Alkane-Soluble Bis[tris(alkylphenyl)carbenium] Diborate Cocatalyst for Olefin Polymerizations
Alkane-Soluble Bis[tris(alkylphenyl)carbenium] Diborate Cocatalyst for Olefin Polymerizations
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DOI：
10.1021/acscatal.2c01676
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发表时间：
2022-06-13
期刊：
影响因子：
12.9
通讯作者：
Marks, Tobin J.
中科院分区：
文献类型：
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作者：
Gao, Yanshan;Christianson, Matthew D.;Marks, Tobin J.
双核双阴离子助催化剂可以将阳离子活性金属中心紧密地结合在一起，研究烯烃聚合催化中的中心-中心链结协同效应。先前报道的双核二硼酸盐助催化剂（Ph 3C+）（2）[1，4-（C6 F5）（3）BC 6 F4 B（C6 F5）（3）]（2-）（B-2，B-H）在烷烃和芳族溶剂中溶解性差，并且需要不期望的卤代芳族添加剂来完全溶解它以进行有效的烯烃聚合。本文中，两种双核二硼酸盐基助催化剂（Ar 3C+）（2）[1，4-（C6 F5）（3）BC 6 F4 B（C6 F5）（3）]（2-）（B-2，B-t-Bu; Ar = 4-t-Bu-C6 H 4-; B-2，B-正辛基; Ar = 4-正辛基-C6 H 4-），并通过多核NMR谱、密度泛函理论计算和B-2的单晶衍射进行了表征，B-t-Bu中心点B-2，B-正辛基在低极性溶剂如甲苯和甲基环己烷（MeCy）中表现出良好的溶解性，使得能够研究（μ-CH2CH2 -3，3 '）{（η（5）-茚基）[1-（MeSi）-Si-2（（BuN）-Bu-t）]（ZrMe+）（2）[EBICGC（ZrMe+）（2）]-催化的乙烯在极性递减的溶剂体系中的均聚和共聚（甲苯/二氟苯->甲苯-> MeCy）。产物M（w）s是双峰的并且对上述溶剂进展敏感，其中对于乙烯均聚，高M-w分数（wt %）分别从41 -> 92 -> 100%增加，对于乙烯+1-己烯共聚，高M-w分数（wt %）分别从15 -> 53 -> 93%增加。在规模化/工业化高温、高压操作条件下，同样的可溶性双核二硼酸盐是活性烯烃共聚助催化剂，得到高分子M（w）s和相似的分散度D。
Binuclear dianionic cocatalysts can bring cationic active metal centers into close proximity to study center-center enchainment cooperativity effects in olefin polymerization catalysis. The previously reported binuclear diborate cocatalyst, (Ph3C+)(2)[1,4-(C6F5)(3)BC6F4B(C6F5)(3)](2-) (B-2,B-H), is poorly soluble in alkane and aromatic solvents and requires undesirable haloaromatic additives to fully solubilize it for efficient olefin polymerizations. Here, two binuclear diborate-based cocatalysts, (Ar3C+)(2)[1,4-(C6F5)(3)BC6F4B(C6F5)(3)](2-) (B-2,B-t-Bu; Ar = 4-t-Bu-C6H4-; B-2,B-n-octyl; Ar = 4-n-octyl-C6H4-), are synthesized and characterized by multinuclear NMR spectroscopy, density functional theory computation, and by single-crystal diffraction for B-2,B-t-Bu center dot B-2,B-n-octyl exhibits good solubility in low-polarity solvents such as toluene and methylcyclohexane (MeCy), enabling the study of (mu-CH2CH2-3,3'){(eta(5)-indenyl)[1-(MeSi)-Si-2((BuN)-Bu-t)](ZrMe+)(2) [EBICGC(ZrMe+)(2)]-catalyzed ethylene homo- and co-polymerizations in solvent systems of decreasing polarity (toluene/difluorobenzene -> toluene -> MeCy). Product M(w)s are bimodal and sensitive to the above solvent progression, with the high-M-w fraction (wt %) increasing from 41 -> 92 -> 100%, respectively, for ethylene homopolymerization, and from 15 -> 53 -> 93%, respectively, for ethylene + 1-hexene copolymerization. Under scaled/industrial high temperature, higher pressure operating conditions, the same soluble binuclear diborate is an active olefin copolymerization cocatalyst, giving high polymer M(w)s and similar dispersity, D.