Investigation of relative stabilities of CPAM zirconium cycloalkylmethyl vs isomeric ω-alkenyl complexes: Crystal structures of the cyclobutylmethyl and cyclopentylmethyl complexes
Investigation of relative stabilities of CPAM zirconium cycloalkylmethyl vs isomeric ω-alkenyl complexes: Crystal structures of the cyclobutylmethyl and cyclopentylmethyl complexes
复制标题
CPAM 环烷基甲基锆与异构α-烯基配合物的相对稳定性研究：环丁基甲基和环戊基甲基配合物的晶体结构
DOI：
10.1016/j.poly.2022.116100
复制
发表时间：
2022
期刊：
影响因子：
2.6
通讯作者：
Sita, Lawrence R.
中科院分区：
文献类型：
--
作者：
Epshteyn, Albert;Zhang, Yonghui;Fettinger, James C.;Sita, Lawrence R.
环戊二烯酰胺化锆环烷基甲基配合物(CPAm)Zr(X)[CH_2(环-CmH_2m~(-1))](CPAm_2=η_5-C_5Me_5)[(N，N‘)-κ_2-N(Et)-C(Me)N(t-Bu)]的合成、结构表征和相对稳定性的研究对n=0(3a)，1(3b)和2(3c)进行了(CPAM)Zr(Cl)[CH2(CH2)nCH2CH2=1CH2].(CPAM)Zr(SiMe2Ph)Cl(7)通过氢解原位生成的(CPAM)Zr(X)Cl(X=H或D)(8)催化亚甲基环丙烷的氢锆化反应，为瞬时生成的1a的快速异构化提供了3adue的高产率。相反，通过亚甲基环丁烷8的氢锆化反应可以高产率地分离出晶体1b，并用X-射线结晶学对其结构进行了表征。1bin溶液的热解提供了3b的定量产率，而1c的定量生成是在添加离子对{(CPAM)Zr(Me)}{B(C6F5)4}10的催化下，通过3c的分子内环化反应实现的。1b还通过传统的甲基化反应得到了环丁基甲基络合物2b，其结构也通过X射线晶体分析进行了表征。在溶液中，2℃在25℃下热分解为难处理的混合物。最后，2b与化学计量的硼酸盐B1反应得到相应的离子对络合物：{(CPAM)Zr[CH2CH2CH2CH2=CH2]}{B(C6F5)4}(9)，其中末端的烯基与过渡金属中心分子内配位，通过1H核磁共振谱确定。文中还给出了用密度泛函理论(B3LYP/LANL2DZ(Zr)/6-31G**)对1bto3二聚反应和9的结构进行计算研究的结果。
Investigations of the syntheses, structural characterization, and relative stabilities of the cyclopentadienyl, amidinate Zr cycloalkylmethyl complexes, (CPAM)Zr(X)[CH2(cyclo-CmH2m-1)] (CPAM = (η5-C5Me5)[(N,N′)-κ2-N(Et)-C(Me)N(t-Bu)]) for X = Cl and m = 3 (1a), 4 (1b) and 5 (1c) and for X = Me, and m = 4 (2b), and of the corresponding isomeric ω-alkenyl complexes, (CPAM)Zr(Cl)[CH2(CH2)nCH2CH = CH2] for n = 0 (3a), 1 (3b) and 2 (3c), have been conducted. Hydrozirconation of methylenecyclopropane by (CPAM)Zr(X)Cl (X = H or D) (8), which is generated in situ through hydrogenolysis of the Zr-Si bond of (CPAM)Zr(SiMe2Ph)Cl (7), provided a high yield of3adue to rapid isomerization of transiently generated1a. In contrast, crystalline1bcould be isolated in high yield via hydrozirconation of methylenecyclobutane by8, and it has been structurally characterized by X-ray crystallography. Thermolysis of1bin solution provided a quantitative yield of3b, while quantitative production of1cwas achieved through intramolecular cyclization of3cby reversible chloride abstraction that was catalyzed by addition of the ion pair, {(CPAM)Zr(Me)}{B(C6F5)4}10. The cyclobutylmethyl complex2bwas also prepared from1bthrough traditional methylation using MeLi, and it too was structurally characterized by X-ray crystallography. In solution,2bthermally decomposes at 25 °C to an intractable mixture. Finally, reaction of2bwith a stoichiometric amount of the borateB1provided the corresponding ion pair complex, {(CPAM)Zr[CH2CH2CH2CH = CH2]}{B(C6F5)4} (9) in which the terminal alkenyl group is intramolecularly coordinated to the transition metal center as determined by1H NMR spectroscopy. The results of a DFT (B3LYP / LANL2DZ (Zr) / 6-31G**) computational investigation for the1bto3bisomerization and for the structure of9are also included.