enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound. It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [ 1 ]

  3. Hammett equation - Wikipedia

    en.wikipedia.org/wiki/Hammett_equation

    This effect is depicted in scheme 3, where, in a para substituted arene 1a, one resonance structure 1b is a quinoid with positive charge on the X substituent, releasing electrons and thus destabilizing the Y substituent. This destabilizing effect is not possible when X has a meta orientation. Scheme 3. Hammett Inductive Mesomeric Effects

  4. Electrophilic aromatic directing groups - Wikipedia

    en.wikipedia.org/wiki/Electrophilic_aromatic...

    However, another effect that plays a role is the +M effect which adds electron density back into the benzene ring (thus having the opposite effect of the -I effect but by a different mechanism). This is called the mesomeric effect (hence +M) and the result for fluorine is that the +M effect approximately cancels out the -I effect.

  5. Hyperconjugation - Wikipedia

    en.wikipedia.org/wiki/Hyperconjugation

    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.

  6. Phenyl group - Wikipedia

    en.wikipedia.org/wiki/Phenyl_group

    It is often said the resonance stability of phenol makes it a stronger acid than that of aliphatic alcohols such as ethanol (pK a = 10 vs. 16–18). However, a significant contribution is the greater electronegativity of the sp 2 alpha carbon in phenol compared to the sp 3 alpha carbon in aliphatic alcohols.

  7. Naturally occurring phenols - Wikipedia

    en.wikipedia.org/wiki/Naturally_occurring_phenols

    In female elephants, the two compounds 3-ethyl phenol and 2-ethyl 4,5 dimethylphenol have been detected in urine samples. [70] Temporal glands secretion examination showed the presence of phenol, m-cresol and p-cresol (4-methyl phenol) during musth in male elephants. [71] [72] [73] p-Cresol and o-cresol are also components of the human sweat.

  8. Ferric chloride test - Wikipedia

    en.wikipedia.org/wiki/Ferric_chloride_test

    The ferric chloride test is used to determine the presence of phenols in a given sample or compound (for instance natural phenols in a plant extract). Enols , hydroxamic acids , oximes, and sulfinic acids give positive results as well. [ 1 ]

  9. COSMO-RS - Wikipedia

    en.wikipedia.org/wiki/COSMO-RS

    Quantum chemical effects like group-group interactions, mesomeric effects and inductive effects also are incorporated into COSMO-RS by this approach. The COSMO-RS method was first published in 1995 by A. Klamt. [1] A refined version of COSMO-RS was published in 1998 [5] and is the basis for newer developments and reimplementations. [6] [7] [8 ...