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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >New bis(aryloxy)-Ti(iv) complexes and their use for the selective dimerization of ethylene to 1-butene
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New bis(aryloxy)-Ti(iv) complexes and their use for the selective dimerization of ethylene to 1-butene

机译：新的双（芳氧基）-Ti（iv）配合物及其在乙烯选择性二聚为1-丁烯中的用途

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摘要

New titanium complexes of general formula [(ArO) _nTi(Oi-Pr) _((4-n))] were synthesized and used as pre-catalysts for the selective dimerization of ethylene to 1-butene. The complexes were prepared in cyclohexane using [Ti(Oi-Pr) _4] and one or two equivalents of the corresponding phenols (ArOH) at room temperature. In this work, both monodentate and chelating phenols were evaluated. For alkyl-substituted phenols, it was demonstrated that large steric hindrance at both ortho and ortho′ positions selectively yielded the mono-substituted complexes [(ArO)Ti(Oi-Pr) _3]. Substitution at only one of the ortho positions allowed both the mono- and the di-substituted Ti complexes to be isolated. When a heteroatom was introduced on the phenol backbone, di-substitution systematically occurred except with phenols presenting a hemilabile -CH _2NR _2 group at the ortho position. Upon activation with 3 equiv. of AlEt _3 at 20 bar and 60 °C, all the complexes selectively dimerized ethylene to 1-butene (>86% of butenes among which 99% of 1-butene). An increase of the steric bulk at the ortho position of the ligand or the introduction of a functional group led to decreased activity compared to [Ti(Oi-Pr) _4].
机译：合成了通式为[（ArO）_nTi（Oi-Pr）_（（4-n））]的新型钛配合物，并将其用作乙烯选择性二聚为1-丁烯的预催化剂。在室温下，使用[Ti（Oi-Pr）_4]和一或两当量的相应酚（ArOH）在环己烷中制备配合物。在这项工作中，评估了单齿酚和螯合酚。对于烷基取代的苯酚，已证明在邻位和邻位的大位阻选择性地产生了单取代的配合物[（ArO）Ti（Oi-Pr）_3]。仅在邻位之一上的取代允许分离单取代的钛配合物和双取代的钛配合物。当杂原子引入酚主链上时，系统发生了双取代反应，只是酚在邻位存在一个半不稳定的-CH _2NR _2基团。激活3当量后。在20 bar和60°C下，AlEt _3的所有配合物都将乙烯选择性二聚为1-丁烯（> 86％的丁烯，其中99％的1-丁烯）。与[Ti（Oi-Pr）_4]相比，配体邻位的空间体积增加或官能团的引入导致活性降低。

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