Reactions of 2,2‘-Methylenebis(4-chloro-6-isopropyl-3-methylphenol) and 2,2‘-Ethylidenebis(4,6-di-<i>tert</i>-butylphenol) with Mg<i>ⁿ</i>Bu₂: Efficient Catalysts for Ring-Opening Polymerization of ε-Caprolactone and<scp>l</scp>-Lactide

Abstract

Three novel magnesium aryloxides, [(MCIMP)2Mg2(THF)]2 (1), [(EDBP)Mg(Et2O)]2 (2), and [(EDBP)Mg(THF)]2 (3), have been synthesized by the reaction of 2,2‘-methylenebis(4-chloro-6-isopropyl-3-methylphenol) (MCIMP−H2) or 2,2‘-ethylidenebis(4,6-di-tert-butylphenol) (EDBP−H2) with MgnBu2 in diethyl ether or tetrahydrofuran, respectively. Experimental results show that 1−3 efficiently catalyze the ring-opening polymerization of ε-caprolactone and l-lactide in a controlled fashion, yielding polymers with very narrow polydispersity indexes in a wide range of monomer-to-initiator ratios. Compound 1 has paved a way to synthesize as much as 500-fold polymer chains of poly(ε-caprolactone) with a very narrow polydispersity index. In addition, block copolymers such as poly(ε-caprolactone)-b-poly(l-lactide), poly(ethylene glycol) methyl ether-b-poly(l-lactide), and polystyrene-b-poly(l-lactide) have also been prepared.