کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1325108 977369 2011 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Vinyl addition polymerization of norbornene catalyzed by β-iminoamine Ni(II) complexes/methylaluminoxane systems
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Vinyl addition polymerization of norbornene catalyzed by β-iminoamine Ni(II) complexes/methylaluminoxane systems
چکیده انگلیسی

Two nickel(II) complexes (A and B) bearing β-iminoamine ligands, [2-(ArNCH)-C6H4-NMe2] (La, Ar = 2,6-i-Pr2C6H3; Lb, Ar = 2,6-Me2C6H3), were synthesized and characterized by elemental analyses and 1H NMR. X-ray crystal structure of complex B reveals that the six-membered chelate ring adopts a envelope conformation, with nickel(II) atom deviating from the plane of backbone aromatic ring by 1.164 Å. In the presence of methylaluminoxane (MAO), both complexes showed moderate activities of 105 g molNi−1 h−1 for norbornene polymerization. β-iminoamine Ni(II)/MAO catalysts gave unimodal polymers (Mw, 3.16–8.02 × 105 g/mol) with a relatively narrow MWD (Mw/Mn, 1.59–2.14), indicative of single-site catalyst behavior. The obtained polymers are vinyl-type polynorbornenes (PNBs), which are soluble in common solvents such as toluene, cyclohexane and dichlorobenzene.

β-iminoamine ligands and Ni(II) complexes were synthesized and characterized. In the presence of MAO, β-iminoamine Ni(II) complexes were used as catalyst precursors for norbornene polymerization. β-iminoamine Ni(II)/MAO catalysts produce soluble vinylic polynorbornenes at an activity level of 105 g mol−1 h−1. The influences of temperature, Al/Ni ratios and precursor structure on polymerization behavior were examined.Figure optionsDownload as PowerPoint slideHighlights
► Cationic Ni(II) complexes with six-membered chelate ring as catalyst precursors.
► Catalysts for vinyl addition polymerization of norbornene.
► Ni(II)/MAO produce vinylic polynorbornenes at 105 g mol−1 h−1 level.
► Unimodal and narrow MWD (1.59–2.14), indicative of single-site catalyst behavior.
► Sterically open precursors with nonplanar conformation are less active catalysts.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Organometallic Chemistry - Volume 696, Issue 23, 15 November 2011, Pages 3697–3702
نویسندگان
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