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首页> 外文期刊>Organometallics >Controlled Benzylation of alpha-Diimine Ligands Bound to Zirconium and Hafnium: An Alternative Method for Preparing Mono- and Bis(amido)M(CH2Ph)(n) (n=2, 3) Complexes as Catalyst Precursors for Isospecific Polymerization of alpha-Olefins
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Controlled Benzylation of alpha-Diimine Ligands Bound to Zirconium and Hafnium: An Alternative Method for Preparing Mono- and Bis(amido)M(CH2Ph)(n) (n=2, 3) Complexes as Catalyst Precursors for Isospecific Polymerization of alpha-Olefins

机译：绑定到锆和Ha的α-二胺配体的受控苯甲酸酯化：制备单和双（酰胺基）M（CH2Ph）（n）（n = 2，3）配合物作为α-烯烃同等聚合的催化剂前体的另一种方法

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摘要

Reactions of M(CH2Ph)(4)(M = Zr, Hf) with various alpha-diimine ligands afforded amido-imino or diamido complexes through intramolecular benzylation of the C=N bonds of the ligands. Selective benzylation of alpha-diimine ligands, i.e., single- and double-benzylation, was accomplished by varying the substituent on the nitrogen atom of the imine moiety or the ligand backbone. Kinetic analysis of the second benzylation step indicated that the benzyl group migrated from the metal center to the C=N moiety via an ordered four-center transition state (Delta S-double dagger = -3(4) eu for 3a; -5(9) eu for 5b). Upon activation with B(C6F5)(3) or [Ph3C] [B(C6F5)(4)], amido-imino (3, 6) and diamido (2, 4) complexes became active catalysts for 1-hexene polymerization, and the resulting poly(1-hexene)s had moderate isotacticity ([mmmm], up to 90%). Polymerization of vinylcyclohexane was also catalyzed with moderate activity to give highly isotactic poly(vinylcyclohexane) ([mmmm] > 95%) via a chain-end control mechanism.
机译：M（CH2Ph）（4）（M = Zr，Hf）与各种α-二亚胺配体的反应通过配体的C = N键的分子内苄基化作用提供酰胺基-亚氨基或二酰胺基配合物。 α-二亚胺配体的选择性苄基化，即单和双苄基化，是通过改变亚胺部分或配体主链的氮原子上的取代基来实现的。第二个苄基化步骤的动力学分析表明，苄基通过有序的四中心过渡态从金属中心迁移到C = N部分（对于3a，Delta S-双匕首= -3（4）eu; -5（ 9）欧盟要求5b）。在用B（C6F5）（3）或[Ph3C] [B（C6F5）（4）活化后，酰胺基亚氨基（3，6）和二酰胺基（2，4）络合物成为1-己烯聚合的活性催化剂，并且所得的聚（1-己烯）具有中等的等规度（[mmmm]，最高为90％）。乙烯基环己烷的聚合也以中等活性被催化，以通过链端控制机制得到高度等规的聚（乙烯基环己烷）（[mmmm]> 95％）。

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