二(芳氧基)稀土(Ⅱ)配合物催化ε-己内酯开环聚合

系统地研究了二（２，６ 二叔丁基 ４ 甲基酚基）钐［（ＡｒＯ）２Ｓｍ（ＴＨＦ）４］催化ε 己内酯的开环聚合，发现它具有很高的催化活性并显示“活性”聚合的特点，在甲苯中，当［Ｍ］／［Ｉ］＝２０００（摩尔比），６０℃，１ｈ，转化率可达９８％．并比较了不同的两价稀土化合物的催化活性．通过核磁分析末端基结构的方法，研究了（ＡｒＯ）２Ｓｍ催化己内酯开环聚合的引发机理，发现催化剂首先与己内酯反应，生成三价烯醇式稀土化合物，后者引发己内酯聚合．     

Crystallographic report: Crystal structure of tris(2,6‐di‐tert‐butyl‐4‐methylphenolato‐O) (tetrahydrofuran‐O) erbium toluene solvate

A low‐coordinate aryloxo erbium complex, [(ArO)₃Er(THF)](MePh), has been synthesized by the reaction of anhydrous ErCl₃ with three equivalents of NaOAr in tetrahydrofuran. The central erbium atom is coordinated by three oxygen atoms of the aryloxo ligands and one oxygen atom of the tetrahydrofuran molecule, resulting in a distorted tetrahedron. Copyright © 2004 John Wiley & Sons, Ltd.     

X-Ray Structure of 8-Quinolinolato Lanthanide Complex: (8-Quinolinolato)bis(2,6-di-tert-butyl-4-methylphenoxo)samarium

Ｉｎｔｒｏｄｕｃｔｉｏｎ8 Ｈｙｄｒｏｘｙｑｕｉｎｏｌｉｎｅｉｓａｃｌａｓｓｉｃａｌｃｈｅｌａｔｉｎｇａｇｅｎｔｆｏｒｔｒａｎｓｉｔｉｏｎｍｅｔａｌｓａｎｄｌａｎｔｈａｎｉｄｅｓ .Ｒｅｃｅｎｔｌｙｍｅｔａｌｃｏｍ ｐｌｅｘｅｓｉｎｃｏｒｐｏｒａｔｉｎｇ 8 ｑｕｉｎｏｌｉｎｏｌａｔｏｌｉｇａｎｄｓｈａｖｅｒｅｃｅｉｖｅｄｍｏｒｅａｎｄｍｏｒｅａｔｔｅｎｔｉｏｎ .Ｔｈｅｒｅｓｅａｒｃｈｉｎｔｅｒｅｓｔｐｒｏｂａｂｌｙａｒｉｓｅｓｆｒｏｍｔｗｏａｓｐｅｃｔｓ .Ｆｉｒｓｔ,8 ｑｕｉｎｏｌｉｎｏｌａｔｏｍｅｔ…     

Bis(amido)titanium complexes having chelating diaryloxo ligands bridged by sulfur or methylene and their catalytic behaviors for ring-opening polymerization of cyclic esters

A series of bis(dialkylamido) titanium complexes coordinated by O-E-O (E=S, CH₂) chelating bis(aryloxo) ligands, Ti[E(4-Me-6-^tBuC₆H₂O)₂](NR₂)₂ (1: E=S, R=Me; 2: E=S, R=Et; 3: E=CH₂, R=Me; 4: E=CH₂, R=Et), were synthesized by the reaction of Ti(NR₂)₄ (R=Me, Et) with 2,2^′-E(4-Me-6-^tBuC₆H₂OH)₂ (E=S, CH₂). The crystal structures of complexes 2 and 4 were determined by X-ray diffraction study. Complex 2 has a trigonal bipyramidal structure with the sulfur and nitrogen atom in trans positions and complex 4 has a tetrahedral structure. The complex 2 was found to initiate the controlled polymerization of ε-caprolactone in toluene at 100 °C affording poly(ε-caprolactone) and poly(l-lactide) with relatively narrow molecular weight distributions. The complex 4 showed higher activity for the polymerization of ε-caprolactone to give a polymer with a broader molecular weight distribution in comparison with complex 2.