A series of α,α′-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridyliron chlorides exhibits high activities toward ethylene polymerization, yielding highly linear vinyl-polyethylenes.

A series of α,α′-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridylcobalt chlorides was synthesized by the one-pot template reaction of α,α′-dioxo-2,3:5,6-bis(pentamethylene)pyridine, anilines, and cobalt chloride in refluxing acetic acid. The molecular structure of complex Co1 was determined by singlecrystal X-ray crystallography, which revealed a distorted squarepyramidal geometry around the cobalt center. On activation with methylaluminoxane or modified methylaluminoxane, all of [a]

A series of 1-(2,6-dibenzhydryl-4-fluorophenylimino)-2-aryliminoacenaphthylene derivatives (L1-L5) and their halonickel complexes LNiX 2 (X 5 Br, Ni1-Ni5; X 5 Cl, Ni6-Ni10) are synthesized and well characterized. The molecular structures of representative complexes Ni2 and Ni4 are confirmed as the distorted tetrahedron geometry around nickel atom by the single crystal X-ray diffraction. Upon activation with methylaluminoxane, all nickel complexes show high activities up to 1.49 3 10 7 g of PE

The stoichiometric reactions of 5,6,7,8-tetrahydrocycloheptapyridin-9-one (cycloheptapyridin-9-one) with various anilines lead to corresponding mixtures of 9-aryliminocycloheptapyridine and the isomeric 9-arylamino-5,6,7-trihydrocycloheptapyridine derivatives; these compounds further reacted with nickel dichloride to form 9-aryliminocycloheptapyridyl nickel chlorides, respectively. The new organic compounds were analyzed by the NMR measurements, and all the organic and complex compounds were characterized by the FT-IR spectroscopy and elemental analysis. In addition, the molecular structures of representative nickel complexes and , determined by means of single-crystal X-ray diffraction, were found to be binuclear dimers with distorted square-pyramidal geometry around the nickel centers. On activation with either ethylaluminium sesquichloride (Et3Al2Cl3) or methylaluminoxane (MAO), all nickel complex pre-catalysts exhibited high activities of up to 7.80 × 10(6) g PE mol(-1) (Ni) h(-1) toward ethylene polymerization and produced highly branched polyethylenes in narrow polydispersity. The title nickel complexes showed comparable activities with 8-arylimino-5,6,7-trihydroquinolyl nickel analogues; whilst both exhibited higher activities than did the 2-iminopyridyl nickel analogues due to the enhancement of the ring-tension of cyclic-fused pyridine derivatives.

The 2-(1-(arylimino)ethyl)-7-arylimino-6,6-dimethylcyclopentapyridylcobalt complexes were constrainedly prepared, performing polymerization with MAO but oligomerization with MMAO.

Five examples of α,α'-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridyl-chromium(iii) chlorides (aryl = 2,6-MePh Cr1, 2,6-EtPh Cr2, 2,6-i-PrPh Cr3, 2,4,6-MePh Cr4, 2,6-Et-4-MePh Cr5) have been synthesized by the one-pot template reaction of α,α'-dioxo-2,3:5,6-bis(pentamethylene)pyridine, CrCl·6HO and the corresponding aniline. The molecular structures of Cr1 and Cr4 reveal distorted octahedral geometries with the N,N,N-ligand adopting a mer-configuration. On activation with an aluminium alkyl co-catalyst, Cr1-Cr5 exhibited high catalytic activities in ethylene polymerization and showed outstanding thermal stability operating effectively at 80 °C with activities up to 1.49 × 10 g of PE (mol of Cr) h. Significantly, the nature of the co-catalyst employed had a dramatic effect on the molecular weight of the polymeric material obtained. For example, using diethylaluminium chloride (EtAlCl) in combination with Cr4 gave high density/high molecular weight polyethylene with broad molecular weight distributions (30.9-39.3). By contrast, using modified methylaluminoxane (MMAO), strictly linear polyethylene waxes of lower molecular weight and narrow molecular weight distribution (1.6-2.0) were obtained with vinyl end-groups.

A series of 2‐(1‐(2,4‐bis((di(4‐fluorophenyl)methyl)‐6‐methylphenylimino)ethyl)‐6‐(1‐(aryl­imino)ethyl)pyridines is synthesized and used to form their corresponding iron(II) and cobalt(II) chloride complexes thereof. All the organic compounds are fully characterized by elemental analysis, and IR and 1H/13C NMR spectroscopy, whereas the corresponding iron and cobalt complexes are characterized by elemental analysis and IR spectroscopy, as well as single‐crystal crystallography for the Fe2, Co1, and Co2 complexes, revealing a distorted trigonal bipyramidal structure. Upon activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the iron complexes exhibit high activities toward ethylene polymerization at 60 °C; meanwhile, all the cobalt analogs demonstrate slightly lower activities at the optimized temperatures of 60 °C (MAO as cocatalyst) or 70 °C (MMAO as cocatalyst). All the polyethylenes obtained from cobalt precatalysts possess narrow polydispersity and lower molecular weights than those from their iron analogs.

Supplementary Information (ESI) available: NMR spectra for the ligands L1 -L5 and complexes Ni1 -Ni10; crystallographic data in CIF format. CCDC 1504611 (Ni2) 1504612 (Ni4). See