English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The ability of cucurbit[6]uril () and cucurbit[7]uril () to catalyze the thermally activated 1,2-methyl shift isomerization pathway of -xylene in vacuum is investigated using infrequent metadynamics.  is predicted to effectively and selectively catalyze the meta-to-para isomerization through stabilization of the transition state (TS) by van der Waals push (packing coefficient ≈74%), while inhibiting the meta-to-ortho pathway by molding effects of the cavity. Interestingly, despite the snug binding, a very low rate of host-guest vibrational energy transfer is revealed using a novel approach of host-guest partition of the mode-specific anharmonic relaxation rates and  molecular dynamics. The weak vibrational coupling suggests that CB can act as a thermal buffer, possibly shielding encapsulated guests from outside vibrational perturbations such as solvent effects. This dynamic effect could provide an additional boost to the reaction rate by blocking the occurrence of reaction barrier recrossing caused by the friction with surrounding molecules. Finally, mean residence times of xylene into the hosts' cavity were estimated for a range of host-guest complexes, revealing a highly dynamic equilibrium allowing very high guest turnover rates that could minimize catalyst inhibition effects commonly suffered by other supramolecular catalysts.

journal of physical chemistry. c./journal of physical chemistry. c

Supramolecular Catalysis of <i>m</i>-Xylene Isomerization by Cucurbiturils: Transition State Stabilization, Vibrational Coupling, and Dynamic Binding Equilibrium

Supramolecular Catalysis of m-Xylene Isomerization by Cucurbiturils: Transition State Stabilization, Vibrational Coupling, and Dynamic Binding Equilibrium