苯胺基桥联双芳氧基稀土金属配合物的合成、表征及催化性能

Synthesis,Characterization and Catalytic Activity of Benzylamine-bridged Bis(phenolato) lanthanide Complexes

通过配体前体苯胺基桥联双酚(PhN{CH_(2)-(2-HO-C_(6)H_(2)-Bu_(2)-3,5)}_(2),L;H_(2))与三硅胺基稀土金属配合物的质子交换反应,合成了苯胺基桥联双芳氧基稀土金属配合物,发现反应介质对反应的产物有明显的影响。L^(1)H_(2)与Ln[N(TMS)_(2)](3)(μ-Cl)Li(THF);以物质的量比1∶1在甲苯中90℃下反应,可以得到预期的苯胺基桥联双芳氧基稀土金属胺化物L^(1)LnN(TMS);(THF)(Ln=Yb(1),Sm(2))。而L^(1)H_(2)与Sm[N(TMS)_(2)](3)(μ-Cl)Li(THF);以1∶1的物质的量比在四氢呋喃(THF)中50℃下反应,则得到钐-锂杂双金属配合物(THF)LiL_(2)Sm(3)。这些配合物均经过了红外光谱、元素分析和单晶结构测定的表征。发现配合物1和2可以有效地催化L-丙交酯和D,L-丙交酯的开环聚合,得到高相对分子质量的聚丙交酯。其中,配合物1对D,L-丙交酯的开环聚合显示很好的选择性,可以得到杂同含量(Pr)达到0.87的聚丙交酯。

Lanthanide metal complexes stabilized by benzylamine-bridged bis(phenolato) ligand,(PhN{CH_(2)-(2-O-C_(6)H_(2)-Bu;-3,5)};)(L~1),were synthesized by the reaction of the ligand precursor L~1H_(2)with lanthanide amide. The reaction media has profound influence on the reaction. The reaction of Ln[N(SiMe;)_(2)](3)(μ-Cl)Li(THF);with L~1H_(2)in a 1∶1 molar ratio is performed in toluene at 90 ℃ to give the desired benzylamine-bridged bis(phenolate) lanthanide amido complexes L~1LnN(SiMe;);(THF)(Ln =Yb(1),Sm(2)),while the same reaction of Sm[N(SiMe;)_(2)](3)(μ-Cl)Li(THF);with L~1H_(2)in a 1∶1 molar ratio in THF at 50 ℃ only gives the unexpected Sm-Li heterobimetallic complex(THF)LiL;~1 Sm(3). All of these complexes were characterized by IR,elemental analysis and single crystal X-ray diffraction. The catalytic activities of complexes 1 and 2 for the ring-opening polymerization of L-lactide and D,L-lactide were tested. It is found that these complexes are efficient initiators for lactide polymerization to give polylactide with high relative molecular mass. Complex 1 has good stereoselectivity for D,L-lactide polymerization to give syndio-rich polylactide(P;=0. 87).