کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5184232 1381042 2010 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selective activation of metallic center in heterobinuclear cobalt and nickel complex in ethylene polymerization
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Selective activation of metallic center in heterobinuclear cobalt and nickel complex in ethylene polymerization
چکیده انگلیسی

Heterobinuclear cobalt and nickel complex {2-[2,6-R2-C6H3NC(CH3)-(CH3)CN-(3,5-R2′)C6H2-CH2-(3′,5′-R2)C6H2NC(CH3)]-6-[2,6-R2-C6H3NC(CH3)] pyridine}CoCl2NiBr2 (R = isopropyl) (N5CoNi) was prepared by reaction of pentadentate nitrogen ligand containing 2,6-bis(imino)-pyridine and α-diimine moieties with CoCl2 and NiBr2(DME) in turn. The complex was applied as catalyst for ethylene polymerization activated by AlEt3, MMAO and AlEt3/[PhMe2NH] [B(C6F5)4] respectively. The performance of the heterobinuclear complex in ethylene polymerization was compared with corresponding mononuclear complexes (α-diimine nickel bromide and 2,6-bis(imino)-pyridine cobalt chloride) and their equivalent mixture (binary complexes). When the complex N5CoNi was activated by AlEt3 or MMAO, its ethylene polymerization activity was lower than its control, the binary complexes. Both heterobinuclear complex and binary complex produced PE with bimodal molecular weight distribution. The amount of high-molecular-weight polyethylene produced by nickel center of N5CoNi was less than the binary complexes, which reveals that productivity of nickel center of N5CoNi is selectively suppressed. When the heterobinuclear complex N5CoNi is activated by AlEt3/[PhMe2NH][B(C6F5)4], the relative productivity of nickel center increased, although the total activity of catalyst decreased compared with AlEt3 as cocatalyst. With respect to AlEt3, [PhMe2NH][B(C6F5)4] can preferably activate nickel center of heterobinuclear complex. The results suggest that metal site in the heterobinuclear complex is selectively activated by cocatalyst.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 51, Issue 14, 24 June 2010, Pages 3091-3098
نویسندگان
, , ,