Bimetallic amine-bridged bis(phenolate) lanthanide aryloxides and alkoxides: synthesis, characterization, and application in the ring-opening polymerization of rac-lactide and rac-β-butyrolactone  

作　　者：NIE Kun FENG Tao SONG FengKui ZHANG Yong SUN HongMei YUAN Dan YAO YingMing SHEN Qi 

机构地区：[1]Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science,Soochow University [2]School of Chemistry and Chemical Engineering, Taishan University

出　　处：《Science China Chemistry》2014年第8期1106-1116,共11页中国科学（化学英文版）

基　　金：financial supported by the National Natural Science Foundation of China (20972108, 21174095, 21132002);a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD);the Qing Lan Project is gratefully acknowledged

摘　　要：A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL（THF）n]2 [Ln = Y（1）, Yb（2）, Sm（3）（n = 1） and La（4）（n = 2）, L = Me2NCH2CH2N{CH2-（2-O–C6H2–tBu2-3,5）}2] and alkoxides p-C6H4CH2[OLnL（THF）]2 [Ln = Y（5）, Yb（6）] supported by an amine-bridged bis（phenolate） ligand have been synthesized through one-pot reactions of Ln（C5H5）3（THF）, LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy（in the cases of 1, 4 and 5）. Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide（LA） and rac-β-butyrolactone（BBL）, except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA（Pr up to 0.99） and syndiotactic PHB（Pr ≈ 0.81） with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.

关 键 词：amine-bridged bis（phenolate） ligand bimetallic lanthanide aryloxides and alkoxides ring-opening polymerization stereoselectivity 

分 类 号：O641.4[理学—物理化学] O631.5[理学—化学]