Mono(amidinate) aluminum complexes showed high catalytic activity for the ring-opening polymerization of e-caprolactone in toluene at ambient temperature. Monomer conversion up to 91％ could be reached within 1 h when using [{PhC(N-2.6-iPr2C6H3)2}AlMe2] (C1) as initiator at 25 ℃. The electron-donating groups on the ortho-positions of the N-substituted phenyl ring were superior to the electron-withdrawing groups for the enhancement of the catalytic activity, but both brought an increase in activity when compared with the un-substituted complex C7. The complexes bearing two ortho-substituents on one of the N-phenyl rings were more active than the analogues bearing one ortho-substituent. Although high molecular weight poly(ε-caprolactone)s were obtained by using these aluminum catalysts, the polymerization of ε-caprolactone was not well controlled as indicated by the broad molecular weight distributions (PDI = 1.43-1.85) and the deviation of the number average molecular weight from the theoretical values. Sequential copolymerization of ε-caprolactone and rac-lactide using mono(amidinate) aluminum complexes afforded poly(ε-caprolactone)-poly(rac-lactide) diblock copolymer, which was characterized well by NMR spectroscopy and gel permeation chromatography analysis.%将单脒基铝络合物用于催化6-己内酯(e-CL)开环聚合反应,结果表明,该类铝络合物表现出很高的催化活性:25℃时络合物({PhC(N-2,6-iPr2C6H3)2)A1Me2](Cl)催化ε-CL聚合1h,单体转化率为91%;70℃时络合物[{PhC(N-2,6-iPr2C6H3)-(N-2,6-Me2C6H3)}AlMe2](C2)催化ε-CL聚合15min,单体转化率达100%.脒基N-芳环上取代基的引入能明显提高催化剂活性,N-芳环邻位双取代的单脒基铝络合物的催化活性高于邻位单取代的.所得聚合物的分子量大于理论值,且分子量分布较宽(PDI=1.43～1.85),说明聚合的可控度不高.单脒基铝络合物可通过先催化ε-CL聚合,再引发外消旋丙交酯聚合,得到聚己内酯和聚丙交酯的两嵌段共聚物.
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