• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>European journal of inorganic chemistry >A calix[4]arene monoalkyl ether as a model of a tris(phenolate) ligand with a hemilabile anisole moiety: Syntheses, molecular structures and bonding of calix[4]arene ether supported titanium complexes and their catalytic activity in epoxidation react
【24h】

A calix[4]arene monoalkyl ether as a model of a tris(phenolate) ligand with a hemilabile anisole moiety: Syntheses, molecular structures and bonding of calix[4]arene ether supported titanium complexes and their catalytic activity in epoxidation react

机译：杯[4]芳烃单烷基醚作为具有半不稳定茴香醚部分的三（酚盐）配体的模型：杯[4]芳烃醚负载的钛配合物的合成，分子结构和键合及其在环氧化反应中的催化活性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

New mononuclear titanium complexes [TiCl(Rcalix)] [R = Me (1), Bz (2), SiMe3 (3)] supported by p-tert-butylcalix[4]arene mono(organyl)ethers (Rcalix) were prepared in good yield from H(2)R(2)calix and [TiCl4(THF)(2)]. The crystallographically characterized complex [TiCl(Mecalix)] (1) reacts readily with NaCp and LiNR2 to afford the complexes [TiCp(Mecalix)] (4) and [Ti(NR2)(Mecalix)] [R = Me (5), Et (6), iPr (7), Ph (8)], respectively. Reactions of [Ti(NR2)(Mecalix)] (5) with alcohols, phenols and thiols proceed cleanly with amide exchange, as exemplified by the synthesis of [Ti(OR)(Mecalix)] [R = Me (10), iPr (11), tBu (12), 4-tBuC(6)H(4) (13), 2,6-iPr(2)C(6)H(3) (14)], and [Ti(StBu)(Mecalix)] (15). Depending on the steric demand of the ligand coordinated to the [Ti(Mecalix)] complex fragment these compounds are monomeric or dimeric in the solid state, as demonstrated by the molecular structures of monomeric [Ti(OC6H3-2,6-iPr(2))(Mecalix)] (14) and [Ti(StBu)(Mecalix)] (15), or dimeric [{Ti(OMe)(Mecalix)}(2)] (10). In all complexes the calix[4]arene ligand adopts an elliptically distorted cone conformation in which the distance of the titanium atom from the anisole oxygen atom varies between 2.342 Angstrom and 2.438 Angstrom for the structurally characterized complexes, with the exception of the Cp complex 4. MP2 calculations on model complexes demonstrate that the titanium-anisole oxygen bond is weak, with a particularly shallow potential energy surface in the region between 2.30 Angstrom and 2.80 Angstrom The Mecalix ligand system therefore might be described as a tris(phenolate) ligand with a hemilabile anisole group in the titanium compounds reported. Despite the labile anisole ether titanium bond, isomerization of the calix[4]arene ligand to a paco coordination mode, as described earlier for the Me(2)calix complexes [Ti(OC6H4-4-R)(2)(Me(2)calix)], has not been observed in these complexes. Preliminary results on the catalytic epoxidation of cyclooctene with TBHP using calix[4]arene-stabilized titanium(iv) complexes are also briefly presented. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
机译：制备了新的单核钛配合物[TiCl（Rcalix）] [R = Me（1），Bz（2），SiMe3（3）]，由对叔丁基杯[4]芳烃单（有机基）醚（Rcalix）负载。 H（2）R（2）calix和[TiCl4（THF）（2）]的产率高。晶体学表征的配合物[TiCl（Mecalix）]（1）容易与NaCp和LiNR2反应，得到配合物[TiCp（Mecalix）]（4）和[Ti（NR2）（Mecalix）] [R = Me（5）， Et（6），iPr（7），Ph（8）]。 [Ti（NR2）（Mecalix）]（5）与醇，酚和硫醇的反应在酰胺交换下进行得很干净，例如[Ti（OR）（Mecalix）]的合成[R = Me（10），iPr （11），tBu（12），4-tBuC（6）H（4）（13），2,6-iPr（2）C（6）H（3）（14）]和[Ti（StBu） （Mecalix）]（15）。取决于配位到[Ti（Mecalix）]复杂片段的配体的空间需求，这些化合物是固态的单体或二聚体，如单体[Ti（OC6H3-2,6-iPr（2） ））（Mecalix）]（14）和[Ti（StBu）（Mecalix）]（15）或二聚体[{Ti（OMe）（Mecalix）}（2）]（10）。在所有络合物中，杯形[4]芳烃配体均采用椭圆形扭曲的圆锥构象，其中除结构复杂的Cp络合物外，钛原子与苯甲醚氧原子的距离在2.342埃和2.438埃之间变化。在模型配合物上的MP2计算表明，钛-茴香醚的氧键很弱，在2.30埃和2.80埃之间的区域具有特别浅的势能面。因此，Mecalix配体体系可以描述为具有报道了钛化合物中的半不稳定茴香醚基团。尽管有不稳定的茴香醚醚钛键，但杯形[4]芳烃配体异构化为paco配位模式，如先前针对Me（2）杯复杂[Ti（OC6H4-4-R）（2）（Me（2 ）calix）]，尚未在这些复合物中观察到。还简要介绍了使用杯[4]芳烃稳定的钛（iv）配合物用TBHP催化环辛烯催化环氧化的初步结果。 （C）Wiley-VCH Verlag GmbH＆Co.KGaA，69451 Weinheim，Germany，2004。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号