| 초록 |
The elastomeric polybutadienes (PBDs) of high cis-1,4 stereo isomer is one of the most important raw material in tire industry. Single-site homogeneous catalysts are recently employed in the production of cis-1,4 PBDs, where the choice of ligand architecture and metal is decisive. Herein, we are reporting the synthesis of a new series of cobalt(II) complexes bearing tridentate bis(benzimidazolyl)pyridyl amine ligands of varying electronic nature and its features towards the polymerization of 1,3 butadiene (BD). The complexes were highly effective for BD polymerizations, on activation with ethylaluminum sesquichloride (EASC), in a stereoselective fashion predominated by cis-1,4 isomer (up to 97%). The polymers were characterized by high molecular weight with distribution ranging from 1.5 to 3.9. The substituents had significant effect on activity, keeping the stereochemistry in similar levels, but different reaction conditions remarkably affected the microstructure of PBDs. |
