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Acta Chimica Sinica >

2020 , Vol. 78 >Issue 8: 778 - 787

DOI: https://doi.org/10.6023/A20030092

Article

Ethylene-Bridged Multi-Substituted Indenyl-Fluorenyl Zirconocene and Hafnocene Complexes: Synthesis, Structure and Catalytic Behavior for Propylene Selective Oligomerization

  • Zhang Lei ,
  • Ma Haiyan
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  • Laboratory of Organometallic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237

Received date: 2020-03-27

  Online published: 2020-06-16

Supported by

Project supported by the National Natural Science Foundation of China (No. 21274041).

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Abstract

In metallocene-mediated propylene polymerization, β-methyl elimination (β-Me elimination) is considered as the key chain-release step for obtaining allyl-terminated products, which are highly preferred as macro(co)monomers or building blocks for preparing novel polymers. However, for most metallocene catalysts the transfer of a β-methyl is instinctively less favored due to its steric and electronic disadvantages. Up to date, very few cases have been found to be efficient for triggering selective β-methyl elimination. In this work, a series of novel ansa-metallocene complexes, ansa-C2H4-{2-Me-3-Bn- 5,6-[1,3-(CH2)3]Ind}(Flu)ZrCl2 (C1), ansa-C2H4-{2-Me-3-Bn-5,6-[1,3-(CH2)3]Ind}(2,7-tBu2-Flu)ZrCl2 (C2), ansa-C2H4-{2-Me-3-Bn-5,6-[1,3-(CH2)3]Ind}(3,6-tBu2-Flu)ZrCl2 (C3) and ansa-C2H4-{2-Me-3-Bn-5,6-[1,3-(CH2)3]Ind}(Flu)HfCl2 (C4), were synthesized via the reaction of the dilithium salts of the corresponding proligand with 1 equiv. of ZrCl4 or HfCl4 in Et2O. All complexes were characterized by 1H NMR, 13C NMR and elemental analysis. The molecular structures of complexes C1, C2, and C3 were further determined via X-ray diffraction method. In the solid state, these complexes adopted an indenyl-backward orientation with rotation angles (RA: the orientation of the indenyl ring with respect to the fluorenyl ring) ranging from －11.30° to －17.07°. Upon activation with modified methylaluminoxane (MMAO) or AliBu3/ [Ph3C][B(C6F5)4] (TIBA/TrB), all these complexes exhibited moderate to high activities for propylene oligomerization at 40～100 ℃, affording propylene oligomers with both allyl and vinylidene chain-ends, which arised from β-Me elimination and β-H eliminations respectively. The methyl group at the 2-position of the indenyl ring turned out to have negative effects on both catalytic activity and β-Me elimination selectivity. Zirconocene complex C1 polymerized propylene to give oligomers with 40%～52% allyl chain-ends. However, further modification of the fluorenyl moiety allowed a great improvement in β-Me elimination selectivity. At 40～100 ℃, zirconocene complexes C2 and C3 bearing a 2,7- or 3,6-di-tert-butyl- substituted fluorenyl moiety showed significantly higher β-Me elimination selectivities (C2, 81%～86%; C3, 68%～77%), affording propylene oligomers (Mn 400～4500 g·mol－1) with allyl-dominant chain-ends. Moreover the substitution pattern of the fluorenyl moiety also substantially influenced the catalytic activities. The incorporation of an electron-donating 2,7-di-tert-butyl groups on the fluorenyl moiety led to notably increased catalytic activities of complex C2 at higher temper- atures above 60 ℃, while complex C3 bearing a 3,6-di-tert-butyl-substituted fluorenyl moiety showed lowest activities among the zirconocene series due to its overcrowded coordination sites. Compared with its zirconocene analogue, the hafnocene complex C4 activated with TIBA/TrB proved to be even more selective toward β-Me elimination, and meanwhile gave products with much lower molecular weights. At 100 ℃, the hafnocene system mainly oligomerized propylene to dimers and trimers. Studies on the dependence of the product molecular weight and the chain-release selectivity on monomer concentration suggested that both β-Me and β-H elimination involved in these systems mainly operate in a bimolecular pathway.

Key words： metallocene catalyst; propylene oligomerization; allyl chain-end; β-methyl elimination

Cite this article

Zhang Lei , Ma Haiyan . Ethylene-Bridged Multi-Substituted Indenyl-Fluorenyl Zirconocene and Hafnocene Complexes: Synthesis, Structure and Catalytic Behavior for Propylene Selective Oligomerization[J]. Acta Chimica Sinica, 2020 , 78(8) : 778 -787 . DOI: 10.6023/A20030092

References

[1] O’Reilly, M. E.; Dutta, S.; Veige, A. S. Chem. Rev. 2016, 116, 8105.
[2] Janiak, C. Coord. Chem. Rev. 2006, 250, 66.
[3] Janiak, C.; Blank, F. Macromol. Symp. 2006, 236, 14.
[4] Janiak, C.; Lange, K. C. H.; Marquardt, P.; Krüger, R.-P.; Hanselmann, R. Macromol. Chem. Phys. 2002, 203, 129.
[5] Resconi, L.; Camurati, I.; Sudmeijer, O. Top. Catal. 1999, 7, 145.
[6] Chen, Z.; Mao, Y.; Cao, Y.; Liang, S.; Song, S.; Ni, C.; Liu, Z.; Ye, X.; Shen, A.; Zhu, H. Chin. J. Org. Chem. 2018, 38, 2937. (陈志康, 毛远洪, 曹育才, 梁胜彪, 宋莎, 倪晨, 刘振宇, 叶晓峰, 沈安, 朱红平, 有机化学, 2018, 38, 2937.)
[7] Tsou, A. H.; López-Barrón, C. R.; Jiang, P.; Crowther, D. J.; Zeng, Y. Polymer 2016, 104, 72.
[8] Ohtaki, H.; Deplace, F.; Vo, G. D.; LaPointe, A. M.; Shimizu, F.; Sugano, T.; Kramer, E. J.; Fredrickson, G. H.; Coates, G. W. Macromolecules 2015, 48, 7489.
[9] Schöbel, A.; Lanzinger, D.; Rieger, B. Organometallics 2013, 32, 427.
[10] Rose, J. M.; Mourey, T. H.; Slater, L. A.; Keresztes, I.; Fetters, L. J.; Coates, G. W. Macromolecules 2008, 41, 559.
[11] Weng, W.; Markel, E. J.; Peacock, A. J.; Dekmezian, A. H. Macromol. Rapid Commun. 2001, 22, 1488.
[12] Markel, E. Macromolecules 2000, 33, 8541.
[13] Watson, P. L.; Roe, D. C. J. Am. Chem. Soc. 1982, 104, 6471.
[14] Eshuis, J. J. W.; Tan, Y. Y.; Teuben, J. H.; Renkema, J. J. Mol. Catal. 1990, 62, 277.
[15] Eshuis, J. J. W.; Tan, Y. Y.; Meetsma, A.; Teuben, J. H.; Renkema, J.; Evens, G. G. Organometallics 1992, 11, 362.
[16] Resconi, L.; Piemontesi, F.; Franciscono, G.; Abis, L.; Fiorani, T. J. Am. Chem. Soc. 1992, 114, 1025.
[17] Zhang, L.; Ma, H. Chin. J. Polym. Sci. 2019, 37, 578.
[18] Machat, M. R.; Lanzinger, D.; Pöthig, A.; Rieger, B. Organometallics 2017, 36, 399.
[19] Bader, M.; Marquet, N.; Kirillov, E.; Roisnel, T.; Razavi, A.; Lhost, O.; Carpentier, J.-F. Organometallics 2012, 31, 8375.
[20] Suzuki, Y.; Yasumoyo, T.; Mashima, K.; Okuda, J. J. Am. Chem. Soc. 2006, 128, 13017.
[21] Moscardi, G.; Resconi, L.; Cavallo, L. Organometallics 2001, 20, 1918.
[22] Weng, W.; Markel, E. J.; Dekmezian, A. H. Macromol. Rapid Commun. 2000, 21, 1103.
[23] Resconi, L.; Piemontesi, F.; Camurati, I.; Sudmeijer, O.; Nifant’ev, I. E.; Ivchenko, P. V.; Kuz’mina, L. G. J. Am. Chem. Soc. 1998, 120, 2308.
[24] Resconi, L.; Jones, R. L.; Rheingold, A. L.; Yap, G. P. A. Organometallics 1996, 15, 998.
[25] Wang, Y.; Huang, W.; Ma, H.; Huang, J. Polyhedron 2014, 76, 81.
[26] Deisenhofer, S.; Feifel, T.; Kukral, J.; Klinga, M.; Leskela, M.; Rieger, B. Organometallics 2003, 22, 3495.
[27] Dietrich, U.; Hackmann, M.; Rieger, B.; Klinga, M.; Leskela, M. J. Am. Chem. Soc. 1999, 121, 4348.
[28] Cobzaru, C.; Deisenhofer, S.; Harley, A.; Troll, C.; Hild, S.; Rieger, B. Macromol. Chem. Phys. 2005, 206, 1231.
[29] Rieger, B.; Jany, G.; Fawzi, R.; Steimann, M. Organometallics 1994, 13, 647.
[30] Alt, H. G.; Jung, M. J. Organomet. Chem. 1999, 580, 1.
[31] Thomas, E. J.; Rausch, M. D.; Chien, J. C. W. Organometallics 2000, 19, 4077.
[32] Thomas, E. J.; Chien, J. C. W.; Rausch, M. D. Macromolecules 2000, 33, 1546.
[33] Schmid, M. A.; Alt, H. G.; Milius, W. J. Organomet. Chem. 1995, 501, 101.
[34] Spaleck, W.; Antberg, M.; Rohrmann, J.; Winter, A.; Bachmann, B.; Kiprof, P.; Behm, J.; Herrmann, W. A. Angew. Chem., Int. Ed. Engl. 1992, 31, 1347.
[35] Chen, E. Y.-X.; Marks, T. J. Chem. Rev. 2000, 100, 1391.
[36] Busico, V.; Cipullo, R.; Cutillo, F.; Friederichs, N.; Ronca, S.; Wang, B. J. Am. Chem. Soc. 2003, 125, 12402.
[37] Stapleton, R. A.; Galan, B. R.; Collins, S.; Simons, R. S.; Garrison, J. C.; Youngs, W. J. J. Am. Chem. Soc. 2003, 125, 9246.
[38] Busico, V.; Cipullo, R.; Pellecchia, R.; Talarico, G.; Razavi, A. Macromolecules 2009, 42, 1789.
[39] Mise, T.; Kageyama, A.; Miya, S.; Yamazaki, H. Chem. Lett. 1991, 1525.
[40] Busico, V.; Brita, D.; Caporaso, L.; Cipullo, R.; Vacatello, M. Macromolecules 1997, 30, 3971.
[41] Stehling, U.; Diebold, J.; Kirsten, R.; Roell, W.; Brintzinger, H. H.; Juengling, S.; Muelhaupt, R.; Langhauser, F. Organometallics 1994, 13, 964.
[42] Aitola, E.; Surakka, M.; Repo, T.; Linnolahti, M.; Lappalainen, K.; Kervinen, K.; Klinga, M.; Pakkanen, T.; Leskela, M. J. Organomet. Chem. 2005, 690, 773.
[43] Perumattam, J.; Shao, C.; Confer, W. L. Synthesis 1994, 1181.
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