Synthesis and Reactivity of Thermally Stable Zirconocene (II) Species Precursors

研究了氢化三茚基锆与各种炔的反应，并评价了锆配合物作为锆茂（II）当量的反应活性。三茚基氢化锆与内炔反应，高产率地得到相应的锆并环戊二烯。有趣的是，与末端芳基炔的反应高选择性地生成了2，5-二芳基锆杂环，由此得到的二茚基锆杂环戊二烯与四氯化钛反应，通过二烯部分与茚基配体的偶联得到相应的芴衍生物。该反应适用于烷基或芳基取代的双环锆并环戊二烯，并得到取代的芴。代替茚基配体，具有取代的茚基配体的锆并环戊二烯也用于反应，并得到相应的茚衍生物。的zirconacycloxyneenes与相关的结构参数的比较表明，耦合反应强烈的影响由茚基或茚基配体和zirconacycloxyneenes的二烯部分之间的距离。最具反应性的钛环戊二烯具有最短的距离。此外，反应性随着配体的空间体积的增加而增加。四氯化钛在反应中起着重要的氧化剂作用。

Reactions of tris (indenyl) zirconium hydride with a variety of alkynes were investigated and evaluated the reactivity of the zirconium complex as zirconocen (II) equivalent. The reaction of tris (indenyl) zirconium hydride with internal alkynes afforded the corresponding zirconacyclopentadienes in high yields. Interestingly, the reaction with terminal arylalkynes produced the2,5-diarylzirconacycles with high selectivity.A reaction of thus obtained bis (indenyl) zirconacyclopentadienes with titanium tetrachloride afforded the corresponding fluorene derivatives via coupling of the diene moiety with the indenyl ligand. This reaction was applicable for alkyl-or aryl-substituted, and bicyclic zirconacyclopentadienes and furnished the substituted fluorenes. Instead of the indenyl ligand, zirconacyclopentadienes having substituted cyclopentadienyl ligands were also applied for the reaction and afforded the corresponding indene derivatives. A comparison of the structural parameters of the zirconacyclopentadienes with the related ones suggested that the coupling reactivity was strongly affected by the distance between the indenyl or cyclopentadienyl ligands and the diene moiety of the zirconacyclopentadienes. The most reactive titanacyclopentadienes have the shortest distance. In addition, the reactivity was increased with increasing the steric bulkiness of the ligand. Titanium tetrachloride played an important role as an oxidant in the reaction.