Syndio-specific polymerization of styrene promoted by rare-earth metal bis(aminobenzyl) complexes bearing pyrrolyl-modified arylamide ligands

Publication date: Available online 15 August 2018Source: Journal of Organometallic ChemistryAuthor(s): Chaopan Wang, Min Li, Zehuai Mou, Yunjie LuoAbstractAcid-base reaction of the rare-earth metal tris(o-dimethylaminobenzyl) complexes Ln (CH2C6H4NMe2-o)3 with 1 equiv. of the pyrrolyl-modified arylamide ligands 2,5-Me2C4H2NSiMe2NHC6H4R (R = H, Cl-p, OMe-p) in toluene gave (2,5-Me2C4H2NSiMe2NC6H5)Ln (CH2C6H4NMe2-o)2 (Ln = Sc (1), Y (2), Lu (3)), (2,5-Me2C4H2NSiMe2NC6H4Cl-p)Y(CH2C6H4NMe2-o)2 (4), and (2,5-Me2C4H2NSiMe2NC6H4OMe-p)Y(CH2C6H4NMe2-o)2 (5) in good isolated yields. These complexes were well-characterized by elemental analysis and NMR spectroscopy. 1, 2 and 4 were structurally determined by single crystal X-ray diffraction. The catalyst systems of 1–5/AliBu3/[Ph3C][B(C6F5)4] were able to promote styrene polymerization to afford pure and highly syndio-tactic polystyrene (rrrr > 99%). Among these rare-earth metal complexes, the complexes with the central metal being the cheapest yttrium showed much higher activity than the expensive scandium analogues. The styrene polymerization catalyzed by 4/AliBu3/[Ph3C][B(C6F5)4] proceeded in a controlled fashion.Graphical abstract

Source: Journal of Organometallic Chemistry - August 15, 2018 Category: Chemistry Source Type: research