Knowledge Bank

The most important barrier forming process in the dimethyl ether (DME) internal rotation can be represented by the following scheme: [FIGURE] Oxygen ($\sigma$) lone pair reorganization, which emerges as the most important barrier forming contribution, implies that complexing of DME with $H+$ or $H2O$ should drastically reduce the barrier. The mechanism of such reduction and the influence of protonation on the energetics of the internal rotation barrier height and shape will will be discussed. Potential surfaces of DME and protonated DME, obtained by different techniques, will be compared and analyzed from the viewpoints of NBO and symmetry partitioning, steric repulsion and delocalization effects.