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 2-(1-aryliminoethyl)-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridylcobalt chlorides were synthesized and characterized using FT-IR and elemental analysis, and the molecular structures of complexes , and were confirmed to present a pseudo-square-pyramidal or trigonal-bipyramidal geometry around the cobalt center using single-crystal X-ray diffraction. Upon activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all cobalt precatalysts gave high activities up to the level of 10(7) gPE mol(-1) (Co) h(-1) toward ethylene polymerization, being one of most active cobalt-based precatalysts. In comparison with cobalt analogues, the title precatalysts generally possessed longer lifetime along with good thermo-stability; moreover, the resultant polyethylenes were highly linear and unimodal in most cases.

Highly active para-t-Bu-containing 1,2-bis(imino)acenaphthene-Ni(ii) catalysts are disclosed which afford hyper-branched PEs with Mw's up to 3.1 × 106 g mol−1; high tensile strength, excellent shape fixity as well as high elongation at break are a feature.

The ruthenium complex (8-(2-diphenylphosphinoethyl)­aminotrihydroquinolinyl)­(carbonyl)­(hydrido)­ruthenium chloride exhibited extremely high efficiency toward the coupling cyclization of γ-amino alcohols with secondary alcohols. The corresponding products, pyridine or quinoline derivatives, are obtained in good to high isolated yields. On comparison with literature catalysts whose noble-metal loading with respect to γ-amino alcohols reached 0.5–1.0 mol % for Ru and a record lowest of 0.04 mol % for Ir, the current catalyst achieves the same efficiency with a loading of 0.025 mol % for Ru. The mechanism of acceptorless dehydrogenative condensation (ADC) was proposed on the basis of DFT calculations; in addition, the reactive intermediates were determined by GC-MS, NMR, and single-crystal X-ray diffraction. The catalytic process is potentially suitable for industrial applications.

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

Cycloalkyl-modified 8-arylimino-5,6,7-trihydroquinolylnickel pre-catalysts highly polymerize ethylene into branched polyethylene waxes.

A series of 9-(2-cycloalkylphenylimino)-5,6,7,8-tetrahydrocycloheptapyridine derivatives (L1-L3) was synthesized, and reacted with nickel halides to form their corresponding nickel complexes (bromide: Ni1-Ni3; chloride: Ni4-Ni6). All organic compounds and nickel complexes were well characterized. The structure of a representative complex Ni1 was determined by a single crystal X-ray study, revealing a distorted trigonal bipyramidal geometry at the nickel centre. Upon activation with either modified methylaluminoxane (MMAO) or diethylaluminium chloride (Et 2 AlCl), all nickel complexes showed high activities toward ethylene polymerization. The obtained polymers were confirmed to be polyethylene waxes with low molecular weights (in the range of 1.83 to 6.78 kg mol À1 ) and narrow polydispersity (PDI:1.38-1.78); moreover, the obtained polyethylenes were highly branched ones. These polyethylene waxes have potential application as functional adducts of lubricants or pour-point depressants.

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