High molecular weight polyethylenes of narrow dispersity promoted using bis(arylimino)cyclohepta[b]pyridine-cobalt catalysts ortho-substituted with benzhydryl & cycloalkyl groups

High molecular weight polyethylenes of narrow dispersity promoted using bis(arylimino)cyclohepta[b]pyridine-cobalt catalysts ortho-substituted with benzhydryl & cycloalkyl groups Full article

Journal

Dalton Transactions
ISSN: 1477-9226 , E-ISSN: 1477-9234

Output data

Year: 2020, Volume: 49, Number: 15, Pages: 4774-4784 Pages count : 11 DOI: 10.1039/d0dt00576b

Authors

Han Mingyang ^1,2,3 , Zhang Qiuyue ^1,2,3 , Oleynik Ivan I. ⁴ , Suo Hongyi ^1,2,3 , Solan Gregory A. ^1,2,5 , Oleynik Irina V. ⁴ , Ma Yanping ^1,2 , Liang Tongling ^1,2 , Sun Wen-Hua ^1,2,3,6

Affiliations

1	(Данные Web of science) Chinese Acad Sci, Inst Chem, Key Lab Engn Plast, Beijing 100190, Peoples R China
2	(Данные Web of science) Chinese Acad Sci, Inst Chem, Beijing Natl Lab Mol Sci, Beijing 100190, Peoples R China
3	(Данные Web of science) Univ Chinese Acad Sci, CAS Res Educ Ctr, Mol Sci & Int Sch, Beijing 100049, Peoples R China
4	(Данные Web of science) NN Vorozhtsov Novosibirsk Inst Organ Chem, Pr Lavrentjeva 9, Novosibirsk 630090, Russia
5	(Данные Web of science) Univ Leicester, Dept Chem, Univ Rd, Leicester LE1 7RH, Leics, England
6	(Данные Web of science) Chinese Acad Sci, Lanzhou Inst Chem Phys, State Key Lab Oxo Synth & Select Oxidat, Lanzhou 730000, Peoples R China

A one-pot template strategy has been utilized to synthesize sterically enhanced bis(imino)cyclohepta[b]pyridine-cobalt(ii) chlorides, [2-{(Ar)N?CMe}-9-{N(Ar)}C10H10N]CoCl2 (Ar = 2-(C5H9)-4,6-(CHPh2)(2)C(6)H(2)Co1, 2-(C6H11)-4,6-(CHPh2)(2)C(6)H(2)Co2, 2-(C8H15)-4,6-(CHPh2)(2)C(6)H(2)Co3, 2-(C12H23)-4,6-(CHPh2)(2)C(6)H(2)Co4, 2,6-(C5H9)(2)-4-(CHPh2)C(6)H(2)Co5). All five complexes have been characterized by a combination of FT-IR spectroscopy, elemental analysis and single crystal X-ray diffraction. The molecular structures of Co1, Co3 and Co5 highlight the substantial steric hindrance imparted by the 2-cycloalkyl-6-benzhydryl or 2,6-dicyclopentyl ortho-substitution pattern; distorted square pyramidal geometries are exhibited in each case. On activation with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the complexes (apart from Co4/MAO) were active ethylene polymerization catalysts (up to 3.70 x 10(6) g PE per mol (Co) per h for Co5/MMAO), operating effectively at temperatures between 50 degrees C and 60 degrees C, producing polyethylenes with high molecular weights (up to 589.5 kg mol(-1) for Co3/MAO). Furthermore, all polymers were highly linear (T-m > 130 degrees C) with narrow dispersities (M-w/M-n range: 2.0-3.0). The coexistence of two chain termination pathways, beta-H elimination and transfer to aluminum, has been demonstrated using C-13/H-1 NMR spectroscopy.

Han M. , Zhang Q. , Oleynik I.I. , Suo H. , Solan G.A. , Oleynik I.V. , Ma Y. , Liang T. , Sun W-H.
High molecular weight polyethylenes of narrow dispersity promoted using bis(arylimino)cyclohepta[b]pyridine-cobalt catalysts ortho-substituted with benzhydryl & cycloalkyl groups
Dalton Transactions. 2020. V.49. N15. P.4774-4784. DOI: 10.1039/d0dt00576b WOS Scopus РИНЦ

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