Enhanced Reactivity of Aluminum Complexes Containing P-Bridged Biphenolate Ligands in Ring-Opening Polymerization Catalysis

Frontiers in Chemistry

Xue-Ru Zou¹  Yu-Ning Chang¹  Lan-Chang Liang²  Kuo-Wei Huang³ 

[1] Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan;Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan;KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia;

关键词: aluminum;    biphenolate;    ring-opening polymerization;    lactone;    lactide;    catalyst;   

DOI  :  10.3389/fchem.2018.00607

来源: DOAJ

【 摘 要 】

Aluminum complexes containing [RP(O)(2-O-3,5-tBu2C6H2)2]2− [R = tBu (3a), Ph (3b)] have been synthesized, structurally characterized, and their reactivity studied in comparison with those of their [RP(2-O-3,5-tBu2C6H2)2]2− [R = tBu (2a), Ph (2b)] analogs. Treating AlMe3 with one equiv of H2[3a-b] in THF at 0°C affords quantitatively [3a-b]AlMe, subsequent reactions of which with benzyl alcohol in THF at 25°C generate {[3a-b]Al(μ2-OCH2Ph)}2. The methyl [3a-b]AlMe and the benzyloxide {[3a-b]Al(μ2-OCH2Ph)}2 are all active for catalytic ring-opening polymerization (ROP) of ε-caprolactone and rac-lactide (rac-LA). Controlled experiments reveal that {[3a]Al(μ2-OCH2Ph)}2 is competent in living polymerization. Kinetic studies indicate that [3a]AlMe, in the presence of benzyl alcohol, catalyzes ROP of rac-LA at a rate faster than [3b]AlMe and [2a]AlMe(THF) by a factor of 1.8 and 23.6, respectively, highlighting the profound reactivity enhancement in ROP catalysis by varying the P-substituents of these biphenolate complexes of aluminum.

【 授权许可】

Unknown