The synthesis and characterization of three complexes of the type (N‐(3‐tert‐butylsalicylidene)‐R)₂TiCl₂ [R=2,6‐difluorophenyl 1, R=2,6‐dimethylphenyl 2, R=phenyl 3] is reported and compared with the highly active R=2,3,4,5,6,–pentafluorophenyl 4. The complexes were tested for ethylene polymerization when activated with different co‐catalysts, giving high catalytic activity when activated with methylaluminoxane for complexes 3 and 4. Complex 3 is the only catalyst to be inactive when activated with diethylaluminum chloride. Unexpectedly, for complexes 1 and 2, no catalytic activity is recorded when butylated hydroxytoluene in methylaluminoxane is used to remove the trimethylaluminum, while the catalytic activity for complex 3 is retained. NMR study on the activation of the four complexes in the presence of common alkyl aluminum co‐catalysts suggests the formation of Ti(III) species in the presence of tri‐iso‐butylaluminum, and also the formation of NR−CH₂ (R: −Al(CH₂CH(CH₃)₂)₂) bond from the N=C−H bond of the ligand explaining the absence of catalytic activity. Density functional theory calculations using B3LYP and a combination of basis sets (6‐31+G and cc‐pVTZ) were performed on the catalyst precursors and the activated species showing insights into the frontier orbitals, localizing the LUMO on the imino bond elucidating their reactivity. Mulliken charges are also reported and an unexpected relationship between the nitrogen on the ligands and the molecular weight is observed.

中文翻译：

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苯氧亚胺钛配合物的结构修饰和烷基铝化合物的活化研究

三种类型（N-（3-叔丁基水杨基）-R）₂ TiCl ₂ [R = 2,6-二氟苯基1，R = 2,6-二甲基苯基2，R =苯基3 ]的配合物的合成与表征据报道并与高活性R = 2,3,4,5,6，-五氟苯基4进行比较。当用不同的助催化剂活化时，对配合物进行了乙烯聚合反应的测试，当用甲基铝氧烷活化配合物3和4时，该配合物具有很高的催化活性。当用氯化二乙基铝活化时，配合物3是唯一失活的催化剂。出乎意料的，对于复合物1和2，当使用甲基铝氧烷中的丁基化羟基甲苯除去三甲基铝时，没有记录催化活性，而保留了配合物3的催化活性。在普通烷基铝助催化剂存在下对四种络合物活化的NMR研究表明，在三异丁基铝存在下会形成Ti（III）物种，并且还会形成NR-CH ₂（R： -Al（CH ₂ CH（CH ₃）₂）₂）由配体的N = CH键形成的键，说明没有催化活性。使用B3LYP和基集组合（6-31 + G和cc-pVTZ）对催化剂前体和活化物种进行密度泛函理论计算，显示出对前沿轨道的了解，将LUMO定位在亚氨基键上，阐明了它们的反应性。还报道了Mulliken电荷，并且观察到配体上的氮与分子量之间的出乎意料的关系。