Related Experiment Video
Updated: May 24, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Synthesis and crystal structure of hydroxyacetophenone Schiff bases containing propargyl moiety: solvent effects on
V Selvarani1, B Annaraj, M A Neelakantan
1Chemistry Research Centre, National Engineering College, K.R. Nagar, Kovilpatti 628 503, Thoothukudi District, Tamil Nadu, India.
Abstract:
Four tetradentate (N(2)O(2)) and tridentate (NO(2)) Schiff base compounds (L1-L4) with propargyl moiety were prepared by the condensation of 1-[2-hydroxy-4-(prop-2-yn-1-yloxy)phenyl]ethanone with various aliphatic amines. The newly synthesized compounds (L1-L4) were characterized on the basis of the results of elemental analysis, thermal analysis, FT-IR, (1)H NMR spectroscopic studies and single crystal X-ray crystallography. The different bands observed in the electronic spectra of the compounds in various organic solvents have been assigned to the proper electronic transitions. The hydrogen bonding and tautomeric equilibria in both of solution and the solid state are explained. The solvatochromism of the synthesized compounds in different solvents in the UV-visible spectra are discussed.
Related Concept Videos
UV–Vis Spectroscopy: Woodward–Fieser Rules
IR and UV–Vis Spectroscopy of Carboxylic Acids
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Spectroscopy of Carboxylic Acid Derivatives
In the...
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in the...
