Preparation and characterization of bisphenolato magnesium derivatives: anefficient catalyst for the ring-opening polymerization of ε-caprolactone andL-lactide

摘要

A series of magnesium complexes have been prepared and characterized, in which REDBP-Me)Mg(μ-OBn)]_2 (4) has shown high activity toward the ring-opening polymerization (ROP)of ε-caprolactone and L-lactide. 2,2'-Ethylidene-bis(4,6-di-tert-butylphenol)-monomethyl ether([EDBP-(Me)H]) is prepared by the reaction of 2,2'-ethylidene-bis(4,6-di-tert-butylphenol) (EDBP-H_2)with dimethyl sulfate. The reaction of [EDBP-(Me)H] with "Bu_2Mgyields [(EDBP-Me)Mg~nBu]_2, whichfurther reacts with benzyl alcohol and N,N-dimethylethylenediamine giving complexesREDBP-Me)Mg(μ-OBn)]_2 (4) and {[EDBP(Me)]Mg(μ-Me_2NCH_2CH_2NH)}_2(5), respectively.Experimental results indicate that the activity of complex 4 toward cyclic esters is higher than that of[( -EDBP)Mg]_2/(BnOH).