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.
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 ...
In 1935 Baker and Nathan explained the observed difference in terms of a conjugation effect and in later years after the advent of hyperconjugation (1939) as its predecessor. A fundamental problem with the effect is that differences in the observed order are relatively small and therefore difficult to measure accurately.
Hyperconjugation model for explaining the gauche effect in 1,2-difluoroethane. Key in the bent bond explanation of the gauche effect in difluoroethane is the increased p orbital character of both C−F bonds due to the large electronegativity of fluorine. As a result, electron density builds up above and below to the left and right of the ...
Negative hyperconjugation is a theorized phenomenon in organosilicon compounds, in which hyperconjugation stabilizes or destabilizes certain accumulations of positive charge. The phenomenon explains corresponding peculiarities in the stereochemistry and rate of hydrolysis .
Cinnamaldehyde is a naturally-occurring compound that has a conjugated system penta-1,3-diene is a molecule with a conjugated system Diazomethane conjugated pi-system. In theoretical chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in a molecule, which in general lowers the overall energy of the molecule and increases stability.
Free-radical intermediate is stabilized by hyperconjugation; adjacent occupied sigma C–H orbitals donate into the electron-deficient radical orbital. A new method of anti-Markovnikov addition has been described by Hamilton and Nicewicz, who utilize aromatic molecules and light energy from a low-energy diode to turn the alkene into a cation ...
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...