Solvent molecules within zeolite pores provide interactions that influence the stability of reactive intermediates and impact rates and selectivities for catalytic reactions. We show the kinetic and thermodynamic consequences of these interactions and reveal their origins using alkene epoxidations in titaniumsubstituted *BEA (Ti-BEA) zeolites. Epoxidation turnover rates vary widely among primary n-alkenes (C 6 −C 18 ) in hydrophilic (Ti-BEA-OH) and hydrophobic (Ti-BEA-F) catalysts in aqueous acetonitrile (CH 3 CN). Apparent activation enthalpies (ΔH app ‡ ) and entropies (ΔS app ‡) increase with alkene carbon number in both catalysts; however, the span of ΔH app ‡ values in Ti-BEA-OH (68 kJ mol −1 ) greatly exceeds that in Ti-BEA-F (18 kJ mol −1 ). These trends, and commensurate gains in ΔS app ‡ , reflect the displacement and reorganization of solvent molecules that scale with the size of transition states and the numbers of solvent molecules stabilized by silanol defects near active sites. Experimental and computational assessments of intrapore solvent composition from 1 H NMR, infrared spectroscopy, and grand canonical molecular dynamics (GCMD) simulations show that Ti-BEA-OH uptakes larger quantities of both CH 3 CN and H 2 O than Ti-BEA-F. The Born−Haber decomposition of simulated enthalpies of adsorption (ΔH ads,epox ) for C 6 −C 18 epoxides attributes ΔH ads,epox that become more endothermic for larger adsorbates to the displacement of greater numbers of solvent molecules bound to silanol defects into the bulk solvent. A strong correlation between ΔH app ‡ and ΔH ads,epox (from GCMD and isothermal titration calorimetry) gives evidence that the disruption of solvent structures provides excess thermodynamic contributions (e.g., G ε ) that depend on the solvent composition in the pores, the excluded volume of reactive species, and the density of silanol groups near active sites. Altering G ε values offers opportunities to control selectivities and rates of reactions through the design of extended active site environments.

Homogeneous catalysts have rapid kinetics and keen reaction selectivity. However, their widespread use for industrial catalysis has remained limited because of challenges in reusability. Here, we propose a redox-mediated electrochemical approach for catalyst recycling using metallopolymer-functionalized electrodes for binding and release. The redox platform was investigated for the separation of key platinum and palladium homogeneous catalysts used in organic synthesis and industrial chemical manufacturing. Noble metal catalysts for hydrosilylation, silane etherification, Suzuki cross-coupling, and Wacker oxidation were recycled electrochemically. The redox electrodes demonstrated high sorption uptake for platinum-based catalysts ( Q max up to 200 milligrams of platinum per gram of adsorbent) from product mixtures, with up to 99.5% recovery, while retaining full catalytic activity over multiple cycles. The combination of mechanistic studies and electronic structure calculations indicate that selective interactions with anionic intermediates during the catalytic cycle played a key role in the separations. Last, continuous flow cell studies support the scalability and favorable technoeconomics of electrochemical recycling.

In this study, an attempt has been made to investigate the mechanistic pathway for the aerobic oxidation of alcohols over nitrogen-doped graphene using density functional theory methods employing a suitable model for graphene. The formation of activated oxygen species (AOS), upon oxidation, by dioxygen has been investigated with the aid of various possible nitrogen-doped models. The detailed reaction mechanism for the oxidation of benzyl alcohol and ethanol by the three AOS obtained in the present study has been unraveled. Results indicate that the ketonic oxygen species oxidizes aromatic alcohol with minimum activation energy of ∼26.5 kcal/mol. On the contrary, the activation energy for the oxidation of alkyl alcohol by AOS present at the center is the lowest, which is also similar to that of ketonic oxygen species. On the basis of the results, a generalized reaction mechanism has been arrived for alcohol oxidation by nitrogen-doped graphene. Findings reveal the valuable lead information for the optimal control over selective oxidation of alcohol by N-doped graphene based on dopant concentration and temperature

<p>Triterpenoids possess valuable medicinal properties ranging from anti-microbial to anti-cancer. Some of them were known for their activity against HIV, Ebola and Influenza viruses. In this study, 108 triterpenoids were screened for its potential usage as anti-viral drug against SARS-CoV-2, MERS and SARS coronaviruses, using molecular docking calculation against their main proteases (M^pro) and ADME based drug-likeliness parameters.<br></p>