Probing the effect of ortho-cycloalkyl ring size on activity and thermostability in cycloheptyl-fused N,N,N-iron ethylene polymerization catalysts

Probing the effect of ortho-cycloalkyl ring size on activity and thermostability in cycloheptyl-fused N,N,N-iron ethylene polymerization catalysts Научная публикация

Журнал

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

Вых. Данные

Год: 2020, Том: 49, Номер: 1, Страницы: 136-146 Страниц : 11 DOI: 10.1039/c9dt04325j

Авторы

Guo Jingjing ^1,2,3 , Zhang Wenjuan ¹ , Oleynik Ivan I. ⁴ , Solan Gregory A. ^1,5 , Oleynik Irina, V ⁴ , Liang Tongling ^2,3 , Sun Wen-Hua ^2,3

Организации

1	(Данные Web of science) Beijing Inst Fash Technol, Sch Mat Sci & Engn, Beijing Engn Res Ctr Text Nanofiber, Beijing Key Lab Clothing Mat R&D & Assessment, Beijing 100029, Peoples R China
2	(Данные Web of science) Chinese Acad Sci, Inst Chem, Key Lab Engn Plast, Beijing 100190, Peoples R China
3	(Данные Web of science) Chinese Acad Sci, Inst Chem, Beijing Natl Lab Mol Sci, Beijing 100190, 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

The syntheses of six bis(imino)-5,6,7,8-tetrahydrocycloheptapyridine-iron(ii) chloride complexes, [2-{(Ar)NCMe}-9-{N(Ar)}C10H10N]FeCl2 (Ar = 2-(C5H9)-6-MeC(6)H(3)Fe1, 2-(C6H11)-6-MeC(6)H(3)Fe2, 2-(C8H15)-6-MeC(6)H(3)Fe3, 2-(C5H9)-4,6-Me(2)C(6)H(2)Fe4, 2-(C6H11)-4,6-Me(2)C(6)H(2)Fe5, 2-(C8H15)-4,6-Me(2)C(6)H(3)Fe6), are reported in which the ring size of the ortho-cycloalkyl group has been varied as has the type of para-substituent. The molecular structures of Fe3 and Fe6 reveal square pyramidal geometries at iron while the ortho-cyclooctyl rings adopt boat-chair conformations. On treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all six complexes showed optimal activities at 80 degrees C [up to 1.9 x 10(7) g of PE per mol Fe per h for Fe5/MMAO] for ethylene polymerization forming linear polyethylene (T-m's > 126 degrees C). Notably, the catalytic activities showed a marked correlation with the ring size of the ortho-cycloalkyl substituent: cyclohexyl (Fe2 and Fe5) > cyclooctyl (Fe3 and Fe6) > cyclopentyl (Fe1 and Fe4) for either para-substituent, H or Me. Furthermore, this family of iron catalysts exhibited remarkable thermostability by remaining highly active even at temperatures as high as 100 degrees C (1.1 x 10(7) g of PE per mol Fe per h); the wide variation in polymer molecular weights (M-w: 2.4-166 kg mol(-1)), influenced through choice of precatalyst and co-catalyst as well as by temperature and pressure, further highlights the versatility of these catalysts.

Guo J. , Zhang W. , Oleynik I.I. , Solan G.A. , Oleynik I.V. , Liang T. , Sun W-H.
Probing the effect of ortho-cycloalkyl ring size on activity and thermostability in cycloheptyl-fused N,N,N-iron ethylene polymerization catalysts
Dalton Transactions. 2020. V.49. N1. P.136-146. DOI: 10.1039/c9dt04325j WOS Scopus РИНЦ

Web of science	WOS:000507637400013
Scopus	2-s2.0-85076809313
РИНЦ	43222928
OpenAlex	W2991449446