Iron(II) complexes ligated by 2-imino-1,10-phenanthrolines: Preparation and catalytic behavior toward ethylene oligomerization

• Published in: Journal of molecular catalysis. A, Chemical Vol. 269; no. 1; pp. 85 - 96
• Main Authors: Jie, Suyun, Zhang, Shu, Sun, Wen-Hua, Kuang, Xiaofei, Liu, Tianfu, Guo, Jianping
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 18.05.2007; Elsevier
• Subjects: 2-Imino-1,10-phenanthroline; Catalysis; Chemistry; Ethylene reactivity; Exact sciences and technology; General and physical chemistry; Iron complex; Polyethylene wax; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; α-Olefins; Iron complex; Polyethylene wax; α-Olefins; Ethylene reactivity; 2-Imino-1,10-phenanthroline; Iron II Complexes; Polyethylene; Catalytic reaction; Oligomerization; Organic ligand; Wax; Olefin; Preparation; Chemical reactivity; Ethylenic compound
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2007.01.008

A series of N, N, N-tridentate iron (II) complexes bearing 2-imino-1,10-phenanthrolines, [2-{(2,6-R 1,R 3-4-R 2-C 6H 2)N C(R)}-1,10-phen]FeCl 2, was synthesized and characterized by IR spectroscopy and elemental analysis. One of these complexes ( 18b) was determined by single-crystal X-ray crystallography for its unambiguous structure. These iron(II) complexes were found to exhibit remarkable activities for ethylene oligomerization in the presence of MAO or MMAO cocatalyst affording α-olefins with high selectivity and the composition of oligomers followed the Schluz–Flory distribution. The effects of substituents on imino fragment on the activity were explored in detail; complexes with mono substituent at the ortho-position of the phenyl ring showed high activities with low K values, suggesting that fine tuning of the steric bulk of substituents on the imino fragment directly affects both the activity and the selectivity. A series of N, N, N-tridentate iron (II) complexes bearing 2-imino-1,10-phenanthrolines was synthesized and characterized. Activated with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), those iron complexes were found to be highly active catalysts for ethylene reactivity with high selectivity for α-olefins. The influences of the reaction parameters were examined for the inherent regularity of catalytic behavior. ▪