Synthesis, structural characterization, and reactivity of organolanthanides derived from a new chiral ligand (S)-2-(pyrrol-2-ylmethyleneamino)-2′-hydroxy-1,1′-binaphthyl
作者:Qiuwen Wang、Li Xiang、Guofu Zi
DOI:10.1016/j.jorganchem.2007.10.022
日期:2008.1
Condensation of (S)-2-amino-2'-hydroxy-1,1'-binaphthyl with 1 equiv. of pyrrole-2-carboxaldehyde in toluene in the presence of molecular sieves at 70 degrees C gives (S)-2-(pyrrol-2-ylmethyleneamino)-2'-hydroxy-1,1'-binaplithyl (1H(2)) in 90% yield. Deprotonation of 1H(2) with NaH in THF, followed by reaction with LnCl(3) in THF gives, after recrystallization from a toluene or benzene solution, dinuclear complexes (1)(3)Y-2,(thf)(2)-3C(7)H(8) (3 center dot 3C(7)H(8)) and (1)(3)Yb-2(thf)(2) center dot 3C(6)H(6) (4 - 3C(6)H(6)), respectively, in good yields. Treatment of 1H(2) with Ln[N(SiMe3)(2)](3) in toluene under reflux, followed by recrystallization from a benzene solution gives the dimeric amido complexes (1-LnN(SiMe3)(2))(2) center dot 2C(6)H(6) (Ln = Y (5 center dot 2C(6)H(6)), Yb (6 center dot 2C(6)H(6))) in good yields. All compounds have been characterized by various spectroscopic techniques, elemental analyses and X-ray diffraction analyses. Complexes 5 and 6 are active catalysts for the polymerization of methyl methacrylate (MMA) in toluene, affording syn-rich poly-(MMA)s. (c) 2007 Elsevier B.V. All rights reserved.