Enantio‐ and Stereoselective Cyclopolymerization of Hexa‐1, 5‐diene Catalyzed by Zirconium Complexes Possessing Optically Active Bis(phenolato) Ligands. Issue 22 (26th September 2016)

• Record Type: Journal Article
• Authors: Nakata, Norio; Watanabe, Takanori; Toda, Tomoyuki; Ishii, Akihiko
• Is Part Of: Macromolecular rapid communications. Volume 37:Issue 22(2016)
• Page Start: 1820
• Page End: 1824
• Publication Date: 2016-09-26
• Subjects: cyclopolymerization -- hexa‐1, 5‐diene -- isoselective -- optically active polymers -- zirconium; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201600351
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract : Enantio‐ and stereoselective cyclopolymerization of hexa‐1, 5‐diene was achieved by enantiomerically pure dichloro zirconium(IV) pre‐catalysts2 possessing chiral [OSSO]‐type bis(phenolate) ligands (−)‐1 and (+)‐1 in combination with dried methylaluminoxane (dMAO) as an activator. The corresponding activities were recorded with quite high values up to 1, 960 g mmol(2 ) –1 h –1, which are extremely larger than those of the related complexes. The microstructure analysis for the PMCPs furnished by pre‐catalysts (Λ, S, S )‐2 and (Δ, R, R )‐2 showed good isotacticity factors (α = 75−78%) and relatively high proportions of trans ‐cyclopentane rings (σ = 14−21%). These enantiomeric PMCPs exhibited large specific optical rotations ([α]D = +28 to +32° from (Λ, S, S )‐2, −26 to −34° from (Δ, R, R )‐2 ). Abstract : Cyclopolymerization of hexa‐1, 5‐diene with enantiomerically pure dichloro zirconium(IV) pre‐catalysts possessing chiral [OSSO]‐type bis(phenolate) ligands (−)‐1 and (+)‐1 in combination with dried methylaluminoxane (dMAO) as an activator led to the formations of isoselective (α = 75−78%) and trans ‐preferential (σ = 14−21%) PMCPs, accompanying the quite high activities recorded in the range of 147−1, 960 g mmol(2 ) –1 h –1 . Notably, the trans ‐enriched isotactic PMCPs produced exhibited relatively large specific optical rotations.