787616-22-2Relevant academic research and scientific papers
Preparation, structure and ethylene polymerization/oligomerization behavior of 2-carbethoxy-6-iminopyridine-based transition metal complexes
Su, Bi-Yun,Zhao, Jian-She
, p. 3289 - 3298 (2008/10/09)
The synthesis, characterization and ethylene polymerization/oligomerization of a series of transition metal complexes with the formula {2-carbethoxy-6-[1-[(2,6-dimethylphenyl)imino]-ethyl]pyridine}nMCl2 [M = Mn(II) (8), Fe(II) (9), Co(II) (10), Cu(II) (11), Zn(II) (12), n = 1; Ni(II) (13), n = 2]; {2-carbethoxy-6-[1-[(2,4,6- trimethylphenyl)imino]ethyl]pyridine}MCl2 [M = Fe(II) (14), Co(II) (15), Ni(II) (16)]; {2-carbethoxy-6-[1-[(2,6-diethylphenyl)-imino]ethyl]pyridine}MCl2 [M = Fe(II) (17), Co(II) (18), Ni(II) (19)] have been reported. Systematic studies are focused on the relationship between the catalytic activity of these complexes for ethylene polymerization/oligomerization and the electronic property of the central metal, the ligand structure, as well as the reaction conditions. The Fe(II), Co(II), Ni(II) catalyst systems afford moderate activities ranging from 0.35 × 104 to 5.9 × 104 g/mol-Metal h atm, and the most active catalysts are those with two smaller substituents in the ortho-positions of the N-aryl ring. X-ray crystallographic analysis of complex 12 reveals a four-coordinated distorted tetrahedral geometry, while complex 18 indicates a five-coordinated distorted trigonal bipyramid, in which the tridentate ligand coordinates via weak bonding between the carbonyl oxygen of the ester group and cobalt.
Synthesis, characterization, and ethylene oligomerization and polymerization of ferrous and cobaltous 2-(ethylcarboxylato)-6-iminopyridyl complexes
Sun, Wen-Hua,Tang, Xiubo,Gao, Tielong,Wu, Biao,Zhang, Wenjuan,Ma, Hongwei
, p. 5037 - 5047 (2008/10/09)
A series of ferrous complexes (L)FeCl2 (3a-f) and cobaltous complexes (L)CoCl2 (4a-f) were prepared by the reaction of 2-(carboxylato)-6-iminopyridines 2a-f (2-COOEt-6-(2,6-R2C 6H3N=CCH3)C5H3N: 2a, R = CH3; 2b, R = Et; 2c, R = i-Pr; 2d, R = F; 2e, R = Cl; 2f, R = Br) with FeCl2 or Coda. The obtained complexes were characterized by elemental analysis and IR spectroscopy, and the solid-state structures of 2b,c, 3b,c,e,f, and 4c,f were determined by X-ray diffraction analysis. X-ray crystallographic analyses of complexes 3c,e,f and 4c,f reveal a four-coordinated distorted-tetrahedral geometry, except for complex 3b, in which the tridentate ligand is coordinated through a weak bonding between iron and the carbonyl oxygen of the ester group. The complexes were studied for ethylene oligomerization and polymerization in the presence of methylaluminoxane (MAO) under various reaction conditions. It was found that the ferrous complexes exhibit higher activities for ethylene polymerization than for oligomerization, while the cobaltous complexes show higher activities for ethylene oligomerization. In addition, the ferrous catalytic systems predominantly produce linear oligomers and polyethylene with unsaturated end groups.
