![1,3-bis[2,6-bis(1-methylethyl)phenyl]-1,3-dihydro-2H-imidazol-2-ylidene monohydrochloride](http://file1.lookchem.com/cas/reactions/2021/07/05/9596776.svg+xml_ms)
![[(IPr)Nb(=NMe)(NMe2)(μ-F)2(μ-NMe2)NbF2(NMe2)]](http://file1.lookchem.com/cas/reactions/2021/07/05/35514467.svg+xml_ms)
244187-81-3Relevant articles and documents
Expedient Access to Normal- and Abnormal- N-Heterocyclic Carbene (NHC) Magnesium Compounds from Imidazolium Salts
Ghadwal, Rajendra S.,Rottsch?fer, Dennis,Schürmann, Christian J.
, p. 1236 - 1240 (2016)
Treatment of imidazolium salts (IPrH)Cl (1) and (IPrH)I (2) with MeMgI leads to the formation of normal N-heterocyclic carbene (nNHC) compounds (IPr)MgCl(I) (3) and (IPr)MgI2(4) [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene], respectively. By employing a similar strategy, the first magnesium compound (aIPrPh)MgI2(OEt2) (6) featuring an abnormal-NHC [aIPrPh= 1,3-bis(2,6-diisopropylphenyl)-2-phenyl-imidazol-4-ylidene] is prepared by the treatment of a C2-arylated imidazolium salt (IPrPh)I (5) with MeMgI. While the deprotonation of 1 and 2 can be accomplished at room temperature, an elevated temperature is required to deprotonate 5 with MeMgI. This is most likely due to the higher pKavalue of the C4-H than that of the C2-H hydrogen atom. Salt metathesis reaction of 6 with KN(SiMe3)2cleanly leads to the formation of a magnesium amide derivative (aIPrPh)Mg{N(SiMe3)2}2(7). Compounds 3, 4, 6, and 7 were characterized by elemental analyses and NMR spectroscopic studies. The molecular structures of 3, 4, and 6 were determined by single-crystal X-ray diffraction analyses.
Binuclear Niobium Complex with Coordinated N-Heterocyclic Carbene
Petrov,Golubitskaya,Kompankov,Eltsov,Sukhikh,Sokolov
, p. 1989 - 1994 (2019)
By the interaction of Nb(NMe2)5 and 1,3-(2,6-diisopropylphenyl)imidazolium (IPr·HBF4) tetrafluoroborate a binuclear complex with coordinated N-heterocyclic carbene [(IPr)Nb(=NMe)(NMe2)(μ-F)2(μ-NMe2) NbF2(NMe2)] (1) is obtained. The reaction of Nb(NMe2)5 and 1,3-(2,4,6-trimethylphenyl)imidazolium (IMes·HBF4) tetrafluoroborate yields [(IMes)2H][NbF6] salt (2). The structure of the complexes is determined by single crystal X-ray diffraction.
Potential of Homogeneous Pd Catalyst Separation by Ceramic Membranes. Application to Downstream and Continuous Flow Processes
Ormerod, Dominic,Lefevre, Nicolas,Dorbec, Matthieu,Eyskens, Inge,Vloemans, Pieter,Duyssens, Karlien,Diez De La Torre, Veronica,Kaval, Nadya,Merkul, Eugen,Sergeyev, Sergey,Maes, Bert U. W.
, p. 911 - 920 (2016)
Successful chemical production of molecules while simultaneously reducing the environmental impact of the process relies not only on more efficient reactions but also on developments in reactor and separation technology. Recent decades have also witnessed a significant growth in industrial interest in solvent-based separations using membranes stable to organic solvents. The incorporation of membranes into a chemical process can be via a simple downstream processing method or an integrated reaction membrane method. This paper deals with homogeneous organometallic catalyzed reactions and probes the separation of a number of readily available palladium complexes from reaction mixtures with highly stable ceramic membranes. A number of different processing methods, namely, online, at-line, and off-line are compared and contrasted. A high rejection of Palladium species and consequently very low palladium contamination of reaction products with a single organic solvent nanofiltration (OSN) step has been demonstrated.
The Si2H radical supported by two N-heterocyclic carbenes
Arz, Marius I.,Schnakenburg, Gregor,Meyer, Andreas,Schiemann, Olav,Filippou, Alexander C.
, p. 4973 - 4979 (2016)
Cyclic voltammetric studies of the hydridodisilicon(0,II) borate [(Idipp)(H)SiIISi0(Idipp)][B(ArF)4] (1H[B(ArF)4], Idipp = C[N(C6H3-2,6-iPr2)CH]2, ArF = C6H3-3,5-(CF3)2) reveal a reversible one-electron reduction at a low redox potential (E1/2 = -2.15 V vs. Fc+/Fc). Chemical reduction of 1H[B(ArF)4] with KC8 affords selectively the green, room-temperature stable mixed-valent disilicon(0,I) hydride Si2(H)(Idipp)2 (1H), in which the highly reactive Si2H molecule is trapped between two N-heterocyclic carbenes (NHCs). The molecular and electronic structure of 1H was investigated by a combination of experimental and theoretical methods and reveals the presence of a π-type radical featuring a terminal bonded H atom at a flattened trigonal pyramidal coordinated Si center, that is connected via a Si-Si bond to a bent two-coordinated Si center carrying a lone pair of electrons. The unpaired electron occupies the SiSi π? orbital leading to a formal Si-Si bond order of 1.5. Extensive delocalization of the spin density occurs via conjugation with the coplanar arranged NHC rings with the higher spin density lying on the site of the two-coordinated silicon atom.
The synthesis and x-ray structure of trans-NiCl2(1,3-bis (2,6-diisopropylphenyl)imidazol-2-ylidene)2; attempts to polymerize olefins utilizing a nickel(II) complex of a sterically demanding N-heterocyclic carbene
MacKinnon, Amanda L.,Baird, Michael C.
, p. 114 - 119 (2003)
The compound trans-NiCl2(IPr)2 (IPr=1,3-bis (2,6-diisopropylphenyl)imidazol-2-ylidene) is synthesized and characterized crystallographically. In combination with MAO, it is converted to an intermediate which catalyses the dimerization of ethylene but which not the polymerization of ethylene, propylene or 1-hexene.
Stable Singlet Carbenes as Organic Superbases
Bertrand, Guy,Grotjahn, Douglas B.,Jazzar, Rodolphe,Junor, Glen P.,Vermersch, Fran?ois,Yazdani, Sima
supporting information, p. 27253 - 27257 (2021/11/22)
A simple experimental procedure for scaling carbene Br?nsted basicity is described. The results highlight the strong basicity of pyrazol-4-ylidenes, a type of mesoionic carbene, also named cyclic-bentallenes (CBA). They are more basic (pKaH >42.7 in acetonitrile) than the popular proazaphosphatrane Verkade bases, and even the Schwesinger phosphazene superbase P4(tBu). The basicity of these compounds can readily be tuned, and they are accessible in multigram quantities. These results open new avenues for carbon centered superbases.
Erratum: Synthesis of organic super-electron-donors by reaction of nitrous oxide with n-heterocyclic olefins (Journal of the American Chemical Society (2019) 141:43 (17112?17116) DOI: 10.1021/jacs.9b10660)
Eymann, Léonard Y. M.,Varava, Paul,Shved, Andrei M.,Curchod, Basile F. E.,Liu, Yizhu,Planes, Ophélie M.,Sienkiewicz, Andrzej,Scopelliti, Rosario,Fadaei Tirani, Farzaneh,Severin, Kay
supporting information, p. 1112 - 1112 (2020/02/13)
We realized that the legend of Figure S20 in the Supporting Information contains mistakes. The UV-vis spectrum of 5a was recorded at a lower concentration than indicated (0.023 mM instead of 0.06 mM), and the solvent used for the measurements was DMSO and not THF. The conclusions are not affected by this error. The Supporting Information has been corrected and is available.
