placement of fluorine substituents especially in the ortho-position strongly affected the catalytic activity. The ROPs by 2a−6a were accompanied by a certain degree of side reactions (transesterification), whereas the living polymerization systems can be accomplished using the C6F5 analogues (1a−c). Therefore, the C6F5 substituent in the imino group plays an essential key role in the ROP of CL in terms of
一系列含有R 1(R 2)Al [O-2- t Bu-6-(C 6 F 5)N═CH} C 6 H 3 ] [R 1,R 2 =我,我(1a);Et,Et(1b); Me,Cl(1c)]和Me 2 Al [O-2- t Bu-6-(ArN═CH)C 6 H 3 ] [Ar = 2,6-F 2 C 6 H 3(2a),2, 4-F 2 C 6 H 3(3a),3,4-F 2 C 6 H 3(4a)]的制备和鉴定均基于NMR光谱和元素分析。它们的结构由X射线晶体学确定,这些配合物在Al周围折叠了扭曲的四面体几何形状。在PhCH 2 OH存在下,使用1a - c在
ε-己内酯(CL)上进行的开环聚合(ROPs)以活性方式有效地进行,并且所使用的阴离子供体
配体(Me,Et ,或Cl)。1a − 6a的催化活性[Ar = C 6 H 5(5a),2,6-Me 2 C 6 H 3(6a)]-PhCH 2