Synthesis, structural investigations and ethylene polymerization of titanium complexes with tripodal oxazoline ligands
作者:Muhammad Hafeez、Sonja Lippert、Tobias Bauer、Winfried P. Kretschmer
DOI:10.1007/s13738-014-0558-8
日期:2015.6
A series of tripodal nitrogen containing ligands including amidine and aminopyridines with extra oxazoline functionality were synthesized. The corresponding titanium complexes bearing such ligands were synthesized by diethylamine elimination route. Diethylamidotitanium trichloride [Et2NTiCl3] reacts with the functionalized anilines, 2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)-N-(2-fluorophenyl)-aniline (FOxH) and 2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)-N-(2-methoxyphenyl)aniline (MeOOxH), the amidine(E)-N’-(2,6-diisopropylphenyl)-N-(2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)phenyl)benzimidamide ( Am OxH), and the aminopyridines N-(2-(4,4-dimethyl-4,5-dihydro oxazol-2-yl)phenyl)-6-(piperidin-1-yl)pyridin-2-amine (ApOxH) and N-(2-(4,4- dimethyl- 4,5-dihydrooxazol-2-yl)phenyl)-6-(2,4,6-triisopropyl phenyl)pyridin-2-amine (Ap*OxH), under diethylamine elimination to form the corresponding titanium trichlorides [FOxTiCl3], [MeOOxTiCl3], [AmOxTiCl3], [ApOxTiCl3] and [Ap*OxTiCl3] in excellent yields. These compounds were characterized by spectroscopic methods, and X-ray crystal structure analysis (selected complexes). Furthermore, their behavior in ethylene polymerization was explored. The complexes show moderate activity towards ethylene if activated with MAO. The observed PEs were analyzed by HT-GPC and were found to be of low molecular weight for the amidinate AmOxTiCl3 but of very high one (Mp up to 3.5 million g/mol) for the aminopyridinate Ap*OxTiCl3 titanium complex.
合成了一系列包含氮的三足配体,包括具有额外氧杂环功能的氨基脲和氨基吡啶。通过二乙胺消除法合成了承载这些配体的相应钛络合物。二乙基氨基钛三氯化物 [Et2NTiCl3] 与功能化的苯胺反应,包括 2-(4,4-二甲基-4,5-氢氧杂烷-2-基)-N-(2-氟苯基)-苯胺(FOxH)和 2-(4,4-二甲基-4,5-氢氧杂烷-2-基)-N-(2-甲氧苯基)苯胺(MeOOxH)、氨基脲 (E)-N’-(2,6-二异丙基苯基)-N-(2-(4,4-二甲基-4,5-氢氧杂烷-2-基)苯基)苯并咪唑脲(Am OxH),以及氨基吡啶 N-(2-(4,4-二甲基-4,5-氢氧杂烷-2-基)苯基)-6-(哌啶-1-基)吡啶-2-胺(ApOxH)和 N-(2-(4,4-二甲基-4,5-氢氧杂烷-2-基)苯基)-6-(2,4,6-三异丙基苯基)吡啶-2-胺(Ap*OxH),在二乙胺消除的条件下,形成了相应的钛三氯化物 [FOxTiCl3]、[MeOOxTiCl3]、[AmOxTiCl3]、[ApOxTiCl3] 和 [Ap*OxTiCl3],且产率甚高。通过光谱方法以及 X 射线晶体结构分析(选定络合物)对这些化合物进行了表征。此外,还探讨了它们在乙烯聚合中的行为。如果用 MAO 激活,这些配合物对乙烯显示出中等活性。观察到的聚合物通过 HT-GPC 分析,氨基脲 AmOxTiCl3 的分子量较低,而氨基吡啶钛络合物 Ap*OxTiCl3 的分子量则非常高(Mp 高达 350 万 g/mol)。