Iminopyridine-Based Cobalt(II) and Nickel(II) Complexes: Synthesis, Characterization, and Their Catalytic Behaviors for 1,3-Butadiene Polymerization

Polymers

Quanquan Dai¹  Xiangyu Jia¹  Feng Yang²  Chenxi Bai¹  Yanming Hu¹  Xuequan Zhang² 

[1] Key Laboratory of Synthetic Rubber, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China

关键词: iminopyridine;    cobalt;    nickel;    1;    3-butadiene;    polybutadiene;   

DOI  :  10.3390/polym8010012

来源: mdpi

【 摘 要 】

A series of iminopyridine ligated Co(II) (1a–7a) and Ni(II) (1b–7b) complexes were synthesized. The structures of complexes 3a, 4a, 5a, 7a, 5b, and 6b were determined by X-ray crystallographic analyses. Complex 3a formed a chloro-bridged dimer, whereas 4a, 5a, and 7a, having a substituent (4a, 5a: CH₃; 7a: Br) at the 6-position of pyridine, producing the solid structures with a single ligand coordinated to the central metal. The nickel atom in complex 5b features distorted trigonal-bipyramidal geometry with one THF molecule ligating to the metal center. All the complexes activated by ethylaluminum sesquichloride (EASC) were evaluated in 1,3-butadiene polymerization. The catalytic activity and selectivity were significantly influenced by the ligand structure and central metal. Comparing with the nickel complexes, the cobalt complexes exhibited higher catalytic activity and cis-1,4-selectivity. For both the cobalt and nickel complexes, the aldimine-based complexes showed higher catalyst activity than their ketimine counterparts.

【 授权许可】

CC BY   
© 2016 by the authors; licensee MDPI, Basel, Switzerland.