Heavy-atom tunnelling in Cu(ii)N₆ complexes: theoretical predictions and experimental manifestation

Abstract

The degenerate rearrangement on Jahn-Teller distorted metal complexes is a promising reaction for the observation of significant heavy atom quantum mechanical tunnelling. Herein, a family of Cu(II)-N 6 complexes are theoretically proven to exhibit rapid dynamical Jahn-Teller tunneling even close to the absolute zero. The manifestation of our predictions apparently appeared in solid state EPR experimental measurements on [Cu(en) 3 ]SO 4 more than 40 years ago, without the authors realizing that it was a quantum outcome. † Electronic supplementary information (ESI) available: Energy benchmark, full rate constants and KIE tables, an example of Polyrate input les, and XYZ geometries. See

Jahn‐Teller Effects in a Vanadate‐Stabilized Manganese‐Oxo Cubane Water Oxidation Catalyst

“…We find a potential energy barrier of only 3 kcal/mol, which according to Eyring's equation corresponds to a life time of each JT arrangement of only 25 ps at 300 K. At the temperature used to record the crystal structure, [9] 150 K, the life time is still only about 7.5 ns, much shorter than the data collection time. There are even theoretical works [63] showing that tunneling can contribute to JT interconversion dynamics for such small barriers (about 2 kcal/mol in the cited work).…”

A Playground for Heavy Atom Tunnelling: Neutral Substitutional Defect Rearrangement from Diamondoids to Diamonds

“…The results are clear: larger structures lead to smaller distortions. [10] As with the trend of the energy barrier, the geometrical changes in the vicinity of the substitutional nitrogen beyond C 50 are almost constant, and therefore are also expected to be similar to NDs and diamond. If we would like to tune the reaction rate, we can do it by playing with the size of the small diamondoids.…”

“…QT contributions to the reaction rate are usually neglected for atoms heavier than hydrogen, but in the past years this assumption has shifted. Indeed, in the 21st century many molecular heavy atom QT driven reactions have been discovered [9–21] …”

“…Indeed, in the 21st century many molecular heavy atom QT driven reactions have been discovered. [9][10][11][12][13][14][15][16][17][18][19][20][21] In doped diamonds, nanodiamonds and diamondoids, the QT effect on the reaction rate might be striking due to the small distortions that these substitutions create, which is connected to low energy barriers. Evidently, In type Ib diamonds [4,22] (consisting of substitutional nitrogen), Ammerlaan and Burgemeister [23] measured the nitrogen's transition rate in the 78 K-200 K temperature range, and found a significant influence of QT.…”

Computational Evidence for Tunneling and a Hidden Intermediate in the Biosynthesis of Tetrahydrocannabinol

“…In the current work, the structure 1 Z -CH 3 was used in place of 1 to reduce the number of basis functions as well as high conformational freedom in the pentyl chain because the tunneling calculations are computationally demanding. They were carried out with POLYRATE and the GAUSSRATE interface to Gaussian 16 with the B3LYP functional. , Tunneling calculations based on POLYRATE have been applied widely. ,,,,,,,− POLYRATE begins by computing the minimum energy path (MEP), the steepest descent path, connecting the saddle point to reactants and products. The transition state is located using CVT at the point of maximum free energy along the MEP, which may deviate from the saddle point.…”