US EPA

4726579 

Journal Article 

Synthesis, characterization and 1,3-butadiene polymerization behaviors of three ONO, ONN, and NNN tridentate Co(II) complexes 

Liu, H; Wang, F; Liu, Li; Dong, Bo; Zhang, H; Bai, Cxi; Hu, Y; Zhang, X 

2014 

1 

Inorganica Chimica Acta
ISSN: 0020-1693
EISSN: 1873-3255 

421 

284-291 

10.1016/j.ica.2014.06.010 

WOS:000341439300033 

http://www.sciencedirect.com/science/article/pii/S0020169314003636
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Three kinds of ONO (a), ONN(b), and NNN (c) tridentate Co(II) complexes were synthesized and thoroughly characterized. Determined by single crystal X-ray analysis, the solid structures of b and c displayed distorted trigonal bipyramidal and square pyramidal geometries around the metal centre, respectively. In combination with methylaluminoxane (MAO), all three complexes exhibited high catalytic activities towards 1,3-butadiene polymerization, affording polymers with predominant cis-1,4-contents. With addition of PPh3 into the polymerization system, polybutadienes having predominant 1,2-contents were obtained, while the addition of PO(OPh)(3) showed little influence on the microstructure of the polymer. In the investigation of chain transfer polymerization of 1,3-butadiene at the presence of ZnEt2, for complexes a and b, monotonous decreasing in molecular weight along with and an increasing of cis-1,4-content were obtained with an increasing molar ratio of Zn/Co, for complex c, however, unconspicuous changes was observed. (C) 2014 Elsevier B.V. All rights reserved. 

Cobalt(II) complexes; 1,3-Butadiene polymerization; Phosphorus compounds; Chain transfer; Diethyl zinc