H/D Exchange Processes Catalyzed by an Iridium-Pincer Complex
摘要:
A PNP-pincer iridium dihydride performs the HID exchange between aromatic substrates and tertiary hydrosilanes and D2O or C6D6. Complete incorporation of deuterium into sterically accessible C-ar-H and Si-H bonds was observed at a moderate temperature of 80 degrees C.
Ligand survey results in identification of PNP pincer complexes of iridium as long-lived and chemoselective catalysts for dehydrogenative borylation of terminal alkynes
作者:Chun-I Lee、Jessica C. DeMott、Christopher J. Pell、Alyson Christopher、Jia Zhou、Nattamai Bhuvanesh、Oleg V. Ozerov
DOI:10.1039/c5sc02161h
日期:——
Following the report on the successful use of SiNN pincercomplexes of iridium as catalysts for dehydrogenative borylation of terminal alkynes (DHBTA) to alkynylboronates, this work examined a wide variety of related pincerligands in the supporting role in DHBTA. The ligand selection included both new and previously reported ligands and was developed to explore systematic changes to the SiNN framework
继关于成功使用铱的 SiNN 钳形配合物作为末端炔烃 (DHBTA) 脱氢硼化为炔基硼酸盐的催化剂的报告之后,这项工作研究了各种相关钳形配体在 DHBTA 中的支持作用。配体选择包括新的和以前报道的配体,旨在探索 SiNN 框架(8-(2-二异丙基甲硅烷基苯基)氨基喹啉)的系统变化。令人惊讶的是,只有二芳基氨基/双(膦) PNP 系统显示出任何 DHBTA 反应性。筛选中使用的特定 PNP 配体(带有两个二异丙基膦基侧供体)显示 DHBTA 活性低于 SiNN。然而,利用 PNP 系统提供的配体优化机会,通过磷取代的变化导致发现了一种催化剂,其活性、寿命和范围远远超过了原始 SiNN 原型。在模型 PNP 系统中制备了几种 Ir 配合物,并作为催化循环中的潜在中间体进行了评估。其中,(PNP)Ir 二硼基络合物和硼基亚乙烯基络合物显示出催化能力较差,因此可能不是催化循环的一部分。
Oxygen-Atom Transfer from Carbon Dioxide to a Fischer Carbene at (PNP)Ir
作者:Matthew T. Whited、Robert H. Grubbs
DOI:10.1021/ja801865c
日期:2008.5.1
the presence of t-butyl methyl ether leads to formation of an iridium(I) Fischer carbene complex, (PNP)Ir C(H)OtBu, by double C-H activation and loss of H2. The square planar pincer-type carbene effects quantitative oxygen-atom transfer from CO2 (1 atm) at ambient temperature to generate t-butyl formate and (PNP)Ir-CO. The iridium carbene reacts similarly with carbonyl sulfide and phenyl isocyanate, causing
Decarbonylation of ethanol to methane, carbon monoxide and hydrogen by a [PNP]Ir complex
作者:Jonathan G. Melnick、Alexander T. Radosevich、Dino Villagrán、Daniel G. Nocera
DOI:10.1039/b914083b
日期:——
The putative three-coordinate Ir(I) PNPPri (PNPPri = [N2-P(CHMe2)2-4-MeC6H3}2]–) pincer complex decarbonylates ethanol to yield methane, hydrogen and [PNPPri]Ir(CO). The mechanism involves the isolable trans-[PNPPri]Ir(H)(Me)(CO), which is susceptible to photochemical reductive elimination of methane.
Alkene Hydrosilation by a Cationic Hydrogen-Substituted Iridium Silylene Complex
作者:Elisa Calimano、T. Don Tilley
DOI:10.1021/ja803332h
日期:2008.7.1
charge is localized at the silicon center and depict a LUMO with predominant silicon p-orbital character. Notably, complex 2 reacts rapidly with unhindered alkenes at ambient temperatures to afford disubstituted silylene complexes via Si-C bond formation. Complex 2 is also the catalyst for alkene hydrosilation of primary silanes with a high degree of anti-Markovnikov selectivity.
Multiple C−H Activations of Methyl <i>tert-</i>Butyl Ether at Pincer Iridium Complexes: Synthesis and Thermolysis of Ir(I) Fischer Carbenes<sup>1</sup>
作者:Patricio E. Romero、Matthew T. Whited、Robert H. Grubbs
DOI:10.1021/om8003515
日期:2008.7.1
activation of methyl tert-butyl ether (MTBE) mediated by pincer iridium complexes derived from PNP and PCP frameworks has been studied. Double C−H activation of MTBE by these complexes leads to formation of Ir(I) Fischer carbenes of the type (pincer)Ir═C(H)OtBu via elimination of H2. In one case, the structure of the Fischer carbene has been confirmed by single-crystal X-ray analysis. For both systems
研究了由PNP和PCP骨架衍生的钳形铱配合物介导的甲基叔丁基醚(MTBE)的CH活化。这些配合物对MTBE的双重CHH活化作用是通过消除H 2形成(钳子)Ir═C(H)O t Bu型Ir(I)Fischer卡宾酯。在一种情况下,费歇尔卡宾的结构已经通过单晶X射线分析得到了证实。对于这两种系统,均以动力学产物形式获得了卡宾,并且长时间的热分解导致形成了热力学稳定的反式-(钳子)Ir(H)2(CO)复合物。提出了这种转化的机制以及支持该提案的反应性研究。