Related Experiment Video
Updated: Jul 19, 2026

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals
Published on: May 25, 2016
Medium effects on zwitterionic-biradicaloid intermediates from two phenyl-alpha-oxoamides. Irradiations in fluid and
Carlos A Chesta1, Mathew George, Chuping Luo
1Department of Chemistry, Georgetown University, Washington, DC, USA. cchesta@exa.uncr.edu.ar
Abstract:
The photochemical processes of two N,N-dialkyl phenyl-alpha-oxoamides, N,N-diisopropyl phenyl-alpha-oxoamide (1) and N,N-dibenzyl phenyl-alpha-oxoamide (2), are investigated at different temperatures in methanol and ethylene glycol (to probe the influences of H-bonding and viscosity), in the solid phase of D-sorbitol at room temperature (to compare with the results in the liquid alcohols and to assess the influence of a poorly organized "stiff" environment), in the neat solid phase (to probe the influence of well-ordered, "stiff" matrices), and in the solid, smectic A2 and isotropic phases of methyl-tris-tetradecylphosphonium tetrafluoroborate (1P14BF4) (to assess the ability of the intermediates to respond to subtle changes in the order and polarity of their local environments). From differences between the activation parameters for product pathways from irradiations in methanol and in 1P14BF4, we conclude that the zwitterionic pre-product intermediate from 1 is much more sensitive to the polarity, viscosity and order of its local environment than is the isomeric pre-product biradicaloid intermediate or either of the pre-product intermediates from 2. A very sensitive balance among the medium parameters, as well as internal steric and electronic factors of 1 and 2, controls the reactive pathways of the photochemically generated intermediates.
Related Concept Videos
Radical Substitution: Allylic Bromination
Radical Reactivity: Steric Effects
Along with electronic factors, steric factors also account...
Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction

