| Abstract
| - A series of iron(II) (7a−11a) and cobalt(II) (7b−11b) 2-(1-methyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl complexes were synthesized, as well as bidentate iron(II) and cobalt(II) complexes ligatedby 2-(2-benzimidazolyl)-6-methylpyridine, 2-(carboethoxyl)-6-(2-benzimidazolyl)pyridine, and 2-(1-methyl-2-benzimidazolyl)-6-acetylpyridine. All organic compounds were fully characterized by NMRand IR spectroscopy and elemental analysis, while the metal complexes were carefully examined by IRspectroscopy and elemental analysis. Their molecular structures were determined by single-crystal X-raydiffraction analysis. The bidentate metal complexes display a distorted-tetrahedral coordination geometry;however, 2a is an exception, with a distorted-trigonal-bipyramidal geometry due to coordination of oneDMF molecule. The X-ray crystallographic studies on all of the tridentate metal complexes revealed thecoordination geometry as a distorted trigonal bipyramid. Upon activation with MAO or MMAO, theiron(II) 2-(2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl complexes showed high activities with goodα-olefin selectivity, while the cobalt(II) analogues displayed moderate to good catalytic activities. However,other bidentate metal complexes showed considerable moderate catalytic activity. The oligomers andpolyethylene waxes obtained were α-olefins, and the distribution of oligomers resembled Schulz−Floryrules with some exceptions. Various reaction parameters were investigated, and the results revealed thatboth the steric and electronic effects of ligands affect the catalytic activities of their metal complexes aswell as the distribution of products.
- The title iron complexes were synthesized, and they performed as good catalysts for ethylene reactivity with high linear α-olefin selectivity, while their cobalt analogues showed moderate catalytic activity.
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