Synthesis, characterization of hetero-bimetallic complex and application in the polymerization of ε-caprolactone

The reaction of 2,2′-ethylidenebis(4,6-di-tert-butylphenol)(EDBP-H2) with sodium, Al(Me)3 and BnOH with a molar of ratio of 1:1:1:1 in THF gives hetero-bimetallic complex of [(EDBP)Al(CH3)(μ2-OBn)Na(THF)3](1) in 85% yield. In order to investigate the different anion effects on the ROP of ε-caprolactone, complexes [(EDBP)2Al][(Li)(THF)2] (2) and [(EDBP)2Al][(Na)(THF)2] (3) were prepared in an analogous manner to that of 1 in 63% and 71% yields respectively. Experimental results show that hetero-bimetallic complex 1 is an efficient catalyst for the ring-opening polymerization of ε-caprolactone.