Preparation and Characterization of Aluminum Alkoxides and their Application to Ring‐Opening Polymerization of ϵ‐Caprolactones

Abstract

Abstract The reaction of 2‐methoxybenzyl alcohol with one molar equiv of R 2 AIX in diethyl ether at 0°C gives [(2‐MeOC 6 H 4 CH 2 ‐μ‐O)AlRX] 2 ( 1 : R = Et, X = Cl, 2 : R = X = Et). In addition, 2,4‐di‐ tert ‐butylphenol reacts with i Bu 3 Al affording a four‐coordinated aluminum compound [(μ‐2,4‐ t Bu 2 ‐C 6 H 4 O)Al( i Bu) 2 ] 2 ( 4 ). Single crystal X‐ray structure analysis of 4 shows a C 2h ‐symmetry with a planar Al 2 O 2 core. Ring‐opening polymerization (ROP) of caprolactones initiated by 1, 4 and [(μ‐OCH 2 C 6 H 4 OMe)Al( i Bu) 2 ] 2 ( 3 ) is performed and polyesters with narrow molecular weight distributions were obtained from the “living” ROP of caprolactones. 1 H NMR spectroscopic studies of PCL reveal that the initiator of 1 and 3 is through the Al‐OAr function, but the initiator of 4 is through the Al‐ i Bu group.