112197-45-2Relevant academic research and scientific papers
Rh(I)/(III)-N-Heterocyclic Carbene Complexes: Effect of Steric Confinement Upon Immobilization on Regio- and Stereoselectivity in the Hydrosilylation of Alkynes
Atwi, Boshra,Bauer, Matthias,Buchmeiser, Michael R.,Frey, Wolfgang,Nowakowski, Michal,Panyam, Pradeep K. R.,Ziegler, Felix
supporting information, p. 17220 - 17229 (2021/11/10)
Rh(I) NHC and Rh(III) Cp* NHC complexes (Cp=pentamethylcyclopentadienyl, NHC=N-heterocyclic carbene=pyrid-2-ylimidazol-2-ylidene (Py?Im), thiophen-2-ylimidazol-2-ylidene) are presented. Selected catalysts were selectively immobilized inside the mesopores
An alternative mechanistic paradigm for the β-Z hydrosilylation of terminal alkynes: The role of acetone as a silane shuttle
Iglesias, Manuel,Sanz Miguel, Pablo J.,Polo, Victor,Fernandez-Alvarez, Francisco J.,Perez-Torrente, Jesus J.,Oro, Luis A.
, p. 17559 - 17566 (2014/01/06)
The β-Z selectivity in the hydrosilylation of terminal alkynes has been hitherto explained by introduction of isomerisation steps in classical mechanisms. DFT calculations and experimental observations on the system [M(I)2{κ-C,C,O,O-(bis-NHC)}]BF4 (M=Ir (3 a), Rh (3 b); bis-NHC=methylenebis(N-2-methoxyethyl)imidazole-2-ylidene) support a new mechanism, alternative to classical postulations, based on an outer-sphere model. Heterolytic splitting of the silane molecule by the metal centre and acetone (solvent) affords a metal hydride and the oxocarbenium ion [R 3Si - O(CH3)2]+, which reacts with the corresponding alkyne in solution to give the silylation product [R 3Si - CHi£C - R]+. Thus, acetone acts as a silane shuttle by transferring the silyl moiety from the silane to the alkyne. Finally, nucleophilic attack of the hydrido ligand over [R3Si - CHi£C - R]+ affords selectively the β-(Z)- vinylsilane. The β-Z selectivity is explained on the grounds of the steric interaction between the silyl moiety and the ligand system resulting from the geometry of the approach that leads to β-(E)-vinylsilanes. Silanes catch the shuttle: An outer-sphere mechanism that explains the β-Z hydrosilylation of terminal alkynes based on the role of acetone as a silane shuttle is disclosed. Heterolytic splitting of the silane molecule by the metal centre and acetone affords a metal hydride and the oxocarbenium ion [R 3Si - O(CH3)2]+, which reacts with the alkyne in solution to give the silylation product [R3Si - CHi£C - R]+ (see figure).
Synthesis and characterization of a free phenylene bis(N-heterocyclic carbene) and its di-Rh complex: Catalytic activity of the di-Rh and CCC-NHC Rh pincer complexes in intermolecular hydrosilylation of alkynes
Andavan, Gurusamy Thangavelu Senthil,Bauer, Eike B.,Letko, Christopher S.,Hollis, T. Keith,Tham, Fook S.
, p. 5938 - 5947 (2007/10/03)
1,3-Bis(3-butylimidazolium-1-yl)benzene diiodide (1) was reacted with Li(2,2,6,6-tetramethylpiperidine) yielding the free bis-carbene, 1,3-bis(3-butylimidazol-2-ylidene-1-yl)benzene (3), which has been spectroscopically characterized. Combining the free b
