Syntheses and Structures of Five-Coordinate Zirconium Alkyl Complexes Supported by Diketiminate Ligands
Syntheses and Structures of Five-Coordinate Zirconium Alkyl Complexes Supported by Diketiminate Ligands
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二酮亚胺配体负载的五配位烷基锆配合物的合成与结构
DOI：
10.1021/om980950h
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发表时间：
1999
期刊：
影响因子：
2.8
通讯作者：
D. Motry
中科院分区：
文献类型：
--
作者：
B. Qian;W. J. Scanlon;Milton R. Smith;D. Motry
烷烃消除反应由Zr（CH 2 Ph）4和TTPH（TTPH = 2-对甲苯基氨基-4-对甲苯基亚氨基-2-戊烯）生成二酮亚胺化合物（TTP）Zr（CH 2 Ph）3（1）。解析了化合物1的分子结构，结果表明化合物1是一个五配位的锆配体，其中三个苄基为η1配位，一个TTP配体为η2配位。当1在烃溶剂中加热至45 °C时，甲苯被消除，并形成邻苯二甲酸化产物2。2的分子结构表示η1和η2苄基。变温1H NMR（−78至50 °C）光谱显示单一苄基共振。苄基亚甲基共振的1 JCH的大小与溶液中η1和η2键合模式之间的快速交换一致。使用（PPP-d10）Zr（CH 2 Ph）3（3-d10，PPP = 2-phenylamino-4-phenylimino-2-pentenato）的同位素标记实验支持通过四中心过渡态直接活化C-H。基于动力学实验，C-H活化是单分子的，限速步骤表现出很大的动力学…
An alkane elimination reaction generates the diketiminate compound (TTP)Zr(CH2Ph)3 (1) from Zr(CH2Ph)4 and TTPH (TTPH = 2-p-tolylamino-4-p-tolylimino-2-pentene). The molecular structure of 1 was solved, and it shows a five-coordinate zirconium with three η1-coordinated benzyl groups and an η2-bound TTP ligand. When 1 is heated to 45 °C in hydrocarbon solvents, toluene is eliminated and the orthometalated product 2 is formed. The molecular structure of 2 indicates η1 and η2 benzyl groups. The variable-temperature 1H NMR (−78 to 50 °C) spectra exhibit a single benzyl resonance. The magnitude of 1JCH for the benzyl methylene resonance is consistent with a rapid exchange between η1 and η2 bonding modes in solution. Isotopic labeling experiments employing (PPP-d10)Zr(CH2Ph)3(3-d10, PPP = 2-phenylamino-4-phenylimino-2-pentenato) support direct C−H activation through a four-centered transition state. Based on kinetic experiments, C−H activation is unimolecular, and the rate-limiting step exhibits a large kinetic...