The borane B(C(6)F(5))(3) is a precatalyst for H/Dexchange between H(2) and deuterium-labeled silanes (D(3)SiPh, D(2)SiMePh, DSiMe(2)Ph, DSiEt(3)). Experimental and DFT studies reveal that B(C(6)F(5))(3) itself cannot activate dihydrogen but converts to HB(C(6)F(5))(2) under the action of hydrosilane. The latter species easily activates H-H and Si-H bonds by a σ-bond metathesis mechanism, which was further confirmed by the reactions of BD(3)·THF with H(2).
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http://dx.doi.org/10.1021/ja300365s | DOI Listing |
J Phys Chem A
March 2024
Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, 710127 Xi'an, P. R. China.
Chemical reactions with submerged barriers may feature interesting dynamic behaviors that are distinct from those with substantial barriers or those entirely dominated by capture. The Si + HO reaction is a prototypical example, involving even two submerged saddle points along the reaction path: one for the direct dissociation of H (H-dissociation SP) and another for H migration from the O-side to the Si-side (H-migration SP). We investigated the intricacies of this process by employing quasi-classical trajectory calculations on an accurate, full-dimensional ab initio potential energy surface.
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February 2024
Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Sendai, Miyagi, 980-8578, Japan.
Chemistry
October 2022
Institute of Chemistry - Inorganic Chemistry, University of Graz, Schubertstraße 1, 8010, Graz.
Molybdenum(VI) bis(imido) complexes [Mo(NtBu) (L ) ] (R=H 1 a; R=CF 1 b) combined with B(C F ) (1 a/B(C F ) , 1 b/B(C F ) ) exhibit a frustrated Lewis pair (FLP) character that can heterolytically split H-H, Si-H and O-H bonds. Cleavage of H and Et SiH affords ion pairs [Mo(NtBu)(NHtBu)(L ) ][HB(C F ) ] (R=H 2 a; R=CF 2 b) composed of a Mo(VI) amido imido cation and a hydridoborate anion, while reaction with H O leads to [Mo(NtBu)(NHtBu)(L ) ][(HO)B(C F ) ] (R=H 3 a; R=CF 3 b). Ion pairs 2 a and 2 b are catalysts for the hydrosilylation of aldehydes with triethylsilane, with 2 b being more active than 2 a.
View Article and Find Full Text PDFChem Soc Rev
April 2022
Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Songhu Road 2005, Shanghai, 200438, P. R. China.
Borenium ions are strong Lewis acids because of the positive charge on boron. While their high reactivity had long restricted their role in organic synthesis to stoichiometric reagents, in the past ten years the introduction of suitable supporting ligands, such as N-heterocyclic carbenes, has enabled them to function as competent catalysts for various organic transformations involving the activation of strong covalent bonds, such as H-H, Si-H, B-H, C-H and C-C bonds. This review provides an overview of the recent advances in borenium-catalysed reactions with emphasis on catalyst synthesis, methodology development and mechanistic insight.
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April 2021
Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, Texas, USA.
The intramolecular "inverse" frustrated Lewis pairs (FLPs) of general formula 1-BR -2-[(Me N) C=N]-C H (3-6) [BR =BMes (3), BC H , (4), BBN (5), BBNO (6)] were synthesized and structurally characterized by multinuclear NMR spectroscopy and X-ray analysis. These novel types of pre-organized FLPs, featuring strongly basic guanidino units rigidly linked to weakly Lewis acidic boryl moieties via an ortho-phenylene linker, are capable of activating H-H, C-H, N-H, O-H, Si-H, B-H and C=O bonds. 4 and 5 deprotonated terminal alkynes and acetylene to form the zwitterionic borates 1-(RC≡C-BR )-2-[(Me N) C=NH]-C H (R=Ph, H) and reacted with ammonia, BnNH and pyrrolidine, to generate the FLP adducts 1-(R HN→BR )-2-[(Me N) C=NH]-C H , where the N-H functionality is activated by intramolecular H-bond interactions.
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