Electronic Ligand Modifications on Cobalt Complexes and Their Application toward the Semi-Hydrogenation of Alkynes and Para-Hydrogenation of Alkenes
作者:Safiyah R. Muhammad、Joseph W. Nugent、Kenan Tokmic、Lingyang Zhu、Jumanah Mahmoud、Alison R. Fout
DOI:10.1021/acs.organomet.9b00337
日期:2019.8.26
The effect of the electronic modification of a bis(carbene) pincer ligand, (MesCCCR), on cobalt catalysis has been investigated. The pincer ligand was modified in the para position of the aryl backbone with a tert-butyl and trifluoromethyl moiety to yield the electronic variants that were applied toward the synthesis and characterization of several cobalt complexes, (MesCCCR)Co. The application of
Highly Stereoselective Formal [3 + 3] Cycloaddition of Enals and Azomethine Imines Catalyzed by <i>N</i>-Heterocyclic Carbenes
作者:Audrey Chan、Karl A. Scheidt
DOI:10.1021/ja0709167
日期:2007.5.1
are effective catalysts for generating homoenolate species from α,β-unsaturated aldehydes. The nucleophilic intermediate adds to azomethine imines, and the resulting activated carbonyl unit undergoes an intramolecular acylation event. This formal [3 + 3] cycloaddition between α,β-unsaturated aldehydes and azomethine imines catalyzed by NHC has been developed to give substituted pyridazinones in good to
Acceptorless Alkane Dehydrogenation Catalyzed by Iridium CCC-Pincer Complexes
作者:Anthony R. Chianese、Myles J. Drance、Kelsey H. Jensen、Samuel P. McCollom、Nevin Yusufova、Sarah E. Shaner、Dimitar Y. Shopov、Jennifer A. Tendler
DOI:10.1021/om4006577
日期:2014.1.27
Iridiumcomplexes of CCC-pincer bis-N-heterocyclic carbenes, including a newly synthesized trifluoromethyl-substituted complex, were examined as catalysts for the acceptorless dehydrogenation of cyclooctane and n-undecane. Up to 103 turnovers were observed for the dehydrogenation of cyclooctane, and up to 97 turnovers were observed for the dehydrogenation of n-undecane. The catalysts showed high initial
Iridium Complexes of CCC-Pincer N-Heterocyclic Carbene Ligands: Synthesis and Catalytic C−H Functionalization
作者:Anthony R. Chianese、Allen Mo、Nicole L. Lampland、Raymond L. Swartz、Paul T. Bremer
DOI:10.1021/om100302g
日期:2010.7.12
5-di-tert-butylphenyl side groups, reaction with [Ir(1,5-cyclooctadiene)Cl]2 in acetonitrile with either excess triethylamine or stoichiometric cesium fluoride as base gave neutral, iridium(III) pincer complexes of the formula Ir(CCC)HCl(MeCN), which were purified by chromatography on silica gel. Metalation failed under these conditions for a 2,6-diisopropylphenyl-substituted derivative. In combination with NaOtBu
合成了一系列四个间亚苯基桥联的双苯并咪唑氯化物,作为刚性,单阴离子,CCC钳形N杂环卡宾配体的前体。对于具有1,3,5-二甲苯基或3,5-二叔丁基苯基侧基的配体,可与乙腈中的[Ir(1,5-环辛二烯)Cl] 2与过量的三乙胺或化学计量的氟化铯反应得到式Ir(CCC)HCl(MeCN)的中性铱(III)钳形配合物,将其通过硅胶色谱法纯化。在这些条件下,2,6-二异丙基苯基取代的衍生物的金属化失败。这些配合物与NaO t Bu结合形成活性催化剂,用于在纯芳烃溶剂中进行环辛烷的无受体脱氢和芳烃CH硼化。
Monoanionic bis(carbene) pincer complexes featuring cobalt(<scp>I–III</scp>) oxidation states
作者:Abdulrahman D. Ibrahim、Kenan Tokmic、Marshall R. Brennan、Dongyoung Kim、Ellen M. Matson、Mark J. Nilges、Jeffery A. Bertke、Alison R. Fout
DOI:10.1039/c5dt04723d
日期:——
The synthesis and characterization of a series of cobalt complexes featuring a pincer bis(carbene) ligand of the meta-phenylene-bridged bis-N-heterocyclic carbene (ArCCC, Ar = 2,6-diispropylphenyl or mesityl) are reported. Cleavage of the aryl C–H bond of the ligand was achieved in a one-pot metalation procedure using Co(N(SiMe3)2)2(py)2, an equivalent of exogenous base, and trityl chloride to form