Synthesis, characterization and quantum chemical investigation of molecular structure and vibrational spectra of 2,5-dichloro-3,6-bis-(methylamino)1,4-benzoquinone

• 2,5-Dichloro-3,6-bis-(methylamino)1,4-benzoquinon(dmdb) has been synthesized and characterized.
• FT-IR spectra and FT-Raman of dmdb have been recorded and analyzed.
• Molecular structure, NBO analysis, HOMO–LUMO analysis, MESP and thermodynamic functions have been computed and analyzed.

2,5-Dichloro-3,6-bis-methylamino-[1,4]benzoquinone has been synthesized by condensing methyl amine hydrochloride with chloranil in presence of condensing agent sodium acetate. FT-IR (4000–400 cm−1) and FT-Raman (4000–400 cm−1) spectral measurements of dmdb have been done. Ab initio and DFT (B3LYP/6-311+G**) calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies, infrared intensities and Raman activities. The optimized molecular structure of the compound is found to possess C2h point group symmetry. A detailed interpretation of the observed IR and Raman spectra of dmdb is reported on the basis of the calculated potential energy distribution. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO energy gap reveals that the energy gap reflects the chemical activity of the molecule. The thermodynamic functions of the title compound have also been computed.

MEP plot of dmdb molecule is reproduced here.Figure optionsDownload as PowerPoint slide