53172-95-5Relevant academic research and scientific papers
Hydrosilylation of Carbonyls Catalyzed by Hydridoborenium Borate Salts: Lewis Acid Activation and Anion Mediated Pathways
Rawat, Sandeep,Bhandari, Mamta,Porwal, Vishal Kumar,Singh, Sanjay
, p. 7195 - 7203 (2020)
The electronically unsaturated three-coordinated hydridoborenium cations [LBH]+[HB(C6F5)3]-(1) and [LBH]+[B(C6F5)4]-(2), supported by a bis(phosphinimino)amide ligand, were found to be excellent catalysts for hydrosilylation of a range of aliphatic and ar
Evidence of a Donor-Acceptor (Ir-H)→SiR3 Interaction in a Trapped Ir(III) Silane Catalytic Intermediate
Hamdaoui, Mustapha,Ney, Marjolaine,Sarda, Vivien,Karmazin, Lydia,Bailly, Corinne,Sieffert, Nicolas,Dohm, Sebastian,Hansen, Andreas,Grimme, Stefan,Djukic, Jean-Pierre
, p. 2207 - 2223 (2016/07/21)
The ionic iridacycle [(2-phenylenepyridine-κN,κC)IrCp?(NCMe)][BArF24] ([2][BArF24]) displays a remarkable capability to catalyze the O-dehydrosilylation of alcohols at room temperature (0.4 × 103 3, 8 × 103 i 5 h-1 for primary alcohols) that is explained by its exothermic reaction with Et3SiH, which affords the new cationic hydrido-Ir(III)-silylium species [3][BArF24]. Isothermal calorimetric titration (ITC) indicates that the reaction of [2][BArF24] with Et3SiH requires 3 equiv of the latter and releases an enthalpy of -46 kcal/mol in chlorobenzene. Density functional theory (DFT) calculations indicate that the thermochemistry of this reaction is largely dominated by the concomitant bis-hydrosilylation of the released MeCN ligand. Attempts to produce [3][BF4] and [3][OTf] salts resulted in the formation of a known neutral hydrido-iridium(III) complex, i.e. 4, and the release of Et3SiF and Et3SiOTf, respectively. In both cases formation of the cationic μ-hydrido-bridged bis-iridacyclic complexes [5][BF4] and [5][OTf], respectively, was observed. The structure of [5][OTf] was established by X-ray diffraction analysis. Conversion of [3][BArF24] into 4 upon reaction with either 4-N,N-dimethylaminopyridine or [nBu4][OTf] indicates that the Ir center holds a +III formal oxidation state and that the Et3Si+ moiety behaves as a Z-type ligand according to Green's formalism. [3][BArF24], which was trapped and structurally characterized and its electronic structure investigated by state-of-the-art DFT methods (DFT-D, EDA, ETS-NOCV, QTAIM, ELF, NCI plots and NBO), displays the features of a cohesive hydridoiridium(III)→silylium donor-acceptor complex. This study suggests that the fate of [3]+ in the O-dehydrosilylation of alcohols is conditioned by the nature of the associated counteranion and by the absence of Lewis base in the medium capable of irreversibly capturing the silylium species.
