A series of rare-earth(RE)metal complexes[RE=La(1,5,6),Nd(2),Sm(3),Y(4)]bearing polydentate N’-(2-aminoethyl)-N,N-dimethyl-1,2-ethylenediamine bridged-tris(phenolto)ligands were synthesized and characterized.The acti...A series of rare-earth(RE)metal complexes[RE=La(1,5,6),Nd(2),Sm(3),Y(4)]bearing polydentate N’-(2-aminoethyl)-N,N-dimethyl-1,2-ethylenediamine bridged-tris(phenolto)ligands were synthesized and characterized.The activity of complexes 1-6 for catalysing the cycloaddition reaction of CO_(2) and epoxides was studied,and the lanthanum complex 1 showed the highest activity.Under the conditions of 1 bar CO_(2) and 25℃,lanthanum complex 1 catalysed the reaction of 18 mono-substituted epoxides,generating cyclic carbonates in 50-99% yields.More importantly,it also catalysed reactions of 6 di-substituted epoxides under ambient conditions(1 bar CO_(2) and 25℃),and generated cyclic carbonates in 85-99% yields.This lanthanum complex is the first catalyst capable of converting di-substituted epoxides into internal cyclic carbonates under ambient conditions.Kinetic study was conducted to determine rate orders and Gibbs activation energy.A DFT study proved that poly(phenolto)ligands play vital roles in product dissociation.展开更多
基金the National Natural Science Foundation of China(21871198)the Major Research Project of the Natural Science of the Jiangsu Higher Education Institutions(19KJA360005,19KJA320007)PAPD.
文摘A series of rare-earth(RE)metal complexes[RE=La(1,5,6),Nd(2),Sm(3),Y(4)]bearing polydentate N’-(2-aminoethyl)-N,N-dimethyl-1,2-ethylenediamine bridged-tris(phenolto)ligands were synthesized and characterized.The activity of complexes 1-6 for catalysing the cycloaddition reaction of CO_(2) and epoxides was studied,and the lanthanum complex 1 showed the highest activity.Under the conditions of 1 bar CO_(2) and 25℃,lanthanum complex 1 catalysed the reaction of 18 mono-substituted epoxides,generating cyclic carbonates in 50-99% yields.More importantly,it also catalysed reactions of 6 di-substituted epoxides under ambient conditions(1 bar CO_(2) and 25℃),and generated cyclic carbonates in 85-99% yields.This lanthanum complex is the first catalyst capable of converting di-substituted epoxides into internal cyclic carbonates under ambient conditions.Kinetic study was conducted to determine rate orders and Gibbs activation energy.A DFT study proved that poly(phenolto)ligands play vital roles in product dissociation.
