Mechanistic Insights into the Directed Hydrogenation of Hydroxylated Alkene Catalyzed by Bis(phosphine)cobalt Dialkyl Complexes

The mechanism of directed hydrogenation of hydroxylated alkene catalyzed by bis­(phosphine)cobalt dialkyl complexes has been studied by DFT calculations. The possible reaction channels of alkene hydrogenation catalyzed by catalytic species (<b>0</b>_<b>T</b>, <b>0</b>_<b>P</b>, and <b>0</b>) were investigated. The calculated results indicate that the preferred catalytic activation processes undergo a 1,2 alkene insertion. <b>0</b>_<b>P</b> and <b>0</b> prefer the β hydrogen elimination mechanism with an energy barrier of 9.5 kcal/mol, and <b>0</b>_<b>T</b> prefers the reductive elimination mechanism with an energy barrier of 11.0 kcal/mol. The second H₂ coordination in the σ bond metathesis mechanism needs to break the agostic H²–βC bond of metal–alkyl intermediates (<b>2</b>_<b>1P</b> and <b>2</b>_<b>1T</b>), which owns the larger energetic span compared to the reductive elimination. This theoretical study shows that the most favorable reaction pathway of alkene hydrogenation is the β hydrogen elimination pathway catalyzed by the planar (dppe)­CoH₂. The hydrogenation activity of Co­(II) compounds with redox-innocent phosphine donors involves the Co(0)–Co­(II) catalytic mechanism

Mechanistic Studies on the Carboxylation of Hafnocene and <i>ansa</i>-Zirconocene Dinitrogen Complexes with CO₂

A DFT study on the carboxylation of hafnocene and <i>ansa</i>-zirconocene dinitrogen complexes with CO₂ indicates that the most favorable initial CO₂ insertion into M–N (M = Hf, Zr) proceeds by a stepwise path rather than a concerted [2 + 2] path. The calculated results explain the regioselectivity of the N–C formation in experiments. In addition, a comparative analysis of ring tension and charge distribution unveils the different activities of N–N bond cleavage in the CO and CO₂ direct N–C bond formation reactions

Homolytic or Heterolytic Dihydrogen Splitting with Ditantalum/Dizirconium Dinitrogen Complexes? A Computational Study

Transition metal complexes play a key role in creating efficient molecular catalysis processes leading to the ammonia production from earth-abundant dinitrogen. It is indispensable to examine the mechanism and influence of transition metal complexes on dinitrogen hydrogenation. In this paper, the mechanism of the dinitrogen hydrogenation triggered by bimetallic complexes [L₂M]₂(μ-η²:η²-N₂) (M = Ta and Zr, L = Sita-type or Chirik-type ligand) is investigated by density functional theory calculation. Our results show that the side-on ditantalum dinitrogen complex with Sita-type ligands favors the pathway of homolytic dihydrogen splitting when hydrogenation products are generated. However, the dihydrogen splitting switches to the heterolytic pathway as the dominant mechanism when Zr is the metal center. The ditantalum dinitrogen complex undergoes hydrogenation much easier from the side-on coordination mode than the side-on-end-on mode with Sita-type or Chirik-type ligands. With these findings from the computational study, this work identifies that different metal centers and coligands (Sita-type or Chirik-type) in different binding modes (side-on-end-on or side-on bridged) dictate the pathway of dihydrogen cleavage triggered by the bimetallic complexes. This work should provide insights on factors impacting the dinitrogen hydrogenation process and shed light on designing new transition metals and ligands for dinitrogen hydrogenation catalysts in the future

DFT Study on the Mechanism of Tandem Oxidative Acetoxylation/Ortho C–H Activation/Carbocyclization Catalyzed by Pd(OAc)₂

A density functional theory (DFT) study has been conducted to unveil the mechanisms of tandem oxidative acetoxylation/ortho C–H activation/carbocyclization catalyzed by Pd­(OAc)₂. The potential competitive reaction pathways between oxidative acetoxylation and ortho C–H activation, C–H activation with outer-sphere and inner-sphere acetate ligands, and the role of DMSO in the reaction have been discussed in detail. The calculated results indicate that the oxidative acetoxylation proceeds before ortho C–H activation in this tandem reaction in a neutral system without DMSO as a ligand coordinated to Pd. A six-membered transition state is proposed in the oxidative acetoxylation step, and a six-membered transition state is proposed in the palladium carboxylate catalyzed sp² C–H activation step. The coordination of outer-sphere acetate ion to Pd decreases the energy barrier of the step of ortho sp² C–H activation. In addition, this theoretical work demonstrates that the cosolvent DMSO as a ligand coordinated with Pd decreases the energy barrier of C–H activation. Also, the reaction tandem sequence changes to ortho C–H activation/oxidative acetoxylation/carbocyclization induced by DMSO as a ligand coordinated with Pd

DFT Study on the Mechanism of Tandem Oxidative Acetoxylation/Ortho C–H Activation/Carbocyclization Catalyzed by Pd(OAc)₂

A density functional theory (DFT) study has been conducted to unveil the mechanisms of tandem oxidative acetoxylation/ortho C–H activation/carbocyclization catalyzed by Pd­(OAc)₂. The potential competitive reaction pathways between oxidative acetoxylation and ortho C–H activation, C–H activation with outer-sphere and inner-sphere acetate ligands, and the role of DMSO in the reaction have been discussed in detail. The calculated results indicate that the oxidative acetoxylation proceeds before ortho C–H activation in this tandem reaction in a neutral system without DMSO as a ligand coordinated to Pd. A six-membered transition state is proposed in the oxidative acetoxylation step, and a six-membered transition state is proposed in the palladium carboxylate catalyzed sp² C–H activation step. The coordination of outer-sphere acetate ion to Pd decreases the energy barrier of the step of ortho sp² C–H activation. In addition, this theoretical work demonstrates that the cosolvent DMSO as a ligand coordinated with Pd decreases the energy barrier of C–H activation. Also, the reaction tandem sequence changes to ortho C–H activation/oxidative acetoxylation/carbocyclization induced by DMSO as a ligand coordinated with Pd

Additional file 1 of Identification of potential crucial genes and therapeutic targets for epilepsy

Additional file 1: Table S1. 91 DEGs were identified in GSE44031 series