Related Experiment Video
Updated: Jun 16, 2026

Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
Published on: August 19, 2013
A density functional study towards substituent effects on anion sensing with urea receptors
Amrita Ghosh1, D Amilan Jose, Amitava Das
1Central Salt and Marine Chemicals Research Institute (CSIR), Bhavnagar, 364002, Gujarat, India.
Abstract:
Effects of substituents on anion binding in different urea based receptors have been examined using density functional (B3LYP/6-311+G**) level of theory. The complexes formed by a variety of substituted urea with a halide anion (fluoride) and an oxy-anion (acetate) have been calculated. The stronger complexes were predicted for receptors with fluoride ion than that of acetate ion, however, in water the preference was found to be reversed. The pK ( a ) calculations showed the preferred sites of deprotonation for positional isomers, while interacting with anions. The position of the substituent in the receptor, however, could change the preferred sites of deprotonation compared to the site predicted with pK ( a ) values. Figure The substituent effects on anion binding towards different urea receptors have been examined by DFT with B3LYP/6-311+G** level of theory.
Related Concept Videos
Basicity of Aromatic Amines
Structure of Amines
Basicity of Heterocyclic Aromatic Amines
Basicity of Aliphatic Amines
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
Substituent Effects on Acidity of Carboxylic Acids
Diazonium Group Substitution: –OH and –H
