| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1323109 | Journal of Organometallic Chemistry | 2016 | 6 Pages |
•New ansa-Fluorenylamidotitanium complexes with various substituents were synthesized.•The complexes promoted syn-specific of aspecific propylene polymerization.•The origin of the stereodefect in this polymerization system was revealed.
ansa-Fluorenylamidotitanium complexes bearing various substituents on the nitrogen and fluorene (2a-d) were synthesized. The structures of the complexes were characterized by 1H and 13C NMR, and X-ray crystal analyses were performed for complexes 2a, 2b and 2d. The coordination mode of the fluorenyl group to the metal center was changed from η3 to η1 when a bulky group was introduced on the nitrogen or 2,3-position of the fluorenyl ring. Syndiotactic-specificity of the catalyst for the propylene polymerization was reduced when bulky group was introduced on the nitrogen. Least-square fitting analysis of the steric pentad distributions revealed that the stereodefect was mainly formed by the chain migration without monomer insertion, which is accelerated by the η1-coordination of the fluorenyl group.
Graphical abstractansaFluorenylamidotitanium complexes bearing various substituents on the nitrogen and fluorene were synthesized to reveal the relationship between the structure and stereospecificity of propylene polymerization. Syndiotactic-specificity of the catalyst for the propylene polymerization was reduced when bulky group was introduced on the nitrogen.Figure optionsDownload full-size imageDownload as PowerPoint slide
