Highly 2,3-Selective Polymerization of Phenylallene and Its Derivatives with Rare-Earth Metal Catalysts: From Amorphous to Crystalline Products
作者:Fei Lin; Zhaohe Liu;Tiantian Wang;and Dongmei Cui
关键字:Highly 2,3-Selective,Phenylallene,Crystalline Products

Rare-earth metal complexes (Flu-CH2-Py)Ln-(CH2SiMe3)2(THF)n (Ln=Sc(1), Lu(2), Tm(3), Y(4) andGd(5)), upon the activation of [Ph3C][B(C6F5)4] and AliBu3,were employed to catalyze the polymerization of allene derivatives under mild conditions. The Gd, Y, Tm, Lu metal based precursors exhibited distinguished 2,3-selectivity(>99.9%) for phenylallene (PA) polymerization, whereas the smallest Sc metal based precursor showed a moderate 2,3-selectivity. The activity increased with the central metal size following the trend of Gd(5)>Tm(4)>Y(3)>Lu(2)>Sc(1).Moreover, Gd(5) also realized the purely 2,3-selective polymerizations of polar or nonpolar allene derivatives, paramethylphenylallene, para-flourophenylallene and paramethoxyphenylallene,regardless of electron-donating or -withdrawing substituents. Owing to the highly regular backbones,these polymers (except PPA) were crystalline, thus being the first crystalline polymers based on allene derivatives