reaction mechanism

Mechanistic Insight into the Ni-Catalyzed Kumada Cross-Coupling: Alkylmagnesium Halide Promotes C–F Bond Activation and Electron-Deficient Metal Center Slows Down β-H Elimination

The Ni-catalyzed Kumada–Tamao–Corriu (KTC) cross-coupling between aryl fluorides and alkyl Grignard reagents has been used to achieve a highly selective Csp2–Csp3 bond construction via the carbon–fluorine (C–F) bond activation. However, the detailed mechanism of this groundbreaking KTC reaction remains unclear. Herein, we perform a series of analyses by density functional theory (DFT) calculations in order to understand the reaction mechanisms for the selective activation of a highly inert C–F bond by Ni catalysts with bidentate phosphorus ligands.

Predicting Dinitrogen Activation by Borenium and Borinium Cations

Activation of thermodynamically stable and kinetically inert dinitrogen (N2) has been a great challenge due to a significantly strong triple bond. Recently, the experimental study on the N2 activation by boron species, a highly reactive two-coordinated borylene, broke through the limitation of traditional strategy of N2 activation by metal species. Still, the study on metal-free N2 activation remains undeveloped.

Theoretical Study on Reaction Mechanisms of Dinitrogen Activation and Coupling by Carbene-Stabilized Borylenes in Comparison with Intramolecular C-H Bond Activation

Dinitrogen (N2) activation is particularly challenging due to the significantly strong N≡N bond, let alone the catenation of two N2 molecules. Recent experimental study shows that cyclic (alkyl)(amino)carbene (CAAC)-stabilized borylenes are able to tackle N2 activation and coupling below room temperature. Here we carry out density functional theory calculations to explore the corresponding reaction mechanisms. The results indicate that the reaction barrier for the dinitrogen activation by the first borylene is slightly higher than that by the second borylene.

Phosphine-Stabilized Germylidenylpnictinidenes as Synthetic Equivalents of Heavier Nitrile and Isocyanide in Cycloaddition Reactions with Alkynes

The reactions of chlorogermylene MsFluindtBu-GeCl 1, supported by a sterically encumbered hydrindacene ligand MsFluindtBu, with NaPCO(dioxane)2.5 and NaAsCO(18-c-6) in the presence of trimethylphosphine afforded trimethylphosphine-stabilized germylidenyl-phosphinidene 2 and -arsinidene 3, respectively. Structural and computational investigations reveal that the Ge–E′ bond (E′ = P and As) features a multiple-bond character.

Predicting Dinitrogen Activation by Five-Electron Boron-Centered Radicals

Due to the high bond dissociation energy (945 kJ mol–1) and the large highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap (10.8 eV), dinitrogen activation under mild conditions is extremely challenging. On the other hand, the conventional Haber–Bosch ammonia synthesis under harsh conditions consumes more than 1% of the world’s annual energy supply. Thus, it is important and urgent to develop an alternative approach for dinitrogen activation under mild conditions.

Aromaticity-promoted CS2 Activation by Heterocycle-Bridged P/N-FLPs: A Comparative DFT Study with CO2 Capture

Carbon dioxide (CO2) capture has attracted considerable attention from both experimental and theoretical chemists. In comparison, Carbon disulfide (CS2) activation is less developed. Here, we carry out a thorough comparative density functional theory study to examine the reaction mechanisms of CS2 activation by five-membered heterocycles-bridged P/N frustrated Lewis pairs (FLPs).

Predicting Dinitrogen Activation via Transition Metal Involved [4 + 2] Cycloaddition Reaction

As the strongest triple bond in nature, the N≡N triple bond activation has always been a challenging project in chemistry. On the other hand, since the award of the Nobel Prize in Chemistry in 1950, Diels‐Alder reaction has served as a powerful and widely applied tool in the synthesis of natural products and new materials. However, the application of Diels‐Alder reaction to dinitrogen activation remains less developed.

Systematic Design of a Frustrated Lewis Pair Containing Methyleneborane and Carbene for Dinitrogen Activation

Activation of atmospherically abundant dinitrogen (N2) by metal-free species under mild reaction conditions has been one of the most challenging areas in chemistry for decades. Very recent but limited progress in N2 activation by boron species, including two-coordinated borylene and methyleneborane and three-coordinated borole and borane, has been made toward metal-free N2 activation.

Probing the origin of the stereoselectivity and enantioselectivity of cobalt-catalyzed [2 + 2] cyclization of ethylene and enynes

The cyclobutane unit is important to prepare complex natural products with biological activity due to the high ring strain. Among various approaches, [2 + 2] cycloaddition is one of the major strategies to prepare cyclobutane under light conditions. Recently, Rajanbabu's group reported tandem catalysis for asymmetric coupling of inactivated ethylene and enynes to functionalized cyclobutenes or cyclobutanes. However, the reaction mechanisms remain unproven.