1448643-65-9Relevant academic research and scientific papers
Neutral dimethylzirconocene complexes as initiators for the ring-opening polymerization of ε-caprolactone
Villasenor, Elena,Gutierrez-Gonzalez, Ruben,Carrillo-Hermosilla, Fernando,Fernandez-Galan, Rafael,Lopez-Solera, Isabel,Fernandez-Pacheco, Ana Rodriguez,Antinolo, Antonio
, p. 1184 - 1196 (2013/04/10)
The synthesis, structures, and ring-opening polymerization (ROP) activity of new dimethyl-ansa- and -non-ansa-zirconocene complexes are reported. The substituted indene precursors 1-C9H7R [R = CH3 (1), CH2Ph (2) and C2H4(C4H 7O2) (3)] were synthesised by treating RBr [R = CH 2Ph and C2H4(C4H7O 2)] or MeI with indenyllithium. Likewise, bridged indenyl/cyclopentadiene compounds [Me2Si(3-C9H 6R)(C5Me4H)] [R = H (4), CH3 (5), CH2Ph (6) and C2H4(C4H 7O2) (7)] were obtained by treating the lithium salt of the appropriately substituted indene with ClSiMe2(C 5Me4H). ansa-Indenyl-cyclopentadienylmetallocenes [Zr{Me2Si(3-η5-C9H5R) (η5-C5Me4)}Cl2] [R = H (8), CH3 (9), CH2Ph (10), C2H4(C 4H7O2) (11)] were subsequently obtained by treating the dilithium salts of the corresponding ligands with ZrCl4 in toluene. The dimethyl derivatives [Zr{Me2Si(3-η5- C9H5R)(η5-C5Me 4)}Me2] [R = H (12), CH3 (13), CH2Ph (14), C2H4(C4H7O2) (15)] were prepared by treating the corresponding ansa-zirconocene dichloride complex with MgMeBr. Dialkyl derivative [Zr{Me2Si{3-η5-C 9H5(CH2Ph)}(η5-C 5Me4)}(CH2SiMe3)2] (16) was prepared by adding 2 equiv. of LiCH2SiMe3 to complex 10. Mixed indenyl/cyclopentadienylzirconocene complexes [Zr(η5- C9H6R)(η5-C5H 5)Cl2] [R = H (17), C2H4(C 4H7O2) (18)] were prepared by treating the lithium salt of the appropriately substituted indene with [Zr(η5- C5H5)Cl3]. Likewise, dimethyl derivatives [Zr(η5-C9H6R)(η5-C 5H5)Me2] [R = H (19), C2H 4(C4H7O2) (20)] were prepared by treating the corresponding mixed indenyl/cyclopentadienyl dichloride complex with 2 equiv. of MgMeBr. The X-ray crystal structures of 7, 12, and 13 were also established. Finally, comparative catalytic studies of zirconium complexes 12-16, 19 and 20 in ROP reactions of ε-caprolactone are described. Synthesis, characterization, and catalytic studies of new dimethyl-ansa- and -non-ansa-zirconocene complexes for ring-opening polymerization of ε-caprolactone are described. Copyright
