2,3-Bis[(2,6-diisopropylphenylimino)butane] nickel/MAO system toward ethylene polymerization displays two active sites with ultraviolet absorption bands at 456 nm and 492 nm to produce branched polyethylenes, respectively. It is surprising that adding ZnEt₂ results in selective catalyst active site to modulate polyethylene microstructure. 200 equiv. of ZnEt₂ causes a more than 30% decrease of branching degree from 140 to 97. The UV,EPR and CV results suggest that the active site at 456 nm is easily reduced by ZnEt₂. However, the active site at 492 nm still exhibits high catalytic activity, producing polyethylenes with a relatively low branching degree.

用于乙烯聚合的2,3-双[（2,6-二异丙基苯基亚氨基）丁烷]镍/ MAO体系显示出两个活性位点，分别在456 nm和492 nm处具有紫外线吸收带，可生产支链聚乙烯。令人惊讶的是，添加ZnEt ₂导致选择性的催化剂活性位点来调节聚乙烯的微观结构。200当量 ZnEt ₂引起的支化度从140降低到97，降低幅度超过30％。UV，EPR和CV结果表明ZnEt ₂易于还原456 nm处的活性位点。然而，在492nm处的活性位仍然表现出高催化活性，从而产生具有相对低的支化度的聚乙烯。