Related Experiment Video
Updated: May 11, 2026

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
Molecular structure and vibrational spectra studies on antipyrine derivative, 4-(2,3,4-trihydroxybenzylideneamino)
Lekun Liu1, Hongwei Gao, Zhaozhe Cui
1Institute of Watershed Science and Environmental Ecology, Wenzhou Medical College, Zhejiang 325035, China.
Abstract:
The molecular geometry, theoretical harmonic frequencies and infrared intensities of 4-(2,3,4-trihydroxybenzylideneamino) antipyrine (THBAP) were calculated using different density functional methods (LSDA, mPW1PW91, B3LYP and HCTH) with various basic sets, including 3-21G, 6-311G, LanL2DZ, and SDD. The purpose of this research is to compare the performance of different density functional theory (DFT) methods at different basis sets in predicting geometry and vibration spectrum of THBAP. The optimized geometric band lengths and bond angles obtained by using mPW1PW91 at both LanL2DZ and SDD basic sets show the best agreement with the experimental data. A comparison between the observed fundamental vibrational frequencies of THBAP and the calculated results has been made and the result indicates that the mPW1PW91/6-311G level is superior to all the remaining levels for predicting all the vibration spectra on average for THBAP.
Related Concept Videos
NMR Spectroscopy of Benzene Derivatives
NMR Spectroscopy of Aromatic Compounds
Structure of Amines
Basicity of Heterocyclic Aromatic Amines
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

