis of new polymers with specified functions has been considered to be one of the most attractive target, and precise control in the copolymerization is thus an important method that usually allows the alteration of the (physical, mechanical, and electronic) properties by varying the ratio of individual components. Design of the molecular catalysts attracts considerable attention in terms of synthesis of new polymers; recent progress in the newly designed catalysts offers several new possibilities.1−6 Certain cyclic olefin copolymers (COCs) and cyclic olefin polymers (COPs) are amorphous materials with a promising combination of high transparency in the UV−vis region along with humidity-, heat-resistance (high glass transition temperature, Tg).7 Three processes such as (1) ring-opening metathesis polymerization (ROMP) of multicyclic olefins and subsequent hydrogenation, (2) coordination copolymerization of ethylene with cyclic olefins, and (3) homopolymerization of cyclic olefins, are generally known for the practical production. In particular, the copolymerization approach seems promising, because the desired properties (Tg etc.) should be tuned by their compositions (cyclic olefin contents etc.) as well as their microstructures (including tacticity etc.). Many examples have thus been known for the copolymerization of ethylene with norbornene (NBE) using ordinary metallocenes,8 linked halftitanocenes (so-called constrained geometry type),9 nonbridged © XXXX American Chemical Society

Received: October 2, 2015 Revised: December 12, 2015

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DOI: 10.1021/acs.macromol.5b02176 Macromolecules XXXX, XXX, XXX−XXX

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copolymerizations.4,10,15 These copolymerizations were terminated after certain period to control the monomer conversion less than 10% for obtainment of the copolymers with uniform compositions. The results are summarized in Tables 1 and 2. It turned out, as shown in Table 1, that the copolymerizations of NBE with 1-hexene (HX), 1-octene (OC), and with 1dodecene (DD) by 1,2 − MAO catalysts afforded high molecular weight copolymers not only with unimodal molecular weight distributions, but also with uniform compositions confirmed by DSC theromograms [observed as a sole glass transition temperature (Tg)].22 Moreover, as also described below, the Tg values increased upon increasing the NBE contents estimated by 13C NMR spectra22 according to the previous reports.15c,d The copolymerization of NBE with 1-hexene (HX) by (tBuC5H4)TiCl2(NCtBu2) (1) − MAO catalyst proceeded with moderate catalytic activities (based on polymer yields) that are comparable to those by the reported [Me2Si(fluorenyl)(NtBu)]TiMe2 (Flu-CGC)−Ph3CB(C6F5)4 catalyst,15c and the activity increased upon increasing the NBE concentration charged (runs 1−4). The NBE incorporation (estimated by 13C NMR spectra) by 1 was lower than that by Flu-CGC;15c and the results thus suggest, in other words, that the NBE contents can be modified simply by varying the NBE/ HX feed molar ratio for synthesis of copolymers even with rather low NBE contents. It should be noted that the Cp analogue (2) showed >10 times higher catalytic activities and better NBE incorporation than the tBuC5H4 analogue (1) under the same conditions [ex.: activity: 1220 kg-polymer/mol-Ti·h, NBE 47.0 mol % (run 4) vs 12500 kg-polymer/mol-Ti·h, NBE 69.2 mol % (run 20)]. It is also noteworthy that the Tg values (corresponding to NBE contents in the resultant copolymers) were not affected by the kind of Al cocatalyst employed (MAO or MMAO, runs 16− 19). Moreover, a good correlation between Tg values and NBE contents in poly(NBE-co-HX)s were observed irrespective of the cyclopentadienyl fragment (1 and 2, Figure 1a). These would be unique contrast to those reported previously (exemplified by Flu-CGC), in which the plots (slope) are affected by substituent on the fluorenyl ligand,15d as well as cocatalyst employed.15c,d Similarly, the copolymerizations of NBE with 1-octene (OC) by 1,2 − MAO catalysts proceeded with high catalytic activities (runs 5−8,21−24). Both the activity and the NBE incorporation by 2 were higher than that by 1 under the same conditions [ex.: activity: 1720 kg-polymer/mol-Ti·h, NBE 37.0 mol % (run 7) vs 7890 kg-polymer/mol-Ti·h, NBE 67.5 mol % (run 23)]. The activities by 2 on the basis of polymer yields were not strongly affected by the initial NBE/OC feed ratios (runs 21−24), whereas the activity by 1 increased upon increasing the initial NBE concentration charged under certain conditions (runs 5−7). Similar trends (both the activities and NBE incorporations) were observed in the copolymerization of NBE with 1-dodenece (DD) by 1,2−MAO catalysts, affording the copolymers with uniform compositions (confirmed by DSC thermograms). Moreover, these copolymerization results were highly reproducible (exemplified as runs 10−11, 12−13, 27− 28, and 29−30). It turned out that good linear relationships between Tg values and NBE contents in poly(NBE-co-HX)s (Figure 1a), poly(NBE-co-OC)s (Figure 1b), and poly(NBE-co-DD)s (Figure 1c) were observed irrespective of kind of titanium catalysts (1 and 2) employed, and Tg values in the resultant copolymers

Shiono et al. afforded copolymers of NBE not only with propylene,14 but also withα-olefin (1-hexene, 1-octene, 1decene),15 and the resultant polymers by Flu-CGC possessed narrow molecular weight distributions because of nature of livingness as observed in the NBE polymerization16 as well as in propylene polymerization.17 However, the activities especially by Flu-CGC were low and the α-olefin contents were dependent upon the ligand substituents and cocatalyst empolyed.14,15 More recently, we realized that the ketimide-modified halftitanocenes, CpTiCl2(NCtBu2), which are effective catalysts for ethylene/NBE copolymerization,10c showed higher catalytic activity with efficient NBE incorporation in the copolymerization of NBE with α-olefins (1-hexene, 1-octene)18 than the 1,3imidazolin-2-iminato analogues, CpTiCl2[1,3-tBu2(CHN)2C N],10e affording high molecular weight polymers with uniform molecular weight distribution as well as compositions (Scheme 1).18 Moreover, as far as we know, examples of copolymerizaScheme 1. Copolymerization of Norbornene (NBE), Tetracyclododecene (TCD) with α-Olefin (1-Hexene, 1Octene, 1-Dodecene) Using Cp′TiCl2(NCtBu2) [Cp′ = t BuC5H4 (1), C5H5 (2, Cp)]−MAO Catalysts

tion of tetracyclododecene (TCD) with α-olefins (affording high molecular weight copolymers) have not so far been reported,19 we thus explored copolymerization of NBE, TCD with α-olefins (1-hexene, 1-octene, and 1-dodecene) using a series of half-titanocenes. We also wish to demonstrate an introduction of terminal olefinic double bond into poly(NBEco-1-octene)s conducted by copolymerization of NBE with 1octene in the presence of 1,7-octadiene.20

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RESULTS AND DISCUSSION 1. Copolymerization of Norbornene (NBE) with 1Hexene (HX), 1-Octene (OC), and 1-Dodecene (DD) by Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)]−MAO Catalysts. Half-titanocenes containing ketimide ligands, Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), C5H5 (2, Cp)], have been chosen in this study, not only because 2 showed efficient NBE incorporation with high catalytic activity in the ethylene/NBE copolymerization,10c but also because 1 showed efficient cyclopentene incorporation in the ethylene/cyclopentene copolymerization.21 MAO and MMAO white solids by removing toluene (or n-hexane) and AlMe3 and/or AliBu3 from commercially available MAO (methyl aluminoxane; PMAO-S, Tosoh Finechem Co.) or MMAO (modified MAO, methylisobutyl aluminoxane, Me/iBu = 2.67; MMAO-3A-H, Tosoh Finechem Co.) have been chosen as Al cocatalysts, because these Al cocatalysts were found to be effective in the ethylene B

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Macromolecules Table 1. Copolymerization of Norbornene (NBE) with 1-Hexene (HX), 1-Octene (OC), and 1-Dodecene (DD) by Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)]−MAO Catalystsa run 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17g 18 19g 20 21 22 23 24 25 26 27 28 29 30

catalyst (μmol) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

(1.0) (0.30) (0.20) (0.20) (1.0) (0.30) (0.20) (0.20) (1.0) (0.30) (0.30) (0.30) (0.30) (0.20) (0.04) (0.04) (0.20) (0.03) (0.20) (0.02) (0.10) (0.05) (0.03) (0.03) (0.10) (0.10) (0.03) (0.03) (0.03) (0.03)

α-olefin

NBE/M

NBE feed ratiob/ %

time/min

yield/mg

activityc

Mnd × 10−4

Mw/Mnd

NBE cont.e/mol %

Tgf/°C

HX HX HX HX OC OC OC OC DD DD DD DD DD DD HX HX HX HX HX HX OC OC OC OC DD DD DD DD DD DD

1.0 1.0 1.9 9.7 1.0 1.9 5.8 9.7 1.0 1.9 1.9 5.8 5.8 9.7 1.0 1.9 1.9 5.8 5.8 9.7 1.0 1.9 5.8 9.7 1.0 1.9 5.8 5.8 9.7 9.7

12 12 21 57 14 25 50 63 19 32 32 59 59 70 12 21 21 44 44 57 14 25 50 63 19 32 59 59 70 70

60 60 60 60 60 60 60 60 60 60 60 60 60 60 30 30 20 60 20 60 60 20 60 60 60 60 60 60 60 60

699 190 184 244 664 308 343 186 359 250 253 412 410 329 150 192 132 386 179 250 614 137 236 186 321 449 130 137 124 122

699 633 918 1220 664 1210 1720 930 359 833 843 1370 1370 1650 7500 9620 1980 12900 2690 12500 6140 8240 7890 6220 3210 4490 4320 4580 4150 4060

3.77 4.55 5.36 6.07 4.71 5.60 6.49 6.34 5.18 6.37 6.10 6.68 6.85 6.61 4.18 3.61 3.58 4.09 3.46 3.94 4.57 3.33 4.18 4.79 4.18 3.84 5.43 5.42 8.26 8.89

1.69 1.75 1.75 1.71 1.73 1.70 1.69 1.68 1.71 1.62 1.64 1.76 1.70 1.64 1.64 1.58 1.63 1.72 1.59 1.61 1.67 1.63 1.67 3.24 1.70 1.67 1.80 1.75 3.19 3.24

9.6 9.6 31.7 47.0

46 57 89 161

24.4 37.0 49.2 15.0

61 102 135

17.4 43.0

18 64

55.0 20.0 37.2

69.2 13.0 39.6 67.5 77.6

100 78 126 129 211 211 246 31 99 192 235

37.3

56

76.1 84.1

157 212

64.5

a

Conditions: toluene 0.5 mL, 1-hexene 5.0 mL (HX 7.3 M), 1-octene 5.0 mL (OC 5.8 M), 1-dodecene 5.0 mL (DD 4.1 M), and MAO 1.0 mmol, 25 °C. bNBE initial feed molar ratio. cActivity = kg-polymer/mol-Ti·h. dGPC data in THF vs polystyrene standards. eNBE content estimated by 13C NMR spectra. fGlass transition temperature (Tg) measured by DSC thermogram. gMMAO-3A-H (modified methylaluminoxane), Me/iBu = 2.67, 1.0 mmol.

Table 2. Effect of Polymerization Time and Temperature in Copolymerization of Norbornene (NBE) with 1-Hexene (HX) and 1-Octene (OC) by CpTiCl2(NCtBu2) (2)−MAO Catalysta run

cat. 2/μmol

α-olefin

NBE/M

temp/°C

time/min

yield/mg

activityc

Mnd × 10−4

Mw/Mnd

Tge/°C

31 32 15 33 22 34 35 36 37 23 38 39 40 41 42 43

0.04 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.03 0.03 0.03 0.03 0.03 0.03 0.03

HX HX HX HX OC OC OC OC OC OC OC OC OC OC OC OC

1.0 1.0 1.0 1.0 1.9 1.9 1.9 1.9 1.9 5.8 5.8 5.8 5.8 5.8 5.8 5.8

25 25 25 25 25 25 25 25 25 25 25 25 50 50 70 70

15 15 30 30 20 40 40 60 60 60 30 30 30 30 30 30

122 120 150 142 137 204 201 274 270 236 77 81 186 153 137 123

12200 12000 7500 7120 8240 6120 6040 5470 5400 7890 5160 5400 12400 10200 9170 8170

4.10

1.60

79

4.18

1.64

78

3.33 3.37

1.63 1.62

99 97

3.37

1.61

94

4.18 4.02 3.89 3.33 3.49 2.80 2.90

1.67 1.68 1.71 1.65 1.65 1.60 1.61

192 192 190 190

a

Conditions: toluene 0.5 mL, 1-hexene 5.0 mL (HX 7.3 M), 1-octene 5.0 mL (OC 5.8 M), and MAO 1.0 mmol. bActivity = kg-polymer/mol-Ti·h. GPC data in THF vs polystyrene standard. dNBE content estimated by 13C NMR spectra. eGlass transition temperature (Tg) measured by DSC thermogram. c

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concentration in the solution).23 No significant differences in their Tg values (NBE contents in the copolymers) were observed under these conditions. In contrast, the observed activity was not strongly affected over time course, when these polymerizations were conducted under rather high NBE concentration conditions (runs 23, 38, and 39). As observed in the ethylene/NBE copolymerization by 2−MAO catalyst,10c the activity by 2 increased at high temperature especially at 50 °C, and no significant differences in the Tg values (NBE contents) in the resultant copolymers were observed by varying the temperature (25−70 °C). These would suggest that significant temperature dependence toward the NBE incorporations (as observed in ethylene/α-olefin copolymerization by ordinary ansa metallocene catalysts)24 was not seen in this catalysis. Figure 3 shows selected 13C NMR spectra (in 1,1,2,2tetrachloroethane-d2 solution at 110 °C) for poly(NBE-co-1hexene), poly(NBE-co-1-octene)s, and poly(NBE-co-1-dodecene).22 Most of typical resonances could be assigned according to the previous reports,15 and the NBE contents were also estimated in on the basis those in the copolymers with 1hexene, 1-octene reported previously.15 Although it seems difficult to assign all resonances (such as resonances ascribed to carbon in repeated, alternating NBE incorporations etc.), significant differences were not observed in the resultant copolymers by the substituent on Cp′ in Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)] (Figure 3c,d). As suggested in the previous reports15 as well as from the above results (especially in plots of Tg with NBE contents), as also observed in poly(ethylene-co-NBE)s prepared by 2,10c it seems likely in high certainty that the resultant copolymers are random copolymers containing isolated, alternating, and repeated NBE incorporations. 2. Copolymerization of Tetracyclododecene (TCD) with 1-Hexene (HX), 1-Octene (OC), and 1-Dodecene (DD). As described in the introductory, copolymerization of tetracyclododecene (TCD) with α-olefins (affording high molecular weight copolymers) have not so far been reported,19 although there are some reports for copolymerization of NBE with 1-hexene, 1-octene, and with 1-decene.15 As described below, it was expected that the resultant copolymers containing TCD possess higher Tg values than those containing NBE under the same cyclic olefin contents and better transparency by introduction of additional cyclic segment. We thus explored the copolymerization using the ketimide-modified halftitanocenes, Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)]−MAO catalysts (Scheme 2). The copolymerization by linked half-titanocene, [Me2Si(C5Me4)(NtBu)]TiCl2 (3), and conventional metallocenes, [Et(indenyl)2]ZrCl2 (4) and Cp2ZrCl2 (5), were also explored for comparison. The results are summarized in Table 3.25 It turned out that, as expected from the copolymerization data with NBE (Tables 1 and 2), the copolymerization of TCD with 1-hexene (HX) by the Cp−ketimide analogue (2) afforded the copolymers not only with unimodal molecular weight distributions, but also with uniform compositions confirmed by DSC thermograms (Table 3, runs 45, 46).22 It also turned out that the copolymerizations with 1-octene (OC), 1-dodecene (DD) by 2 afforded copolymers with high Tg values (runs 54, 59; Tg = 235, 165 °C, respectively) as well as with unimodal molecular weight distributions. In contrast, 1 showed the low activity in the copolymerization with HX, OC, and with DD (runs 44,53,58). Note that attempted copolymerizations of

Figure 1. Plots of glass transition temperature (Tg) vs NBE content (mol %) in (a) poly(NBE-co-1-hexene)s, (b) poly(NBE-co-1-octene)s, (c) poly(NBE-co-1-dodecene)s, and (d) sum of parts a−c. Detailed data are shown in Table 1.

were affected by α-olefin employed; Tg values with the same NBE content increased in the order: poly(NBE-co-DD) < poly(NBE-co-OC)s < poly(NBE-co-HX)s (Figure 1d). As far as we know, these are the first clear demonstration for the relationship as well as the achievement of synthesis of a series of poly(NBE-co-α-olefin)s. Moreover, note that the NBE incorporations in these copolymerizations by 1,2−MAO catalysts were not strongly affected by the nature of α-olefin employed (number of methylene units in the side chain, branching, HX, OC, DD, Figure 2); relatively linear

Figure 2. Plots of NBE content (mol %) vs NBE/α-olefin feed molar ratio in NBE/α-olefin copolymerization by (a) (tBuC5H4)TiCl2(N CtBu2) (1) or (b) CpTiCl2(NCtBu2) (2)−MAO catalyst. Detailed data are shown in Table 1.

correlations between NBE contents in the copolymers and NBE/α-olefin feed molar ratios were observed irrespective of kind of α-olefins employed (even with 1-dodecene), especially under high NBE/α-olefin feed ratio conditions. These would be one of the unique characteristics for using these catalyses; synthesis of high molecular weight copolymers of (long chain) α-olefins with various NBE contents (with uniform molecular weight distributions, compositions) has been achieved by adopting these catalyses. As shown in Table 2, the activities in the copolymerization of NBE with HX, OC by 2−MAO catalyst apparently decreased over time course when the polymerizations were conducted under rather low NBE concentrations (runs 15, 22, and 31− 37), as observed previously in 1-hexene polymerization by 2− MAO catalyst (suggested as due to a decrease in 1-hexene D

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Figure 3. 13C NMR spectra (in 1,1,2,2-tetrachloroethane-d2 at 110 °C) for (a) poly(NBE-co-1-hexene) (run 18, NBE 64.5 mol %), (b) poly(NBE-co1-dodecene) (run 28, NBE 76.1 mol %), (c) poly(NBE-co-1-octene) (run 22, NBE 39.6 mol %) prepared by 2−MAO catalyst, and (d) poly(NBEco-1-octene) (run 7, NBE 37.0 mol %) prepared by 1−MAO catalyst. Detailed data are shown in Table 1.

These (by 3−5) are unique contrasts to that observed by CpTiCl2(NtBu2) (2). Table 4 summarizes results for copolymerization of TCD with 1-hexene (HX), 1-octene (OC) and with 1-dodecene (DD) using CpTiCl2(NCtBu2) (2)−MAO catalyst under various TCD/α-olefin feed molar ratios.22 The activity (on the basis of polymer yield) in the TCD/HX copolymerization decreased upon increasing the TCD concentration charged with increasing the TCD content in the copolymer (runs 45, 46, 63−67, 69, and 70). The resultant copolymers possessed rather high molecular weights with unimodal molecular weight distributions (Mn = 12 000−27 600, Mw/Mn = 1.20−1.76, runs 45, 46, and 63−70), and TCD content (estimated by 13C NMR spectra, shown below)22 in the resultant copolymer increased upon increasing TCD concentration charged with increasing the glass transition temperature (Tg); synthesis of the copolymers with high Tg (286−7 °C, runs 66 and 69) could be thus attained by adopting this catalysis. As demonstrated in Table 4, the polymerization results were reproducible (runs 63 and 64, 45 and 65, 46 and 67, and 69 and 70). The activity was also affected by MAO charged especially under high TCD concentration conditions (runs 46 and 66−68); no significant differences toward both molecular weights and Tg values in the copolymers were, however, observed. Similarly, the copolymerizations of TCD with OC, DD afforded copolymers possessing rather high molecular weights with unimodal molecular weight distributions (Mn = 9900−25 600, Mw/Mn = 1.61−1.93, runs 54, 59, and 71−86); TCD content (estimated by 13C NMR spectra)22 in the resultant copolymer increased upon increasing TCD concentration charged with increase in the glass transition temperature. As shown in Figure 4, good linear relationships between the Tg values and the TCD contents in poly(TCD-co-HX)s, poly(TCD-co-OC)s, and poly(TCD-co-DD)s were observed. It also turned out that Tg values in the resultant copolymers are affected by α-olefin employed, Tg value seems to reach a certain value in the copolymers at high TCD content. The Tg values under the same TCD content increased in the order:

Scheme 2. Copolymerization of TCD with 1-Hexene (HX), 1-Octene (OC), and 1-Dodecene (DD) by Cp′TiCl2(N CtBu2) [Cp′ = tBuC5H4 (1), Cp (2)], [Me2Si(C5Me4)(NtBu)]TiCl2 (3), [Et(indenyl)2]ZrCl2 (4), Cp2ZrCl2 (5)−MAO Catalysts

TCD with HX by [Me2Si(C5Me4)(NtBu)]TiCl2 (3)−MAO catalysts afforded negligible amount of polymers in most cases (runs 47,48, additional data shown in the Supporting Information);25 low molecular weight oligomer (Mn = 5300) with low TCD content (estimated by DSC thermogram, Tg = 9.8 °C) was obtained only if the polymerization was conducted under rather high catalyst concentration in the presence of MAO with large extent (run 47). The copolymerization with HX by [Et(indenyl)2]ZrCl2 (4) afforded small amount of oligomer (Mn = 730) under certain conditions (runs 49,50);25 the copolymerization by Cp2ZrCl2 (5) also afforded oligomers (Mn = 1400, 1500, runs 51, 52). The copolymerization with OC, DD using 3−5−MAO catalysts also afforded oligomers (runs 55−57 and 60−62), and Tg values in the oligomers prepared by 5 possessed higher than those by 3 (runs 55,60). E

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Table 3. Copolymerization of TCD with 1-Hexene (HX), 1-Octene (OC), and 1-Dodecene (DD) by Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)], [Me2Si(C5Me4)(NtBu)]TiCl2 (3), [Et(indenyl)2]ZrCl2 (4), Cp2ZrCl2 (5)−MAO Catalystsa run 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62

cat. (μmol) 1 2 2 3 3 4 4 5 5 1 2 3 4 5 1 2 3 4 5

(0.50) (0.20) (0.20) (10) (20) (20) (20) (20) (20) (0.60) (0.30) (20) (20) (20) (1.0) (0.40) (20) (20) (20)

MAO/mmol

α-olefin/mL

TCD feed ratiob/%

time/min

yield/mg

activityc

Mnd × 10−3

Mw/Mnd

Tge/°C

1.0 1.0 1.5 6.0 10 10 10 10 10 1.5 1.5 10 10 10 1.5 1.5 10 10 10

HX (1.68) HX (1.68) HX (0.56) HX (1.68) HX (0.56) HX (1.68) HX (0.56) HX (1.68) HX (0.56) OC (0.70) OC (0.70) OC (0.70) OC (0.70) OC (0.70) DD (1.00) DD (1.00) DD (1.00) DD (1.00) DD (1.00)

50 50 75 50 75 50 75 50 75 75 75 75 75 75 75 75 75 75 75

15 15 15 30 60 15 10 90 120 15 15 60 20 120 15 15 90 20 120

38 229 143 155 68 62 164 92 40 18 152 129 176 34 16 183 157 143 26

307 4590 2870 31 3.4

17.6 12.2 5.3

1.70 1.76 1.41

205 271 9.8 50

49 3.1 1.0 120 2030 6 26 0.9 62 1830 5.2 21.5 0.7

0.73 1.5 1.4

1.18 1.31 1.27

9.9 3.6 0.76 1.5

1.93 1.37 1.22 1.28

235 6.3

13.0 4.1 0.71 1.6

1.67 1.36 1.25 1.28

165 −21

81 98

83

62

Conditions: toluene 1.0 mL, TCD 2.0 mL (13.4 mmol), 25 °C. bTCD initial feed molar ratio. cActivity = kg-polymer/mol-M·h. dGPC data in THF vs polystyrene standard. eGlass transition temperature (Tg) measured by DSC thermogram. a

Table 4. Copolymerization of TCD with 1-Hexene (HX), 1-Octene (OC), and 1-Dodecene (DD) by CpTiCl2(NCtBu2) (2)− MAO Catalysta run

cat. 2/μmol

α-olefin

feed ratiob TCD:α-olefin

yield/mg

activityc

Mnd × 10−4

Mw/Mnd

TCD cont.f/mol %

Tgf/°C

63 64 45 65 66 46g 67g 68h 69 70 71 72 73 74 54g 75h 76 77 78 79 80 81 82 59g 83g 84h 85 86

0.10 0.10 0.20 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.10 0.20 0.20 0.30 0.30 0.30 0.40 0.40 0.10 0.10 0.30 0.30 0.40 0.40 0.40 0.40 0.50 0.50

HX HX HX HX HX HX HX HX HX HX OC OC OC OC OC OC OC OC DD DD DD DD DD DD DD DD DD DD

1.0:3.0 1.0:3.0 1.0:1.0 1.0:1.0 3.0:1.0 3.0:1.0 3.0:1.0 3.0:1.0 5.0:1.0 5.0:1.0 1.0:3.0 1.0:1.0 1.0:1.0 3.0:1.0 3.0:1.0 3.0:1.0 5.0:1.0 5.0:1.0 1.0:3.0 1.0:3.0 1.0:1.0 1.0:1.0 3.0:1.0 3.0:1.0 3.0:1.0 3.0:1.0 5.0:1.0 5.0:1.0

124 121 229 223 128 143 139 131 160 153 128 210 198 115 152 157 141 135 123 122 234 229 146 183 180 190 159 157

4960 4840 4590 4450 2560 2870 2780 2620 2130 2040 5110 4210 3950 1540 2030 2090 1410 1350 4940 4880 3120 3050 1460 1830 1800 1900 1270 1260

2.76

1.57

28.9

158

1.76

1.70

41.6

205

1.42 1.22

1.66 1.76

62.8

287 271

1.37 1.20

1.71 1.66

67.8

286

2.48 1.83

1.63 1.61

35.0 44.4

102 172

1.44 0.99 1.14 1.03

1.61 1.93 1.81 1.74

2.56

67.6

241 235 233 259

1.65

38.1

36

1.64

1.64

49.1

93

1.37 1.30 1.28 1.38 1.07

1.71 1.67 1.68 1.70 1.68

60.5

162 165

64.6

189

55.5

Conditions: toluene 1.0 mL, TCD 2.0 mL, and MAO 1.0 mmol, 15 min, 25 °C. bTCD initial feed molar ratio. cActivity = kg-polymer/mol-Ti·h. GPC data in THF vs polystyrene standards. fTCD content estimated by 13C NMR spectra. fGlass transition temperature (Tg) measured by DSC thermogram. gMAO 1.5 mmol. hMAO 2.0 mmol. a

d

F

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α-olefin feed conditions; relatively linear correlations were observed between TCD contents in the copolymers and TCD/ α-olefin feed molar ratios. The TCD content [especially under low TCD/α-olefin feed molar ratios (1.0/3.0)] increased in the order: poly(TCD-co-HX) (TCD 28.9 mol %, run 63) < poly(TCD-co-OC) (TCD 35.0 mol %, run 71) < poly(TCD-coDD) (TCD 38.1 mol %, run 78). The results would also suggest that TCD incorporation seems rather favored than that of α-olefin. Synthesis of high molecular weight copolymers of (long chain) α-olefins with various TCD contents (with uniform molecular weight distributions, compositions) has been achieved by adopting these catalyses. As shown in Table 5, catalytic activities in the copolymerizations of TCD with OC by 2−MAO catalyst decreased over time course (runs 46, 87, and 88), and no significant differences in Mn values as well as Tg values (TCD contents in the copolymers) in the resultant copolymers were observed. The activity at 50 °C was close to that at 25 °C, and the activity decreased at 70 °C; Tg value in the resultant copolymer seemed slightly increasing along with decrease in the Mn value (runs 46, 89, and 90). Figure 6 shows selected 13C NMR spectra and the dept spectrum (in 1,1,2,2-tetrachloroethane-d2 at 110 °C) for poly(TCD-co-OC)s. Most of typical resonances were assigned according to those in poly(NBE-co-OC) (shown above) and poly(ethylene-co-TCD),26 and the spectra at various TCD contents (Figure 6a,c). Resonances at 49−53 ppm are ascribed to carbons in C5 and C10 positions in TCD,26 however, assignment of broad resonances in 54−56 ppm observed in the copolymers with high TCD contents [also observed in poly(NBE-co-OC)s with high NBE contents]22 seems to be difficult.22 Therefore, TCD contents were estimated by the following equation (use of total integration of carbons instead of specified resonances such as C5 and C10 in Figure 6) that is slightly different from that in poly(NBE-co-1-octene)s;27

Figure 4. Plots of glass transition temperature (Tg) vs TCD content (mol %) in poly(TCD-co-1-hexene)s (○), poly(TCD-co-1-octene)s (◇), poly(TCD-co-1-dodecene)s (◆). Plots of glass transition temperature (Tg) vs NBE content (mol %) in poly(NBE-co-1hexene)s (●) are also shown for comparison. Detailed data are shown in Table 4.

poly(TCD-co-DD)s < poly(TCD-co-OC)s < poly(TCD-coHX)s. It is clear that the Tg values in poly(TCD-co-HX)s [poly(TCD-co-OC)s, and poly(TCD-co-DD)s] are higher than those in poly(NBE-co-HX)s [poly(NBE-co-OC)s, and poly(NBE-co-DD)s] with the same α-olefin contents; these Tg values are also higher than those in the reported poly(DCP-coHX)s (DCP = dicyclopentadiene).19 Moreover, as shown in Figure 5, the TCD incorporation in the copolymerization by 2−MAO catalyst were not strongly

TCD (mol%) = [{Itotal − 4(I1B + I2B)}/12] /[{Itotal − 4(I1B + I2B)}/12 + 4(I1B + I2B)/8]

Although we could not assign all resonances, as suggested in the results by poly(NBE-co-α-olefin)s as well as plots of Tg with TCD contents, it seems likely in high certainty that the resultant copolymers are random copolymers (containing isolated, alternating, and repeated TCD incorporations). As shown in Figure 7, the resultant copolymers, poly(TCDco-HX)s and poly(TCD-co-OC), show high transparency as thin films, and the results should demonstrate a possibility that these polymers are promising materials with high transparency

Figure 5. Plots of TCD content (mol %) vs TCD/α-olefin feed molar ratios in TCD/α-olefin copolymerization by CpTiCl2(NCtBu2) (2)−MAO catalyst. α-Olefin: 1-hexene (○),1-octene (◇), and 1dodecene (◆). Detailed data are shown in Table 4.

affected by nature of α-olefin employed (HX, OC, and DD; number of methylene units in the side chain) under high TCD/

Table 5. Effect of Polymerization Time and Temperature in Copolymerization of TCD with 1-Hexene (HX) by CpTiCl2(N CtBu2) (2)−MAO Catalysta run

temp/°C

time/min

yield/mg

activityb

Mnc × 10−4

Mw/Mnc

Tgd/°C

46 87 88 89 90

25 25 25 50 70

15 35 55 15 15

143 174 187 127 83

2870 1490 1020 2550 1670

1.22 1.32 1.30 1.18 1.01

1.76 1.71 1.73 1.73 1.71

271 272 271 282 289

Conditions: complex 2 0.20 μmol in toluene 1.0 mL, TCD 2.0 mL, 1-hexene 0.56 mL (initial feed molar ratio of TCD:1-hexene =3.0:1.0), and MAO 1.5 mmol, 15 min, 25 °C. bActivity = kg-polymer/mol-Ti·h. cGPC data in THF vs polystyrene standards. dGlass transition temperature (Tg) measured by DSC thermogram.

a

G

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Figure 7. Plots of transmittance vs wavelength in (a) poly(TCD-co-1hexene) (run 54, TCD 55.5 mol %), (b) poly(TCD-co-1-hexene) (run 69, TCD 67.8 mol %), and (c) poly(TCD-co-1-hexene) (run 46, TCD 62.8 mol %). Detailed data are shown in Table 4.

Scheme 3. Copolymerization of norbornene (NBE) with 1octene in the presence of 1,7-octadiene (OD) using Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), C5H5 (2, Cp)] − MAO catalysts

Figure 6. (a) 13C NMR spectrum and (b) dept spectrum (in 1,1,2,2tetrachloroethane-d2 at 110 °C) for poly(TCD-co-1-octene) (run 71, TCD 35.0 mol %), and (c) 13C NMR spectrum for poly(TCD-co-1octene) (run 76, TCD 67.6 mol %). Detailed data are shown in Table 4.

as well as with high glass transition temperatures (Tg > 230 °C). 3. Copolymerization of Norbornene (NBE) with 1Octene (OC) in the Presence of 1,7-Octadiene by Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)]−MAO Catalysts: Introduction of Reactive Functionality. Copolymerizations of norbornene (NBE) with 1-octene (OC) using Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)]− MAO catalysts were conducted in the presence of 1,7-octadiene (OD) (Scheme 3). As demonstrated previously in polymerization of OC,28 or in ethylene copolymerization with OC28 or styrene29 in the presence of OD using aryloxo-modified halftitanocenes, Cp′TiCl2(O-2,6-iPr2C6H3) [Cp′ = C5Me5 (Cp*), t BuC5H4, 1,2,4-Me3C5H2], an introduction of reactive functionality (terminal olefin) into the polymer side chain by incorporation of OD would be expected by adopting this approach.30−32 The results are summarized in Table 6. It turned out that these polymerizations by 1,2−MAO catalysts afforded high molecular weight polymers with

unimodal molecular weight distributions [initial NBE/(OC + OD) feed molar ratios ca. 0.25]. As expected from the data in the NBE/OC copolymerization (Table 1), the Cp analogue (2) showed higher catalytic activities than the tBuC5H4 analogue (1); the activity by 2 seems decreasing upon increasing OD concentration charged, whereas the Mn value seems increasing upon increasing the OD concentration (runs 91−93 and 94− 96). The resultant polymers possessed uniform compositions confirmed by DSC thermograms (without cross-linking etc.). H

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Macromolecules Table 6. Copolymerization of Norbornene (NBE) with 1-Octene (OC) in the Presence of 1,7-Octadiene (OD) by Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)]−MAO Catalystsa run 91 92 93 94 95 96

catalyst (μmol) 1 1 1 2 2 2

(0.3) (0.2) (0.2) (0.05) (0.07) (0.08)

NBE/g

OC/mL

OD/mL

time/min

temp/°C

yield/mg

activityb

Mnc × 10−4

Mw/ Mnc

Tgd/°C

1.0 1.0 1.0 1.0 1.0 1.0

5.0 4.0 3.0 5.0 4.0 3.0

0 1.0 2.0 0 1.0 2.0

60 60 40 20 20 20

25 25 25 25 25 25

308 170 150 137 171 189

1210 850 1130 8240 7320 7070

5.60 8.24 9.52 3.33 4.12 5.69

1.70 1.85 1.90 1.63 1.75 1.80

61 58 49 99 75 75

Conditions: catalyst in 0.5 mL of toluene and MAO 1.0 mmol, 25 °C. bActivity = kg-polymer/mol-Ti·h. cGPC data in THF vs polystyrene standards. dGlass transition temperature measured by DSC thermogram. a

OD in certain degree (Figure 8a). In terms of synthesis of these polymers containing terminal olefinic double bond (Figure 8b,c), it is thus clear that 1 is more suited to the purpose although we are unsure about the reason why isomerization occurred only by 2. An introduction of reactive functionality (terminal olefinic double bond) into NBE/OC copolymers has thus been achieved by incorporation of OD by adopting this methodology.

Figure 8 shows selected NMR spectra in the resultant polymers. Resonances ascribed to olefinic double bonds were clearly observed in both 1H and 13C NMR spectra.22 However, the polymer prepared by 2 contains protons ascribed to internal olefins probably by subsequent isomerization after insertion of

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CONCLUDING REMARKS We have shown that efficient incorporations of norbornene (NBE), tetracyclododenece (TCD) have been achieved in the copolymerization with 1-hexene (HX), 1-octene (OC), and with 1-dodecene (DD) by using Cp′TiCl2(NCtBu2) [Cp′ = t BuC 5H 4 (1), Cp (2)]−MAO catalysts. The resultant copolymers possess rather high molecular weights, unimodal molecular weight distributions, and with uniform compositions confirmed by DSC thermograms. Moreover, an introduction of a reactive functionality (terminal olefinic double bond) into the polymer side chain has also been achieved, when these (NBE/ OC) copolymerizations were conducted in the presence of 1,7octadiene (OD). Contents in this study are summarized as follows. (1) The Cp analogue (2) showed both higher catalytic activity and more efficient NBE incorporation than the t BuC5H4 analogue (1) in NBE/α-olefin copolymerization; the NBE incorporation (Tg value in the resultant copolymer) by 2 were not affected by Al cocatalyst (MAO and MMAO) employed. Fairly good linear relationships between the glass transition temperature (Tg) and the NBE contents were observed irrespective of substituent on Cp′. The Tg value in poly(NBE-co-αolefin)s with the same α-olefin content was affected by length of (methylene) branching in the α-olefin employed. In contrast, relatively linear correlations between NBE contents in the copolymers and NBE/αolefin feed molar ratios were observed irrespective of kind of α-olefins (length of methylene units in the side chain). Random copolymers with various NBE contents as well as various (linear) branching could be thus prepared by varying the NBE/α-olefin feed molar ratios by adopting this catalysis. (2) The Cp analogue (2) showed both high catalytic activity and efficient TCD incorporation in the TCD/α-olefin copolymerization, whereas 1 showed the low activity, and [Me2Si(C5Me4)(NtBu)]TiCl2, ordinary metallocenes, [Et(indenyl)2]ZrCl2 or Cp2ZrCl2, showed the low catalytic activities affording oligomers. Good linear relationships between the Tg values and the TCD

Figure 8. (a) 1H NMR spectrum (in C6D6 at 25 °C) of poly(NBE-co1-octene-co-1,7-octadiene) prepared by CpTiCl2(NCtBu2) (2) − MAO catalyst (run 96), (b) 1H NMR spectrum (in C6D6 at 25 °C) and (c) 13C NMR spectrum (in 1,1,2,2-tetrachloroethane-d2 at 110 °C) of poly(NBE-co-1-octene-co-1,7-octadiene) prepared by (tBuC5H4)TiCl2(NCtBu2) (1)−MAO catalyst (run 93). Detailed data are shown in Table 6. I

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solution, and the spectra was measured at 110 °C. Molecular weights and the molecular weight distributions of the resultant polymers were measured by gel-permeation chromatography (GPC). HPLC grade THF was used for GPC and was degassed prior to use. GPC was performed at 40 °C on a Shimadzu SCL-10A using a RID-10A detector (Shimadzu Co. Ltd.) in THF (containing 0.03 wt % of 2,6-ditert-butyl-p-cresol, flow rate 1.0 mL/min). GPC columns (ShimPAC GPC-806, 804, and 802, 30 cm ×8.0 mm diameter, spherical porous gel made of styrene/divinylbenzene copolymer, ranging from 200 °C) has thus been achieved by adopting this catalysis. (3) Efficient incorporation of terminal olefinic double bonds into poly(NBE-co-1-octene)s has been demonstrated in the copolymerization in the presence of OD, and the t BuC5H4 analogue (1) seems more suitable than the Cp analogue (2) in terms of control of subsequent isomerization after OD incorporation. The method can be thus applied for synthesis of cyclic olefin copolymers containing reactive functionality for further modification. As described in the introductory, examples in synthesis of copolymers of NBE with α-olefins has been limited. Moreover, this is, as far as we know, the first examples for synthesis of TCD/α-olefin copolymers, in addition to preparation of a series of random poly(NBE-co-α-olefin)s with various NBE contents. These copolymers possess high glass transition temperature (thermal resistance) with high transparency and should show unique properties (humidity resistance etc.). It is thus highly expected that these polymers are promising materials as new class of cyclic olefin copolymers (COCs). We believe that the results demonstrated here is promising in terms of synthesis of new polymers, better understanding not only for the polymer design (combination of monomers), but also for the catalyst design for the efficient synthesis. We now will explore further possibilities for synthesis of new COCs that cannot be prepared by ordinary catalysts.

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EXPERIMENTAL SECTION

General Procedures. All experiments were carried out under a nitrogen atmosphere in a Vacuum Atmospheres drybox unless otherwise specified. All chemicals used were of reagent grade and were purified by the standard purification procedures. Anhydrous grade of toluene (Kanto Kagaku Co. Ltd.) was transferred into a bottle containing molecular sieves (mixture of 3A and 4A, 1/16, and 13X) in the drybox, and was used without further purification. Reagent grade norbornene (NBE) [Tokyo Chemical Industry (TCI) Co., Ltd.], tetracyclododecene (TCD) (Zeon corporation), 1-hexene (Kanto Chemical Co., Inc.), 1-octene (TCI Co., Ltd.), 1-dodecene (Kanto Chemical Co., Inc.) and 1,7-octadiene (TCI Co., Ltd.) were stored in bottles in the drybox and were passed through an alumina short column before use. Toluene (or n-hexane), AlMe3 (and AliBu3) in the commercially available methylaluminoxane (MAO) [PMAO-S, 9.5 wt % (Al) toluene solution, Tosoh Finechem Co.] and MMAO [modified MAO, methyl isobutyl aluminoxane, Me/iBu = 2.67; MMAO-3A-H, Tosoh Finechem Co.] were taken to dryness under reduced pressure (at ca. 50 °C for removing toluene, Me3Al, and then heated at >100 °C for 1 h for completion) in the drybox to give white solids. (tBuC5H4)TiCl2(NCtBu2) (1)33 and CpTiCl2(NCtBu2) (2)34 were prepared according to previous reports. [Me2Si(C5Me4)(NtBu)]TiCl2 (3, MCAT GmbH), and rac-[Et(indenyl)2]ZrCl2 (4, Strem Chemicals Inc.), and Cp2ZrCl2 (5, Aldrich) were used as received. All 1H and 13C NMR spectra were recorded on a Bruker AV 500 spectrometer (500.13 MHz for 1H; 125.77 MHz for 13C), and all chemical shifts are given in ppm and are referred to SiMe4. 13C NMR spectra for the resultant polymers were recorded with proton decoupling, and the pulse interval was 5.2 s, the acquisition time was 0.8 s, the pulse angle was 90°, and the number of transients accumulated was about 6000. The copolymer samples for analysis were prepared by dissolving the polymers in 1,1,2,2-tetrachloroethane-d2

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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.macromol.5b02176. Additional data in copolymerization of tetracyclododecene (TCD) with 1-hexene (HX), 1-octene (OC), 1dodecene (DD) by Cp′TiCl2(NCtBu2) [Cp′ = t BuC5H4 (1), Cp (2)], [Me2Si(C5Me4)(NtBu)]TiCl2 (3), [Et(indenyl)2]ZrCl2 (4), Cp2ZrCl2 (5)−MAO catalysts, selected NMR spectra for copolymers, poly(NBE-co-α-olefin)s, poly(TCD-co-α-olefin)s and poly(NBE-co-1-octene-co-1,7-octadiene), estimation of TCD contents, and selected DSC thermograms of copolymers (PDF)

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AUTHOR INFORMATION

Corresponding Author

*(K.N.) Telephone and fax: +81-42-677-2547. E-mail: [email protected]. Notes

The authors declare no competing financial interest. J

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(6) Recent review article: (a) Bochmann, M. The Chemistry of Catalyst Activation: The case of Group 4 Polymerization Catalyst. Organometallics 2010, 29, 4711. Related references are cited therein. (b) Kaminsky, W. Discovery of Methylaluminoxane as Cocatalyst for Olefin Polymerization. Macromolecules 2012, 45, 3289. (7) (a) Kaminsky, W. Angew. Makromol. Chem. 1994, 223, 101. (b) Cherdron, H.; Brekner, M.-J.; Osan, F. Angew. Makromol. Chem. 1994, 223, 121. (c) Kaminsky, W.; Beulich, I.; Arndt-Rosenau, M. Macromol. Symp. 2001, 173, 211. (d) Dragutan, V.; Streck, R. Catalytic Polymerisation of Cycloolefins; Studies in Surface Science and Catalysis 131, Elsevier: Amsterdam, 2000. (e) Tritto, I.; Boggioni, L.; Ferro, D. R. Coord. Chem. Rev. 2006, 250, 212. (f) Nomura, K. Chin. J. Polym. Sci. 2008, 26, 513. (g) Li, X.; Hou, Z. Coord. Chem. Rev. 2008, 252, 1842 References are cited therein.. (8) For example: (a) Ruchatz, D.; Fink, G. Macromolecules 1998, 31, 4669;(b) 1998, 31, 4674;(c) 1998, 31, 4681;(d) 1998, 31, 4684. (e) Provasoli, A.; Ferro, D. R.; Tritto, I.; Boggioni, L. Macromolecules 1999, 32, 6697. (f) Tritto, I.; Marestin, C.; Boggioni, L.; Zetta, L.; Provasoli, A.; Ferro, D. R. Macromolecules 2000, 33, 8931. (g) Tritto, I.; Marestin, C.; Boggioni, L.; Sacchi, M. C.; Brintzinger, H.-H.; Ferro, D. R. Macromolecules 2001, 34, 5770. (h) Tritto, I.; Boggioni, L.; Jansen, J. C.; Thorshaug, K.; Sacchi, M. C.; Ferro, D. R. Macromolecules 2002, 35, 616. (9) For example: (a) Harrington, B. A.; Crowther, D. J. J. Mol. Catal. A: Chem. 1998, 128, 79. (b) McKnight, A. L.; Waymouth, R. M. Macromolecules 1999, 32, 2816. (c) Thorshaug, K.; Mendichi, R.; Boggioni, L.; Tritto, I.; Trinkle, S.; Friedrich, C.; Mülhaupt, R. Macromolecules 2002, 35, 2903. (d) Hasan, T.; Ikeda, T.; Shiono, T. Macromolecules 2004, 37, 8503. (10) (a) Nomura, K.; Tsubota, M.; Fujiki, M. Macromolecules 2003, 36, 3797. (b) Wang, W.; Tanaka, T.; Tsubota, M.; Fujiki, M.; Yamanaka, S.; Nomura, K. Adv. Synth. Catal. 2005, 347, 433. (c) Nomura, K.; Wang, W.; Fujiki, M.; Liu, J. Chem. Commun. 2006, 2659. (d) Nomura, K.; Fukuda, H.; Katao, S.; Fujiki, M.; Kim, H. J.; Kim, D. H.; Saeed, I. Macromolecules 2011, 44, 1986. (e) Apisuk, W.; Trambitas, A. G.; Kitiyanan, B.; Tamm, M.; Nomura, K. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2575. (11) For example: (a) Altamura, P.; Grassi, A. Macromolecules 2001, 34, 9197. (b) Yoshida, Y.; Saito, J.; Mitani, M.; Takagi, Y.; Matsui, S.; Ishii, S.; Nakano, T.; Kashiwa, N.; Fujita, T. Chem. Commun. 2002, 1298. (c) Yoshida, Y.; Mohri, J.; Ishii, S.; Mitani, M.; Saito, J.; Matsui, S.; Makio, H.; Nakano, T.; Tanaka, H.; Onda, M.; Yamamoto, Y.; Mizuno, A.; Fujita, T. J. Am. Chem. Soc. 2004, 126, 12023. (d) Li, X.F.; Dai, K.; Ye, W.-P.; Pan, L.; Li, Y.-S. Organometallics 2004, 23, 1223. (12) For example: http://www.topas.com/products/topas-cocpolymers. (13) (a) Henschke, O.; Köller, F.; Arnold, M. Copolymerization of propylene with norbornene (NBE) by linked metallocenes,. Macromol. Rapid Commun. 1997, 18, 617. (b) Boggioni, L.; Bertini, F.; Zannoni, G.; Tritto, I.; Carbone, P.; Ragazzi, M.; Ferro, D. R. Macromolecules 2003, 36, 882. (c) Boggioni, L.; Tritto, I.; Ragazzi, M.; Carbone, P.; Ferro, D. R. Macromol. Symp. 2004, 218, 39. (d) Jung, H. Y.; Hong, S.D.; Jung, M. W.; Lee, H.; Park, Y.-W. Polyhedron 2005, 24, 1269. (e) Vanegas, M. E.; Quijada, R.; Galland, G. B. Results concerning NBE with 1-hexene, 1-octene using [H2C(Me2C5H2)2]ZrCl2 catalyst. Polymer 2010, 51, 4627. (14) Hasan, T.; Ikeda, T.; Shiono, T. Copolymerization of NBE with propylene by [Me2Si(fluorenyl)(NtBu)]TiMe2. Macromolecules 2005, 38, 1071. (15) Copolymerization of NBE with 1-hexene, 1-octene, and with 1decene using linked-half-titanocenes (containing fluorenyl fragment): (a) Hasan, T.; Ikeda, T.; Shiono, T. Macromolecules 2005, 38, 1071. (b) Cai, Z.; Nakayama, Y.; Shiono, T. Macromolecules 2006, 39, 2031. (c) Shiono, T.; Sugimoto, M.; Hasan, T.; Cai, Z.; Ikeda, T. Macromolecules 2008, 41, 8292. (d) Cai, Z.; Harada, R.; Nakayama, Y.; Shiono, T. Macromolecules 2010, 43, 4527. (16) Living NBE homo polymerization by [Me2Si(fluorenyl)(NtBu)] TiMe2: (a) Hasan, T.; Nishii, K.; Shiono, T.; Ikeda, T. Macromolecules

ACKNOWLEDGMENTS The present research is partly supported by Grant-in-Aid for Scientific Research (B) from the Japan Society for the Promotion of Science (JSPS, No. 15H03812). W.Z. expresses his thanks to Tokyo metropolitan government (Asian Human Resources Fund) for predoctoral fellowship, and the project was partly supported by the advanced research program (Tokyo metropolitan government). The authors also express their thanks to Tosoh Finechem Co. for donating MAO (TMAO), Zeon Corp. for donating tetracycylododecene (TCD) sample, and Polyplastics Co. for discussion in measurement of NMR spectra in poly(NBE-co-α-olefin)s. W.Z. expresses her heartfelt thanks to Dr. Wannida Apisuk (Tokyo Metropolitan University, TMU) for helpful experimental assistance as well as fruitful discussions, and to Mr. Kensaku Fujii (Zeon Corp.) for measurement of transmittance of polymer films. Authors express their thanks to Profs. A. Inagaki, K. Tsutsumi, and Prof. S. Komiya (TMU) for discussions.

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REFERENCES

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Article

Macromolecules 2002, 35, 8933. (b) Hasan, T.; Ikeda, T.; Shiono, T. Macromolecules 2004, 37, 7432. (17) Living propylene polymerization by [Me2Si(fluorenyl)(NtBu)] TiMe2: Hasan, T.; Ioku, A.; Nishii, K.; Shiono, T.; Ikeda, T. Macromolecules 2001, 34, 3142. (18) These results were partly presented at the 8th International Symposium on High-Tech Polymer Materials (HTPM = VIII), Beijing, China, July, 2014. (19) Cooligomerization of 1-hexene and dicyclopentadiene using CpSc catalyst: Li, X.; Nishiura, M.; Mori, K.; Mashiko, T.; Hou, Z. Chem. Commun. 2007, 4137 Oligomers (Mn = 1300−2200) with Tg of 9−210 °C were obtained, but showed low catalytic activities (3.4−3.9 kgpolymer/ mol-Sc·h).. (20) These results were partly presented at The Seventh International Symposium on Engineering Plastics (EP’2015), Xining, China, August, 2015; International Conference on Organometallic Chemistry (ICOMC), Sapporo, July, 2014; Advances in Polyolef ins 2015, Santa Rosa, CA, September, 2015. (21) Liu, J.; Nomura, K. Adv. Synth. Catal. 2007, 349, 2235. (22) Selected NMR spectra and DSC thermograms in the resultant copolymers are shown in the Supporting Information. (23) Nomura, K.; Fujita, K.; Fujiki, M. Catal. Commun. 2004, 5, 513. (24) For example: (a) Suhm, J.; Schneider, M. J.; Mülhaupt, R. J. J. Polym. Sci., Part A: Polym. Chem. 1997, 35, 735. (b) Suhm, J.; Schneider, M. J.; Mülhaupt, R. J. Mol. Catal. A: Chem. 1998, 128, 215. (25) Additional data in copolymerization of TCD with 1-hexene (HX), 1-octene (OC), 1-dodecene (DD) by Cp′TiCl2(NCtBu2) [Cp′ = tBuC5H4 (1), Cp (2)], [Me2Si(C5Me4)(NtBu)]TiCl2 (3), [Et(indenyl)2]ZrCl2 (4), Cp2ZrCl2 (5) - MAO catalysts are shown in the Supporting Information. (26) Shin, J. Y.; Park, J. Y.; Liu, C.; He, J.; Kim, S. C. Pure Appl. Chem. 2005, 77, 801. (27) Comparison in estimations of TCD contents (two methods) are introduced in the Supporting Information. Present method (use of total integration of carbons instead of specified carbons, C5, C10) seems better especially for the copolymers because we could not assign all resonances observed in 49 → 56 ppm, as described in the text. (28) Nomura, K.; Liu, J.; Fujiki, M.; Takemoto, A. J. Am. Chem. Soc. 2007, 129, 14170. (29) Apisuk, W.; Nomura, K. Macromol. Chem. Phys. 2014, 215, 1785. (30) For related examples, (a) Itagaki, K.; Fujiki, M.; Nomura, K. Macromolecules 2007, 40, 6489. (b) Itagaki, K.; Nomura, K. Macromolecules 2009, 42, 5097. (c) Apisuk, W.; Kitiyanan, B.; Kim, H.-J.; Kim, D.-H.; Nomura, K. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2581. (31) (a) Chung, T. C. Functionalization of Polyolefins; Academic Press: San Diego, CA, 2002. (b) Chung, T. C. Prog. Polym. Sci. 2002, 27, 39. (c) Chung, T. C. M. Green Sustainable Chem. 2012, 2, 29. (32) (a) Nomura, K.; Kitiyanan, B. Curr. Org. Synth. 2008, 5, 217. (b) Nomura, K. Yuki Gosei Kagaku Kyokaishi 2010, 68, 1150. (c) Apisuk, W.; Tsutsumi, K.; Kim, H.-J.; Kim, D.-H.; Nomura, K. Green Sustainable Chem. 2014, 4, 133. (33) Nomura, K.; Fujita, K.; Fujiki, M. J. Mol. Catal. A: Chem. 2004, 220, 133. (34) Zhang, S.; Piers, W. E.; Gao, X.; Parvez, M. J. Am. Chem. Soc. 2000, 122, 5499.

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DOI: 10.1021/acs.macromol.5b02176 Macromolecules XXXX, XXX, XXX−XXX