A bidentate ligand 1-[2-(N,N-dimethylaminophenyl)]-3, 4-biphenylcyclopentadiene 1, as well as its corresponding constrained geometry chromium complex dichloro-η5-[1-(2-N,N-dimethylaminophenyl)-3,4-diphenylcyclopentadienyl] chromium (III) 2 have been synthesised and characterised. When activated with Al(iBu)3 and Ph3C[B(C6F5)4], complex 2 exhibits reasonable catalytic activity for ethylene polymerisation, producing polyethylenes with moderate molecular weights and melting points. The effects of polymerisation temperature, ethylene pressure, B/Cr and Al/Cr ratios on catalytic activity were studied.
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