Cycloaddition Reactions of Epoxides and CO_(2)Catalyzed by Bifunctional Rare-Earth Metal Complexes Bearing Amino-Bridged Tris(phenolato)Ligands  

作　　者：Yongjie Chen Yanwei Wang Jun Nong Dan Yuan Yingming Yao 

机构地区：[1]Key Laboratory of Organic Synthesis of Jiangsu Province,College of Chemistry,Chemical Engineering and Materials Science,Dushu Lake Campus,Soochow University,Suzhou,Jiangsu,215123 China

出　　处：《Chinese Journal of Chemistry》2024年第14期1571-1581,共11页中国化学（英文版）

基　　金：the National Key R&D Program of China(2022YFF0709802);the National Natural Science Foundation of China(22271205);PAPD is gratefully acknowledged.

摘　　要：Eight zwitterionic rare earth metal complexes stabilized by amino-bridged tris(phenolato)ligands bearing quaternary ammonium side-arms were synthesized and characterized.These complexes were used as single-component catalysts for the cycloaddition of CO_(2)and epoxides,and their catalytic activities are obviously higher than those of their binary analogues.Further studies revealed that the halide anions(Cl^(–),Br^(–),I^(–))and the metal complexes influenced the catalytic activity,and the lanthanum complex bearing iodide anion showed the highest catalytic activity for this addition reaction.A variety of mono-substituted epoxides were converted to cyclic carbonates in good to excellent yields(55%—99%)with high selectivity(>99%)at 30℃and 1 bar CO_(2),whereas internal epoxides required higher both reaction temperatures(60—120℃)and catalyst loading(2 mol%)for high yields.The catalyst was recyclable for four times without noticeable loss of catalytic activity.Based on the results of kinetic studies and in℃situ IR reactions,a plausible reaction mechanism was proposed.

关 键 词：Bifunctional catalyst Carbon dioxide Cyclic carbonate Rare-earth metal Tris(phenolato)ligand Insertion Cycloaddition C1 building blocks 

分 类 号：O64[理学—物理化学]