Search results
Results from the WOW.Com Content Network
Hyperconjugation can be used to rationalize a variety of chemical phenomena, including the anomeric effect, the gauche effect, the rotational barrier of ethane, the beta-silicon effect, the vibrational frequency of exocyclic carbonyl groups, and the relative stability of substituted carbocations and substituted carbon centred radicals, and the thermodynamic Zaitsev's rule for alkene stability.
Adding the hydrogen ion to one carbon atom in the alkene creates a positive charge on the other carbon, forming a carbocation intermediate. The more substituted the carbocation, the more stable it is, due to induction and hyperconjugation. The major product of the addition reaction will be the one formed from the more stable intermediate.
This bonding pattern is also seen in trimethylaluminium, which forms a dimer Al 2 (CH 3) 6 with the carbon atoms of two of the methyl groups in bridging positions. This type of bond also occurs in carbon compounds, where it is sometimes referred to as hyperconjugation; another name for asymmetrical three-center two-electron bonds.
The Cieplak effect relies on the stabilizing interaction of mixing full and empty orbitals to delocalize electrons, known as hyperconjugation. [2] When the highest occupied molecular orbital of one system and the lowest unoccupied molecular orbital of another system have comparable energies and spatial overlap, the electrons can delocalize and sink into a lower energy level.
Negative hyperconjugation is seldom observed, though it can be most commonly observed when the σ *-orbital is located on certain C–F or C–O bonds. [ 3 ] [ 4 ] In negative hyperconjugation, the electron density flows in the opposite direction (from a π- or p-orbital to an empty σ * -orbital) than it does in the more common ...
Hyperconjugation can be used to explain phenomena such as the gauche effect and anomeric effect. Orbital symmetry is important when dealing with orbitals that contain directional components like p and d. An example of such an effect is square planar low-spin d 8 transition metal complexes. These complexes exist as square planar complexes due to ...
Here's how to distinguish "sundowning"—agitation or confusion later in the day in dementia patients—from typical aging, from doctors who treat older adults.
Hyperconjugation model for explaining the gauche effect in 1,2-difluoroethane There are two main explanations for the gauche effect: hyperconjugation and bent bonds . In the hyperconjugation model, the donation of electron density from the carbon–hydrogen σ bonding orbital to the carbon–fluorine σ * antibonding orbital is considered the ...