Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
Macromol Rapid Commun. 2018 Apr;39(8):e1800002. doi: 10.1002/marc.201800002. Epub 2018 Mar 5.
Chromium-based metal-organic framework (MOF) Cr-MIL-100/101 activated by activator and aluminum trialkyl compound serve as unique, highly efficient heterogeneous single-site catalysts for the controlled polymerization of isoprene, which not only exhibit quasi-living nature in isoprene polymerization but also unprecedentedly switch from cyclic to cis-1,4-selectivity depending on the activator used to yield low molecular weight cyclic PIPs or extremely high molecular weight cis-1,4-PIPs. Such heterogeneous Cr-MOF catalysts can be recycled approximately five times. Based on nitrogen sorption isotherm tests and powder X-ray diffraction, a cationic mechanism is suggested, in which the polymerization takes place inside the open nanochannels of MOF catalysts and the space confinement effect of narrow open nanochannels originated from the coordination of PhNMe from activator [PhNHMe ][B(C F ) ] with the multiple metal centers of MOF catalysts might give a rational explanation for such controlled adjustment on the PIP's structure and properties.
基于铬的金属-有机骨架（MOF）Cr-MIL-100/101 经活化剂和三烷基铝化合物活化，可用作异戊二烯可控聚合的独特、高效的多相单活性位催化剂，其不仅在异戊二烯聚合中表现出准活性，而且还根据所用的活化剂，从环状转变为顺式-1,4-选择性，从而得到低分子量环状 PIP 或极高分子量顺式-1,4-PIP。这种多相 Cr-MOF 催化剂可回收约 5 次。基于氮气吸附等温线测试和粉末 X 射线衍射，提出了一种阳离子机理，其中聚合发生在 MOF 催化剂的开放纳米通道内，而来自活化剂[PhNHMe][B(CF ) ]的 PhNMe 与 MOF 催化剂的多个金属中心的配位产生的狭窄开放纳米通道的空间限制效应可能为这种对 PIP 的结构和性能的控制调节提供了合理的解释。
